Global Sensitivity Analysis And Optimization Of Hydraulic System Parameters To Hydraulically Interconnected Suspension Dynamic Response

The research of the paper is from National Natural Science Foundation of China(51275162) "Research on Control Strategy and Intelligence Optimization of Interconnected Suspension and Steering System".The suspension system can buffer the impact force from the uneven road surface to the frame or the body, and attenuate the vibration so as to ensure the vehicle running smoothness. As a new advanced suspension system, the hydraulic interconnected suspension system can be used to configure the stiffness and damping of the suspension independently, which can improve the handling stability of the vehicle without affecting the ride comfort. Compared with the existing focal points and methods, the study that is focused on modeling and working on the steady state characteristics of the interconnection schemes is almost no sensitivity analysis of hydraulic parameters. Therefore, this paper launched a series of research on hydraulic interconnection suspension system.The sensitivity analysis of hydraulic parameters is carried out by using Sobol global sensitivity analysis method, and the key hydraulic parameters are chosen to carry out the orthogonal optimization analysis. The main contents of the dissertation are as follows:Firstly, a four-degree-of-freedom anti-roll half-car model is proposed in this paper, which is used to analyze and introduce the composition and working principle of the mechanical and hydraulic systems. Based on the coupling boundary conditions, the mechanical and hydraulic coupled system dynamic equations are derived in frequency domain naturally.Secondly, in order to get hydraulically interconnected suspension dynamic response, in first place, the inherent characteristics such as four mode shape and transfer function verify the accuracy and validity of the model. Then, different road surface model are set up to achieve response under different operating conditions such as body bounce acceleration power spectrum density and roll acceleration power spectrum density.Then, by applying a method of global sensitivity analysis, the sensitivity level of hydraulic parameter to bounce and roll response are carried out. The experiment design method this paper selected is Optimal Latin hypercube sampling method. In order to test the total effect of multiple parameters on the model results, Sobol global sensitivity analysis method is adopt to calculate the sensitivity level. The hydraulic parameter sensitivity under bounce and roll modes is sorted to value the key hydraulic parameters that have a significant effect on body acceleration output spectral density, and theoretical analysis for all these to verify the rationality of the results.Finally, based on the results of sensitivity analysis, the orthogonal optimization analysis of hydraulic parameters is carried out. After selecting optimization variables and objective function, the Isight and Matlab cosimulation platform is established for multi objective optimization of bounce and roll modal body acceleration power spectral density response. Obtaining the optimized hydraulic parameter value, and it can be compared with before optimization curve of the hydraulic interconnected suspension dynamic response.