線性步進馬達之伺服控制

Abstract

線性步進馬達的氣隙不固定，且馬達被驅動時氣隙會不斷地變化，而導致系統參數快速變動。針對此系統，本文利用共能原理推導線性步進馬達的數學模型，且以電感及反電動勢的量測結果簡化數學模型，再將模型轉換至d-q座標下以利控制器的設計。此外，本文以適應控制法設計電流、速度及位置控制器，除了能夠估測參數外，還能確保電流、速度和位置誤差的收斂性。從實驗結果可知，適應控制法具有良好的穩健性及干擾抑制能力，尤其在參數變動快速的系統中，比傳統的控制法更能達到控制要求，且承受負載時亦能達到定位的效果。

For a linear stepping motor with an air bearing, the air gap between the forcer and the stator is maintained by the pressure generated by the air bearing. As the winding current varies, the changing electromagnetic forces cause the air gap to fluctuate continuously. As a result, the parameters of the linear stepping motor also vary rapidly. In this thesis, the model of a linear stepping motor is derived by using the coenergy method. This model is further simplified and transformed to the d-q frame to facilitate controller design. Then, a nonlinear adaptive control method is developed for the control of the current, the velocity and the position of the linear stepping motor. This method guarantees the parameter estimation as well as the asymptotic convergence of the command tracking error. Experimental results aslo show that this method is very robust when the disturbance loads is present.