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 I have learned so much from this program and am forever changed by FIRST and its community. You have made me a better person in so many ways. Thank you. - Jessica Boucher [more] |
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We built a ramp using HDPE plastic and ran the robot up and down to test the suspension and six wheel drive system. It worked great.
To view a video goto http://www.youtube.com/watch?v=xby0SOphLUg&feature=channel_page
(I do not know vBCode sorry)
Discussion
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02-01-2009 11:08
Tottanka
Re: pic: Ramp Video
WOW!
Very nice guys! Congratulations on that amazing drive!
02-01-2009 15:30
joeweber
Re: pic: Ramp Video
Heres a quick link to the video
http://www.youtube.com/watch?v=xby0S...e=channel_page
I should have had it go sidways more to show that the ball differnetal works but if you look close at the start it goes sideways.
02-01-2009 16:03
Cyberphil
Re: pic: Ramp Video
Awesome! In the video, you could have made the plastic a little more sturdy. But it still made it up, amazingly easy. Great job!
02-01-2009 16:07
AndyB
Re: pic: Ramp Video
It is SO cool. I really hope to see this on your competition bot. Should be interesting to see how you end up mounting a manipulator on it.
02-01-2009 16:14
seanl
Re: pic: Ramp Video
are those chains i see going to the omni wheel in the middle? if so have you had a problem with them falling off?
02-01-2009 16:16
Tom I
Re: pic: Ramp Video
I remember admiring the design for this... good to see it came out so well!
14-01-2010 19:27
FlyingHedgeHog
Re: pic: Ramp Video
Uh... Section 8, R11 The FRAME PERIMETER must be comprised of fixed, non-articulated structural elements of the ROBOT. The FRAME PERIMETER must remain a fixed, unchanging polygon throughout the MATCH.
http://usfirst.org/uploadedFiles/Com...Robot_RevA.pdf
Sorry guys, we had the same idea...
14-01-2010 19:31
Chris is me
Re: pic: Ramp Video
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Originally Posted by FlyingHedgeHog
Uh... Section 8, R11 The FRAME PERIMETER must be comprised of fixed, non-articulated structural elements of the ROBOT. The FRAME PERIMETER must remain a fixed, unchanging polygon throughout the MATCH.
http://usfirst.org/uploadedFiles/Com...Robot_RevA.pdf Sorry guys, we had the same idea... |
14-01-2010 19:34
maltz1881
Re: pic: Ramp Video
That isn't the frame of our robot though.. so we are perfectly safe.:
Our frame won't have a suspension.
14-01-2010 20:06
FlyingHedgeHog
Re: pic: Ramp Video
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Originally Posted by maltz1881
That isn't the frame of our robot though.. so we are perfectly safe.:
Our frame won't have a suspension. |
14-01-2010 20:08
FlyingHedgeHog
Re: pic: Ramp Video
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Originally Posted by FlyingHedgeHog
FRAME PERIMETER – the polygon defined by the outer-most set of exterior vertices on the ROBOT (without the BUMPERS attached) that are within the BUMPER ZONE. To determine the FRAME PERIMETER, wrap a piece of string around the ROBOT at the level of the BUMPER ZONE - the string describes this polygon.
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14-01-2010 20:50
Nuttyman54
Re: pic: Ramp Video
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Originally Posted by FlyingHedgeHog
I think the judges would frown on that, it's kind of lawyer-ing, you know? I mean, the point of that Rule R11 is to prevent you from doing that. I don't think you should do it, as much as I would LOVE to...
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...not that it wouldn't be pretty awesome to see in competition...
14-01-2010 22:09
DonRotolo
Re: pic: Ramp Video
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Originally Posted by Nuttyman54
This picture was posted a year ago
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15-01-2010 07:33
joeweber
Re: pic: Ramp Video
As you can see from the drawing the frame is stationary on level ground and does not articulate. When it goes over the ramp the drive system articulates but the frame remains solid. ( the frame is where the bumpers are attached).
15-01-2010 08:30
GaryVoshol
Re: pic: Ramp Video
Joe, it seems to me that as the middle wheel goes up, the outer wheels go down. Wouldn't this cause the bumper height to change? Bumpers must remain in the BUMPER ZONE, 10-16" off a level surface.
