Cascaded sliding mode control for position control of a ball in a ball and plate system

Ball and Plate system is a well-known benchmark to test control strategies because of its multivariable nonlinear coupled dynamics, open loop instability and under actuation. Moreover, presence of parameter uncertainty and external disturbance makes it further challenging and interesting. This calls for a robust controller which not only stabilises the ball on the plate but also makes the ball follow a predefined path in presence of external disturbances. A Sliding Mode Controller (SMC) could be one of the possible choices. In this paper a Cascaded SMC is proposed. The effectiveness of the proposed controller is tested through simulation studies by making the ball follow a circular and a square shaped trajectories. Effect of undesirable phenomenon of chattering associated with SMC is also found within the satisfactory limit.