Actually, I like your idea of using a coupling as a clutch. It allows you to transmit more torque than a clutch bearing. I was merely trying to point out that there is more than one way of doing what you wanted to do.
Really, I've never ordered those, so I'm not sure if they could be adapted to work. You might be able to weld a gear around the clutch bearing, but it would probabaly damage the internal workings. I'm not really sure.
I understand that it's the first design, but you'd probabaly want to make the coupling smaller.
I'm sure it'd probabaly be the loudest robot on the field though with the constant clanking.
I thought about designing a belt-driven CVT, but the physics involved would be very complex, too much stuff that needs to be very precise. Basically, a belt-driven CVT works off a very similar principle as your clutch. You have a spring that applies a known force to half of a v-belt pulley. The other half is mounted permanently. Basically, as the robot goes faster, the half begins to separate (applies a centripetal force to the spring), thereby decreasing the radius. With that said, you can achieve anywhere between a 1:2 and 2:1 gear ratio.
I'm not sure if such an idea has yet been implemented on a FIRST robot, but I'd be willing to work through the math and find the correct parts if I had someone to draft it up for me
Quote:
Originally posted by ahecht
Very interesting. Another method I've seen for coupling two motors whose speed needs to be independent of each other is the modified planetary used in the Toyota Prius.
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From what I understand of the Prius, the CVT in the Prius is used to split the torque between the wheels and the generator. Their are three modes of the prius:
In the cruising mode, the CVT splits the engine torque between the drive shaft and the generator (generators induce a negative torque while they generate electricity). The generator, in turn, charges the batteries of the vehicle.
In high-acceleration mode, the CVT splits the engine toruqe between the drive shaft and the generator as before, but the electricity generated is sent back to the drive shaft where it powers a motor.
In low-speed and reverse, the vehicle is powered by the motor only.
I could be wrong, but I read a lot about it, and this is what most websites say. From a Physics point of view, this way would make sense.