It's not clear that this offers any advantage for how complex it is. The claimed advantage is being able to trade off speed for efficiency, but curves of both a

It's not clear that this offers any advantage for how complex it is. The claimed advantage is being able to trade off speed for efficiency, but curves of both are fairly flat. For mud, at max efficiency it can travel at 25 mm/s and at max angle 32ish mm/s with an error bar of 10 mm/s. That being said, efficiency does not seem to be good compared to wheels. At best, it's 0.1, which sort of corresponds to a rolling resistance of 0.9(higher is worse). Cars have a rolling resistance on soft sand of 0.2-0.4[0]. Of course this high efficiency was on mud, but their efficiency for sand is so close to zero I can't determine it without counting pixels in the graph. [0]www.engineeringtoolbox.com/rolling-friction-resistance-d_1303.html