DYNAMIC 3D MEASUREMENT OF TYRE-TERRAIN INTERACTION

When studying terramechanics for wheeled vehicles it is important to understand the tyre-terrain interaction. However the tyre road interface is hidden from view by the terrain and tyre itself. This makes determining the interaction externally very difficult. Some progress has been made by embedding sensors in the terrain or the tyre carcass however these techniques only capture a very small number of points. The problem of measuring dynamic tyre deformation at the tyre road interface from inside the tyre has been tackled in previous papers, however in this paper we seek to extend these measurements to identify the impact that rolling tyres have on the terrain. This is accomplished by measuring the undeformed soil profile in front of a tyre, the carcass deformation inside the tyre and the deformed soil profile behind the tyre. Test data was captured with the so-called Tyre–Terrain Camera System (T2CAM) on the Terramechanics rig at Virginia Tech using prepared sandy loam as the deformed soil material. T2CAM consists of three calibrated stereo camera rigs, a six-component load cell, wheel angle sensor and wheel speed sensor. Computer vision techniques are used with the images to generate full three dimensional profiles of the two soil areas and the inside surface of the tyre as captured by the cameras. The testing aims to compare undeformed soil profile with the deformed soil profile with the added information about the contact patch area and wheel forces to quantify both the plastic and elastic soil deformation.