Saturated adaptive single-parameter backstepping design for underactuated MSVs tracking control with uncertain dynamics

Abstract

For realizing the trajectory tracking of underactuated marine surface vehicles (MSVs) in the presence of model dynamic uncertainties, actuator saturation constraints, and time-varying uncertain disturbances, a saturated adaptive single-parameter backstepping control (SPBC) scheme is developed, which possesses the properties of being model-parameter free and single-parameter adaptive. A smooth dead-zone operator (SDZO) and dynamic compensation equations are designed to deal with the propulsion system saturation constraints problem. Then, desired velocities and an auxiliary combined velocity variable are introduced to solve the potential singular problem and stabilize the subsystem of kinematics. Following that, a single-parameter adaptive law is designed in surge and yaw channels to compensate compounded uncertainties, which further alleviate computational burdens. Theoretical analysis indicates that the proposed scheme can guarantee the boundedness of all closed-loop signals. Approach efficiency is validated by simulations and experiments.