Singular Value Decomposition-Based Saturated Control Scheme for a Multi-DOF Wave Energy Converter

Abstract

This paper proposes a singular value decomposition-based velocity tracking control system for the multi-degree of freedom wave energy converter (WEC) to address the velocity tracking problem. Compared with our previous work presented at the conference, the detailed hydrodynamics of WEC is analyzed. In order to estimate the wave excitation force and optimal reference velocity, a linear extended state observer is employed in this control scheme. Considering that the output torque of power take-off (PTO) is limited, a novel saturated sliding mode controller is proposed to ensure that the output control torque of PTO will not exceed what the actuators can supply. With the attempt to enhance the performance of LESO, a new fuzzy logic rule is introduced into this control scheme to make the observer achieve self-tune. Based on the proposed control scheme, the power take-off system can generate appropriate control input to drive the WEC's buoy to operate at the specified speed to maximize the performance benefit of the WEC's power generation.