15-01-2010 08:34
Rosiebotboss
Re: pic: Ramp Video
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Originally Posted by GaryVoshol
Joe, it seems to me that as the middle wheel goes up, the outer wheels go down. Wouldn't this cause the bumper height to change? Bumpers must remain in the BUMPER ZONE, 10-16" off a level surface.
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15-01-2010 11:06
betsy888
Re: pic: Ramp Video
Looks like your center wheels are 2 individual omni wheels per side, each one slaved to either the fore or aft mecanum wheel. So basically the center wheels are commanded to have the same velocity profile as the front/back wheels. Is this accurate? 
btw, awesome design and thanks for sharing your ideas. We're a second year team so still need lots of help!
15-01-2010 11:16
Chris is me
Re: pic: Ramp Video
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Originally Posted by betsy888
Looks like your center wheels are 2 individual omni wheels per side, each one slaved to either the fore or aft mecanum wheel. So basically the center wheels are commanded to have the same velocity profile as the front/back wheels. Is this accurate?
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15-01-2010 16:46
FlyingHedgeHog
Re: pic: Ramp Video
This may sound a tad bit pompous but that seems like lawyering to me. The way we look at it is: What's the purpose of the rule? What is it trying to stop us from doing?
Last year, there was a robot that had fans on the bottom of it at the Portland regional. The idea was to suck it down to the floor in order to gain more traction. The judges didn't let it slide and the team ended up with a box on wheels. I'm not trying to be a rules Nazi, I just think the judges won't let it pass and you'll be in some serious trouble...
15-01-2010 16:53
Chris is me
Re: pic: Ramp Video
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Originally Posted by FlyingHedgeHog
This may sound a tad bit pompous but that seems like lawyering to me. The way we look at it is: What's the purpose of the rule? What is it trying to stop us from doing?
Last year, there was a robot that had fans on the bottom of it at the Portland regional. The idea was to suck it down to the floor in order to gain more traction. The judges didn't let it slide and the team ended up with a box on wheels. I'm not trying to be a rules Nazi, I just think the judges won't let it pass and you'll be in some serious trouble... |
The Q&A is the only way to figure out answers to designs like this.
15-01-2010 17:56
Brad Voracek
Re: pic: Ramp Video
You also have to watch out for your max height.
Don't make the robot 5 feet above the frame, make it 5 feet above the wheel at the lowest point.
How they would test this in the box.. I don't know.
But still, ask the Q&A if you guys go with it. Awesome drive.
17-01-2010 21:49
joeweber
Re: pic: Ramp Video
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Originally Posted by GaryVoshol
Joe, it seems to me that as the middle wheel goes up, the outer wheels go down. Wouldn't this cause the bumper height to change? Bumpers must remain in the BUMPER ZONE, 10-16" off a level surface.
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The measurement is taken when the robot is on flat floor. We meet all requirements that we have found in the rules. The bumpers are between 10 an 16 inches above the floor when on flat ground.
17-01-2010 22:26
Gdeaver
Re: pic: Ramp Video
If I was an inspector, I would measure your robots bumpers with all wheels in contact with the floor . Then I would ask you to full articulate the wheels and then measure the bumpers. If at both configurations the bumpers where with in the bumper zone then I would be satisfied. If not then I would turn this down. I am not an inspector nor am I a member of the GDC. You better Q & A this soon before you go farther. From the picture your bumper height appears to be variable and not fixed or static.
17-01-2010 22:35
JB987
Re: pic: Ramp Video
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Originally Posted by Gdeaver
If I was an inspector, I would measure your robots bumpers with all wheels in contact with the floor . Then I would ask you to full articulate the wheels and then measure the bumpers. If at both configurations the bumpers where with in the bumper zone then I would be satisfied. If not then I would turn this down. I am not an inspector nor am I a member of the GDC. You better Q & A this soon before you go farther. From the picture your bumper height appears to be variable and not fixed or static.
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17-01-2010 23:26
BJT
Re: pic: Ramp Video
Everyones bumpers will be out of the bumper zone when going over a bump, so if this thing is legal on the floor it seems fine to me.
18-01-2010 08:01
Gdeaver
Re: pic: Ramp Video
If the robot is flat on the floor and the middle wheel is articulated up, are the bumpers still in the bumper zone? This really needs a Q&A. Also with the bumpers up high this year, robot frames will be subjected to allot more stress than in past years with the low riders. Make sure those supports are robust.
