Research On Key Technologies Of Double AGV Formation Cooperative Control System

With the widespread application of AGVs in the industrial field,in response to the automatic handling needs of high-end equipment large components,the high development cost of a single large heavy-duty AGV and the adaptability to different handling tasks can lead to AGV redundancy.In the face of a variety of large workpiece handling needs,adopting a dual AGV formation collaborative handling scheme can effectively reduce costs and achieve diversity of handling schemes,which has great prospects.This article focuses on the automatic handling requirements of large workpieces and mainly studies the key technologies of the dual AGV formation collaborative motion control system.In response to the need to ensure the convergence of distance deviation and angle deviation between the two vehicle centers during the collaborative movement process of the dual AGV formation,a dual layer virtual spindle combined with formation control strategy based on information consistency was adopted for the dual AGV system;Under this control strategy,research is mainly conducted from four aspects:positioning and navigation control based on LiDAR guidance,closed-loop control of differential wheel group units,synchronous motion control of single AGV multi axis group,and collaborative motion control of dual AGV formation.In addition,because CODESYS overcomes the problem of poor compatibility of hard PLC,has high real-time performance and can handle a large number of complex data and algorithms,this paper uses the controller of CODESYS platform to design the software architecture and control the motion.Firstly,in the positioning and navigation control based on LiDAR guidance,in response to the high accuracy,high resolution,and strong anti-interference ability of LiDAR mapping and positioning methods,SMET mapping software and LiDAR-LOC positioning software are used in conjunction with a single vehicle diagonal installation of LiDAR to achieve dual AGV guidance.Among them,two cars share a map,realize global positioning of dual AGVs and wireless communication based on C/S architecture,which can accurately obtain the pose information and surrounding environment information of both vehicles,as well as plan virtual paths.Through conducting LiDAR mapping and positioning experiments,the results show the effectiveness of this positioning method,with a positioning accuracy of±30mm and a repeated positioning accuracy of±10mm.The positioning method of dual vehicle shared map has a good effect.Secondly,in the closed-loop control of the lowest differential wheel group unit,the performance indicators of the rudder control are compared,and the two driving wheels of the wheel group unit are virtualized into a single spindle for motion control.The bottom drive adopts high-speed bus communication,effectively improving the stability and real-time performance of communication.Among them,the servo driver adopts CANopen communication,and the angle sensor mainly adopts Ether CAT communication;Establishing the kinematics model of the wheel set unit and adopting closed-loop control for the wheel set unit can achieve the effect of"fast,accurate and stable".The effectiveness of the wheel unit control strategy was demonstrated through ground experiments,and it was found that the fastest response speed of the wheel unit can reach 20~°/s,and the static angle positioning accuracy is±0.05~°.Thirdly,in the middle layer single AGV multi axis group synchronous motion control,according to the principle of rigid body kinematics,the kinematics model of a single AGV composed of multiple groups of differential units is established.Combined with the control idea of virtual spindle,the target control information of a single AGV virtual spindle is reasonably distributed to each group of wheel units for execution according to the motion performance of the differential unit,effectively improving the ability of multi axis group synchronous motion;In addition,according to the PLCopen axis group state machine specification,state management was carried out on multiple sets of differential wheel group units.The effectiveness of the multi axis group synchronous motion control strategy has been demonstrated through ground experiments.The single AGV multi axis group synchronous motion is stable and flexible,and there is no mutual exclusion of the axis groups during the motion process.The synchronization of the axis groups is high,and the accuracy of automatic navigation and tracking of the route is±10mm.Finally,in the cooperative motion control of the top double AGV formation,the idea of virtual spindle is mainly used to make the double AGV virtual into a spindle for motion control.According to the rigid body kinematics principle,the kinematics model of the double AGV multi group wheel unit is established;By using a positioning and navigation control scheme based on LiDAR guidance,the pose and environmental information of the two vehicles are obtained,as well as the virtual path is planned.By using a shared map between the two vehicles and combining information consistency based control strategies,the distance deviation between the virtual spindle centers of the two AGVs and the angle deviation between the two AGVs and the center line of the two vehicles are closed-loop controlled;Design hardware and software for the dual AGV formation collaborative motion control system;The need to achieve collaborative movement of dual AGV formations to jointly transport large workpieces has been demonstrated through relevant experiments,demonstrating the effectiveness of the dual AGV formation collaborative motion control strategy.