【作者】 佟建华；

【导师】 王立鼎； 崔天宏；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2006， 博士

【摘要】 压电式传感器和执行器具有结构简单、响应速度快、高频适用性强、驱动和处理电路简单等特点,在超声检测、精密位移和定位、声学及力学量的检测等方面已经得到了广泛的应用。压电双晶梁是一种典型的力学敏感结构,是一种多功能的应用元件。作为执行器,压电双晶梁具有位移放大的特点,可以实现相对大幅度的运动空间,来完成压电叠堆型结构所无法达到的驱动效果;作为传感器,它具有柔性好、灵敏度高的特点,通过优化结构和缩小尺寸,可以测量微小的载荷。随着微电子机械系统(MEMS)技术的不断发展,采用微加工技术制造而成的微型压电悬臂越来越受到研究者的重视,并可望成为更加具有应用前景的微型驱动和传感元件。 本文在对国内外压电式微型传感器和微型执行器的研究现状和存在的问题进行了深入分析和研究的基础上,利用压电双晶梁的结构和功能特点,将其应用于压电微型电机的驱动和微力学量的测量两个方面。主要开展了以下3个方面的研究工作: 1、把压电双晶梁结构应用于压电微型电机。分析了压电双晶梁的结构特点,讨论了双压电层双晶梁和单压电层双晶梁的传感执行模型,重点分析和说明了压电双晶梁在作为执行器时所具有的对压电结构输出位移能够进行放大的特点;研究了串联型压电双晶梁,即串联弯曲臂的椭圆运动轨迹形成机理,并通过实验验证了椭圆运动轨迹的存在以及该结构的位移放大特性,获得了椭圆运动横向和纵向位移随电压幅值和频率变化的规律;首次设计了串联弯曲臂型压电微电机的结构,分析了结构特点以及驱动原理;首次制造了两种不同尺寸和驱动组的串联弯曲臂压电微电机的样机;通过实验测试了电机的性能,得到了电机的输出空载转速、输出转矩与驱动电压幅值、驱动电压频率之间的关系;研究了预紧力以及摩擦磨损对电机的输出性能的影响。实验结果表明,串联弯曲臂压电微电机的输出性能与现有的同类尺寸压电微电机比较,有了较大提高,对于直径为5mm的样机,其输出空载转速可以达到325rpm,输出转矩可以达到36.5μNm。 2、对压电双晶梁结构进行了微型化工艺研究。研究了采用溶胶-凝胶法在硅衬底上制备PZT压电薄膜材料的工艺,分析了衬底对薄膜质量的影响;分析了压电薄膜起泡和开裂的原因,并通过改进热处理条件,避免了该现象的发生。通过测试分析了PZT薄膜的结构特点、RC阻抗特性以及铁电性能参数。测试结果表明,本文所制备的PZT薄膜沿着PZT<111>方向择优生长、阻抗较高、有着优良的铁电性能;PZT薄膜的图形化工艺对其在微器件上的应用具有重要意义,因此本文研究了PZT薄膜的干法和湿法刻蚀工艺。通过改进腐蚀过程,减小了湿法腐蚀造成的侧蚀;并找到了一种有效的ICP更多还原

【Abstract】 Piezoelectric sensors and actuators with many advantages including simple structure, fast response, high frequency, and simple driving and measuring circuits, have been extensively applied to ultrasonic devices, precision positioning, detecting of acoustics and mechanic parameters, etc. Piezoelectric biomorph beams are classic sensitive structures, and they are also multifunction platforms. Piezoelectric biomorph cantilevers have shown outstanding characteristics in displacement amplification when they are used as actuators. It can realize a relatively large displacement that stack piezoelectric units can hardly achieve. When the biomorph cantilever is used as a sensor, it also has many advantages, including good flexibility, high sensitivity, etc. This cantilever can measure a micro load by optimizing the structure and scaling down the dimensions. With the development of Microelectromechanical Systems (MEMS) technologies, micro piezoelectric biomorph beams fabricated with microfabrication techniques become more and more attractive and have more possible applications to microsensors and microactuators.In this dissertation, based on the piezoelectric bimorph cantilevers, the applicatons to piezoelectric micromotors and micro force sensors were investigated, which covers the fellowing three aspects:1. The applicaton of piezoelectric bimorph structures to piezoelectric micromotors was conducted. The structures and characteristics of piezoelectric bimorph cantilevers were studied, and the models of piezoelectric microsensors and microactuators with bimorph and unimorph structures were discussed. The elliptical movement of serial piezoelectric bimorph (serial bending arm) was analyzed and verified by experiments. The track of elliptical movement was observed using oscillograph so that the characterizaton of displacement amplification was verified. The structure of serial bending arms for piezoelectric micromotors was designed, while the driving mechanism was analyzed. Two types of prototypes with different scales and different piezoelectric serial bending arms were fabricated using precise micromachining techniques. The characteristics of the micromotors were measured, and the relationship between velocity without load, torque and driving voltage amplitude, driving frequency were tested and analyzed. The influence of pre-load and abrasion on the capability of piezoelectric micromotor was analyzed. The capability of the piezoelectric micromotors was improved, compared with other piezoelectric micromotors in the same scales. The micromotors with serial bending arms 5 mm in diameter can reach its maximumrotational velocity of 325 rpm without load, and maximum torque of 36.5μNm.2. The microfabrication techniques for piezoelectric unimorph cantilevers were investigated. The approach to deposite PZT films was studied, while various thickness of PZT films were prepared by sol-gel method on the substrate of Pt/Ti/SiO2/Si. The reason of bubbles on PZT films was analyzed and overcomed using modified annealing process. The characteristics of structure, resistance, and ferroelectrics were tested and analyzed. The results revealed that the prepared PZT films are preferentially oriented along the <111> direction, and the films have high resistance and good ferroelectricity. The patterning method of PZT films with dry etching and wet etching was conducted. The undercut was decreased using a modified wet etching process. A new ICP dry etching method, with good surface quality and satisfied etching rate, was developed. The mcirofabrication process for piezoelectric silicon microcantilevers was studied, resulting in a new modified fabrication process. Three types of of silicon-based PZT microcantilevers were fabricated successfully with this modified fabrication technique. The key techniques in the cantilever fabrication rpocess were invetigated.3. The application of the Si-based PZT piezoelectric microcantilevers to micro force measurement was studied. The dynamic model of Si-based PZT piezoelectric microcantilevers was analyzed with numerical simulation, in which the dynamic characteristics of microcantilevers were obtained. The response to microforce, applied at the free end of cantilevers, and reporise to voltage, applied on the electrodes of PZT films, were imulated with CoventorWare. The modal frequencies of the microcantilevers were extracted with modal analysis. The results of numerical caculation and FEA were in a good agreement, while the coherence and errors were studied as well. The application of the Si-based PZT piezoelectric microcantilever to micro force measurement was also studied. A piezoelectric micro force sensor, with a piezoelectric bimorph microcantilever, was investigated for the first time. The working principle of the micro force sensor was discussed. A calibration method was designed for practical applications of micro force sensors to micro robots and micromanipulation systems.更多还原