High Performance Position Tracking With Friction Compensation For An Electro-Pneumatical Actuator

Abstract

In this paper, considering an asymmetrical Karnopp model of friction, a compensator is proposed to improve position tracking in an electro-pneumatic system. For such systems, model-based friction compensation is difficult due to the presence of actuator dynamics. The proposed compensator requires the presence of two control loops (force and position loop). For high velocity values, the compensator deals with Coulomb friction. For small velocity values, stick friction is cancelled, while for near-zero velocities, the position error is also considered in the compensator structure. Not only the compensator but also the position controller has to be optimized for high performance tracking position, and periodic reidentiffication is necessary to overcome possible changes in the system . By simulation and real-time experiments it is shown that the position tracking error is minimized.