| Inertial impact force is a novel kind of drive force to construct drive mechanism. At most cases, the impact force is produced by machinery rams, so control is more difficult relatively and is easy to damage the mechanism itself. Piezoelectric element has some advantages, such as high respond speed, high energetic conversion efficiency, simple structure and microminiaturization, therefore piezoelectric element becomes a type of powerful element of inertia impact drive mechanism. The drive mechanism, which uses the sharp deformation of piezoelectric element to produce inertia impact force, is called as piezoelectric inertial impact actuator. Based on the inertial impact principle, a 2-DOF inertial impact piezoelectric actuator prototype is made with the piezoelectric bimorphs as the drive mechanism and tested by this paper. The paper consists of five chapters, given as follows:Chapter 1 Introduction Because of the need of high precise location of precise engineering, piezoelectric actuator is paid more attention. Impact is a special form of vibration and has its advantages and disadvantages, To use impact as drive force is a new drive way. And it is also a new actuator research field to design precise actuator by the piezoelectric impact force. It conclude that piezoelectric material has large advantage over other materials in the precise drive field after reviewing the main types of precise drive, piezoelectric actuator's main forms, characteristics and representative usage and the driving materials. At the same time, the problem that exits in the piezoelectric precise field at broad and home is put forward. Then a review about the research emphasis and research results of piezoelectric impact drive at broad and home is given. The main research content of the paper is list at last.Chapter 2 Piezoelectric performance analysis and the inertial impact drive principle The piezoelectric drive fundamental principles are piezoelectric effect and converse piezoelectric effect. The factors which influence performance include dielectric constant (,elastic constant s ,piezoelectric constant d ,electromechanically coupled coefficients K,mechanical quality factorQm,etc. With reference to the selected piezoelectric material, the dielectric constant matrix,elastic constant matrix,piezoelectric constant matrix of PZT is put out specially, which will be used in the FEM analysis in the chapter 3. Piezoelectric is a kind of elastic solids, it has four piezoelectric equations with different independent variable at various boundary conditions. Piezoelectric bimorph adopt the LE mode of piezoelectric oscillator and is a piezoelectric component with large deformation output, easy-to-control, higher response rapid which suits for the inertial impact precise drive. According to the previous cantilever beam piezoelectric bimorph equations, the trend is concluded that the dimension of piezoelectric wafer and base influence the beam's free end displacement, the stiffness and frequency of the cantilever beam, which will be taken as the academic gist for designing the piezoelectric bimorph. Inertial impact drive principle is the academic base of 2-DOF piezoelectric inertial impact actuator, based on it, the way to utilize the piezoelectric bimorph to drive mechanism linear motion and rotation is given.Chapter 3 Inertial impact actuator structure design and analysis Based on comparing the planar multi-freedom inertial impact actuators structures designed by our lab, the paper provides a new design-axis vs. hole contact, by which the motion along axis and rotation around the center will be fulfilled and which is convenient for motion orientation and output of drive. By examination and FEM two means, the static and dynamic analysis of the piezoelectric bimorph oscillator is carried out in this paper, and the relation between the dimension of bimorph and the performance of it is got, which proves the conclusion in the chapter 2. In order to improve the test rapid and accuracy, an aut...
|
PDF Full Text Request