Tactile pressure sensors to measure ground pressure from tractor tire loads

This article provides an assessment of tactile sensors used to measure ground pressures in soil from full-size tractor tires. To capture the tire’s soil pressure four 5400N tactile pressure sensors from Tekscan (Boston, MA) were utilized with a full-size agricultural tire in a laboratory setting. A servo-hydraulic loading system, capable of both load and displacement control, was used to apply known tire loads to the soil with the sensor placed at a depth of 45 cm in a soil bin. Two full-size tractor tires were tested; a traditional tractor tire, W800/70R38, and a recently developed low-aspect-ratio tire, IF800/55R46. The sensors were conditioned and equilibrated before placement at the bottom of the soil bin in the laboratory, while a two-point calibration scheme was used to calibrate the sensors, resulting in a confidence level of 99 %. The sensors were successfully utilized in measuring the tire pressure in soil, which included the contact area, average ground pressure, and peak ground pressure on loose sand. As expected, the experiments show the contact area, and average and peak ground pressure increase with increasing the tire load and inflation pressure. Comparing the two tires tested at different loads and inflation pressures showed only minor differences in the recorded contact area, average ground pressure, and peak ground pressure