30-07-2012 11:09

sdcantrell56

Re: pic: My Rendition of Emperor Swerve

Pretty nutty design using all those motors but other than that it looks like a beauitful detailed model. Would be interesting to see some more details like the pods. The frame looks potentially very flexy which might or might not be an issue

30-07-2012 11:44

Ether

Re: pic: My Rendition of Emperor Swerve

Quote:

Originally Posted by Joyride_67_1902

30-07-2012 11:45

Andrew Remmers

Re: pic: My Rendition of Emperor Swerve

There are some tiny details that are missing, And I wanted to do something different, something that wasn't for competition use, but easily could be converted to something that would compete. So the 550 Gearbox can be taken off and a new belt put in place and it would power the drive train at an FRC legal drive.

Pod renders should be posted later tonight hopefully.

- Andrew

30-07-2012 11:49

Andrew Remmers

Re: pic: My Rendition of Emperor Swerve

Quote:

Originally Posted by Ether What are you using for wheel speed and steering angle sensors?

30-07-2012 12:05

Ether

Re: pic: My Rendition of Emperor Swerve

Quote:

Originally Posted by Joyride_67_1902 Encoders are on the underside of the pod, along with the shifting mechanisms and all motors.

30-07-2012 12:06

Andrew Remmers

Re: pic: My Rendition of Emperor Swerve

Quote:

Originally Posted by Ether Did you have specific part numbers in mind for the wheel speed sensors, and the steering angle sensors?

30-07-2012 15:48

Andrew Remmers

Re: pic: My Rendition of Emperor Swerve

Render Album attached, I didn't want to Spam CD media.


https://plus.google.com/u/0/photos/1...50412732351601

Enjoy

-Andrew

30-07-2012 15:57

AdamHeard

Re: pic: My Rendition of Emperor Swerve

There is a lot to talk about on this, I like the thoroughness in your design.

Probably the largest thing to comment on is the steering setup; Although I am an engineering student, it was pretty simple analysis to show that relatively small bearings (regular roller ones at that) which are very inexpensive are more than robust for the steering setup. If you have an engineering mentor with a mechanical background (or for a rougher analysis, anyone who has done statics or could do a halfway decent Free Body Diagram) they could thoroughly show this concept to you. OR, you could just take my word on it.

We initially looked into large bearing rings and similar setups, and they're just a lot of parts/complexity for all the ways we had tried to implement it.

30-07-2012 18:06

steelerborn

Re: pic: My Rendition of Emperor Swerve

I would have to disagree with Adam.

Using larger bearing for the steering in the wheels is not very complex.
Adam's math may be right and you may be able to get away with regular bearings just fine (973 used swerve this year and if they used them it probably is). But I would say that it is not complex at all to design a swerve using larger bearings. There are several ways to decrease the amount of components it takes in the design.

I would say the dynamic load of thrust bearings is a lot greater, than normal bearings, and I usually fall on the side of it is better safe than sorry, which is why I prefer the larger OD thrust bearings. McMaster-carr sells them for a good price, and even have some neutral file formats available for CAD purposes.

30-07-2012 18:56

Andrew Remmers

Re: pic: My Rendition of Emperor Swerve

Well what I did for bearings of the steering is a large AL disk that would go inside of a delrin bearing machined for the profile of the AL disk. I've seen people do this before with great success. At least I think I have. The pod first started with one bearing on the top and then once I realized the side load would be bad on it I added the bottom circular bearing as well.

-Andrew

30-07-2012 19:50

Garret

Re: pic: My Rendition of Emperor Swerve

I agree with Adam that using a combination of regular roller bearings would be far simpler for this. If you want a cheap thrust bearing we use the $4 Lazy Susan style turntables (6031K31) from mcmaster. We use these in tandem with needle bearings that handle the radial loads.

30-07-2012 21:42

AdamHeard

Re: pic: My Rendition of Emperor Swerve

Quote:

Originally Posted by steelerborn I would have to disagree with Adam. Using larger bearing for the steering in the wheels is not very complex. Adam's math may be right and you may be able to get away with regular bearings just fine (973 used swerve this year and if they used them it probably is). But I would say that it is not complex at all to design a swerve using larger bearings. There are several ways to decrease the amount of components it takes in the design. I would say the dynamic load of thrust bearings is a lot greater, than normal bearings, and I usually fall on the side of it is better safe than sorry, which is why I prefer the larger OD thrust bearings. McMaster-carr sells them for a good price, and even have some neutral file formats available for CAD purposes.

30-07-2012 22:49

steelerborn

Re: pic: My Rendition of Emperor Swerve

I knew that your math was correct 973 has used the design successfully (and quite fun to watch IMHO).

When you said "standard" FRC I thought that was the normal size, the larger size makes a lot more sense.

However, I still disagree that doing so can make things less complex it all comes down to your ability as a designer, what I find simple others can view as complex.