Kinematic estimation method of ground vehicle center of gravity based on dynamic measurements

Bryan Ye-Wen Wang, Purdue University

Abstract

The identification of the center of gravity is crucial in determining the behavior and performance of the vehicle, which incorporates handling characteristics and rollover assessment. Conventional methods for locating the center of gravity are either based on labor intensive and subjective static measurements, or enable active road-handling control strategies that are designed for worst case scenarios. Despite the large number of methods that already exist for locating the center of gravity in vehicles, the use of operational data facilely available from measurements, presents a novel approach. This work focused on a near real-time method for identifying the center of gravity of a ground vehicle based solely on a kinematic approach and requires only a few dynamic measurements. A theoretical foundation of the method was developed and derived from the translational and rotational aspects of a simplified half-car model. By replacing the restoring forces with the equivalent inertial forces in the analytical model, an expression for the center of gravity was established, which does not explicitly depend on uncertain vehicle parameters. The final development stage of the method averages the extracted pitch motion of the vehicle by evaluating only the acceleration measurements that are opposite in direction to estimate the center of gravity in a ground vehicle. A simulation was conducted to evaluate the performance and robustness of the method by adding unbiased noise to represent more realistic measurements. The method was then demonstrated on a testing vehicle using a two-post vehicle simulator. The accuracy of the estimations proved to be a viable approach for identifying the center of gravity based purely on dynamic responses. Simulated damage and damping conditions on the testing vehicle was experimentally implemented to demonstrate the ability of the method to identify damage influenced by stiffness and damping, including the effects of these damages on the center of gravity.

Degree

M.S.M.E.

Advisors

Adams, Purdue University.

Subject Area

Mechanical engineering

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