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Unread 04-15-2018, 12:14 PM
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Swerve drive introduction

Our team is looking at doing an offseason swerve drive project this summer to serve as an introduction to the concept. We're thinking about just coughing up for the AndyMark swerve modules in order to maximize the time our programming team gets, as well as to minimize initial frustration. Does anybody have insight into these modules? Are they worth it? Or does anybody have a suggestion for a relatively easy to manufacture swerve design? We have CNCs, 3D printers, and a plasma cutter, but our time that we will actually have in the shop this summer will be somewhat limited.
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Unread 04-15-2018, 12:25 PM
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Re: Swerve drive introduction

Quote:
Originally Posted by npbartelt View Post
Our team is looking at doing an offseason swerve drive project this summer to serve as an introduction to the concept. We're thinking about just coughing up for the AndyMark swerve modules in order to maximize the time our programming team gets, as well as to minimize initial frustration. Does anybody have insight into these modules? Are they worth it? Or does anybody have a suggestion for a relatively easy to manufacture swerve design? We have CNCs, 3D printers, and a plasma cutter, but our time that we will actually have in the shop this summer will be somewhat limited.
What main build system do you use (e.g. Versaframe, sheet metal, AM)?
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Unread 04-15-2018, 12:43 PM
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Re: Swerve drive introduction

From what I have heard the andymark modules tend to wear pretty fast, but with some modifications can be made to work reliably. If you are only using them to program and don't plan on using them in competition they can be a good place to start.

In terms of design of your own modules, definitely avoid things like slip wrings and CVT/two speed as they significantly over complicate things. I have posted the full cad of the modules we (apple pi) used in the past and I would consider them to be relatively simple when compared to other swerve designs, but they are still very complex. The CAD posted before build season for this year was still a prototype, I will be posting the final version in the coming weeks.

It is also worth looking into 1640s non-cvt modules as well as the documentation they have on their site, it is very extensive and they are excellent at swerve.
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Unread 04-15-2018, 01:31 PM
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Re: Swerve drive introduction

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Originally Posted by C4 View Post
What main build system do you use (e.g. Versaframe, sheet metal, AM)?
We'll probably use 2x1 tubing that's either welded or riveted together, similar to versaframe.
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Unread 04-15-2018, 05:20 PM
wgorgen wgorgen is offline
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Re: Swerve drive introduction

I'm biased, but I think our swerve modules are pretty simple.

https://www.chiefdelphi.com/forums/s...hreadid=164790

All the parts are either COTS or flat pattern that you could easily cut with your plasma cutter (we use waterjet to cut our parts). The only tricky part is machining the groove for the ball bearings, but this can be done very easily on your CNC (we cut the groove on a simple mill using a rotary table).

I know we posted the CAD for version 4.0 last year. Version 4.1 is a relatively small change to switch to Colson wheels for better tread life. I will check with my son and see if he posted the CAD for that version.

https://www.chiefdelphi.com/forums/s...d.php?t=152393

Link to version 4.0 CAD files:

https://grabcad.com/library/strange-swerve-4-0-1

As far as coding, our code was also posted last year. The code is very straight forward. You need to adjust the length and width of the robot and that is about it. The vector math takes over from there.

Link to code:

https://github.com/ecgrobotics/Strange-Swerve

If you have the means to cut the custom parts, I would recommend trying this design. It has gone through a lot of refinement and is very solid now.
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Unread 04-15-2018, 05:32 PM
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Re: Swerve drive introduction

Quote:
Originally Posted by npbartelt View Post
We'll probably use 2x1 tubing that's either welded or riveted together, similar to versaframe.
If you're using 2x1, I'd definitely look at 1533's 4.1 modules. Those are really solid and work really well with versaframe-esque stuff.
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Unread 04-15-2018, 06:38 PM
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Re: Swerve drive introduction

Quote:
Originally Posted by OwenD View Post
From what I have heard the andymark modules tend to wear pretty fast, but with some modifications can be made to work reliably. If you are only using them to program and don't plan on using them in competition they can be a good place to start.

In terms of design of your own modules, definitely avoid things like slip wrings and CVT/two speed as they significantly over complicate things. I have posted the full cad of the modules we (apple pi) used in the past and I would consider them to be relatively simple when compared to other swerve designs, but they are still very complex. The CAD posted before build season for this year was still a prototype, I will be posting the final version in the coming weeks.

It is also worth looking into 1640s non-cvt modules as well as the documentation they have on their site, it is very extensive and they are excellent at swerve.
Thanks for the advice! I'll be on the lookout for your CAD.
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Unread 04-15-2018, 06:40 PM
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Re: Swerve drive introduction

Quote:
Originally Posted by wgorgen View Post
I'm biased, but I think our swerve modules are pretty simple.

All the parts are either COTS or flat pattern that you could easily cut with your plasma cutter (we use waterjet to cut our parts). The only tricky part is machining the groove for the ball bearings, but this can be done very easily on your CNC (we cut the groove on a simple mill using a rotary table).
Thanks! That looks pretty doable. Is there a BOM anywhere with the estimated price?
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Unread 04-16-2018, 09:51 AM
tdogb tdogb is offline
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Re: Swerve drive introduction

Quote:
Originally Posted by wgorgen View Post
I'm biased, but I think our swerve modules are pretty simple.

https://www.chiefdelphi.com/forums/s...hreadid=164790

All the parts are either COTS or flat pattern that you could easily cut with your plasma cutter (we use waterjet to cut our parts). The only tricky part is machining the groove for the ball bearings, but this can be done very easily on your CNC (we cut the groove on a simple mill using a rotary table).

I know we posted the CAD for version 4.0 last year. Version 4.1 is a relatively small change to switch to Colson wheels for better tread life. I will check with my son and see if he posted the CAD for that version.

https://www.chiefdelphi.com/forums/s...d.php?t=152393

Link to version 4.0 CAD files:

https://grabcad.com/library/strange-swerve-4-0-1

As far as coding, our code was also posted last year. The code is very straight forward. You need to adjust the length and width of the robot and that is about it. The vector math takes over from there.

Link to code:

https://github.com/ecgrobotics/Strange-Swerve

If you have the means to cut the custom parts, I would recommend trying this design. It has gone through a lot of refinement and is very solid now.
How did you guys get that large gear for steering? Did you edm it?
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Unread 04-16-2018, 11:50 AM
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Re: Swerve drive introduction

Quote:
Originally Posted by tdogb View Post
How did you guys get that large gear for steering? Did you edm it?
We used waterjet last year and tried laser this year, and both work fine. The quality isn't quite what you get out of a professionally made gear, but we've never been concerned about that because it's in a low-speed, low-load application.
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Unread 04-16-2018, 12:06 PM
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Re: Swerve drive introduction

Quote:
Originally Posted by npbartelt View Post
Our team is looking at doing an offseason swerve drive project this summer to serve as an introduction to the concept. We're thinking about just coughing up for the AndyMark swerve modules in order to maximize the time our programming team gets, as well as to minimize initial frustration. Does anybody have insight into these modules? Are they worth it? Or does anybody have a suggestion for a relatively easy to manufacture swerve design? We have CNCs, 3D printers, and a plasma cutter, but our time that we will actually have in the shop this summer will be somewhat limited.
2410 has used the Andymark Swerve & Steer Modules for the past two years. (2017 & 2018) They're mechanically sound, but they are decently heavy. (our drivetrain was around 60lbs iirc) As with swerve, there's encoders. They're a pain to get to work, but when they work, they work great. The cost of the modules is a bit steep, but I'd go with them and get comfortable with swerve before venturing to design and manufacture your own modules.
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