The robotic pick-and-place system is applied widely in many fields such as assembly, packaging, bin-picking, and sorting. In this paper, we present a deep learning and analytical-based method for generating antipodal grasping multi-modality in highly cluttered scenes. Our method takes advantage of three types of grasp poses to deal with the complexity of environment and achieves efficient computation time for real applications. A new synthetic training datasets are generated in Isaac Sim including approximately 35000 RGB-D images and an automatic labeling algorithm is developed. We utilize convolutional neural networks (CNNs) for predicting antipodal grasping parameters on objects and a filtering algorithm to avoid collisions and calculate grasp’s depth simultaneously. Our approach processes the entire task in approximately 0.2 seconds, achieving a success rate of over 96% and more than 98% collision-free grasps in cluttered scenes. The method was verified by experiments with RB10 robot arm, two-fingers grippers, depth camera L515, and several objects in different scenes. The article shows a simple, effective, and highly applicable approach in real environments. The real experimental video of our method is shown athttps://www.youtube.com/watch?v=GvJZxUyQr3w. Note to Practitioners—The robotic pick-and-place task is fundamental to the progress of automation. This article presents a novel method for efficiently picking objects from complex environments characterized by obstacles, overlaps, and a diversity of objects. These scenarios pose challenges in approaching objects and avoiding collisions. Our method combines learning and analytical approaches, demonstrating high performance in terms of accuracy, generalization across various scenes and grippers, and rapid computation, with the entire process taking approximately 0.2 seconds. These advancements are validated through a series of real robotic grasping experiments and comparisons with state-of-the-art methods. We believe that our method represents a significant contribution to the field of automation science and holds promise for real-world applications.

The significance of physical human-robot interaction (pHRI) with collaborative robots in the industry is growing steadily. Within this domain, an admittance controller is crucial for enabling robots to follow or assist human intentions. However, a persistent challenge with admittance controllers is ensuring their passivity. Various strategies have been developed to address this issue by adjusting the control signals derived from the admittance model. While these strategies achieve passivity, they often inadvertently impact collaborative performance, preventing the system from accurately aligning with the intended dynamics. Accordingly, this paper introduces an adaptive hierarchical control approach for redundant robots to handle this problem. This approach diverts non-passive power into the null space without diminishing the robot’s responsiveness to human input. Implementing this null-space controller involves the dynamic adjustment of compliance control error, ensuring joint limit avoidance while facilitating integration with energy tanks for enhanced reliability. Moreover, the method enables the calculation of adaptive error gain in a closed form, simplifying its real-time application. Experimental validation with a 7-DOF manipulator showed a reduction of non-passive energy from 1.61 J to 0.12 J without compromising task performance.

Super-coiled polymer (SCP) artificial muscles have many interesting properties that show potentials for making high performance bionic devices. To realize human-like robotic devices from this type of actuator, it is important for the SCP driven mechanisms to achieve human-like performance, such as compliant behaviors through antagonistic mechanisms. This paper presents the simultaneous position-stiffness control of an antagonistic joint driven by hybrid twisted-coiled polymer actuation bundles made from Spandex and nylon fibers, which is a common human compliant behavior. Based on a linear model of the system, which is identified and verified experimentally, a controller based on model predictive control (MPC) is designed. The MPC performance is enhanced by the incorporation of time delay estimation to estimate model variations and external disturbances. The controlled system is verified through simulations and experiments. The results show the controller's ability to control the joint angle with the highest position error of 0.6 degrees while changing joint stiffness, verified with step command and sinusoidal reference with composite frequencies of 0.01Hz to 0.1Hz.

This paper introduces a force-controllable quadruped robot system consists of twelve Actuator Modules embedded a novel Capacitive-type Joint Torque Sensor (CJTS) which is accurate (0.05 Nm), robust to impact, and easy to manufacture at low cost. The Actuator Module with CJTS shows accurate joint torque controllability in range of ±70 Nm (90 % settling time 0.04 s). The leg made by the three Actuator Modules is capable of generating forces in the z-axis up to 350 N and shows force control performances with zero-force control and lifting weights in three-dimensional space. To reduce the reflected limb inertia, all the Actuator Modules are located on the body frame and light-weight limbs made of the carbon pipe (3.6 % of total body weight). The introduced robot performed the motion on various terrains with walking/trot gaits.

The Elastic Inflatable Actuators (EIAs) has several advantages such as the inherent compliance due to the body comprised of a soft materials such as silicone. Among them, the soft fiber reinforced actuator is based on the principle that the expansion of enclosure and constraint of fiber pattern lead to a desired operation. While lots of researches on the actuator has been attributed to linear and bending motions, however, there are only few researches on rotary, or torsional, motions. In this paper, we propose a new actuator that causes azimuthal deformation due to restriction of anisotropically distributed fiber element along the radial direction and expansion of the hyper elastic material. Structure design of the actuator and a fabrication process of the actuator are presented. Subsequently, FEM simulation and experiment are executed to measure rotation angles of the actuators corresponding to the applied pressure.

This paper presents a flexible dual-type proximity sensor forrobotic applications such as human collaborative robots(HCRs) todetect the surroundings. The sensor consists of two parts; sensing transducer and a shielding layer. To amplify the sensing performance, a resonant frequency is formed by an inductive(L-type) electrode and two capacitive(C-type) electrodes, which are placed in coplanar with an LCR circuit. An optimal frequency range is suggested to amplify the proximity detecting performance with a consistent response of impedance change. The developed sensor has a size of 100 x120x2.8 mm3. To obtain the flexibility for various robot surfaces attachment, the electrode layer is made of Flexible Printed (a) Circuit Board(FPCB). Combined with the grounded shielding layer, the sensor can detect objects up to 300 mm in 10 mm resolution when attached to a grounded surface. The sensor is evaluated in diverse circumstances to validity for practical use on robotics.

In this paper, we present a novel framework for quadrupedal stair climbing, which considers force interaction with stairs. For stable and robust climbing, a key issue is to avoid falling down on the stairs. From this point of view, control to minimize rate of change of angular momentum about Center of Mass (CoM) which is produced by ground reaction force (GRF) at contact of robot`s foot is necessary. Using this approach, direct force-based Zero Moment Point (ZMP) for motion planning of the CoM and landing force control are implemented. The direct force-based ZMP method allows the robot to lift its foot with reduced possibility of tilting on the stairs, and the landing force control prevents instant increase of the moment by impact of the GRFs. In addition, terrain recognition to estimate parameters of the stairs and find proper footholds by vision system mounted on the robot is presented. Proposed framework is implemented to quadruped robot, AiDIN-VI, that has torque sensor at each joint, through experiments, capability of ascending several stairs including 3-step stairs which have 21cm height (31% of its maximum leg length) and 26.5° inclination is validated.

This paper presents a 1-link robotic arm that is antagonistically driven by one pair of a high performance super-coiled polymer actuators with an embedded controller. The actuator which is made from Spandex and nylon fibers is low-cost, easy to fabricate and light-weight. Moreover, it can generate large displacement and provide Joule heating capability. The main contribution of the paper is the model-based impedance controller, which enables position control of the antagonistic joint with variable stiffness and damping. The impedance control is a torque-based law, which in turn depends on a proposed backstepping control law to control the force of each actuator. The control system is proved to be stable using dissipativity stability theory and verified through experiments. Experimental results show that our system can track the angular position reference with the worst position error of 0.43deg and root-mean squared error of 0.16deg at steady state for sinusoidal waveform tracking (with the frequency of 0.1Hz), and the worst position error of 0.2deg for set-point regulation.

