New AndyMark Products (Swerve & Steer module?)
 

I've noticed AndyMark coming out with some new products for the year, they actually just tweeted out a "Swerve & Steer" module.

Here is their new product page.

What do you guys think about the new products for the year? I really like the look of the swerve module, can't wait to see it in use on some robots.

Re: New AndyMark Products (Swerve & Steer module?)
 

So I since they announced I guess I can talk about it a little :confused:

I was able to hold one of these recently during a visit to AndyMark recently. I've never worked directly with swerve drive but I've held team's samples and such.

Keeping it short, this is the cleanest, lightest swerve module I've ever held and was kind of blown away by it. It has some nifty built in wiring options for potentiometers that I admired as well.

Re: New AndyMark Products (Swerve & Steer module?)
 

Thanks for posting that Evan, we're excited to see these in action this year. For those interested the product page now has pictures. http://www.andymark.com/product-p/am-3009.htm

Re: New AndyMark Products (Swerve & Steer module?)
 

These are a bit of a game changer....
$1300 buys you 4 swerve modules WITH motors!

Depending on the game, we may just have to buy some of these.

Re: New AndyMark Products (Swerve & Steer module?)
 

Am I seeing right that it also includes an encoder(not the absolute)?

Re: New AndyMark Products (Swerve & Steer module?)
 

I believe so!

Re: New AndyMark Products (Swerve & Steer module?)
 

A sensor on the back of the 775 with that much reduction after is going to be pretty sloppy imo.

The long cantilever on the bevel pinion worries me too.

Re: New AndyMark Products (Swerve & Steer module?)
 

Aren't you getting more precise control by reducing after the encoder instead of before?

Re: New AndyMark Products (Swerve & Steer module?)
 

Play in gears adds up.

Re: New AndyMark Products (Swerve & Steer module?)
 

These modules look really awesome. One question: what bearings are you guys using for the rotation, and what holds the robot's weight. I can't quite tell from the picture what's going on.

You care about the module's angular displacement, not the motor shaft's. There's some backlash in the planetary gearbox and the second gear reduction, so you may be able to rotate the motor a little bit without having the swerve module rotate. In the end, I'd imagine that this doesn't cause too much error.

Re: New AndyMark Products (Swerve & Steer module?)
 

Thanks, the more you know.

Re: New AndyMark Products (Swerve & Steer module?)
 

Hi CD
There is an encoder on the back of the 775 motor and there is also a mount for an absolute encoder on the main mount plate.

The robot's weight is carried by a bronze thrust washer, the lateral loads are carried by a large OD roller bearing.

Thanks
Danny

Re: New AndyMark Products (Swerve & Steer module?)
 

these look pretty sweet.

do you know when they will be available?

Re: New AndyMark Products (Swerve & Steer module?)
 

Wow, $325 for literally everything needed is a game changer. Do you have a weight? It looks pretty light.

Also, will individual components like the encoder or the U the wheel is housed in be available for sale individually?

Re: New AndyMark Products (Swerve & Steer module?)
 

The total weight of 1 modules is 8.218lbs

We are planning a having the individual parts available, stay tuned to the newsletter and website for more info about those.

Thanks
Danny

Re: New AndyMark Products (Swerve & Steer module?)
 

I noticed that too. I did some quick calculations on the bending of the shaft under stall conditions and got .000187 max deflection. But keep in mind that's at the end of the shaft, not the mating surface of the bevel gear. So it seems the long cantilever shouldn't be a problem at all.

For those interested, the values I used to calculate the deflection are as follows:
.75 length of unsupported shaft
26.5 angle of pinon pitch cone
20 degree pressure angle
3/8" 4140 hex shaft
47 lbs radial pinon load under stall
145 in-lbs at pinon under stall
25 and 50 mm pitch diameters (from AM site)

-Adrian

Re: New AndyMark Products (Swerve & Steer module?)
 

Wow, I'm confident we could build this faster than our versa-chassis. I really love how it comes fully assembled, the drive train is something I want to touch as little as possible. Being able to purchase a replacement module and just swap it in is awesome.

Re: New AndyMark Products (Swerve & Steer module?)
 

8.2lbs is a little much, but still realy good with everything on it.
Are the gears steel or aluminum? Are there alternate gear ratios available?
I'm wondering if there's a way to remove the first stge of gear reductions without compromising anything. This could easily be made half a poun dlighter if that were the case.

EDIT: I can't see in the cad how the smaller bevel gear is constrained axially. Is there a shaft collar I'm missing?
DOUBLEEDIT: Same goes for the large bevel gear. It appears to only be constrained by a single e-clip and the wheel. And the wheel is not constrained.

Re: New AndyMark Products (Swerve & Steer module?)
 

I imagine it would be incredibly difficult to get it to weight any less...

PG-71: 1.9
CIM: 2.82 lbs
4" wheel: 0.31 lbs

However you slice it, you pretty much have to have those components for swerve (we wont go into variants that chain together steering... that invites a compromise situation that I don't think these modules were designed for). Those 3 parts alone total up to 5.03 lbs, which is 61% of the weight of the module.

