Research On Obstacle Avoidance Method Of Wave Glider Formatio

Wave gliders are used as an unmanned marine observation platform,which are driven by wave energy.The float and the submerged glider are connected by an umbilical cable to form a unique double-body structure.With the demand for largescale cooperative observations of the ocean,a single device can no longer meet the complex task requirements,and the formation of multiple wave gliders has become the development trend in the future.In the process of wave gliders marching,how to realize the cooperative cooperation of wave glider formation,and how to avoid obstacles in the case of islands and other obstacles in the sea to complete the task safely,which are urgent problems to be solved.In this paper,the following research work is carried out to solve the above-mentioned problems:Firstly,the traditional artificial potential field method is studied and its principle is analyzed in detail,and the gravitational potential field model,the repulsive potential field model and combined potential field model are respectively established.Taking the wave glider as the controlled object,the force analysis is carried out,the defects of the traditional artificial potential field method are analyzed,and the simulation verification is carried out.Secondly,aiming at the shortcomings of the traditional artificial potential field method,three improvements are made.The method of calculating the intensity of the potential field instead of the method of calculating the vector force is used to control the motion of the wave glider.At the same time,the repulsion potential field function is improved,and the distance between the wave glider and the target point is introduced as the adjustment factor,which solves the problem of unreachable target.When the wave glider falls into the local minimum domain,a new gravitational input is used to break the equilibrium state under the local minimum domain and solve the local minimum domain problem.Considering the underactuation of the wave glider,the obstacle prediction model and safe driving area are introduced to help the wave glider predict the risk of collision with the obstacle,turn and avoid in advance,and improve the safety of obstacle avoidance.Thirdly,a wave glider formation strategy combining the leader-follower method and the artificial potential field method is proposed.The formation of wave gliders is realized by the leader-follower method.Aiming at the single-point failure problem of the leader-follower method,the virtual leader is used to replace the actual wave glider leader.In the aspect of formation maintenance,the idea of artificial potential field method is used and a spacing potential energy field among wave glider formations is established to control the distance between equipment,prevent collisions inside formations and realize the formation maintenance.Finally,an experimental platform is built and sea trials are carried out.The results show that the proposed wave glider formation method is effective.