Piezoelectric Positioning Actuator Based On Bistable Structures

Precise positioning technology is a crucial intermediate way to achieve precision manufacturing and measurement, which has great potentials in aerospace, weapon systems, micro-manufacturing, integrated circuit design, surface mounting technology.Realization of Precision positioning drive technology is based on integrated design of the intelligent materials and elastic support structure. The inherent hysteresis nonlinearity of piezoelectric materials has become the bottleneck of improving the positioning accuracy and it may cause system oscillation in special circumstances with the unstable system output. Therefore, it is necessary to find new ways to eliminate the hysteresis effect from the aspects of elastic structure design. To solve these problems, this research was carried out as follows:First, proposed two kinds of actuator structure using bistable beam as elastic support for small displacement, high energy consumption and the hysteresis nonlinearity of piezoelectric materials of the influence of traditional piezoelectric actuator. Bistable jump characteristics was used to eliminate the positioning error caused by hysteresis material. Including:(a) Layout Optimization design model of piezoelectric materials on bistable actuator was established ensuring the bistable characteristics and low energy consumption. The effect of laying length and laying position on the driving energy and stroke was found by numerical simulation, (b) The design method of a wide range of bistable piezoelectric actuator was proposed. Collaborative design was used to design piezoelectric bistable beam on the displacement amplification mechanism and the connection mechanism. That is, effectively enlarge and transmit the output displacement of piezoelectric materials was realized with the reasonable design of spring. The driving bistable structure reaches a predetermined position. Numerical simulation was used to verify the feasibility of the proposed design method.Second, design method of multistage bistable precision actuator was proposed for the application requirements on the large stroke multistage precision positioning. Topology optimization design method was used to get piezoelectric material layout with the bistable bulge structure as elastic support element and low drive voltage as the object. The design of the drum package was considered as single cell structure. The axial cell and radial cell was determined by the piezoelectric materials division. Axial and radial actuation could be realized by loading on the axial and radial direction. Multistage actuator was obtained through the combination of axial and radial cell. The multi-level, multi direction combination and large displacement was achieved in both axial and radial actuating direction. The feasibility of the design method was proved by the finite element simulation analysis.Special thanks are given to National Natural Science Foundation of China (51105059, 11372063) and Enterprise, Universities and Research Project of AVIC (CXY2011DG34) which greatly supported this paper.