A measurement of the effect on drag force on a Botvac on medium loop pile carpet. The slider is absolutely needed for the Botvac to operate on this carpet in its present condition, in a high humidity environment. The slider works very well and the Botvac navigates easily. Without the slider the Botvac moves noticeably slower, exhausts the battery twice as fast and will get stuck in some places with wheels spinning.
To measure the drag force approximately, a string is attached to the bottom of the wheels, covered in slick tape, and pulled with a postal scale. Of interest is the difference in drag measured with and without the slider, rather than the actual drag experienced with drive wheel rotation. Because the wheels sink into the carpet, the string cannot be attached to the wheel axle or sides of the Botvac, as then the forward resistance of the wheels tilts the unit forward pressing the front into the carpet. A powered measurement with wheels driven by the motors is difficult because attaching a string to the back to measure the traction pull also distorts the unit stance.
3/8 in. thick Botvac slider (1/4 in. XV models)
4 pounds (1.81kg) of force was observed needed to move the Botvac with the slider, and 4.25 pounds (4 lbs. 4 oz, 1.93kg) needed without the slider. The slider makes only a 6 per cent reduction in the drag forces. The carpet presents a very borderline condition which is nonetheless critical to navigation.
