This paper proposes a detection method of tongue motions based on EMG signal around a frontal neck, which is used to control a support device for quadriplegic patient. This method extracts some features of EMG signal that is measured by multiple array electrodes attached on a skin surface of a frontal neck. A Support Vector Machine (SVM) in the method classifies the signal into six kinds of the tongue motion, since the SVM is a potent pattern recognition algorithm in weakly nonlinear system. We investigate the performance of the detection algorithm through the experiments and then confirmed that accuracy of all motions' detection is more than 92%.

View full abstract

A life support system using robotic physical agents for partial disabled people has been addressed. Concept and design of a newly developed end-effector, which assist user' s daily operations of home appliances such as sanitary ware, health care equipment and so on, is proposed. The device can control the distributed appliances in user's room environment by connecting its end-effector to the corresponding attachment on appliance. Experimental results of a prototype device called "mGEAR" show the it's motion characteristics as well as the effect of connecting tolerances on the power transfer performance.

View full abstract

In this paper, a new kind of omnidirectional wheelchair typed robot is developed. The robot not only can accomplish the walking support or walking rehabilitation as an aged person or a disabled person is walking, but also can realize power assistance for a caregiver when he/she is pushing the robot to move. The basic structure of the robot is described and the principle of omnidirectional movement of the robot is presented. Further an admittance based human-machine interaction controller is introduced for power assistance. Moreover, an approach of the power assistance on a slope with speed compensation is proposed, and the experimental verification the availability of the approach.

View full abstract

A quantitative and effective evaluation index of a human lower limb movement is wanted in clinical gait analysis. In our labolatory, we have developed "Leg motion measurement system" to create effective evaluation index which can be applied for gait analysis in the future. In this paper, we will discuss the possibility of the system based on the gait measurement experiment for elderly people.

View full abstract

The purpose of this study was to examine effect of muscle spindle function in lower-leg muscles during walking on stiffness change surface. The subject were 10 healthy young adult males. We measured usual and high speed walking on even and stiffness change surface, and compared healthy state and reduced muscle spindle function state. This study adopted applying iced water over lower-leg muscles as a method of reducing the muscle spindle function. Stiffness change surface was made of sponge and acrylic plate. In high speed walking on stiffness change surface, step width standard deviation increase significantly. Additionally, in reduced muscle spindle function state, velocity increase after sponge and adjustment of step length retard significantly. Increasing step width standard deviation suggest unsteady gait. Therefore the muscle spindle function is important to walk on stiffness change surface. Increasing velocity after sponge and retarding adjustment of step length suggest that muscle spindle function is important to walk on other uneven surface.

View full abstract

This paper proposes a measuring device that uses carrier phase positioning GPS and an accelerometer for pitch and stride measurement of sprinters. In this system, synchronization between GPS data and step timing is used to measure pitch and stride. In this paper, improvement of the measurement system, and the method for detecting step timing by measuring the acceleration of the lumbar is discussed. Results of sprinters pitch and stride measurement by using improved measurement system are presented.

View full abstract

In this paper, we investigate the relationship between motion of the human upper limb and weight sensation during weight-lifting experiments in real environment. The weight-lifting are completed under the conditions of different lifting height and arm restraint. The subjects evaluate the lifted weight by the method of magnitude estimation. Results of psychophysical magnitude function and psychometric function are computed. Slope of psychometric function and modality characteristic exponent were analyzed for the experiment conditions. The results show that force sensation is easy to be perceived in the experiment of long distance lifting. The relationship between motion of the human upper limb and weight cognition is carefully discussed.

View full abstract

This paper describes an unconstrained gait measurement method by using a mobile robot as one of a service for perceiving human's health. Human's gait is measured based on feet recognition by the mobile robot equipped with the Kinect sensor. The mobile robot detects ankles and instep using the Kinect sensor. Furthermore, the mobile robot computes swinging time on gained coordinate of ankles and instep of images with running parallel to a target person. Experimental results show a usefulness of proposed method by comparison of estimated value with an actual measured value.

