Reduced Order Sliding Mode Control for High Performance Output Tracking in Non-minimum Phase Systems

This chapter discusses a method for reduced order sliding mode control design to achieve fast, overshoot-free step tracking in non-minimum phase systems. The approach involves transformation of the system into special coordinate basis form followed by a transformation that virtually stabilizes unstable zero dynamics. The tracking problem is re-framed as stabilization of the error between the system and reference state trajectories using reduced order SMC. The transient performance of the system is enhanced through the design of a nonlinear sliding surface. It initially facilitates a high-speed response and then it increases the damping factor gradually as the response approaches the reference point, thus prevents overshoot.