H2-control with acceleration feedback for a micro positioning system

The precision and micro assembly requires special tools in order to fulfil the high demands in accuracy and control of the assembly process. Our new precise gripper tool with 2 DOF, the micro positioning system (MPS), enables micro assembly with standard industrial robots by compensating for vibrations and inaccuracies of the handling device. The new developed control system combines data of three diverse sensors to perform the corrective movement. The designed control system of the MPS consists of two closed-loop and one open-loop regulator. A classical control design with pole-zero cancellation is used to linearize the hysteresis of the piezo actuator. An H₂-regulator using only acceleration feedback is the main part of the control system and generates a control signal proportional to the position for the actuator´s corrective movement. The third regulator handles the reference input. The realized control system reduces vibrations to less than 30%, the position accuracy without disturbances is better than 2 microns according to experimental results