Functional Electrical Stimulation System for Motion Control of Lower and Upper Extremities.

点击翻译按钮获取中文摘要

Restoring behavioral functions of paraplegic or quadriplegic patients who have been suffered from spinal cord injury or brain damage is a great social demands for their everday livings. Functional Electrical Stimulation (FES) is one of the rehabilitation techniques to reconstruct the basic functions since the FES can activate the denerved muscles of the patients. Primary restoration of gait functions of the paraplegic patient was attained by using the FES with open-loop control system and mechanical support system. In order to obtain stable biped gait and standing, however,closed-loop control system is required.In this study, closed-loop control of joint angle and muscle contractile force of lower extremety was carried out on normal human subjects by using the FES with closed-loop control system. The total FES system consisted of micro-computer, electrical stimulator, angle and force sensors, AD converter, DA converter, and electrodes. On the first stage of the study, physiological mec … More hanism of the FES on lower extremity was made clear, and then computer controlled stimulator satisfying high electrical safety was developed. Using the FES system, joint angle controls of ankle and knee were carried out with two PID controllers prepared for both moving directions of flexion and extension. Appendant use of command filter in the controllers provided decrease in overshoot and fluctuation of the controlled angle in the load free state. As for the muscle force control, FES system with PID controller and modulator was used and a good control response was obtained. In order to investigated load effect on the control objects, model reference adaptive control system (MRACS) was used. Similar controlled performances to those of the well designed PID controls were obtained in the load free state. When the load changed, MRACS provided decrease in the oscillatory behavior of the joint angle.In conclusion, it can be stated that the developed FES system with PID controller and command filter as well as MRACS are highly available for the joint angle controls of ankle and knee, and also for the control of muscle contractile force. Practical use for restoration of behavioral functions of paraplegic patients might be available using the FES system in the near future. Less