Nonlinear dynamic modeling and ride performance analysis of a mode-switching hydro-pneumatic suspension for mining dump trucks

Heavy mining dump trucks are subjected to severe road excitation and large payload variations, which make it difficult for conventional passive hydro-pneumatic suspensions to achieve satisfactory ride performance. To address this issue, this study proposes a mode-switching hydro-pneumatic suspension with four discrete stiffness-damping modes realized by the coordinated switching of two accumulators and two throttling branches. A nonlinear dynamic model of the suspension is established by considering gas compression, chamber pressure variation, throttling flow, check-valve switching, and friction. To evaluate the mode-dependent vertical ride performance, the suspension model is integrated with an effective road-input model considering tire enveloping and a two-degree-of-freedom quarter-car model in an AMESim-MATLAB/Simulink co-simulation framework. Static and dynamic bench tests are carried out to validate the model. The results show that the proposed suspension exhibits clear nonlinear and mode-dependent dynamic characteristics, enabling staged adjustment of equivalent stiffness and damping. The quarter-car-based simulations indicate that the influence of suspension mode is more significant under full-load conditions. Under severe road excitation, the soft-stiffness/high-damping mode provides the best vibration-isolation performance. The experimental results agree well with the predicted overall trends, confirming the validity of the proposed model. This study provides a practical suspension concept and a validated modeling framework for ride-oriented design of hydro-pneumatic suspensions for heavy-duty mining vehicles.