Research On Structure Design And Path Planning Algorithm Of AGV

With the rapid development of the Internet of Things and robotics,the automation level of workshop logistics systems is increasing.Automated Guided Vehicles(AGVs)have become the core equipment of modern workshop logistics systems with their high degree of intelligence,flexibility,safety and other characteristics,which can significantly improve logistics efficiency.Currently,due to the special environment in food workshops,many companies still use low-efficiency manual transportation methods.To this end,this project will design a differential drive AGV based on ribbon optical navigation according to the actual needs of the food factory,and conduct an in-depth research on key technologies such as mechanical structure stability,trajectory tracking controller,path planning and scheduling algorithms.The specific research of this paper is as follows.Firstly,the mechanical structure,control system and scheduling system are designed according to the design needs and technical indexes,and the chassis layout,vibration damping form,navigation and positioning mode and scheduling system framework of the AGV are determined after comparative analysis.Next,the structural stability of the AGV is studied.Using the finite element analysis software to conduct static and modal analysis on the frame of the AGV structure with more forces to ensure that the structural strength of the vehicle body meets the requirements and prevent resonance.The force analysis of the articulated swing damping structure was conducted to figure out the range of damping spring stiffness.The motion simulation was conducted in ADAMS dynamics analysis software,and the influence of different spring stiffness on driving stability was analyzed under two cases of full load and no load.An appropriate spring stiffness was finally selected,and the simulated results verified the rationality of the structure and model.Then,the trajectory tracking control strategy of the AGV is studied,and then design the variable universe fuzzy PID controller.By analyzing the motion state of the AGV,the kinematic model of the differential drive AGV is established and the equations of motion are derived.In order to further improve the control accuracy,based on the fuzzy PID theory,the variable universe idea is introduced to multiply the basic universe of the input and output variables with the scaling factor to realize the dynamic adjustment of the universe,which indirectly increases the density of the control rules when the error is small to improve the accuracy of the controller.By conducting simulation comparison experiments,it has been determined that the designed controller can effectively improve the speed and stability of AGV trajectory correction.Then,the single-source path planning algorithm and the time window scheduling algorithm are investigated.The search efficiency is improved by improving the heuristic function on the traditional A* algorithm;the number of corners is reduced through considering the cost of turns.To solve the multi-AGV path conflict problem,the congestion function is first added to the A* algorithm to consider the node congestion in order to avoid the congested section in advance when planning the path;then the path distance compensation is added to the time window algorithm,the temporal conflict is regarded as the extension of the path,which transforms the two-dimensional solution of the conflict-free path problem in time and space into a single-dimensional solution of the shortest path problem,and seeks the global optimal solution by considering the cost of both waiting and changing path strategies.Finally,the ribbon optical navigation AGV prototype is built and the scheduling system is designed for the trajectory tracking,single-source path planning and multi-AGV path planning experiments.The experimental performance indicates that the AGV and controller designed in this paper can realize the tracking function of ribbon path,and the scheduling system can plan the single-source shortest path and multi-AGV conflict-free path.