Robust Optimization Design For Ride Comfort Of Articulated Vehicle

As an important performance of articulated vehicle the ride comfort directly affects driver’s comfort and physical fatigue, furthermore influences the driving safety and others vehicle safety. Besides the ride comfort also has important influence on fuel economy and the fatigue of the vehicle components. Therefore improving the ride performance of articulated vehicle is of great significance by scientific and reasonable optimization design methods. The variability between design value and actual value emerges in manufacturing and assembling process. The variability is defined in terms of tolerances. The effects of tolerances in traditional optimization process always are transferred to objective function and constraints, which will lead to the failure of optimization results in reality application. Given this, this paper choose the robust design method, which based on tolerances analysis principle, to optimize the ride performance of articulated vehicle. The optimization method considering the tolerance of design variability made the results maintain robustness. The main research contents are as following:(1) Building the9degree of freedom vibration model of articulated vehicle and road surface excitation model. We deduced the differential equation of vehicle model with Lagrangian dynamic methods and solve the each freedom acceleration> SWS(r.m.s. value of Suspension Working Space) and DTL(r.m.s. value of Dynamic Tyre Load) response according to random vibration theory.(2) Analyzing how the suspension stiffness and damping、saddle position parameters、speed、and road surface grade affect the vehicle ride comfort. Then the paper build the quadratic equation of ride comfort optimization objective and constraints function with quadratic regression orthogonal combination test, which prepares for optimization process.(3) Considering the variability design variable effects on optimization process, this paper choose the parameter which have most important influence on ride performance and build the robust optimization mathematical model based on tolerance analysis principle to optimize the ride comfort. For verifying the superiority of the robust optimization, this paper also optimized the ride comfort with determinacy method. And then author comparative analysis the determinacy and robust method about the robustness of objective and constraint functions, under the circumstances of design variables having variability. The analysis results show the better robustness of the robust optimization based on tolerance analysis principle and also are better fit for reality.(4) We have an simulation on the seat surface acceleration, SWS, DTL, with the time-domain vehicle model that have been optimized, under the conditions of different speed and road surface grade. The simulation results demonstrate the optimization results have a satisfied performance at different speed and road surface grade.