|
|
|
 Thank goodness there are people in this world who refuse to let physics and calculus ruin a good story. - Richard Wallace [more] |
 |
|
|||||||
|
||||||||
Discussion
view entire thread
04-04-2012 13:08
CalTran
Re: pic: Two bot side balance
It's pictures like these that make me question Newtonian physics...the one that makes me question it even more is the Robotnauts "illegal" but ingenius bridge device.
04-04-2012 13:10
Madison
Re: pic: Two bot side balance
How is this legit but 118's machine was not? There appears to be a mechanical device under that robot that straddles the bridge angle.
04-04-2012 13:38
PAR_WIG1350
Re: pic: Two bot side balance
|
Originally Posted by Madison
How is this legit but 118's machine was not? There appears to be a mechanical device under that robot that straddles the bridge angle.
|
04-04-2012 13:45
PAR_WIG1350
Re: pic: Two bot side balance
|
Originally Posted by PAR_WIG1350
It straddles the angle, but it will likely only react against one side at a time. The part on the outside of the angle appears to just act as a stabilizer since they can't balance on a row of wheels alone. They are just resting on the bridge while occupying the smallest footprint possible as a result of a cleverly placed center of gravity; making it much more like Swampthing than 118's robot, Endeavor.
|
Edit: and now VB3 gives me the option to modify my previous post, how convenient
04-04-2012 13:55
Cory
Re: pic: Two bot side balance
This is clearly illegal. Physics does not support a scenario in which that robot can remain on the bridge without applying force to both sides of the angle, unless the CG remains over the bridge surface, which is highly improbable.
Cannot believe this was allowed to compete after 118 was denied.
04-04-2012 13:57
AdamHeard
Re: pic: Two bot side balance
|
Originally Posted by Cory
This is clearly illegal. Physics does not support a scenario in which that robot can remain on the bridge without applying force to both sides of the angle, unless the CG remains over the bridge surface, which it clearly does not.
Cannot believe this was allowed to compete after 118 was denied. |
04-04-2012 14:02
Brandon Holley
Re: pic: Two bot side balance
Wow. 2 things:
1. Creative design 3534. Many teams thought of devices like this to aid in balancing either with 1 or 2 other robots, but....
2. If this device is not just a CG tweak it would be clearly illegal. 118 amongst other teams (ourselves included) would be utilizing a side hanging device that accomplishes the same effect had it not been ruled illegal before the first qualification day of the week 1 regionals.
-Brando
04-04-2012 14:04
smistthegreat
Re: pic: Two bot side balance
|
Originally Posted by Cory
This is clearly illegal. Physics does not support a scenario in which that robot can remain on the bridge without applying force to both sides of the angle, unless the CG remains over the bridge surface, which is highly improbable.
Cannot believe this was allowed to compete after 118 was denied. |
EDIT: From this image, it appears that the side over the bridge is considerably more dense than the other side, including solid aluminum (steel?) blocks being used as ballast, so the possibility of an extremely biased CoG is possible. However, it also appears that there is a metal piece under the robot touching the side of the bridge. I can't tell if it's just used for allignment or if it reacts against the bridge.
04-04-2012 14:11
AdamHeard
Re: pic: Two bot side balance
|
Originally Posted by smistthegreat
It's not probable, but it is possible that their CoG is indeed over the bridge surface. Just from looking at this picture, it seems like they have a relatively small superstructure, which could free up weight to use as ballast towards the bridge side. However, I have no idea if this is actually the case. If someone from this team or someone who is familiar with this robot could clear this up, that would be wonderful.
EDIT: From this image, it appears that the side over the bridge is considerably more dense than the other side, so the possibility of an extremely biased CoG is possible. However, it also appears that there is a metal piece under the robot touching the side of the bridge. I can't tell if it's just used for allignment or if it reacts against the bridge. |
04-04-2012 14:12
Thad House
Re: pic: Two bot side balance
|
Originally Posted by smistthegreat
It's not probable, but it is possible that their CoG is indeed over the bridge surface. Just from looking at this picture, it seems like they have a relatively small superstructure, which could free up weight to use as ballast towards the bridge side. However, I have no idea if this is actually the case. If someone from this team or someone who is familiar with this robot could clear this up, that would be wonderful.
EDIT: From this image, it appears that the side over the bridge is considerably more dense than the other side, so the possibility of an extremely biased CoG is possible. However, it also appears that there is a metal piece under the robot touching the side of the bridge. I can't tell if it's just used for allignment or if it reacts against the bridge. |
04-04-2012 14:14
pfreivald
Re: pic: Two bot side balance
If that's nothing more than a CG trick, that's just awesome.
