A restricted circle based position keeping strategy for the wave glider

Abstract

The wave glider is a class of wave-propelled, persistent, unmanned ocean surface vehicle. Due to the characteristics of low speed and weak maneuvering, it is challenging to control the wave glider accurately under the environmental disturbances. This paper focuses on the position keeping of the wave glider in open sea. A novel robust position keeping guidance strategy based on the restricted circle is firstly developed. Subsequently, the position keeping performance of the wave glider under different sea conditions is simulated using an eight-degree-of-freedom mathematical model. The influences of various factors on the positioning capability are investigated, including waves, current, restricted radius of circle, and control mode after entering the restricted circle. The results show that the proposed position keeping algorithm can limit the motion area of the wave glider to a certain range. Besides, under a given sea state, a smaller restricted circle ensures a better positioning accuracy, but requires more energy consumption. Waves and current both have significant impacts on the positioning accuracy and energy consumption for the wave glider position keeping.