創新步行輔助機構之設計與應用

Abstract

本研究目標在於提出一新型步行輔助機構，使一完整步態週期中達到省力的原則。蒐集被動式輔具相關文獻中，發現重力平衡的設計概念對於省力方面有具體良好的成效，重力平衡(Gravity Balance)原理藉由置入彈簧的方式，能使機構在運作範圍中的任何形態停駐時保持平衡，消除重力對其關節產生的扭矩，以達到運動省力的效果。 本研究以單一兩個自由度機器腳的重力平衡架構為主，首先從步態週期中的支撐期與擺動期推導重力平衡的系統，提出兩種省力的切換方案，第一個方案是藉由滑動切換來滿足完整步態的重力平衡設計，另一種方案則為了改善擺動期彈簧過餘拉伸力問題，運用機構合成設計出一套切換機構改變彈簧固定位置來縮短彈簧長度，以降低彈簧所造成的拉伸力，並從一套足部軌跡設計流程產生出跨步動作，最後以SolidWorks COSMOSMotion模擬來評估本設計之省力效果。

In this paper, we propose an innovative walking assist device for saving energy during a complete walking cycle. After searching literature of passive assist device, we find that using gravity balancing mechanism is a useful concept for saving energy. The gravity balance condition can be achieved by implementing spring. The mechanism can be balanced at arbitrary rest configuration and reduce the torque at joints which is caused by gravity on this condition. Thus, saving energy can be done by using gravity balancing mechanism. A 2-DOF leg mechanism with gravity balance was established. First, we derived the gravity balancing system from support and return phase in a walking cycle. Then, we developed two types of saving energy. First type is using gliding method to achieve gravity balance in a complete walking cycle. Another type is the idea of switching mechanism for adjusting the spring position to shorten spring length and reduce the excess spring force in return phase. This switching mechanism is found by mechanical synthesis. Then, we constructed a process of producing a foot trajectory to simulate a complete walking motion. Finally, we use SolidWorks COSMOSMotion to evaluate the effects of energy saving.