This study introduces a new force-position impedance control strategy tailored for robotic systems engaged in the manipulation of elastic garments. Our approach is innovative for incorporating external force and impedance control within an incremental trajectory generation framework. This method allows for dynamic adjustment to prevent over-deformation and potential damage during garment handling, enabling the fabric to deform to desired states and follow intended trajectory trends without compromising textile integrity. By utilizing external forces in an adaptive, incremental manner, we offer a nuanced solution for expected garment manipulation. Our strategy demonstrates the feasibility of detailed manipulation tasks in industrial settings, bridging the gap between simulated environments and real-world operations. This effort underscores the importance of automation in enhancing textile handling processes, focusing on practical applications rather than theoretical advancements.

Personalization is critical for the advancement of service robots. Robots need to develop tailored understandings of the environments they are put in. Moreover, they need to be aware of changes in the environment to facilitate long-term deployment. Long-Term understanding as well as personalization is necessary to execute complex tasks like prepare dinner table or tidy my room. A precursor to such tasks is that of Object Search. Consequently, this paper focuses on locating and searching multiple objects in indoor environments. In this paper, we propose two crucial novelties. Firstly, we propose a novel framework that can enable robots to deduce Personalized Ontologies of indoor environments. Our framework consists of a personalization schema that enables the robot to tune its understanding of ontologies. Secondly, we propose an Adaptive Inferencing strategy. We integrate Dynamic Belief Updates into our approach which improves performance in multi-object search tasks. The cumulative effect of personalization and adaptive inferencing is an improved capability in long-term object search. This framework is implemented on top of a multi-layered semantic map. We conduct experiments in real environments and compare our results against various stateof-the-art (SOTA) methods to demonstrate the effectiveness of our approach. Additionally, we show that personalization can act as a catalyst to enhance the performance of SOTAs. Video Link: https://bit.ly/3WHk9i9

We present a novel framework for estimating accident-prone regions in everyday indoor scenes, aimed at improving real-time risk awareness in service robots operating in human-centric environments. As robots become integrated into daily life, particularly in homes, the ability to anticipate and respond to environmental hazards is crucial for ensuring user safety, trust, and effective human-robot interaction. Our approach models object-level risk and context through a semantic graph-based propagation algorithm. Each object is represented as a node with an associated risk score, and risk propagates asymmetrically from high-risk to low-risk objects based on spatial proximity and accident relationship. This enables the robot to infer potential hazards even when they are not explicitly visible or labeled. Designed for interpretability and lightweight onboard deployment, our method is validated on a dataset with human-annotated risk regions, achieving a binary risk detection accuracy of 75%. The system demonstrates strong alignment with human perception, particularly in scenes involving sharp or unstable objects. These results underline the potential of context-aware risk reasoning to enhance robotic scene understanding and proactive safety behaviors in shared human-robot spaces. This framework could serve as a foundation for future systems that make context-driven safety decisions, provide real-time alerts, or autonomously assist users in avoiding or mitigating hazards within home environments.

This paper presents a standing support mobility robot "Moby" developed to enhance independence and safety for elderly individuals during daily activities such as toilet transfers. Unlike conventional seated mobility aids, the robot maintains users in an upright posture, reducing physical strain, supporting natural social interaction at eye level, and fostering a greater sense of self-efficacy. Moby offers a novel alternative by functioning both passively and with mobility support, enabling users to perform daily tasks more independently. Its main advantages include ease of use, lightweight design, comfort, versatility, and effective sit-to-stand assistance. The robot leverages the Robot Operating System (ROS) for seamless control, featuring manual and autonomous operation modes. A custom control system enables safe and intuitive interaction, while the integration with NAV2 and LiDAR allows for robust navigation capabilities. This paper reviews existing mobility solutions and compares them to Moby, details the robot’s design, and presents objective and subjective experimental results using the NASA-TLX method and time comparisons to other methods to validate our design criteria and demonstrate the advantages of our contribution.Video: https://bit.ly/moby-robot

This research unveils a novel Multi-Critic Reinforcement Learning framework designed to navigate the multifaceted challenges associated with multi-phased garment handling tasks, notably marked by persistent contact and erratic deformations between textiles and solid bodies. These tasks, ubiquitous in domestic and industrial environments, encompass activities such as dressing, fabric printing, and pressing, and are complicated by the unpredictability of textile states and the intricacy of devising control strategies. Our reinforcement learning model combines multiple time-sequenced Critic networks with traditional Deep Deterministic Policy Gradient (DDPG) techniques, thereby equipping the system to adapt to the diverse effects of fabric distortions throughout various stages. The effectiveness of this approach is demonstrated through a multi-phase pre-printing operation and further validated by real-world implementations, showing significant improvements in coverage and a substantial reduction in wrinkle formation, with its versatility further confirmed by a complex vertical dressing task. We anticipate future applications of this framework in a range of complex problems, not just garment handling. The model used in this paper can be found at https://github.com/jkk5454/multiddpg.git.

Following an accident or motor impairment from illness, individuals often experience reduced mobility. When lower limb function is affected, individuals may lose the ability to walk and rely on a wheelchair. Despite maintaining upper limb mobility, emotional and societal factors may reduce motivation to use them. The Volting project aims to address this by developing a wheelchair with improved mobility to help users achieve their maximum potential. To overcome the limitations of traditional wheelchair controls, a device called WISP was developed, allowing control of Volting through trunk movements. This not only frees the upper limbs but also encourages users to engage their bodies in mobility. Initial experiments with a professional wheelchair dancer showed rapid adaptation to WISP usage. However, gradual implementation is recommended for non-athletic wheelchair users due to the risk of injury from unfamiliar movements. Therefore, we present a training system for WISP utilization, combining a virtual environment with haptic feedback to aid learning and adjust difficulty levels. Preliminary results demonstrate significant improvements in task completion time, collisions, and spatial errors after three sessions in our virtual environment. Additionally, trunk movements decreased, indicating more efficient adaptation to WISP use. As the next step, we plan to conduct trials with individuals with disabilities in our virtual training system, followed by integrating WISP with Volting to explore enhanced mobility.

Recent advancements in medical science and technology have led to a remarkable increase in the lifespan of the global elderly population. However, this demographic often struggles with mobility issues, leading to a sedentary lifestyle fueled by concerns over their physical capabilities. Traditional treadmill gait training, although beneficial, often becomes monotonous and lacks the real-world feedback necessary for engaging and effective rehabilitation. Addressing this gap, research into virtual walking systems utilizing avatar robots has gained traction. Despite the progress, several challenges remain where the systems prioritize visual feedback without considering the crucial need for alerting users to potential dangers and obstacles. This lack of comprehensive environmental awareness and feedback undermines both user engagement and safety. To address this problem, this paper proposes an algorithm that employs B-splines for precise free space detection, integrated with a safety stop mechanism for an avatar robot. This novel approach enhances user awareness of their surroundings through a sophisticated Graphic User Interface (GUI) that leverages Augmented Reality (AR) technology. By superimposing free space boundaries and warning messages directly onto a real-time camera feed, the system provides an intuitive and immersive navigation aid. The efficacy of our proposed GUI was rigorously tested across a series of realistic scenarios, comparing teleoperation control performance with and without the augmented interface. Our findings reveal that our GUI markedly enhances user safety and navigational effectiveness, fostering a deeper understanding of and interaction with the surrounding environment, thereby redefining user experience in virtual mobility assistance.

The ongoing COVID-19 pandemic has enforced governments across the world to impose social restrictions on the movement of people and confined them to their homes to avoid the spread of the disease. This not only forbids them from leaving their homes but also greatly reduces their physical activities. This situation has brought attention to virtual technologies such as virtual tours or telepresence robots. While these technologies allow people to remotely participate in activities, it does not address the problem of reduction in physical activities due to the pandemic. In this paper, we propose a telepresence robotic system driven by the user's gait to provide an immersive virtual walking experience in remote locations. To this end, we developed a control interface consisting of an automated treadmill that adjusts its speed to the user's pace automatically. This interface is used to control an avatar robot that sends a 360-degree live image back to the user for visual feedback. We conducted an evaluation experiment to compare the experience using the proposed system in two different conditions to that of regular walking. The results indicated that the proposed system gives an immersive and realistic virtual walking experience while demanding physical effort from the user.

