3 ms·
> but because I never could get the wheels aligned perfectly straight it would inevitably try to turn Hm. I don't think "wheels aligned perfectly straight" is
by kqr 4y ago
> but because I never could get the wheels aligned perfectly straight it would inevitably try to turn
Hm. I don't think "wheels aligned perfectly straight" is the actual solution. I wonder if there's some simple mechanism by which it could be made directionally stable, in the sense of continuously adjusting itself to go forward instead of turn.
- cdot2 4y agocastor wheels like on a bicycle/motorcycle?
- sokoloff 4y agoYou need the center of drag to be behind the center of mass (think “feathers on an arrow” as the mental model). Free castering front wheels with fixed rear wheels that develop progressively more drag as the yaw increases will help, but you’ve got to get the mass forward as well.
- kqr 4y agoWould castering rear wheels with mass (engine?) forward be simpler?
- sokoloff 4y agoI think you want non-castering rear wheels, because you want the side forces to be generated when the vehicle is yawing with relation to the direction of travel. As the sled starts to spin, non-castering rear wheels will tend to oppose the spin. (If anything, you might even want to set the rear wheels fixed and slightly askew [toed-in] to increase the drag while traveling in a straight line [with near-zero yaw angle].)
- WalterBright 4y agoA rudder might have worked. Also, at the time I had a pretty poor understanding of stability, and no understanding of "oversteer".
- Doxin 4y agoAngling the wheels slightly outward would at least work to course-correct if the weight of the contraption gets slung out. If the car leans left it'll have the most weight on the left-angled wheels, putting it back on all four wheels. The mirrored situation happens if the car leans right.