pic: My wheel/leg design

[Kevin Sevcik]

Originally Posted by mechanicalbrain

Yes thats exactly how it works. As to the retracting part. It would have to involve a mechanical function so i can keep the motors to a minimum. I want it to come around back so it can clear stairs and such objects. Finally, If I added wheels to the end of legs it would need to be some type of pulley system and then again I run into having more then two motors a leg.

Finally getting around to answering this... You could obviate the need for tons of extra motors, pulleys, chains, flexible shafts, etc by going with a large, well designed leg, and then putting a motor/gear case/wheel assembly on the end of it. Using FIRST parts, it'd be some sort of sturdy leg system with a Nothin'-But-Dewalts motor assembly attached to a wheel at the end of the leg. There are trade-offs, obviously. This makes your leg much heavier. But on the plus side, electricity is an awful lot easier to bend around corners than mechanical rotation.

[mechanicalbrain]

Wait would it still have both leg and wheel motion? If you can, add a picture of the design. Thanks.

[Kevin Sevcik]

Originally Posted by mechanicalbrain

Wait would it still have both leg and wheel motion? If you can, add a picture of the design. Thanks.

It's no design in particular. It's just an easier way of going about it. So no picture. Just imagine you have some sort of walking robot already. At the very end of each leg you put a wheel-motor assembly instead of a little rubber foot or what have you. Voila, a leg with a wheel on it.

It's not at all elegant, of course. But if you don't need a central engine driving the wheels, then it's a lot easier than the mass of U-joints, flexible shafts, or telescoping shafts you'd probably need otherwise. As a side note, if you're going to scale this up then at some point it becomes more efficient to use hydraulic motors to drive the wheels instead of electric ones. Though I'm not informed on the flexibility of high pressure hydraulic lines.