Stability Analysis Of Pure Electric Buses Considering Passenger Factor

The study on the stability of pure electric buses has attracted widespread attention due to their low noise,zero emissions,and increasing importance in diversifying the transportation energy structure and maintaining national energy security.Given the large passenger capacity of buses and extreme road conditions such as steep slopes,passenger factors can affect vehicle stability,leading to safety concerns that cannot be ignored.This article focuses on a pure electric bus with four-wheel hub motor drive,introduces passenger factors,and proposes a control strategy based on vehicle stability and non-stable states to avoid instability caused by passenger factors.First,the study analyze the impact of passenger factors on vehicle stability.The study construct a vehicle dynamics model and tire model,and based on the distribution of passengers in the passenger compartment of the bus,we consider the relationship between passenger numbers,position changes,and the vehicle’s center of gravity.By changing the position of the bus’ s center of gravity,we obtain the changes in vehicle stability parameters,and use fourth-order Gaussian formula and least squares fitting to estimate the expression relationship between vehicle stability state parameters and changes in center of gravity.Secondly,the design of control and economic evaluation index estimation methods for vehicle stability.Firstly the study analyze the relationship between passenger changes and stability parameters and establish a phase plane based on the lateral deviation angle of the vehicle’s center of gravity and its rate of change to determine vehicle stability and instability states.Next,The paper study the method for controlling vehicle stability states.The paper optimize the front and rear axle torque coefficients based on the goals of maximizing motor efficiency and minimizing work done.The paper design a convolutional-gated recurrent neural network to estimate the remaining capacity of the power battery,and verify that the estimation error of both the single cell and battery pack SOC is within 3.1%.We construct a vehicle stability control model and obtain the condition of optimized and evenly distributed torque,with SOC consumption slightly reduced under the condition of optimized torque distribution.Finally,the paper study the method for controlling the unstable state of the bus.The paper adopt sliding mode control and PID control methods to monitor the vehicle’s lateral sway velocity and lateral load transfer rate for controlling the lateral sway and rollover unstable states.We obtain the lateral moment required to control the vehicle’s lateral sway and rollover,and optimize the torque allocation for each wheel hub motor based on the goal of maximizing tire utilization.The paper construct a vehicle unstable state control model and verify it under the conditions of double shifting and cross slope.The results show that the maximum adjustment of the center of gravity lateral deviation angle can reach 72% under double-shift conditions,and the maximum lateral sway velocity is 16%.Under cross slope conditions,the maximum adjustment of the center of gravity lateral deviation angle is 52%,and the maximum lateral sway velocity is 20%.