Stability Research And Suspension System Optimization Of Motorcycle Based On Multiple Working Conditions

Due to insufficient attention to early research and development of domestic motorcycles,its dynamic performance under non-linear motion conditions is significantly different from similar products in developed countries.Therefore,in order to enhance the product competitiveness of my country’s motorcycles,it is necessary to carry out related researches on the dynamics of motorcycle suspension systems under non-linear conditions.Taking a domestic motorcycle as the research object,aiming at the wobble and weave problems of the suspension system when the motorcycle is running at high speed under non-straight working conditions,a motorcycle dynamics model and control system model are established.Simulation analysis,using sensitivity analysis and multi-objective optimization methods,complete the optimization analysis of suspension system parameters,compare the target response results before and after optimization,and use root locus theory to verify.The main research contents are as follows:(1)On the basis of domestic and foreign research,use MATLAB/Simulink to establish a control system model,and obtain through simulation whether the deviation between the established model’s driving path and the preset path is within the allowable range,thereby verifying the established human-vehicle The correctness of the closed-loop control model.(2)The Lagrangian method is used to derive the motorcycle motion equation,the motorcycle multi-body dynamic model is established and the dynamic simulation analysis is completed.The simulation phenomenon is basically consistent with the motorcycle jitter problem.(3)Aiming at the vibration problem of the motorcycle,establish a mathematical model of the optimization problem,compare and analyze the characteristics of each optimization algorithm,and select the NSGA-II algorithm to complete the optimization analysis of the front suspension system.After optimization,the extreme values of the yaw rate and lateral acceleration of the center of mass of the front wheel were reduced by 25.6% and 31.5%,respectively,and the vibration problem of the motorcycle was significantly improved.(4)Comprehensively consider the problems of jitter and sway,carry out sensitivity analysis on the design parameters of the motorcycle’s front and rear suspension systems to identify key parameters.Based on the sensitivity analysis,the optimized design parameters are obtained.Compare and analyze various optimization algorithms,and select the NSGA-II algorithm to complete the multi-objective optimization of the design parameters of the front and rear suspension systems.After optimization,the steering system center-of-mass position roll rate is reduced by 27.1%,the steering system center-of-mass position yaw rate is reduced by 17.6%,the vehicle’s center-of-mass position roll rate is reduced by 5%,and the vehicle’s center of mass position yaw rate is reduced by 15.2%.The shaking and swaying problems of the motorcycle are solved.(5)Compare and optimize the performance indicators of the front and rear motorcycles,and use the root locus theory to compare and analyze the jitter and swing mode stability of the front and rear motorcycles.The results show that the motorcycle jitter and rocking modal stability after optimization are better than those before optimization,and both are in the stable region,which verifies the feasibility and effectiveness of the optimization scheme.Through the analysis of the front and rear suspension system parameters of the motorcycle,and the sensitivity analysis method,the suspension design parameters that affect the dynamic performance of the front and rear suspension respectively are determined.Aiming at the jitter problem of the front suspension and the swing problem of the rear suspension,multi-objective optimization of the design parameters of the front and rear suspensions was carried out to solve the jitter and sway problems of the suspension system when driving in a non-straight line,and the driving stability of the whole vehicle Obviously improved,with higher engineering application value.