Energy-Saving Nonlinear Friction Compensation Method for Direct Drive Volume Control Flange-Type Rotary Vane Steering Gear

In the research of various energy technologies, the direct-drive volume control flange-type rotary vane steering gear (DDVC-FRVSG) has become a promising component for controlling the course and posture of a vessel because of its superior energy-saving performance. However, nonlinear friction limits the ability of the DDVC-FRVSG to satisfy the efficient energy requirements of the vessel. This study proposes compensation methods to suppress nonlinear friction, such that the rudder can be efficiently controlled. Based on the principle of the DDVC-FRVSG, we establish a mathematical model and transfer function of the steering gear system along with a mathematical model of the impact of nonlinear friction on the rudder system. A friction model-based method using the integral back-stepping adaptive control strategy is proposed to suppress nonlinear friction, and both the models are studied theoretically and through simulation. Taking the no-compensation state as a benchmark, our measured results by prototype testing reveal that the method can compensate for nonlinear friction, achieving up to 73.08 % better performance on average and reducing the output power of the driving motor by 36.39 % on average. The findings of this research will contribute to the energy-saving performance and efficient energy requirement of the DDVC-FRVSG system.