Flexible endoscopic surgical robots provide enhanced access and maneuverability in complex anatomical environments, addressing limitations encountered by conventional rigid robotic systems. However, achieving precise control of these robots remains challenging due to inherent nonlinear hysteresis originating from friction and tendon slack in tendon-driven mechanisms, significantly impacting surgical accuracy and increasing the cognitive workload on surgeons. To overcome these challenges, this study introduces MonoEndoCal, a deep learning-based autonomous calibration framework designed to estimate bending angles and compensate for nonlinear hysteresis using only monocular endoscopic images, without the need for additional sensors or markers. Leveraging advanced vision models-Depth Anything V2 for dense depth estimation and Segment Anything Model 2 for zero-shot segmentation-MonoEndoCal accurately estimates robot bending angles in real-time. These angle estimations, along with corresponding actuation commands, are employed to derive a precise hysteresis model using differential equations capturing the robot's nonlinear dynamics. By integrating this hysteresis model with robot kinematics, MonoEndoCal implements an effective feedforward control strategy that enables precise hysteresis compensation and enhanced control accuracy. Experimental validations further demonstrate its robustness across varying robot geometries, input characteristics (both periodic and aperiodic), and blood contamination, highlighting its strong potential for improving control precision. Note to Practitioners-Flexible endoscopic surgical robots are increasingly used to enhance precision and reduce patient trauma in minimally invasive procedures. However, accurate control remains challenging due to nonlinear hysteresis in tendon-driven mechanisms, which can significantly affect surgical performance. This work presents MonoEndoCal, a deep learning-based autonomous calibration framework that uses only monocular endoscopic images-without external sensors or markers to estimate bending angles and compensate for hysteresis in real time. From a practical perspective, the proposed method can be integrated into existing endoscopic robotic platforms with minimal hardware modification, making it well-suited for clinical environments with strict space constraints. Practitioners adopting this framework should ensure that real-time computational resources are available and validate the hysteresis model with system-specific calibration data to achieve optimal performance. This approach offers a cost-effective, sensorless calibration solution that can improve control fidelity and reduce surgeon workload in tendon-driven surgical robots.

The awareness for preserving privacy in in-home monitoring robots is increasing. Although several studies have proposed privacy-preserved in-home monitoring robot systems for adults, only a limited amount of attention has been paid attention to research on privacy-preserved in-home monitoring of babies. Like previous studies, thermal infrared image-based methods could ensure a privacy-preserved monitoring of babies, yet when existing detection methods were applied to thermal images to detect babies and adults, we discovered a frequent occurrence of misdetection due to the presence of thermal residual heat marks. In this research, we propose a sequential thermal image-based detection that conjugated the characteristics of thermal residual heat marks. The proposed detection reduced misdetection caused by thermal residual heat marks by 98.7% when compared to RetinaNet. In addition, we open-source our collected thermal image-based baby and adult dataset via: https://github.com/donkeymouse/ThermalAdultandBaby.

Tendon-driven flexible endoscopic surgical robots have been developed to access narrow curved paths without incision. Robot shape information is essential for precise control and to prevent unwanted tissue damage. In this paper, we propose a joint angle sensing method using coiled soft sensors to estimate the shape of the hyperredundant manipulator, which is commonly used in flexible endoscopic surgical robots. The soft sensors can be fabricated with small size and are highly stretchable, such that by being pre-stretched, they can be integrated between individual joints, maintain a center hollow, and sense both compression and extension. The pre-stretch length is experimentally selected by using the sensor linearity to maximize the potential sensitivity. We validated the proposed design using a two-degree of freedom (DOF) single joint manipulator by implementing two sensors; sensors at all joints could sense joint angle independently and simultaneously with a root-mean-square error (RMSE) less than 2.53°. Based on the proposed method, a two-DOF configuration of the hyperredundant manipulator that can be used in real applications was achieved, following a constant curvature model in real time with values RMSE of 2.30° and 2.63°, for pitch and yaw joint angle respectively.

Face spoofing detection could be used in conjunction with face recognition or facial expression recognition in social robots for better interaction with the users. Recent works have employed thermal image-based spoofing detection due to its competitive spoofing detection performance. However, existing methods utilized indoor thermal images which put a limit on using thermal image-based spoofing detection in outdoor environments. Moreover, several thermal image-based spoofing detection datasets consist of facial images at a frontal viewpoint, which would be put a limit on the usage in social robots with short heights. In this paper, we present our novel thermal image dataset for spoofing detection in outdoor environments. Unlike most existing datasets, our dataset is collected in outdoor environments with the camera facing the upper view to simulate the viewpoint of a social robot. To cover diverse outdoor environments, the dataset was collected at varying locations, times, and weather. Furthermore, we trained an event recognition-based spoofing detection on our collected dataset and also have provided benchmarking results for several baselines. Our spoofing detection method based on MobileNetV2 yielded a spoofing detection accuracy of 96.04% and GFLOPs of 0.88. Our dataset will be open-sourced for users pursuing academic research and will be available upon request to the authors.

The trend of achieving minimal invasiveness in surgeries and recent technological advances in robotics have resulted in the emergence of flexible surgical robots. Such flexible robots can reach a surgical site via narrow and tortuous pathways, extending the reach of robotic surgery and potentially reducing the incision size. This review covers the key technical issues associated with flexible surgical robotics and introduces emerging flexible surgical robot systems organized according to their target applications in the endoluminal surgical field. Furthermore, the challenges and recent advancements in manipulator design, modeling, and control as well as the shape and force sensing of flexible robots are presented as key technical issues. Furthermore, the technical features and clinical values of emerging flexible surgical robot systems are introduced with their medical applications.

Many surgical robots with steerable surgical instruments have been proposed for endoscopic surgery. Surgical instruments should be small in size for insertion into the body and be able to handle large payloads such as tissue. Because the overall diameter and payload parameters are a trade-off, it is difficult to design an instrument with a large payload while reducing its diameter. In this paper, we optimize the payload of a rolling joint mechanism by deriving the moment equilibrium equation and constraints for endoscopic surgery. A scaled-up prototype was fabricated with the design variables obtained from the optimization, and the validity of the method for calculating the payload was confirmed by the experimentally measured payload. By plotting the distribution of payloads obtained from the moment equilibrium equation, we also confirmed that the payload obtained from the optimization is the maximum. In addition, optimizations with different numbers of joints confirm that the payload tends to decrease as the number of joints increases. This payload optimization method could also be extended to minimizing the deflection of the bending section against external forces and minimizing the diameter of the surgical instrument given the minimum required payload.

The use of flexible endoscope has been rising inconveniences. Steering of the distal section is not intuitive and the weight of the endoscope burdens a physical pressure on physicians who use it continuously for a long time. Also, the limited dexterity of an instrument makes therapeutic procedures more difficult, and further the unintended communications often occur during cooperation with assistants. These degrade the efficiency and thus increase the procedure time. In this paper, we propose a robotic endoscopy system (easyEndo) that can be mounted on a conventional endoscope and facilitate solo-endoscopy with two intuitive hand-held controllers. Furthermore, a robotic arm is presented that can be attached to the endoscope to assist with tissue traction. To validate the robotic endoscopy system, experiments to simulate biopsy and lesion marking were conducted with novices. The results showed that the robotic manipulations improved efficiency and reduced workload than manual manipulation. Subsequently, a prototype of the robotic arm was attached at the distal end of the endoscope, and the feasibility of tissue traction was confirmed by a simulation of pulling a rubber band.

The use of the tendon-sheath mechanism (TSM) is common in flexible surgery robots, because it can flexibly work in limited spaces and provides efficient power transmission. However, hysteresis from nonlinearities such as friction and backlash poses a challenge in controlling precise motion in the surgical instrument. Moreover, this hysteresis is also affected by changes in the various configurations of sheath which limits traditional model-based compensation approaches. Recently, feedback approach using an endoscopic camera is presented, but they use markers which are not appropriate for applying to a real surgical instruments. In this paper, a novel hysteresis compensator with learning-based pose estimation is proposed. Unlike previous studies, the proposed compensator can reduce hysteresis of the surgical instrument in various sheath configurations without using markers. In order to estimate an actual angle of the surgical instrument's joint, we employ the learning-based pose estimation using a siamese convolutional neural network (SCNN). The proposed compensator reduces hysteresis by partially controlling the position command, similar to the instinctive adjustments that physicians make with their visual feedback. To validate the proposed method, a testbed was constructed considering several requirements of flexible surgery robots. As a result, the results show the proposed method reduces hysteresis to less than 10°, for various configurations of sheath. In addition, we confirmed that the learning-based pose estimation is sufficient to apply to the proposed compensator for reducing hysteresis in real-time.

Endoscopes are widely used for not only intraluminal diagnosis but also therapeutic procedures in the gastrointestinal area. However, conventional endoscopes present a few challenges such as nonintuitive manipulation, physical burden on the operator, and lack of dexterity. These challenges limit endoscope usage in complex surgical procedures. Moreover, endoscope operators undergo extensive and lengthy training to attain an adequate skill level. In this paper, we introduce a flexible surgery robot platform K-FLEX that facilitates teleoperation via an intuitive master interface and bimanual manipulation by means of two dexterous surgical robot arms. Its effects on endoscopic procedures, especially in terms of task performance, learning properties, and physical burden on the operator, are validated by conducting a user test. The experimental results demonstrate that the developed robotic assistant increases operation speed, especially for novices; simplifies the learning process; and reduces the workload on the operator compared to conventional endoscopes.

With the growth of the social robot market, much research has been undertaken on facial expression recognition, which is an important function of a social robot. Facial expression recognition models have shown good performance in a facial expression image dataset that expresses emotion without considering speaking effect. However, in reality, humans often express emotions by speaking and moving the muscles around the mouth. Therefore, the lack of consideration of speech leads to unsatisfactory emotion recognition results. In this paper, we investigated two points to be considered in learning a facial expression recognition model. First, we confirmed whether the information around a mouth induces the recognition model in speech act to misrecognition like the case of a facial expression recognition in non-speech acts or it has valid information for facial expression recognition. Second, Generative Adversarial Network (GAN)-based data augmentation has been performed to cover the problem in which the accuracy of the recognition model in speech acts is low because of the relatively small variance about the subject in RML dataset. The results showed that the information around the mouth made facial expression recognition in speech acts exhibit higher performance, unlike the case of facial expression recognition in non-speech acts. In addition, the GAN-based data augmentation alleviated the accuracy degradation in facial expression recognition because of the low variance of the dataset.

