應用IMU感測器與人體下肢動態分析

毛明煦(Ming-Hsu Mao)

指導教授 ： 楊智媖

國立中正大學/工學院/機械工程學系/碩士(2014年)

摘要

本論文研究目的為建立估測人體下肢的力量分析系統。現有的人體下肢力量分析系統，主要為利用逆動力學，結合測力板所得知之足部與地面間之反作用力，推算人體下肢各關節的受力大小與力矩。然而，測力板之價格昂貴，且測力板舖設範圍將限制量測空間，以致此系統並不適用於較大範圍的行走。為改善量測之便利性，且降低量測評估之儀器成本，本研究提出不用測力板的力量分析系統。首先，將人體雙腳等效於兩個三連桿(大腿、小腿、足部)的機械手臂的運動模型，並利用陀螺儀、加速度計擷取人體運動姿態變化，再以牛頓-尤拉法推導分析人體下肢各肢段的角速度、角加速度及加速度後，利用力平衡與力矩平衡計算得知人體下肢各關節的受力與力矩。最後，將足部受力情形的結果與腳底荷重元測得之反作用力對照比較，以驗證系統之正確性與可行性。同時，將動作擷取系統之運動資訊，以動畫呈現人體行走姿態變化。分析所得之各關節受力、力矩，可提供步態分析所需之完整資訊，並做為研究人工關節或下肢輔具之依據。

關鍵字

關節力矩 ； 關節受力 ； 動作擷取 ； 下肢肢段

並列摘要

This study proposes an analysis system for evaluating the intersegmental forces and moments exerted on human lower limbs during walking motion. In existing analysis systems, the ground reaction force exerted on the feet is generally measured using force plates and the intersegmental forces are then estimated based on the inverse dynamics approach. However, force plates are inconvenient and expensive. Accordingly, the present study proposes a new method for evaluating the intersegmental forces and moments exerted on human lower limbs during walking without the need for force plates. In the proposed approach, the legs are modeled as a parallel robot component of two three-link manipulator. The kinematics and dynamics of the leg model are formulated by using Newton-Euler theory based on the posture information obtained by IMU sensors during walking motion, and the intersegmental forces and moments are derived from forces balance equations and moment equilibrium equations. The results obtained from the analysis system for the intersegmental forces during walking motion are compared with experiment data obtained by using an load cells. It is found that the estimated results are in good agreement with measurement results. Thus, the basic validity of the proposed analysis system is confirmed. Meanwhile, the movement information from motion capture system can be imported to animation simulation system, and use animation simulation system to render the human posture changes during walking motion. The evaluaion forces and moments in joints can provide complete information of the desired gait analysis, and as design reference for artificial joint or leg assistive device .

參考文獻

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