Design and Test of a Compliance Controller Based on the Piezoelectric-actuated Compliant Mechanism

For grinding, polishing, and shaft-hole assembly tasks using industrial robots, flexibility demands during operation procedures of end-effectors increase rapidly. Unfortunately, current controllers are mainly focused on either the position or force, but rarely the force and position cooperation. This paper proposes a high-precision force-position cooperative compliance controller based on the compliant mechanism (CM). First, a piezoelectric-actuated CM was designed. Two force sensors and two position sensors were integrated. The statics and dynamics of the CM were analyzed and validated using the simulation. Second, the equivalent model of the piezoelectric-actuated CM was established. The force controller, position controller, and compliance controller were designed. Finally, the prototype system of the CM-based compliance controller was built. The statics and dynamics of the CM were tested. Indentation tests using three controllers were conducted. The microscope vision system and white light interferometer were employed to evaluate the performance. Prototype test results show that the CM-based compliance controller possesses a high force-position precision. The proposed CM-based compliance controller contributes to the force-position cooperative control of end-effectors of industrial robots.