Friction compensation in nonlinear dynamical systems using fault-tolerant control methods

This paper describes the application of differential geometry and nonlinear systems analysis to the estimation of friction effects in a class of mechanical systems. The proposed methodology relies on adaptive filters, designed with a nonlinear geometric approach to obtain the disturbance de-coupling property, for the estimation of the friction force. Thanks to accurate estimation, friction effects are compensated by injecting the on-line estimate of friction force to the control action calculated by a standard linear state feedback. The inverted pendulum on a cart is considered as an application example and the proposed approach is compared with a commonly used friction compensation strategy, based on an explicit model of the friction force.