Measurement of three-dimensional vehicular motion to assess the dynamic performance of safety structures

Abstract

Measurements system of three-dimensional motion of an impacting vehicle were studied. Through the review of existing systems, a nine accelerometer array was found to be a both stable and economical system. This system includes several sets of six, seven, and eight array systems. Each of these latent systems was studied. System differential equations of the latent systems were developed. Methods to simulate the error propagation and to remove the errors were developed. Using the methods and six test files from the Texas Transportation Institute, sytem fidelity studies were conducted. It was found that system equations of all of the six array systems were numerically unstable while all of the eight array systems were stable. System equations of some of the seven array systems were stable while some were unstable. Using the findings, a fail-safe feature was added to the basic nine array system. Software to describe the motion of the vehicle and to obtain the major risk indices was developed. Calibration methods used to identify the coefficient matrices of the Laboratory System Equations were introduced.