This study presents an age and gender estimation system that considers ethnic difference in face images using a Convolutional Neural Network(CNN) and Support Vector Machine(SVM). Most age and gender estimation systems using face images are trained on ethnicity-biased databases. Therefore, these systems show limited performance on face images of ethnic groups occupying a small proportion of the training data. To resolve this problem, we propose an age and gender estimation system that considers the ethnic difference in face images. At the first stage of the system, the ethnicity of the facial image is determined by a CNN trained with manually collected face images of Asian and non-Asian celebrities. Then, one of the SVM classifiers is selected according to the ethnicity for the final age and gender estimation. We compared the proposed system with an estimation system that does not consider ethnic difference. The result shows improved performance for age estimation but no improvement for gender recognition.

In robotics, robotic arms should be smaller, less expensive, and able to demonstrate a better performance, in order to be utilized in various fields. However, expensive actuators and speed reducers are required to generate sufficient force at the end effector after overcoming the gravitational torque of robotic arm. Robotic arms become compact and cost effective if the gravitational torque can be passively compensated. Especially in the field of robotic laparoscopic surgery, the static equilibrium state of the robot arm in the entire workspace is essential to achieve both safety and ease of use. In this study, we propose a novel passive gravity compensation mechanism based on springs and wires. This mechanism utilizes a scotch yoke mechanism to compensate the gravitational torque changed by two rotational degrees of freedom (DOF). Furthermore, we applied to a surgical robotic arm which was constructed using a roll-pitch joint. According to the experiments, it was proved that the new mechanism effectively compensate the gravitational torque. As a result, compact and cost-effective robotic arms can be developed satisfying safety and ease of use.

Fall detection systems have been proposed to prevent additional injuries following fall accidents. This paper introduces an easily learnable fall detection system based on the data of an individual patient in a hospital room. The improvement of low performance using a single accelerometer at wrists and the inconvenience of sensor attached to a waist in the conventional approach was concentrated on by integrating heart rate signals to the conventional acceleration approach and changing the sensor location from a waist to wrists. As for the optimal heart rate feature selection, we proposed a four-feature vector combination (root mean square of successive differences, standard deviation of successive differences, normal to normal 50, normal to normal 20) with correlation and mutual information analysis in addition to mean absolute deviation selected as an accelerometer feature. To easily acquire and train the patients' fall data, our system was based on unsupervised learning approaches using Gaussian mixture models for optimal classifiers with the optimal cluster number decided by cluster validation index of square error sum. A 10-fold cross validation was applied for a final performance evaluation where each threshold for separating fall state from non-fall state was automatically decided in several comparison groups, which were created on the basis of fusion timing and used sensors. As a result, despite sensors attached to the wrist, the wearable inconvenience of the conventional is overcome using the feature-level fused approach between heart rates and accelerations with the accuracy up to 98.39 %, which is closest to 99.34 % of the case using a single accelerometer located at the waist.

We present a baseline convolutional neural network (CNN) structure and image preprocessing methodology to improve facial expression recognition algorithm using CNN. To analyze the most efficient network structure, we investigated four network structures that are known to show good performance in facial expression recognition. Moreover, we also investigated the effect of input image preprocessing methods. Five types of data input (raw, histogram equalization, isotropic smoothing, diffusion-based normalization, difference of Gaussian) were tested, and the accuracy was compared. We trained 20 different CNN models (4 networks × 5 data input types) and verified the performance of each network with test images from five different databases. The experiment result showed that a three-layer structure consisting of a simple convolutional and a max pooling layer with histogram equalization image input was the most efficient. We describe the detailed training procedure and analyze the result of the test accuracy based on considerable observation.

Needs and studies on service robot are growing with rapid market extension. Generating human-like motions on robot is one research area of human-robot interaction. There are several studies about motion generation and humanoid design. However, kinematic analysis of humanoid design for service tasks should also performed. This paper focuses on motor alignment of humanoid shoulder. After we measure human greeting gestures with 3D capture camera and predefine workspace, simulation is performed to find motor alignment on humanoid shoulder to minimize total required motor power. Result shows that there are specific alignment for designing shoulder to perform greeting tasks on small motor powers.

Air purifiers and humidifiers, the popular home appliances, have a large working space by injecting and controlling air, which spreads over a house. The air circulation inside a room limits the efficiency of air purification, the disparities of which vary with environmental factors, such as room shape, temperature, furniture arrangements, and human movement. In this study, mobility provided by mobile robot technology is combined with a conventional air purification function. This robotic appliance can improve air purification efficiency, which depends on the air injections and filtration. In our experiments, the effectiveness of the mobility is verified and the commercial growth potential, as a new type of smart home service robot is discussed.

A horseback riding simulator is developed to overcome challenges occurring on real horses. The goal of the simulator is to provide a real horseback riding-like sensation to the user in various situations with limited workspace. This paper focuses on generating various trajectories at different walking speeds with dynamic effects. A walking horse dynamic model is purposed based on a two-linked rimless wheel and is modified with 3D-captured data from a real horse. A controller is also designed for passing and compression-recoil modes, aiding in changing the models walking speed using speed change input. A dynamics simulation is performed and results show that the suggested walking model covers trajectory with measured data and shows more variation.

Driving assistance systems (DASs) can be useful to inexperienced drivers. Current DASs are composed of front rear monitoring systems (FRMSs), lane departure warning systems (LDWSs), side obstacle warning systems (SOWSs), etc. Sometimes, DASs provide unnecessary information when using unprocessed low-level data. Therefore, to provide high-level necessary information to the driver, DASs need to be improved. In this paper, we present an intelligent driving assistance robotic agent for safe driving. We recognize seven driving situations, namely, speed bump, corner, crowded area, uphill, downhill, straight, and parking space, using hidden Markov models (HMMs) based on velocity, accelerator pedal, and steering wheel. The seven situations and global positioning system information are used to generate a situation information map. The developers of a navigation system have to tag driving events by themselves. In contrast, our driving assistance agent tags situation information automatically as the vehicle is driven. The robotic agent uses the driving situation and status information to assist safe driving with motions and facial and verbal expressions.

The aim of this research is to develop a quantitative usability evaluation method (UEM) for elderly drivers, which has different weight values on each factor concerning physical and cognitive context of elderly drivers. An analysis of the relationship between universal design guidelines for elderly drivers and usability principles was conducted by using the quality function deployment method. In addition, developmental priorities are derived from analysis results of difficulty in achieving performance improvement, max relationship values, and relative weight. Furthermore, n and positive relationships among the universal design guidelines are defined by means of relationship analysis. Combining these results, a quantitative evaluation guideline for elderly drivers is derived, and based on the context and developmental goals of the developer, selective design is facilitated. The proposed UEM is compared with existing UEM in terms of thoroughness, validity, and effectiveness.

For a service robot, touch is one of the major interaction components. However, because many robot designs and touch sensor arrangements are designed by a company, actual user interactions do not match the implemented sensors in the robot. So it is necessary to investigate practical human touch patterns without advanced user knowledge of the robot's touch sensor. This study seeks to measure the influence of pointed and smooth-shaped protrusion types on touch interactions with an egg-shaped robot. Based on the results, a pointed protrusion creates distributed touch interaction while a smooth-shaped protrusion concentrates touch interaction.

In this paper, we propose a novel unified framework for unsupervised object individuation from RGB-D image sequences. The proposed framework integrates existing location-based and feature-based object segmentation methods to achieve both computational efficiency and robustness in unstructured and dynamic situations. Based on the infant's object indexing theory, the newly proposed ambiguity graph plays as a key component of the framework to detect falsely segmented objects and rectify them by using both location and feature information. In order to evaluate the proposed method, three table-top multiple object manipulation scenarios were performed: stacking, unstacking, and occluding tasks. The results showed that the proposed method is more robust than the location-only method and more efficient than the feature-only method.

A rider communicates with a horse to control the horse. This type of communication, collectively known as riding aids, is important in horse riding. When the rider communicates with the horse during horse riding, the horse determines the rider's command with its own intelligence and controls its own motors. We expect that probability factors can represent the riding aids and they can be used to control the horse. Therefore, we propose a probability model of riding aids, especially weight aids. To estimate the probability of the weight aids, we devised a sensor-equipped saddle that measures the vertical force. These sensors calculate the Center of Gravity (COG). In experiments, the rider rides on the horse with the sensor-equipped saddle and the sensors record the COG data depending on the rider's commands. Finally, we formulated the probability of the weight aids as rider commands. The probability of weight aid can be a prior probability of other riding aid probability, and we expect that the rider can control a horse robot simulator with theses probability models.

In this paper we propose a haptic interaction system that physically represents the underlying geometry of objects displayed in a 2D picture, i.e., a digital image. To obtain the object's geometry captured in the picture, we estimate the physical transformation between the object plane and the image plane based on homographic information, which locates the face of the object that is viewed. We then calculate the rotated surface normal vector of the object's face and place it on the corresponding part in the 2D image. The purpose of this setup is to create a force that can be rendered along with the image without distorting the visual information. For example, if a user is touching or exploring a 2D image, he/she receives resistive force when touching a slanted face. We evaluated the proposed haptic rendering scheme using a set of pictures of objects with different orientations. The experimental results show that the participants reliably identified the geometric configuration by touching the object in the picture. We conclude with developed applications of the proposed algorithm.

This paper presents a new miniature haptic display to convey ample haptic information to a user of a handheld interface. There are buttons on interfaces or general electronic devices, but existing buttons provide haptic feedback of only one passive pattern to a user. Because humans perceive tactile and kinesthetic information simultaneously when they handle objects, the proposed actuator provides both sensations at once. It is able to generate various levels of kinesthetic sensations when pressing a button under diverse situations. Also, vibrotactile feedback can be delivered for exciting haptic effects with numerous patterns. Its performance was evaluated in accordance with the resistive force by changing the intensity of the input current. Experiments show that the proposed actuator has the ability to provide numerous haptic sensations for more realistic and complex haptic experiences.

