A new method of force estimation in piezoelectric cantilever-based microgripper

This paper presents a new approach of force estimation in a microgripper constructed by two piezoelectric cantilevers. Different from existing works on force estimation where the complicated hysteresis behavior is modeled, a more effective method is presented to estimate the hysteresis effect by resorting to a perturbation estimation technique. Based upon the identified linear model of the system plant and the hysteresis estimator, the force applied to the microgripper arm is estimated by using a force estimator. The force estimator is developed by adopting a displacement sensor only, whereas the use of force sensor is eliminated in the force detection. The proposed approach is more computational effective than the existing methods based on hysteresis models. The effectiveness of the reported force estimation technique is validated by several proof-of-concept experimental studies. It provides a sound base of force control in piezoelectric microgrippers for micro-objects handling.