手機數位相機光學變焦機構之最佳化設計與控制

Optimal Design and Control of the Mini-zoom Mechanism of Digital Cameras in Mobile Phones

吳松青(Sung-Ching Wu)

指導教授 ： 趙昌博

中原大學/工學院/機械工程研究所/碩士(2006年)

https://doi.org/10.6840/cycu200600870

摘要

本文以光學變焦鏡組(Optical Mini-zoom Lens Unit)之最短定位時間為主要考量並參考目前市售具相機功能手機之尺寸，設計一手機相機光學變焦機構之外型。此光學變焦機構使用音圈馬達(VCM)做為致動器之動力來源，線圈通入電流在由磁石與軛鐵(Yoke)形成之均勻磁場中受勞倫茲力(Lorentz’s Force)移動。經由鏡片組(Lens Unit)在光軸(Optical Axis)方向之移動，使鏡片組間相對位置變化造成成像之縮放。
針對致動器之最短定位時間做機構設計、最佳化設計與最佳化控制。在機構設計之階段，選擇質量較輕之動圈式音圈馬達(Moving-coil Type VCM)，並在致動器上下各使用一組磁路以提升推力並克服致動器移動時之傾斜(Tilt)現象；在最佳化設計階段，將機構尺寸作為最佳化之對象，包含致動器尺寸、線圈圈數、磁石厚度、軛鐵尺寸等，並使用基因演算法(Genetic Algorithm)以靈敏度(Sensitivity)作為性能指標(Performance Index)來求得最佳化之尺寸設計參數。當靈敏度獲得最佳值時，致動器之加速度亦會達到最佳；在最佳化控制的階段，使用最短定位時間控制理論中之Bang-bang Control作為設計控制器之依據，並將最佳化設計階段獲得之致動器最大加速度作為控制輸入，以期獲得最短之定位時間。

關鍵字

光學變焦 ； 掀蓋式手機 ； 音圈馬達 ； 最佳化控制 ； 最佳化設計 ； 基因演算法 ； Bang-bang Control

並列摘要

Optimum design of an optical mini-zoom actuator in a mobile phone is presented in this study. The design is accomplished for the magneto-electro-mechanism via Genetic Algorithm (GA). The actuator mechanism consists of mainly VCM, where there are coils and magnets. The thrust of the optical mini-zoom actuator is from the voice coil motor, VCM. The coils with current on the lens holder actuator are pushed to move by Lorentz’s force in the uniform magnetic field. The images are zoomed by the relative position of lens units which are moving along the optical axis. The purpose of this thesis aimed at the shortest traveling time of actuator and the mechanism design, optimum design and optimal control were proceeded. In the step of mechanism design, the lighter moving-coil type VCM is chosen and two magnetic circuit units are used to increase the thrust and overcome tilting when lens holder actuator is moving. In the step of optimal design, the design variables including the dimensions of actuator, yoke, account of coil, the thickness of magnet and etc are chosen. The genetic algorithm is chosen to be optimal theory and sensitivity is defined to be performance index to obtain the optimal design variables. In the step of optimal control, bang-bang control is chosen as the minimum time control theory in this thesis. The optimal sensitivity obtained via optimal design step can provided maximum acceleration and then use the maximum acceleration to be control input to expect to get the shortest traveling time of actuator.

並列關鍵字

moving-coil type VCM ； sensitivity ； bang-bang control ； mini-zoom ； optimum design ； genetic algorithm ； voice coil motor

參考文獻

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