Development of a hydraulic-piezoelectric-actuator for hybrid positioning control with large stroke, high loading and sub-micrometer accuracy

This paper develops a hydraulic-piezoelectric positioning system for large stroke, high precision and medium/large loading. H-control is used to solve the dual-input single-output control systems. Besides, a decoupling controller is merged for solving the structure coupling problem. The hydraulic servo cylinder serves to coarse positioning and the piezoelectric actuator positions in fine range. Because the hydraulic servo system has high response and large working force, the developed hybrid control system can implement high precision positioning for medium/high loading condition. Both the hydraulic controller and the piezoelectric controller are designed using H-control. The novel hydraulic-piezoelectric hybrid positioning servo system can achieve about 0.1 mum of accuracy for 180 mm of stroke and about 15 kg of loading mass.