Load positioning for subsea installation via approximation based adaptive control

Abstract

In this paper, positioning control is investigated for the installation of subsea hardware with thrusters attached under time-varying ocean current. Adaptive neural approximation techniques are employed in the design of the control law and the stability is demonstrated by means of a backstepping and Lyapunov synthesis approach. Semiglobal uniform boundedness of the closed loop signals is guaranteed. The proposed control law is able to generate the control action required for accurate positioning without exact information on the hydrodynamic coefficients of the structure and current measurements. The performance of the proposed controller is evaluated via numerical simulations. From comparative simulations, the proposed technique is found to be effective, robust and produced an improved tracking performance. © 2007 IEEE.