Dual-disturbance-observer-based robust finite-time trajectory tracking control for robotic surface vehicle under measurement uncertainties

Abstract

In this paper, the finite-time trajectory tracking control of a fully actuated robotic surface vehicle (RSV) with multiple uncertainties is investigated. Particularly, besides model uncertainties, environmental disturbances, and actuator saturation, the measurement uncertainties are also taken into account. When considering the measurement uncertainties, the RSV becomes a mismatching system, which brings a great difficulty to the control design. To resolve this problem, a novel robust finite-time control approach is proposed based on a dual-disturbance-observer-based architecture. First, two finite-time disturbance observers are developed to estimate the mismatched and matched lumped disturbances in the kinematics and dynamics of the RSV, respectively. Then, the robust finite-time controller is synthesized by incorporating the two finite-time disturbance observers into the adding a power integrator technique. It is strictly proved that the robust finite-time controller can ensure the actual position and velocity tracking errors stabilize to the small neighborhoods around the origin in finite time. Benefiting from the feedforward disturbance compensation, the proposed controller is not only robust against model uncertainties and environmental disturbances, but also insensitive to measurement uncertainties. At last, the effectiveness and advantages of the proposed control approach are verified through numerical simulations on a benchmark RSV model called CyberShip Ⅱ.