Abstract
This paper proposes an improved controller with a friction estimator for the path tracking of a cleaning robot having a scrubbing brush, motivated by the presence of the positive influence of brush friction on robot propulsion. For the controller and the estimator, the dynamics of a cleaning robot with a scrubbing brush is represented by a model incorporating the LuGre dynamic friction model. This dynamic robot model is transformed into appropriate forms in controller and estimator design. The controller employs a sliding mode control (SMC) law improved to exploit the friction for achieving a control target. The estimator provides estimates of the state and parameters of the dynamic model in an unscented Kalman filter (UKF) framework to calculate the friction force. The performance of the proposed controller with the estimator is tested through numerical simulations. The simulation results illustrate that the proposed approach is effective for the path tracking of cleaning robots with less input torque.