07-11-2008 00:31

Eugene Fang

Re: pic: 6 wheel suspension

Very cool.

Just a few questions:

1- Do you have springs that try to keep the chassis straight? or is it just gravity that keeps the thing flat.

2- Since it is foldable (meaning two points on the chassis will not stay the same distance from each other), how would you attach an arm/manipulator to the chassis?

07-11-2008 00:36

Akash Rastogi

Re: pic: 6 wheel suspension

Lol,

weird thing is that I was playing around with 401's robot design tool on their website a few hours ago and thought of this idea and drew it up. Hehe

Guess my idea came out pretty good didn't it? Looks good, please do elaborate about the actual suspension system/springs. What type of load does it need to be under to actually take effect?

07-11-2008 00:54

R.C.

Re: pic: 6 wheel suspension

Man that is cool, is it springeddd on both sides or just the front???

07-11-2008 07:08

sgreco

Re: pic: 6 wheel suspension

That's very cool. I'm glad to see that you got it to work.

That would have been really cool in '06 and '07 with the ramps.

How much does it weigh?

07-11-2008 17:04

joeweber

Re: pic: 6 wheel suspension

Lots of questions. Vidio http://www.youtube.com/watch?v=urFsD0gA1D4
Its not a good vidio but it works.

More pictures and drawings of the ball diferental http://www.team1322.org/ideas.htm

I will be taking pictures of the ball differental soon for our web sit.

The picture with the aluminum plate is for demostration only. A frame would be attached to the two rods and one of the drive halves will be slotted to allow the suspension to work. I have not made the slots yet but will. The whole idea is to allow for ramp use with mecanum wheels and also give alitle more pushing in forward. The final design will have the gear boxes go right into the mecanum wheels. This means if I order everything from bain bots and anndy mark and make the side plates I can throw the whole thing together in no time. The ball differental was easy to make. The wheel took awhile to make but we had all the stuff show in our inventory.

07-11-2008 22:36

Raul

Re: pic: 6 wheel suspension

That is pretty cool.

Team 356 also did something similar in 2003 but without the Mechanums. http://www.chiefdelphi.com/media/photos/14812

Also back in 1999 team 157 had an 8-wheel articulating drive base that could climb the platform by manipulating the height of the front and rear drive wheels. Wish I could find a picture of that one.

08-11-2008 11:39

ggoldman

Re: pic: 6 wheel suspension

I am glad you got some use out of the design tool

(P.S. I made it)

The drivetrain looks great!

08-11-2008 16:51

R.C.

Re: pic: 6 wheel suspension

Is there anyway to download that???

08-11-2008 21:19

AdamHeard

Re: pic: 6 wheel suspension

Thinking about it, I think it will be impossible to accurately "tune" the ball differential.

If you put it on blocks, the load on the wheel will be substantially different than when on the floor, and if it looks like it's working, it most likely won't when you put it on the floor.

If you try to tune it on the floor, the floor will make it appear to match the speed of the outer two wheels, regardless of whether or not it actually contributes.

09-11-2008 07:28

ggoldman

Re: pic: 6 wheel suspension

Currently, the only version available is through the website. I do have the flash program still if you have a circumstance that does not let you see the website.

-Gabe

09-11-2008 10:47

joeweber

Re: pic: 6 wheel suspension

To test how tight they have to be we will prop up the mecanums up with casters and than run with just the omni wheels. This should give us a good idea on the amount of slippage under pressure.

In studying drive system that teams have used through the years I have found that the mecanum system is the best except for the following items.
1. When going up ramps you must hit it square, but with this suspension you can hit it At an angle.
2. They are not great for pushing. With the added omni wheels it will give a little help (not a lot but some is better than none). We were in a match with our standard drive system and was up against a mecanum system and every time we tried to push and block them the just went around us like we were not their.

The good of the system out weighs the bad by a large amount. We have use omni drive in the past and are familiar with it but are just learning about the mecanum system and we need to know what to look out for with problems. Please let as know.

09-11-2008 11:42

Nuttyman54

Re: pic: 6 wheel suspension

Are the two chassis sides linked (ie when one side articulates, does it carry the other with it)?

09-11-2008 13:25

joeweber

Re: pic: 6 wheel suspension

Drawings are at http://www.team1322.org/ideas.htm under "six wheel omni".

It is semi independent suspension on all wheels but the right is separate from the left. Because the frame attaches at the two point’s center of each drive half (between the omni and mecanum) the frame lifts about half of the front wheel rise. No springs are required, the weight of the robot should keep it all down. We may add springs later if needed. We are thinking that we could add pneumatic control to help with it, also use it to lift the front wheels to get up onto a step. The weight is approximately 25 lbs for each drive assembly.

10-11-2008 22:09

DarkFlame145

Re: pic: 6 wheel suspension

Very cool, not technically a suspension, but a flexing chassis (the only reason why i say that is because I work on cars all day at College). Although it is the closest thing to a suspension right now FIRST wise (from what I have seen). That idea would of be ideal for 2006 and 2007, maybe even 2009 if there is some sort of steep incline.

Like i said very cool and should come in VERY handy in the future since FIRST likes to use rams in some aspects of the games in the past.

11-11-2008 03:19

rachal

Re: pic: 6 wheel suspension

looks nice, although it might obstruct manipulator mounting. do you not need chain tensioners?

13-11-2008 18:22

joeweber

Re: pic: 6 wheel suspension

We have the sprockets and wraped the chain around them and worked out the distance. For the #35 chain it was 15in +/- 1/16. Doing this we do not need to tension the chain. Add a link than add 3/8 in, add two links add 3/4in.....

The game commin up will determin how we will attach the arms.