Chronic hand impairment is common following stroke. This paper presents an actuated thumb exoskeleton (ATX) to facilitate research in hand rehabilitation therapy. The ATX presented in this work permits independent bi-directional actuation in each of the 5 degrees-of-freedom (DOF) of the thumb using a mechanism that has 5 active DOF and 3 passive DOF. The ATX is able to provide considerable joint torques for the user while still allowing backdrivability through flexible shaft transmission. A prototype has been built and experiments were conducted to evaluate the closed-loop position control. Further improvement and future work are discussed.

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Due to aging of the population, growing numbers of people are affected by impairments of their motor system, caused by disorders like stroke. Treatment of stroke patients is very intensive in the amount of training per patient per day. The treatment duration per patient combined with the total number of people suffering from a stroke makes rehabilitation therapy extremely costly. This makes devices that could reduce the costs of therapy attractive to rehabilitation centres. Currently there are robotic rehabilitation devices under development for both the upper and lower extremities. Our group focuses mainly on the recovery of gait after stroke. The LOPES robot is designed for use in training on a treadmill to accommodate for limited space of rehabilitation centres and easy access for the therapist to the patient. As a ‘robotic therapist’ it is meant to make rehabilitation more effective for patients and less demanding for therapists.

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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

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Parallel robots find many applications in human-systems interaction, medical robots, rehabilitation, exoskeletons, to name a few. These applications are characterized by many imperatives, with robust precision and dynamic workspace computation as the two ultimate ones. This paper presents a multi-objective optimum design procedure to 3 degrees of freedom (DOF) parallel robots with regards to four optimality criteria: workspace boundary, transmission quality index, stiffness. A kinematic optimization was performed to maximize the workspace of the parallel robot. In order to perform an optimal design of 3 DOF parallel robots, an objective function was developed first, and then Genetic Algorithms applied in order to optimize the objective function. The experimental results demonstrate the advantages of the presented optimization procedure in design of 3 DOF parallel robots, specifically TRIGLIDE and DELTA robots. These advantages are reflected in a presented framework for robust, precise, and dynamically calculated workspace boundaries. Therefore, the performances of the 3 DOF translation parallel robots provide high potential and good prospects for their practical implementation in human-systems interaction.

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The design of a wearable upper extremity therapy robot RUPERT IVtrade (Robotic Upper Extremity Repetitive Trainer) device is presented. It is designed to assist in repetitive therapy tasks related to activities of daily living which has been advocated for being more effective for functional recovery. RUPERTtrade has five actuated degrees of freedom driven by compliant and safe pneumatic muscle actuators (PMA) assisting shoulder elevation, humeral external rotation, elbow extension, forearm supination and wrist/hand extension. The device is designed to extend the arm and move in a 3D space with no gravity compensation, which is a natural setting for practicing day-to-day activities. Because the device is wearable and lightweight, the device is very portable; it can be worn standing or sitting for performing therapy tasks that better mimic activities of daily living. A closed-loop controller combining a PID-based feedback controller and a iterative learning controller (ILC)-based feedforward controller is proposed for RUPERT for passive repetitive task training. This type of control aids in overcoming the highly nonlinear nature of the plant under control, and also helps in adapting easily to different subjects for performing different tasks. The system was tested on two able-bodied subjects to evaluate its performance.

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