| In the course of vehicle movement, the change of the state of the vehicle movement is due to the change of the tire force at the ground. At the same time, the driver is the most intuitive perception of the changes in force. Suspension system, as an important part of the automobile chassis, is responsible for the transmission of the force between the tire and the cockpit. Therefore, the performance of the suspension system can be measured objectively by the moving state of the vehicle, and can also be measured subjectively by the driver’s driving experience. In the real vehicle design, due to the presence of geometric error, installation error, the actual hard point has certain fluctuation and uncertainty which cause the suspension K&C characteristic has fluctuation. This small change may bring about great change for car performance.In this paper, a vehicle front suspension is used as an example. Through the bench test, we can get the K&C characteristics of benchmarking vehicle suspension. Considering the development platform and comparing with the local suspension K&C data base, we select a certain suspension K&C characteristics as the standard K&C characteristics, that is, the target K&C characteristics of the suspension. The virtual prototype model of front suspension was established in ADAMS/View software according to the parameters of the suspension model and the constraint relationship between the components. At the same time, taking into account the interaction between the ADAMS/View and the Matlab, the program interface between the two software is established. Through the sensitivity analysis of the model by using ADAMS/Insight software, we could get the hard points which had significant impact on K&C characteristic and we set these hard points as the suspension optimization design variables. In the next step, we completed a multi-objective optimization program based on interval analysis in Matlab software to reduce the fluctuation of the wheel positioning parameters, by taking into account the errors in the production, manufacturing, installation process, the standard K&C characteristics and the constraint interval of suspension hard points. Finally, through the continuous iteration of the optimization process, a set of optimal suspension hard points was obtained.The method has high precision, but the computation efficiency is very low due to a large number of interactive operations between Matlab and ADAMS. In order to improve the efficiency of the problem, according to the rigid multi-body kinematics theory, a mathematical model of the front suspension was established, and the correctness of the mathematical model was verified by comparing with the ADAMS/Car model. Meanwhile, the sensitivity analysis method of Sobol was used to analyze the sensitivity of the suspension hard points. Finally, by calling the Matlab model through the optimization algorithm, the computational efficiency was improved, but compared with ADAMS/View suspension model, the accuracy was reduced.Through the verification of the optimal hard point, it is found that the fluctuation of K&C characteristics is reduced under the premise of considering all kinds of errors. This makes the design of the suspension K&C characteristics closer to the standard K&C characteristics, has a stronger robustness. Through the vehicle handling and stability test, it is found that the optimized vehicle performance fluctuation range is significantly reduced, and the robustness is significantly improved. This method has high practical significance, and provides theoretical basis for the design of the suspension in the future. |
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