Adaptive force/position control with unknown parameters estimation for a piezo-driven micromanipulator

Microgripper driven by piezo-actuator plays an important role in various fields because of its highly accuracy. Nowadays, precise position control has been achieved through different approaches. However, precision position and force control is always a critical issue for automated microassembly systems to handle micro-objects delicately. The existing difficulties come from external disturbances, such as vibration, hysteresis, etc. This paper presents an approach to regulate the position and force at the same time, dedicated to tackling the problems mentioned above. This approach is based on the sliding mode control. The adaptive control law is designed to minimize the influence of the unknown and unmodeled items, which is also guaranteed the stability by Lyapunov theorem. The validation of the approach is verified by Matlab simulation results.