Optimal Damping Design of Heavy Vehicle with Interconnected Hydro-Pneumatic Suspension

The optimal damping design of roll plane interconnected hydro-pneumatic suspension is investigated, in order to improve vertical ride and road-friendliness of heavy vehicles, while maintaining enhanced roll stability. A nonlinear roll plane vehicle model is developed to study vertical as well as roll dynamics of heavy vehicles. The damping valves and gas chamber are integrated within the same suspension strut unit to realize compact design. The influence of variations in damping valve threshold velocity on relative roll stability is explored, under centrifugal acceleration excitations arising from steady turning and lane change maneuvers, as well as crosswind. The effects of damping valve design parameters on the vertical ride vibration and vehicle-road interaction characteristics are also investigated under a medium rough road input and two different vehicle speeds. A performance index is developed based on RMS sprung mass bounce acceleration and dynamic load coefficients (DLC) due to left and right tire loads. The design parameters of compression and rebound damping valves are optimized to minimize the performance index, while remaining improved roll stability. The benefits of the optimal damping designs on the vertical ride and road-friendliness of heavy vehicles are demonstrated, subjected to a wide range of road roughness and vehicle speed inputs. The shock isolation characteristics due to the baseline and optimal damping designs are further compared under discrete road bump inputs.