HOSIDF-based feedforward friction compensation in low-velocity motion control systems

The paper describes an application of a recently introduced methodology for modeling of a class of nonlinear systems — Higher-Order Sinusoidal Input Describing Function technique (HOSIDF) — to a motion control platform for which a precisely controlled motion at low velocity is required. One of the key challenges for these systems is to compensate for the friction, which is particularly difficult to model at low velocities. The frequency-domain HOSIDF modeling framework is used to assist in designing a feedforward compensator. Experiments with a laboratory benchmark system (gimballed camera platform) prove the technique useful.