Design And Development Of Rotary Type Piezoelectric Actuator Using Low Driving Voltage

Research of piezoelectric stack actuators growing vigorously in past decades and they were applied to micro-grippers,moving platform,pumps,micro motors,etc.However,actuators which works under resonant mode is unstable,frequency of its working mode changes by many factors such as temperature,preload,boundary condition,etc.When driving frequency doesn't fit with the nature frequency,output performance of actuator will be sharply decrease or even stop operating.So it means that working frequency bandwidth of resonate actuator is very narrow.In aspect of non-resonant type low driving frequency applications,piezoelectric stack usually assemble with flexure-hinged displacement amplifier.Although piezoelectric stack can provide dozens of micrometers displacement,it still not sufficient for most general engineering application.The flexure-hinged displacement amplifier has great benefits,smoothness of movement,no need of lubrication,zero backlash,and high precision.Therefore,the use of flexure-hinged mechanical displacement amplifier is appropriate approach to magnifying the output displacement of piezoelectric actuators.But such design tremendously decrease driving speed and limited stroke.We designed two type of rotary piezoelectric stack actuator by making use of flexible multi-lever linkage structure.Based on the principle of leveraging,the levers can amplify the displacement from piezoelectric stacks and transfer the vibration to the driving feet,which makes it possible to drive the actuator in a large frequency band under low driving voltage and control the output speed of the actuator precisely.Experiment results show that the linear relation between output speed and exciting frequency,the minimum operating voltage can be as low as 20 V.Dynamic model of the levers were built to analyze the relationship between structure stiffness and deformation.Finite element modeling software was used to determine the parameters of the stator structure and modify the actuator behavior.The results predicted that it is possible to achieve low voltage,long travel distance and high precision actuation with piezoelectric stack actuator.