Certain wheeled mobile robots e.g., electric wheelchairs, can operate through indirect joystick controls from users. Correct steering angle becomes essential when the user should determine the vehicle direction and velocity, in particular for differential wheeled vehicles since the vehicle velocity and direction are controlled with only two actuating wheels. This problem gets more challenging when complex curves should be realized by the user. A novel assistive controller with safety constraints is needed to address these problems. Also, the classic control methods mostly require the desired states beforehand which completely contradicts human's spontaneous decisions on the desired location to go. In this work, we develop a novel assistive control strategy based on differential geometry relying on only joystick inputs and vehicle states where the controller does not require any desired states. We begin with explaining the vehicle kinematics and our designed Darboux frame kinematics on a contact point of a virtual wheel and plane. Next, the geometric controller using the Darboux frame kinematics is designed for having smooth trajectories under certain safety constraints. We experiment our approach with different participants and evaluate its performance in various routes.

Robotic automation is steadily growing in different industries around the world. However, in some industries, such as garment manufacturing, most tasks are still predominantly manual, due to the flexible nature of clothes. Garment and clothes are easily deformed when some force is applied, so it is difficult for robots to handle them while predicting their deformation. Our general research goal is to realize flexible cloth handling using robots to automate different tasks in the garment manufacturing industry. We draw inspiration from the actions that humans perform when manipulating clothes and emulate them using a robotic system. In this paper, we developed a robot hand with a camera at the finger, to obtain local information of the contact between the garment and the robot hand, in order to achieve garment handling tasks. Specifically, we focus on the pinch and slide motion that humans perform when straightening a piece of cloth. We selected a specific task to be automated and proposed three manipulation strategies to approach the garment using visual information from the finger camera that enabled the system to perform the task consistently. We carried out two validation experiments to demonstrate the effectiveness of the proposed methods, and an application experiment where we evaluate their applicability to a specific task.

Quantifying the safety of the human body ori-entation is an important issue in human-robot interaction. Knowing the changing physical constraints on human motion can improve inspection of safe human motions and bring essential information about stability and normality of human body orientations with real-time risk assessment. Also, this information can be used in cooperative robots and monitoring systems to evaluate and interact in the environment more freely. Furthermore, the workspace area can be more deterministic with the known physical characteristics of safety. Based on this motivation, we propose a novel predictive safety model (PSM) that relies on the information of an inertial measurement unit on the human chest. The PSM encompasses a 3-Dofs spring-damper pendulum model that predicts human motion based on a safe motion dataset. The estimated safe orientation of humans is obtained by integrating a safety dataset and an elastic spring-damper model in a way that the proposed approach can realize complex motions at different safety levels. We did experiments in a real-world scenario to verify our novel proposed model. This novel approach can be used in different guidance/assistive robots and health monitoring systems to support and evaluate the human condition, particularly elders.

For the visually impaired people, some outdoor activities like running or soccer are difficult, due to not being able to clearly see the environment. Recently, multiple researchers have contributed to help the visually impaired people run outdoors using robotic systems with different types of feedback, such as auditory feedback and haptic feedback. They discovered that using robotic systems can be an effective way to guide visually impaired people while exercising outdoors. In this paper, we propose a method to guide the visually impaired people to do sports outside using a robotic system with haptic feedback, and we evaluate the feasibility of the proposed system through experiments with blindfolded users running outdoors. In the running guidance task, the position of the runner is determined from the visual feed of a drone, and haptic feedback produced on the users’ left lower leg is used to convey to the runner the directions in which to move to remain on a specific path. Additionally, we compared the performance of users under different haptic feedback modalities in the running task. The three compared modalities are: producing vibration only during the swing phase, only during stance phase or producing vibration continuously. The experimental results for a running task showed that our system enabled users to remain inside a specified track 93% of the total running time, while the ratio decreased to 79%, 77%, and 61% when receiving vibrations during only swing phase, during only stance phase, and without using any feedback respectively. We also observed users felt safer while running blindfolded by using the proposed method.

The users impairments are one of the most important factors for how a robotic mobility aid device is used. However, this has not been addressed in existing solutions. In this paper, we propose using information about the users’ disabilities and impairments to create a navigation prioritization layer for solving multi-robot navigation situations. To deal with the deep subjectivity inherent to assigning these priorities, we propose using human computation to create a navigation solution that will be aligned with humans’ personal value systems, increasing the perceived fairness and trustworthiness of the system. This paper covers the background, methodology, initial experiments and discusses the results, limitations, and future potential of the proposed approach.

This paper investigates the potential of applying the study of Human-Robot Interaction (HRI) via a "Social System Design" approach to legal issues. A problem when considering AI legislation is that many existing laws were written before the development of AI technologies. To address this issue, we propose examining the effectiveness of laws through the Social System Design approach. Specifically, we will use the General Data Protection Regulation (GDPR) to analyze if any legal gaps emerge when it is applied to social robots. To do so we will employ HRI experiments.

Ahstract- In this study, we propose a development and formation control of a passive mobile robot equipped only with servo brakes and no motors. The developed passive mobile robot can move forward by utilizing an external pulling force, and steers itself by controlling the servo brakes attached to each wheel. Systems composed of multiple mobile robots are very effective at exploring vast areas. However the coordination and simultaneous control of several robots utilizing simple information is a difficult task. Therefore we propose a leader follower architecture composed of multiple passive follower robots tethered to one active leader. In this paper, we first introduce the developed passive mobile robot. Then, we analyze the fundamental control method of this passive mobile robot from the perspective of the feasible braking control region, which considers the slip of the passive robot and the limitation of the external pulling force from the active leader. Lastly, a control law for the servo brakes attached to each wheel is proposed, followed by a feasibility study to determine whether the passive followers can stay in formation by controlling the servo brakes with the proposed control law.

Wire-driven haptic devices can easily achieve highspeed operation because of the low inertia of light and thin wires. Therefore, it is expected to be widely used as a motion support system in fields such as sports training. However, usually these wires are driven by controlling each wire's tension using servo motors, which raises concerns about the safety in human-robot interaction. Thus, we propose to support the user by controlling servo brakes instead of motors, which can ensure safety. In this paper, we introduce a passive wire-driven system without any motors for realistic motion support in sports training. The system can measure the user motion and support the user while following a target form by a novel passive control method considering the orientation as well as the position using 7 wires' lengths and the brake tensions. We also conduct error evaluation experiments and show that a tennis beginner using this system can accurately follow the target form.

Various assistive machines have been developed to prevent falling accidents of the elderly. In order to achieve advanced support using robot technology, it is important to acquire data or real-time state estimation of user's various motions. However, a lot of expensive and sophisticated sensors utilized to estimate user's state accurately are difficult to use in general households or institutions. In this article, we propose a method to estimate the user's state utilizing a few inexpensive and simple sensors. We focused on CoG (Center of Gravity) to estimate user's state, but when utilizing less sensors than required to calculate the human link model parameters, the position of CoG is underspecified. Then we considered the range of value of unknown parameters to calculate candidates of CoG. The range of CoG candidates can become narrow enough to estimate human state in real-time by properly selecting and placing the sensors. Therefore, the evaluation of CoG candidates allows us to determine where and which sensors to set when designing assistive robots. We firstly selected some sensors which can be generally found on assistive machines, and we created sets of measurements using the number of unknown parameters. From the result of the experiment using a motion capture system, we confirmed that the range of the candidates was considerably narrow when using some of the created measurement sets. We validated the proposed method to estimate user's CoG candidates by actually placing the sensors according to the designed measurement sets and confirmed that the CoG candidates corresponded to those obtained using the motion capture system.

