Facility for Complete Characterization of Suspension Kinematic and Compliance Properties of Wheeled Military Vehicles

As part of their ongoing efforts to model and predict vehicle dynamics behavior, the US Army’s Ground Vehicle Systems Center procured a facility in two phases. The facility is called the Suspension Parameter Identification and Evaluation Rig (SPIdER) and has a capacity covering all of the military’s wheeled vehicles, with vehicle weights up to 100,000 lbs (45,400 kg), up to 150 inches wide, with any number of axles. The initial phase had the ability to measure bounce and roll kinematic and compliance properties. The SPIdER is the companion machine to the Vehicle Inertia Parameter Measuring Device (VIPER) which measures the inertia properties of vehicles of similar size. In 2015, the final phase of the SPIdER was completed. This phase includes ground plane wheel pad motion so that lateral, longitudinal, and aligning moment compliance and kinematic properties can be measured. These capabilities greatly enhance the SPIdER’s features, giving it the ability for making complete suspension and steering system kinematic and compliance measurements. Horizontal forces and aligning moments can be applied up to the limits of tire slip. Longitudinal forces are applied at the ground plane. The vehicle is driven onto the SPIdER and the body is restrained to a rigid T-bed. The test sequence can be performed in a few hours, and is done with the vehicle body stationary and the ground plane moving under the tires. The slight vehicle body motions are measured and this motion is accounted for in the calculations of suspension parameters. This paper describes the new capabilities of the SPIdER, including an overview of the new design features, control schemes, and measured quantities. Results from a sampling of various SPIdER tests are presented.