Platoon Control Of Connected Vehicles Based On Distributed Sliding Mode Control

In recent years,the platoon control of interconnected vehicle systems has attracted extensive attention of scholars.Platoon control has become one of the important branches of intelligent transportation system.The platoon control of interconnected vehicle systems can effectively improve the safety,alleviate traffic congestion and reduce energy consumption.However,uncertain factors such as environment variability,communication fault and unknown parameters in interconnected vehicle systems often affect the stability of the platoon,and even lead to traffic accidents.At present,the research on the interconnected vehicle systems mainly focuses on how to realize the string stability of the platoon systems.The control strategies considering the external disturbance,chattering suppression and input saturation of the platoon systems are not well explored.This paper mainly studies the platoon control of interconnected vehicle systems with uncertainty.The main research contents are as follows:For the platoon systems with external disturbance,considering the decline of traffic density caused by large initial spacing error,a distributed adaptive sliding mode controller is proposed to realize platoon control under the influence of external disturbance.Because the upper and lower bounds of a function are usually different,this chapter designs different adaptive laws for the upper and lower bounds of external disturbance.The coupled sliding mode control algorithm is used to realize the platoon control of interconnected vehicles under the influence of external disturbance.In order to avoid the influence of initial spacing error on the stability of platoon systems,a modified constant time headway policy is further proposed,which transforms the spacing error with arbitrary initial value into a new spacing error with zero initial value.The effectiveness and feasibility of the proposed algorithm are verified by numerical simulation.For the platoon systems with time-varying uncertainty,considering the chattering problem of traditional sliding mode control,a sliding mode controller based on disturbance observer is proposed to realize fast and accurate compensation for timevarying uncertainty and platoon control based on terminal sliding mode control.The fast convergence of uncertainties is achieved through the designed observer.In order to suppress chattering,a terminal sliding mode controller based on disturbance observer is proposed.In the process of string stability analysis,the counter proof method and piecewise discussion method are adopted without Laplace transform on the sliding surface,which can realize the platoon stability of terminal sliding mode control under the influence of time-varying uncertainty.Finally,the effectiveness and feasibility of the proposed algorithm are verified by numerical simulation and experimental platform.For the platoon systems with nonlinear uncertainty,considering the slow convergence speed of traditional control methods,a sliding mode controller based on multi power reaching law is proposed to realize the rapid convergence and platoon control of interconnected vehicle systems.By designing a second-order disturbance observer,the fast observation of nonlinear uncertainty is realized.Furthermore,in order to suppress chattering and improve the convergence speed of the systems,a sliding mode controller based on multi power reaching law is proposed.In the process of stability analysis,Lyapunov stability theorem and Laplace transform are adopted.The effectiveness and feasibility of the proposed algorithm are verified by numerical simulation and experimental platform.For the vehicle systems with unknown model parameters and external disturbances,considering the transient problem of coupled sliding mode control,a platoon control strategy based on neural network sliding mode control is proposed to achieve string stability.Firstly,neural network and disturbance observer are designed to effectively estimate the unknown parameters and external disturbances in the systems,which solved the difficulty in stability analysis of adaptive control method.In order to realize the string stability of interconnected platoon systems,the system model is transformed into a new system model about spacing error.The conditions for realizing the string stability of vehicle systems are given by using Laplace transform,which alleviates the transient problem of coupled sliding mode control to a certain extent.Finally,the effectiveness and feasibility of the proposed algorithm are verified by numerical simulation.For the platoon systems with input saturation constraints,considering the singular problem in terminal sliding mode control,a nonsingular terminal sliding mode controller is proposed to realize platoon control under input saturation constraints.The input saturation is compensated by adjusting a single parameter.Furthermore,a neural network is designed to approximate the nonlinear uncertainty in the platoon systems.The nonsingular terminal sliding mode controller based on neural network is adopted to realize the string stability of the platoon systems.The basis function in neural network only depends on the speed and acceleration of the leader.In addition,the nonlinear term of interconnected vehicle systems does not need to meet the matching condition.Finally,the effectiveness and feasibility of the proposed algorithm are verified by numerical simulation.