This study analyzed the precision grip force for the underactuated gripper for power and precision grasp (uGRIPP). uGRIPP is a robot hand developed for dual arm manipulation. It can grasp objects through power and precision grips. For a more detailed analysis of the performance on the grip force and control of the grip force, a relationship was derived between the grip and actuation forces by using an analytical method based on the principle of virtual power. Finally, theoretical values of the grip force were calculated according to the analysis, and the actual grip force was measured experimentally. The experimental results show the validity of the analysis.

Cycling wheelchair was developed for the way of the lower-limb-disabled individuals moving. User can move by pedaling and easily realize free locomotion although they have handicaps. When they use the cycling wheelchair in outdoors, it is necessary to solve the problem of upward slope and downward slope. In this study, we develop a new cycling wheelchair as the system realizing enough aid without motor assist in the way of the safety. We attach CVT (Continuously Variable Transmission) and servo brake on this cycling wheelchair and propose their control methods. By controlling CVT, we can maintain the state of pedaling easily, climb up the slope easily and increase the speed. Also, we realize gravity compensation by controlling servo brake, we can pedal at down slope like a horizontal road. We performed experiment and illustrate the validity of the proposed method.

In this paper we present a wearable Haptic Feedback Device to convey intuitive motion direction to the user through haptic feedback based on vibrotactile illusions. Vibrotactile illusions occur on the skin when two or more vibrotactile actuators in proximity are actuated in coordinated sequence, causing the user to feel combined sensations, instead of separate ones. By combining these illusions we can produce various sensation patterns that are discernible by the user, thus allowing to convey different information with each pattern. A method to provide information about direction through vibrotactile illusions is introduced on this paper. This method uses a grid of vibrotactile actuators around the arm actuated in coordination. The sensation felt on the skin is consistent with the desired direction of motion, so the desired motion can be intuitively understood. We show that the users can recognize the conveyed direction, and implemented a proof of concept of the proposed method to guide users' elbow flexion/extension motion.

The cycling wheelchair is a new type of mobility aid for lower-limb-disabled individuals. Patients can drive the cycling wheelchair by pressing the front pedals with their lower limbs. The device enables patients to effectively rehabilitate their disabled legs and partake in outdoor activities. However, lower-limb-disabled individuals cannot move both legs with equal ease. Typical hemiplegia patients can voluntarily move their healthy leg, but not their disabled leg. Consequently, some of these individuals pedal the cycling wheelchair mainly with their healthy leg, leading to overuse of the limb during their daily activities. This study proposes a pedaling assistive control method that adjusts the different capabilities of the healthy and disabled legs of hemiplegia patients. The proposed control method was applied to a cycling wheelchair with a servo motor for power assist. In experiments, the proposed method reduced the work required for pedaling in two common environments; a planar floor and an upward inclined surface.

In this paper, we propose a novel robot hand called uGRIPP (Underactuated Gripper for Power and Precision Grasp) which has underactuated fingers for dual-arm manipulation tasks. A newly designed underactuated linkage enables the robot hand to achieve not only an adaptive grasp and a pinch grasp, but also manipulation by a palm of the hand. We introduce performance of the proposed linkage by a static analysis. A prototype of the robot hand which has the proposed linkage as fingers was developed. We conducted handling experiments by using the robot hand.

In this paper, we propose a method to assess an extent of anomaly state of human using a walker-type support system. The elderly and the handicapped people use the walker-type support system to keep their balance and support their weight. Although the walker-type support system is easy to move based on the applied force of the user, several accidents such as falling and colliding with the obstacle have been reported. The anomaly state that causes a severe injury of the user should be detected before accident and the walker-type support system should prevent such accidents. In this paper, we focus on assessing the extent of the anomaly state of the user based on the statistical analysis of the applied force of the user. This research models the applied force of the user in real time by using the Gaussian Mixture Model (GMM), and we determine each parameter of GMM statistically. In addition, we assess the extent of the anomaly state of the user by using the Hellinger score, which can compare the data set of the normal state with that of anomaly state. The proposed method is applied to developed walker-type support system with simple force sensor, and we conduct the experiments in the several walking states and the environmental conditions.

In this study, we present a new type of wheelchair called the cycling wheelchair, in which the user moves the wheelchair by pedaling with his/her legs and changes direction using a steering handle. This wheelchair has great potential not only as an effective rehabilitation device but also as a mobility assistive device. However, the commercially available model has several hardware limitations that affect the steering operation. In this paper, we discuss these hardware limitations before presenting methods for improving steering maneuverability. Furthermore, we propose power steering and force display controls based on environmental information. From the perspective of safety, we employ servo brakes to control the cycling wheelchair, and the assistive functions are realized based on the feasible braking control region. The proposed control methods are experimentally applied to a newly developed cycling wheelchair with servo brakes, and the results illustrate the validity of the control methods.

Since the cycling wheelchair was introduced in the 2000s, we have focused on alleviating the over-use of healthy limbs that presents a problem to users. To this end, we have been developing assistance control for everyday users of cycling wheelchairs. In our previous research, we found that user load varies in different environments. Traveling resistance compensation control proved successful in counteracting in a range of environments. In the user-load investigation on cycling wheelchairs, the crank torque generated by pedaling was observed to be problematic for hemiplegic patients, who must pedal mainly with their healthy side. Futhermore, for patients able to bend one leg only, because the opposite limb is stiffened at the knee joint or physically absent, the cycling wheelchair is difficult to maneuver. This paper focuses on the crank torque during one-leg-pedaling and proposes a new assistance control.

In recent years, robots working in human living space with human-robot interactions are actively studied. To these robots, it is important to perform environmental cognition not only building environment map for autonomous motion of the robots but also estimating presences of human around the robots. In this study, by utilizing human state estimation function and SLAM based mapping technology, a concept and architecture of Human Motion Map by representing human behavior in the human living space as a hybrid map system are proposed. Beyond the conventional map which represents the existence of wall and objects, Human Motion Map represents not only the existence of humans in a particular location but also motion distributions. With recent improvements of the cloud computing technology, Human Motion Map can be accumulated as a kind of big data while measurements of robots are performed continuingly while it is moving around. In this paper, we propose a motion feature classification algorithm for clustering human motions geographically. Some experiment result of basic motion feature extraction, geographical clustering, and human motion behavior analyzing are provided for illustrating the validity of proposed algorithm.

In this paper, we propose a method to estimate the geometrical relationships between servo-brake-controlled caster units arbitrarily located on a moving base. The method utilizes only the velocity information of each caster unit and recursively estimates the pose of the caster units by the extended Kalman filter. In the state estimation problem, the estimation performance depends on the quality of the input signals. The input signals must contain sufficiently rich information to appropriately estimate the states. Since the system controlled by servo brakes is driven by a user-applied force, the user can arbitrarily select the input signals of velocity information. Therefore, we also suggest a simple pattern that enables users to provide sufficiently rich information for relationship estimates. Finally, the proposed method is validated in a computer simulation and an experiment using a mobile robot platform equipped with double-wheel caster units.

In this study, we propose a cycling wheelchair that assists the movement of patients with impairment of lower extremities. The wheelchair is a pedal-driven system, similar to a bicycle, moved by the pedaling force of the patient's legs. Although the lower extremities of patients are impaired, they can use both legs to smoothly rotate the pedal. However, there are several barriers to use the cycling wheelchair in an outdoor environment such as steep slopes, steps, and obstacles. In this study, we develop a cycling wheelchair controlled by a regenerative brake system. The braking control provides several assistive functions including velocity control, gravity compensation, and step/obstacle avoidance. The regenerative brake system can also charge a battery during the braking control. However, in situations such as steep-slope climbing and emergency stopping, the regenerative brake cannot generate the required force/moment and an active control is required. In these situations, the control mode is altered from braking to active, and the assistive functions are invoked using the energy charged by the braking control. For safety reasons, we propose a passive motion control method of the cycling wheelchair, even if the wheelchair operates under active control. The proposed cycling wheelchair is validated in a series of experiments in this study.