This study presents a new drone, called S-CLOUD, developed for safe and long flight time. It provides 3-axial (x, y, and z)translational motion and stable hovering for more than an hour after takeoff. S-CLOUD consists of two parts; soft blimp part and driving one. The soft blimp is a center-pierced torus-shaped part filled with Helium gas. Thus, it is safe to fly near people because it is light and soft, and all its rotating parts are at the center of the vehicle, which does not get damaged on collision. The driving part is plugged into the center of the soft blimp and includes the flow control mechanism, which consists of co-axial rotors and 2-axis crossed flaps. It controls the altitude, attitude, and translational movements of the vehicle. Its dynamic and reaction features against disturbances are derived using Newton-Euler formulation, and the simulation results are discussed. Finally, a prototype of S-CLOUD is fabricated and its feasibility is experimentally validated with practical applications.

This paper presents a fabric actuator consisting of ordinary polymer fibers, conductive fibers, and twisted and coiled soft actuators (TCAs). Previous studies have developed a Spandex TCA (STCA) that is driven at a lower temperature than the conventional Nylon TCA and exhibits greater actuation strain. However, no method to drive STCAs via electrical joule-heating has been developed yet. The fabric actuator presented in this paper offers a solution to this problem by employing an STCA multiple fabrication method, a continuous fabrication method, bundling technology, and weaving technology. Two types of samples (cylindrical and planar) are fabricated and their performances are evaluated experimentally. From the actuation test according to the loads, the maximum contraction strain of 34.3% is measured. The repeatability is also verified through 200 cycles of actuation. Using a linearized model, the dynamic performance of the fabric actuator is predicted and compared with experimental results. An actual human arm size mannequin is driven by applying the fabric actuator, and angle control can be achieved with an encoder mounted on the joint. In addition, fabric actuator is weaved to sweater showing the possibility of wearable assistive robot.

From being soft, flexible and producing movement by contracting, soft linear actuators are said to have muscle-like properties. Due to these similarities, they are often called “artificial muscle actuator.” However, the strain produced by these actuators is generally insufficient to be utilized in a large range of applications. Some solutions have been developed, but they sacrifice force to increase the displacement. Meanwhile, the force produced by skeletal muscles increases as it contracts due to its working principle, which is based on the “sliding filament mechanism.” The limitations of soft linear actuators could be overcome by mimicking the contraction process of skeletal muscles. Two types of muscle-inspired robotic joint mechanisms based on the sliding filament mechanism principle are proposed in this work. The mechanisms can be operated using any type of soft linear actuators as well as traditional actuators or motors, and this work realizes the implementation using shape memory alloy wires and 3D printed mechanical parts. The feasibility of both proposed mechanisms, and their capabilities were experimentally verified.

The concept of utilizing the Coandia effect to produce stable flight in saucer type Aerial Vehicles (AV) was first conceived in 1935 by Henri Marie Coanda. Coanda's proposed AV design remained a relatively unexplored curiosity for decades until the recent surge in popularity of small Unmanned Aerial Vehicles (UAV) revitalized interest in the topic. Coandä effect UAV offer some distinct advantages over standard multirotors due to their robust frame design, which offers a unique mix of crash resistance, flight safety, and flight performance making them ideal for Human-Robot Interaction (HRI) applications. While much work has been performed in the area of characterization for Coanda surfaces and improved mechanical design of saucer type UAV, little work has been found in the literature discussing stability and attitude control of the platform. This work seeks to contribute to the study of these drones by introducing an approximate servo mapping for desired control effort of a particular prototype, and an experimental control law implemented within the framework of a modified commercially available flight stack.

Force-sensing system represents one of the vital components of robotic systems for physical interaction performances. This system is facilitated by the force controllable actuators. However, to make a force controllable actuator, it is still a challenging subject for the majority of the robotic system. This paper proposes a novel POWERPACK unit integrated a torque sensor, a harmonic drive and a motor for enabling the force control. The torque sensing element is based on the capacitance sensing to achieve a compact and a simple structure. In this research, reveals the practical details of the POWERPACK and evaluates the performance of the actuator unit.

In the physical human-robot interaction system, improving transparency performance which allows humans to move as if there is no robot is a challenging topic. In general physical human-robot interaction, the multiaxial force sensor is used to control the robot. However the signal measured from the force sensor involves not only the force applied to the robot by the human motion intention but also the influence of the natural force feedback between the robot and the human hand due to the motion of the robot. Therefore, in order to improve the transparency performance, it is necessary to consider the dynamics of the human hand as well as the dynamics of the robot. In this paper, an novel algorithm to improve transparency performance is proposed. The proposed algorithm uses only the multiaxial force sensor and compensates the natural force feedback by using the human hand impedance and further improves the transparency performance which has a limitation adjusting admittance parameters. The validity of the proposed algorithm is described through the system model analysis and the experiment using the hydraulic upper limb exoskeleton.

Intrinsic problems for legged robots are `low energy efficiency' and `slow speed'. In this paper, we introduce a possible solution achieved through biological observations and developed a robotic leg applying the proposed method. The proposed robotic leg, AiDIN-IV Leg (Artificial DIgitigrade for Natural environment version IV) has high torque density actuators(τpeak= 152Nm, 127rpm), high fidelity force/torque controllability(under 5% torque error) and large energy storing capacity(18J) suitable for high-speed running robot. As a core part, Series Elastic Actuator(SEA), achieve large passive deflection angle(47.6°) for storing the energy as much as possible(maximally 37.9J), and constant joint stiffness coefficient. Additionally, oscillation compensator for rejecting the oscillation of SEA and Harmonic Drive efficiency compensator are introduced and successfully tested in the proposed robotic leg.

Various control strategies using trajectory planning, object recognition and learning are researched for avoiding obstacles when legged robot is walking. In this paper, designed trajectory by using Non Uniform Basis Spline (NUBS) curve and control strategy, by using proposed trajectory, to effectively overcome obstacles are presented. The trajectory designed by NUBS curve has several advantages: 1) local modification, 2) tracking velocity control for each domain, and 3) low degree trajectory with a large number of control points. The robot gets remarkable effectiveness when these advantages are used to generate the trajectory for walking and overcoming obstacles. By implementation of the proposed control strategy, quadruped robot can walk over obstacles while keeping its gait, speed and balance without collision although adjusting relatively preferable state which is more suitable position or posture of the walking robot shortly before encountering obstacles is not required. The proposed trajectory and control strategy are discussed, and performance is validated through experimental evaluations.

This paper presents a hexapod crawling robot which has bioinspired design and locomotion posture from the insects. The robot, called S-Hex II, is an upgraded version of the different printable monolithic hexapod robot which is named as S-Hex I. The S-Hex II is studied for the project of developing mesoscale walking robots actuated by the soft dielectric elastomer actuators. In comparison with the S-Hex I, the S-Hex II owns smaller dimension, lighter weight, and significantly faster walking speed. We improve and increase the total number of degree-of-freedom (DOF) of the soft dielectric elastomer actuators (DEAs) from three, used in the S-Hex I, up to five, employed in the S-Hex II, and that provides the promising versatile locomotion ability to the S-Hex II robot. This robot has successfully demonstrated the back and forth ambulation on flat surfaces using the alternating tripod gait with the walking speed of 52 mm/s (approximately 0.35 body-lengths per second) at 7 Hz of actuation frequency.

