Study On The Dynramic Control Of Steering Stability Of All-Wheel Steering Five-Axle Vehicles

In the modern life process,people have higher and higher requirements for the stability and safety of vehicle travel.Comparing with four-wheeled vehicles,multi-axle vehicles often undertake special tasks.Due to their poor working environments and special structures,the steering stability and safety of multi-axle vehicles are significantly weaker.About the multi-axle vehicle,the vehicle speed is high and the center of gravity is high during the steering process.Many traffic accidents are due to the lateral imbalance during the steering process.Therefore,a good steering control strategy is needed to improve the driving stability of multi-axle vehicles.This article is carried out from the following aspects.This paper establishes a five-axle all-wheel steering 26-DOF vehicle model in ADAMS/View,establishes a control model in MATLAB/Simulink,and combines the advantages of the two softwares to obtain more accurate test results.Modeling a five-axle oilfield drilling vehicle as a model,in which each wheel can be driven or steered independently.This structure has many degrees of freedom,and the study of steering stability is time-consuming and laborious.For the convenience of research,the model freedom is reduced.Therefore,the number of degrees is used to establish a two-degree-of-freedom dynamics model.Based on the active rear wheel steering Ackerman theory,the wheel angles can be obtained.The D value(the distance from the steering center to the first axle)is dynamically controlled in the multi-axle steering process,and the rear steering active steering is used to improve the steering stability of the vehicle.For the PID control system part,the incomplete differential control algorithm is used to reduce the high frequency oscillation of the system and improve the stability of the system.In this paper,based on the yaw angular velocity PID control strategy,the difference between the actual value of the yaw rate and the target value is used as the control input of PID to adjust the D value to do dynamical change.In order to verify the PID control strategy with yaw rate can improve the steering performance of the multi-axle vehicles.The simulation comparison experiments of steering stability are carried out in this paper,including steering wheel angle step input and pulse input test and serpentine test.The images are obtained by co-simulation and analyzed.Through a number of joint simulation experiments,it is found that the PID/D-based control strategy can improve the steering stability of the five-axle vehicles.Taking the serpentine test as an example,the simulation comparison test of FD(Fixed D value)and PID/D control strategy is carried out.The yaw rate curve of the PID/D control strategy has a small fluctuation range,and the peak value of the PID/D control strategy is reduced by 51.7%.