Design and realization of personal computer-based continuous passive motion device to prevent shoulder joint stiffness

The design and realization of a PC-based continuous passive motion device (CPM) for shoulder joint recovery was done. This machine can be used after performing an operation, or for patients suffering from joint motion limitation due to early stage of frozen shoulder. The system consists of a PC, a 8255, a motor driver and stepper motor, an application software, a mechanical module and a forearm orthotic. The experimental results showed that pulse signals are able to control the motor driver which in turn controls the stepper motor according to the predetermined parameters. The stepper motor is also able to provide bi-directional motions at the predetermined durations and velocities (low, medium, and high). By adjusting the delay time in the software, the PC-Based CPM can produce smooth motion.