Robotic rehabilitation and assessment of the human upper-limb following stroke is currently limited in part by the inability of robots to replicate natural motion. In particular, motion of the shoulder girdle is usually neglected, despite the fact that the shoulder girdle is necessary to stabilize and orient the upper-limb during activities of daily living. Without direct control of the shoulder girdle, it is not possible to monitor or prevent a patient from making compensa-tory movements, which inhibits functional recovery, nor is there a means to properly regain strength and coordination. The more the robot is able to realistically mimic upper-limb motion, the more able the robot will be to assist with true functional movement training, which gives the patient the best chance of motor recovery. To address this issue, a new adjustable robotic exoskeleton called MEDARM is proposed for rehabi-litation and assessment of the shoulder complex. MEDARM provides independent control of six degrees of freedom of the upper-limb: two at the sternoclavicular joint, three at the glenohumeral joint and one at the elbow. A key design feature of the new robot is an innovative curved track mechanism actuated by a cable-drive transmission system. To facilitate a performance evaluation of this new mechanism, a planar version of MEDARM was designed. A full prototype of this planar robot was constructed and several fundamen-tal metrics, including friction, inertia, and compliance, were used to test its mechanical performance. Additionally, the functionality of the robot was examined using preliminary data recorded during a stan-dard reaching task, and by implementing some basic rehabilitation algorithms. This thesis describes the design of MEDARM and its planar counterpart in detail and the performance evaluation of the prototype is presented.

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A system and method are presented to provide assist to a user by means of an exoskeleton with a controller capable of making the exoskeleton display active impedance. The exoskeleton assists the user by reducing the muscle effort required by the user to move his or her extremities. In one embodiment, a single-degree-of-freedom (1-DOF) exoskeleton assists a user with single-joint movement using an active impedance controller. In another embodiment, a multiple-degree-of-freedom (multi-DOF) exoskeleton assists a user with multiple-joint movement using an active impedance controller.

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Robotic exoskeletons are wearable robots coupled to the human body, being the human an integral part of the human-robot system. Specifically, the control plays an important role, and stability must be guarantee. Both actors form a close loop with two control systems interacting dynamically. In this regard, a relevant issue is to understand how humans and robots could physically (kinesthetically) interact and communicate better. This paper deeps in the control of systems interacting dynamically and presents an analytical discussion on the controller design for exoskeletons and the coupled stability problem. Finally, a particular study is described in order to demonstrate the human cognitive system adapting under functional compensation of tremor.

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A motion assistance device has a biological signal detection means for detecting a biological signal from the wearer of the device; a motion assistance device installation member having a drive source for applying torque acting to the wearer by use of each joint of the wearer as a rotating shaft; a control means for controlling the drive source to generate torque corresponding to the biological signal detected by the biological signal detection mean; a drive torque estimation means for estimating the drive torque generated by the drive source; a joint angle detection means for detecting angular displacement of a joint; and a parameter identification means for substituting the drive torque estimated by the drive torque estimation means and the angular displacement detected by the joint angle detection means into an equation of motion to specify the wearer-specific dynamics parameter, the equation relating to the entire system and including wearer-specific dynamics parameter. The control means controls the drive source according to a predetermined control method, based on the equation of motion into which the dynamics parameter identified by the parameter identification means is substituted.

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An adjustable Robotic Tendon is a spring based linear actuator in which the properties of a spring are crucial to its successful use in a gait assistance device. Like its human analog, the adjustable Robotic Tendon uses its inherent elastic nature to both reduce peak power and energy requirements for its motor. In the ideal example, peak power required of the motor for ankle gait is reduced from 250W to just 81W. In addition, ideal energy requirements are reduced from nearly 36 Joules to just 25 Joules per step. Using this approach, an initial prototype is expected to provide 100% of the power and energy neccessary for ankle gait in a compact 0.84kg package. This weight is 8 times less than that predicted for an equivalent direct drive approach.

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