In running, legged animals take advantages of their flexible bodies to increase their locomotion performance, resulting in superior mobility and fast motions. Previous works on quadruped robots mostly used the simplified model with massless legs. However, in reality, a leg consists of two or three segments with mass and inertia. We study herein the bounding of quadruped robots with a model closer to a real animal, i.e., a model having articulated legs with joints with stiffness and damping properties, and a passive spinal joint, to obtain an insight into the robot's dynamic behaviors. The effects of spine flexibility were investigated on quadrupedal bounding gait by changing dynamic properties and hardware parameters and then comparing the performance of models with and without a spinal joint. The model comparisons revealed that body flexibility significantly increased stride length and strongly affected the dynamic of the body and the energy efficiency.

This paper demonstrates a new haptic display based on soft actuator and soft sensor. The device consists of an array rigid coupling actuator and an array tactile sensor which configured sensor located on the top of actuator. The actuator includes a frame with rigid coupling made by silicone and a dielectric elastomer actuator(DEA). The movement of the DEA is transferred to touch pad via rigid coupling. Thus, it provides a soft, comport touch feeling and eliminates the danger of applying high voltage to the human skin. The actuator can work at a wide range frequency of 0–150 Hz and produce sufficient force of 50 mN over the human hand threshold. The tactile sensor can measure the pressure, locate the objects and send the feedback signals to control the actuator. In this work, a 8×12 haptic tactile display is made with high resolution. In addition, the high voltage signal processing also developed to generate variable 0–3.5 kV, and can control individual cell by using the dynamic scanning actuation algorithm. Then, it can display any shape such as a circle, a smile/sad face, a star, etc. In the future, we will build the “emotion touch pad” system which can transfer a person's emotion to another one via internet.

This paper presents a highly sensitive dual mode tactile and proximity sensor for robotic applications that uses Carbon Microcoils (CMCs). The sensor consists of multiple electrode layers printed on a Flexible Printed Circuit Board (FPCB) and a dielectric substrate into which the CMCs are dispersed. The dielectric layer is simply put on the top of the FPCB. Thus, the sensor provides ease of fabrication and robustness against repetitive external contacts because the dielectric layer protects the electrodes. The electrical properties of the sensor are changed when an object approaches or touches the sensor. The sensor uses a capacitive sensing mode for tactile sensing and an inductive sensing mode for proximity sensing. CMCs amplify the change of the sensor signal because of electrical impedance formed by the CMCs, and thus, the sensitivity of the sensor increases. We fabricate the prptotype sensor with the dimensions of 30 × 30 × 0.6 mm3, and with 3 mm spatial-resolution. The sensor detects the applied pressure up to 330 kPa and the distance of an object as much as 150 mm away.

This paper aims to develop novel surgical forceps integrated with a three-axis force sensor for robot-assisted minimally invasive surgery (RMIS). To detect accurate force sensing, a force sensing system is integrated to a gripper of a surgical instrument. At the gripper side, two possible locations are considered, and the sensing system is installed to the distal region of the gripper, which gives major advantages such as the gripper's minimization, palpation function, and multi-axis force sensing. Based on the capacitive-type sensing method, the sensor enables the direct measurement of the three-axis force applied to surgical gripper tip. The sensorized gripper is simply designed at a low cost, composed of only four mechanical parts, and, the forceps including two grippers are installed to an instrument that is able to conduct a grasping motion. Therefore, it is used to evaluate the performance of the force sensing system. The sensorized forceps are experimentally validated by using a commercial sensor in an experimental set-up.

This paper presents a grasping force-feedback user interface (GFUI) which transfers the accurate kinesthetic force detected during robot-assisted minimally invasive surgery (RMIS) to a user, and allows the users to perform grasping motions with articulation and intuition. Using the GFUI, a developed robot hardware (S-surge) is controlled, and the force data measured from the robot are reflected to the GFUI. To evaluate the effect of grasping force-feedback control using the GFUI, a group of subjects (n=10) participated in a standard peg transfer tasks with and without the feedback control. To conduct the tasks, a developed robot hardware and a commercial haptic device were used which make the entire surgical environment including the GFUI as a master-slave controlled system. As a result, the performance of the GFUI was verified through the conducted tasks using the entire surgical system.

Most legged animals exploit flexible body and supporting muscles to produce power for dynamic behaviors which results in fast locomotion and additional mobility. Previous works have focused on the symmetric flexible body with massless legs associated to the body. However, body bending in animals during running happens prior to the rear side instead of the middle point of body. Therefore, a quadruped model with a passive spinal joint, asymmetric segmented body, actuated hip joints and legs is introduced. By using a numerical return map, a periodic bounding locomotion of the model is found with optimal sets of initial conditions and proper system parameters. Moreover, this paper investigates the effects of spine flexibility in segmented body on quadrupedal bounding gait. The results show that asymmetric segmented body has bigger spine oscillation, shorter stride period and smaller cost of transport, which helps the robot run more efficiently.

Aiming to apply soft actuators in driving a walking robot, the design, fabrication and locomotion of a bio-inspired printable hexapod robot are studied. The robot mimics the insect's design and walking posture by driving six legs with alternating tripod gait which provides its locomotive adaptability on flat terrains. The versatile movements of the robot's leg are achieved by using soft and multiple degree-of-freedom actuators. The actuators are made by dielectric elastomers with a simple mechanism based on antagonistic configuration. By using 3D printing method, the actuator can be embedded into the frame of the robot and a control system is developed. Finally, the robot's locomotion is successfully demonstrated with variable speeds and stride lengths.

This paper presents a mechanism for the robot moving inside of pipelines. The mechanism is composed of the 2-2D differential gear mechanism, the active adhesion mechanism, and the rescue mechanism. The 2-2D differential gear mechanism is designed to be driven with single actuator at any elbow type pipelines without any additional control efforts. The active adhesion mechanism is for providing sufficient adhesion forces of the robot on climbing over the pipelines against the gravity. In addition the rescue mechanism is designed for retrieving the robot safely in emergency situation. In this paper, three proposed mechanisms are explained in details and their effectiveness is experimentally demonstrated.

In this paper, a back-drivable joint mechanism for an in-pipe robot is presented. The joint mechanism consists of 2-pitch and 1-roll joint. The back-drivability of the joint mechanism is realized by using a ball-screw and a steel wire rope. When the in-pipe robot with the back-drivable joint mechanism passes through pipeline elements except the miter and the branch, the control of the joint mechanism is not required. In addition, a rescue mechanism is not needed in case of emergency such as the loss of power, communication and control. Besides, the 2-pitch joint of this joint module assists the in-pipe robot to pass through the miter and the branch safely and quickly. Finally, the performance of back-drivable joint module is experimentally validated.

This paper presents a novel surgical instrument integrated with a four-degree-of-freedom (DOF) force sensor. By adopting the capacitive transduction principle, the sensor enables the direct sensing of normal and shear forces at surgical instrument tips. Thus, three-DOF pulling forces and a single-DOF grasping force can be measured for haptic feedback control of robotic minimally invasive surgery systems. The sensor consists of four capacitive transducers, and all the transducers including analog signal processing units are embedded in small surgical instrument tips. The four-DOF force sensing is enabled thanks to the four capacitive transducers by using the force transformation method. In this study, the instrument is designed and manufactured to be adaptable to the open-source surgical robot platform, called Raven-II. In addition, the sensing system is experimentally validated through its application to the Raven-II by using a reference force sensor.

