Design and Control of an Electr ical Assist Wheelchair Pedaled by Paraplegics through Functional Electr ical Stimulation

本研究期間為二年，旨在完成功能性 電刺激踩踏電動輔助復健輪椅之設計與控 制，針對下肢肌肉神經傳導障礙的患者進 行電刺激，前輪又加一個輔助電動馬達， 做為上坡及病患肌肉疲乏時的輔助推動 力，除了能達到週期性的踩踏復健運動， 也能增加復健功能之多樣性與趣味性。系 統控制將依據復健目標調整復健果效控 制，再整合輪椅性能控制，同時兼顧復健 與行動之安全與舒適。另外，因此建立之 完整理論架構提供充分之理論基礎，將可 幫助做有系統的進一步研發之用。 第一年研究提出一結合電刺激肌肉關 節模型與四連桿機構之數學模型來模擬下 肢癱瘓病患電刺激輔助踩踏運動，其中肌 肉關節模型可預測電刺激所引發之關節力 矩，四連桿機構可根據此力矩來模擬電刺 激踩車運動。基於上述之數學模型，我們 施加一由系統模型推演之PID 控制器來完 成病人踩踏運動之速度控制。我們不但要 求控制系統能掌控踩踏速度的動態響應， 也將透過此一數學模型的理論分析與模擬 結果之評估，達成整体系統之設計目標。The objective of this two-year project is to design and control of an electrical assist wheelchair FES pedaling system,. The FES is used to stimulate the paralyzed lower limbs to achieve periodic cycling exercise and a disk motor incorporated into the front wheel will assist the ambulation when the wheelchair is in a up-hill situation, the muscle fatigue sign is on, or the patient simply gets tired. The system in turn will make the patients’ rehabilitation process more versatile and interesting. The system control will integrate the wheelchair performance control and the rehabilitation outcome control according to the goals so that the wheelchair will be able to serve for both rehabilitation and ambulatory purposes. This research will also establish a solid theoretical foundation, which allows for a systematic approach to the further development. A mathematical model, which contains a Hill-type muscle-joint model and a four-bar linkage, is established in this first-year research to simulate FES-assisted pedaling movements for paraplegics. Our muscle-joint model is a modified three-factor model and is used to predict joint moment induced by functional electrical stimulation (FES). And the five-bar linkage is used to simulate pedaling movement as a result of the FES induced moment. Based on this model, we developed a PID control for patient pedaling speed control. It is required that the control should perform the desired system dynamic response. It is also our intention that the system model can be utilized in system analysis and evaluation to achieve asystematic overall system design