Research On Omni Directional Mobile AGV Control System Based On In-wheel Motor

Under supervisor of host computer,automated guided vehicle(AGV)can fulfil the tasks such as straight movement,turn and stop,etc.In traditional AGV,the power of the motor will be transmitted to the wheel by the reducer.This transmission mode has the disadvantages of complicated mechanical structure and low transmission efficiency.At the same time,the traditional AGV can only go straight or turn,can not translate,shift,pivot steering.What's more,the traditional AGV usually use PID control algorithm,which will caused some negative influences such as low response speed,unsteady running state.According to the problems of traditional AGV,an omni-directional AGV which using hub motor as power and adopting MFAC(Model-Free Adaptive Control)and fuzzy PI composite as control algorithms is designed to realize the movement of translation,shift,pivot steering and other movement modes due to the independent steering mechanism of wheel driving set.The novel AGV has the advantages of high maneuverability,high transmission efficiency and stable operation.First of all,according to the demand in industrial field,in order to simplify the structure of the vehicle body and improve the transmission efficiency,the hub-motor is selected as the driving motor and two-wheel differential steering is adopted as the steering mode.Meanwhile,the independent steering mechanism of driving wheel group is also designed to meet the industrial production requirements.With this mechanism,the omnidirectional translation of the AGV robot can be realized,which has great practical value in industrial field such as assembly production and logistics handling.The AGV mathematic model can be established based on the kinematics analysis between the differential steering and translation pattern.Secondly,based on the analysis of the mathematical model,the MFAC control algorithm and fuzzy PI control algorithm for the AGV are designed.The simulation model of two controllers is built by Simulink simulation platform.The simulation results show that the MFAC algorithm has fast response speed and strong anti-disturbance ability,the fuzzy PI algorithm has high control precision at the same time.Based on the simulation results,an MFAC-fuzzy PI composite control algorithm based on threshold switching with both advantages of the two control algorithms is proposed.Finally,an AGV using STM32 microcontroller as the main controller was designed.The MFAC-fuzzy PI composite control algorithm based on threshold switching is used to control the moving direction and speed of the robot.The response speed and robustness of the robot system are improved under the premise of ensuring the control precision.The conclusion can be drawn through comparison experiments: compared with AGV using either MFAC or fuzzy PI arithmetic,the AGV using compound control algorithm has high control precision and highly robust under the premise of ensuring fast response speed the.