We are attempting to develop therapeutic technology that individuals with substantial arm weakness and minimal hand function after stroke can use to improve their movement ability without the continuous presence of a rehabilitation therapist. We have developed a device called Therapy WREX (T-WREX) that is comprised of four main features: 1) a passive, gravity-balancing arm support (based on WREX ¿Wilmington Robotic Exoskeleton) that allows a wide range of arm motion 2) a grip sensor that detects even trace amounts of grasp 3) virtual reality exercises that simulate activities of daily living, and 4) software that provides feedback about task performance. Initial clinical testing indicates that chronic stroke patients can significantly improve their movement ability with T-WREX. We have also found that patients strongly prefer using T-WREX for therapy compared to conventional, self-directed, tabletop exercises. This paper reports the results of a follow-up survey conducted with 11 subjects to gain further understanding about the basis for this preference. The results suggest that subjects prefer T-WREX because it is more interesting, and because it allows them to be more successful with their movement attempts. Further, each of the four features of TWREX had significant value to the subjects, suggesting that their combination is synergistic.

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Rehabilitation robotics is an active area of research in the field of stroke rehabilitation. There is significant potential for improving the current physical rehabilitation methods after stroke through the use of robotic devices. RUPERT is a wearable roboticexoskeleton powered by pneumatic muscle actuators. An adaptive robot control strategy combining a PID-based feedback controller and an Iterative Learning Controller (ILC) is proposed for performing passive reaching tasks. Additionally, a fuzzy rule-base for estimating the learning rate for the ILC is also proposed. The proposed control scheme has the ability to adapt to different subject for performing different reaching tasks. The preliminary results from two able-bodied subjects demonstrate that the proposed controller can provide consistent performance for different subjects performing different reaching tasks.

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Upper limbs of human beings are extremely special and significant, which obtain crucial function to achieve manipulations intelligently and dexterously. Gesture-Changeable Under-Actuated (GCUA) grasping function is presented to improve the capability of robotic hands to achieve humanoid manipulations with low dependence on control and sensor feedback systems, which includes tradi-tional under-actuated (UA) grasping motion and special prebending (PB) motion. Based on GCUA function, GCUA Hand II is developed, which has 5 fingers and 14 DOF. All the fingers use similar tendon mechanisms and motors to achieve GCUA function. With GCUA Hand II, a humanoid robot upper limb system is designed, which has two 3-DOF arms actuated by stepper motors and two 14-DOF hands actuated by DC motors. The control system includes four parts: a computer, a FPGA motion controller, a driver module, and a user module, which can control the upper limb system to do various movements dexterously and exactly. With C++ language, a spatial motion program is designed to assist researchers to determine spatial motions of the upper limb system. This system has a great prospect in the field of rehabilitation engineering, extremely environmental manipulation, humanoid robotics and social services.

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In teleoperation, force feedback is essential in making the operator to feel the same force as the slave robot for precise control with unknown environments. A new concept of the exoskeleton type master-arm is introduced. Basically, this master-arm is composed of serial links. To provide maximum range of human motion, several redundant joints are added to the serial links. Intensive graphic simulation was performed to get the optimal design parameters. In order to reduce the number of necessary joint measurement, kinematics of serial links was carefully considered in design. Three measurable, controllable joints and three free redundant joints were used for shoulder axis similar to wrist axis while one measurable, controllable axis was used for the elbow joint. For force feedback, the electric break constraints the joint movement so that the operator can feel the same force as the slave robot does. Calibration algorithm was derived to compensate the variation of the kinematic parameters. The master-arm can be used for teleoperation with a slave robot, or as a motion planner for an industrial robot

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One of the principal guidelines in the design of haptic devices is to provide a suitable mechanical design that can improve control performance and the force-feedback fidelity. Unfortunately these guidelines may conflict with other design objectives (reflected mass, balancing, dexterity) as well as with specifications given by users and applications. For haptic interfaces based on tendon driven actuation it is highly important to achieve an accurate model of friction losses in the transmission system, in order to be able to compensate for them through an active control. In this paper it is reported a method for modeling and control complex tendon transmissions used for driving haptic devices and robots. The presented approach can operate in realtime with very low complexity; it is applicable to all kinds of serial manipulators and provides enough flexibility to allow identification of parameters and modeling of distributed friction phenomena all along the transmission. The approach has been implemented and tested on a 4 DOF exoskeleton system, the PERCRO L-EXOS.

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