Research On The Control Strategy Of The Braking System Of Distributed Drive Mining Electric Vehicle

With the continuous expansion of the scale of coal mine industry,mine electric vehicle has become the main transportation tool in coal mine.Environmental protection and energy saving distributed drive electric vehicle has become the focus of coal mine auxiliary transportation.When the mine electric vehicle runs in the coal mine,it needs to slow down and stop frequently,so it is of great significance to study the performance of the braking system for the mine electric vehicle.In this paper,the key problems such as braking efficiency,stability and economy in the braking process of distributed drive mining electric vehicle are studied,and the control strategy of braking system based on driving state estimation is designed.The main research contents include:(1)The structure of distributed drive braking system of mine electric vehicle is analyzed.According to the performance and power of the vehicle,the main parts of the braking system are selected,and the main parts model,tire model and vehicle dynamics model are established in Simulink software.Then the parameters are matched with the vehicle model in Carsim to verify the correctness of the established vehicle model.(2)Design the vehicle driving state estimation method.Longitudinal velocity estimation based on adaptive Kalman filter theory and real-time slope compensation is used for feedback of speed following control.A nonlinear road state recognizer was designed to identify the road adhesion coefficient in real time,and the optimal slip rate was obtained by using the recognized road adhesion coefficient.The accuracy of the driving state estimation method was verified by analyzing and comparing the observed value with the actual value output by Carsim model.(3)Based on the driving state estimation,the closed-loop feedback value of the system is obtained,and the hierarchical control strategy of the braking system is designed.Coordinate the distribution of front and rear axle braking force,design the upper braking control strategy,including the discrimination method of conventional and emergency braking mode;The control strategies for conventional and emergency braking conditions are proposed.Design the lower brake control strategy,including the optimal distribution of four-wheel braking force;Coordinate distribution of motor brake and hydraulic brake.(4)The braking system control strategy co-simulation platform was built,and the effectiveness of the braking system control strategy was verified by simulation experiments of conventional braking,emergency braking and specific braking conditions.The indexes of energy recovery efficiency and braking stability were formulated to evaluate the braking effect.The hardware-in-the-loop test platform was built to conduct real-time simulation experiments in braking conditions to verify the effectiveness and real-time performance of the proposed braking system control strategy.