A Pressure-Displacement Control for an Active-Passive Hybrid Compensation System

Deep-sea towing system is widely used in a variety of fields, such as seabed resource exploration, and high-power soar drag. During offshore installations or towing in harsh sea conditions, the involved towing system must satisfy rigorous requirements in terms of safety and efficiency, and towed body produce huge heave movement with vessel irregular movement due to wave action. So, there are a lot of heave compensation systems proposed to buffer and compensate towed body's heave movement, but for high order and nonlinear systems, some simplification is usually used to avoid this phenomenon. In this paper, an adaptive back-stepping sliding mode controller, with friction and nonlinear structure taken into consideration. is designed to keep a relative displacement for the underwater load, and the MATLAB simulation results prove the effectiveness of the proposed controller. The mathematic model and the nonlinear control mothed in this paper can be a guide to real systems.