Operating in unstructured dynamic human environments, it is desirable for a robot to identify dynamic objects and robustly track them without prior knowledge. This paper proposes a novel model-free approach for probabilistic representation and tracking of moving objects from 3D point set data based on Gaussian Mixture Model (GMM). GMM is inherently flexible such that represents any shape of objects as 3D probability distribution of the true positions. In order to achieve the robustness of the model, the proposed tracking method consists of GMM-based 3D registration, Gaussian Sum Filtering, and GMM simplification processes. The tracking performance of the proposed method was evaluated in the moving two human hands with one object, and it performed over 87% tracking accuracy together with processing 5 frames per second.

In this paper, we propose a novel multiple object tracking method from RGB-D point set data by introducing the hierarchical spatiotemporal data association method (HSTA) in order to robustly track multiple objects without prior knowledge. HSTA is able to construct not only temporal associations between multiple objects, but also component-level spatiotemporal associations that allow the correction of falsely detected objects in the presence of various types of interaction among multiple objects. The proposed method was evaluated using the four representative interaction cases such as split, complete occlusion, partial occlusion, and multiple contacts. As a result, HSTA showed significantly more robust performance than did other temporal data association methods in the experiments.

Driving assistant systems are becoming the attractive service tasks in the field of intelligent robotics. Humans meet a variety of situations while driving cars and robotic systems help humans to understand how surrounding situations change and how robot systems are aware of given situations. From the viewpoint of interaction performance, proper situation awareness by a robotic assistant in a car and the relevant determination of corresponding reactions are crucial prerequisites for long term interaction between a human driver and a car's robotic system. In this paper, we focus on preserving human-robot interaction for driving situations, considering how many types of cognitive situation occur and how affective interaction can be designed for the robotic driving assistant. The appropriateness of the driving situation and of the robotic reactions are testified in our experiment system, including the development of a virtual driving environment and tablet-based robotic agent system.

The proposed system using sympathetic reaction will make people control environment more naturally. People don't need to consider environment as independent and abstract object but the object that can be interact emotionally.

This paper proposes a deterministic approach to track people in a populated environment from 2D depth data by a laser range finder attached on a mobile robot. This work aims to improve robustness of multiple people tracking in the presence of change of the number of people, missing data, and long-term occlusions by using spatiotemporal data association. The temporal data association method is based on the multi-frame tracking (MFT) and the improved MFT (IMFT) is proposed for enhancing computational efficiency in the long-term occlusions. A spatial data association algorithm used a matching algorithm from the leg history data for detecting a human subject from leg tracks. The proposed methodology has been assessed in the three walking patterns of two people and compared with MFT and MHT methods.

Because declining rates of population growth have left aging societies in many countries around the world, Smart Walker systems were created to assist elderly people in managing their physical, cognitive, and emotional challenges. While the main application of the Smart Walker is to assist in the daily life of the elderly, it may also be used to assist in rehabilitation. In this paper, a no-contact system is proposed to motivate exercise on a Smart Walker. A tablet device is attached to the chair in front of the user to serve as a channel for interaction. The tablet device has several modalities for expression including a 3D robot-face character, TTS (Text to Speech), and dialog messaging. The exercise motivational system selects appropriate expressions to display on the tablet device, from pre-recorded behavioral data, using real-time data from the movements of the patient.

For social interaction, information of smartphone should be delivered efficiently. In this study, we will use text reading method, user registration method, and time analyzing method to read context of smartphone. Furthermore, we will use teddy bear robot to express proper emotional behavior for given information so that user can intuitively understand the context of information.

There have been many attempts made by companies and researchers to make people feel more familiar with robots. As one example, Dance performance of Entertainment Robot could conceivably provide an event that would be seen easily in a public place. In most cases, however, programmers' and researchers' workload, if they were to attempt to program dance motions for a robot and synchronize them, would be too heavy. In addition, pre-programmed dance motion and synchronization information are useful only for one certain music and are useless for any other music input. To solve these problems, we have introduced a new system that can make a robot dance automatically with real-time music input. The system consists of two main parts: the first is a real-time beat extraction system for music; the second one is a system of dance motion for a humanoid robot. In the first part, music input is analyzed using FFT and peak-to-peak time duration in the low frequency area is computed. In the second part, the process of making and synchronizing the dance motion of the humanoid robot is described. Finally, we perform experiments to check the validity of the proposed system. Also, limitations and further work are described.

Emotional interaction has been widely applied to many robotic applications. Emotional behavior, which is complementary to limited cognitive ability in a service robot, is becoming the attractive service task even including its own therapeutic functions. This paper focused on the user study of an interactive affective companion by using a cleaning robot as a pet. The cognitive and emotional subsumption model is designed for the robust behavior selection with the response to human's commands. In addition, we testified the appropriateness of long-term interaction through tablet-based modality.

This paper discusses an unified method of the tracking and balancing controls for leg-wheel hybrid structures in an effort to improve the mobility over hard, flat surfaces. Preliminarily, we analyzed the contact constraint to formulate a dynamically decoupled model in the task space. Then, inequality constraints were determined to restrict the dynamic behavior of the system within the given bounds for the dynamic stability and the actuator saturation. The inequality constraints were applied to the reference control input that was designed for the mechanism to traverse the desired trajectories without the constraints. To find the constrained control input, a quadratic objective function was proposed to minimize the modification error of the control inputs. We tested the effectiveness of the proposed algorithm by comparing simulation results with our previous research.

This paper discusses a balance control method with kinodynamic constraints for leg-wheel hybrid structures in an effort to improve the mobility of locomotion over hard, flat surfaces. Preliminarily, we defined a prioritized Jacobian and a prioritized inverse of Jacobian to formulate the dynamically decoupled model in the task space for the constrained multi-contact multi-rigid-body system with a floating base. Our strategy has two tracks to accommodate the uncertainty and the complexity of the system dynamics. 1) The time-delay estimation and control are combined with the nonlinear programming. 2) Whole kinodynamic constraints are derived as functions of the control input. The proposed balance control algorithm allows the system to traverse desired trajectories satisfying the kinodynamic constraints and improves the mobility of locomotion. The effectiveness of the algorithm is tested with the dynamic simulations.

In order to achieve effective interaction between humans and robots, user interface system is one of important factors. To achieve a valid and appropriate user interface system, we have introduced a new system that consists of a beam projector that can display images for interacting with users and a laser scanner that can detect user's foot motion so that the system recognizes user's input and intention. In this paper, we have focused on how to cause projected images to be rectangular so that users can interact with ordinary rectangular images instead of trapezoidal images that will be produced if the beam projector attached on the robot projects images sideling and how to distinguish user's foot motions according to two classifications, drag motion and click motion. Finally, we have executed a test for checking the validity of the proposed system and have examined limitations and proposed further work for this system.

Haptic and audio cues now appear commonly in computer interfaces, partially due to inherent advantages such as their support for eyes-free interaction. Their invisible, unobservable nature also makes them ideal candidates for security interfaces in which users have to enter secret information such as passwords. In particular, researchers have explored this idea through the design of PIN entry authentication systems based on multi-modal combinations of visual and non-visual content or on the recognition of small sets of unimodal haptic or audio stimuli. This paper highlights the benefits and performance limitations of these approaches and introduces an alternative based on unimodal audio or haptic temporal numerosity - the ability to accurately and rapidly determine the number of cues presented in rapid temporal succession. In essence, in a numerosity interface, rather than recognizing distinct cues, users must count the number of times that a single cue occurs. In an iterative process of design and evaluation, three prototypes implementing this concept are presented and studies of their use reported. The results show the fastest PIN entry times and lowest error rates to be 8 s and 2%, figures that improve substantially on previous research. These results are attained while maintaining low levels of workload and substantial resistance to observation attack (as determined via camera attack security studies). In sum, this paper argues that unimodal audio and haptic numerosity is a valuable and relatively unexplored metaphor for non-visual input and demonstrates the validity of this claim in the demanding task of unobservable authentication systems.

This paper presents a novel method to develop a human–robot attitudinal relationship based on intimacy. For a robot to estimate human's intimacy, we propose a fuzzy space model to classify intimate human behavioral patterns. Proxemic, tactile, and oculesic behavioral features, which are dominantly used for intimacy exchange in human–human communication, are analyzed to develop the 3-D intimacy space. The proposed model provides social standards to develop an intimacy-based attitudinal relationship between a human and a robot. We analyze the generality of our model through a sample interaction scenario and discuss how intimacy can be incrementally learnt for a long-term interaction between a robot and a human.

To augment tangible information into current social network systems (SNSs), this paper proposes an algorithm that generates force data from the user's hand gestures. The input modality defined in this paper is based on gesture information in the form of an acceleration profile in that at times it describes the current status of a user better than text-based content. For the physical representation of a motion update, corresponding force vectors in a Cartesian coordinate system are calculated with the proposed linear equation. Given the experimental results, it is predicted that the proposed physical logging and rendering scheme will provide a physical experience in mediated social connections.

This paper proposes a new interactive interface TAXEL, which aims at developing a reconfigurable self-morphing visio-haptic interface. We first present the overall architecture and concept of a self-morphing visuo-haptic interface. Key hardware components are developed and tested, including three tactile actuators using a piezoelectric active linear actuator, a passive MR fluid actuator, and a thin film-type actuator, respectively, and a flexible visual display based on the light-waveguide technology. Using the developed components, a tactile platform that includes a 8×16 array of the linear actuators is implemented for a proof of concept. A rendering engine is also designed for the tactile platform with emphasis on the use of haptic feedback together with GUI. We also carried out a user study with virtual button simulation as a benchmark to evaluate the performance of the TAXEL tactile platform. Lastly, an integrated system with a visual display is demonstrated along with several application examples.

