An Exoskeleton Robot for Human Forearm and Wrist Motion Assist -Hardware Design and EMG-Based Controller

Abstract

The exoskeleton robot is worn by the human operator as an orthotic device. Its joints and links correspond to those of the human body. The same system operated in different modes can be used for different fundamental applications; a human-amplifier, haptic interface, rehabilitation device and assistive device sharing a portion of the external load with the operator. We have been developing exoskeleton robots for assisting the motion of physically weak individuals such as elderly or slightly disabled in daily life. In this paper, we propose a three degree of freedom (3DOF) exoskeleton robot (W-EXOS) for the forearm pronation/ supination motion, wrist flexion/extension motion and ulnar/radial deviation. The paper describes the wrist anatomy toward the development of the exoskeleton robot, the hardware design of the exoskeleton robot and EMG-based control method. The skin surface electromyographic (EMG) signals of muscles in forearm of the exoskeletons' user and the hand force/forearm torque are used as input information for the controller. By applying the skin surface EMG signals as main input signals to the controller, automatic control of the robot can be realized without manipulating any other equipment. Fuzzy control method has been applied to realize the natural and flexible motion assist. Experiments have been performed to evaluate the proposed exoskeleton robot and its control method.

Design and Implementation of a Compact Master-Slave Robotic System with Force Feedback and Energy Recycling

“…Besides, it is extremely difficult to mount sensors in microenvironments. W-EXOS (12) was an exoskeleton robot developed for assisting forearm and wrist motions of physically weak patients. Based on the individuals' motion intention, the robot can deliver assistance for users to perform motions of forearm pronation/supination， wrist flexion/extension and ulnar/radial deviation smoothly and naturally.…”

Energy Wave Transmission and Control Analysis in Force Reflection Teleoperation Based on Interconnected Power Line

“…In the medical robot system, W-EXOS is a successful exoskeleton robot for assisting frail patients to move their forearm and wrist [9], which can assist users to complete internal/external rotation movement of their forearm and bending, stretching and deviation movement of wrist, but a three-axis force sensor and two torque sensors are needed to measure the information. Ueki develops a supplementary robot for rehabilitation of single hand [10].…”

RobHand: A Hand Exoskeleton With Real-Time EMG-Driven Embedded Control. Quantifying Hand Gesture Recognition Delays for Bilateral Rehabilitation

“…The advantage of using classifier algorithms and pattern recognition instead of non-pattern recognition methods is the possibility of determining numerous predefined hand gestures, which allows for complete and accurate position control because different types of grasping can be distinguished. However, determining multiples types of grasping requires numerous electrodes [45], [46], [47], [48], [49], [50], [51], and most of the sEMG-based pattern recognition techniques proposed in the literature are not applicable in practical cases because they require a hand exoskeleton with a large number of DoFs and high computational requirements, which cannot be supported by real-time embedded systems [52], [53].…”