Stroke is the leading cause of long-term disability in the world. It causes chronic deficits, such as hemiparesis, especially prevalent in the distal upper extremities. An electro-mechanically driven hand orthosis has been developed to assess the potential thera-peutic use of such devices in rehabilitating hand function. A small Direct Current (DC) brushed motor is used as the main actuator, and a cable-driven glove connected to the motor shaft is the central component of the device. The orthosis control is achieved through a force feedback loop using a miniature load cell attached in series to the cable and control module. The later, generates Pulse Width Modulated (PWM) and direction signals required to drive the motor. The speed is determined by the duty cycle of the PWM signal while the direction by the status of a flag bit modified by a user-operated switch. A portable design was achieved by using a 6 V battery pack as the power supply. The device is ready for use in clinical trials with stroke survivor subjects as it has already been tested on healthy individuals with satisfactory per-formance.

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The subject of the invention concerns an exoskeletal system with: an exoskeletal weight-bearing structure composed of a reference structure and at least one mechanical segment, resources for acquiring movements and movement intentions, composed of resources for time related measurement of the effort coming from at least one biological segment and time-dependent resources for detecting the direction of the movements or movement intentions of these segments, resources for acquiring the spatial position of the mechanical segments in relation to the reference structure, operating resources providing the motor-power for the articulated mechanical segments, and control resources connected at their inputs to the movement and position acquisition resources, and at their outputs to the operating resources in order to control them.

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Using CMU actuators, a Prototype of Mechanical Assistance Device for the Wrist’s Flexion Movement (PMA) was developed and probed in a mechanical model, in order to be implemented in a future as a dynamic powered orthosis or as a rehabilitation assistant instrument. Two Mayor Actuators conformed by three CMU actuators arranged in a series configuration, allows to an artificial hand to be placed in four predefined positions: 0°, 20°, 40° and 60°. The synchronism and control of the actuators is achieved with the Programmable Control Module (PCM). It is capable to drive up to six CMU actuators, and possess two different modes of execution: a Manual mode and an Exercise mode. In the Manual Mode, the position of the hand responds directly to the commands of the keyboard of the front panel, and in the Exercise mode, the hand realizes a repetitive and programmed movement. The prototype was tested in 100 positions in the Manual Mode and for 225 works cycles in the Exercise Mode. The relative repetition error was less than 5% for both test. This prototype only consumes 4,15W, which makes it possible to be powered by small rechargeable batteries, allowing its use as a portable device.

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