Robot-assisted rehabilitation is an active area of research in the field of stroke rehabilitation. RUPERT is a wearable roboticexoskeleton powered by pneumatic muscle actuators. In this study, we described the structure of the controllers for the five degrees of freedom currently used by RUPERT. We applied the RUPERT on 6 stroke patients to provide robot-assisted rehabilitation therapy in a clinical study. Statistical χ² test on the proportion of successfully reaching targets showed that 3 out of the 6 patients demonstrated significant improvement in reaching targets successfully, and the remaining 3 did not show performance improvement or deterioration. We plan to implement the RUPERT in the patient’s house for easier access and more frequent use. More significant performance results are expected.

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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 series with gravity balancing elastic bands, called `In-line’. Dynamic models of these two motor placements were developed. Dynamic simulations, based on representative patient motion data, were performed. We observed that the torsional case with motors in series with springs at the joints required substantially less torque when compared to the in-line case with motors in series with gravity balancing springs. An experimental platform is being developed with this configuration and preliminary results are included.

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The main aim of this paper is to design a hybrid force-position controller using fuzzy logic (FL) for the robotic arm of a 9 degrees of freedom (DOF) upper limb wearable exoskeleton rehabilitation robot. The robot is designed and built in our lab for assisting in the rehabilitation of patients post-stroke. The robotic arm of the rehabilitation robot is driven by pneumatic muscles (PM) and its dynamic performance is very complex. Fuzzy logic (FL) control techniques are applied to the robotic arm and the results show that FL controller shows better performances than that of the conventional PI controller in hybrid force-position control of the specified robotic arm of the rehabilitation robot.

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The design of robots required to work in the close vicinity or physically interact with humans such as humanoids machines, rehabilitation or human performance augmentation systems should not follow the traditional design rule `stiffer is better’. Safety is a particularly vital concern in these systems and to maximize it a different design approach should be used. The role of compliance in improving specific suspects of the robotic system, including safety and energy efficiency, has been studied and validated in many works. This work presents the design and realization of a new variable compliance actuator for robots physically interacting with humans, e.g. prosthesis devices and exoskeleton augmentation systems. The actuator can independently control the equilibrium position and stiffness using two motors. The main novelty of the proposed variable stiffness actuator is that the stiffness regulation is achieved not through the pretension of the elastic elements which needs the stiffness tuning actuator to act against the forces generated by the springs but by mechanically adjusting the fixation of the spring elements. As a result the stiffness actuator does not need to act against the spring forces reducing the energy required for the stiffness adjustment to minimal.

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Knee ankle foot orthoses are prescribed to provide stability and maintain lower limb joints at their functional position. Current devices provide stability by locking joints permanently during the unsafe phase of a pathological gait (the stance phase). Though stability is obtained with such orthoses, gait patterns are unnatural and non-cosmetic. Other systems adapt more dynamically during gait, applying different strategies to recover or improve mobility. The system presented consist in a wearable set of sensors, actuators at knee and ankle joints, and a control and monitoring ambulatory unit, all integrated in a custom designed knee-ankle-foot robotic exoskeleton. A base unit allows wireless communication of the ambulatory unit, trough a Bluetooth link, with a PC software platform conceived for on-line and off-line data evaluation. Sensors adapted to the mechanical frame of the orthosis collect kinematics, such as angles at knee and ankle joints, and angular positions and accelerations at lower limb segments; kinetics, such as forces at the orthosis rods and fixation parts, and also foot contact information.

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