Direct Tire Grip Sensing Based on Wheel Speed Fluctuation

This paper proposes direct tire grip sensing method based on wheel rotation speed fluctuation. Tire skid caused by loss of grip excites tire vibration. Therefore the vibration modulates tire rotation and causes wheel speed fluctuation. The wheel speed fluctuation is sensed by a wheel speed sensor. And the vibration frequency component is detected by frequency domain analysis such as FFT, wavelet transformation, etc. This paper presents effect of the proposed method through results of frequency-domain analysis on experimental data gathered by a chassis dynamo type tire testing system.