手機相機光學防手震系統控制系統設計與實驗驗證

Abstract

本論文提出一應用於手機相機之光學防手震系統的系統設計與實驗驗證，手機相機光學防手震技術為在拍攝時，藉由微型制動器使鏡頭移動進行補償以提升拍攝影像之清晰銳利，目前多數手機相機之光學防手震系統之微制動器均採用音圈馬達技術。本控制設計使用兩軸平移式手機相機光學防手震系統，霍爾感測元件量測位移量，由音圈馬達微致動器來控制鏡片的平移位置。整個研究可分成三大部份：光學防手震系統分析、控制系統設計與實驗驗證。第一部份將一光學防手震系統作為受控目標進行實驗，以頻率響應分析儀量測波德圖與運動方程式分析系統。第二部份進行光學防手震系統之相位超前控制系統設計。第三部份為控制系統的模擬與實驗驗證，經由電腦軟體模擬與實驗來驗證控制器之功效後，再經由實際的電路來建立系統。以FPGA實現光學防手震系統之控制，控制能力達到0.1秒內的安定時間，優於以往研究提出的0.2秒安定時間，穩態誤差小於1%，且在5 ~ 20 Hz持續震動下鏡片震動訊號可降低至20 ~ 35%，抑制手震小於10 ~ 30 μm。

關鍵字：光學防手震、音圈馬達、相位超前控制。

This study has proposed a design and experimental verification of the Optical Image Stabilizer (OIS) in a camera phone towards anti-handshake. The OIS technology of mobile phone cameras enhances the clearness and sharpness of the images by using a micro-actuator to move the lens for compensation when taking photos. Currently, the micro-actuators of the OIS system used in mobile phone cameras are mainly based on the Voice Coil Motor (VCM) technology. In this study, the control design uses the two-axis translational OIS, Hall sensors measure the displacement, and also uses a VCM micro-actuator to control the translational position of the lens. The whole study can be divided into three parts: the analysis of an OIS system, the control system design, and the experimental verification. In the first part, an OIS system is taken as a controlled target for the experiment, and the frequency response analyzer is used to measure the Bode plot and the analysis system of the equations of motion. Further, the second part is to conduct the phase-lead controller design of the OIS system. Lastly, the third part is the simulation of the controller and the experimental verification. After verifying the effectiveness of the controller through the MATLAB simulation and the experiment, the system can be built with the actual circuit. The control ability of the OIS system realized by FPGA can make the settling time be less than 0.1 second, which is better than the settling time around 0.2 seconds in previous studies, with a steady-state error less than 1%. Moreover, the OIS system can reduce the amount of movement to 20-35% averagely at 5-20 Hz, and with reduce vibration less than 10-30 μm.

Keywords: Optical image stabilizer (OIS), voice coil motor (VCM), phase-lead control.