Research On Suspension Hard Point Design And Performance Optimization Based On Virtual Prototype And K&C Bench Characteristic Test

The suspension system of automobile is an important system of automobile chassis.The suspension system determines the driving stability and ride comfort of automobile chassis.The hard point of automobile suspension refers to the key geometric elements of suspension system,steering system and wheel,which can be divided into structural hard point and performance hard point.The chassis performance,especially the handling performance,is greatly influenced by the inclination angle,the back inclination angle and the inward inclination angle of the pin,the contact position of the tire,the stiffness of the spring,the stiffness of the Bush and the damping of the shock absorber.In the process of automobile development,the performance of suspension is often determined by comparing the control and comfort of the basic vehicle type.The suspension performance is optimized and improved by measuring the hard points and parameters of the suspension.ADAMS,as a typical software representative of virtual prototyping technology in the simulation and analysis of vehicle system dynamics,can carry out the K&C analysis of multi-rigid body suspension and the simulation analysis of the control and stability characteristics of suspension dynamics.The simulation results of the suspension model are close to the real vehicle measurements.Suspension Kinematics and Compliance Test Bench is a basic test platform for suspension development.It is mainly used to measure the geometric kinematics characteristics of suspension and steering system and the Compliance data under various stress conditions.These characteristics and data affect the integrity to a great extent.Vehicle handling and stability level.K&C test results can provide auxiliary validation for CAE analysis software such as ADAMS.By adjusting the input parameters of the software,the analysis values of the software are consistent with those of the bench analysis,and the accuracy of the simulation is improved,which provides strong support for the design and test development.Based on the design of an SUV project,the typical structure of McPherson suspension is selected as the foundation structure of the front suspension,and the popular E-type multi-link suspension is selected as the foundation structure of the rear suspension.According to the vehicle’s sales scenario,an SUV model is selected as the foundation vehicle,and the hard point of the foundation vehicle is obtained through the disassembly and measurement of the foundation vehicle.The stiffness of the spring,the diagram of the shock absorber and the stiffness of the bushing are tested through the bench test of the parts.The basic vehicle is placed on the K & C bench for K & C characteristic analysis,and the K & C characteristic parameters of the real vehicle are obtained.The simulation software ADAMS is used to simulate and model the suspension.The hard point of the suspension and the measurement parameters of the related parts are imported into the model.Combined with the results of the K&C bench of the base vehicle,the tire model and other parameters are adjusted,and the hard point of the measurement is corrected to obtain the suspension simulation model which is close to the base vehicle.Using the dynamic simulation module of the suspension system of ADAMS analysis software,the dynamics of the suspension system is simulated and analyzed,and the performance characteristics of the suspension system of the basic vehicle are obtained.The K&C characteristics of the foundation vehicle are analyzed by K&C bench and the results of dynamic simulation show that the foundation vehicle has some shortcomings,such as high side-tilt center of front and rear suspensions,small jump distance of rear suspensions and so on.The load distribution of the design vehicle is quite different from that of the base vehicle.In order to achieve the same support height as the base vehicle,the suspension parameters need to be adjusted.The hard points of the suspension are adjusted according to the optimization suggestions of the K&C analysis and dynamic simulation analysis of the base vehicle.The simulation results of the adjusted design vehicle are relative to the base vehicle.In order to verify the suspension performance after adjustment,a mule car is designed according to the setting parameters and hard points.After the prototype is completed,the K&C characteristics of the suspension are analyzed by K&C test bench.The analysis results of the base vehicle and the design vehicle bench are compared.It is proved that the suspension performance of the designed vehicle is quite obvious compared with that of the base vehicle.In addition,the subjective driving evaluation in the later stage further proves that the effect of suspension adjustment is obvious.The main advantage of this paper is that ADAMS model is optimized through the combination of ADAMS virtual analysis and physical bench analysis by comparing the bench results,so that the results of the model are consistent with the results of physical tests,providing an accurate optimization direction for later design optimization,and confirming the performance improvement effect after suspension optimization through subjective test comparison of control characteristics of vehicles before and after optimization.It has accumulated experience for the forward design and analysis of the suspension in the future,and has also formed a relatively complete suspension design and development process,providing a good guidance and reference for the later suspension design and development and optimization work.The model of reverse optimization through K & C test is the basis for the later extension development of the platform vehicle type,on which the development and optimization of the suspension can obtain a result close to that of the actual vehicle.