LAUSR

Abstract This paper first investigates the trajectory tracking problem of an underactuated underwater vehicle based on control moment gyros (CMGs) in the three-dimensional (3D) space. The controller designing process consists of three parts to form a transformed cascade nonlinear system subject to internal disturbances and input saturation. By introducing virtual control laws to simplify the position error in kinematic layer, and tracking errors can be guaranteed to converge to zero on condition that the error dynamics are stabilized. Moreover, anti-windup compensators are taken in order to deal with the problem of input saturation, and backstepping methods are exploited to construct the dynamic controller to force the error signals converge to the neighborhood of origin. Furthermore, note that attitude control torques generated by the proposed controller are actual control input for CMGs, therefore constrained steering law is utilized to achieve the global tracking control. Finally, numerical simulation studies are carried out to illustrate the effectiveness of the developed control framework.