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In this paper we introduce an adaptive control scheme for robots with elastic joints (in particular for the DLR medical robot) in order to increase the positioning accuracy and the performance of control with respect to uncertainties of the parameters of the robot dynamics. In order to design control and analyze system stability a static friction model is applied which describes Coulomb, viscose and...
We propose a novel method for movement assistance that is based on adaptive oscillators, i.e., mathematical tools that are capable of extracting the high-level features (amplitude, frequency, and offset) of a periodic signal. Such an oscillator acts like a filter on these features, but keeps its output in phase with respect to the input signal. Using a simple inverse model, we predicted the torque...
Passive and active movement therapies are essential in the rehabilitation process post stroke and other neurological disorders. Considering the shortage of therapists and limited insurance coverage, qualified healthcare services are not always available to patients. There is also a lack of compact rehabilitation robots powerful enough to perform forceful stretching of spastic joint and yet flexible...
We proposed a framework of using neural oscillators to control a robotic suit which learns to synchronize with the human user's motion. The robotic suit is a lower limb exoskeleton consisting of four actuators which are fixed to the places where the human hip joints and knee joints are. Each actuator has a built-in harmonic drive gear which is equipped with a torque sensor fixed on the flex-spline...
This paper investigates the control algorithm of an exoskeleton for hand rehabilitation, which accomplishes both active and passive rehabilitation training. In the passive mode control the PID control algorithm is executed in the velocity mode of the driver. In the active mode control, control architecture is proposed to deal with in both free space and constraint space. A resistance compensation...
We have proposed a leg-shaped haptic simulator (Leg-Robot) that provides an environment for young physical therapist to learn rehabilitation techniques or diagnosis techniques with haptic information which mimics a real patient with abnormal motor function, for example, stroke or spinal cord injury. In previous studies, we also proposed a control method to develop a clonus-like movement for the Leg-Robot...
Safety issue has become the primary concern in wheelchair mounted robotic arm applications. We introduced mechanical gravity canceller in the design to realize a light weight manipulator, which also yield the greatly simplify of manipulator dynamics. Based on the simplified dynamics, sensor based contact detection can be easily implemented to enable safety. Contact reaction schemes are also applied...
This paper reports support effects of an exoskeleton system for activities of a hand and an upper limb of a healthy person. The support system augments human forces of a hand, a wrist joint and an elbow joint based on bioelectric potential of each muscle so that the upper limb could be assisted by the exoskeleton with a certain rate of wearer's force. Actuators in the assistive system are replaced...
In this study, an energy-efficient gait pattern and swing trajectory of the powered robotic exoskeleton was proposed through function distribution analysis and the dynamic-manipulability ellipsoid (DME). The exoskeleton has 3 DOF at each side, and it is possible to determine the minimum energy consumption of the joint torques under level-ground walking and stair ambulation conditions. To verify its...
Backdrivability is a keyword with rising importance, not only in humanoid robots, but also to wearable robots. Power assist robots, namely exoskeletons are expected to provide mobility and independence to elderly and people with disability. In such robots, without backdrivability, error between human and robot motion can be painful; sometimes dangerous. In this research, we apply a type of hydraulic...
We aim at experimental verification of the efficiency of natural-motion path tracking (i.e. tracking speed in proportion to the determinant of the Jacobian) in comparison to constant-speed path tracking. This is done first via simulations, with a simple planar manipulator and then with a six-DOF manipulator. From the results it becomes apparent that natural-motion path tracking outperforms constant-speed...
A master-slave system has been used to operate a robot. This system is necessary to communicate human intentions to the robot. In this context, we focus on Myo-Electric (ME) potential. In many previous studies, a motor is used as an actuator, and the torque and position are estimated from the ME potential. However joint stiffness, which humans can change, is not considered. It is possible to solve...
A prototype for a walking assistance apparatus for the elderly or motor palsy patients was developed, using a novel spatial parallel link mechanism. The flat steps of the apparatus move in parallel with the ground; the apparatus can support entire leg alignment (including soles) and assist; walking behavior at ankle, knee and hip joints simultaneously. By using a flexible link, constructed of stainless...
In this study, basic research to obtain biomechanical parameters for optimized design of wearable walking assistant robot was presented and discussed in the condition of its application to the dynamic analysis of gait. Numerous studies are being conducted in order to develop intelligent walking assist devices. However, the reliability, effectiveness and durability of such intelligent walking assist...
The Wilmington Robotic Exoskeleton (WREX) is a passive upper limb orthosis powered by elastic bands, designed to assist children with weakness in their upper limbs. Patient studies with the WREX have determined that an external power source would enhance performance of the system. Two actuation schemes were considered: (i) motors in series with springs at the joints, called `Torsional' (ii) motors...
In this project, we have developed virtual haptic simulators that can simulate several kinds of abnormal movements and haptics of the disabled people. In the previous report, we proposed a leg-shaped robot (Leg-Robot) with a Compact MR Fluid Clutch (CMRFC) to establish highly safe human-machine co-existent system, and control methods to realize several kinds of abnormal symptoms. In this paper, we...
Rehabilitation Robot is a typical man-machine cooperation robot, which can drive the affected limbs to carry out various motor function recovery trainings within the same workspace of patients. To ensure the safety and comfort of the affected limbs during the training process, the system controller is designed based on the impedance control principle, thus the controller can make the robot has a certain...
This paper discusses the design of a Redundant Drive Joint with Double Actuation (RDJ-DA) to produce controlled compliant motions over a higher bandwidth. First, our strategies on mechanical and controller designs to produce compliant motions are described, and the basic structure and impedance control of the RDJ-DA with internal serial structure explained. The standard form of the basic structure...
This paper presents the control architecture and preliminary experimental results of a high performance parallel robot used for ankle rehabilitation. The goal of this work was to design suitable control algorithms for diagnostic, training and rehabilitation of the ankle in presence of musculoskeletal injuries. A position control scheme is used for patient-passive exercises while an admittance control...
Recently, doctor and medical care persons are shortage by the aging of population. Thus, robot support systems are needed for medical care. The motion of the human support system is controlled by routine. Position control and velocity control is usual method. These controls are not considered the human motion. This paper proposes method of human support system using motion coping system. The motion...
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