Quote:
Originally Posted by Geek 2.0
Also, you would lose the 50%-71% of power, but not traction, so people pushing you shouldn't be too harsh if your wheels are locked. Given you won't have as much power pushing back.
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I hesitate to say you lose traction, because your wheels may still have the same grip on the carpet. But even if you lock your wheels, you only have a fraction of your "pushing resistance force". Unless you have a way to physically lock or articulate the rollers as describe in the paper I linked above, up to half of your traction is wasted on rollers that simply spin.
Take a square robot with one omniwheel (rollers perpendicular to the drive direction) on each side. To move forward, two wheels are doing the work, and two wheels are spinning their rollers and contributing nothing. The scenario is identical if we brake our wheels and another robot tries to push us. Two wheels will give us traction on the carpet, but the other two give us nothing.
If the robot moves diagonally, all four wheels move, but all of the rollers spin some. This results in a 1/(sqrt(2)) thing, which is where I get 71% power/traction.