View full abstract

Recently, urban development planning has been built based on Barrier-Free Transportation law in Japan. Most of buildings have been designed according to this law, and the designs of house furnishings have been enhanced accordingly. By the way, no numerical criteria that reduces the physical loads of pedestrian has been set yet. Then, this study aims to propose a numerical criterion that is focused on pedestrians' senses in gait motion and aides to design the pedestrian space that reduces the physical load of pedestrian. To consider the pedestrian's feelings in gait motion, this study has focused on the mechanism of ankle's joint and surface electromyography of lower limbs. We analyze these information statically and investigate the trends due to the kinds of properties of pavements.

View full abstract

The passive dynamic control (PDC) is a new control method based on the inherently safe design, and it realizes a high-safety control by using passive element mainly. The PDC divides the control process into some steps, confirms the safety in each step, and permits the execution. The braking device is indispensable to prevent execution being output until safety is confirmed. In this note, the PDC is applied to the angle control of the inverted pendulum. By taking necessary energy to move the pendulum from translational vibration, the continuous positioning control and follow-up control are realized by using the brake operation.

View full abstract

To achieve high backdrivability in transmission, it is an effective approach to decouple the dynamics of actuators. Electro-Hydrostatic Actuators (EHA) which is modeled as a decoupled dynamics by damping element can achieve high backdrivability. However, accurate modeling of energy loss and damping in hydraulic transmission is difficult, which requires controllers with robustness to modeling error. In this paper, we derive a model of a manipulator actuated by EHA and propose a passivity-based controller for the EHA driven manipulators. The proposed controller consists of PD control and gravity compensation based on link joint angle and velocity feedback. The whole dynamics is composed of two passive subsystems, link and pump dynamics, and asymptotic stability is given. The efficacy of the proposed controller was evaluated by experiment.

View full abstract

Joints of humanoid robots must be backdrivable in order to make them able to withstand collision and impact. The objective of this research is to propose new composition and design of lower limb of humanoid robot with electro-hydrostatic actuator (EHA), a class of backdrivable actuator. We introduce a joint that is composed of bi-articular EHA and mono-articular EHA. Bi-articular EHA has a single pump and two hydraulic motors which are connected to the pump in parallel, while mono-articular has one for each. This paper explains composition and design concept of the EHA joint. Overview and detailed design of the joint are also presented. the design specification of each EHA on the joints was determined by the joint output of human body.

View full abstract

Recently, robotics has been applied to not only industrial areas but also cooperative works with humans. For example, life support robots and entertainment robots are developed. The purpose of this research is the development of a safety robot in cooperative works with humans by using an Extremely Lightweight Soft Actuator. The Extremely Lightweight Soft Actuator using pleated plastic films is driven by pneumatic pressure. The design method and the application to the soft actuator are novel approaches. We will describe the design method of the Extremely Lightweight Soft Actuator in this paper.

View full abstract

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a flow (ECF flow) by applying high DC voltage between electrodes inserted in the fluid. It is known that a strong ECF flow is generated under non-uniform electric field. This study introduces the ECF flow to develop a turbine motor. The turbine motor mainly consists of an ECF flow generators, a turbine rotor and a flow path. ECF flows inside the turbine motor and makes the turbine rotor rotate. First, we characterized the ECF flow generator and the turbine rotor. Next, we developed the turbine motor using ECF. Finally, we evaluated no-load rotational velocity, output torque, output power and output power density of the turbine motor. The experimental results confirm the motor developed has a higher performance than the previous ECF motors.

View full abstract

We developed servo valve which realize a small flow rate by making the diameter of spool small, and the low leakage by long overlap and divided sleeve. Moreover, the performance of the servo valve was evaluated. In addition, we introduce the performance.

View full abstract

We focuses on the trajectory of eyes and hands of the student movement for the engineering experiments, we propose an assessment method of the engineering experiments skill. Then, we constructs a simple skill assessment system using the infrared equipments and microcomputers. This system detects the movement of eyes and hands by infrared LED and an infrared sensor, and records the trajectory data in tablet PC via microcomputer. The skill assessment score obtain by using these data. We verified the validity of assessment method, and the simple skill assessment system by experiments.