This paper presents a new subminiature impact type actuator which creates the haptic sensation in a mobile device. Recently, linear resonance actuators (LRA) are widely used. One of the key differences between an LRA and a traditional eccentric motor is that the LRA generates the vibrotactile sensation through resonance for minimizing response time. The strategy of operation near the resonant frequency, however, brought a new issue for creating vibrotactile sensation which can be strong enough to feel in arbitrary frequency. In order to achieve this issue, we adopt an unstable structure to amplify impact force and to reduce response rate. Due to the impact with fast rising and falling time in the proposed impact actuator, the available strong impact vibration is created over wide frequency range from 0Hz to 100Hz. The impact vibration generated from the proposed actuator is suitable for reproducing realistic button sensation and creating various vibration patterns in mobile devices.

This paper proposes a balance control algorithm which uses Zero Moment Point (ZMP) in order to improve the mobility of leg-wheel hybrid structures on hard, flat surfaces. The algorithm generates balancing leg motions which continuously adjust the contact points to allow the geometric center of the contact area to follow ZMP. During our simulation of a balance control system which uses Individual Joint PD Control (IJPD), we encountered two main problems-high frequency oscillation and unbalanced control input. To solve these issues, we derived a method for dynamic decoupling and control allocation (DDCA). We tested the effectiveness of the proposed algorithm by simulating the maximum distance that a robot can stably move during a fixed time period. There are three important advantages to our proposed balance control algorithm. First, the balancing motions have no effect on the primary tasks of its arms and upper body. Second, the interaction forces between the contact points are minimized, thereby reducing an unbalance of the control inputs. Third, the task dynamics are decoupled and controlled independently.

This paper proposes a balance-control algorithm which uses the Zero-Moment Point (ZMP) in order to maximize the dynamic stability of leg-wheel hybrid structures on hard, flat surfaces. The algorithm constrains the control input to satisfy the condition in which the ZMP stays at the geometric center of the contact area. This restriction of the control input changes the original fully actuated system into an under-actuated system and generates a problem with the internal dynamics. To solve this issue, we found output variables which reduce and stabilize the internal dynamics by means of an Input/Output Linearization (IOL) process. We tested the effectiveness of the proposed algorithm by comparing three cases in a simulation - no balance control, ZMP feedback balance control, and ZMP feedforward balance control.

This paper proposes a dual-layer user model to generate descriptive service recommendations for user-adaptive service robots. The user model represents user preferences as the associative memory in the bottom-layer and association rules in the top-layer. The learning and inference processes in the two layers, and the bottom-up rule extraction process, are explained. The proposed user model was applied to a user-adaptive coffee menu recommendation system, and the quantitative and qualitative performances of the user-adaptive and descriptive recommendation system were evaluated by comparison with non-descriptive and random recommendation methods.

As the number of mobile robot applications increases, research related to physical contact between humans and robots is becoming an important issues in the service robot domain. In this paper, a mobile robot platform based on spring loaded casters is proposed as solution to problems in the service robot domain. A simple dynamic equation in two dimensions was computed and the dynamic characteristics according to variation of the elastic coefficient were analyzed. In order to detect force from a human, a linear equation was formulated by regression of the driving data. With the estimated force, an impedance model is applied to the controller for compliance. Through this process, it is shown that the proposed mobile robot platform is capable of a compliant reaction to external force through of its posture, similar to unstable mobile platform, though the mobile platform has the static stability.

Tangible user interfaces are portals to digital information. In the future, securing access to such material will be an important concern. This paper describes the design, implementation and evaluation of a PIN entry system based on audio or haptic cues that is suitable for integration into such physical systems. The current implementation links movements on a mobile phone touch screen with the display of non-visual cues; selection of a sequence of these cues composes a password. Studies reveal the validity of this approach in terms of task times and error rates that improve over prior art. In sum, this paper demonstrates the potential of non-visual PINs as a mechanism for securing access to a range of systems, ultimately incorporating mobile, ubiquitous or tangible interfaces.

Research on tangible interaction and digital haptics has rarely intertwined, despite the natural relationship between physicality and touch. This paper addresses this relatively unexplored domain by presenting the Haptic Wheel, a freestanding single-axis rotational controller incorporating vibro-tactile cues. In addition to describing the hardware and implementation, the paper discusses the potential application of the system for eyes-free interaction, password entry and as an active puck on a tabletop system. The paper suggests that systems with active haptic feedback have unexploited potential as tools for tangible interaction.

Authentication in public spaces poses significant security risks. Most significantly, passwords can be stolen, potentially leading to fraud. A common method to steal a PIN is through an observation attack, either using a camera or through direct observation (e.g. shoulder-surfing). This paper addresses this problem by presenting the design and implementation of a novel input keypad which uses tactile cues as means to compose a password. In this system, passwords are encoded as a sequence of randomized vibration patterns, making it visually impossible for an observer to detect which items are selected. An evaluation of this system shows it outperforms previous interfaces which have used tactile feedback to obfuscate passwords.

Design of reactive emotion generation mechanism for interactive robots is proposed in this paper. Sorts of reactive emotions and the framework to generate these emotions against stimuli were identified based on psychological researches on humans' emotions. Computational models of reactive emotion system were also proposed with dynamic models. Each model realized necessary characteristics for reactive process successfully. The developed model was implemented in a toy-like robot which is called `GOMY'. The robot can show emotional response reactively against stimulus change. The proposed reactive emotion model can be considered as the most basic foundation of general emotional process for interactive robots.

In this paper, a robotic user interface (RUI) as an information management system is described. There have been numerous studies regarding 2D- or 3D-based GUIs that attempt to overcome the disadvantages of a hierarchal structure in information handling. Here, the GUI system is extended to RUI in a technique that enhances its capacity to store and recall by exploiting a spatial/functional association between semantic categories and body parts. A robot resembling a bear was implemented for the evaluation of this association. Experimental results revealed that information can be clustered on a specific body part with statistical significance. Information storage and retrieval becomes easier because there is no need for maintenance or memorization of a location in which specific information is stored. In addition, the fact that a robotic interface can be used in parallel with an existing desktop-based system enhances work efficiency.

Human intention recognition is one of the most important research areas in the human-robot interaction in order to accomplish more natural and intelligent interaction. In the public service area, the basic four human intentional actions, `approach', `depart', `bypass', and `stop' were investigated by the human's movement pattern. In order to recognize those four human intentional actions, the mobile robot measured 360 degree distance between a robot and a human by two IR-scanner sensors, and three problems were solved: 1) human detection and tracking by improved K-means clustering method, 2) absolute human velocity estimation by extended Kalman filter, and 3) inferring intentional actions by HMM with position-dependent observation model. The result showed as quite good performance that inferred the probabilities of those four intentional actions.

In order to achieve a believable interaction between humans and robots, synthesizing the reasonable and natural emotion is important. Furthermore, improving the adjustability of parameters' values in the model is essential for the designer of a robot. In this paper we developed a hybrid emotion generation architecture and defined the generalized context inputs of emotion generation model for convenient use by a robot designer. We also developed the personality model based on the Big-Five personality factors to generate the various emotions and action colorings. The personality model affected not only the intensity of the generated emotion, mood state, and emotion decay, but also the action selection of the robot. So, for each circumstance, the robot can show the distinct emotional state and modified actions, which we call action colorings. The developed emotion generation system is integrated into a robot which responds to the user's calling, and manages the schedule of the human.

This paper describes the design idle motions which service robots act in its standby state. In case of the robots developed so far, they show proper reactions only when there is a certain input from human or environment. They cannot perform in a standby state which means there is no input. If a robot does not make any motion in its standby state, users may feel that the robot is being turned-off or even out of work. On the other side, if the robots can make idle motions such like human at the standby state, then they are expected to make people feels that they are alive and is more likely to interact with them. In order to find the behavioral patterns at the standby state, we observed clerks at the information center via video ethnography, and idle motions are extracted from video data. We analyzed idle motions, and apply extracted characteristics to our robot. Moreover, by using the robot which can show those series of expression and action, our research needs to find that people can feel like they are alive.

In this paper, multi-fingered tactile display modules are proposed. Each tactile display module is comprised of a 4 times 4 piezoelectric ultrasonic actuator array with a spatial resolution of 1.5 mm and a temporal resolution of 20 Hz. The objective of this research is to build a small and lightweight tactile display system so that the system including the display modules and complete controller parts is wearable by a user. It was found that various types of texture information can be generated using a static indentation or through the vibration of each pin. Three tactile display modules were utilized for interaction with a 3D virtual environment. As the developed tactile display modules consume less power and are connected wirelessly to a host PC, the system is applicable to various types of texture representation systems.

Touch is obviously an important channel along with vision and speech for natural human robot Interaction. However, as most service robots are generally specialized for their own service, touch-centered shape design and additional costs/computation less related to their own tasks can represent a limit to the application of a touch system on a service robot. This paper originated from the motivation to apply a touch system with lower costs/computation to robots without design modifications. The proposed touch recognition system features hardware that is simply composed of charge-transfer touch sensor arrays, an accelerometer and a temporal decision tree classifier intended for online recognition and computational time reduction. Experiments performed by 12 people shows the practicability of the system. The results showed an average recognition rate of 83% with respect to the 4 touch patterns of hit, beat, rub and push.

This paper describes the design of a new robot head which has three special parts for emotional expression. The emotion of robots has become an issue of interest in the field of robotics. This robot head, EEEX(exaggerating emotion expresser) is developed to efficiently express various emotions. EEEX is useful in the human-robot interaction. EEEX has 3 special elements that humans do not possess to clearly express emotions. The first is arm-type antennae which consist of a 3-DOFs link system on each side to make dynamically emotional movements. They are specialized parts to show emotion by copying the humanpsilas arm motion. Second, emoticon-eyes help to represent emotions intuitively since the eyes are the most important parts to convey emotions. Lastly, exaggerating jaw & cheeks when expressing exaggerative emotions should assist in emotional expression as well, particularly surprise and anger. These 3 parts, the arm-type antennae, emoticon-eyes and exaggerating jaw & cheeks, would help human to recognize a robotpsilas emotions more clearly.

