臺灣博碩士論文加值系統

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。

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.

摘要………………………………………………………………………….…………I
Abstract……………………………………………………………………………..…II
致謝………………………………………………………………………………..…III
Table of Contents…………………………………………………………………….IV
Figure Captions……………………………………………………………………….V
Table Titles……………………………………………..……………………………VII
Nomenclature……………………………………………...……………………….VIII
1. Introduction…………………………………………………………...…………….1
2. Mechanism Design………………………………………………………………….6
2.1 Actuator Structure…………………………………………………………….....6
2.1.1 Lens Holder Actuator………………………………………………………7
2.1.2 Voice Coil Motor…………………………………………………………...8
2.2 Magnetic Circuit Analysis………………………………………………………9
2.2.1 Equivalent Magnetic Circuit……………………………………………….9
2.2.2 Finite Element Model Analysis…………………………………………...15
3. Optimal Design……………………………………………………………………17
3.1 Optimal Design Problem………………………………………………………17
3.2 Define Variables……………………………………………………………….19
3.3 Optimization via Genetic Algorithm…………………………………………..25
4. Preliminary Control………………………………………………………………..27
5. Conclusions and Future Work……………………………………………………..29
References……………………………………………………………………………31
Figures………………………………………………………………………………..33
Tables…………………………………………………………………………………57
簡歷…………………………………………………………………………………..64

Figure Captions
Fig. 1. The design of position for digital camera in mobile phone of Pat. [309756]
Fig. 2. The structure design of Pat. [4678951]
Fig. 3. The structure design of Pat. [5121016]
Fig. 4. The structure design of Pat. [5939804]
Fig. 5. The zoom lens unit design of Pat. [5268793]
Fig. 6. The zoom lens unit design of Pat. [0248854]
Fig. 7. The zoom lens unit design of Pat. [5712733]
Fig. 8. The structure of presented optical mini-zoom actuator
Fig. 9. The front view of lens holder actuator
Fig. 10. The diagram of the Fleming left hand rule
Fig. 11. The diagram of the principle of VCM
Fig. 12(a). The structure profile of the model
Fig. 12(b). The equivalent magnetic circuit diagram of the model
Fig. 12(c). The equivalent circuit diagram of the model
Fig. 13(a). B-H curve
Fig. 13(b). The second quadrant of B-H curve
Fig. 14. The profile of the model and material properties
Fig. 15. The finite element model of the magnetic circuit structure
Fig. 16(a). The magnetic flux of the model
Fig. 16(b). The magnetic flux vector of the model
Fig. 16(c). The magnetic flux density of the model
Fig. 16(d). The magnetic field intensity of the model
Fig. 17(a). The position of plot path
Fig. 17(b). The distribution of magnetic flux density on plot path
Fig. 18(a). The position of the three plot paths
Fig. 18(b). The distribution of magnetic flux density on the upper plot path
Fig. 18(c). The distribution of magnetic flux density on the middle plot path
Fig. 18(d). The distribution of magnetic flux density on the bottom plot path
Fig. 19(a). The structure of actuator
Fig. 19(b). The front view of lens holder actuator with variables
Fig. 19(c). The profile of magnetic circuit structure with variables
Fig. 20. A flow chart of a genetic algorithm
Fig. 21. GA optimal process
Fig. 22. numerical result of bang-bang control

Table Titles
Table I Comparisons between materials of magnet
Table II Comparisons between magnetic and electric circuit
Table III Results of equivalent magnetic circuit
Table IV Comparisons between the mobile phones with digital camera now on sale
Table V Design variables and constraints
Table VI Optimal results
Table VII GA convergence generation test

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