Vehicle Suspension Measurements: Evaluation of the Benefits of Dynamic over Quasistatic Kinematics and Compliance Testing

Abstract

Abstract Vehicle dynamics packages can be used to simulate handling or braking maneuvers that would otherwise need to be performed outdoors. Many of the parameters for these types of vehicle models are determined through kinematics and compliance (K&C) measurements. Machines that perform these measurements apply various forces or moments and measure the response of the vehicle. The rate that these forces or moments are applied can be quasistatic or dynamic. Machines that are capable of performing dynamic tests are more expensive due to the need for inertia compensation, sensors that can acquire data at higher rates, and larger actuators or hydraulic power supplies. However, it is possible that measurements of dynamic vehicle response may increase the fidelity of parameter identification, compared to the sole use of quasistatic tests. One reason that parameter identification may be more accurate is the rate of force and moment application in dynamic tests is more like those in the actual maneuvers that are desirable to simulate. A study was performed to determine where the advantages of performing dynamic K&C testing lie. Quasistatic K&C tests, along with dynamic tests performed at several frequencies up to 3.0 Hz, were performed on the front axle of a front-wheel drive compact sedan, using an MTS Systems High-Rate K&C Machine. Assessment of any advantages of dynamic K&C testing has been made through correlations of the vehicle response between dynamic and quasistatic tests.