Study On Co-simulation Of Vehicle Ride Comfort And Handling Stability

Nowadays, as the rapid development of automobile industry, people’s demandfor vehicle has not been only confined to good power performance and fuel economy,but the requirements of riding comfort and handling stability. This paper is based onmuti-rigid-body dynamics and principle of automatic control theory, usingMATLAB/Simulink software to study on the ride comfort and handling stability ofcars, and realizing the joint control for the two performances above with LQGalgorithm. The main research contents include:This paper studies on the ride comfort of1/4car model with2dof, half car modelwith5dof, the whole car model with7dof and car body-seat model with11dof.Respectively adding special road excitation in low degree model and random roadexcitation in high degree model, so it is comprehensive for different road models.Discussing the different application of Newton’s method and Lagrangian method forcar body model. In the study on the ride comfort of high degree car model, this paperdesigns parameter adaptive method with using subsystem nestification and packagetechnology, due to this method, we can avoid modifying the intrinsic matrix of carbody system repeatedly because of parameter modification in the design andconversion of cars, and provide certain theory basis for parameterized model. Thispaper sets up three schemes for seat modeling in the design of car body-seat modeland illustrates the necessity of modeling completely. Then combines thresholdoptimization method with riding comfort and optimizes parameters of suspension andseat, providing a good reference for the design of corresponding system in the car.Secondly, this paper studies on handling stability of motorcycle model with2dof,the whole model with3dof. Starting with front-wheel steering car, studies the stabilityof the models under the condition of low speed and high speed respectively. In thestudy of four-wheel steering, deducts control strategy of car’s rear wheels andexplains the disadvantages of the constant angle step input or the traditionalproportional input for the front and rear wheels respectively, then uses the feedbackcorrection with car speed and yaw velocity. At the same time, this paper verifies theconsistency of solving with state equation and Cornering force, it is convenient forjoining nonlinear tire. In the study of nonlinear model, joins Unitire tires and MagicFormula tires, we can conclude that the handling stability of nonlinear model isgenerally better than linear model’s and illustrates the research significance of thenonlinear model. At the same time, the application of model reconstruction methodsolves system divergence problem because of the existence of algebraic loop inhandling stability model, and deduces its theoretical origin, so this paper provides alot of good solutions for the study of handling stability simulation.Finally, this paper studies on the joint control algorithm of vehicle ride comfortand handling stability, then chooses the LQG algorithm, based on1/4car model with2dof, through the analysis of car body mass center’s acceleration, tire dynamic displacement, suspension dynamic deflection illustrates which parameters should beconsidered. Then designs active suspension with LQG controller and compares withpassive suspension, illustrates that both ride comfort and handling stability of car withactive suspension are better than passive suspension’s, and the study has importantresearch value.This paper solves lots of problems in car ride comfort and handling stability,perfect the inner part of the problem in this field of the research, has some certainreferences value for car design and conversion.