Research On Traction And Braking Control System Of Small-Scale Skytrain Driven By The In-Wheel Motor

With the continuous progress of urbanization in China,the urban size has been also expanding and the proportion of urban population has been rising,resulting in traffic congestion,single means of transport,traffic impact on the environment and other transportation problems are becoming increasingly prominent.According to relevant research,vigorously developing public transportation is an effective way to solve urban traffic congestion.The sky train(also known as suspended monorail vehicle)of monorail system has the advantages of comfort,punctuality,low cost,short construction period and land saving.Therefore,in order to solve the transportation problem,the sky train can be used as a supplement to the urban public transportation.This study,taking the traction and braking control system of small-scale sky train driven by the hub motor as the research object.Firstly,through the research status of sky train,hub motor control and braking technology at home and abroad,the composition of traction and braking systems for small-scale sky train is determined,and the calculation and selection of power supply devices,traction motors,braking systems and control units are completed.namely: the traction motor is a hub motor with rated power of 1.5kw and rated voltage of 72 V.The power supply device is 600 V DC power supply from the collector shoe.The backup power supply is a lithium battery with a total voltage of 72 V and a capacity of 20 Ah.The control unit is the STM32F407ZGT6 of the Cortex-M4 core,and the traction mode is independent driving of the four hub motor.Compared with the control strategy of single motor,the FOC vector control is selected to control the hub motor,and the FOC vector control process is also elaborated.At the same time,the deviation coupling is selected to realize the synchronous control of the four motors.However,in order to better realize the synchronization of four motors,this paper combines fuzzy PI control with deviation coupling and there by fuzzy control is designed.Secondly,the steering control of small-scale sky train is analyzed and calculated,then the analysis and calculation of the steering control of the small-scale sky train;finally,the braking function of the small-scale sky train-common braking,fast braking,emergency braking,parking brake and anti-skid protection,and braking force Calculation and braking force distribution.Secondly,In order to achieve traction braking control,the main program of traction braking control is designed first.Then the working condition processing,AD/DA conversion,CAN bus,interruption module,fuzzy PI control module,fault monitoring and treatment under traction mode are elaborated in detail.At the same time,the working condition processing,deceleration calculation,braking power distribution and electric cylinder driving under braking mode are introduced.Finally,The single hub motor is controlled by bench test,and the PID parameters,stability and error of the control results are analyzed.In order to verify the feasibility of the traction and braking control strategy for small-scale sky train,this paper builds a single-motor traction control strategy,four-motor traction control strategy and steering control simulation model through MATLAB/Simulink,and the joint simulation of braking control strategy with AMEsim simulation software is used to verify the feasibility of traction control strategy and braking control strategy for small-scale sky train.