Design and Control Experiments of Piezoelectric Hydraulic Actuators

在本研究中，我们讨论了压电泵的数学模型及其在汽车制动系统中的应用。该压电泵由多层压电元件、膜片、泵阀、谐振管和蓄能器组成，在以往的实验中，采用直径22 mm、长55.5 mm的压电元件获得的最大泵浦功率为62W。考虑了工作液体的可压缩性、压电体的非线性特性、泵阀作用的时延等因素，建立了压电泵的详细数学模型，并将实验数据与仿真结果进行了比较，验证了模型的有效性。制动系统由压电泵作为动力源，卡钳及其活塞产生制动力，三位电磁阀改变制动位置组成。结果表明，采用直径33 mm、长度55.5 mm的压电片，可获得15 mm/s的活塞速度和20kN的活塞作用力。利用以压电泵的驱动电压为控制输入的扰动观测器，构造了活塞力的控制策略。

In this research, we discussed mathematical models of the piezoelectric pump and its application to the automoble brake system. The piezoelectric pump consists of a multilayered piezoelectric element, a diaphragm, pumping valves, resonant pipes and accumulatos, and the maximum pumpimg power of 62W was obtained in the previous experiments by using the piezoelectric element of 22mm diameter and 55.5mm length. A detailed mathematical model of the pump is derived here by considering the compressibility of the working liquid, nonlinear characteristics of piezoelectric element, the time delay of pumping valves action and so on.The validity of the model was illustrated by comparing the experimental data and the simulation results.Using the mothematical model of the piezoelectric pump, a brake system for automoble disk brake was also simulated in this research. The brake system consists of a piezoelectric pump as a power source, calipers and its piston to generate brake force, and a three position solenoid valve to change the sitsuation of brake. It was shown that 15mm/sec of piston speed and 20kN of piston force were obtained by using the piezoelectric element of 33mm diameter and 55.5mm length. The control strategy of the piston force was also constructed in this research by using the disturbance observer where control input was the driving voltage of the piezoelrctric pump.