An Investigation of the Pulse Steer Method for Determining Automobile Handling Qualities

The use of pulse steering tests for assessment of handling qualities was investigated using a simulation of a comprehensive, nonlinear four wheel model of an automobile. Evaluations were conducted using frequency response functions of yaw rate and lateral acceleration obtained by FFT processing of the simulated response. In addition, as suggested by the work of Mimuro et al [1], four parameters (steady state yaw rate gain, yaw rate natural frequency and damping ratio, and lateral acceleration phase lag at 1 Hz) that characterize these response functions were also obtained by curve fitting techniques. The effects on accuracy of the response functions and the four parameters of variations in pulse shape, duration, and magnitude were investigated.

Results from the simulated pulse steer test were compared with those from simulated swept sine steering tests. On the basis of these comparisons, it appears that pulse testing offers accuracy and repeatability at least comparable if not better than that of the sine test method. In addition, pulse steer testing may offer significant time savings and the possibility of using shorter test tracks.