This paper introduces a novel robot which is able to climb hanger cables of long span suspension bridges. The robot has been developed for inspection purpose, and it can help us remotely inspect the state of cables by using cameras and Non-Destructive Testing (NDT) devices. The robot consists of two traction modules, two sub modules, and an adhesion mechanism. The unique design of the traction module ensures the stable movement of the robot on the twisted surface of the hanger cable. In this paper, we describe the structure and environmental situation of hanger cables and the mechanisms of the robot. Also, the results of experiments in the indoor and outdoor environments are included.

In this work, we present a flying saucer, a kind of unmanned aerial vehicle(UAV), lifted based on Coandă effect. Coandă effect is an interesting fluid dynamic phenomenon that the interaction between the flow and curved surfaces produce attraction, which results in the lifting of the object. The flying saucer adopting Coandă effect is easy to hover while keeping its posture stable, and vertical take-off and landing(VTOL) is possible. Its design procedures via optimization and manufacturing procedures are explained in details, and the preliminary tests in the indoor and outdoor are successfully demonstrated.

To deploy an untethered robot inside pipelines without any external assistance, it is prerequisite to recognize the pipeline elements such as straight pipeline, elbow, T-branch, and miter. This paper presents a method of recognizing pipeline elements using PSD(Position Sensitive Device) sensors. It is easy to implement, but help us collect accurate information necessary for navigating inside pipelines without heavy computation. The method is composed of three parts, which is the method for distinguishing T-branch and miter, searching the direction in T-branch and elbow, and determining the types of pipeline element, respectively. The design for the PSD sensor suite is presented and the algorithm for recognition procedures are addressed. The sensor suite is implemented in an in-pipe robot, called MRINSPECT VI, and its performances are validated.

This paper presents a grasper-integrated force sensor that provides the capability of measuring dual axial forces at the tip of surgical robot for minimally invasive surgery (MIS). On the sensorized forceps, the combination of dual axial forces measured at each side of grasper presents three axial pulling and single axial grasping force sensing, which provide force feedback control using haptic device. It consists of simple structure of triangular prism shape and two capacitive-type pressure sensor cells based on elastomeric polymer which provides the information on normal and shear forces. The sensing principle is to compare the difference between responses of two pressure sensors when the surface of the sensor contacts to the tissue. A sensorized forceps is fabricated by employing the molding method and electronics for signal processing is embedded. Finally, experimental evaluations are performed and its feasibility is validated.

This paper presents a multi-axial force sensing system for haptic feedback of minimally invasive robotic surgery. The system consists of a 3-axial force sensor located on the wrist of surgical grasper and a torque sensor which plays a role of pulley for driving tendons. The 3-axial force sensor measures magnitude and direction of manipulation forces when the grasper grasps and pulls the tissue, while the torque sensor measures grasping force transferred through the driving tendons. The sensors and a grasper mechanism are designed and manufactured. For the calibration and verification of the prototype sensors, a testbed which simulates tissue manipulation is built and experiments are performed to evaluate the sensing system.

In this paper, novel mechanisms for an in-pipe robot are presented. Multi-axial differential gear mechanism is designed to be driven with only single motor at any elbow-pipe without additional control efforts while all three wheels keep driving power. Brake system was added to prevent slip of wheel. Active wall pressing mechanism allows controlling the contact forces. And additional rescue mechanism is designed for emergency situation. Lastly, their effectiveness is experimentally validated.

This paper presents a preliminary design and experimental results of a multi-axial contact force sensor for robotic surgery graspers. The sensor is a thin-film type capacitive one with a multiple cell structure capable of measuring normal and shear forces at contacts simultaneously. The structure of the sensor is determined via numerical optimization for maximizing sensitivity and based on the results, a prototype is fabricated by employing the silk-screening method. The characteristics of the sensor are evaluated with a multi-axial sensor calibration set-up and the sensitivities for two directional shear forces and a normal forces are measured to be 10.1, 10.3 and 6.1%, respectively. In this study, the feasibility of the sensor is confirmed as the proof-of-concept. In our future studies, a miniaturized pair of the proposed sensor will be embedded to a surgery grasper for in vitro validation.

This paper presents a mechanism for an in-pipe robot, called MRINSPECT VI (Multifunctional Robotic crawler for In-pipe inspection VI), which is under development for the inspection of gas pipelines with 150mm inside diameter. The mechanism is composed of multi-axial differential gear mechanism, wall pressing one, and driven by single motor. It is designed to adapt to the varying inside geometries of pipelines such as elbows by modulating the velocities of active wheels mechanically without any control effort. In this paper, the design features of the mechanism are detailed and its effectiveness is experimentally validated.

The differential drive mechanism, which is one of the mechanisms of wheeled mobile robots, is simple and useful for the motion of the mobile robot. The mechanism, however, has typical disadvantages of losing mobility, falling down, etc. when the robot moves over obstacles or uneven terrains. A novel suspension mechanism presented in this paper was designed to help the robot to overcome these problems. In particular, this mechanism is very suitable for a tall robot, which is susceptible to overturning because of the disturbance caused by acceleration, deceleration, and collision. The proposed mechanism called a Multilayered Suspension Mechanism is composed of the effective and well-directed combination of springs and dampers. It is very simple and cost-effective since it has no actuator for suspension. In this paper, mechanical construction and characteristics of the mechanism are described. Then, excellence and performance of the proposed mechanism are demonstrated by simulations and experiments.

In this paper, we present a smart handheld surgical tool with tactile feedback to help microsurgery. This device consists of force sensors attached to the tool tip and tactile displays on the position of the fingerhold. The sensor is capacitive one and measures not only the magnitude of force, but also the direction of force. The sensor can measure 9N of lateral forces along x-y-z direction. The tactile display is based on dielectric elastomer actuators and made up of three rigid coupling tactile display modules. The tactile displays provide stimuli of 170μm displacement and frequency of 10Hz at the surgeons fingertips. We fabricate the device and its performances are experimentally validated.

Recently, Dielectric Elastomer Actuator(DEA) comes to the market successfully by introducing commercial products such as tactile interfaces for mobile applications. As an advanced application, we present a tactile display device actuated with dielectric elastomer actuator(DEA) in this paper. By employing fluid coupling between the touch spot and the actuator, the device ensures the comfort of touch and the safety of operation from the high driving voltage while contacting with the human skin. In addition, it is compatible with SMT(Surface Mount Technology), which can be easily plugged into PCB(Printed Circuit Board)s like semiconductor chips and extend to the arrayed tactile display, easily. In this paper, its working principle is overviewed and the actual design with fabrication procedures are described in details. Finally, a prototype is made and its performance is evaluated experimentally.

This paper presents a simple method to control the motion of a quadruped robot in unknown rough terrains using a full dynamic model. First, using typical stiffness control method, the four legs' behavior is approximated to 3D spring damper systems. By this way, we can easily derive the dynamic equations of motion in Cartesian space. Based on these equations, a control strategy is proposed to obtain the asymptotical stability of the system. In addition, a reflex signal is also introduced to control the rotational disturbance of the robot body. Finally, dynamic simulation of a quadruped walking robot is performed on several unknown rough terrains to verify the proposed method.