The electric inductance sensor is often used for automatic guided vehicles (AGV) owing to its high reliability that originates from the compactness of its line tracking. However, tracking a single line leads to the design problems in the path layout on a floor when there is a requirement to move in a highly configurable space. The limitation of a single and continuous line has restricted line tracking to simpler rather than more complex spaces in which a robot is required to execute various tasks and where a few crossways are included. In this paper, circular sensor arrays based on electric inductance are proposed for a service robot. This technique enables a robot to recognize the shape of a path using a clustering method and enables it to perform various local motions based on the relative position and orientation measured from the path on the ground.

In this paper, a compact tactile display which consists of multiple vibrotactile actuators with 4-different vibrotactile unbalanced masses and a Peltier thermoelectric module is proposed. By stimulating 2 different sensory channels including mechanoreceptors and thermoreceptor simultaneously, surface texture and material composition can be displayed using the implemented device. 3 experiments were conducted for the performance evaluation of the proposed device through discriminating various patterned textures. Experimental results show that the developed device can be used to display surface texture and temperature together and suggest the possibility of implementing a small-sized, multi-fingered tactile display device.

In human-robot interaction (HRI), interactivity is a critical issue in terms of how they understand each other and what makes them share grounds to communicate. This paper proposes measures to evaluate interaction process using information theoretic approach. The measures are designed to quantify the level of shared ground among agents and their environment. With these measures, an experiment is carried out in which human subjects were asked to interact with a virtual robot to assign tasks with voice interface. The results of the experiments show that the measures are useful in measuring the interactivity of HRI.

In this paper, a sound synthetic technique (SST) based on sinusoidal frequency modulations with irregular primitive function algorithms for tactile perception is suggested. Investigations of the benefits of real-time SST for haptic interaction were referenced. Performance was evaluated in two ways; 1) a unimodal analysis of synthesized sounds in terms of whether they can induce tactile perception, and 2) multimodal analysis of the relationship between tactile perception and the generated sound. The unimodal analysis of sound suggested that meaningful spectrum contents can be generated using the proposed SST. The result of the multimodal analysis showed that auditory-haptic multimodal perception increases human sensitivity of texture perception.

Social capability of a robot becomes one of important issues in human-robot interaction (HRI). Especially, for a robot to form a social relationship with people is significant for improving believability of a robot through more natural communication with people. In this paper, we propose a formal approach to make a robot establish and learn a social relationship based on affective relation in sociological perspectives. The main idea is based on representing sentiment relation (liking/disliking) within social individuals, which is regarded as a basis for forming interpersonal relation in sociology. Our Sentiment Relation model can be applied to loyalty implementation of service robots in underlying assumptions that a service robot must have high positive relationship to her host and tends to behave to minimize tension(stress) by unbalanced states, which are generated by different affective states between individuals in social group. To confirm the possibility of our model, the reinforcement learning-based behavior coordination using loyalty level is simulated in the simple grid world.

In interacting with a soft object, both visual and haptic senses play major role in providing the characteristics of the object. While visual feedback comes from the appearance of the overall shape, haptic feedback comes largely from the localized internal composition. However, it has been a common practice to represent the object with one model for both processing shape de formation and computing the feedback force, making it much challenging work to achieve real-time simulation of a soft and especially non-homogeneous object. In this paper, we claim that it may be sufficient to represent the graphical visual model as a surface model whereas it is necessary to represent the haptic model as a volumetric model. We propose, therefore, a hybrid model where volumetric haptic model and surface graphical model coexist. For constructing hybrid model, we employ S-chain model to compute the haptic behavior and mass-spring model to calculate graphic behavior. We conduct experiments with volumetric human liver model at a haptic update rate of 1000 Hz and graphic update rate of 30 Hz. The experimental results show that our proposed model satisfies the real-time performance and provides the realistic sense to be useful for a virtual reality application.

This paper introduces an emotion interaction system for a service robot. The purpose of emotion interaction systems in service robots is to make people feel that the robot is not a mere machine, but reliable living assistant in the home. The emotion interaction system is composed of the emotion recognition, generation, and expression systems. A user's emotion is recognized by multi-modality, such as voice, dialogue, and touch. The robot's emotion is generated according to a psychological theory about emotion: OCC (Ortony, Clore, and Collins) model, which focuses on the user's emotional state and the information about environment and the robot itself. The generated emotion is expressed by facial expression, gesture, and the musical sound of the robot. Because the proposed system is composed of all the three components that are necessary for a full emotional interaction cycle, it can be implemented in the real robot system and be tested. Even though the multi- modality in emotion recognition and expression is still in its rudimentary stages, the proposed system is shown to be extremely useful in service robot applications. Furthermore, the proposed framework can be a cornerstone for the design of emotion interaction and generation systems for robots.

In this paper, the feasibility of multiple targets localization with a ultrasonic transmitter and only two ultrasonic sensors are tested and its results are given. For this purpose, an experimental hardware system and algorithm which models after bat's vocalization and auditory pathway are built. To mimic bat's behavior features, bat's chirp composed of single band/full band signal component and frequency response in bat's cochlear are modeled after. Time delay estimation is made by cross correlation and deconvolution between transmitting signal and its echoes. As a result, the combination of full band signal and filterbank shows the best performance and the reason is analyzed The physical and theoretical constraints of this approach for multiple targets localization are analyzed and some possible solutions for the improvement are proposed.

For the development of for mental model of intelligent robot, in this paper we deal with a cognitive modeling system based on the cognitive process of human being, using psychoanalysis and two kinds of emotion theories, artificial intelligence, neural network and fuzzy Petri net. Based on the psychoanalysis of Freud, we graph the psychiatric structure named 'mind sketch' by KNBN(Kohonen Network based on Belief Network). Within the mind sketch, 'emotion' is used as the base for making relative data. It is based on the emotion theory of Plutchick and the cognitive emotion theory of Ortony et al. To combine these emotional theories, a fuzzy Petri net algorithm has been proposed. And a cognitive modeling system has been developed.

This paper proposes a tactile display device providing pin-array type tactile feedback and thermal feedback. The pin-array type tactile display is composed of a 6times5 pin-array that is actuated by 30 piezoelectric bimorphs. Micro shape and vibrotactile feedback can be generated by the device, and various planar distributed patterns can be displayed as can braille cell patterns. The thermal feedback device is composed of a thin film resistance temperature detector (RTD), a Peltier thermoelectric heat pump and a water cooling jacket. Users can discriminate among different materials by considering the temperature variation that can be sensed as they touch an object's surface. This paper also includes an experimental evaluation of the device to prove effectiveness of displaying textures. Material property discriminating evaluation was conducted using thermal feedback device that displays simulated temperature profile. To determine the relation between stimulated area and thermal perception sensitivity, a thermal perception experimental setup is developed and the experimental method is described

This paper describes an experiment on the evaluation of human sensibility by monitoring responses to changes in the frequency and amplitude of a tactile display system. Preliminary tasks were performed to obtain adequate adjectives concerning texture presentation. And, in the main experiment, 7 selected sandpaper types and 15 selected combinations of frequencies and amplitudes of a tactile display were utilized to quantitatively evaluate the ten adjectives determined during preliminary tasks. The data show that a relationship exists between the independent variables (frequency, amplitude, and grit size) and the dependent variable (perceived texture). We then considered the perceived tactile perception in relation to viscoelastic properties of the human fingerpad. We obtained remarkable psychophysical results and also identified the relation between tactile sensation and the mechanical stimuli from a biomechanical viewpoint

This paper presents a novel haptic mouse KAT (KAIST artificial touch) that can be used as a human-computer interface and offers the capability of displaying properties such as patterns, gratings and roughness. A small planar-distributed pin array is developed. The array can represent micro-scale shapes with various surfaces, such as gratings, grooves, patterns, shapes of icons, and Braille, and provides the user with cutaneous stimuli. Since the tactile display unit is small enough to be embedded into a computer mouse, we developed a new texture display mouse. The performance of its texture display capability was verified. In addition, two psychophysical experiments have been conducted in order to ascertain the influence of vibrotactile stimuli. The first experiment showed that vibrational stimuli could be effective in the perception of patterns while from the second experiment, the functional relation between perceived roughness and components of vibrotactile stimuli was obtained. The experimental results have been applied to the development of a test-bed program

Tangible interface is a newly defined concept, which provides effective and seamless interaction between a human as a subjective existence and a cyberspace as an objective existence. As one of the tangible interface, tactile interface is essential for many exploration and manipulation tasks in the tangible space. In this paper, we suggest a design of an integrated tactile sensor-display system that enables both of tactile sensing and display with kinesthetic force, pressure distribution, and vibration. A human-like tactile sensing system with PVDF strips and a display system with bimorph actuators have been developed and integrated in the tangible space. In the demonstration scenario of haptic navigation in the tangible space, the developed tactile sensing to display system is successfully experimented.

In human-robot interaction, interactivity is a critical issue in terms of how they understand each other and how they make other party understand efficiently. In this paper, this issue is approached formally with respect to the mental model and shared ground. A formal model of human-robot interaction based on the information theory is presented in order to explain the mechanism of human-robot interaction and the role of shared grounds and the mental model of human-robot interaction. It is expected that the presented model of H-R interaction will increase the understanding of human-robot interaction, and may be useful in classifying, describing and predicting this interaction process

The sense of touch provides humans with the ability to determine the shape and surface properties of objects. Although touch is an important part of daily life for object manipulation and exploration tasks, users are, unfortunately, rarely provided with the opportunity to use their sense of touch while interacting with computers. To rectify this, this article presents a novel haptic mouse system that can be used as a human-computer interface with the capability for holistic haptic feedback, including contact force, surface properties, and thermal feedback. The system is composed of 3 main parts. First, the 5-bar mechanism, which comprises the lowermost part of the mouse's body, has been adapted to realize 2-DOF translational force feedback. This mechanism helps the user to feel the contact force, stiffness, and size of a virtual object while exploring a graphical environment. Second, a small tactile display was developed. It has a planar-distributed pin array, and it can represent microscale shapes with various surfaces, such as gratings, grooves, patterns, shapes of icons, and Braille, thereby providing the user with cutaneous stimuli. Third, because the ability to sense temperature is an important factor in the discrimination of the surface property of an object, thermal feedback is provided to the user. The performance of each part and their combinations has been evaluated, and the system shows a remarkable ability to provide users with tactual information while they simply use the mouse without any additional interfaces.