View full abstract

Brain Machine Interface (BMI) is a system that assumes user's intention by analyzing user's brain activities and control devices with the assumed intention. It is considered as one of prospective tools to enhance paralyzed patients' quality of life. In our group, we especially focus on ECoG (electro-corti-gram)-BMI, which requires surgery to place electrodes on the cortex. We try to implant all the devices within the patient's head and abdomen and to transmit the data and power wirelessly. Our device consists of 5 parts: (1) High-density multi-electrodes with a 3D shaped sheet fitting to the individual brain surface to effectively record the ECoG signals; (2) A small circuit board with two integrated circuit chips functioning 128 [ch] analogue amplifiers and A/D converters for ECoG signals; (3) A wireless data communication & control device with the PC installing its dedicated software. At the present stage, the Bluetooth chips are temporally applied; (4) A non-contact power supply transmitting electrical power minimum 4[W] to the device 10-40[mm] away. We developed those devices, integrated them, and, investigated the performance.

View full abstract

This paper proposes a novel technique to visualize upper and lower-limb human motion by means of surface electromyography, and measuring kinematics of human motion. The developed wearable light-emitting sensor suit indicates lower-limb muscle activity on the surface of the body in real time, by displaying the shape of the innervated muscle on the position of targeted muscle. We investigated the possible applications of the sensor suit in the fields of rehabilitation, and indicate the method of future rehabilitation.

View full abstract

Surface electromyography (SEMG) has been used to detect the muscular activity in the field of biomechanics. By the way, the effects of muscular fatigue on SEMG have been studied and some frequency analysis methods such as first Fourier transform (FFT) and continuous wavelet transform (CWT) found the quantitative and qualitative alternation appear on the time-series of SMEG. However, it is difficult to estimate muscular fatigue quantitatively from SEMG analysis yet. Then, this study focuses on the pattern entropy method that compresses time-series signal with focusing on the instability, and attempts to apply this method to SEMG in order to quantitatively estimate the effect of muscular fatigue onto time-series signal of SEMG. The possibilities of the pattern entropy method to evaluate muscular fatigue from SEMG are discussed with comparing to the time-series data of power spectrum coefficient and frequency coefficient of the resut of gabor's CWT.

View full abstract

Our previous work has demonstrated that rubber hand illusion (RHI) can be elicited under active self-touch, in which participants can stimulate both their own hand and a rubber hand by using a master-slave system. This paper, in particular, discusses force feedback effect on the RHI under such unique condition. In our RHI paradigm, the participants give haptic stimulations such as tapping and stroking their hand and the fake hand. In this condition, if the tapping force on the fake hand and the contact force on the real hand have large difference, the participants might have strange feeling and would not experience the RHI; we assume that the force feedback plays an important role to determine our body ownership. Then, this paper examines how the force feedback affects the RHI under the active self-touch by changing the magnitude of force rendering on the master device.

View full abstract

The actuator which could achieve reduction of its weight and decrease in consumption of the energy simultaneously by engineering reconstruction of the muscle contraction process was discussed in this study. It can be used as structural materials. The mechanism simulated the signal transduction process inside neuron cells was also proposed here. The prototypes for both of them were designed and made, and then the results of operation tests were shown.

View full abstract

This paper proposes a new soft actuator which imitates the structure of muscles of the octopus arm. The octopus can perform various operations such as passing through narrow gaps or grasping with its arms while adapting to the shape of the object. The octopus performs such operations due to its peculiar muscular structure, named muscular hydrostat which does not change its volume during muscle contractions. In this paper the biomimetic actuator, composed of a shape-memory alloy and urethane gel, aiming to search and rescue at disaster sites is discussed. The shape-memory alloy is used for generating force of contraction, and urethane gel is for maintaining its volume during contractions. Finally, the methods with which the actuator achieves various movement like bending, contraction, elongation, and twisting are showed.

View full abstract

In recent years, soft actuators having flexible movement attract attentions. There are some soft actuators such as McKibben actuator, shape-memory-alloy actuaor (SMA), functional fluid actuators, etc. But almost all of them are expansion and contraction type of actuators, so their application field is limited. If rotary type of soft actuator is realized, they will be easily applied to traditional robots, and also to soft robots. In this research, for the purpose of realizng a soft actuator which can output rotary motion, we developed an electrostatic motor made from flexible polyester films with electro conductive polymer electrodes fabricated by line patterning method.

