Patent ID: 8774966

Claim:
A surface treatment robot comprising: a robot body having a forward and a rear end, and a fore-aft axis defined therebetween; right and left drive modules, each drive module comprising a cup-shaped wheel having a substantially circular outer diameter, an annular tire having a substantially circular tire outer diameter and an inner diameter, the inner diameter fitting over the outer diameter of the cup-shaped wheel, and a tire thickness corresponding to the difference between the tire outer diameter and the outer diameter of the cup-shaped wheel; and a scrubbing element disposed along a cleaning width; wherein the right and left drive modules are disposed aft of the scrubbing element as the robot travels along the cleaning surface in a forward direction and the cleaning robot has a mass of less than about 10 kg, and the ratio of the tire thickness and the outer diameter of the cup-shaped wheel is in a range of 0.04 to 0.14.