Chained form and sliding mode control of farm vehicles in presence of sliding

The problem of lateral control of autonomous farm vehicles in presence of sliding is addressed in this paper. First a kinematic model is built in which sliding effects are integrated in form of additive disturbances to the ideal kinematic model. To make vehicles robust to those sliding effects, a sliding mode controller is designed by transforming the kinematic model into a perturbed chained system. With the help of natural algebraic structures of chained systems, the stability of the proposed lateral sliding mode controller is proven which guarantees convergence of lateral deviations and bounded orientation errors. Simulation and experimental results show that the proposed control law can provide high path-following accuracy even in presence of sliding.