【作者】 张忠华；

【导师】 孙宝元；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2009， 博士

【摘要】 基于压电效应的传感器与执行器以其优越的性能在国民经济和国防工业中发挥着独特作用,现代精密测试与驱动技术的发展迫切需要深化与扩展压电理论,对多次压电效应的理论与应用研究势在必行。本文在国家自然科学基金（50675026）的资助下,运用压电学、晶体物理学、电介质物理学、各向异性弹性力学等交叉学科的理论,对压电晶体多次压电效应进行了深入系统地研究,研制出基于多次压电效应的微执行器和自感知执行器。本文具体工作如下:基于经典压电理论研究了压电晶体的纵向三次耦合效应,提出压电晶体三次正、逆压电效应的实验研究方法。从四类压电方程出发,推导出压电体分别在外应力和外电场作用下的多次压电效应的通用数学模型。通过与改变PZT-5叠堆边界条件等效的实验方法得到了纵向三次耦合效应,实验表明三次正、逆压电效应产生的结果与压电叠堆所施外场具有良好的线性关系,实验结果不仅验证了多次压电效应理论的正确性,而且证明了所提出的实验方法的科学性和可行性。同时,采用两片由压电系数d₁₁转换的xy切型石英晶片制成压电石英晶组,研究了工程实际中广泛应用的压电石英三次压电效应,通过与压电石英晶组并联远大于其等效电容量的电容,消除了压电石英中的多次压电效应,从而量化压电石英晶体的纵向三次压电效应,并得到了多次压电效应对石英传感器静态灵敏度的影响结果,实验表明压电传感器的静态灵敏度提高了1.75%。分析了多次压电效应对压电石英力传感器刚度、固有频率和机电耦合系数的影响。研制开发出基于压电陶瓷叠堆多次压电效应的微执行器。研究了基于多次压电效应微执行器的原理,并验证了其可行性。通过选择微执行器的核心元件,确定其结构形式和预紧方式,从而建立了微执行器的力学模型,设计了微执行器的执行板和壳体,得到各部件的尺寸参数,并通过有限元分析进一步验证了微执行器的各部件参数选择的合理性,最后研制出基于多次压电效应的微执行器。对微执行器进行了性能检定,静态标定结果表明微执行器的外载荷与其输出电压、弹性位移以及二次逆压电位移均具有良好的线性关系。在动态标定中得到微执行器的固有频率为4.433KHz。该微执行器不仅能够实现弹性位移和二次逆压电位移的两次定位,而且可通过微执行器的一次正压电效应进行外载荷的校验。基于多次压电效应理论进行了压电执行器位移自感知的研究,提出基于多次压电效应自感知执行器的解耦方法。通过引入参考电容,采取电流积分与差分比例运算电路相结合的方式进行PZT-5叠堆执行器的位移自感知实验,结果表明压电执行器本身产生的多次正压电效应可以反映其输出位移信息,同时证明了解耦方法的正确性,从而得到一种较传统电桥电路解耦更易于在工程实际应用的方法。以基于压电陶瓷多次压电效应的微执行器为对象,进行了其位移自感知的实验研究,实验结果进一步表明基于多次压电效应的自感知方法能够很好地获取出该微执行器的位移输出信号。更多还原

【Abstract】 Nowadays, piezoelectric sensors and actuators which have superior performance play a unique role in the national economy and defense industry. The development of modern precision testing and driving technology urgently needs to deepen and extend the piezoelectric theory. Therefore, it’s imperative to study the theory and application of multiple piezoelectric effects. This paper, supported by the National Science Foundation under Grant No. 50675026, studies on multiple piezoelectric effects through using the knowledge of different disciplines such as piezoelectricity, physics of dielectrics, physics of crystals, and theory of anisotropic elasticity. And then the microactuator and self-sensing actuator based on multiple piezoelectric effects are developed. The specific work in this paper is as follows.Firstly, according to classical piezoelectric theory, tertiary coupling effect under longitudinal mode of piezoelectric crystal is investigated and the validation methods of tertiary piezoelectric effects are proposed. On the basis of four kinds of piezoelectric equations, the general mathematic models of multiple piezoelectric effects are deduced under applied force and electric field. The experimental results of this tertiary coupling effect of PZT-5 are obtained by the methods that are equivalent to changing boundary conditions. Experimental data shows that the output of tertiary direct and converse piezoelectric effect is linear with the applied force and voltage, respectively. As a result, theoretical analysis is justified by experimental results, just as experimental methods are proved scientific and feasible. Moreover, through a piezoelectric group composed of two xy cutting-type quartz wafers transformed by du, the tertiary piezoelectric effect of piezoelectric quartz which is applied on practical engineering widely is studied. The result of the tertiary piezoelectric effect of piezoelectric quartz is quantified by using a capacitor parallel with the piezoelectric quartz group to eliminate multiple piezoelectric effects. At the same time, the influence of multiple piezoelectric effects on static sensitivity of piezoelectric quartz sensors is obtained. Experimental results show that sensor’s static sensitivity is increased by 1.75%. The influence of multiple piezoelectric effects on the stiffness, natural frequency and electromechanical coupling factor of piezoelectric quartz force sensors is analyzed.Secondly, the microactuator based on multiple piezoelectric effects of PZT stack is developed. The principle of microactuator based on these effects is demonstrated. Its theoretical feasibility is validated through the experiment. After choosing the core element, structural form and pretightening mode of the microactuator, a simplified mechanical model of the microactuator is established. According to the model, the actuation plate and shell of microactuator is analyzed and designed. In this way, the size parameters of each component are obtained. The functionality of component parameters’ selection is further validated through FEM analysis. Finally, the microactuator based on multiple piezoelectric effects is developed successfully. The results of static calibration show that there is a strong linear relationship between the output voltage, elastic displacement and output displacement of the secondary converse effect of the microactuator and external loading. In this dynamic calibration, natural frequency of the microactuator is 4.433KHz. The microactuator not only can realize dual-stage position of elastic displacement and secondary converse displacement, but also can check the external loading through the primary direct piezoelectric effect of the microactuator.Thirdly, the research of the piezoelectric self-sensing actuator is performed on the basis of multiple piezoelectric effects and the decoupling method of self-sensing actuator based on multiple piezoelectric effects is proposed. Through a referenced capacitor combined with current integration and a differential proportional operational circuit, this self-sensing experiment of displacement of a PZT-5 actuator is performed. The experimental results indicate that multiple direct piezoelectric effects generated by the piezoelectric actuator itself may totally reflect the information of the output displacement of actuator. Meanwhile, it proves that the decoupling method is correct. Consequently, a decoupling method that is easier for practical engineering application than electric bridge circuit is obtained. Through adopting the microactuator based on multiple piezoelectric effects of ceramics, the experimental research of self-sensing of displacement of the microactuator is performed. Experimental results further show that the self-sensing method based on multiple piezoelectric effects may well acquire the signal of the output displacement of the microactuator.更多还原