Study On Rigid-Flexible Coupling Modeling, Simulation And Optimization Oriented To Performance Of Sport Utility Vehicle

SUV is the abbreviation of Sport Utility Vehicle. In the manufacture of high-speed vehicles, the vehicle handing stability and ride comfort is very important and is becoming the main criterion in vehicle performance evaluation.In this thesis, based on vehicle driving dynamics theory and multi-body system dynamics theory, combined with the technical parameters and structural features of a SUV, the rigid multi-body dyanmics models of each subsystems were established with ADAMS/Car module. Through a series of simulation, the rigid-flexible coupling dynamics model was built on the basis of the rigid multi-body dynamics model of the front suspension, and the multi-objective optimization design for wheel alignment parameters was carried on it. Then took all subsystems together to assemble full vehicle model for the simulation and analysis on handling stability and ride comfort of full vehicle.Firstly, based on the technical parameters and structural features of a SUV, by partly simplifying the practical structure of the SUV, in ADAMS/Car module, established the rigid multi-body dynamics models of each subsystem and analysised the syntagmatic relation between them, then assembled the all of the rigid multi-body dynamics models into the whole vehicle model via message exchanger.Secondly, on the basis of rigid multi-body model of front suspension model, through a series of simulation of replacing resilient bushing with rigid hinge joint, softening the upper/lower control arm and the horizontal stabilizer bar, etc., the results explained that the replacement of rigid hinge with resilient bushing, along with the softening of the lower control arm and horizontal stabilizer bar, have great impact to wheel alignment parameters, then established rigid-flexible coupling suspension model and made dynamical simulation and analysis on it.Moreover, combined with ADAMS/Insight, choosed appropriate key points coordinates of suspension structure as design variables, took the minimum value in the variation range of each wheel alignment parameters as single optimization objective, built a mult-objective function with "directly weighted unified objective function method", made multi-objective optimization design over front suspension in ADAMS/View. The results showed that the kinematic characterisics of the double wishbone suspension were improved to a certain extent.At last, on the basis of the optimized rigid-flexible coupling front suspension subsystem model, built the rigid-flexible coupling full vehicle model. Then according to national standard, simulation and analysis of full vehicle handling stability and ride confort were carried on it. In addition, the impact arosed by the replacement of the rigid multi-body front suspension subsystem with rigid-flexible coupling front suspension subsystem were also analysised by way of the comparison with simulation results on the rigid multi-body full vehicle model.Through the simulation calculation and the analysis, the built multi-body models of the SUV front suspension and the full vehicle are accorded with the real vehicle type on the main performance and on the variation trend. The models and the results are confirmed by the manufacturing corporation of the SUV type.