18-01-2010 10:50
joeweber
Re: pic: Ramp Video
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Originally Posted by Gdeaver
If the robot is flat on the floor and the middle wheel is articulated up, are the bumpers still in the bumper zone? This really needs a Q&A. Also with the bumpers up high this year, robot frames will be subjected to allot more stress than in past years with the low riders. Make sure those supports are robust.
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18-01-2010 12:03
maltz1881
Re: pic: Ramp Video
The center Omni's are ALWAYS touching the ground, they never leave the floor. They aren't powered by anything other than the friction on the carpet when the Mec wheels are moving. The bumpers are in a permanet position. If you use the bump to manuvere around the field then no matter what your bumpers are going to change height. Meaning when you are going up your back bumper will be closer to the ground then if you were on level ground and just the opposite when going down the other side. The bumpers are solid and in the correct height while on LEVEL ground!
We have read the rules many many times and the question has been given to Q & A. We have asked many many teams in our area about it and if this is doable. Most agree with us that it is perfectly fine while others weren't sure. We are 99.9% sure that we are correct and would be shocked to see anything differently.
19-01-2010 22:13
JesseK
Re: pic: Ramp Video
Yep Joe, Update #3 today also green-lighted it. I really look forward to seeing this design in action! Be sure to post some videos of it during competition.
20-01-2010 09:32
betsy888
Re: pic: Ramp Video
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Originally Posted by Chris is me
There's a ball differential so if the front and back wheels are spinning in opposite directions, the omnis don't turn.
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Thanks again! Good luck with your design. Congrats on getting the green light in Q&A!!
20-01-2010 09:47
joeweber
Re: pic: Ramp Video
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Originally Posted by betsy888
How does your ball-differential work? From what I understand of ball differentials, there is one drive gear and 2 driven axles. So I assume your center omni wheels are on the driven axles. But you have 2 driving chains coming from the omni wheels and only one drive gear. Do you have a special type of ball differential? Can you explain a bit more?
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The Mechanum wheels are driven, the chains drive sprokets on the ball differential, between the sprockets are steel balls that are inside a round flange with holes for the balls. The flange is attached to the drive shaft with the omni wheels. Pictures are on our wesite http://www.team1322.org/ideas.htm
20-01-2010 09:57
the man
Re: pic: Ramp Video
Is that the 45degree angle of the ramp? it looked to shalow, and you should build a real bump if possible because it is much harder to test with out the real thing if you know what i mean.
20-01-2010 10:08
joeweber
Re: pic: Ramp Video
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Originally Posted by the man
Is that the 45degree angle of the ramp? it looked to shalow, and you should build a real bump if possible because it is much harder to test with out the real thing if you know what i mean.
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The video ramp is a 45 degree ramp but we had to cut the corners for the low ground clearence of the 6 inch wheels. We will be using 8 inch
20-01-2010 11:07
DynamiteHack
Re: pic: Ramp Video
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Originally Posted by joeweber
As you can see from the drawing the frame is stationary on level ground and does not articulate. When it goes over the ramp the drive system articulates but the frame remains solid. ( the frame is where the bumpers are attached).
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Unless the mountings can tilt in and out?
20-01-2010 11:39
joeweber
Re: pic: Ramp Video
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Originally Posted by DynamiteHack
Correct me if I'm wrong, but wouldn't the sections connecting the omnis to the mountings have to get longer/shorter as it tilted? Adding height to the slope gives a longer line.
Unless the mountings can tilt in and out? |
20-01-2010 21:44
betsy888
Re: pic: Ramp Video
[quote=joeweber;902964]The Mechanum wheels are driven, the chains drive sprokets on the ball differential, between the sprockets are steel balls that are inside a round flange with holes for the balls. The flange is attached to the drive shaft with the omni wheels. Pictures are on our wesite http://www.team1322.org/ideas.htm
I think I know the source of my confustion. I assumed the omni wheels could move independent of each other. Now that I see your ball differential drawing and photos it looks like they are attached to the same shaft so must move together. If this is true, why do you have 2 omni wheels at each location, why not just one?
As always, thanks and good luck!
20-01-2010 21:51
EricH
Re: pic: Ramp Video
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Originally Posted by betsy888
If this is true, why do you have 2 omni wheels at each location, why not just one?
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