Research On Online Formation And Obstacle Avoidance Algorithm Of Logistics Robots

With the rapid development of logistics industry,multi-robot formation technology has become one of the effective means to reduce logistics transportation costs,improve the efficiency and safety of warehousing logistics,and multi-robot system is also widely used in warehousing logistics transportation.Based on the unstructured environment of warehousing and logistics scene,multiple robots are required to form and maintain formation structure online while frequently avoiding obstacles and minimizing energy consumption and time waste.Therefore,how to design efficient online formation and obstacle avoidance algorithm of logistics robots has become a research hotspot in the field of logistics transportation.Based on the above background,this thesis carries out research on online formation and obstacle avoidance algorithm of logistics robots.The main work and contributions are summarized as follows:1.Optimization of formation consistency control based on MPC algorithm.Aiming at the problem of online consistency control in robot formation,this thesis proposes a method to improve the traditional leader-follower formation control model,which increases the convergence speed of formation,and establishes formation database to realize better formation control.On the basis of above,considering the high real-time requirement of online formation,the model predictive control algorithm(MPC)was used to optimize the formation control,and a good effect of online formation consistent control was obtained.2.The dynamic formation transformation strategy and the whole formation obstacle avoidance planning algorithm are proposed.Based on the improvement of obstacle modeling method,a dynamic formation transformation strategy was proposed.According to the transformation performance evaluation function,the formation structure which is most suitable for the current environment was obtained.Three forms of formation transformation,namely isomorphism,isomerism and preservation,were used to pass obstacles more efficiently.At the same time,in order to solve the obstacle avoidance problem in warehousing and logistics environment,a high real-time trajectory planning algorithm based on cubic B-spline curve was proposed for the overall formation structure.A multi-objective trajectory optimization model was established,which included curve smoothness,obstacle avoidance path length,total bypass path length,obstacle avoidance energy consumption of formation and deformation degree of formation transformation.Thus,an obstacle avoidance trajectory with both obstacle avoidance efficiency and energy consumption is obtained.3.The obstacle avoidance algorithm of individual formation is optimized based on the double closed-loop control strategy.In the face of small obstacles in warehouse logistics environment,a double closedloop control obstacle avoidance algorithm combining model predictive control algorithm and virtual impedance method was proposed.In order to solve the obstacle avoidance problem caused by the same attractive and repulsive forces in traditional virtual impedance method,auxiliary adjustment force was introduced.For dynamic obstacle avoidance problem,dynamic obstacle avoidance factor is added,so that the obstacle avoidance controller can also have better obstacle avoidance performance when facing dynamic obstacles.This algorithm not only ensures that the formation does not collide with the dynamic and static obstacles in the environment,but also solves the problem of formation consistency control after obstacle avoidance.4.Logistics and transportation application experiments based on simulation and simulation scenarios.Aiming at the transportation problem of logistics robot formation in warehouse logistics environment,the application experiment is carried out.MATLAB simulation and multi-robot simulation application experiment scene are used to carry out the experiment respectively from the perspective of simulation and real object.The results show that compared with the traditional multi-robot formation and obstacle avoidance algorithm,the optimized algorithm in this thesis can complete the warehousing and logistics transportation task more efficiently,which verifies the reliability and efficiency of the proposed algorithm.