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This paper describes the design and operation of a facility for measuring vehicle center-of-gravity height; roll, pitch, and yaw moments of inertia; and roll/yaw cross product of inertia for a broad range of test specimens. The facility is configurable such that it is capable of measuring these properties for light, single axle trailers; long, heavy vehicles; and tank turrets. The design was driven by the need for accurate, repeatable measurement results and the desire to have a single facility capable of making measurements on a broad range of vehicle sizes.

The Suspension Parameter Measurement Device Model 7547 (SPMD Model 7547) has been designed and built for the purpose of measuring displacements and forces acting on the road wheels of a vehicle. These displacements and forces may be due to movement of the vehicle body (kinematic), forces occurring in the plane of the road (compliance), or due to movement of the steering wheel (steering). The SPMD Model 7547 tests the entire vehicle as a unit and provides a “black box” determination of the suspension characteristics in terms of input/output relationships. This data can then be used in the simulation of the performance of light cars and trucks.

The purpose of this paper is to give a description of using the new type Suspension Parameter Measurement Device. The design philosophy and specifications are elaborated on in another SAE paper entitled “Design of a New-Type Suspension Parameter Measurement Device”. The importance of using this new machine will be addressed in this paper. Because of the ease of use for this new device, testing can be accomplished in hours. To check repeatability, repeat testing can be done in a short period of time. This rapid testing is the main advantage of the new generation of SPMD's. The new SPMD collects raw data from transducers. All data are stored in the computer. Some are used directly to generate graphic outputs. Some are utilized to calculate wanted parameters. Graphs are generated so that some characteristics can be scrutinized. Parameters can be presented either by points or by cross plotting in graphs.