Research On Vehicular Platoon Algorithm Based On Adaptive Sliding Mode Control

With the rapid increase in the number of cars,traffic jams and environmental pollution have become serious problems faced by many cities.Intelligent transportation system,especially the development of vehicular platoon,can effectively solve these problems and improve road traffic flow and safety.However,in engineering practice,vehicles running on the road will suffer from the interference of road conditions,air resistance,wind speed and other external factors,the engine and other actuators will also fail due to wear,aging and other problems,and the vehicles will be constrained by their own physical hardware.The existence of these factors brings challenges to vehicular platoon control.Therefore,how to design control strategy to realize the smooth running of vehicular platoon has important theoretical and practical significance.The main work of this paper includes:Firstly,a second-order mathematical model is established for vehicular platoon problem with external disturbance,and a coupling sliding mode control mechanism based on prescribed performance is proposed.Adaptive control method is used to design adaptive law to estimate the upper limit of external disturbance of vehicular platoon.In order to study the steady-state performance and transient performance of vehicular platoon system at the same time,the tracking error of the system is constrained by the prescribed performance control method,and the transient state of vehicular platoon is studied through the convergence characteristics of the set performance function,such as convergence speed and overshoot,and steady state errors.Combined with the adaptive estimation of interference and the tracking error after conversion,a distributed coupled sliding mode control mechanism for vehicular platoon is designed to ensure the stability of a single vehicle and the stability of the whole vehicular platoon.The feasibility of the proposed control scheme is verified by MATLAB simulation experiments.Secondly,considering the dynamic characteristics of vehicles,a third-order mathematical model was established to eliminate the adverse effects caused by the actuator dead zone and faults,including the actuator faults with partial effective loss faults and deviation faults,and the vehicular platoon problems caused by external interference.The radial basis(RBF)neural network is designed to approximate the nonlinear dynamics of the vehicle,and the minimum parameter learning method is used to reduce the calculation of the network weight,thus simplifying the control algorithm.Based on an exponential spacing strategy,an adaptive sliding mode control mechanism was designed for distributed vehicular platoon system.The stability of a single vehicle and the whole vehicular platoon was guaranteed by Lyapunov stability analysis,and the effectiveness of the scheme was verified by simulation experiments.Finally,a third-order vehicle model was established for the problem of vehicular platoon subjected to actuator fault,asymmetric actuator saturation and unknown external interference.An adaptive control algorithm based on RBF network compensation was designed to estimate and compensate actuator fault and actuator saturation,eliminating the constraint that the unsaturated part of the actuator saturation model is known and monotonically increasing.The original exponential spacing strategy is improved to eliminate the assumption of zero initial tracking error.Based on this improved spacing strategy,an adaptive fault-tolerant control mechanism with prescribed performance is designed to realize finite-time stability of vehicular platoon.The transient and steady-state properties of the system are studied while ensuring the stability of a single vehicle and the whole vehicular platoon.Finally,the feasibility and superiority of the designed controller are verified by simulation and comparison experiment.