A low cost parallel robot and trajectory optimization method for wrist and forearm rehabilitation using the Wii

A robot called the Closed-chain Robot for Assisting in Manual Exercise and Rehabilitation (CRAMER) was developed to assist impaired persons in making three degree-of-freedom movements of the forearm and wrist (forearm supination/pronation, wrist flexion/extension, and wrist ulnar/radial deviation). With a parts and machining cost of less than 1500, this robot was designed to be inexpensive by using a simple parallel mechanism design and off-the-shelf hobby servomotors. CRAMER is intended to engage patients in their rehabilitation therapy by having them play computer-based exercise games. Toward this goal, the remote for Nintendopsilas Wii was integrated into the handle of the robot in an attempt to allow patients to play the high-quality yet affordable motion-based games that have been developed for the Wii. A framework for planning robot joint trajectories capable of generating desired accelerometer measurements used by Wii games was developed using function optimization techniques. Results of a preliminary experiment with the bowling and golf games of Wii Sports show the feasibility of playing Wii using robot-assisted wrist movements. However, to make this approach clinically practical, an improved software communication with the Wii would be necessary.