Research On Energy-saving Control Of Vehicle Platoon Based On Distributed Model Predictive Control

In recent years,intelligent networked vehicles（ICVs）have become a hot technology in the field of transportation engineering,and one of its important benefits is to improve the economy of the transportation system.This topic takes the vehicle-to-everything（V2X）as the research background,takes the vehicle adaptive cruise control（ACC）and platoon control as the research objects,designs vehicles’energy-saving longitudinal control algorithm based on the switching system theory and the economic model predictive control（EMPC）method,analyzes the systems’asymptotic stability and string stability,and verifies the tracking accuracy and energy-saving effects of the proposed algorithm.The main work accomplished in this paper is as follows:First,the vehicular and platoon system models are established.The vehicle longitudinal kinematics model is established by feedback linearization,and a power-based polynomial energy consumption model is given.Based on graph theory,the vehicle platoon information flow model of multiple-predecessor following（MPF）topology is established.The trajectory tracking control target is designed based on the constant time headway（CTH）interval strategy,and the state equation of the error system is given,which provides the model basis for the controller design,analysis,and verification.Second,the design and analysis of the vehicular energy-saving adaptive cruise controller are carried out.Aiming at trajectory tracking,a state feedback control law with time-varying feedback gains is designed.Taking the accumulation of the fuel consumption per unit displacement of the ego-vehicle at each sampling time through the whole prediction horizon as the cost function and the feedback gains as the optimization variables,an energy-saving control algorithm is designed based on the economic model predictive control method.By constructing a common Lyapunov function,a range of the feedback gains is given,which would ensure that the tracking errors converge exponentially.Third,the design and analysis of the distributed energy-saving cooperative controller for vehicle platoons are carried out.Combined with the switching feedback control law and the economic model predictive control problem,the local optimal controller of each following vehicle is designed,and a distributed control framework is built accordingly.By constructing multiple Lyapunov functions and introducing the concept of average dwell time,the asymptotic stability condition of the platoon lumped error system is analyzed,and the selection range of the switching feedback gains and the lower bound of the average dwell time are given.In addition,the control algorithm is improved according to a constraint of the feedback gains under the condition ofL₂platoon stability.Fourth,the tracking accuracy and energy-saving effects are verified and analyzed by simulations.Under the condition of instantaneous speed fluctuation,the tracking errors’convergence and the platoon stability are verified.Compared with two benchmark algorithms that do not consider energy-saving performance,the energy-saving rate is verified in city and highway driving conditions,and the results vary from0.38%to 6.84%.At the same time,the conflict between tracking accuracy and energy-saving performance is analyzed,and the influence of control parameters and driving conditions on the control effects are explored.Furthermore,the safety of the control algorithm and its robustness against input disturbances and uncertain model parameters are verified.