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Standard wheels can provide a zero (or rather, minimum possible) turning radius with appropriate drive. Tracked vehicles like excavators frequently turn in plac

by dpark 5y ago

Standard wheels can provide a zero (or rather, minimum possible) turning radius with appropriate drive. Tracked vehicles like excavators frequently turn in place with a minimal radius by turning their tracks in opposite directions. This action does not need spherical wheels. It doesn’t even need 4 independent wheels. The only thing you can get from spherical wheels that you can’t get from standard wheels with comparable drive is sideways motion, which granted, would be kind of awesome (zooming down the highway and switching lanes with no directional change), but also not actually that useful. You can also get a bit of this from independently-steerable wheels, as someone else pointed out. But that won’t get you sideways motion from a standstill if that’s somehow useful.

dragonwriter 5y ago
> You can also get a bit of this from independently-steerable wheels, as someone else pointed out. But that won’t get you sideways motion from a standstill if that’s somehow useful. You can actually get it from independently steerable wheels with AWD if they are mounted and driven independently (practical with an electric power system) rather than off a common axle; I’m pretty sure I recall concept vehicles (or at least designs) from various car companies with that design, for that purpose. The typical highlighted urban use case is zero-approach parallel parking. For autonomous vehicles, especially, it would make higher density but basically random access (and, therefore, not subject to easy blockage by small number of vehicle failures) storage possible > zooming down the highway and switching lanes with no directional change You probably can't get better than AWD with independently steerable wheels on an axle for this, because the limiting factor in how far you can change thrust direction while maintaining control at highway speed is going to be traction long before it is maximum wheel angle.

by dpark 5y ago

dragonwriter 5y ago

> You can also get a bit of this from independently-steerable wheels, as someone else pointed out. But that won’t get you sideways motion from a standstill if that’s somehow useful. You can actually get it from independently steerable wheels with AWD if they are mounted and driven independently (practical with an electric power system) rather than off a common axle; I’m pretty sure I recall concept vehicles (or at least designs) from various car companies with that design, for that purpose. The typical highlighted urban use case is zero-approach parallel parking. For autonomous vehicles, especially, it would make higher density but basically random access (and, therefore, not subject to easy blockage by small number of vehicle failures) storage possible > zooming down the highway and switching lanes with no directional change You probably can't get better than AWD with independently steerable wheels on an axle for this, because the limiting factor in how far you can change thrust direction while maintaining control at highway speed is going to be traction long before it is maximum wheel angle.