In this study, we propose a steering control method for a cycling wheelchair. The commercially available cycling wheelchair is a pedal-driven system that is similar to a bicycle, and patients with impairment of their lower extremities can move the wheelchair based on the pedaling force if they can slightly move their legs by themselves. The user can also change the wheelchair direction using the steering handle. However, right and left turns are perceived differently and a large steering torque is required while operating the steering handle because of hardware problems associated with the cycling wheelchair. To overcome this problem, we propose a new hardware solution and a method for steering motion control using servo brakes for the cycling wheelchair. The proposed method is applied to the developed cycling wheelchair, and the experimental results illustrate the validity of the system.

In this study, we propose a robot hand referred to as iGRIPP 4 (Integrated Gripper for Power and Precision Grasp 4), which has suction mechanism at each fingertip. This robot hand can grasp various objects steadily and achieve dexterous manipulations with a simple mechanism. The iGRIPP 4 has three fingers and two servomotors which are designed to grasp objects in power grasp and precision grasp. The suction mechanism at the fingertips enhances grasp stability, and enables the hand to hold large objects. In addition, the combination of the grasp mechanism and the suction system make it possible to perform some dexterous manipulations. Examples of the manipulations include the picking up a thin object and the packaging an object in a bag. These manipulations generally require hands with many degrees of freedom and intricate control. In this paper, the mechanism of the iGRIPP 4 is presented, and the two dexterous manipulations that can be done with this robot hand are described.

Many one-degree-of-freedom (1-DOF) grippers have been used in factories. This paper focuses on the design of the 1-DOF parts handling device for picking up small objects robustly and agilely and realizing assembly tasks. In our conventional research, we proposed a concept for the handling device, which cages an object without letting the object escape from its tips before closing them completely and then grasps the object robustly at a unique position of the tips. In this paper, we propose a method for designing the shape of the device's tips by considering not only the caging and self-alignment of the object but also the gear assembly task. We also develop the robust and agile pick-up device (RAPiD) with tips designed by the new method and present experimental results that illustrate the ability of RAPiD to handle and assemble gears.

This article describes the concept of a novel car transportation system including two mobile robots with a lift mechanism for single wheel. The system lifts only two drive wheels of a front-wheel-drive vehicle or a rear-wheel-drive vehicle, and transports them. However, the system has nonholonomic constraints because all wheels of a vehicle are not lifted by the system. This article also describes a motion control method and a vehicle's wheelbase estimate algorithm for the proposed system in order to maneuver the vehicle. The motion control method is based on control theory for a three-wheeled cycle system. On the other hand, the vehicle's wheelbase estimate algorithm includes impedance control, and the system estimates the vehicle's wheelbase from constraint forces during transporting the vehicle. Finally, two experiments show that the proposed system can maneuver the vehicle.

In this paper, we propose a passive wire-type motion support system to guide a human hand through the use of servo brakes. This system is intrinsically safe because servo brakes cannot generate a driving force to control the system. On the other hand, this system may not generate sufficient force to guide the human hand along the desired path because of the use of servo brakes. To resolve this problem, the standard approach would be to increase the number of brake units to generate the desired force. However, the large number of wires attached to each brake unit might restrict the user's motions, and there would be a potential for injury if the wires entwined around the user. Therefore, in order to safely guide the user's motion, we need to decrease the number of brake units having wires. In this paper, we consider a feasible braking force region of the wire-type passive system with multiple brake units and discuss the number of brake units required to guide the user's motion appropriately. We develop the wire-type motion support system that uses servo brakes and conduct path-following experiments considering table tennis as an example of sports training. In addition, we present experimental results that show the passive system with a small number of brake units can guide the user's hand along the desired path.

In this study, we consider the development of a device for handling small parts for automatic product assembly in factories. Many robotic hands and one-degree-of-freedom grippers have been proposed as grasping parts; here, we focus on the shape of the tips of a handling device for picking up small parts robustly and agilely. In this research, we propose a concept for a handling device for picking up small round parts. In this concept, the handling device cages an object without letting the object escape from its tips before closing them completely and then grasps the object robustly at a unique position of the tips. Using this caging and self-alignment concept, the handling device can pick up objects robustly and agilely. In this paper, we focus on a method for designing the shape of the device's tips using the concept of caging and self alignment of objects. We also develop the robust and agile pick up device (RAPiD) with tips designed by the new method and present experimental results that illustrate the validity of the concept and the ability of RAPiD to handle small parts.

To assist human motion in the fields of rehabilitation and sports training, we propose a passive motion support system consisting of wires with servo brakes and a control method to guide the human hand. However, passive systems sometimes cannot generate enough force to guide the human hand along the desired path because the servo brakes cannot generate a driving force and the system does not have enough brake units to generate the desired force. In this paper, we theoretically consider the feasible braking force region of a passive system with multiple brake units and discuss the number of brake units required to generate the desired force appropriately. We also develop a system based on our analysis of the feasible braking force and conduct path-following experiments. The experimental results illustrate the validity of a passive motion support system consisting of wires with servo brakes.

The goal of this study is to develop a control method for levitation stabilization of an aerodynamic levitated train named the "Aero-Train," which is a high-speed, high efficiency train system. The levitation in this system occurs because of the wing-in-ground effect that acts on a U-shaped guideway. In order to achieve the goal of this study, a small experimental prototype and a control method for stabilization along the Z axis and about the roll and pitch axes were developed, as described in this paper. The effectiveness of the developed control method is confirmed by experimental results.

This paper proposes a new car transportation system, iCART II (intelligent Cooperative Autonomous Robot Transporters - type II), based on “a-robot-for-a-wheel” concept. A prototype system, MRWheel (a Mobile Robot for a Wheel), is designed and downsized less than the half of the conventional robot used in iCART (intelligent Cooperative Autonomous Robot Transporters). In general, it is very difficult for mobile robots such as MRWheel to move to desired positions without motion errors caused by slipping, etc. Therefore we propose a decentralized control algorithm for car transportation in coordination by using a leader-follower type multiple robot system. The proposed algorithm enables the followers to estimate and reduce the motion errors and then enables the robots to transport a car to a desired position, even if the motion errors occur. In addition, we discuss how the external force applied to each robot during transporting a car, such as an inertial and friction force, is shared among the robots, and we propose a model-based external force estimation and compensation method. The proposed control algorithm is applied to the system, and the results of car transportation experiment confirm its validity.

We introduce passive mobile robots consisting of various wheels; omnidirectional wheels or one-wheel casters, which are controlled by servo brakes. These robots can realize several functions, such as path tracking, gravity compensation on a slope, and collision avoidance function, by controlling only the servo brakes. They employ passive dynamics with respect to the force applied by a human. In this paper, we derive and analyze a feasible braking force/moment that is necessary for controlling the robot with servo brakes. We reveal the advantages and disadvantages of the feasible braking force/moment of each robot developed by us. In addition, we propose a new passive type double wheel caster unit, called PDC, on the basis of the analysis. We develop a prototype PDC called PDC-P1. Finally, we handle a long object by two PDC-P1s actually, and realize the path tracking function as example to confirm its validity.

This paper proposes a distributed motion control algorithm of multiple passive mobile robots for handling an object in cooperation with a human. The driving force of the passive mobile robot is an actual force applied by the human and the servo brakes attached to the wheels control its motion. Different from the active-type robot with servo motors, the passive robot has the control limitation based on the brake constraint. In this paper, we consider a feasible region for the brake control of the robot and propose a distributed motion control algorithm of the multiple passive mobile robots for handling a large object along the desired path, in which each robot compensates the control input required by other robots which do not generate it because of the brake constraint. We apply the proposed algorithm to two passive mobile robots called PRP experimentally and they realize an object handling along the desired path accurately.

