可切換坐/站姿態的重力平衡下肢外骨骼設計

Design of a gravity-balanced lower limb exoskeleton with switchable sitting/standing stages

吳聖麟(SHENG-LIN WU)

指導教授 ： 陳達仁

國立臺灣大學/工學院/機械工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202102513

摘要

近年來，外骨骼得到了廣泛的應用。其中，被動重力平衡外骨骼對於MMT 2級患者必不可少，重力平衡外骨骼通常以坐、站或坐到站的方式進行。但是沒有一個重力平衡外骨骼執行這3個姿勢。所以這項工作的目的是設計一種下肢重力平衡外骨骼，可以在這三個姿勢下進行髖關節和膝關節的屈伸動作。藉由簡化人體下肢關節求得人體在矢狀面的模型以及人體下肢動作不同自由度以及動作的需求，提出外骨骼的機構構型，可以藉由轉變地桿位置切換動作以及藉由桿件之間的連接切換動作的自由度。接著提出重力平衡的設計，通常重力平衡都使用彈簧消除重力的影響，為了使彈簧可以不必變動太大就可以消除機構每一個姿態的重力影響，加入一些約束到機構之中，使得在切換不同姿態時，只需改變彈簧的一個接點。由重力平衡公式可以求得彈簧參數以及外骨骼重力位能的關係，藉由人體下肢長度決定機構長度後，可以求得彈簧係數。並使用Matlab驗證機構設計的正確性。接著通過肌電圖(EMG)量測，我們可以驗證實體外骨骼的效能。在實驗中，會測量並分析了人體髖關節以及膝關節屈伸相關肌肉(股直肌,股外側肌)之穿戴外骨骼前/穿戴外骨骼後的肌電訊號。結果表明，當人體穿戴被動重力平衡外骨骼，在不同姿勢下，人的股直肌以及股外側肌的肌電訊號都有減少。這代表著人體之下肢肌肉施力的強度有下降，綜上所述，此論文展示了此外骨骼可以減少人體動作施力大小。

關鍵字

外骨骼 ； 姿態 ； 消除重力影響 ； 彈簧 ； 肌電

並列摘要

The exoskeleton has been used widely in recent years. The passive gravity-balanced exoskeleton is essential for MMT (manual muscle training) level 2 patient and the passive gravity-balanced exoskeleton usually performs in sitting, standing or sitting to standing. But there is no gravity-balanced exoskeleton performs with 3 posture. So, the aim of this work is devised a lower limb gravity-balanced exoskeleton can perform hip and knee flexion and extension in sitting and standing posture and can help transform 2 postures. By simplifying the lower limb joints of the human, the human lower limb model in the sagittal plane can be obtained. With human lower limb model and the different degrees of freedom and movement requirements of the lower limbs of the mechanism configuration of the exoskeleton is proposed. This mechanism can be changed different posture by changing the position of the ground link. The degree of freedom of the motion can be changed by connecting the linkages. The design of gravity-balanced exoskeleton is proposed. Generally, the gravity balance uses springs to eliminate the influence of gravity. In order to make the springs not to change too much to eliminate the gravity influence of each posture of the mechanism, some constraints are added to the mechanism, so that when switching between different postures, only one contact point of the spring needs to be changed. The relationships between the spring parameters and the potential energy of the exoskeleton can be obtained from the gravity balance equation. After the length of the body is determined by the length of the lower limbs of the human body, the spring coefficient can be obtained. And use Matlab to verify the correctness of the mechanical design. By, electromyography (EMG) measurement, the performance of the exoskeleton can be obtained. In the experiment, the EMG signal of the human hip and knee joint flexion and extension related muscles (rectus femoris, lateral femoris) before and after wearing the exoskeleton will be measured and verified. The results show that when the human body wears the gravity-balanced exoskeleton, the EMG signal of the human rectus femoris and lateral femoris muscles decreases in different postures. It represents the strength of the muscles of the lower limbs is decreased.

並列關鍵字

Exoskeleton ； stages ； eliminate the gravity influence ； spring ； EMG

參考文獻

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