Of course, there's always the discussion on where to spend your weight budget, and how advanced drive trains like swerve play in... but that's probably best left to a different thread :)

This looks like a pretty awesome solution. Personally, instead of a PG-71 for steering, I would have liked to see an attempt made to incorporate the Denso Throttle Motor... we've been allowed up to 4 of them in the past, yet I think they are the most under-utilized motor in FRC so far! Of course, using them would probably require a complete gear box design as well...

Re: New AndyMark Products (Swerve & Steer module?)
 

8.2 is fine.

Its a COTS swerve for $325. Thats a different set of design constraints than a team. Very difficult.

Re: New AndyMark Products (Swerve & Steer module?)
 

I'm gonna second both of these concerns, especially the second.

Re: New AndyMark Products (Swerve & Steer module?)
 

I love the design. $325 is absolutely incredible. Even custom swerves can cost more than that (for sure), and after seeing how many machined components are in this one I'm shocked they're not selling it at a loss.
8.2lbs was okay a few years ago, but we have seen lighter swerves from all over CD in the past few months (including a shifting version similar to this weighing in at 7lbs, and that one would survive a season as it was designed by PWNAGE) with this same basic design. Combined with the extra high COG of this module, I feel like it could be improved quite a bit. If a COTS swerve drive could compete with WCD in terms of weight, then it would be a pretty big improvement IMO. Of course I love swerve drives, so I'm more than a little biased here.
I'm looking at the CAD right now to see if there are any cheap improvements that can be made to raise the caster box up a level. It looks like it's filled with custom parts already (seriously, just look at it) so some different lightening patterns could really hack off a lot of weight. Plus, there's an extra plate that doesn't need to be there under the top plate.

Re: New AndyMark Products (Swerve & Steer module?)
 

Please design something lighter that could be made and sold for the same price then.

Re: New AndyMark Products (Swerve & Steer module?)
 

Don't forget mechanical slop, harder to model.

The slip fit in the being multiplied times that length is more appreciable.

Its probably fine, AndyMark knows their stuff... but it looks scary at first glance.

Re: New AndyMark Products (Swerve & Steer module?)
 

This is going to be a blessing and a curse. I foresee many teams not prepared to do swerve doing swerve.

Re: New AndyMark Products (Swerve & Steer module?)
 

we found out the limiting factoring to swerve is not making a module, but having the programming to control all 4 at once.

Re: New AndyMark Products (Swerve & Steer module?)
 

What aspect of the programming did your team find troublesome?

Re: New AndyMark Products (Swerve & Steer module?)
 

1339 will be staying away from swerve for the time being, even though so much awesome stuff has been released this year. We just don't want to get in over our heads and build a robot we can't compete with.

Re: New AndyMark Products (Swerve & Steer module?)
 

Our team has very little programming support, and struggled with tuning a swerve. We understand that the math for it is online, and we use your math for our mecanum, but sensor integration and PID have been very difficult for us.

Re: New AndyMark Products (Swerve & Steer module?)
 

The thing is, I can't gauge the cost of making this. Please just take a look at the CAD; there are many custom parts that need to be CNC'd or even shaped.
Look at it this way: if you want something cheaper, then you can just take any old swerve drive and CNC all the parts from stock. Heck, might as well just make the encoders too, just for the lols. Sure, it's cheaper- technically. But there's no way of knowing how much their machine time is worth, and how long it would take to manufacture some of the more complex parts.

AM's design is fantastic in that it's also bulletproof, which adds to weight as a tradeoff. But I think it's possible to make it lighter without increasing the number of non-COTS parts, by using concepts laid out in (for example) Aren's recent swerve. I'll let you know if it's possible to remove that middle plate. My goal is to add one more part (made by a team or something) but decrease the weight by removing some of the other parts.

Re: New AndyMark Products (Swerve & Steer module?)
 

Pull the smaller one off the shaft, you will see it is constrained from moving up by a step in the shaft and down by the larger bevel gear. As for the larger one I am not sure, I see the e-clip in the middle of the drive shaft (somewhat concerning putting a stress riser there, I have seen 1/2 in drive shafts break due to e-clips), preventing it from moving in a direction it wouldn't want to move in due to the smaller bevel gear as for the other direction I see nothing, the wheel is floating unless the spacer is the wrong size, if it moved at all the screws would hit the side wall. http://screencloud.net/v/nEx

As Adam said, AM knows their stuff but it would be nice to know. Can't wait to see this in person, probably at the AM booth in STL if we don't use them this year :P

Re: New AndyMark Products (Swerve & Steer module?)
 

Hello, just an update on the mods I want to make on the Swerve And Steer:
I think it's possible to remove the middle plate. I'll post a pic of my plan soon, but it should involve only a single custom part- an encoder mount that holds on the front face of the cim (this can be printed). Oh, and two COTS parts that are like $20 combined.
Once I'm done, I'll post a pic of the before and after. Should shorten the module by 1.5" and shave off a ton of weight.

Re: New AndyMark Products (Swerve & Steer module?)
 

Is there a way to implement an encoder for the CIM output/wheel rotation?

Re: New AndyMark Products (Swerve & Steer module?)
 

What is the benefit of the absolute encoder? Other than the encoder, is anything else needed to interface the absolute encoder (e.g. a spur gear)?