Distributed Optimization Method And Its Application In The Performance Control Of Electric Vehicle Chassis

Most problems in real life can be solved by optimizing a series of complex objectives.However,with the development of science and the increasing complexity of optimization problems,the traditional centralized optimization method is no longer applicable.In recent years,the distributed optimization has achieved effective solution to complex optimization problems and broken the limitations of traditional optimization methods,in which the distributed autonomous make decision by local information.Based on the research results of domestic and foreign scholars,this paper studies the distributed optimization method,and verifies the effectiveness of the method in the electric vehicle chassis.In order to facilitate the research,this paper first establishes 7-DOF suspension model,2-DOF steering model,tire and brake model under the environment of MATLAB/Simulink,based on the knowledge of vehicle dynamics,automobile theory and the relevant data collected by multi-sensors.Then,according to the development status of distributed optimization and game theory,this papper proposes a game-based distributed optimization method.Based on the summaries of the game theory,Nash equilibrium and Pareto optimum,this paper combines the distributed optimization problem with game theory and establishes the state updating rules in the process of distributed optimization.In this paper,the performance indexes of suspension system,steering system and braking system in the electric vehicle are taken as control objects,and use fuzzy rules to determine the weight coefficients of vehicle chassis performance index in game optimization.Through the experimental analysis,it is found that the optimization effect of single game control in the face of complex systems such as automobile chassis is improved to some extent,but not obvious.Therefore this paper proposes an optimization method based on the control of the coordination between game theory and ATC(Analytical Target Cascading).The Nash equilibrium of game theory corresponds to the target value of ATC method and the result of game theory is regarded as the response value,then the distributed optimization problem is transformed into the problem of minimizing the difference between the target value and the response value.The optimization process is simplified.Finally,this paper establishes a Carsim-Simulink simulation platform.Then uses traditional optimization method,single game control method and coordinated control method of game and ATC to simulate and compare the chassis under the instantaneoussteering,emergency braking and steering braking conditions.The simulation results show that the two methods mentioned in this paper can improve the performance of electric vehicle chassis,and the latter has more obvious optimization effect.