In this paper, we introduce a passive haptic device which consists of wires with servo brakes and its control method for physical support of human being. Since servo brakes control a point constrained by wires, this passive system is intrinsically safe and has a wide operating range. We especially develop a motion support system controlled on plane and conduct a path following experiment for illustrating a possibility of the passive haptic device with wires. We also analyze the system's characteristics by calculating the feasible braking force, and then improve the operating range of the system based on the analysis. Experimental results on path following function illustrate the validity of the system and its control method.

We introduce a passive mobile robot called CPRP (Caster-type Passive Robot Porter). This robot consists of multiple casters with servo brakes and a controller. C-PRP employs passive dynamics with respect to the force applied by a human. Its appropriate motion is controlled using the servo brakes. In this paper, we derive and analyze a feasible braking force/moment that can be applied to the robot on the basis of the characteristics of the servo brakes. In addition, we propose a motion control algorithm for C-PRP based on the analysis of this feasible braking force/moment. This algorithm is independent of the number of casters. The proposed algorithm is applied to a four-wheeled C-PRP and the experimental results confirm its validity.

The car transportation system, which termed as iCART (intelligent cooperative autonomous robot transporters), is developed for handling the car in the narrow space, substituting the parking and unmanning the transportation of cars. iCART is composed of two robots and these robots transport the car in coordination based on a leader-follower type distributed motion control algorithm. To avoid damaging the surface of the car, tires of the car are putted on, not grasped by, the end-effector of robots. Thus, when force/moment applied to the car by robots becomes large, the slip at the contact of the robot with the car occurs. Due to the slip, the relative position between robots is changed. In a conventional algorithm, the relative position is used for the control. Thus, after the contact of the robot with the car slips, occasionally, robots could not coordinate. For overcoming this problem, the motion control algorithm based on the caster-like motion is applied to the car transportation system iCART in this paper. Since this algorithm does not use the relative position information, the system becomes robust against the slip at the contact of the robot with the car. The proposed motion control algorithm is applied to iCART and experimental result illustrates the validity of the proposed algorithm.

In this paper, we introduce a passive mobile robot called PRP (Passive Robot Porter), which has passive dynamics with respect to an applied force and its appropriate motion is controlled based on the servo brakes. In this paper, we especially focus on a motion control algorithm of multiple passive mobile robots for handling a large object in cooperation with a human. By controlling each passive mobile robot in the decentralized way, we realize collision avoidance function and path following function of the object to improve the maneuverability for the human operator. The proposed algorithms applied to two PRPs actually, and experimental results illustrate the validity of the proposed algorithms.

In this paper, we introduce a passive mobile robot with casters developed based on the concept of passive robotics. This mobile robot consists of two casters with servo brakes, one passive rigid wheel and a controller. We can manipulate the robot by controlling external force/moment applied by a human based on the control of the servo brakes attached to the casters. We consider the characteristics of the servo brakes and control the brake torque of each caster based on the braking force and moment constraint so that several motion functions of the robot are realized based on the applied force. This allows the robot to track a path without using servo motors. The motion control based on the environment information is also realized, so that we could avoid the collision with obstacles. These functions are implemented to the robot experimentally and experimental results illustrate the validity of the robot system and its control method.

Object manipulation problem by multiple cooperating mobile robots using the concept of object closure is discussed in the paper. It is the condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance during the transportation. We proposed the concept of dynamic object closure for achieving object caging task that robots team is able to cage a moving object after a predefined time interval. In the paper, a method planning caging path and by using random caging formation path determination algorithm (RCFP) is proposed for achieving dynamic object closure. Some planning results are presented for illustrating the validity of the proposed algorithm.

In this paper, we propose an intelligent cane developed based on passive robotics concept for supporting the elderly and the disabled persons who have difficulty walking. The intelligent passive cane (IP Cane) is controlled by servo brakes attached to the wheels and intrinsically safe for humans, because it cannot move unintentionally, i.e., it has no driving actuators. In addition, the IP cane provides many kinds of functions by appropriately controlling the torque of wheels with servo brakes. In this paper, we propose an environmentally adaptive motion control algorithm that provides path following function, and a human adaptive motion control algorithm that changes motion characteristic of IP cane to adapt to user difficulty and states.

When we consider a coordination of multiple mobile robots, it is difficult to know the geometric relations among them. Errors in position and orientation of each robot detected by dead reckoning system are inevitable because of the slippage between wheels and the ground. To overcome these problems, in this article, we introduce a caster-like dynamics for controlling the multiple mobile robots in coordination. By using the caster-like dynamics, multiple mobile robots could handle a single object without using the geometric relations among them and the shape of the object. The effectiveness of the caster-like dynamics is illustrated through the video in which several types mobile robots handle a single object in coordination.

In this paper, we introduce a passive mobile robot called PRP (Passive Robot Porter), which has passive dynamics with respect to an applied force and its appropriate motion is controlled based on the servo brakes. This paper especially focuses on a motion control algorithm of multiple passive mobile robots for handling a single object in cooperation with a human. By controlling each passive mobile robot in the decentralized way, we realize several kinds of motion characteristics of the object to improve the maneuverability for the human operator. By changing the apparent dynamics of the representative point of the object and its position, we realize an anisotropic apparent motion characteristic of the handling object and the obstacle avoidance function as examples. The proposed motion control algorithms are implemented to two PRPs actually, and experimental results illustrate the validity of the proposed algorithms.

In this paper, we propose a new car transportation system referred to as iCART(intelligent cooperative autonomous robot transporters). This system consists of two robots for the car transportation. Each robot is controlled by using a decentralized control algorithm for transporting the car in coordination. A trajectory for transporting the car is given to one of robots, and another robot estimates the trajectory through the interaction force between two robots. This car transportation system could transport any size of cars, and is available for any kinds of car transportation tasks such as parking, ballet parking, tow away service, and the transportation of cars at a factory, ferry, parking area, etc. The proposed car transportation system are developed and the control algorithm is experimentally applied to them. The experimental results illustrate the validity of the proposed system.

In this paper, we describe a method for controlling wearable walking support system which is referred to as wearable walking helper. In this method, the support moment for the userpsilas knee joint is calculated with an approximated human model and a part of it is supported by the prismatic actuator of Wearable Walking Helper. In the conventional control algorithm, we only considered to support the user to walk on the level ground and assumed that horizontal components of Ground Reaction Force (GRF) could be neglected. In this paper, we especially focus on the support of walking on slope, and estimate slope angle based on sensor signals from accelerometer and force sensors. By using the estimated slope angle, horizontal components of GRF are calculated and we apply it to the calculation method using the human model. The proposed method is applied to Wearable Walking Helper and the experimental results illustrate the validity of it.

As aging progresses, fall accident of the person using the walker is an acute problem. It is necessary to know the situation of the userpsilas fall to prevent it. In this paper, we propose a method for estimating the userpsilas fall by modeling of the user in real time as a solid body link model, and pay attention to the center of gravity of the model. We also propose a method for controlling a passive intelligent walker to prevent the userpsilas fall according to the support polygon and the walking characteristic of the user. We experimented with passive intelligent walker in which we implement the proposed fall prevention control and show the effectiveness of the proposal method.

In this paper, we propose a method for supporting a walking of a human by using wearable walking support system called Wearable Walking Helper. In this method, the support moment for the knee joint of the user is calculated by the human model and a part of it is supported by the actuator of the Wearable Walking Helper. In the conventional method we proposed so far, we only consider the stance phase of the gait which requires a large moment of the knee joint in walking for supporting the weight of the user. In this paper, we especially focus on the support of the swing phase of the gait which requires a moment of knee joint for supporting not only the weight of the leg but also the weight of the Wearable Walking Helper itself. For realizing the swing phase support, we measure an inclination of the upper body of the user with respect to the vertical direction by using the accelerometer and apply it to the calculation method using human model for deriving the support moment of the knee joint. The proposed method is applied to the Wearable Walking Helper experimentally and the experimental results illustrate the validity of the proposed method.