In this paper, we suggest a mouse-type integrated tactile display system that provides kinesthetic force, distributed pressure, vibration and skin stretch. The system consists of two parts: a 2-DOF force feedback mechanism for kinesthetic force display and a tactile display part for providing normal stimulation to the skin and the lateral skin stretch. A tactile display device, using eight piezoelectric bimorphs and a linear actuator, is fabricated and attached to a 2-DOF translational force feedback device to simultaneously simulate the texture and stiffness of the object. The developed system was adopted as a test bed to study the factors affecting perception of surface properties. We investigate three things: effective stimulating methods, limitation of surface discrimination based on kinesthetic force and the effectiveness of combining kinesthetic force feedback with tactile feedback. Seven kinds of stimulating methods are investigated to study effective methods in simulating texture. In addition, in order to find out the role of skin stretch during perceiving texture, the discernment abilities of active touch (rubbing), laterally-active-display and moving-wave-form have been compared.

A noisy behavior of the time domain passivity controller during the period of low velocity is analyzed. Main reasons of the noisy behavior are investigated through a simulation with a one-DOF haptic interface model. It is shown that the PO/PC is ineffective in dissipating the produced energy when the sign of the velocity, which is numerically calculated from the measured position, is suddenly changed, and when this velocity is zero. These cases happen during the period of low velocity due to the limited resolution of the position sensor. New methods, ignoring the produced energy from the velocity sign change, and holding the control force while the velocity is zero, are proposed for removing the noisy behavior. The feasibility of the developed methods is proved with both a simulation and a real experiment.

This paper is aimed at developing the control method of multiple degree-of-freedom (DOF) hybrid haptic interfaces with active/passive actuators. After the mathematical description of the kinematic requirements of multiple DOF haptic interfaces with passive actuators, we outline the concept of the control method based on the passivity. The fundamental consideration of the passivity is examined by following the "power observer" (PO) approach. The "switching control" (SC) is outlined briefly and then proposed the "bridging control" (BC) comparing with SC. To evaluate the feasibility of the proposed BC/PO, the experiments were conducted via 2-DOF hybrid haptic interface which is a five-bar-linkage mechanism with two motors and two MR brakes.

This paper describes a novel haptic mouse system which conveys kinesthetic and tactile information simultaneously in virtual environments. The haptic mouse system can provide 2-DOF translational force feedback, vibration, normal pressure, skin stretch and thermal feedback, all of which are important physical quantities of sensing object's shape, stiffness and surface properties. The system can simulate small scale shapes and roughness of surface textures using cutaneous cues generated by individual drives of a 6/spl times/8 pin array. Since thermal differences among surfaces of virtual objects is one of dominant factors in perceiving texture, a thermal feedback unit composed of a heat conduction plate and a temperature sensor is also embedded into the tactile display system. The developed system can be used as a testbed in psychophysical study on tactile perception. We have investigated the influence of the frequency variation on perceived roughness using the haptic mouse system since vibrotaction has been considered as a key factor affecting perception of fine textures by physiology researchers. In order to find out the relation of roughness and vibration, two psychophysical experiments have been performed. The correlation between the vibration frequency and the texture shows that there are certain transitions of perceived roughness. The experimental results yield that the vibrating stimulus is more effective for displaying a fine surface than static displacement display, and it shows a possibility to display finer texture, exceeding the physical limitation of the device.

A noisy behavior of the time-domain passivity controller during the period of low velocity is analyzed. Main reasons of the noisy behavior are investigated through a simulation with a one-DOF haptic interface model. It is shown that the PO/PC is ineffective in dissipating the produced energy when the sign of the velocity, which is numerically calculated from the measured position, is suddenly changed, and when this velocity is zero. These cases happen during the period of low velocity due to the limited resolution of the position sensor. New methods, ignoring the produced energy from the velocity sign change, and holding the control force while the velocity is zero, are proposed for removing the noisy behavior. The feasibility of the developed methods is proved with both a simulation and a real experiment.

Tactile sensation is essential for many exploration and manipulation tasks not only in a real environment but also in a virtual environment. We suggest the design of an integrated tactile display system that provides kinesthetic force, pressure distribution, vibration and slip/stretch. The system consists of two parts: a 2 DOF force feedback device for kinesthetic display and a tactile feedback device for displaying the normal stimulation to the skin and the skin slip/stretch. Psychophysical experiments measure the effects of fingerpad selection, the direction of finger movements and the texture width on tactile sensitivity. We also investigate the characteristics of lateral finger movement while subjects perceive different textures. From the experimental results, the principal parameters for designing a tactile display are suggested. A tactile display device, using eight piezoelectric bimorphs and a linear actuator, is implemented and attached to a 2 DOF translational force feedback device to simultaneously simulate the texture and stiffness of the object. As a result, we find out that the capability of the suggested device is sufficient to display physical quantities for tactile sensing.

Physical damping is essential to achieve passivity in haptic display. To improve stability, an additional physical damper was used with motor. This fixed damping approach, however, has limitation to display free motion, so that the motor actually has to work for damping cancellation. This paper suggests that the controllable damping approach without necessity for damping cancellation to improve both stability and performance. Firstly, we analyze the effect of the controllable physical damping on stability and also propose a controllable physical damping approach applying controllable magnetorheological brake to haptic display. Finally, we experimentally show the contribution of the proposed controllable physical damping approach to the performance in terms of Z-width.

This paper describes the development of a compact laparoscopic assistant robot system which functions as a camera assistant in laparoscopic surgery. The system allows 3-DOF motion and is mountable to a standard laparoscope holder. The 3-DOF motion includes 1-DOF translation and 2DOF bending motion for adjusting viewpoints. This compact system is designed so that viewing angles are adjusted within the abdomen using a bending section and thus, interference with the operating surgeon is reduced. Voice-controlled command input and visual-servoing are implemented for the control of the robot. Our preliminary experiments show a possible clinical use upon further improvement.

A new bilateral control scheme is proposed to ensure stable teleoperation under a wide variety of environments and operating speeds. System stability is analyzed in terms of the time-domain definition of passivity. A previously proposed energy-based method is extended to a 2-port network, and the issues in implementing the "passivity observer" and "passivity controller" to teleoperation systems are studied. The method is tested with our two-degrees-of-freedom master/slave teleoperation system. Stable teleoperation is achieved under conditions such as hard wall contact (stiffness >150 kN/m) and hard surface following.

A new method to control a flexible manipulator with noncollocated feedback is proposed. We introduce a method to implement the time-domain passivity-control approach to a flexible manipulator with noncollocated feedback, which could not be treated with the previous time-domain passivity-control framework due to a possible active transfer function from the input to the noncollocated output. The proposed method is simulated with a single-link flexible manipulator, and a good control performance is obtained.

This paper presents a novel haptic mouse system as a new human computer interface, which has a force feedback capability. A proposed haptic mouse can reflect 1 dof grabbing force as well as 2 dof translation force which can simulate more realistic virtual experience. Five-bar mechanism has been adapted to realize the 2 dof translation force feedback, and double prismatic joint type of mechanism has been used to implement the grabbing force feedback. Wire-driven mechanism is mainly used for actuation to reduce the backlash as well as to provide back-drivability. In addition, haptic rendering algorithm for the proposed haptic mouse have been developed to give feelings of weight, shape and surface texture. By adding haptic information to the visual and audio information, the haptic mouse system is expected to be useful by presenting more realistic interaction in e-commerce in the future.

A new interfacing method is presented to control mobile robot(s) in a supervised manner. Mobile robots often provide global position information to an operator. This research describes a method whereby the operator controls a mobile robot(s) using his finger or stylus via a touchpad or touch screen interface. Using a mapping between the robot's operational site and the input device, a human user can provide routing information for the mobile robot. Two algorithms have been developed to create the robot trajectory from the operator's input. Information regarding numerous path points is generated when the operator moves his finger/stylus. To prune away meaningless point information, a simple but powerful significant points extracting algorithm is developed. The resulting significant points are used as waypoints. An on-line piecewise cubic Bezier curves (PCBC) trajectory generation algorithm is presented to create a smooth trajectory for these significant points. As the method is based on distance and not on time, the velocity of mobile robot can be controlled easily within its allowable dynamic range. The PCBC trajectory can also be modified on the fly. Simulation results are presented to verify these newly developed methods.

This paper presents a learning cooperation strategy based on fuzzy Q-learning in the interactive robot soccer game. The interactive robot soccer game bas been developed to let humans join in the game dynamically and entertain them more. Accordingly, cooperation strategy between humans and autonomous robots is very important for making the game more realistic. Autonomous robots move to their destination depending on the current positions of other robots and the ball. These destinations based on situation will be learned with the fuzzy Q-learning method through playing the game with human operators. In order to evaluate the usefulness of the proposed strategy for the cooperation between humans and robots, the simulation with a modeled human operator and the game with real human operators have been carried out.

This paper describes a bone-mountable surgical robot system for hip surgery and its in vitro experiments with cadavers. The system eliminates the need for obtaining CT scan data by adopting gauge-based, bone-mounting registration method and is designed to replace only the broaching procedure, which is known to be the most error-prone procedure in the manual surgery. The performance of this system is evaluated with specimen of six human cadavers. X-ray images and photographed image of femurs are utilized for measuring the difference between the implant and the anatomical axes. As this deviation implies how the gait pattern of the operated patient may be influenced by the surgery, the amount of deviation is used as the indicative of system performance. The nominal differences of anteversion angle, valgus-varus angle, and flexion-extension angle are 0.02/spl plusmn/2.73/spl deg/, 0.98 /spl plusmn/0.39/spl deg/ and 0.51/spl plusmn/0.87/spl deg/, respectively. In case of the change in leg length after the surgery, the nominal error is -0.88/spl plusmn/1.26 mm. Experimental results show that the performance of the developed system is comparable to other surgical robots that use preoperative planning with CT scan data.