View full abstract

Recently, human and robots have started to work together in the field of medical treatment and welfare. In such an environment, it is required that robots operate in a safe manner that avoids collision or inadvertent contact with human colleagues. This study desrcibes the development of a manipulator with the opposed placement type electro-rheological (ER) clutches contributing a collision force reduction. The main feature of developed manipulator is the structure that sandwiches the link between two ER clutches and equips the link with a pneumatic cushion. Thus, the input shaft of each clutch is rotated in the opposite direction via a bevel gear, a spur gear, and a motor. As a result of reversing the link by switching the clutch, the manipulator can high-speed reverse. As well, position control, reverse motion control and collision experiments were performed regarding the developed manipulator.

View full abstract

A pump capable of transporting high-viscosity fluids and solid-liquid mixtures is required in various industrial settings. Turbine-type pumps, piston-type pumps and squeeze-type pumps are often used to transport high-viscosity fluids and solid-liquid mixture. However, these types of pumps have disadvantages. Hence, an innovative transport system is desired. In this paper, we focus on bowel peristalsis as a model for a mechanism that can transport fluids, such as sludge with little water. We developed a peristaltic pump based on the bowel mechanism by using an artificial rubber muscle, and confirmed its capabilities. In addition, we develop new tube to achieve a perfect close of the tube, and confirm the basic characteristics of the new tube. Finally, we measure the suction pressure and flow rate and confirm the perfect close of the tube.

View full abstract

ER (electro-rheological) gel is one of functional materials, which adhesive force increases when an electric field is impressed. In this study, an ER gel is equipped for the human body directly to realize effective rehabilitation or force display. The property of ER gel is applied to a brake element. However, ER gel is used at a curved form, when it is set up on the human body. The force property of ER gels on the curved surface is not known well. Therefore, we develop an experimental device for pre-study on force display, and measure the adhesive force using the device.

View full abstract

This paper deals with the method for improving the performance of motion capture. There are many types of motion capture. In this study, the authors use ordinary USB cameras. Though USB camera is convenient and low cost, their performance is not very high considering to employ for motion captures. Then, the authors propose a new method to improve the performance USB camera based motion capture. In their method, multiple USB cameras sequentially take images to equivalently enhance time resolution. They tested basic validity by a preliminary experiment.

View full abstract

In this study, we investigated human locomotion by dynamics simulation analysis. We extracted major mode of human locomotion using Singular Value Decomposition (SVD) method from motion capture data. And we investigated feature of major mode by dynamics simulation of reconstructed major modes of locomotion. As a result, dynamic locomotion by the major modes.

View full abstract

In this paper, in order to extract the evaluation index of dexterity of hand, we propose a method for measuring the movement of the hand. As the measurement method, we propose a color glove. Color glove method is to convert the tiny image of the hand image was taken with the camera. And to estimate the pose by comparing the tiny image and the image pattern in the database. Color glove method, occlusion occurs. Occlusion is that part of the hand might be hidden in the camera's blind spot. Order to solve the occlusion, we propose a method to avoid occlusion using multiple cameras.

View full abstract

The chest compression is one of the most important actions for Cardio Pulmonary Resuscitation (CPR). Because many people will be survived by the CPR in the early-stage of cardio-respiratory arrest, it is expected the chest compression become widely known through training. The chest compression is accompanied with an internal force and it is difficult for trainees to understand the required force only from the demonstrations. In this paper, we develop an enhanced motion that enables the trainees to yield the required force for the chest compression. The skilled motion is captured and modeled by an autonomous control system containing the information of human motion. Based on the decomposition of the controller, Pseudo-reference is designed. Through the training with/without Pseudo-reference, the effectiveness of the enhanced motion is evaluated.

View full abstract

To evaluate KEIROKA technology by the brain activity, investigation of cerebral blood flow due to brain activity is conducted by using functional near-infrared spectroscopy (fNIRS). However, it is difficult to measure the brain activity using fNIRS during exercise because cerebral blood flow changes due to head motion not to neural activity. The head motion component is an obstacle to measure the brain activity. This research tried to estimate the head motion component by using 3D Motion Capture. And the head motion component was estimated by the pitch angle. The author also tried to subtract the head motion component from fNIRS data during exercise. The way to remove will be shown.

