This paper presents a new exoskeleton with 4 degrees of freedom (DOF) for index finger rehabilitation. The device can generate bi-directional movement for all joints of the finger through cable transmission, which is required for passive and active trainings. With two prismatic kinematic joints in the design, it can accommodate to some extent variety of hand sizes. The kinematic relation between the device joint angles and the corresponding finger joint angles is simple which greatly simplifies the high level motion control. As the motor capability of patients may be different and the range of motion of the finger may change along with the rehabilitation progress, it is important to take the changes into consideration. And the preliminary experiment has shown that the proposed device is capable of accommodating to these varieties.

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This study explores the feasibility of a hybrid system of exoskeletal bracing and multichannel functional electrical stimulation (FES) to facilitate standing, walking, and stair climbing after spinal cord injury (SCI). The orthotic components consist of electromechanical joints that lock and unlock automatically to provide upright stability and free movement powered by FES. Preliminary results from a prototype device on nondisabled and SCI volunteers are presented. A novel variable coupling hip-reciprocating mechanism either acts as a standard reciprocating gait orthosis or allows each hip to independently lock or rotate freely. Rotary actuators at each hip are configured in a closed hydraulic circuit and regulated by a finite state postural controller based on real-time sensor information. The knee mechanism locks during stance to prevent collapse and unlocks during swing, while the ankle is constrained to move in the sagittal plane under FES-only control. The trunk is fixed in a rigid corset, and new ankle and trunk mechanisms are under development. Because the exoskeletal control mechanisms were built from off-the-shelf components, weight and cosmesis specifications for clinical use have not been met, although the power requirements are low enough to provide more than 4 hours of continuous operation with standard camcorder batteries.

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