Research On Piezoelectric Actuator Array Drive System Used In Braille Display System

Braille book is time-consuming to product, costly and inconvenient to read and carry.Tactile display device for the blind to read the text is the development trend of technologyproducts for the blind. Piezoelectric actuator has great application prospect in the Brailletactile display field because of its notable features. Therefore, the research of piezoelectricactuator array drive system for Braille display has profound significance. The drive system iscomposed of control circuit, BOOST power supply, rapid charging/discharging circuit andstrobe circuit. In the experiment, a static pulse width modulation control strategy wasproposed to control the charging/discharging procedure, and a strobe method was used toexpand the array. The research result shows that the developed system for drivingpiezoelectric actuator array is able to achieve a quick drive to actuator, and to maintain thesteady-state voltage error within a certain range. Thence, the control strategy of actuator arraydriving has been effectively verified. The content was introduced as follows:In chapter one, the background and significance of the research was elaborated, followed byBraille knowledge, implementations of tactile display, and development of piezoelectricactuator array drive technology was discussed as well.In chapter two, the sort and respective character of piezoelectric actuator array driver wereintroduced, choosing an appropriate proposal to develop the actuator array drive system. Thework principle to achieve a quick drive for actuator array was briefly introduced, and theselection of master chip and drive power was expounded.In chapter three, the process of designing the drive power was described. On the basis ofthe principle of BOOST converter, using current-mode PWM control chip to complete theoverall circuit design.In chapter four, the response of the driving circuit was analyzed with different electricalparameters based on mathematical model. A static pulse width modulation control strategywas explained later. The simulation results of calibration system model demonstrated thefeasibility of the calibration procedure. Finally strobe control strategy was verified byanalyzing the actuator equivalent model.In chapter five, dsPIC30F2020with special function modules was chosen for master chip.The process of designing drive circuit for actuator array was described in detail, as well as the feedback circuit used for calibration. Anti-jamming measures of the driving circuit werediscussed briefly.In chapter six, hardware platform and control software was designed. Then experimentalresearch was taken over using optimized static PWM parameters. The results show that, theabove strategy of driving actuator array can achieve the desired control objectives, whichmeans the actuator has faster response speed and high steady-state accuracy.In the last chapter, conclusions of the research have been summarized, and further studywork on the Braille display system has been introduced.