This paper presents a gauge-based registration method, a femur-mountable robot for hip arthroplasty named ARTHROBOT, and the surgery procedure using this system. In the gauge-based registration, a reamer-shaped gauge is inserted into the femoral medulla for relative positional information of the femur to the robot. A mounting frame and a minirobot are then mounted on the patient's femur for accurate machining. This gauge-based registration method drastically reduces the processes in preoperative planning by eliminating the need of computer tomography scanning or other image processing methods, compared to other robotic systems that are used for hip surgery. Also, this surgical system reduces damage to the femur because only the metaphyseal region of the femoral canal needs to be machined, while leaving the diaphyseal hard bone untouched. Experiments were performed on 18 composite bones and 12 pig bones. In the composite bone group, orientation (anterversion, varus/valgus and flexion/extension) errors were made at 0.13/spl deg//spl plusmn/0.77/spl deg/, 0.14/spl deg//spl plusmn/0.38/spl deg/, and -0.27/spl deg//spl plusmn/0.33/spl deg/, and the maximum position error was at 1.00 mm. In the pig bone group, orientation errors were made at -0.03/spl deg//spl plusmn/0.65/spl deg/, 0.31/spl plusmn/0.27/spl deg/, and -0.36/spl deg//spl plusmn/0.36/spl deg/, and the maximum position error was at 1.12 mm. Also, 93% of the gaps between the bone and the implant surface were under 0.25 mm. The developed system shows sufficient machining accuracy and precision for clinical application.

This paper describes the design and implementation of a hybrid active/passive force feedback device. It has a single degree of freedom that is actuated by a motor and a brake pair. The use of a motor and a brake allows various objects to be simulated without a stability problem and related safety issues involved with using high torque motors only. The device performance is measured by its ability to simulate various test objects. Simple test objects are modeled as a benchmark test of the system's performance. The force feedback device is capable of simulating forces in a variety of virtual environments. This device demonstrates the effectiveness of a hybrid active/passive haptic actuator. An analysis of the use of hybrid active/passive actuators in the 2 degrees of freedom case finds that they are capable of simulating a rigid body in a broad range.

This paper presents the mechanism and surgical method for ARTHROBOT, a new surgical robot for hip arthroplasty. The robot is femur-mountable and capable of 4-DOF motion. It uses a new gauge-based registration method that utilizes measuring instrument consisting of a reamer-shaped block gauge and a distance-measuring device. This gauge-based registration method drastically reduces the processes in the preoperative planning by eliminating the need of inserting fiducial markers or CT scanning. From the preliminary performance evaluation, it is shown to have less than 0.3 mm machining error, which seems to be sufficiently accurate for clinical application. Since the system has low operating cost and is compatible to the conventional manual surgery, it is expected to be easily adaptable to surgical needs and practices in the operating room.

A new bilateral control scheme is proposed to ensure stable teleoperation under a wide variety of operating conditions. To guarantee the stability of a teleoperation system, a previously proposed energy-based method is extended to a two-port network. The issues in implementing the "passivity observer" and "passivity controller" to teleoperation systems are studied. The method is tested with our two-DOF master/slave teleoperation system. Totally stable teleoperation is achieved under conditions such as hard wall contact (stiffness>150 kN/m) and hard surface following.

This paper presents the KAIST interactive bicycle racing simulator system, which consists of a pair of bicycle simulators. The rider on the racing simulator experiences realistic sensations of motion, while being able to see the other bicycle simulator and having the audio-visual experience of riding in a velodrome or on the KAIST campus. The 2nd bicycle of the racing simulator system consists of a bicycle, a 4-DOF platform, a handlebar and a pedal resistance system to generate motion feelings; a real-time visual simulator a HMD and beam projection system; and a 3D sound system. The system has an integrating control network with an AOIM (Area Of Interest Management) based network structure for multiple simulators.

With an increase in the number of handicapped persons, there is a growing demand for human friendly interface as mobility aids. To meet this need, we have developed two interfaces with using shoulder and head motion for powered wheelchair control. To acquire proper wheelchair control instruction signal, workspaces of shoulder and head are analyzed by magnetic position sensor. Two interfaces are developed to meet four guidelines :human friendly design, easiness of wearability, intuitive drive function, and low cost. FSR (force sensing resistor) is used to measure changes in the shoulder and head motion. Interface's usefulness is verified by clinical experiment with six subjects who are spinal cord injured with C4 or C5.

A new, energy-based method is proposed for guaranteeing the stability of large classes of control systems with minimum performance losses. Based on a network presentation, the large classes of control systems are analyzed in a unified framework. In this unified network model, the concept of passivity is used to study the stability of large classes of control systems. For guaranteeing the stability condition, the time-domain passivity controller is extended to a 2-port network to make the controller 2-port passive. The developed method is tested with numerical simulation in the regulation of a single link flexible manipulator. Totally stable control is achieved under a wide variety of operating conditions and uncertainties without any model information.

This paper presents a new formulation approach for determining the actual solution of the forward kinematics of 6-DOF parallel manipulators. We show that a geometric structure of the 3-6 platform with a 3-2-1 type that has a unique closed form solution provides a useful guideline for formulating the forward kinematics of 6-DOF parallel manipulators and for determining their actual solution. We use the tetrahedron geometry to find the actual solution. The formulation approach is simple and effective for determining the actual solution of many 6-DOF parallel manipulators.

This paper proposes a scheme to produce realistic force reflection in a needle insertion problem. The target system is a spine needle biopsy simulator for tumor inspection by needle insertion. Simulated force is calculated using a 3D human tissue model and the orientation and position of the needle, and is produced through the PHANToM/sup TM/ device. To generate realistic force reflection, the directional force of the needle has been generated by a related tissue model, and the rotational force is generated using a pivot to keep the needle in the initial inserted direction after puncturing the skin. Since the haptic device has limitations in generating high stiffness and large damping, a scale-down model and digital filter are used to stabilize the system.

This paper presents key technologies and system integration issues of the KAIST interactive bicycle simulator. The rider on the bicycle feels the motion and has the visual experience as if he/she is riding in the campus of the Korea Advanced Institute of Science and Technology. The simulator consists of a bicycle, a Stewart platform, a magnetorheological handle, a pedal resistance system to generate motion feelings, a real-time visual simulator and projection system, sub-controllers and an integrating control network.

This paper addresses a wearable master device for physically handicapped persons whose arms are disabled. Optical fiber curvature sensors are used to measure the human body motion. For the developed wearable master device, a calibration and mapping method of the sensors is proposed to extract 2-DOF human shoulder motions. An experiment shows that the wearable master device can be used for a 2-DOF input device effectively for handicapped persons. It has also shown that a subject can control a mobile robot with the wearable master device.

This paper presents a control scheme for obtaining high manoeuvrability of underwater robot manipulators mounted on a remotely operated vehicle (ROV). The motions of an underwater manipulator can affect the attitude and position of the ROV which should remain stationary in seabed operation. To compensate for the dynamic effect of the underwater manipulator on the ROV, the force-torque (F/T) information between the manipulator and the vehicle is used to regulate the states of the ROV. When an F/T sensor is practically unavailable, a disturbance observer can fill the role of the F/T sensor. This paper proposes a disturbance observer for estimating the interaction forces between the ROV and the manipulator. A two-link manipulator mounted on an ROV is considered and numerical simulations are performed to demonstrate the improvement on the manoeuvrability of the proposed controller.

This paper presents a new methodology of using tetrahedron configurations to determine the forward kinematics of 6-DOF parallel manipulators. The approach is introduced in a form of the tetrahedron proposition and theorem using the special characteristics tetrahedral geometry which are then applied to obtaining the kinematic solutions of two 6-DOF parallel manipulators such as those previously introduced by Hunt-Primrose (1993) and by the authors (2000). The proposed methodology has the advantage in greatly reducing the complexity of formulation and computational burden required by conventional methods for solving the forward kinematics. As a result, the methodology allows a significant simplification in the formulations and provides an easier means of obtaining the solution.

We propose a greatly simplified femoral canal shaping method for robot-assisted total hip replacement surgery that requires neither CT/MRI imaging nor insertion of fiducial markers before surgery. A reamer-shaped registration gauge is inserted into the femoral canal and used to position a base for a robot that is mounted on the top of the femur and used to prepare the femoral canal. In a study using 5 fresh cadavers, the average registration error for selected points near the surface of the femoral cavity was 0.59 mm; this is comparable to the errors reported for the geometry-based registration methods.

This paper presents mechanisms and control methods of a new surgery robot for total hip arthroplasty (THA). To minimize the disadvantages of the conventional registration method, a new gauge-based registration method has been proposed, and a 3-DOF robot has been developed that can be mounted on a femur The proposed surgical robot can operate along a pre-programmed path autonomously, in addition to allowing a surgeon to directly control the motion of the surgical robot with their experience and judgment during an operation. For this purpose, a master is attached to the surgical robot and admittance display is used in control. ARTHROBOT this new arthroplastic surgical robot system, is expected to be adaptable to surgical needs and practice in the operating room.

Shows how to implement haptic rendering for a needle insertion problem with a volume graphic model. The target is a spine biopsy simulator for tumor inspection by needle insertion. Simulated force is calculated from the relationship between voxel data and the orientation and position of the needle. At first, it is generated using PHANToM/sup TM./ The needle puncturing resistive force is calculated from a stiffness model and the correction force to give physical constraint to the needle is derived using a pivot. For more realistic force feedback voxel based modeling is considered. MRI T1 value and CT density can be used to give physical properties to voxel. Soft tissue can be modeled as a damper using MRI value in the needle insertion problem, and the stiffness of hard tissue is derived from CT density. Skin deformation is modeled with Kelvin's viscoelastic model. Since the high stiffness and large damping need to be simulated, it is attempted to generate force using active actuators and passive devices together.

Presents an approach to reduce the computational burden of solving the forward kinematics of the 3-6 (Stewart-Gough) Platform. The conventional forward kinematics has been formulated with trigonometric functions through many complicated steps. Based on tetrahedron geometry, the proposed formulation approach can allow intuitive derivation of the forward kinematics and considerable abbreviation of the number of calculations involved in the three constraint equations that must be calculated in the process of the forward kinematics. Consequently, the proposed formulation approach greatly reduces the computational burden. The feasibility and convergence of the formulation approach has been verified through a series of simulation results.

