pic: FRC488's Octocanum Ver 2.0

[AdamHeard]

Originally Posted by Ether

The point midway between the translation follower wheels was said to be the center of rotation of the vehicle. To the extent that is true^*, you could extract vehicle rotation while translating.


^*The center of rotation likely shifts around especially if weight distribution changes as manipulators move.

Wouldn't that only be true while not translating? Translating would shift the center of rotation, would it not?

[theprgramerdude]

What's the maximum speed at which you can switch between Mecanums and high-traction wheels? Plus, about many switches can be performed before there becomes a serious air deficiency such that it is unreasonable to switch at all, assuming you have about 3-4 tanks at 120 PSI at the start.

[Dad1279]

Originally Posted by theprgramerdude

What's the maximum speed at which you can switch between Mecanums and high-traction wheels? Plus, about many switches can be performed before there becomes a serious air deficiency such that it is unreasonable to switch at all, assuming you have about 3-4 tanks at 120 PSI at the start.

YMMV, but we used 1 tank, (2) 1.5" bore, 2" stroke cylinders to switch between traction & mecanums, (2) .75" (6 or 8" stroke) to lift claw, and 2 small cylinders to deploy the minibot, and never had a want for more air.

[Ether]

Imagine a robot going around a circular track at constant speed such that it completes one lap every minute. The robot has a gyro mounted on it. The gyro rate will be 1 rpm, the same as if the robot were spinning in-place at 1 rpm.

I'll have to check the math, but I believe that with 3 followers mounted as shown, you can extract the vehicle's rotation rate (the same rate measure by a gyro) for any vehicle motion.

[AdamHeard]

Originally Posted by Ether

Imagine a robot going around a circular track at constant speed such that it completes one lap every minute. The robot has a gyro mounted on it. The gyro rate will be 1 rpm, the same as if the robot were spinning in-place at 1 rpm.

I'll have to check the math, but I believe that with 3 followers mounted as shown, you can extract the vehicle's rotation rate (the same rate measure by a gyro) for any vehicle motion.

Yes, but that's with 3 follower wheels. 488 only has two follower wheels measuring the floor, so I was clarifying as our swerve has two and there is no way we could infer rate from that (in fact we have to factor in the gyro rotation rate to even to get an accurate linear velocity).

EDIT: 488 actually has three follower wheels in that diagram, I was mistaken. Trivial calculation in that case.