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 decoupling property, for the estimation of the friction force. Thanks to accurate estimation, friction effects are compensated by injecting the online 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.