Multi-Objective Optimization Design Of Vehicle Suspension Parameters Based On Game Theory

The primary purpose of this thesis is to analyze the effects of vibrations on the seat comfortable performance and road surface damage performance of vehicle as observed in the variation of different suspension parameters, and two types of multi-objective optimization methods aer using on these parameters design.The paper presents a 3-D vehicle suspension dynamic model with eight degrees of freedom, including seat vertical motion, suspension vertical, pitching and rolling motions and wheels vertical motions. A D'Alembert principle is used in order to obtain the differential equations of motion of the system. In the case of a passive suspension system which vehicle moves at a constant velocity v = 20m/s, obtaining three type road surface models on A, B, C grades based on the guidelines provided by ISO-2631 with Matlab/Simulink environment. Through modal superposition method for solving equations, get the modal characteristics of the vehicle and freedom various displacement, velocity, acceleration vibration response result on each road grades. Within the parameters set in suspension, analysis of the seat suspension, wheel stiffness, damping parameters on the performance of vehicles are given.Establish the multi-objective optimization model for vehicle suspension, based on the objective functions is seat comfortable and road surface damage; the design variables are stiffness and damping values of seat and suspension. With the methods of fuzzy optimization and game theory decision-making: Based on fuzzy math method, forming 2 types fuzzy opinion functions solve the multi-objective optimization model; based on game theory, establish Nash equilibrium model, solve the multi-objective optimization model. From the results, that the comfort performance of a suspension seat can be considerably enhanced by 20-30%. The results showed reasonably good agreement between the model results and the measured data.Under the Visual FORTRAN environment, design the program for solving dynamic response of 8 degrees of freedom suspension, multi-objective optimization on game theory design and fuzzy design. An example is given for verification of these approaches.The Game theory method is formulated for the optimization of vehicle passive suspension. Developed and enriched the methods of suspension system design.