A SLIDING MODE-BASED MODEL-FREE CONTROL FOR WHEELED MOBILE ROBOTS

Reference tracking and point stabilisation control of mobile robots require a significant effort for reliable and effective operations. A model-free robust controller based on a sliding mode-based tracking differentiator and a continuous sliding-mode control approach is proposed for controlling the wheeled mobile robots with differential drives. For robust point stabilisation and trajectory tracking of the nonholonomic mobile robots, a cascade control structure composed of an outer kinematics control loop and an inner speed control loop is designed. The sliding mode tracking differentiator is designed to smooth the reference signals to eliminate velocity jumps and to calculate the derivatives for designing the outer kinematics controller. Using the particle swarm optimisation-based method, control parameters are tuned for the best possible control performances. Control implementation results are provided to show the non-overshoot response and zero steady-state performance of the control system.