Road profile estimation using vibration signal in variable speed conditions

The road profile estimation scheme is introduced in this paper, leveraging vibration signals measured at the unsprung mass, adaptable to varying vehicle speeds. A quarter-car model is employed to establish a transfer function between the unsprung mass acceleration and the road profile. Given that the road profile is inherently spatial, the challenge of non-uniform spatial intervals under varying speed conditions is addressed. Sampling conditions based on nonuniform sampling theory are derived, ensuring the accurate reconstruction of original road profiles. It is proposed that the temporal sampling frequency should be determined by the harmonic mean speed over the sampling period and the maximum spatial frequency of interest. Through simulations, the range of vehicle traveling velocities and temporal sampling frequencies essential for precise road profile estimations is delineated.