Chief Delphi

Chief Delphi (http://www.chiefdelphi.com/forums/index.php)
-   Extra Discussion (http://www.chiefdelphi.com/forums/forumdisplay.php?f=68)
-   -   pic: Swerve Shifter (http://www.chiefdelphi.com/forums/showthread.php?t=117054)

pranav1014 23-05-2013 20:09

pic: Swerve Shifter
 

Andrew Remmers 23-05-2013 20:10

Re: pic: Swerve Shifter
 
This looks like a good start! I didn't even think about shrinking my Swerve design by adding the ballshifter!

DampRobot 23-05-2013 20:28

Re: pic: Swerve Shifter
 
Is that drive chain exact c-c? If it isn't, you're going to need to look into tensioning...

Mk.32 23-05-2013 21:10

Re: pic: Swerve Shifter
 
Quote:

Originally Posted by DampRobot (Post 1276915)
Is that drive chain exact c-c? If it isn't, you're going to need to look into tensioning...

Or some GT2 5mm timing belt with C-C ;)

Boe 23-05-2013 22:52

Re: pic: Swerve Shifter
 
the only thing that concerns me is the module itself doesn't look like it will survive missing two of four sides, butt you may have suppressed them to show the innerds. Either way looks great love the ball shifting to narrow down the gear box.

Adrian Clark 24-05-2013 02:51

Re: pic: Swerve Shifter
 
Is the whole weight of the robot supported by that one bearing? TBH that's absolutely terrifying. I would't be surprised if the jerky movements of the bot make that bearing pop right out.

How is your turning pulley mounted to the module? In this render it appears to be mounted to the drive shaft, but that can't be right.

What's holding your miter gears and sprocket in place? What keeps the gears from sliding on their shafts, and what keeps the top gear from sliding down?

How do you plan on making the turning module frame? Is a solid piece of metal or do you plan on making it in multiple parts?

Anyway, great job on getting the whole shifting gearset to be single stage!

-Adrian

CENTURION 24-05-2013 06:18

Re: pic: Swerve Shifter
 
Looks pretty darn good!

Personally, I would move the module rotation belt and stuff inside the housing, rather than hanging below like it is. That will allow you to put a thrust bearing between the module and the lower plate of the housing, which is pretty essential if this is going to actually support a robot.

I'd suggest taking a look at 1640's swerve designs. Their design is very effective on the field, and they have been good enough to release basically everything you could ever want to know about it online, including CAD models.

I'm not saying "Scrap your design, go with theirs" but a lot of the challenge of swerve drive is finding the issues that you can't forsee in CAD, and fixing them. And they've already done that part for you ;)

apalrd 24-05-2013 10:05

Re: pic: Swerve Shifter
 
Few comments:

-You need a sensor location for both the steering and drive. An absolute encoder is preferred for steering, team 1640 has excellent information on such sensors. It looks like you retained the US Digital drive gear from the ball shifter.

-You need a lot more support for the entire module. Specifically:
--Thrust surface on top
--Something to react module torque on the pivot - either a needle bearing on top, large bushing surface, or a delrin ring around the bottom which reacts to a chassis member.
--The drive axle should react no force except the torque it is driving

-The drive chain is fine exact c-c, you will have no problems with a chain of that length and sprockets of that size.

pranav1014 24-05-2013 11:12

Re: pic: Swerve Shifter
 
Quote:

Originally Posted by Adrian Clark (Post 1276979)
Is the whole weight of the robot supported by that one bearing? TBH that's absolutely terrifying. I would't be surprised if the jerky movements of the bot make that bearing pop right out.

As of now it is, I realize that should be changed and will find some way to do so.
Quote:

Originally Posted by Adrian Clark (Post 1276979)
How is your turning pulley mounted to the module? In this render it appears to be mounted to the drive shaft, but that can't be right.

There are three holes drilled into the pulley and the module. It will be bolted together so they both move.
Quote:

Originally Posted by Adrian Clark (Post 1276979)
What's holding your miter gears and sprocket in place? What keeps the gears from sliding on their shafts, and what keeps the top gear from sliding down?

This was one of the problems I faced originally. My best guess is super gluing the key shaft, but I really do need to find a better solution.
Quote:

Originally Posted by Adrian Clark (Post 1276979)
How do you plan on making the turning module frame? Is a solid piece of metal or do you plan on making it in multiple parts?

Sadly, I do not have the resources to make this, but if it were to be made I would either use one solid piece or make multiple parts and try welding it together.

Clem1640 24-05-2013 16:43

Re: pic: Swerve Shifter
 
I like the use of the ball shifter in this application, but I've got some questions

It looks as if your drive shaft (3/8" of 1/2") is your pivot axle and is taking all of the axial, radial and shear loads. I would expect this shaft to fail in use.

What bears the weight of the robot (the axial load)?

How is the rotating pivot cage secured to the vertical drive axle? This will be a high-load joint, but I don't see how this is done in the drawing.

A clever approach.


All times are GMT -5. The time now is 12:02.

Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi