Nonlinear dynamic analysis and experiments of a pressure self-regulating device for hydraulically interconnected suspension systems

Hydraulically interconnected suspension (HIS) systems have increasingly drawn attention because of its superiority on improving anti-rollover stability and ride comfort, but due to inevitable inner leakage, the unwanted static tilt of vehicle body caused by the pressure difference between two independent hydraulic circuits limits its application. This tilt problem will greatly reduce the driving safety and even lead to the rollover accident. In this study, a new pressure self-regulating (PSR) device is proposed to address this tilt problem, including its system design, manufacture and experimental validation. The structure and pressure self-regulating principle for this PSR device are introduced in detail first, and the nonlinear model is developed based on mechanical-hydraulic coupling equations. Moreover, the developed model is validated by bench tests; based on this, the parametric analysis is implemented to reveal the impacts of the key parameters of PSR device, including equivalent stiffness and clearance height, on the pressure difference threshold and the time delay. Also, the simulations and experiments from the perspective of the whole vehicle integrated with PSR device are carried out, which demonstrates that PSR device can automatically eliminate the tilt of the vehicle body by balancing the pressure between two hydraulic circuits of HIS system without deteriorating the anti-rollover stability and ride comfort.