應用於球拍拉線機之數位嵌入式直流無刷馬達驅動系統

Digitally Embedded DC Brushless Motor Drive System for Stringing Machines

本論文研發專用於電子式球拍拉線機的直流無刷馬達驅動系統，以Microchip公司型號dsPIC30F4011的微處理器為基礎，設計嵌入式全數位化的軟、硬體架構，以整合介面電路、感測電路和馬達伺服驅動電路，達成球拍穿線拉力精密控制。首先發展強健式拉力控制法則，以克服拉線系統的各種不確定干擾，包括不同拍線剛度的變化和拉線機構的非線性摩差力，所發展的控制法則可以增加拉線拉力的精度，並克服馬達電流振盪的問題。以3臂MOSFET為架構，利用霍爾元件偵測馬達軸電氣角，設計以PWM訊號控制方式之直流無刷馬達驅動器，並設計保護線路使此驅動器能承受大的拉線電流和馬達瞬間正、反轉所產生之反電動勢。嵌入式微處理機內建有許多功能模組，將透過軟體撰寫以取代A/D、PWM、編碼器解碼和雜訊濾波等外部電路，以減少電路板上電子元件個數，達到全數位化目的。最後，透過實際的拉線拉力實驗，已驗證本文所提方法的有效性。

This paper describes the development of a digitally embedded DC brushless motor drive system for use in stringing machines. A microchip dsPIC30F4011 microprocessor, interface circuit, force measurement circuit, and DC brushless motor driver were integrated in a drive system to enable comprehensive and precise stringing force control. A robust force control law was derived toovercome the disturbance resulting from the variations in string stiffness and nonlinear frictions. Implementing the proposed control scheme enhances the accuracy of the stringing force andsolves the motor current oscillation problem. Hall-effect position sensors were used to detect the electrical angle of the DC brushless motor. A PWM signal control was applied to the motor driver in thethree-phase MOSFET bridge. A protection circuit was designed to withstand a large stringing current and overcome the back EMF caused by shutting down the motor. Using the numerous built-in functions of the microcontroller, a program was developed as a substitute for the external circuits of the stringing system, involving A/D, PWM generators, decoded circuits of encoders, and noise-rejected circuits. The embedded system featured an all-digital design, simplifying the electrical circuit of the proposed system. Finally, experiments were performed using a practice stringing machine to demonstrate the effectiveness of the proposed control methodology.