Position control of a 3 DOF compliant micro-motion stage

This paper focuses on the open-loop and closed-loop position control of a three degree-of-freedom (DOF) compliant micro-motion stage with flexure hinges. This micro-motion stage has a parallel structure for better stiffness and accuracy than serial structures and is driven by three PZT stack actuators. It was discussed in the authors´ previous paper that due to the limitation of current modeling methods for compliant mechanisms the derived kinematic model is not able to accurately describe the behavior of the investigated micro-motion stage. Therefore, an experimentally determined constant Jacobian matrix is used to relate the extensions of PZTs and the end-effector movement for position control. With the use of the experimentally determined Jacobian in open-loop control, the micro-motion stage is proved able to achieve good positioning accuracy. Nevertheless, the positioning accuracy is significantly improved by incorporating end-effector closed-loop control.