Observer-based control strategies for compensation of dynamic friction

This paper describes and compares different observer-based control strategies for compensating the dynamic friction in controlled motion systems. The once identified system with friction requires usually an observer due to unknown disturbances and time variant friction behavior. The recently developed two-state dynamic friction model with elasto-plasticity is applied within three different types of observer, all involved in the control loop. Each of the observer-based compensation schemes as well as the friction model in feed-forwarding augments a standard linear feedback velocity control which serves for evaluation as the reference one. The performance of the realized control approaches is evaluated on an ordinary electro-mechanical actuator system with multiple coupled sources of friction without its direct measurement.