This paper presents a comprehensive study on the design and implementation about 2-DOF decoupled kinematic actuator module based on the parallel structure with a high mechanical stiffness. The basic structure of 2-DOF decoupled kinematic actuator module has two motion units. Since one motion unit can be moved in only one direction, various applications are available and it can solve the parasitic motion fundamentally. The two motion units also have fine motion and coarse motion respectively. Besides it can be variously modified based on how the actuators are connected. Then the hardware of 2-DOF decoupled kinematic actuator module is implemented with one actuator and two additional locking devices. And the performance of the hardware will be evaluated by experimental system.

In this paper, we present the autonomous pipeline navigation method of an in-pipe robot, based on the landmark recognition system and 3D orientation sensor. The fittings of pipelines such as elbows and branches can be used as the landmarks. In this paper, we introduce a noise tolerant landmark detection method using a line laser beam projected on the internal surface of the pipeline. Once the line laser is projected on the surface of landmarks, a unique line pattern is generated. By using this line pattern, the robot can easily detect and distinguish these landmarks while recognizing the direction of the pipeline path. Simultaneously, the robot's pose information from the orientation sensor and the driving motor's encoder is continuously recorded and used to reconstruct a map of the pipelines. By using this map and a specific navigation strategy, the robot can navigate in the 3D pipeline autonomously. The effectiveness of the proposed method is validated by experiments using the in-pipe robot called MRINSPECT V.

The curvatures of an object play an important role in the shape reconstruction of that object. In this research, we suggest a method of estimating unknown curvatures using a coarse-resolution force torque sensor. First, a method of estimating unknown curvatures using large motions in terms of rolling and sliding is proposed. Next, a tracking algorithm for an unknown surface based on an inner position loop control algorithm is presented. An application of this method to the finger of a robot hand is also discussed. Finally, the algorithm is verified by simulations and experiments for several cylinders with different radii.

In this paper, we present a global localization and local pose error compensation method in a known structured environment using magnetic landmarks. In previous our research, it was possible to compensate the pose error (xe, ye, qe) of a mobile robot correctly on the surface of structured environment with magnetic landmarks. In this work, we propose a methodology of arranging magnetic landmarks on the map such that properly arranged magnetic patterns ease the global localization of a mobile agent. Among total six patterns of magnetic-bar in square arrangement, five unique landmarks are obtained. Therefore, a heuristic pattern search method is applied to build the virtual map using five landmarks. In order to obtain the global pose information, the robot identifies the pattern of magnets, and obtains the current global pose information by comparing the measured neighboring patterns with the map information that is saved in advance. Experimental results show the effectiveness of the magnetic-pattern landmarks for the global localization and local pose control of a mobile robot.

In this paper we present a robotic actuation system by artificial muscle actuator based on dielectric elastomer. A novel linear actuator called “multi-stacked actuator” is presented, which can be embedded in the phalanges of the finger and ensures a compact design of the overall system. As an exemplary work, a two degree-of-freedom robot finger is developed and its performance is experimentally demonstrated. The proposed system can be extended to the multi-fingered robot hand easily, and applied even for articulated mechanisms such as legged robots etc.

In this paper, we present an autonomous in-pipe robot navigating system using vision-based landmark recognition. We propose to use special features of the pipelines (such as elbows or branches) as landmarks by recognizing the shadows of the elbows and branches. To obtain consistent shadow images, the in-pipe robot equips with specially designed illuminator. By analyzing the shadow, the robot can easily identify these landmarks, detect the direction of the passage, and adaptively traverse through while continuously updating the map. The effectiveness of the proposed method is verified by real experiments using the in-pipe robot MRINSPECT V for inspecting inside of the miniature urban 8-inch gas pipeline structure.

Physical size of semiconductor components has been reduced and device density has become increased especially during for last years. As a result of this the use of various high precision manipulatable robot systems becomes norm in the industry. Normally the high precision robot system consists of precision staging system, small scale end-effector system, and highly sensitive autonomous sensing system. One of the most popular micromanipulation tasks might be handling of micro-scale objects on a surface. Although many functional aspects and constraints should be considered when the system is constructed, a key concern for the system design is level of dexterity of the manipulator especially when size of the objects to be handled and spatial resolution of the manipulator become smaller than micron or nano scale. And stiction effect has appeared since a micro-contact mechanics phenomena affects more primarily than inertial force in the high precision robot system. Thus a theoretical study has to be developed on a micro-contact mechanics phenomena. In this paper, the organized system is equipped with an omnidirectional accessible manipulation system with a new visual feedback system. Thanks to the enhanced dexterity of the system, in this paper, microparticle stiction problems that could happen to most of small object handling also can be resolved.

Improvement of the adaptability of a quadruped robot in rough terrain is studied in this paper. First, the position and posture of the body of the robot are adjusted to maximize the number of choices for foot placement of the next swing leg. The more choices the robot has to select the next suitable foothold, the better it will be to cope with rough terrain. Second, an effective foothold search algorithm is developed. The foothold search algorithm not only tries to find a valid foothold but also tries to maintain high adaptability of the robot. For implementing the algorithm, some new concepts such as potential swing direction, complementary kinematic margin and elliptical set of candidate footholds are also proposed. The effectiveness of this procedure in improving the adaptability of a quadruped robot moving in challenging terrain is verified in both simulation and experiment.

Aiming to real easy application in several quadruped robot platforms, this paper introduces a new method of modeling central pattern generators (CPG) to control quadruped locomotion. Not only can this new model generate all the primary gaits of quadrupeds stably with limit cycle effect, but it also has the ability of tuning the periodic outputs with arbitrary waveforms. The core idea is to combine strong points of two mathematical tools: Fourier series and Recurrent neural networks. In addition, a new biomimetic controller is also introduced using the proposed CPG model and several reflex modules. Finally, dynamic simulations are performed to validate the efficiency of the proposed controller.

The requirement of effective reconstruction of surface texture has been raised by applications concerning interaction with objects; however, the reconstruction of precise details of texture is seldom discussed. In this paper, an algorithm for incremental reconstruction of the details of periodic textured surface is presented. The concept of polar spectrum is introduced to describe the spatial properties of the surface with respect to the direction of measurement. Based on the relation between spatial frequencies and directions, surface profiles in different directions can be rebuilt from with limited number of scans. Experimental results show the effectiveness of the proposed algorithm.

Generally, object recognition in robotics has used vision, sonar, laser range sensors, etc. In this paper, the authors propose a new sensing technology based on radio frequency identification (RFID) to facilitate the autonomous recognition of objects. This technology uses a novel tag, named the 3-D tag, with which an object can be identified and its orientation together with location can be estimated. This paper presents the method for object recognition by analyzing the characteristics of the 3-D tag, and then validates the 3-D tag through several demonstrations showing its usefulness as an independent sensor for recognizing objects.

In this paper, we investigate comprehensive issues of modularized robot systems and present architecture for effective development of personal robots. The proposed architecture includes the interface and interaction methodology of the hardware modules and the software among the modules. Based on the architecture, we present a fully modularized personal robot dynamically reconfigurable personal robot I. Its hardware modules are easily added to or removed from the original system, and also the distributed software functions of the modules are rearrangeable accordingly. We focus on how to effectively build up the robot, and discuss the dynamically reconfigurable features of it for evaluating the proposed idea and approach.

