pic: All Terrain Swerve 1

[artdutra04]

So far this looks like a really neat idea.

The only problems I see that might be a problem with going offroad and all-terrain are the lack of ground clearance between the CIM motors and the ground, the "exposed" gears on the outside of the modules (although protected from the side, there's nothing on the bottom to prevent sand or grime from getting in there), and maybe the treads themselves.

I'd probably consider much wider treads with more traction to them, so that if traveling through something like sand, snow, or mud they don't sink out of sight. (Ever try to ride a bicycle through deep mud?) Wider treads will spread out the weight of the robot better, allowing for the robot to glide over the obstacles instead of sinking into them.

Originally Posted by Alex.Norton

I have thought a lot about the turning problem and had a couple of ideas. I thought about using another set of motors on each module to lift it up onto just one of the two pulleys. I also thought about making the shock absorbers to out of pneumatic cylinders, and put valves on it so that it could lift the modules onto one pulley. The other advantage of these is that it would make it easier to get up ledges.

I do like the idea of using three pulleys to get one point of contact but I'm weary of this because it wouldn't be stable in this set up with the second axis of turning. This is actually just a fun little CAD project that I'm working on. I'm trying to put together a bunch of different wierd drive trains together to give the younger kids on the team some ideas for next year.

Point contact would a complete 180 of what you need when going off-road and all terrain. You need more contact with the ground, to better spread out the load so you don't sink into the ground.

Originally Posted by 114ManualLabor

One suggestion: You're going to have trouble turning.

No it won't. This robot should have an excellent time turning, and I don't see any problems with it as is. In fact, with some sophisticated code it can be even more agile than a traditional swerve drive in it's ability to do complex curves and arcs without any side scrub.

All of the four swerve modules are all independently driven, which means you can have all your wheels turn in different amounts to almost perfectly turn using Ackerman steering. Since every wheel can turn independently, each wheel can turn the exact amount needed to eliminate any and all side scrub. Here's a quick illustration:



...Which would work exactly the same as the Jeep Hurricane concept car:


http://video.google.com/videoplay?do...03950591957346

[bear24rw]

http://www.robots.org/images/NASA_Am...yMarsRover.jpg

[SamC]

Originally Posted by artdutra04

...Which would work exactly the same as the Jeep Hurricane concept car:

...I want one!

Originally Posted by artdutra04

No it won't. This robot should have an excellent time turning, and I don't see any problems with it as is. In fact, with some sophisticated code it can be even more agile than a traditional swerve drive in it's ability to do complex curves and arcs without any side scrub.

Actually, if the motor couldn't even spin the tread (which it wouldn't, those things have practically no tourqe) then being able to do those complex curves wouldn't really matter. I was referring to the motor choice to spin the actual module, not the over robot turning ability.

[Alex.Norton]

I don't see how those motors don't have much torque. The CIM's have more than enough power for the drive on a 40-60 pound bot and the fisher price through a 256 reduction should have like 60 ftlbs. of torque which should be more than enough.

In any case the robot should be moving when turning the modules which will significantly reduce the turning force

[David Guzman]

Originally Posted by 114ManualLabor

(which it wouldn't, those things have practically no tourqe)

I think you need to work out your numbers again. The motors have quite a bit of torque. We used them to pivot our arm, which takes more torque than turning those modules. The only problem I do see with this motors is overheating, but thats a different story. In the end we changed them for globes but only because of the overheating problem. They had sufficient of torque.

[kibbs425]

If your really looking at doing this you may want to see about putting all of your gears in an enclosed gearbox with an output shaft that chain drives the wheel pulleys. This will help keep the gears clean and running better, i.e. not wearing down teeth because of grit contaminant. Also look at getting sealed bearings, with REALLY good seals. Girt contaminants can easily destroy any rotating part.

[zander_108]

I still can't understand how it matters how much torque it will take to turn those modules, as of the current rules, there are not 4 FP allowed.

Originally Posted by David Guzman

All of the four swerve modules are all independently driven, which means you can have all your wheels turn in different amounts to almost perfectly turn using Ackerman steering. Since every wheel can turn independently, each wheel can turn the exact amount needed to eliminate any and all side scrub. Here's a quick illustration:

this is in fact very true that it will not take much force to turn the modules, you might as well just use 2 BB motors and 2 globe motors.

[Brandon Holley]

Originally Posted by zander_108

I still can't understand how it matters how much torque it will take to turn those modules, as of the current rules, there are not 4 FP allowed.

I think this is being considered as a side project...not necessarily for competition