This paper proposes a control approach for an active robotic walking support system based on environment feedback. The support system is controlled using imposed apparent dynamics and its parameters are varied by the environment information. The environment information will not cause any motion but will only change the characteristics or maneuverability of the support system. This approach leads to a passive behavior for an active walking support system. In addition, the stability of the support system based on the apparent dynamics is also discussed. This is important as a guideline on what parameters to vary that will not cause instability to the system. Experimental results are presented to show the validity of the control algorithm with environment feedback.

A dance partner robot has been developed as an example of platforms for realizing the effective human-robot coordination with physical interactions. This robot could dance together with a human by estimating the next step intended by the human. If the robot would mistake the step estimation, the human-robot coordination could not be continued. In this paper, an error recovery method for step selections, which changes robot's behavior according to human's behavior, is designed using hidden Markov models. Experimental results illustrate the validity of the proposed method.

In this paper, we propose a concept on realizing impedance-based motion control of passive type robots for transporting a single object in coordination with a human operator. In this research, we developed a prototype of passive type robot referred to as passive robot porter or PRP, which consists of three omni-directional wheels with MR Brakes, and on-board computer system. We analyze the singularity of PRP braking torques, and control the brake torque of each wheel based on the brake force/moment constraint so that impedance characteristics is realized on PRP with human's pushing. This allows a PRP to track a 2D path which includes motion perpendicular to human's pushing direction without using servo motors, and multi-PRPs to work cooperatively on handling a single object with orientation control for avoiding collision with obstacles. Experimental results are shown to illustrate the validity of the proposed concept.

This paper proposes a motion control algorithm for an active type of robotic mobility aid based on passive behavior concept. Passive behavior is an important characteristic of a system that provides mobility to elderly or person with walking disability. It allows the user to control the system based on intention. Passive behavior is implemented using imposed desired dynamics, which represents the actual behavior of passive system. This approach uses user intention represented by applied force/torque to derive the mobility aid desired motion. In addition, a guideline in parameter selection of the desired dynamics is also presented. This guideline is used to ensure the stability of the active robotic mobility aid with passive behavior. Experimental results are presented to show the validity of the proposed control method.

In this paper, we introduce a passive mobile robot called PRP to realize a transportation of an object in cooperation with a human which is developed based on a concept of passive robotics. The PRP (Passive Robot Porter) consists of three omni-directional wheels with servo brakes and a controller. It can manipulate an object by controlling an external force/moment applied by a human based on the control of the servo brakes. Therefore, if the required external force and moment for realizing the manipulation of the object are become large, the burden of the human would increase and the controllability of the robot would decrease. To overcome these problems, in this paper, we propose a system in which the PRP carries the object through a free joint. By using the free joint, the orientation of the object is changed by the intentional moment applied by the human and the robot only controls the position of the object based on the servo brake control, so that the required intentional force for transporting the object could reduce compared to the previous version of the PRP without using free joint. Additionally, in this paper, we propose a motion control algorithm for the PRP with free joint and illustrate the validity of the proposed system and its control algorithm through the experiments of the object handling.

In this paper, we propose a coordinated motion control algorithm of multiple mobile manipulators handling a single object without using force/torque sensors. In this control algorithm, each mobile manipulator is controlled as if its grasping point has an impedance dynamics by using the real dynamics of the manipulator instead of force/torque sensors. These mobile manipulators handle a single object in coordination using the leader-follower type control algorithm based on the impedance dynamics. Then, the effect of parameter identification errors is discussed and a method to reduce it is proposed. The proposed control algorithm is experimentally applied to two mobile manipulators, and the experimental results illustrate the validity of the proposed control algorithm.

This paper discusses advanced human-robot coordination systems. In order to realize the coordination, robots have to behave as not only followers but also leaders when they execute tasks with humans. As an example of the advanced human-robot coordination systems, a male-type dance partner robot is developed, which behaves as a male dancer and executes ballroom dances with a human. In ballroom dances, a male dancer leads a female dancer, and selects the next step based on the information such as the relative position between themselves and other dance couples, their positions in the dance floor, and so on. This paper addresses the step selection problems, which contains collision avoidances with other dance couples. Hidden Markov models are used to estimate their dance step trajectories. Experiments and simulations are performed to illustrate the validity of the proposed method.

As an example of platforms for realizing the effective human-robot coordination with physical interactions, a dance partner robot has been developed, which could dance together with a human by estimating the next dance step intended by the human. Generating robot’s active motion so as to be adapted to its user could be one of essential functions in the next generation robotic technology. This paper proposes the cooperative motion generation method for the robot, which is implemented by adjusting length of dance step stride based on physical interaction between the human and the robot. Experimental results illustrate the validity of the proposed method.

This paper proposes a new control approach for an active (motorized) robotic walking support system based on passive behavior concept. The control approach aims to enhance the interaction between the support system and the user. The passive behavior of a support system allows the user to safely interact with the system since it removes the system's capability to move when there is no user's intention. This passive behavior is realized using imposed apparent dynamics, which uses the user's intention represented by the applied force/torque to derive the system's desired motion. The control approach is extended into a user-oriented motion control algorithm to adapt user's controlling characteristics. This is implemented by varying the point of application of the apparent dynamics. The control approach is further extended to use environment information and realize environment feedback concept. This is implemented by varying the parameters of the apparent dynamics based on environment data. Experimental results are presented to show the validity of the proposed control approach.

We propose a new intelligent walker based on passive robotics that assists the elderly, handicapped people, and the blind who have difficulty in walking. We developed a prototype of the robot technology walker (RT walker), a passive intelligent walker that uses servo brakes. The RT walker consists of a support frame, two casters, two wheels equipped with servo brakes, and it has passive dynamics that change with respect to applied force/moment. This system is intrinsically safe for humans, as it cannot move unintentionally, i.e., it has no driving actuators. In addition, the RT walker provides a number of navigational features, including good maneuverability, by appropriately controlling the torque of servo brakes based on RT. We propose a human adaptive motion control algorithm that changes the apparent dynamics to adapt to user difficulties, and an environmentally adaptive motion control algorithm, which incorporates environmental information to provide obstacle/step avoidance and gravity compensation functions. The proposed control algorithms are experimentally applied to the RT walker to test their validity.

In this paper, we introduce a passive-type walker using servo brakes referred to as RT Walker. RT Walker realizes several functions such as obstacles/steps avoidance function, path following function, gravity compensation function, variable motion characteristics function, etc., by controlling only servo brakes without using servo motors. These passive-type systems are dependable for using practically in real world environment, because of the passive dynamics with respect to the applied force/moment, simple structure, lightweight, and so on. However, the most serious problem of them is the falling accident of user, because the passive-type systems are lightweight and move easily based on the small force/moment applied by the user unintentionally. In this paper, we pay attention to a method for estimating the human state during the usage of the walker and propose a motion control algorithm for realizing a fall-prevention function based on its human state. We also implement the proposed control methods in RT Walker experimentally and illustrate the validity of them

This paper presents an approach in assisting a sit-to-stand movement using a robotic walking support system. In general, robotic walking support system is used to provide walking stability. We will extend its function to assist a user in executing a sit-to-stand movement. The first approach would be called passive support. In this approach, the support system would be stationary as the user execute the sit-to-stand movement. The knee torque would be determined and this would be compared to a sit-to-stand movement without support. The second approach would be called active support and the knee torque would be supported. A motion control algorithm would be proposed such that the support system will move based on the supporting torque. The actual experimentation on both approaches in assisting a sit-to-stand movement will be presented. The experimental result on active support shows the validity of the proposed motion control algorithm

In this paper, we present a method for estimating the user states during the usage of the walker, which support the walking of the user based on the physical interaction between the user and the walker. We also propose a method for renewing these estimation parameters changed by the users and the environmental conditions. The proposed methods are experimentally implemented in RT Walker, which is passive-type intelligent walker. The experimental results illustrate that the proposed methods could estimate the user states during the usage of the walker and the parameters for estimating the user states are changed based on the several kinds of the conditions such as physical size, daily conditions and operational characteristics of the users, environmental conditions, and so on

