Coulomb friction identification for mechatronic servo systems with limited strokes using two reference inputs

In this article, a novel approach to the Coulomb friction identification problem of mechatronic servo systems with limited strokes is presented. The proposed approach utilizes two sinusoidal position reference inputs having the same amplitude to frequency ratio, and the first order time integral of torque reference inputs over multiple time intervals of the same increment of motor position. The proposed approach is suitable for the off-line Coulomb friction identification used in the preparatory period of mechatronic servo systems with limited strokes. Coulomb friction is identified for two mechatronic servo systems in simulations and experiments, and the feasibility of the proposed approach on mechatronic servo systems with limited strokes is demonstrated.