Adaptive friction compensation for mechanisms: A new perspective

Friction is an important aspect for control design of mechanical systems, including robotics, because it can lead to tracking errors, limit cycles, and undesired stick-slip motion. An adaptive friction compensator design is presented here as an option for control design of mechanisms with friction. Using the "simplest" friction model representation (the new perspective), consisting only of a constant value, which is assumed to be unknown, an adaptive friction compensator is developed. In numerical experiments, the system friction is modelled through a more representative function, previously used in performance evaluation of controlled systems with friction, and then using the well known LuGre friction model. Simulation results show an acceptable performance of our compensator compared with another adaptive friction compensator previously reported. The advantage of our controller is its simplicity.