View full abstract

Recently stimuli-responsive polymer gels have been applied to soft actuators. Especially, electroactive polymers are said to be promising material. Its mechanical motion is controlled by the external stimuli such as a change in solvent composition, pH, temperature and electric field etc. On the other hand, living organisms exhibit an autonomous motion driven by the chemical energy. The gel actuator converts the chemical energy of the oscillatory reaction into the mechanical energy inside the gel. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it is alive.

View full abstract

Evaluation of operating characteristics by the structure and curvature change of FFP-actuator. First, we attached SMA to the thin plate like a bow. SMA was then changed into 65 mm from 40 mm. Next, this FFP actuator was applied to the flexible robot. As a result, one 8 times the movement speed of this improved rather than the conventional robot. We showed that it was related to the amount of displacement (curvature) and movement speed of a FFP actuator by experiment.

View full abstract

We proposed a novel plasticized PVC gel actuator using fringe electrostatic field. Both ends of gel beam were supported on two grounded electrode. A bottom electrode applied voltage was formed under the gel. A gap between the bottom electrode and gel was 500 μm. When the voltage was applied, the gel was attracted the bottom electrode by electrostatic force. The gel actuation was simulated by finite element method (FEM), which the amplitude of displacement was 10 μm at 500 V amplitude of voltage. The fabricated gel actuator was resonated at 150 Hz/500 V amplitude of voltage, in which the amplitude of displacement was 120 μm.

View full abstract

Highly rigid actuators such as a geared motor or hydraulic actuator are widely used in industrial robots. To obtain high-speed motion, it is necessary to increase the actuator output as the robot weight increases. In contrast, humans perform motions with instantaneous force-as in a jump or throw-via variable viscoelastic characteristics. Therefore, we developed a 1-DOF manipulator with variable viscoelastic joint using a artificial muscle and a magnetorheological (MR) brake. In this paper, we proposed the method of generating instantaneous force for this manipulator. Further, the experiment of the proposed method was also conducted. As a resutl, we realized generating instantaneous force by proposed method.

View full abstract

This paper focuses on multiple unit control method to get fast response of SMA using resistance as feedback. Due to the existence of hysteresis effect, it is difficult to eliminate the latency time in order to get fast speed. Instead of controlling a single SMA wire, it is a useful method to acieve this aim by combining several units together named as multiple unit control method. The equations of the resistance, displacement and force have been developed because of the approximately linear relationship. The simulation results demonstrate that the proposed method shortens the cycle time of SMA actuator, especially for thick SMA.

View full abstract

The compliance device developed by the author can adjust the mechanical characteristics, and control force/velocity/position of operation between a robot and a targeted workpiece without using a force sensor. In this paper, estimation method of bad fit in assembly task using the compliance device is reported.

View full abstract

In this paper we develop an estimation model of foot-ankle muscular activity for designing an ankle-foot orthosis. We used Baysian network for building the model and evaluate the model. Especially we talk about conformity with actual muscle activity. Our model has three advantages. First, it can express the influences, which change throughout the gait, because we use 10% level nodes of each factor. Second, it can express the influences of factors, which are different for low and high muscular activity legels. Last, the model can compensate the missed estimations by estimating every 10% level muscle activity. In an evaluation of this model, we confirmed that this model can estimate all muscular activity level with an accuracy rate greater than 90%.

View full abstract

In this paper, motion efficiency in arm reaching movements is evaluated by a musculoskeletal model of a human arm. The arm model is composed of two links with six muscles. The motion efficiency is evaluated based on the muscle activity during the motion estimated by an optimization calculation. The stimation results show that the proposed method can suggest suitable layout for individuals.

View full abstract

Humans control the stiffness of joints depending on type of the target task. This implies that profiles of the stiffness includes fruitful information about skillfulness of the human performing. The purpose of this research is to analyze motions by estimating the stiffness and equilibrium points of joints based on sEMG measurements and musculoskeletal model. In this paper, the proficiency evaluation method is proposed based on the calculation of the stiffness ellipse and the trajectory of the equilibrium points of joints.

