Advanced Suspension Systems for Wheeled Military Vehicles

To allow wheeled military vehicles to travel at higher speeds on off highway roads, the primary suspension system needs to be semi-active or fully active. To develop a semi-active or a fully active suspension system for wheeled military vehicles, instead of the actual vehicle, a simpler and a better controlled system, meaning a quarter car test rig was used. The quarter car test rig consists of a tire, a spring, a Magneto-Rheological fluid (MR-fluid) damper, a double wishbone suspension system, and a mass representing a quarter car chassis. This paper documents the quarter car test rig design, its mathematical model, its MATLAB simulation results, and experimental test results collected on the actual test rig with the damper in the OFF state versus the semi-active state. The Ground-hook semi-active control policy was used to control the MR-fluid damper. This control policy significantly reduces the motion of the tire at its natural frequency.