Friction compensation based on the LuGre friction model

This article proposes two types of simple disturbance observers for friction compensation. The proposed observers are based on the LuGre friction model. One observer directly uses the LuGre model as a design base, where the LuGre model is locally linearized and observer gains are derived from the linearized model. The other one is based on a type-1 disturbance observer with the LuGre model. In the later case, the LuGre model is used in a feedforward manner. Simple simulation to evaluate positioning accuracy of observer-based state feedback control systems were conducted, and the results showed that both observers worked well for cancelling friction force in the presence of plant parameter perturbations.