| Popis: |
In this paper, the model-based adaptive control combined with a continuous robust integral of the sign of the error (RISE) feedback strategy is presented for the trajectory tracking control of an autonomous surface vessel (ASV) subject to parametric uncertainties and time-varying disturbances. The control objective is to achieve asymptotic tracking and guarantee the transient tracking performance simultaneously. An adaptive feedforward term is used to compensate for the parametric uncertainties, and the effects generated by external disturbances can be overcome by a gain of the error sign term (a part of the RISE feedback term). In the previous RISE-based feedback control, the upper bounds of disturbances and their time derivatives are often required to be known, while the requirement is relaxed, in this paper, by rendering the gain of the error sign term adaptive. It should be noted that the adaptive gain of the error sign term adjusts automatically until it is sufficient to compensate for the disturbances, which helps to reduce the control effort. Moreover, the prescribed performance control technique is introduced to provide the transient performance specification of the tracking error, which guarantees the tracking performance and improves the robustness of the control system. Based on the backstepping procedure and the Lyapunov stability analysis, asymptotic trajectory tracking with transient tracking performance is theoretically guaranteed, and all the signals are shown to be bounded. The effectiveness of the proposed control scheme is demonstrated through the numerical simulation results. |
