本論文探討在微流體系統中，利用電滲流來操縱多粒子在微流道之各自運動，其回饋控制裝置包含一個即時定位粒子之視覺系統、一個驅使粒子沿預定路徑運動之控制器、以及一特殊設計之電極組。控制器根據粒子位置與預定路徑之偏差來計算電極組輸出電壓。針對特定微流道設計，可藉著改變各電極之輸出電壓來製造適當的電滲流場，其模擬乃運用FEMLAB軟體，在給定之物理常數與邊界條件下獲得。控制器需由粒子速度反求電壓，傳統上使用最小平方法來對非方矩陣做虛反置，但此法常因奇異點存在而失效，因此我們引入奇異值分解法來消除奇異點以計算近似電壓。
粒子在電滲流場之運動須考慮由布朗運動所造成之擾動，可以均值為零之隨機序列來模擬，但也可能因外在環境改變¬而產生偏移現象，須以均值非零之隨機序列來表示。當無擾動偏移時，比例(P)控制律足以產生可行的功率輸出和滿意的全程粒子運動誤差；但當擾動存在偏移時，比例積分(PI)控制律方可有效排除偏移的影響，獲得最小的末段粒子運動誤差。本文所提之最佳P或PI控制器設計皆具有良好的強健性，在系統模型參數存在誤差時仍能維持可接受的粒子運動路徑。

In the thesis, electro-osmotic actuation is employed to steer multiple particles motion independently in microchannels of a microfluidic system. The feedback control device consists of a vision system that identifies the positions of particles in real-time, a controller that drives particles along their desired trajectories, and a group of specially designed electrodes. The controller computes the output voltage of each electrode based on the difference between the particle positions and desired trajectories. For a specific microchannel design, a suitable electro-osmotic flow field can be produced by changing the voltage of each electrode, which is simulated by the FEMLAB software with given physical constants and boundary conditions. The controller demands to compute the voltages by inverting the particle velocities. For a non-square matrix, a pseudo-inverse is conventionally obtained by the least squares method. However, the method would fail because of the presence of singular points. We therefore introduce the singular value decomposition to abate singular points for the computation of the approximate voltages.
The particle motion in electro-osmotic flow should take account of the disturbance resulting from Brownian motion, which can be simulated with a zero mean random sequence. On the other hand, a shift may be encountered due to variations in the surroundings, whose simulation requires a random sequence with a non-zero mean. When there is no shift in the disturbance, the proportion (P) control law suffices to provide feasible output power and produce a satisfactory error of the particle motion for the entire path. But when the disturbance includes a shift, only the proportion-integral (PI) control law can effectively abate the influence of mean shift so as to acquire the minimum error of the particle motion for the terminal path. The proposed optimal P and PI controller designs exhibit good robustness. They can maintain acceptable paths of particle motion even though the model parameters of the system are erroneous.

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