In this paper, we propose a method of sensing outdoor environments for a walking and climbing robot. The proposed method ensures the realtime perception of the surface geometry by integrating a range and a gyroscope with a novel arrangement of the sensors. In addition, a gait planning algorithm based on the sensing method is presented. The algorithm runs fast since it is simple, and the rich information from the sensing system helps the robot overcome the real environment, even an extremely complex one. The sensing system is implemented in a quadruped walking robot, called MRWALLSPECT IV and its effectiveness is proved experimentally.

In this paper we present an in-pipe robot, called MRINSPECT V (Multifunctional Robotic crawler for In-pipe inSPECTion V), which is under development for the inspection of pipelines with a nominal 8-inch inside diameter. To travel freely in every pipeline element, the robot adopts a differential driving mechanism that we have developed. Furthermore, by introducing clutches in transmitting driving power to the wheels, MRINSPECT V is able to select the suitable driving method according to the shape of the pipeline and save the energy to drive in pipelines. The robot aiming for autonomous navigation is configured with four modules serially connected. Two active driving modules are located in front and rear of the system, respectively. Passive modules are linked between the driving modules. This module-based robot can fit to narrow and winding pipelines by using the novel mechanism such as the specially designed module-joints. In this paper, the critical points in the design and construction of the proposed robot are described with the preliminary results of experiments that yield good mobility and increased efficiency.

In this paper, we introduce a wall climbing robotic system for visual inspection of man-made structures. The adhesion mechanism of our system consists of an impeller and two-layer suction seals which provide sufficient adhesion forces for supporting the robot body on the non-smooth vertical wall and horizontal ceiling by generating pressure difference between the inside of the pressure chamber and the ambient environment. A comprehensive study is performed on the dynamic fluid modeling of the adhesion mechanism and the adhesion force is controlled by adjusting the pressure inside of the chamber. In addition, stable differential-driving locomotion on non-smooth surface are achieved by adapting a suspension mechanism for each wheel. A wall climbing robot, called LARVA, is successfully developed and its effectiveness of locomotion is verified with experiments on non-smooth vertical wall and horizontal ceiling surface.

As a major human sensory function, the implementation of the tactile sensation for the human-machine interface has been one of the core research interests for long time. In this paper, an innovative tactile display device based on the soft actuator technology is presented. Using electroactive polymer for the construction of the tactile display device, it can provide stimulation on the human skin without any additional electromechanical transmission. Softness and flexibility of the device structure, ease of fabrication, possibility for miniaturization, and low cost for mass production are the representative benefits of the presented device. Especially, the device application is open to many different purposes since the flexible structure offers the excellent adaptability to any contour of the human body. To prove its feasibility, a wearable device that can fit to the distal part of the human finger is presented and its performance is evaluated, experimentally.

In this paper, we present a new artificial muscle actuator for the robotic applications, called multi-stacked actuator. This actuator is made from a new material, named synthetic elastomer previously developed by ourselves. The synthetic elastomer displays enhanced performance in terms of electrical as well as mechanical properties, which can be adjusted depending on its applications. The actuator is composed of the synthetic elastomer sheet coated with compliant electrodes on the both sides, connecting disks, spring, and rigid frame. This novel design enables the actuator to generate the large strain as well as the large force. Experimental works are performed to evaluate the actuation performance and the effectiveness of the actuator is validated.

In this paper, a new biomimetic control method for a quadruped walking robot is proposed. The method is derived by the observation of the gravity load receptor and stimulus- reaction mechanism of quadrupeds' locomotion, and the study of the stances on walking and energy efficiency. Though the controller is simple, it provides a useful framework for controlling a quadruped walking robot. In particular, by introducing a new rhythmic pattern generator the heavy computational burden to be paid on solving kinematics is relieved. The effectiveness of the proposed method is validated via a dynamic simulation and experimental works in a quadruped walking robot, called AiDIN(Artiflcial Digitigrade for Natural Environment).

Surface roughness is one of the most intractable physical properties and its sensing heavily depends on the application and the capability of the sensor. In this paper, a pen-type sensor is proposed for sensing surface roughness. The sensor with a rigid contact probe is able to measure 3D contact forces and the dynamic contact responses along the axial direction of the probe, which facilitate the roughness representation using parameters of roughness profile rather than complex, high level interpretation methods. Strain gauges and a force sensor are used for measuring contact forces and a PVDF sensor is used for the dynamic sensing. The sensor is a self-contained one, and it can transmit sensed data via Bluetooth to the host computer. As preliminary tests, experiments are performed on the measurement of the coefficient of friction and the response to dynamic stimuli of different surface patterns.

In this paper a hand-held sensor for surface texture perception is presented. The sensor with a metal contact probe is able to measure the roughness and frictional property of a surface, which are among the most important parameters for contact texture perception. Two strain gauges and a force sensor are employed to measure 3D-contact forces at the tip of the contact probe. The friction coefficient can be calculated by using the normal force and tangential one. A PVDF film is used for the dynamic sensing of contact stress in the axial direction of the contact probe. Measurement results are transmitted to a host computer via Bluetooth wireless communication link for further data processing. Design issues are discussed in details, and the preliminary experimental evaluations are performed.

Tactile sensation is one of the most important sensory functions for human perception of objects. Recently, there have been many technical challenges in the field of tactile sensing as well as tactile display. In this paper, we propose an innovative tactile display device based on soft actuator technology with electroactive polymer (EAP). This device offers advantageous features over existing devices with respect to intrinsic flexibility, softness, ease of fabrication and miniaturization, high power density, and cost effectiveness. In particular, it can be adapted to various geometric configurations because it possesses structural flexibility, so it can be worn on any part of the human body such as finger, palm, and arm etc. It can be extensively applied as a wearable tactile display, a Braille device for the visually disabled, and a human interface in the future. A new design of the flexible actuator is proposed and its basic operational principles are discussed. In addition, a tactile display device with 10times10 actuator array (100 actuator cells) is developed and its effectiveness is confirmed

In this paper, an anthropomorphic robot hand called SKKU Hand II is presented, which has a miniaturized fingertip tactile sensor. The thumb is designed as one part of the palm and provides the mobility of the palm. The fingertip tactile sensor, based on polyvinylidene fluoride (PVDF) and pressure variable resistor ink, is physically flexible enough to be deformed into any three-dimensional geometry. In order to detect incipient slip, a PVDF strip is arranged along the direction normal to the surface of the finger of the robot hand. Also, a thin flexible sensor to sense the static force as well as the contact location is fabricated into an arrayed type using pressure variable resistor ink. The driving circuits for the SKKU Hand II are embedded in the hand, and each driving circuit communicates with others using CAN protocol. In addition, a tactile sensing system is developed with miniaturized electronic hardwares such as charge amplifier, signal processing unit etc., and it is integrated into the robot hand. The SKKU Hand II is manufactured and feasibility of the hand and the fingertip tactile sensor is validated through preliminary experiments

RFID (radio frequency identification) technology has been rapidly and widely applied to various applications. Recently, RFID has been suggested as technology that supports object recognition. This paper introduces the advanced RFID-based recognition. The proposed RFID system not only identifies the existence of the object, but also estimates object's orientation and location. These characteristics considerably reduce the dependence on other sensors which are required for recognizing objects. In this paper, we analyze the characteristics of our system and present a novel tag named a 3D tag. The estimation methods of location and orientation using the system are discussed

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.