04-04-2012 14:15
JABot67
Re: pic: Two bot side balance
What I heard and observed from being at the competition is that 3534's center of gravity is indeed over the bridge when it does its side hang.
|
Originally Posted by Cory
This is clearly illegal. Physics does not support a scenario in which that robot can remain on the bridge without applying force to both sides of the angle, unless the CG remains over the bridge surface, which is highly improbable.
Cannot believe this was allowed to compete after 118 was denied. |
04-04-2012 14:18
Nathan Streeter
Re: pic: Two bot side balance
|
Originally Posted by Cory
This is clearly illegal. Physics does not support a scenario in which that robot can remain on the bridge without applying force to both sides of the angle, unless the CG remains over the bridge surface, which is highly improbable.
Cannot believe this was allowed to compete after 118 was denied. |
I don't have that hard a time believing this one wasn't ruled illegal, though... This one looks to basically be sitting on the bridge. 118 looked to be hanging off the side. So much of how the GDC ends up ruling things is based off how the solution looks. If they see something they don't like, it seems like they then figure out how to rule it illegal... * sigh *
EDIT:
Wow, if that really is true about the robot being designed so it's CG is in the 8" on the bridge-side of the robot, that is simply incredible! Congratulations!
Even if it is illegal, I'd still say congratulations on accomplishing it - I would wish it (and 118's hanger) were legal!
04-04-2012 14:20
s_forbes
Re: pic: Two bot side balance
Given that the robot was able to drive up the bridge (I'm assuming from the other photos that it made it up under it's own power), there must be enough weight over the drive wheels for it to power itself up, in which case grappling the lip is not necessary to stay on the bridge. I highly doubt you would be able to drive a robot up the bridge if it relies on clamping force on the lip to keep it from falling off. I'm curious as to how the friction from the portion of the robot touching the lip did not inhibit it from driving up though.
Doesn't look "clearly illegal" to me.
Congrats to 3534 for creating and carrying out this design! Out of the box approaches are risky but oh so cool.
04-04-2012 14:22
JABot67
Re: pic: Two bot side balance
|
Originally Posted by Nathan Streeter
Agreed... This is fundamentally the exact same mechanism of "grasping" the sidewall as 118 used if the CG isn't over the bridge surface, like you said. The only solutions physics could allow for this Free Body Diagram (that I can think of) would involve either "gluing" yourself to the surface of the bridge or "grasping" the sidewall of the bridge similar to how 118 did.
I don't have that hard a time believing this one wasn't ruled illegal, though... This one looks to basically be sitting on the bridge. 118 looked to be hanging off the side. So much of how the GDC ends up ruling things is based off how the solution looks. If they see something they don't like, it seems like they then figure out how to rule it illegal... * sigh * |
04-04-2012 14:23
jblay
Re: pic: Two bot side balance
People need to relax a bit before coming to conclusions on this and ask questions.
Hey cptopher, can you explain how this works because it's legality might be questionable? If it is legal though that is some clever work and I commend you for pulling this off.
04-04-2012 14:23
lnader
Re: pic: Two bot side balance
I was able to see this robot in action. It is steel ballast on the edge. The parts you see under the robot are alignment guides, and do not touch the sides the the rail when it is on the bridge. I believe (not being certain) that there is a surface which rides on top of the rail.
It would be no different than if a robot got bumped off the side of the bridge and they were resting on their chassis.
The head referee checked at the end of each match to make sure there was no lateral contact on the bridge.
04-04-2012 14:28
cptopher
Re: pic: Two bot side balance
It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.
This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too.
Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts.
Chris
Team 3534 ME Mentor
04-04-2012 14:28
Tom Bottiglieri
Re: pic: Two bot side balance
Wow, cool! It's hard to tell from the photo that there is ballast on the bridge side of the robot, thanks for clearing that up.
Are you going to champs?
04-04-2012 14:29
Madison
Re: pic: Two bot side balance
|
Originally Posted by cptopher
It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.
This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too. Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts. Chris Team 3534 ME Mentor |
Do you have any pictures showing the drive train from below? I'd like to see the belt and drive shaft more closely.
04-04-2012 14:30
Nathan Streeter
Re: pic: Two bot side balance
|
Originally Posted by cptopher
It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.
This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too. Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts. |
04-04-2012 14:33
jblay
Re: pic: Two bot side balance
|
Originally Posted by cptopher
It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.
