Research On Drive/Braking Stability Integrated Control Of 4WD Vehicle Based On VeriStand Hardware-in-the-Loop Platform

With the development of automobile control technology,ESP control technology has been widely used in all types of four-wheel-drive vehicles.When the vehicle is running,it will encounter driving instability conditions,such as over-steering or under-steering when the vehicle is steering.The ESP system will start to work after detecting such situations.The braking force is distributed to each wheel according to the value calculated by the control strategy to generate yaw moment to correct the vehicle steering and driving track.In order to ensure the safety of driving,the ESP system frequently works,braking has a great impact on the dynamic performance of the car,and the braking effect will reduce the comfort of passengers.Different torques are distributed to each wheel by active power to generate yaw moment to maintain the stability of the vehicle.The yaw moment generated by different driving forces on each wheel is not enough to maintain the stability to meet all driving conditions.After a series of simulation tests,it is found that the yaw moment generated by the active power distribution control can also improve the steering stability and ensure the dynamic performance of a part of the vehicle when the driving condition is in a certain region.Therefore,an integrated control method is proposed,which uses the control strategy designed according to the driving condition region obtained from the simulation,and determines the available control mode to maintain the vehicle driving stability under different driving conditions.Effect in this paper by simulation experiments two control ways for vehicle stability control effects of three factors,the car speed,front wheel steering Angle and the tire-road friction coefficient,and draw out the alternative can be controlled by the active power distribution of braking force distribution control area boundary,thus build the drive/brake control strategy of the integrated control system of the upper.In the integrated control system,the lower control is composed of two subsystems,active power distribution control system and braking force distribution control system.The lower control system is directed by the upper control strategy.The joint hardware simulation based on Veristand,Simulink and LabVIEW is used to connect the braking system and power distribution system in the vehicle,such as the electrically controlled central differential and the inter-wheel motor type electronic limited slip differential,into the simulation system.The Veristand based 4WD vehicle drive/brake stability integrated control hardware in the loop platform.According to the results of hardware in-loop test,it can be verified that the drive/brake integrated control system designed in this paper meets the requirements.