We have proposed a real-time self-collision avoidance motion generation method for the manipulator of the robot used for human-robot cooperation. In this method, we represent the robots' body by using elastic elements referred to as "RoBE (representation of body by elastic elements)". The self-collision avoidance could be realized based on a virtual reaction force generated by the contacts between the elastic elements before the actual self-collision of the robot. In this paper, we expand this method to control not only robots' manipulator, but also its mobile base. Furthermore, we focus on the range of the joint movement of the robot, and propose the self-collision avoidance motion generation method considering it. Because of these, the self-collision motions which could deal with task/environmental constraints could be generated on the robot cooperating with a human. The proposed method is implemented in the planar 4-DOF mobile manipulator, and computer simulations are done for illustrating the validity of it

We have proposed a dance partner robot, which has been developed as a platform for realizing the effective human-robot coordination with physical interactions. In the previous research, we have improved an estimation system for dance steps, which estimates the next dance step intended by a human. Although estimating the intended step is important for realizing the human-robot coordination, the cases that the estimation is failed and that the robot selects an incorrect step are not considered. Such cases have to be discussed carefully for realizing the effective human-robot coordination. In this paper, a method for error detections of dance step selections are proposed, which is designed using hidden Markov models. Experimental results illustrate the validity of the proposed method

In this paper, we discuss the manipulation of planar objects by multiple cooperating mobile robots using the concept of object closure. It is the condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. We proposed the concept of dynamic object closure for achieving object caging task that robots team is able to cage a moving object after a predefined time interval. A random caging formation testing algorithm (RCFT) is proposed for checking dynamic object closure condition. Some simulation results are presented for illustrating the validity of the proposed algorithm

This paper proposes a new control approach for a robotic walking support system to adapt a user's controlling characteristic. The control approach will be implemented by changing the kinematic structure of the robotic walking support system based on a variable center of rotation. This new control approach aims to help users who have difficulties in controlling their walking support system. In this study, we have a training stage to evaluate and adapt user's controlling characteristics. This will be implemented by allowing the user to follow some training paths. In the event a large path error occurs, a learning algorithm will vary the center of rotation of the support system until the user can successfully follow the training path. The relationship between the user intent in the form of applied force/torque and the new center of rotation will be taken by considering several training paths. This relationship will be used in actual control of the robotic walking support system. Experimentation and evaluation are presented to show the validity of the proposed control algorithm

In this paper, we propose a motion control algorithm of a passive-type walking support system based on environment information. The passive-type walking support system we developed consists of a support frame, two casters, and two wheels with servo brakes. This system has a passive dynamics with respect to the force/moment applied to it, because it does not have any actuators for driving it, so that this system is intrinsically safe for using it based on the physical interaction between the system and the human being. In this research, we control the motion of the passive walker by adjusting the brake torque of each wheel based on the environment information, so that a user could avoid the collision with obstacles, prevent missing his/her step, and compensate the gravity of the system as if the user could use it safely on any roads such as the road with steep sloop. The proposed control algorithms are applied to passive-type walker referred to as RT Walker experimentally, and we show that RT Walker can be utilized successfully in environments such as the stairs, obstacles, and slops.

This paper propose a new control algorithm for a robotic walker based on augmented variable center of rotation (COR) to adapt to user's controlling characteristics. The new CORs are taken from environment-based training. This is done by allowing the user to use the robotic walker from a start point to a goal point in a training environment and path following algorithm is employed. The user's intention represented by applied force/torque is logged during training. The logged data is segmented to correspond to the straight and curve segments in the training environment. This data is used to regenerate the path of the robotic walker. The error between the regenerated and the desired path is taken and in case a large path error exists, an optimization program is used to change the COR until the sum of the square of the path error is minimized. This approach refers to an offline COR determination. A variable COR controller as a function of applied torque is designed based on the new CORs. This is augmented and used in the actual control of the robotic walker. The proposed control algorithm was experimentally implemented and results show its validity.

We have proposed a real-time self-collision avoidance control method for the robot which is used for human-robot cooperation. In this method, we represent the body of the robot by using elastic elements referred to as "RoBE (representation of body by elastic elements)". The self-collision avoidance motion could be realized based on a reaction force generated by the contacts between the elastic elements before the actual self-collision of the robot. In this paper, especially, we consider task constraints and environmental constraints during the self-collision avoidance motion, and propose two priority functions for robots to realize the several kinds of tasks in an environment based on the force/moment applied by a human. By using this control algorithm, we could apply the proposed control algorithm to any robot systems used for human-robot cooperation. The proposed motion control algorithm is implemented in a human-friendly robot, referred to as "MR Helper", and experiments are done for illustrating the validity of the proposed self-collision avoidance motion.

We have proposed a dance partner robot, which has been developed as a platform for realizing the effective human-robot coordination with physical interactions. In this paper, especially, we improve an estimation system for dance steps, which estimates a next dance step intended by a human. For estimating the dance step, time series data of force/moment applied by a human to the robot are utilized. The time series data of force/moment measured during dancing by a human and the robot include the uncertainty such as time-lag and variations for each repeated trial, because a human can not always apply the same force/moment to the robot exactly. In order to treat the time series data including such uncertainty, hidden Markov models are utilized for designing the dance step estimation system. With the proposed system, the robot estimates a next dance step based on human intention successfully.

We address the manipulation of planar objects by multiple cooperating mobile robots using the concept of object closure, a condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. In this paper, we develop a distributed testing algorithm of object caging by multiple cooperative robots. By implementation of a complete testing based on the sufficient and necessary condition of object closure, the proposed algorithm works efficiently even for case to cage an irregular object.

In this paper, we propose a new algorithm which shows a buried landmine clearly in an underground image captured by a ground penetrating radar (GPR). By using GPR, we could extract the buried object signals from a raw underground data of GPR. In addition, we could create a high resolution underground image which focuses on buried objects. The extraction of buried object signals from raw GPR data is achieved by using two methods which are a feature extraction processing method of underground image and a ground adaptive manipulation method which manipulates the sensor head of GPR along a ground surface. Moreover, we propose novel synthetic aperture radar processing, which could be applied to an uneven ground surface of a minefield, for detecting the landmine clearly. The high resolution underground image is obtained by the proposed synthetic aperture radar processing which is referred to as ground adaptive synthetic aperture radar algorithm. We developed a landmine detection robot, in which the proposed methods were implemented. To evaluate the proposed methods, experiments concerning landmine detection are done and experimental results illustrate the validity of the system.

We propose a leader-follower type motion control algorithm of multiple mobile manipulators handling a single object in coordination. In this algorithm, the representative point of each robot is controlled as if it has a caster-like dynamics in 3-D space, and each robot handles a single object in coordination with other robots without using the geometric relations among the robots. The proposed control algorithm is experimentally applied to multiple mobile manipulators, and the validity of the proposed control algorithm is illustrated by the experimental results.

This paper addresses the problem of multi-robots object transportation by using the concept of Object Closure. In contrast to Form or Force Closure which is used in the research of grasping, Object Closure is a condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. Once Object Closure is achieved, the robots can cooperatively drag or flow the trapped object to the desired goal. In this paper, we address the concept CC-Closure Object and testing algorithms using properties of CC-Closure Object. Also the scaling and control problem of caging formation is addressed and two algorithms to realize two-effectors pushing on fixed caging formation control is proposed.

This paper propose a new control algorithm for a robotic walking support system, which varies the kinematic structure of the system to adapt users' walking or controlling disability. Elderly who suffers from deficiencies in motor skills cannot control or steer their walkers properly. Since the applied torque is highly correlated to the heading angle of the walker, torque transformation is needed to properly steer the walker. The variation of kinematic structure would be implemented by varying the center of rotation (COR) and as a result the torque of the system is changed. In order to model the users' walking or controlling disability, the user would be asked to follow a desired path. Using a learning algorithm, errors between the desired and actual path would be used to determine the new COR. The proposed control algorithm was experimentally implemented and the result shows its validity.

