高精密度雙軸鐵心式永磁同步伺服線性馬達定位平台之控制器設計與性能分析

Abstract

本研究提出了適應性增量式滑動模式控制(AISMC)應用於雙軸式的鐵心式永磁伺服同步線性馬達，以建立高精密度之雙軸運動控制平台。AISMC之特色為在設計時會考慮過去的控制量輸入以降低滑動模式控制(SMC)的抖振現象，以及利用適應控制來即時估測與補償系統的不確定項，以達到提升系統精確度之目的。 為了建立出高精密度之雙軸運動平台，本研究會先運用磁場導向定理(field-orented control)將驅動馬達之三項控制電流轉換為d-q軸控制電流，並將其與線性馬達之磁推力方程式和機械模型整合後得出雙軸線性馬達平台的動態方程式。然而在馬達運作中會遭遇到許多外在干擾，諸如摩擦力、漣波效應及系統內部參數之變異量等，我們將這些干擾統稱為系統的不確定項並將其納入雙軸線性馬達平台的動態方程式內做考量，以建立出較為精細的動態方程式。依據上述所建立之系統動態方程式便可設計出高階控制器，在控制器設計階段我們會先設計SMC，由於其結構簡單和強健性高因此很適合用於線性馬達這類系統不確定性較多的系統中，但其缺點為在順滑模態時的抖振現象，為改善此現象我們設計了AISMC，其特色為在設計控制器時會考慮過去的控制量輸入，藉此抑制抖振現象，並利用適應控制來補償系統的不確定性，以提升雙軸運動平台之精密度。 在實驗階段我們會先分別對X軸與Y軸做獨立控制，以分析出SMC及依照其缺點來改良之AISMC的效能差異，透過定位控制及追跡控制之實驗結果分析可發現AISMC可有效的抑制抖振現象並且擁有較高的精確度，因此在雙軸同動追圓之實驗中我們便採用AISMC作為主要之控制器。In this research, we proposed an adaptive incremental sliding mode control(AISMC) to achieve a two-axis high precision motion control platform. The features of AISMC are considering previous control action to reduce chattering phenomenon from sliding mode control(SMC) and compensating system uncertainties instantly to increase system accuracy by adaptive control. To establish a two-axis high precision motion control platform, we will transfer three phase control currents to d-q axis control currents by field-oriented control, then integrate electromagnetic force of linear motor with mechanical model to get system dynamic equation of the two-axis linear motor platform. The linear motor will suffer some external disturbances during working such like friction force, ripple force and system uncertainties. We will integrate those disturbances, like system uncertainties, and consider them in the system dynamic equation of two-axis linear motor platform. Then, the controller design will be based on the system dynamic equation. Frist, we design SMC, its simple structure and high robustness are quite suitable for linear motors which have many system uncertainties. However, the disadvantage of SMC is chattering phenomenon, and AISMC is designed to overcome it. The characteristics of AISMC are taking previous control action into account to suppress chattering phenomenon, and compensating system uncertainties by adaptive control to enhance precision accuracy of two-axis high precision motion control platform. In experimental section, first the X axis and Y axis will be experimented separately to analyze the performance of SMC and AISMC. According to the experimental results of position control and tracking control, AISMC has better precision accuracy and is able to suppress chattering phenomenon. On the basis of above experimental results, we choose AISMC to be the main controller of the two-axis high precision motion control platform for tracking circle trajectory.