Swerve Drive Modules

[msimon785]

Also, I know 1717 uses the main bent SM piece with open sides, in additional to two side plates which rivet on. This makes assembly way easier, but makes repair quite difficult. Of the two designs (one piece, three pieces), which is preferable? Also, would it be a terrible idea to weld the timing-belt pulley to the SM? I know it would warp considerably.

[Chris is me]

There is no way that you would be able to bend that module in one piece.

[42!]

What method are you using to hold The output shaft to keep the module standing straight? This tends to be one of the more important things to get right in swerve drive. As it is i don't see any method in place to hold the module against side force.

[msimon785]

Originally Posted by 42!

What method are you using to hold The output shaft to keep the module standing straight? This tends to be one of the more important things to get right in swerve drive. As it is i don't see any method in place to hold the module against side force.

I'm not sure what you mean. The output shaft infers the bolt holding the wheel/sprocket, correct? What do you suggest I add to prevent unwanted sheet-metal bending?

[42!]

I was actually referring to the shaft that the whole module pivots on, as it it i see it being held by one bearing at the top of the module, normally teams will have a second shaft around the drive shaft that the module turns on. Then this shaft can be held by some sort of bearing system that attaches to the robot.

[msimon785]

Originally Posted by 42!

I was actually referring to the shaft that the whole module pivots on, as it it i see it being held by one bearing at the top of the module, normally teams will have a second shaft around the drive shaft that the module turns on. Then this shaft can be held by some sort of bearing system that attaches to the robot.

Okay. Well, yes, in this design it is effectively held by one bearing. Where exactly do they place that second shaft? I can also, of course, just change it to a roller bearing, which are longer.

[42!]

The drive shaft is placed in the center of the shaft the module rotates on. In most systems there are two bearings hold the drive shaft. There should also be a system to hold the shaft the module pivots on. if your confused about this you should look at 221's Swerve system Revolution swerve http://www.andymark.com/ProductDetai...ctCode=am-0760
They have one of the more reliable swerve systems around

[akeisic]

Guess what team choose NOT to use a swerve drive this year? Wildstang! And it's practically been there signature for years.

It's typically about what goes on top of the drive train that makes the difference. Glad to see you're working the details BEFORE the season starts.

[staplemonx]

Has anyone ever build a two wheel swerve drive with omni's on the corners? Make the swerve wheels 2 or 3 inch wide on the center.

[Andrew Schreiber]

Originally Posted by staplemonx

Has anyone ever build a two wheel swerve drive with omni's on the corners? Make the swerve wheels 2 or 3 inch wide on the center.

I seem to remember a team doing something like that in 2008, can't name the team though. I would be careful about making the wheels 2/3 inches wide because the wider grippier wheels make rotating the modules more difficult.

[Gdeaver]

The current design shows several problems. It is not easy to make a module that can hold up to some serious stress. We have done swerve for 2 years now and this link will show a design that has proven very durable.
http://wiki.team1640.com/index.php?t...II_Drive_Train
It's only May. You have several months to refine the design.

[Ryan Himmelblau]

Originally Posted by akeisic

Guess what team choose NOT to use a swerve drive this year? Wildstang! And it's practically been there signature for years.

It's typically about what goes on top of the drive train that makes the difference. Glad to see you're working the details BEFORE the season starts.

The reason we chose 6wd this year was purely based off our strategy for this year's game. We deemed early in the build season that for this year, speed was far more important than maneuverability.

Every drive system has it's advantages and disadvantages. You should base your drive train decision off what will complete the task at hand the best, not on what is cool or different or easy.

During our initial brainstorming seasons we had at one time 8 different drive systems up that we were considering. Hooray for double sided white boards!

[Clem1640]

We've used Martin Gears' HM1616 (16 teeth, 16 Diametrical Pitch) miter gears for the last 2 years, but will probably switch to M1616 (not hardened) if we do this again. Gears have 3/8" unfinished bores. We cut our own keyways (finished bore gears are too expensive). We've had good experience with these.

Here's a view of our 2011 Pivot Module. Our Module includes the motors and angle sensor:

http://wiki.team1640.com/index.php?t..._annotated.jpg

Mass is 9.1 lb including motors, gearbox & sensor.