Research On Multi-objective Optimization Control Strategy Of Adaptive Cruise Control System For A Sedan

The multi-objective optimization control strategy of adaptive cruise control system based on differential dynamic programming algorithm was designed.The reference sequence of differential dynamic programming algorithm was obtained by off-line optimization strategy using spline curve parametric method.This paper researched on the switch control law for the actuator of drive and braking system.The controller based on theory ADRC was designed.A joint simulation platform based on Carsim and Simulink has been set up to verify the feasibility of the control strategy.The main contents of this paper are as follows:Firstly,the research status of adaptive cruise control system decision-making method and actuator control method was studied.The research status of optimization control method of intelligent vehicle was also reviewed.Secondly,an adaptive cruise control strategy based on differential dynamic programming algorithm was designed.The vehicle motion state prediction model was established.Based on the vehicle dynamics,the cost function about vehicle driving safety,fastness,lateral stability,comfort and fuel economy was established.This paper proposes a Z-Sigmoid cost function normalization method and assigned the weights to the cost function.The differential dynamic programming algorithm was improved to increase the constraint on the control input,so as to realize the real-time optimization for the reference control sequences of adaptive cruise system.Thirdly,the off-line optimization algorithm for the reference control sequence of the adaptive control system was designed based on the three-stage and fourth-order Bspline curve parameterization method.The flat property of the vehicle kinematics model was analyzed,and the matrix calculation of parameterization of vehicle motion state was realized.The constraint based on vehicle dynamics was established and The initial reference control sequence needed for the differential dynamic programming algorithm under different conditions was obtained by using optimization software called SNOPT.Fourthly,the active disturbance rejection acurator controller of adaptive cruise control system was designed.The switching control law of the vehicle drive and the brake system actuator under different conditions was studied.The acurator controller based on active disturbance rejection theory was designed and simulated.The simulation results showed that the active disturbance rejection controller could achieve the precise follow-up to the control target.Fifthly,the Matlab/Simulink and Carsim joint simulation platform was set up and the control strategy of the adaptive cruise control system was simulated.For the road of different curvature,the steady state follow-up,the speed fluctuation follow-up and the emergency braking condition were simulated.The simulation results showed that the control strategy was effective.