This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too. Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts. Chris Team 3534 ME Mentor |
04-04-2012 14:40
Brandon Holley
Re: pic: Two bot side balance
Wow, kudos on a very unique design! That is quite a commitment. I always enjoy seeing outside the box, yet legal, designs.
04-04-2012 14:55
RobotMom
Re: pic: Two bot side balance
I love seeing what other teams come up with each year. Very creative!
Was your team able to do a triple balance like this during competition?
04-04-2012 14:55
Joe Ross
Re: pic: Two bot side balance
Here's a description of another team that does something similar: http://www.chiefdelphi.com/forums/sh...9&postcount=11
04-04-2012 16:58
PAR_WIG1350
Re: pic: Two bot side balance
I'm glad that this worked for you; it is really cool. In 2010, My team, 1350, built a robot that functioned identically when completely inverted (it didn't have a top, just two bottoms joined at their bumper zones). It worked, but not particularly well, especially after the frame started to bend.
04-04-2012 16:59
Ken Streeter
Re: pic: Two bot side balance
WOW! Very well done! Building your entire robot with this design constraint is a remarkable accomplishment!
Very deserving of the creativity award!
04-04-2012 17:08
cptopher
Re: pic: Two bot side balance
Unfortunately we are on the bubble to get into the state championship. We probably won't get in. We performed poorly at Kettering but had a great weekend at Livonia. Our first time in eliminations and going to semi finals far surpassed our goal this season.
We are disappointed because we really wanted to pull off a 3 long bot balance in competition at Livonia. When we fell off the bridge once, it broke a belt pulley side which eventually broke our lower chain.
The bot will balance without the side guides. It rests on the belt vertically only. Its all very simple weight and balance calculations. The side guides just help to keep us on the center of the belt and lined up. They are fixed and do not move. They don't grab the sides of the rail to stabilize.
The inspiration came from a rail grind sliding move in skateboarding, or riding the pipe in snowboarding. Just needed the belt for more traction. I'll post some photos soon.
Thanks to everyone for the positive comments.
04-04-2012 17:22
jblay
Re: pic: Two bot side balance
|
Originally Posted by cptopher
We are disappointed because we really wanted to pull off a 3 long bot balance in competition at Livonia. When we fell off the bridge once, it broke a belt pulley side which eventually broke our lower chain.
|
04-04-2012 19:51
cptopher
Re: pic: Two bot side balance
|
Originally Posted by cptopher
Unfortunately we are on the bubble to get into the state championship. We probably won't get in. We performed poorly at Kettering but had a great weekend at Livonia. Our first time in eliminations and going to semi finals far surpassed our goal this season.
We are disappointed because we really wanted to pull off a 3 long bot balance in competition at Livonia. When we fell off the bridge once, it broke a belt pulley side which eventually broke our lower chain. The bot will balance without the side guides. It rests on the belt vertically only. Its all very simple weight and balance calculations. The side guides just help to keep us on the center of the belt and lined up. They are fixed and do not move. They don't grab the sides of the rail to stabilize. The inspiration came from a rail grind sliding move in skateboarding, or riding the pipe in snowboarding. Just needed the belt for more traction. I'll post some photos soon. Thanks to everyone for the positive comments. |
05-04-2012 01:04
Tom Line
Re: pic: Two bot side balance
Clearly you guys came up with an incredible design, inside the rules. Sorry I haven't gotten to see it play yet!
05-04-2012 02:45
jason701802
Re: pic: Two bot side balance
|
Originally Posted by cptopher
Can I add photos directly to my post reply?
|
where you can put an external link to the photo. Unfortunately, you have to start a new thread to directly upload photos.
05-04-2012 09:32
kramarczyk
Re: pic: Two bot side balance
Here is a shot of the optical illusion that is a triple long robot balance on the practice field at Livonia. All three robots are completely supported by the bridge. It took about 45 sec for the drivers to do it the first time and they got it down to about 35 sec in the 5 min practice time we were allowed with the bridge.
05-04-2012 09:38
dman9385
Re: pic: Two bot side balance
I find this thread pretty funny when you read it all the way through. Right off the start everyone is crying foul, illegal, i can't believe they allowed that ect. Then you have it explained how it works and that the ref looked at it every match to make sure nothing was touching the bridge lip. After that everyone chimes in again oh great job, well planned, amazing, ect. This is indeed one well designed robot and maybe others need to look at the pictures more closely and ask questions to how it works before claiming them to be illegal. 
view entire thread
Tags
loading ...