Design of an indirect adaptive controller for the trajectory tracking of UVMS

For solving the trajectory tracking problem of the underwater vehicle and manipulator system (UVMS) in the presence of dynamic uncertainties and time-varying external disturbances, this paper presents an indirect adaptive control scheme which consists of three parts: an extended Kalman filter (EKF) estimation compensative system, a model-based computed torque controller (CTC), a H∞ robust compensative tracking controller. The contribution of our method is that it can overcome the disadvantages of existing control schemes, which are based on the accurate dynamic model of UVMS, known statistics unmodeled dynamics/external disturbances (e.g., constant or Gaussian), or the accurate, efficient system feedback measurement states by the sensors. According to the Lyapunov stability theorem, it is shown that the proposed indirect adaptive control scheme can guarantee its embedded H∞ robust controller tracking performance for our UVMS. Simulations show that the proposed control scheme can satisfy the design requirements of UVMS in rapid convergence, tracking accuracy, system stability and disturbance attenuation. Therefore, the method presented in this paper can provide a feasible way of controlling the nonlinear UVMS.