Hysteretic Modelling of Piezoelectric Actuator Attached on Flexure Hinge Mechanism

Piezoelectric actuator attached on flexure hinge is the common structure in micro manipulation system. However, it has been the fact that hysteresis is inherent in any piezoelectric actuators, especially when using voltage steering, which in turn, can degrade the performance of the system. Therefore, it should be treated carefully. In this work, a simple Dahl model is constructed to capture the hysteresis effect together with the mechanical model. For simplicity, the nature of the micro manipulator is assumed to be modelled as lumped parameters. From open-loop experimental response, a disturbance observer is constructed based on that model for estimating the hysteresis effect. Finally, some experiments are performed. Experimental result shows that the area of the hysteresis curve could be minimized significantly. However, it is still asymmetric due to the behaviour of the flexure hinge. Therefore, an integral action is added to reduce this effect. It is seen that the hysteresis could be compensated well