One of the traditional problems in the walking and climbing robot moving in the 3D environment is how to negotiate the boundary of two plain surfaces such as corners, which may be convex or concave. In this paper a practical gait planning algorithm in the transition region of the boundary is proposed in terms of a geometrical view. The trajectory of the body is derived from the geometrical analysis of the relationship between the robot and the environment. And the position of each foot is determined by using parameters associated with the hip and the ankle of the robot. In each case of concave or convex boundaries, the trajectory that the robot moves along is determined in advance and the foot positions of the robot associated with the trajectory are computed, accordingly. The usefulness of the proposed method is confirmed through simulations and demonstrations with a walking and climbing robot.

In this paper, a fingertip tactile sensor is presented which can detect contact normal force as well as incipient slip. The sensor, based on polyvinylidene fluoride (PVDF), and pressure variable resistor ink, is physically flexible enough to be deformed into any three-dimensional geometry. In order to detect incipient slip, a PVDF strip is arranged along the direction normal to the surface of the finger of the robot hand. Also, a thin flexible sensor to sense the static force as well as the contact location, is fabricated into an arrayed type using pressure variable resistor ink. In addition, a tactile sensing system is developed with miniaturized electronic hardware such as charge amplifier, signal processing unit etc., and it feasibility is validated experimentally.

Pipelines for the urban gas-supply system require a robot possessing outstanding mobility and advanced control algorithms, since they are configured with various pipeline elements, such as straight pipelines, elbows, and branches. We present a comprehensive work for moving inside underground urban gas pipelines with a miniature differential-drive in-pipe robot, called the Multifunctional Robot for IN-pipe inSPECTion (MRINSPECT) IV. MRINSPECT IV has been developed for the inspection of urban gas pipelines with a nominal 4-in inside diameter. The mechanism for steering with differential-drive wheels, arranged three-dimensionally, allows it to easily adapt to most of the existing configurations of pipelines, as well as providing excellent mobility during navigation. After carrying out analysis for fittings in pipelines, mathematical descriptions of their geometries are presented, which make it possible to estimate the movement patterns of the robot while passing through the fittings. Also, we propose a method of controlling the robot by modulating speeds of driving wheels that is applicable without sophisticated sensory information. To confirm the effectiveness of the proposed method, experiments are performed, and supplementary considerations on the design of the in-pipe robot are discussed.

Architecture and method for accelerating the development of personal robots are presented. It includes the technology such as modularization with its own processing and standardization open to other developers. We mainly focus on the effective ways for integrating the various robotic components and interfacing among them. The architecture is implemented by developing the fully modularized personal robot DRP I (Dynamically Reconfigurable Personal robot). Its hardware component is easily attached to and detached from the whole system but also each software of the components is functionally distributed. As methodology for interfacing and integration of DRP I, we introduce Module-D (Module of DRP I) characterized functionally, VM-D (Virtual Machine of DRP I) and RPL(Robot Programming Languages) for supporting compatibility of each Module-D. As experimental work, the dynamically reconfigurable feature of the robot is introduced.

Tactile sensation is one of the most important sensory functions along with the auditory sensation for the visually impaired because it replaces the visual sensation of the persons with sight. In this paper, we present a tactile display device as a dynamic Braille display that is the unique tool for exchanging information among them. The proposed tactile cell of the Braille display is based on the dielectric elastomer and it has advantageous features over the existing ones with respect to intrinsic softness, ease of fabrication, cost effectiveness and miniaturization. We introduce a new idea for actuation and describe the actuating mechanism of the Braille pin in details capable of realizing the enhanced spatial density of the tactile cells. Finally, results of psychophysical experiments are given and its effectiveness is confirmed.

When a robot navigates in the unstructured environment, it frequently meets various objects capable of being represented as a simple geometrical primitives such as planes, spheres, cylinders, and their combinations. In this paper, we propose a method for the perception of the environment with a low cost two degree-of-freedom IR (infrared) scanner, which can be used for navigation of the quadruped walking robot. Our work is mainly focused on the development of an algorithm for real-time modeling of the environment and the shape reconstruction of the environment. Though the proposed algorithm is very simple, it is useful to determine the geometrical features of the object as well as provide sufficient information for navigation of the robot. Using the proposed method, a method for gait control of the quadruped walking robot can be generated. The validity of the proposed algorithms are demonstrated through experiments using a quadruped walking robot called "MRWALLSPECT III(Multifunctional Robot for WALL inSPECTion version 3)".

When we use a tactile sensor, sensing mechanism and restoration of texture from electric sensing signals are important issues. The objectives of this research are to design a new texture sensing system and to develop a new signal processing algorithm which can restore various texture. The new texture sensing system is designed to get texture with high resolution and wide velocity range, which uses a PVDF sensor and has fixing components for several types of objects in precise condition. Next, a new signal processing algorithm is developed to restore texture. In the previous researches, forward model is needed and then it is inverted by using some regularized inversion formula in frequency domain, where there exist problems such as amplification of noise due to ill-posedness, modeling uncertainty due to orientation and position of PVDF films and silicon rubber, and difficulty to add nonlinear terms into model in frequency domain. While, in this paper, we model directly the relation containing transient-state from measured signals to texture by using model structure of multi-input multi-output nonlinear autoregressive moving average and a time domain least squares estimation. The direct modeling can be done by the use of F/T sensor which is not used in the previous researches. Finally the several texture is experimentally reconstructed from sensing signals using the developed signal processing algorithm.

In this paper we present a packaged actuator to be applied for micro- and macro- robotic applications. The actuator is based on polymer dielectrics, and intrinsically has muscle-like characteristics capable of performing motions such as forward/backward/controllable compliance. The actuator is featured in several aspects such as simplicity and lightness in weight, cost-effectiveness, multiple DOF-actuation, and digital interface. In this paper, its basic concepts are briefly introduced and the issues about design, fabrication and applications are discussed.

This paper describes an integrated approach for the design of a quadruped robot, called "MRWALLSPECT III (multifunctional robot for wall inspection version 3)", which walks in planes as well as climb walls with suction pads. Since the robot is expected to be able to move from wall to wall to plane including negotiating convex or concave corners, a comprehensive study is needed to develop the robot by performing intuitive and geometrical analysis, critical aspects of design such as joint ranges, design of ankles, and location of actuators are discussed. Environmental geometries are classified into several groups, and criteria for design are proposed for each case. The proposed criteria are applied to the actual design of MRWALLSPECT III designed to carry an ultrasonic NDT tool for inspection of the large surface of industrial utilities. By implementing the proposed idea on the robot its effectiveness is experimentally confirmed.

In this paper a new soft actuator based on dielectric elastomer is proposed. The actuator, called an antagonistically-driven linear actuator (ANTLA), has the muscle-like characteristics capable of performing the motions such as forward/backward/controllable compliance. Due to its simplicity of configuration and ease of fabrication, it has the advantage to be scale-independently implemented in meso- or micro-scale robotic applications. Its basic concepts are introduced and a quasi-static analysis is performed with experimental verifications.

In this paper a new soft actuator based on dielectric elastomer is proposed. The actuator, called an antagonistically-driven linear actuator (ANTLA), has the muscle-like characteristics capable of performing the motions such as forward/backward/controllable compliance. In this paper, its dynamic analysis is performed with experimental verifications, and applications for robotic actuating devices are introduced.