We propose a concept of a new walking support system based on passive robotics for supporting elderly people, handicapped people, and blind people who have difficulties in walking, and develop a prototype of new walking support system referred to as RT Walker. RT Walker consists of a support frame, two casters, and two wheels with servo brakes, and has a passive dynamics with respect to the force/moment applied to it, because it does not have any actuators for driving it RT Walker would be a system with many functions and a good maneuverability by controlling the brake torques of servo brakes appropriately based on robot technologies (RT). In this paper, we propose motion control algorithms of RT Walker for changing its apparent dynamics to adapt to the difficulties of the user, and for moving based on the information of an environment.

In this paper, we address a decentralized control method for object transportation in coordination by using a leader-follower type multiple robot system, which consist of a pushing leader, a leader robot without grasping mechanisms, and multiple follower robots. During the object transportation, a desired trajectory is given to the leader robot only, and follower robots estimate the trajectory of the leader based on force/moment from the object. In the proposed system, a variable internal force is introduced to each robot's controller in decentralized style to let the follower's estimator work on not only the pushing but also the "pulling" case that the leader needs to slow down or move back the object. Finally, a multiple robot system including three omni-directional mobile robots is presented and experiment results are shown to illustrate the concept of the proposed control algorithm.

In this paper, we propose a decentralized control algorithm of multiple mobile manipulators for handling a single object in cooperation with a human. In this algorithm, a grasping point of each mobile manipulator is controlled as if it has a caster-like dynamics referred to as virtual 3-D caster, and each mobile manipulator could handle the object based on an intentional force/moment applied by a human. In addition, the coordination among multiple mobile manipulators was realized without using the geometric relations among robots. The proposed control algorithm is experimentally applied to two mobile manipulators referred to as DR HelperII and experimental results illustrate the validity of the proposed control algorithm.

This paper addresses the problem of multi-robots object transportation by using the concept of object closure. Once object closure is achieved, the robots can cooperatively drag or flow the trapped object to the desired goal. In this paper, we address the concept CC-closure object used for efficient testing of object closure. Properties of the CC-closure object and testing algorithm are described. Finally, an example of object closure constructed from both bodies and hands of mobile-manipulators is discussed and an experiment is presented for illustrating the proposed concept.

We propose a dance partner robot referred to as Ms DanceR (Mobile Smart Dance Robot), which has been developed as platform for realizing the effective human-robot coordination with physical interaction. Ms DanceR consists of an omni-directional mobile base and a Body Force Sensor, which is a force/torque sensor installed between the mobile base and the body of the robot. A human could dance a ballroom dance together with Ms DanceR based on a control architecture referred to as "CAST" (Control Architecture based-on Step Transition), which was designed according to features of ballroom dances.

This paper addresses the problem of multi-robots object transportation by using the concept of object closure. In contrast to form or force closure which is used in the research of grasping, object closure is a condition under which the object is trapped so that there is no feasible path for the object from the given position to any position that is beyond a specified threshold distance. Once object closure is achieved, the robots can cooperatively drag or flow the trapped object to the desired goal. In this paper, we address the concept CC-closure object, which is used for efficient testing of object closure. Testing algorithms using these properties is described. Also object closure margin is defined and the scaling and control problem of the caging formation is addressed. Finally, an example of object closure constructed from both bodies and hands of mobile-manipulators, which have different shape and size, is discussed and experiments are presented for illustrating the proposed concept.

We propose a decentralized motion control algorithm of multiple mobile robots transporting a single object in cooperation with a human based on a path generated from an environment. Each mobile robot is controlled as if it had caster-like dynamics around a representative point attached to the object and its representative point moves along the path based on the intentional force applied by a human. The proposed decentralized control algorithm is experimentally applied to three omni-directional mobile robots referred to as DR Helper. Experimental results illustrate the validity of the proposed control algorithm.

In this paper, we propose a decentralized control algorithm of multiple mobile manipulators handling a single object in coordination. In this algorithm, the grasping point of each robot is controlled as if it has a caster-like dynamics in 3-D space, and each robot handles a single object in coordination with other robots without using the geometric relations among the robots. The proposed control algorithm is experimentally applied to three mobile manipulators, and the validity of the proposed control algorithm is illustrated by the experimental results.

We propose a decentralized motion control algorithm of multiple mobile robots transporting a single object in cooperation with a human based on a path generated from an environment. Each mobile robot is controlled as if it has a wheel with a free rotational joint and moves along the path based on the intentional force applied by a human. The proposed decentralized control algorithm is experimentally applied to the omni-directional mobile robots referred to as DR Helpers. Experimental results illustrate the validity of the proposed control algorithm.

We propose a decentralized control system of multiple mobile robots transporting a single object in coordination without using force/torque sensors. In this system, each robot is controlled as if it has a specified impedance dynamics without using a force/torque sensor. The robots transport an object in coordination using a leader-follower type control algorithm. The effect of parameter identification errors is discussed and a method to reduce it is proposed. The proposed control algorithm is experimentally applied to two mobile robots, and the experimental results illustrate the validity of the proposed control algorithm.

We propose a decentralized control algorithm of multiple robot helpers, called DR Helpers, which have been developed for manipulating a large object in cooperation with humans. In this algorithm, each robot is controlled as if it has a caster-like dynamics around a representative point attached to the object, and manipulation of a large or long object in cooperation with a human can be realized easily. The proposed control algorithm is experimentally applied to two DR Helpers and experimental results illustrate the validity of the proposed control algorithm.

We propose a motion control algorithm for the dual arm-mobile robot MR Helper, for handling an object in cooperation with a human based on impedance control. The algorithm specifies the apparent impedance of the manipulated object directly with respect to the world frame. It also specifies the apparent impedance of the mobile base relative to the object frame, so as not to influence the motion of the object. The control algorithm is implemented in MR Helper and experimental results obtained illustrate the validity of the proposed algorithm.

In this paper, we propose distributed robot helpers (DR helpers) and a decentralized control algorithm for them to transport a single object in cooperation with a human/humans. The DR helper consists of an omni-directional mobile base, a six-axis body force sensor, a folk lift, and an onboard controller. Each robot is controlled as if it has a caster-like mechanism. The adaptive dual caster action is proposed to improve the maneuverability of the system. Multiple DR helpers could transport a single object in cooperation with a human based on the operator's intentional force/moment. Experiments using multiple DR helpers will illustrate the validity of the proposed control system.

We propose a decentralized control algorithm of multiple mobile robots transporting a single object in coordination. In this algorithm, each robot is controlled as if it has a caster-like mechanism and transportation of a single object by multiple mobile robots is realized without using the geometric relations among robots. The proposed control algorithm is experimentally applied to two mobile robots. Experimental results illustrate the validity of the proposed control algorithm.

In, this paper, we discuss a problem relating to the force/moment transformation for the handling of a large object by multiple mobile robots in coordination. We propose a control algorithm using geometrical constraints among the grasping points and the representative point of the object, which reduce the effect of noise amplified by force/moment transformation. We extend this algorithm to the decentralized control algorithm of multiple robots handling an object in coordination. The proposed control algorithm is experimentally applied to the mobile robots. Experimental results illustrate the validity of the proposed control algorithm.

In this paper, we propose a new mobile robot architecture with a body force sensor. The body force sensor is the force/torque sensor which is located between the drive mechanism and the body of the mobile robot. The use of the body force sensor almost realizes the collocation of sensors and actuators, and makes the whole body of the mobile robot sensitive to external force/moment. Decentralized motion control algorithm for handling a single object by multiple robots in coordination is implemented in each mobile robot and stable handling of an object is realized by multiple mobile robots with the body force sensor. Experimental results illustrate the validity of the proposed architecture.