View full abstract

We present a new apparatus, excursion controller, to measure and analyze musculoskeletal motion of cadaveric fingers. The result of the preliminary experiment clearly shows that the range of excursion of the interosseous for abduction-adduction and that of the extensors for hyperextension were estimated to be 5 to 8mm, while that of the flexors for full-flexion were estimated to be 35mm from the reference posture.

View full abstract

The contribution of lumbrical muscles for the articulated finger motion is yet to be clarified. In this paper we analyze the role of the lumbrical muscle by using excursion controller and cadaver specimens. The result of the experiment clearly shows that the activation of the lumbrical muscle enlarges the arc of the fingertip trajectory except in the hyper extended and fully flexed postures in which taut collateral ligaments constrain the free articulated motion.

View full abstract

Bricolage, which French anthropologist Levi-Strauss firstly raised as a primitive style of creative thinking, means making do with limited and available materials and tools at hand to create new things or to solve problems. It is shown that various forms of bricolage can be widely observed in the field of robotics, based on the author's own experience and several examples, i.e., humanoids using servos for radio control models, robots used in Fukushima nuclear disaster, and constructionism theory in robot education. It is emphasized that bricolage plays a key role at practical scenes of creative activities in robotics.

View full abstract

We introduce a mechatronics education program using an autonomous contrl robot. This program is performed to the fourth grader of a technical college. This time, engineers of an enterprise were invited as an adviser and cooperated this program. In this paper, we introduce the result of the mechatronics education program.

View full abstract

Artec products are used in kindergartens, elementary schools, junior high schools, and high schools all across Japan. The new course on the measurement and control by program is fully implemented in 2012. So, new education tools are required. Artec developed Program Control Tracer and Easy Programmable Robot. We describe the approach to educational robots and development of new education tool.

View full abstract

The small-sized humanoid robots are sold from some companies. Because the most of the robot are for hobbies, they are unsuitable for education use. Then we develop a simulator as teaching materials system and get ZMP and data of the joint torque by simulation. In addition, the making of motion data with simulation is enabled, too, and even few robots can perform education. The student may get deep consideration by comparing the operation of the robot actual machine with data provided from a simulator. We were able to make a motion with the simulator which we developed. And we confirmed that the simulator did a playback of motion data. We acquire various data by a simulator and can save it.

View full abstract

We developed the educational materials that enabled to design a control circuit incorporating a microcomputer. Though the specification of microcomputers differ depending on their kind, there are many similarities in their learning procedure. The learning procedure to develop an electrical circuit using a microcomputer was proposed to order to understand the learning flow. In addition, learners were able to confirm the degree of understanding on their own, by developing a robot to play music, named "barcode player". The questionnaire's result provided us the effectiveness of the educational materials.

View full abstract

We have developed a learning environment for embedded system design. The learning environment consists of a multi purpose controller and Terminal Devices. The controller consists of main processor (arm) and a multi core microprocessor (Propeller). The main processor provides software development environment. The Propeller chip has eight 32-bit processors and can perform simultaneous tasks for multi users. In addition, the Propeller chip realize reconfigurable peripheral module. This feature is very useful for the development of educational materials. Teachers can develop various educational materials with this control module.

View full abstract

It is important to understand the control system of human movement when we develop robot manipulators or prosthesis devices. As muscle models, Hill type models have been used by many researchers. However, there are some limitations in the model when we calculate nonlinear behavior such as shortening-induced force depression. We have proposed a systematic motor model that has a controller based on chemical scheme of myosin cross-bridges. The systematic motor model consists of a converter, a controller and a muscle model. The muscle model has two parallel Maxwell elements and a force generator. It is designed that the systematic motor model is driven by artifical action potential (AAP) to generate force. Then, the AAP is calculated from surface electromyography (SEMG) which is detected at the belly of biceps. We compared simulation results with force obtained experimentally.

View full abstract

The paper describes development of a shoulder joint teaching equipment for the athlete to learn proper movement of his shoulder in such sports and games as baseball and tennis. A simple 4DoF model of the scapula, which can change position relative to the human body, is proposed. The scapula is attached to the human body via four or more muscles. The proposed model has links between the scapula and the human body, and four sliding actuators. The motion of the scapula is analyzed, the position and posture of the scapula are obtained, and actuators' output force is analyzed. In order to examine the validity of the analysis, the result is compared with the past studies.

View full abstract