Longitudinal Control Of Intelligent Vehicles Considering System Delay

Intelligent vehicles are rapidly being referred to as a hot study topic and a frontier subject in the field of automotive engineering with the arrival of the intelligent era.One of these is the vehicle longitudinal control system,which is a crucial component of the intelligent vehicle auxiliary system and is extremely important to reducing traffic safety issues.This study develops a vehicle longitudinal dynamics model based on vehicle dynamics and control theory and forecasts the control algorithm for longitudinal speed planning using the model.Additionally,it analyzes the dynamic properties of the vehicle braking process and develops a braking system model with time lag links.Finally,it takes into account the disturbance brought on by external environmental changes and develops a time lag braking system model with disturbance.Based on the aforementioned two models,a time lag controller and a time lag self-anti-disturbance controller are developed in accordance with the Smith predictor and self-anti-disturbance controller principles,as well as PID control theory,to combat the effects of input time lag and disturbance on the braking system while maintaining the system’s ability to track the reference speed curve.The following topics are the primary focus of this paper’s research:(1)Based on the vehicle dynamics theory,a simulation model of the vehicle longitudinal dynamics system is constructed through study and analysis of the system.This model can faithfully depict the system motion characteristics.A time lag model of the vehicle braking system is constructed by looking at the dynamic characteristics of the actual braking process of the vehicle and the working theory of the vehicle braking system.(2)The vehicle’s longitudinal motion scenario,which includes the vehicle’s initial position,the location of the target point,and the control volume limitation,is constructed using the longitudinal dynamics model.While planning the velocity sequence as the reference value for intelligent vehicle motion control,the model prediction control algorithm is utilized to control the vehicle model from the initial position to the goal point position.(3)By using the time lag model of the braking system as the object,the Smith-PID time lag controller is created to overcome the impact of the control quantity input time lag on the braking system.It is based on the traditional PID control theory in conjunction with the Smith prediction compensator principle.Additionally,based on the time lag model,we establish the model of the time lag braking system with disturbance,design the time lag self-anti-disturbance controller based on the self-anti-disturbance control principle,and take into account the influence on the braking system caused by the disturbance due to the change in the external environment.The simulation findings demonstrate that the system can asymptotically monitor the longitudinal speed during the braking process when there is an input time lag and a disturbance present,provided that the system stability is maintained and the controller is resilient.