交換式電源於智慧型結構控制的實現與應用

Abstract

論文中利用壓電材料其電能與機械能間轉換的特性，針對其後端介面控制電路引進交換性電源供應器的設計思維，並著重結構在暫態部分的振動控制，以提昇智慧型結構振動控制之性能。當受控結構的操作頻率改變或是振動訊號大小不同時，其控制電路的設計也會有所不同。本論文中會以懸臂樑和超音波感測器(倒車雷達)，分別代表操作頻率為低頻和高頻的兩種不同結構類型進行主動振動控制。 在控制電路設計的部分，本論文首先提出半主動式振動控制，藉由在驅動倒車雷達的驅動訊號中加入部分的控制訊號，以將其殘餘的振動能量(殘響)快速的消散於電子元件中。為了使控制電路能因應不同受控結構都能有效的運作，引入以往應用於低頻振動控制的同步切換式電路，包括電感式同步切換電路、電壓式同步切換電路和速度控制切換電路，於超音波傳感器中以降低其殘響訊號。 然而同步切換式控制電路中的外加控制電壓源在倒車雷達上的應用，當結構的振動訊號較小時，其外加電壓源會造成能量回流和雜訊等穩定度的問題。為改善此缺點，本論文進而提出自適性電壓源的設計。設計架構中以一個外加電容取代原始控制電路中的電壓源，使其在結構振動時預先擷取能量並存在此電容之中，並在暫態振動控制中以此電容電壓進行控制，由於其電容電壓值會隨著振動訊號減少而降低，進而達到隨著振動位移訊號變化，控制電壓值也隨著變化的設計，其電容值可最佳化設計成振動停止時電容電壓也放電至零電壓。最終再利用自適性電壓源控制電路中的全橋電路，使控制電路同時具有驅動倒車雷達至發送超音波和殘響控制的功能。 在論文中，首先進行理論分析以了解並驗證電路設計的可行性，並透過電路模擬軟體，配合量測所得使用壓電材料的等效電路以進行實驗結果的模擬，最後再實際架設實驗，以實驗結果驗證電路設計的可行性及其控制效果。

Utilizing the characteristic of piezoelectric trasducer, which can covert electric energy and mechanical energy back and forth, this thesis focuses on the design of vibration control circuit connected with the piezoelectric transducer using the design concepts in switching power supply and aim at pursuing active vibration control in transient state. The goal is to achieve damping control in smart structures. The design of control circuit will be quite different when the operation frequency or the vibration amplitude of the structure to be controlled is different. Cantilever beams and ultrasonic sensors (used on automobile parking assistant system) will be used as the structure to be controlled in this thesis, which represent the platform of interest for low and high operation frequencies. For the design of interfacing control circuits, the semi-active damping control method was first purposed. This algorithm added an extra control signal into the original driving circuit of the parking sensor so as to damp the residual vibration energy by dissipating the unwanted energy through the electronic components efficiently while the structure is in transient states (reverberation). In order to have the active switching control circuit to work under any kinds of controlled structure and operating conditions, the synchronized switching damping control (SSD) which usually adopted in low frequency damping control is applied on ultrasonic sensor. These circuits include synchronized switch damping with an inductor (SSDI), synchronized switching damping with voltage sources (SSDV), and velocity-controlled switching piezoelectric damping (VSPD). All these methods will be examined in this thesis. Since the extra voltage source in SSD will cause stability problems due to the energy flowed back and the extra noises on the circuit, the design of an adaptive voltage v source is then purposed. In this design, an extra capacitor was added to replace the extra voltage source. The energy needed for the extra voltage source within the control circuit can be provided by the capacitor and the energy stored can be harvested from the structure vibration energy. Taking into consideration that the voltage of capacitor will vary with the the vibration signal, the optimized design for the capacitor is that the capacitor voltage will be discharged completely at the same time the vibration died out. Finally, a full-bridge circuit based adaptive control circuit that can drive the parking sensor and also perform active damping control on the residual vibration is proposed and verified in this thesis. In this thesis, theoretical analysis will first be conducted to check the viability of the circuit design. The circuit simulator is then used to simulate the experimental results before the real experiment. Finally, the completed experiment setup is then used to further verify and to benchmark the damping performance with respect to all other control methods.