Research And Development Of Intensive-Storage-system AGV For E-commerce

Trajectory tracking is the key to autonomous movement of AGV and the basis to decide the performance-price ratio of AGV.In this paper,a trajectory tracking algorithm based on visual guidance and controlled by hybrid large and small deviation is proposed.Pointing at small deviation trajectory tracking,a sliding mode AGV trajectory tracking control algorithm based on combined reaching law is proposed.By establishing AGV kinematics equation,the algorithm limits the approach trajectory of the sliding mode.By using combined reaching law,large amplitude vibration resulted by variable-speed reaching law and when AGV failed to reaching the origin,high-frequency vibration resulted by exponential reaching law are eliminated.In the large deviation trajectory tracking,a sliding mode trajectory tracking control algorithm based on the Backstepping method and improved isokinetic reaching law is proposed.In isokinetic reaching law,symbolic function is replaced by continuous function.As a result,large amplitude vibration caused by rectifying large deviation is reduced effectively.At the same time,pointing at nonlinear system with multiple-input and multiple-output,this paper solved the problem of designing sliding mode control switching function effectively by using the Backstepping method.Pointing to the follow-up control problem of the AGV rotating platform for online retailers,this paper proposed an AGV rotating platform PID follow-up control algorithm with position compensator based on BP neural network.Based on the online tuning and adaptive adjustment of PID parameters,the algorithm improved dynamic performance of the PID control of rotating platform tracking angular velocity of the AGV chassis rotation with BP neural network.At the same time,by using the position compensator to avoid angle deviation accumulation in angular velocity tracking of rotating platforms,angular velocity deviation can be tracked accurately and the rotating platforms stay with constant absolute orientation.On the basis of the key technology research above,the paper has completed the design of the AGV used in the dense storage system for online retailers and developed a differential drive AGV controller based on embedded controller.Through experiment and trial operation,the feasibility and effectiveness of trajectory control algorithm and follow-up control technology has be proved.The final experiment shows that,when tracking the trajectory stablely,the angle deviation is less than 4 degrees,the distance deviation is less than 6mm,and the response time of the system is less than 2S.The follow-up platform can track the angular velocity of chassis rapidly and the accumulation of angle deviation is less than 4 degrees.Finally,the paper summarized the research work and overlooked a few topics for further study.