微型線性對焦與光學影像穩定致動器之適應性模糊順滑模態控制

Abstract

近年來，攝影者對相機高畫素的要求愈來愈高，且應用在手機相機裝置的體積愈來愈小，所以相機系統朝向高畫素、微型化與輕薄化的發展趨勢愈來愈明確，使得對焦與光學影像穩定致動器的設計與精密定位控制成為值得探討與研究的主題。 本研究完成設計快速定位、節能與高效能的對焦致動器，亦完成設計可抑制外部振動產生影像模糊的光學影像穩定致動器。由於必須在有限的狹小空間中裝置微型線性對焦與光學影像穩定致動器，尤其在手機相機或微型相機裝置中更是一大挑戰，所以本研究的光學穩定致動器是採用音圈致動器搭配浮動式影像感測器，故不須對光學補償鏡片進行補償控制，即可達到微型化之目的。 本研究採用的控制演算法結合了PID控制、適應性控制、順滑模態控制、和模糊邏輯控制，利用其控制項的相似性，提出一種合適於微型線性對焦與光學影像穩定致動器之適應性模糊順滑模態控制法則。此控制策略可精確地利用感測器之位置與速度回授訊號來檢知致動器之滑動元件，並快速且精確地補償外部環境或低頻手振所造成的影像模糊。

Recently, photographers demand higher pixel resolution of image sensors and smaller dimension in both digital and mobile phone cameras. The auto–focusing (AF) and anti–shake (AS) functions have thus become interesting research topics. Both techniques can effectively prevent taking camera blurring images by means of compensating camera shakes when photographers take pictures. In this study, linear focusing actuators (LFA) for AF operation and compact optical image stabilization actuators (OISA) for AS functions have been presented. Additionally, because of assembling in restricted space of slim camera devices, voice coil actuators and floating image sensors are collocated in camera systems. They do not require special–purpose compensating lenses for AS functions but can miniaturize systems. In addition, proportional–integral–derivative, adaptive, fuzzy logic, sliding mode control algorithms have been combined to approximate the switching control to minimize chattering. Consequently, the devised adaptive fuzzy sliding mode control law applied in the designed LFA and OISA module can obtain fast dynamic performance and accurate positioning to suppress blurred images, which are caused by external camera shakes in camera systems.