本論文串聯式彈性致動器(Series Elastic Actuator, SEA)使用扭力彈簧串接馬達以及煞車器或機械手臂的結構，並且分別使用在SEA-煞車器及SEA機械手臂硬體上並進行位置控制及扭力控制。
首先針對扭力彈簧進行模型建模，使用編碼器計算出彈簧角度差，並使用扭力計與彈簧角度差做線性回歸，將傳統零階彈簧方程式改成二階彈簧方程式，其目的為在彈簧變形量動態效應有更精確的擬合結果。接著針對SEA-煞車器上進行建模，求出SEA-煞車器負載的參數，並做位置控制的模擬與實驗及扭力控制的模擬與實驗，並使用干擾觀測器對於SEA-煞車器目的為加強控制的強健性。
最後針對SEA機械手臂進行建模，使用尤拉-拉格朗日方程式(Euler-Lagrange equations)求出機械手臂的動力學方程式，並與SEA、馬達模型進行模型合併，得知完整的SEA機械手臂的動力學模型。接著做SEA機械手臂的位置控制及扭力控制模擬及實驗，並使用干擾觀測器對於SEA機械手臂目的為加強控制的強健性。
實驗部分，本論文硬體致動器使用直流馬達，使用美商儀器(NI)的控制器及使用LabVIEW做程式的撰寫。而模擬部分則是使用MATLAB軟體，由推得的動力學做為系統模型，並根據模擬結果找出可收斂的比例-微分-積分控制器參數以此做為實驗架構的基礎。
最後根據位置控制、扭力控制的模擬與實驗結果，觀察出干擾觀測器對於控制結果進行深入的分析並討論。並根據其結果提出干擾觀測器對於系統控制的強健性有顯著的提升，討論出未來可深入研究之方向。

A series elastic actuator (SEA) is an actuator consisting of a motor in series with a torsion spring. A SEA is usually connected with a brake or a robotic arm to achieve position control and torque control.
In this thesis, first, a torsion spring is modeled based on a linear regression, where two encoders are used to calculate the spring deflection and a torque sensor is used to measure the spring torque. In addition, a second-order spring model is proposed to provide accurate fitting results due to the dynamic effect of the spring deflection taken into account. Secondly, the model is applied to a system consisting of a SEA connected with a brake, where the system parameters are determined based on experimental results, and the simulations and experiments of position control and torque control are performed. To enhance the robustness of the control system, a disturbance observer is used to evaluate a disturbance torque. Thirdly, another system consisting of a 3-DOF robotic arm driven by SEAs is modeled, where the Euler-Lagrange equations are used to establish the dynamic equations. Besides, the simulations and experiments of position and torque control are conducted, where two types of disturbance observers are individually designed for position and control.
Regarding to the experimental setup, DC brushed motors are selected to develop SEAs. A controller is implemented by using an embedded system, Compact Rio, manufactured by National Instruments, where the software LabVIEW is used to program the relevant controller codes. The simulations are performed by using the software MATLAB, and the simulation results are the experimental basis of the gains of the proportional-derivative-integral controllers to ensure the convergence of system.
Based on the simulation and experimental results of position control and torque control, the performances of the disturbance observers and the controllers are analyzed and discussed. The results show that the disturbance observers provide significant improvements of robustness in the closed-loop control systems.

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