Anti-rattle optimization design of vehicle suspension damper with damping stability constraints under uncertainty

With the advancement of vehicle electrification and intelligence, the complexity of suspension systems and hydraulic damper structures has significantly increased to meet stringent vehicle dynamic requirements. Consequently, damper rattle noise is more easily induced and represents a primary concern for passenger comfort. The damper vibration characteristics analysis and anti-rattle design optimization are crucial for improving the noise performance. In this paper, a hydraulic damper dynamic characteristics model with variable orifices flow property under disc valves deflections is developed, which employs the computational fluid dynamics method to calculate the orifices flow property under different disc valves deflections and to fit the flow coefficient function. Furthermore, the damping stability constraints are proposed and considered into the rattle noise optimization processes, which include the fluctuation percentage of the damping force and the idle stroke distance. Then, a generalized inverse cascade method is introduced for damper anti-rattle design, which combines large-scale and refined interval search strategies to achieve uncertainty optimization. Compared with the traditional damper dynamic simulation model with invariable orifices flow property, the proposed method demonstrates lower errors in representing both vibration and damping characteristics. The optimization results indicate that all design variable combinations within the Pareto solution intervals can optimize the damper vibration characteristics into a non-rattle level. Under all velocity conditions, the damping force fluctuations remain below 10%, and no rebound or compression idle stroke effects occur. Finally, the effectiveness and robustness of the optimization scheme are validated through a vehicle road test.