In the previous reports (2001), we presented a miniature inpipe robot called MRINSPECT (Multifunctional Robotic crawler for INpipe inSPECTion) IV which has been developed for the inspection of urban gas pipelines with a nominal 4-inch inside diameter. Its steering capability with three-dimensional differentially driven method provides the outstanding mobility for navigation and the new mechanism for steering can easily adjust itself to most of pipelines or fitting, in which other former inpipe robots can hardly travel as ever. In this paper, we present the strategy and the critical points established on using the speed modulation for the navigation in elbows and branches. The analysis for the navigation inside fittings and curved pipelines is given in detail and it is addressed how to compute the speeds of the independent wheels for the differential drive in elbows and branches.

In this paper a microrobot, mimicking annelid animals like the earthworm, is presented. The robot is composed of several ring-like segments. Each segment is able to generate three degree-of-freedom motions such as pan/tilt/up-down respectively, and it is actuated by three soft actuators located equidistantly along the circumferential direction. The soft actuator, called antagonistically-driven linear actuator (ANTLA), is based on polymer dielectrics and has muscle-like characteristics capable of performing motions such as forward/backward/controllable compliance. In this paper, the basic concept of the actuator is briefly reviewed and the robot, including the ring-like segment, is explained in detail with demonstrations.

As changing the eating habit to low fiber and high fat diet, the pathology in the colon is growing up annually. Colonoscopy is an important medical procedure for the diagnosis of various diseases like cancer in the colon and rectum. But it requires much time for doctors to acquire a dexterous skill to perform the operation of colonoscope and the procedure is painful and long to the patient in many cases. Therefore, some studies on the development of autonomous and more convenient colonoscope are carried out. In this paper, we propose a smart colonoscope system that has the locomotive function, active camera system, and human-friendly user interface besides the basic functions of the conventional colonoscope system. Doctors will be able to concentrate on the diagnosis itself with this system. The dexterity required to doctors and the pains imposed to patients will also be reduced with this system. The concept and each component of the smart colonoscope system are described in this paper. We carried out in-vitro test to evaluate its validity.

We introduce the robots called MRINSPECT (multifunctional robotic crawler for inpipe inspection) III and IV which are under development for the inspection of urban gas pipelines. The proposed robots can freely move along the basic configuration of pipelines, such as horizontal or vertical pipelines. Moreover, it can travel along reducers, elbows, and steer in the branches by using steering mechanisms. Especially, their three dimensional steering capability provides outstanding mobility in navigation that is a prerequisite characteristic in urban gas pipelines. Their critical points in the design and construction are introduced with preliminary results of experiments.

If we install an electrode such as conductive grease or carbon powder in both sides of an electrostrictive polymer film, then it becomes a parallel-plate capacitor using electrostrictive polymer as dielectric. When the voltage is applied to electrodes, charges are piled up on the electrodes. Then, there is an attractive force between charges in the anode and cathode. This force acts as pressure in the direction of thickness, so electrostrictive polymer expands in the direction of area by its incompressible characteristic. When the voltage is off, electrostrictive polymer returns to its original shape. In this paper, we realize an electrostrictive polymer actuator using the deformation of electrostrictive polymer, and design and implement the control system of this actuator. Using this control system, we analyzed its actuation and motion control. In order to do that, we analyzed the relations between voltage and displacement. Also, the characteristics of this actuator were measured under some control techniques.

A self-contained wall-climbing robot called MRWALLSPECT-II, is presented. The robot has characteristic features in the kinematic design of the leg with closed link mechanism. It reduces the number of actuators compared to the previous ones and makes it possible to have high force-to-weight ratio. Those are enabled by adopting a simple and robust gait pattern mimicking a living creature. Also, as the robot is designed to be a self-contained one, it includes all the components such as air compressors, vacuum generators, an embedded controller, batteries, a CCD camera, sensors, motors and electronics in itself without any tether cable. Its communication with the operating site in the ground is conducted through wireless LAN. In the paper, its principles of design and configuration of the robot are introduced.

We present a robotic joint mechanism that makes it possible to mimic the human-like motions. The proposed robotic joint, called the double active universal joint (DAUJ), generates a two-degree of freedom motion suppressing rolling by the coupled motions of two independent motors. The mechanism design and kinematics are mentioned. Two application examples are outlined: an anthropomorphic finger and an in-pipe inspection robot. The results of basic experiments are reported to confirm the effectiveness of the proposed mechanism. Also, we briefly introduce the advantage that the compliance of the proposed mechanism can be easily controlled by modulating the engagement period of the magnetic clutch.

We present a new 2-DOF anthropomorphic joint mechanism that makes it possible to mimic the human-like motion completely. The proposed joint, called double active universal joint (DAUJ), generates the 2-DOF motion free of rolling by the coupled motions of two independent motor-clutch pairs. Also, it has the advantage that the compliance of the mechanism can be easily controlled by modulating the engagement period of the magnetic clutch. The mechanism design and kinematics are described and two application examples, an in-pipe inspection robot and an anthropomorphic finger, are outlined. In addition, basic experiments are performed to confirm the effectiveness of the proposed mechanism.

We present an exoskeletal haptic device called SKK Hand Master. The device is semi-directly driven by linkages with ultrasonic motors, which has characteristic features close to cybernetic actuators. In the control of the device, we propose a method of measuring the joint positions and joint torques of the finger and a control method called PWM/PS is presented to overcome the intrinsic disadvantages of ultrasonic motors such as hysteresis. Construction of the device is addressed and several results of experiments for performance evaluation are included.

A compact and robust wall climbing robot, called MRWALLSPECT, has been developed. The robot is designed for scanning external surfaces of gas or oil tanks and inspecting defects with nondestructive testing tools during navigation. It accomplishes fundamental three-degree-of-freedom locomotion such as translation and rotation over the wall with a novel closed link mechanism that we have originally devised. Its design and implementation issues are discussed and the results of tests are addressed.

We present a robot system for in-pipe inspection of underground urban gas pipelines. The robot is configured as an articulated structure like a snake with a tether cable. Two active driving vehicles are located in front and rear of the system, and passive modules such as a control module are chained between the active vehicles. The proposed robot has outstanding mobility offered by a new steering mechanism, called double active universal joint, which makes it possible to cope with complicated configurations of underground pipelines. Characteristic features of the system are described and the construction of the system is briefly outlined.

In this paper we propose a method of determining the local curvature of a three dimensional convex object using the force and torque information obtained from the active touch of a robot finger. A technique for estimating two dimensional curvature of a convex object are introduced and the way of computing the three dimensional curvature from the two dimensional curvature is presented. Also, we develop an experimental system consisting of a finger and verify the effectiveness of the proposed method experimentally.

In this paper, two points are addressed as for the stiffness control of redundant manipulators. The first is, through the joint stiffness analysis, a generalized stiffness model between the joint and taskspace stiffness. Differing from the previous stiffness model, this model shows the existence of the additional stiffness concerning the configuration change and force. The second is the joint stiffness control scheme of redundant manipulators based on the developed model, called orthogonal stiffness decomposition control. The effectiveness of the proposed model and control method is verified through simulations and experiments.>

The stiffness of a grasp is analyzed on the basis of the generalized virtual stiffness (GVS) model. Considering that the normal and lateral stiffness of the finger usually are not decoupled due to kinematics and mechanical design, GVS is formulated as coupled virtual springs. The authors relate GVS to the effective fingertip stiffness including the additional stiffness at the joint space. Based on the grasp stiffness formulation, simulations were carried out, focusing on the grasp stability.