Research On Autonomous Collision Avoidance Algorithm For Unmanned Surface Vehicle Considering Dynamic Constraints

In recent years,autonomous navigation technology has been widely used in many fields,and the development of unmanned vehicles,unmanned aerial vehicles,and unmanned surface vehicles is in full swing.Autonomous surface vehicle has become the main development trend of maritime ships with their unique advantages and have received the key attention and R&D investment of various powerful countries on the sea.As an important part of autonomous ships,the automatic collision avoidance decision module is also a hot issue in USV research.This paper mainly studies the following aspects of the dynamic collision avoidance algorithm of USV.(1)For the discussion on the development status of USV at home and abroad,various algorithms are analyzed and compared from the two perspectives of reactive collision avoidance and path planning collision avoidance.It focuses on the characteristics of related algorithms for Autonomous surface vehicle to avoid collisions.And choose the classic Velocity Obstacle algorithm as the algorithm core of this article to study the collision avoidance problem.(2)The theoretical basis of USV’s realization of dynamic collision avoidance is analyzed in detail,which mainly includes the perception modeling of the surrounding environment of the USV and the calculation of related parameters of the USV motion model,and multiple collision-related parameters are integrated to calculate the collision risk of ships.Combining the ship’s collision avoidance experience to determine the weight of a parameter,the ambiguous ship hazard degree is converted into a quantifiable standard.At the same time,in order to comply with the existing maritime ship collision avoidance rules,the COLREGs rule is integrated into the collision avoidance decision-making process.(3)Based on the introduction of the traditional speed obstacle method theory,the collision avoidance speed selection based on the speed obstacle method is optimized by adding constraints on heading stability and route retention,and the situation is encountered in multiple ships.The optimal collision avoidance decision is achieved by dividing the core collision zone and the generalized collision zone.(4)For special nonlinear navigation obstacle ships,it is proposed to add virtual obstacles to avoid collisions,and to increase the constraints of coasts and islands in the USV collision avoidance speed space.Through the establishment of a multi-level optimization method based on the speed obstacle method,the situation of encountering,crossing,and overtaking two ships is simulated,and at the same time,the collision avoidance problem of the non-linear motion of the obstacle ship is simulated in a variety of situations.The simulation results show that the multi-level optimized collision avoidance decision-making system based on the velocity obstacle algorithm has good performance.It can not only make obstacle avoidance decisions that comply with COLRGEs,but also complete obstacle avoidance to ensure the safety of the ship when the obstacle does not comply with the rules.