Research On Braking Stability Control Of Distributed Driven Electric Vehicle Based On Braking Intention

The distributed drive electric vehicle has extraordinary dynamics controllability due to its special vehicle structure which could control the drive or brake torque of each wheel individually,thus it has the special meaning for improving vehicle handling stability.The identification of drive intention has a positive impact on improving vehicle running safety.At present,the researcher's main study point mainly focused on the identification accuracy of braking intention,there are few studies on vehicle dynamic control combined with braking intention,therefore,this paper makes a detailed study on the braking stability of distributed drive electric vehicle on straight and curve based on driver's braking intention identification.In this paper,the research vehicle is firstly determined to be a distributed driven electric vehicle driven independently by four wheel hub motors and equipped with electro-mechanical brake system(EMB),a seven DOF vehicle model was used to analyse the problem,and the vehicle driven motor model,EMB model,wheel vertical load estimation model and road identification model were constructed respectively.In the mean time,the Carsim vehicle model was also constructed.Then the type of braking intention,the intention identification feature and the input/output variables were determined individually,and the identification structure of intention recognizer was designed using the fuzzy logic theory.The straight braking sliding mode controller of distributed drive electric vehicle was designed based on wheel slip rate in this paper,two different straight braking scenarios was chosen to validate the effectiveness of straight braking sliding mode controller,and then the co-simulation was conducted based on Simulink and Carsim,the co-simulation results show that,not only could this controller guarantee the straight braking efficiency,it also could ensure the straight braking stability and comfort.The curve braking stability coordinated strategy of distributed drive electric vehicle was put forward in this paper,which is controlled by the vehicle yaw velocity and side slip angle.The top controller determined by reference model and braking intention recognizer was designed based on using layered control structure,in order to design the bottom controller,this paper use active set method to solve quadratic program problem using the tire utilization rate as target.Carsim and Simulink were used to simulate the changing braking intention of distributed drive electric vehicle on slip-? road,the co-simulation results show that,not only could this controller meet the longitudinal brake needs,at the same time,it also could maximize the vehicle curve braking stability.