A Optimizing Study On Handling Stability Based On ADAMS

Along with the rapid development of vehicle technique and the continuous improvement of road condition,vehicle running speed increases significantly,and people pay much attention to vehicle's safety performance.So,the study on vehicle handling and stability which is closely related to vehicle's active safety is becoming more and more important.The traditional research method mainly use real car to do experiment.It wastes huge cost and some experiments are difficult to do because of its risk.Due to the fast development of computer technology and precision construction of the car dynamic model and the tire model over the past decade,it is possible and necessary to use computer simulation technology to study vehicle handling and stability.In this paper,by introducing the multi-body system dynamics theory and research methods,and multi-body dynamics software MSC.ADAMS to a prototype for a car,the author firstly establish a suspension and steering systems model.In order to make the model more vivid, the author does a simulation study on the movement characteristics of the suspension and steering system.The study includes movement characteristics of steering system under the suspension of beating and coupling, based on which the author made a suspension of related geometric analysis parameter changes curve. By using ADAMS/CAR through the revision of template parameters and the hard point,the author establish a front suspension systems,steering systems, rear suspension systems, brake systems, powertrain, body,tires,and other subsystems to set up vehicle model.From a number of factors that affect the handling and stability, the selected front wheel camber, rear camber, front suspension partial rate, front suspension damping ratio, rear suspension damping ratio as the optimization variables. And programming of the damping ratio and the partial rate for conversion of these abstract parameters of the component attribute value to the specific. According to the conclusions of other papers to calculate the relationship between the camber and the toe angle. Therefore, in the optimization process, you can change those specific component values according to the above relations.The authors select angle pulse input test as a virtual simulation project, and use Matlab to program for the simulation data. The relationship between Five parameters and the variable angle pulse input test scores is a five dimensions nonlinear function. With gradient method to find the five-dimensional extreme value, after two searches, and finds extreme points. The simulation graph in extreme point compare with that in origin, you can see significantly better vehicle stability.Finally, the authors use system identification techniques, with different second-order underdamped linear system to express different speeds steering dynamics of cars. By system identification, and more clearly reflect the characteristics of vehicle dynamics before and after optimization changes..