Most of navigation techniques with obstacle avoidance do not consider the robot orientation at the target position. These techniques deal with the robot position only and are independent of its orientation and velocity. To solve these problems this paper proposes a novel univector field method for fast mobile robot navigation which introduces a normalized two dimensional vector field. The method provides fast moving robots with the desired posture at the target position and obstacle avoidance. To obtain the sub-optimal vector field, a function approximator is used and trained by evolutionary programming. Two kinds of vector fields are trained, one for the final posture acquisition and the other for obstacle avoidance. Computer simulations and real experiments are carried out for a fast moving mobile robot to demonstrate the effectiveness of the proposed scheme.

A robust teleoperation controller design method for an underwater manipulator is proposed considering the master and the underwater slave separately. To achieve transparency and stability for a teleoperation of an underwater manipulator in unknown environments with time-varying uncertainties such as added mass, buoyancy, hydraulic drag and friction effect, an adaptive sliding mode control scheme is proposed for robust position tracking control of slave manipulator. To guarantee a force transparency in the master side, disturbance observer is used as a local controller for compensating a friction and coupled nonlinear dynamic effects of the master manipulator. Numerical simulations are performed to demonstrate the transparency and robustness of the proposed controller.

Deals with control and performance evaluation of a two degree-of-freedom five-bar haptic interface driven by harmonic DC servomotors. The presented haptic display has nonlinear effects such as friction and motor cogging which affect impedance fidelity. Force feedback control strategies including a feedforward friction compensator based on joint torque and a disturbance observer have been proposed and are evaluated through experiments. The first set of experiments was conducted to measure how well the impedance fidelity could be achieved for various control strategies. The second set of experiments was conducted to investigate the influence of the control strategies on discontinuity perception and to measure the upper limit of the haptic simulation range of the haptic display.

This paper addresses sensors and actuators for a wearable haptic master device for physically handicapped persons whose arms are disabled. In the first part of this paper, optical fiber curvature sensors are used to measure the human body motion. An efficient calibration and interpolation method of the sensors is then proposed to extract 2-DOF human shoulder motions. In the second part of this paper, solenoid vibrotactile actuators are used to feed back the contact force. Experimental results show that tactile-force substitution is helpful for force regulating tasks and that the frequency and magnitude of vibrotactile stimulus should be increased exponentially to achieve the linearly increased force sensing.

The paper presents a novel adaptive bilateral control scheme for obtaining transparency for teleoperation systems that has uncertainties. It has been found that a condition that is equivalent to getting an ideal response in teleoperation is to making the closed-loop dynamics of master and slave manipulators dual. An adaptive approach is applied to achieve the duality for the uncertain master and slave manipulators. Due to the dual closed-loop dynamic characteristics of master/slave teleoperation systems, excellent position and force tracking performance can be obtained without concerning the impedance variation of human and environment. The validity of the theoretical results is verified by experiments with a 1-DOF master/slave system.

A microsurgical telerobot system has been developed based on the results of the operation task analysis. The telerobot system is composed of a 6-DOF parallel micromanipulator attached to the macro-motion industrial robot and a 6-DOF force-reflecting haptic master device. The master device uses five-bar parallel mechanisms driven by harmonic DC servomotors. The proposed 6-DOF master hand controller has nonlinear coupled dynamics and friction. Since the disturbance force due to friction, gravity and coupled inertia can distort the operator's perception, a disturbance observer is introduced in the operational space and implemented in the microsurgery master hand controller.

A robust controller design method is proposed to obtain a less conservative feedback controller, and applied to a single-link flexible manipulator. The objective is to maximize the control performance guaranteeing the robust stability when regulating the tip position of the flexible manipulator in the presence of a large time varying payload and parameter uncertainties such as stiffness, joint friction. Descriptor form representation, which allows separate treatment of payload uncertainty from other parametric uncertainties, is used to reduce the conservatism of the conventional robust control approaches. Uncertainty of the payload included in the left-hand side inertia matrix and the uncertain parameters included in the right-hand side damping and stiffness matrices are treated with polytopic and descaling techniques, respectively. Using the aforementioned techniques, the robust LQ controller design problem for a flexible manipulator is formulated based on the guaranteed cost approach. Then, the formulated problem has been solved by LMIs.

Presents a gait control algorithm for teleoperation of a quadruped walking robot using gait convergence. A leg trajectory of the walking robot is generated in real-time according to the 3 DOF planar moving velocity command. Initially, the aperiodic gait is applied to follow the unpredictable command, since the periodic gait is known to be optimal and it requires an initial foot position. However, given an arbitrary initial foot position, the proposed algorithm leads the support pattern of the legs to converge from the aperiodic gait to a wave-crab gait or a wave-spinning gait. Further it avoids a deadlock after the directional change of the velocity command. The proposed algorithm has been applied to the walking robot, CENTAUR of KIST that has heavy legs and a large moving area of the gravity center. To compensate the moving gravity center, a sway motion is proposed to transfer the leg of which the kinematic margin is almost zero and the leg trajectory for the sway motion is overlapped with the operator command.

Presents simple but effective nonlinear friction compensation methods for a 3-PRPS (prismatic-revolute-prismatic-spherical joints) in-parallel 6-DOF manipulator. It is well known that an integral action in the feedback controller can remove the steady-state error due to constant disturbance. Thus, the integral-action can compensate coulomb friction, which is the DC-component of the total friction and viscous friction in some degrees. When the direction of position command reverses, the integrator output can not change the sign of its output instantaneously, due to friction at zero velocity, i.e. stiction resulting tracking errors. To overcome this problem we attempt to reverse the sign of the integrator output as the sign of velocity changes. The effectiveness of this approach is demonstrated by experiments on a 3-PRPS in-parallel manipulator. Also discussed are disturbance observer and velocity observer approaches for friction compensation.

A force-reflecting hand controller can provide the kinesthetic information obtained from a slave manipulator to the operator of a telerobotic system. Our goal is to construct a compact hand controller that can provide large workspace and good force-reflecting capability. This paper presents the design and the analysis of a 6-DOF force-reflecting hand controller using fivebar parallel mechanisms. The forward kinematics of the fivebar parallel mechanism has been calculated in real-time using three pin-joint sensors in addition to six actuator position sensors. A force decomposition approach is used to compute the Jacobian. To evaluate the characteristics of the fivebar parallel mechanism, it has been compared with the other three parallel mechanisms in terms of workspace and manipulability measure. The hand controller using the fivebar parallel mechanism has been constructed and tested to verify the feasibility of the design concept and the force reflecting control schemes.

A microsurgical telerobot system has been developed according to the results of the microsurgery task analysis. Several fields of the microsurgery have been investigated and the surgery tasks and tool motions are analyzed to acquire guidelines for specifications of a microsurgical telerobot system. A slave robot system consists of a 6-DOF parallel micromanipulator, that is our own modified Stewart platform type, and a 6-DOF macro-motion industrial robot that mounts the parallel micromanipulator at the end. A 6-DOF force-reflecting master device has also been developed using five-bar parallel mechanisms driven by harmonic DC servomotors. A bilateral control algorithm has been proposed based on the force-position loop, and the local position controller for the master has been developed to minimize the effect of gravity, friction, and inertia.

This paper presents a kinematic analysis of a parallel manipulator for the probing task application that requires high bandwidth, active compliance, anal high precision. Based on the concept of macro/micro manipulators, the parallel manipulator serves as a wrist of a macro manipulator. The developed manipulator is a class of in-parallel platforms with 3 prismatic-revolute-prismatic-spherical (PRPS) joints chain geometry. The main advantages of this manipulator, compared with the typical Stewart platform type, are the capability of pure rotation generation and the easy prediction of the moving platform motion. The purpose of this paper is to develop an efficient kinematic model which can be used for real-time control and to propose systematic methods to design the manipulator considering the workspace, manipulability, resistivity, and existence conditions of the forward kinematic solution. A series of simulation have been carried out to show the kinematic characteristics and performance of the mechanism. A prototype manipulator has been built based on the kinematic design analysis.

This paper presents a kinematic analysis of the parallel manipulator developed for micro-positioning application that requires high control bandwidth and high precision. The manipulator is a class of in-parallel platforms with 3 PRPS (prismatic-revolute-prismatic-spherical) joints chain geometry. The main advantage of this manipulator, compared with the typical Stewart platform type, is the ability to produce pure motion. The purpose of this paper is to develop an efficient kinematic model which can be used for real-time control and to propose systematic design methods that considers the existence conditions of the forward kinematic solution, singularity, manipulability, and resistivity. A series of simulations was carried out to show the kinematic characteristics and performance of the mechanism. The proposed manipulator has potentials in a wide range of applications from micro-surgery robots to a highly dextrous wrist mechanism of assembly robots.

The remediation of single-shell radioactive waste storage tanks is one of the urgent tasks of the Department of Energy that challenge state-of-the-art equipment and methods. The use of long-reach manipulators is being seriously considered for this remediation task. Because of high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to use hydraulic actuators and to exhibit significant structural flexibility. The controller has been designed to compensate for the hydraulic actuator dynamics by using a load-compensated velocity feedforward loop and to increase the bandwidth by using a pressure feedback loop. Shaping filter techniques have been applied as a feedforward controller to avoid structural vibrations during operation. Among various types of shaping filter methods investigated an approach, referred to as a "feedforward simulation filter" that uses embedded simulation, has been presented.

Within the Environmental Restoration and Waste Management Program of the US Department of Energy, the remediation of single-shell radioactive waste storage tanks is one of the areas that challenges state-of-the-art equipment and methods. Concepts that utilize long-reach manipulators are being seriously considered for this task. Due to high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to exhibit significant structural flexibility. To avoid structural vibrations during operation, various types of shaping filter methods have been investigated. A robust notch filtering method and an impulse shaping method were used as simulation benchmarks. In addition to that, two very different approaches have been developed and compared. One new approach, referred to as a "feedforward simulation filter", uses imbedded simulation with complete knowledge of the system dynamics. The other approach, "fuzzy shaping method", employs a fuzzy logic method to modify the joint trajectory from the desired end-position trajectory without precise knowledge of the system dynamics.>