Tire sinkage measurement and entry angle calculation using stereo cameras

In the modern world the use of autonomous vehicles is growing more and more common. There are many applications for autonomous vehicles on deformable terrain, such as in military, farming, and mining but the problem with most established autonomous vehicle models is that they do not take into account the effect the terrain has on vehicle performance. To be able to accurately include these values in the vehicle model, they need to be directly sensed or estimated. One of the most valuable of these values is the tire sinkage. Tire sinkage is very important when it comes to terrain-vehicle interaction. The slip-sinkage relationship is an important factor in tractive performance. This paper is part of a larger project that is working on autonomy in conditions with deformable terrain and this paper presents on the methods employed to measure and find important values for the terramechanics of the model. This study specifically focuses on measuring the rut depth left behind after a tire travels over the terrain using a set of two stereo cameras. The sinkage is then used to be able to find the entry angle of the tire in the terrain.