Practical trajectory tracking of random Lagrange systems

The problem of trajectory tracking is considered in this paper for Lagrange systems disturbed by second moment processes. For random differential equations, the concept of noise-to-state practical stability and its criterion are proposed. A state-feedback tracking control is designed by using vectorial backstepping method, which covers Slotine–Li controller and “PD+” controller as special cases. As natural extension, adaptive control is further researched, and a practical equivalence principle is presented. For the above two cases, results of global noise-to-state stability of closed-loop systems are obtained, and practical trajectory tracking can be achieved under a practical parameters-tuning principle. Simulations are conducted for a nonlinear benchmark system to illustrate the effectiveness and advantages of the proposed new control strategies.