應用順滑模態控制於微型音圈馬達摩擦力補償之研究

Abstract

本論文提出一順滑模態控制器，用來補償應用於照相手機CCM模組之內嵌導桿微型音圈馬達之非線性摩擦力，以達精密之位置控制。有效的補償線性摩擦力，此音圈馬達就可不需要使用潤滑油，如此便可提升其成本效能與可靠度效能。此音圈馬達之機構全行程僅0.35mm或甚至更短，其非線性摩擦力是一非匹配式的干擾，且其控制精度是微米之要求。使用本論文提出之控制器，再加上對順滑模態之狀態方程式做極點配置，即使在有非匹配式的干擾的情況下，不管穩態誤差之設計目標有多小，皆可達成。至於所提出之控制器之性能，首先搭配一音圈馬達之物理模型，用電腦模擬的方式來驗證，接著用實驗結果來證明所提出之控制器能夠避免傳統PI控制器所導致之stick-slip 震盪。實驗結果亦證明馬達的到位速度與重現性優於一般的規格要求，並且驗證把順滑模態控制器的符號函數換成飽和函數可避免切跳現象。

This thesis presents a sliding mode controller to compensate for the nonlinear friction of mini voice-coil motor (VCM), which is embedded with guide pins, for position control in compact camera module (CCM) application. With the effectiveness of compensating the nonlinear friction, the lubrication oil can be removed from the VCM, and the performance of cost and reliability then can be improved. In the VCM, the actuator’s full stroke is only 0.35mm or less, nonlinear friction force falls into mismatched condition and um-level resolution is required. With the proposed controller, arbitrarily small steady state errors can be achieved by pole placement of the sliding mode state equation. The performance is firstly simulated with a physical VCM model. The experimental results are then presented to demonstrate the proposed controller is able to avoid stick-slip oscillation that usually yields when using a classic controller, such as PI controller. The experimental results also show that the performance of settling time and repeatability is better than nominal requirement and the undesired chattering can be remedied by replacing sign function with saturation function in the proposed control law.