Robots Tipping Over

[scottmacdonald]

I was wondering if anybody has seen any robotics tip over during the competitions this year?
It seems less likely because of the trailer.

I remember is happening a couple times last year when tall robots would ram into the overpass. Or in 2006 when they had to climb the ramp at the end of the match.

Thanks

[Nick Lawrence]

I know that at GTR we nearly tipped 1547's trailer over during a match, but as far as robots go, I have not seen a single one tip.

[nahstobor]

We have been close and have gotten under trailers but Tipping a robot over is a task to be done in the offseason (Hint, requires more than one robot).

My team honestly tried in Autonomous going full speed into a robot going full speed but we unfortunately missed and went full speed into the airlock (even getting some paint on our robot)

[AdamHeard]

My team honestly tried in Autonomous going full speed into a robot going full speed but we unfortunately missed and went full speed into the airlock (even getting some paint on our robot)

Wait, so you were trying to tip someone?

[DustinWyke]

973 got extremely close to tipping over at a few of the regionals and our trailer got over half way up onto the wall during one of the matches at champs but we never tipped completely.

[trigger]

842 almost tipped someone over if it wasn't for the trailer the other bot would have fallen over

[sammyjalex]

During qualification matches, team 341's turret completely fell over causing us a penalty for exceeding the bumper limits haha

[AlexD744]

I think 359's trailer could have been tipped at Champs after a ball got stuck under it. However, there was only 25 seconds or so left after the ball was stuck and it was never rammed. With the surface giving so little traction the wheels just slide when hit, and it would probably require something getting under teh robots and a simultaneous hit of 2 or 3 robot on one against a wall, and that 1 would have to have a very high center of gravity. So all in al it's very difficult and probably never happened.

[Nawaid Ladak]

as far as i've seen. Not a single robot has gotten tipped all of this year

for those of us who remember, Tipping five years ago was almost an every match occurance. I honestly miss robots tipping over, those were the days...

[Rick TYler]

for those of us who remember, Tipping five years ago was almost an every match occurance. I honestly miss robots tipping over, those were the days...

Start an FTC team. The small chassis sizes combined with high-friction wheels and tons of torque motors results in robots that go down more often than submarines with screen doors. On the other hand, a really large number of them this year were self-righting. 575 must have flipped over backwards an average of three times per match, and was not unusual. The faster the robot, the more likely they were to go over. With 575 it was accelerate too hard, flip over, whack bucket over the top while accelerating hard and the robot was back up and running.

[Imadapocalypse]

im not entirely sure about robots tipping on the field, but during that long walk to the playing field our robot cart almost tipped over cracks in the trail... While our robot was still on it >.<

[Akash Rastogi]

as far as i've seen. Not a single robot has gotten tipped all of this year

for those of us who remember, Tipping five years ago was almost an every match occurance. I honestly miss robots tipping over, those were the days...

You mean fun stuff like this?

Us and our rookie tipped over...fun.
http://www.chiefdelphi.com/media/img/b35/b35093e2c04987078ebce38daf43e7c2_l.jpg

[Nawaid Ladak]

You mean fun stuff like this?

Us and our rookie tipped over...fun.
http://www.chiefdelphi.com/media/img/b35/b35093e2c04987078ebce38daf43e7c2_l.jpg

it was fun having to strategize for CoG.... not to mention there were no bumpers and wedges were legal back in those days.... It was great doing the tipping, and sort of kind of exciting when you did get tipped (if it was only a couple of times per regional)

[MrForbes]

lotsa robots fell over in 2006, our rookie year, including ours on many occasions, so we learned all about CG, and haven't had one come anywhere near falling over since.

[David Brinza]

After experiencing the distinct displeasure of having their robot tip over during the 2006 GTR semifinals, Team 4 revealed their redesigned "tip-proof" robot (http://www.youtube.com/watch?v=upk5Mp6jTFA) in Atlanta.

After seeing this demo, Team 980 does all it can to maintain a low c.g. in our robots.

BTW, I've also seen stickers on the underside of robots stating: "If you can read this, please help me up.";)

[EricH]

for those of us who remember, Tipping five years ago was almost an every match occurance. I honestly miss robots tipping over, those were the days...
I don't really. A high C.G. cost my team a shot at the finals. Having a little interaction involving another robot and the step didn't help...

Yeah, we had a high CG and a wheelie bar, and still went over at least 4-5 times. One was a fall off the bar. One was a run-in with the border. Two were caused by robot interaction (and one of those, we were about to get up, but the robot came back, tipped us onto our side, and shoved us into a ball corral).

The fun part was the next year. We had wedges on our sides and a flat traction-reducing plate on the back. The one time we tipped was high entanglement, and we went over backwards. The fall freed us, and the next thing you know, we're stacking away.

Yet it's a bit more exciting when a robot is about to go down and doesn't, or goes down and gets back up...

And back on topic, I don't remember a single robot tipping this year.

[Al Skierkiewicz]

I saw a few teams teeter on Saturday. One got hung up on another robot but was stopped by the driver's station. Eventually the two robots were able to separate. Another robot jumped and got fully up on a trailer. Luckily both sides of the front were hung and the robot didn't go over. Unfortunately, all the wheels were off the ground the and the robot didn't move the rest of the match.

[Andrew Schreiber]

Yet it's a bit more exciting when a robot is about to go down and doesn't, or goes down and gets back up...

