Adaptive robust control of DC motors with time-varying output constraints

In this paper, an adaptive robust control with time-varying output constraints is proposed to synthesize practical high-performance motion controllers for precision DC motor systems in the presence of parametric uncertainties and uncertain nonlinearities effects. An asymmetric time-varying Barrier Lyapunov Function (BLF) is employed to ensure that the initial output can start from anywhere within the pre-set output constrained space. The global stability of the proposed controller is obtained via Lyapunov analysis, and prescribed robust transient performance and steady-state tracking accuracy are achieved even when the whole system subjects to parametric uncertainties and time-varying disturbances. Furthermore, zero steady-state output tracking error is achieved when the system only subjects to unknown parameters. The obtained comparative simulation results validate the feasibility of the proposed algorithm.