Research And Design Of Automatic Driving And Accurate Positioning System For Monorail Tractor

With the rapid development of China’s rail transit,the supporting equipment of straddle monorail also needs to be upgraded.As an important equipment for the wheel maintenance of straddle type monorail trains,the existing vehicle for towing has the problems of low efficiency and lack of accuracy.In order to realize the traction automation and improve the efficiency of traction operation,the vehicle for towing automatic driving system is designed.This paper first introduces the monorail train and the vehicle for towing,analyzes the working process of the tractor,and then designs the automatic traction system and the automatic traction process.Based on the design of the positioning method of the vehicle for towing,the parking link and the coupler link in the vehicle for towing are analyzed,and the formulas of the vehicle for towing parking and coupler deceleration are deduced.Design and calculate the hydraulic system of vehicle for towing.Analyze the load resistance in each working condition of the vehicle for towing,and calculate the traction required by the tractor as the basis of the speed control system.Based on the analysis of the speed control strategy of the vehicle for towing,a speed control method combining precise speed control and power control is proposed.The power matching system of the vehicle for towing is designed,and the constant power speed control system of the vehicle for towing is designed according to the power matching principle.The fuzzy control algorithm is used to realize the power load matching.The mathematical model of the engine and variable pump control device is built in MATLAB,and the constant power system is simulated with the transfer function of the variable pump control system.The simulation results show that the constant power system can be realized The engine power matches the load and has good dynamic performance.The paper designs the precise speed control system,models the mathematics of the hydraulic system,gives the transfer function of the system,analyzes the dynamic performance and the steady performance of the system based on the transfer function,designs the conventional PID correction and the fuzzy PID control correction,and carries on the contrast simulation to the system in Matlab,the simulation result shows that both the conventional PID and the fuzzy PID can improve the dynamic performance of the system,and the fuzzy PID control effect is better.Finally,the software system of the vehicle for towing is studied.OPC technology is used to communicate between the client of the upper computer and the control of the vehicle for towing owner,and VB programming is used to realize the communication between the upper computer and the main control PLC.The wireless communication module is used to communicate between the main control PLC and the on-board PLC,and the Modbus protocol is used for the communication.The analog quantity and speed signal acquisition method and the step motor control method used in the system are introduced.