pic: What's going on here?

Originally Posted by gblake

Are you guys who are saying that a crab will stay in, or mostly in, the wheel's static friction domain, trying to tell me that crab drives are going to be able to perfectly match their wheels rotation and orientation with the bot's motion vector (speed and direction) AND then, when they want to turn, will be able to magically have the wheel trace out an arc without slipping sideways in the least????

The last time I looked, wheels travel in straight lines and turning a bot required the wheels to follow an arc. Twisting the wheel (even slightly) to cause it to travel in an arc would seem to involve a bit of slip (did I mention that the wheels' rotation and direction have to stay perfectly matched with the bot's velocity vector? - That's the velocity vector that you are trying to change as you turn...).

Color me dubious that a Lunacy crab drive will be able to do this at all, much less have an easy time supplying a non-trivial, static-friction advantage to a Lunacy bot.

Blake

While your concerns are valid, you're skipping a few factors. One being traction control, which will be clarified once we get it working. Another being individual wheel power. Individually powered wheels will be able to "power through" turns, much akin to an all-wheel drive car, or a vehicle with sufficiently advanced traction control.

A decently intelligent thing to do with a crab in Lunacy would be to keep the bot in 4 wheel steering mode, and have it act like a car. This allows for the options of doing "crab" (or side to side) motions whenever the situation requires it. A simple combination of a gyro and individual wheel motors will allow a crab to go in any direction regardless of the trailer.