And back on topic, I don't remember a single robot tipping this year.

Agreed, I remember in 2005 2 cases where tipping was an interesting occurrence for us. First was when we got knocked over and actually bounced off our arm and came right back up (it was designed to be able to right us should we tip) The other was when 33 brought their arm down on top of a tetra we were holding by accident (they were on our alliance) Instead of losing the tetra 33 was pulled sideways and onto the ground. It showed how good a grip we had on the tetra.

And no, I saw a lot of hard hits but no tipping. As opposed to last year, I saw lots of robots on 2 wheels going around corners and several on no wheels after a failed hurdle.

One last thing, plenty of robots put funny stickers on the bottom explaining that if you can see this something bad happened. On a related note, in 2004 RUSH had a sticker about if you can read this we are hanging.

[Dan Petrovic]

166 is proud to say that they haven't tipped since week 1 in 2006. After the regional, we made modifications to lower our center of gravity and havn't tipped since.

Our 2007 and 2008 robots featured mecanum wheels and an extremely heavy drive chassis (70-80 pounds) so neither of those ever tipped.

A total of seven official competitions and even more off-season events without tipping.

I made a point somewhere here about how teams shouldn't put so much effort into making a light chassis. Put more effort into making your manipulator light.

[MrForbes]

I made a point somewhere here about how teams shouldn't put so much effort into making a light chassis. Put more effort into making your manipulator light.

I make that point over and over again.

[nahstobor]

Wait, so you were trying to tip someone?

With the bumper rules this year, the trailer strapped to your back and the inability to extend out the bumper zone it's impossible to tip a robot this year. But I guess someone had to try to get a yellow card, has anyone seen a yellow card or red card this year either, I forgot those existed.

Rookie teams next year will have some adjusting to do when they get back on carpet, no more full speed rams and full match pins or will there??

[dlavery]

Rookie teams next year will have some adjusting to do when they get back on carpet, no more full speed rams and full match pins or will there??

We are going back on carpet? :eek:





.

[Herodotus]

Please no one get Dave started. We don't want him hinting about non-hint hints all summer.

[nahstobor]

We are going back on carpet? :eek:





.

That's no problem, I like the regolith.

[MrForbes]

dave was probably thinking "jello" not regolith

[XaulZan11]

That's no problem, I like the regolith.

We are going back to regolith? :eek:

[nahstobor]

Well technically we were on carpet, except someone accidentally put their old shower wall on top of it after renovation.

[Nawaid Ladak]

I think C.G.'s Importan to learn about when building a robot, some of the newer teams might not comprehend or understand the subject matter, unfortunitly, the way the games are played these days, some of these teams will never learn. (some of these teams don't have engineering mentors...)

In 2004. Team 1402 had a robot that was stright up to the line, 5 feet tall, we learned very quickly about C.G. at our preship event. we had five practice matches, we tipped over 3 times in those five matches. We stopped, did our research and redid our frame down to 3 feet tall. a total redesizn later, we had a rookie robot that did not tip, but DID the tipping. (we learned too late that King of the Hill was the stratedgy for the game in 2004.)

our 2005 Robot (http://www.chiefdelphi.com/media/img/8ff/8ff71adfe1993a4aa468558966781888_l.jpg) was built using creativity, but the FIRST question we asked was how we could keep the C.G. low enough where we would be able to cap 4 tetra's at a time without tipping over... (we had to take into consideration the weight of four tetra's).

Because of our team's error in 2004 with our origional design, we never tipped over for the next two years

2006 and Bumpers were totally differen stories...

It's not the fact that i like to see robots tip over, it's just the fact that because robots tip over, either teams adopt to the issue, or learn something the hard way. and improve upon it.

[Cory]

I make that point over and over again.

I never understand this school of thought. It's somehow a good thing to make a drive base unnecessarily heavy, to the point where one only has 30-40 lbs for a scoring mechanism?

If you can optimize the weight of your drive base, you should. This does not mean you should have a 50 lb base and the remaining 70 lbs 4' off the floor...that's just not smart engineering. What it does mean is that when your scoring mechanism weighs 60 lbs you aren't thinking "Oh ****, how many 1" holes through 0.125" aluminum does it take to remove 20 lbs of weight?", because your robot is 10 lbs underweight. Or it allows you to add more functionality.

2007 is a prime example. How many teams made robots that had top tier scoring capability as well as double 12" ramps? If you made your base as light as possible, you could do both, and do them well. If your base weighed 2/3 of the allotted total, you'd be lucky to do either well.

In short, it seems like poor engineering to me to say that instead of more carefully controlling center of mass due to proper design, we'll just throw 2/3 of the weight onto the base to make sure we don't tip over.

[MrForbes]

Of course we don't design the base to be unnecessarily heavy, but we don't go to extra trouble to make it light...we don't bother with making fancy cutouts, or using aluminum shafts and gears in transmissions, or even using #25 chain. We do design the drive base so it is rugged and as light as it can be while requiring as little work and special stuff as possible, and easy to build quickly, so we can get the robot moving asap.

We do go to extra effort to make the stuff "up top" light, usually by designing a mechanism that has most of the weight down low.

I've never understood putting all that effort into making the drive base as light as possible, when the effort would be more effective if applied to the mechanism. If that means rethinking the mechanism design to make it simpler but still effective, all the better.

In 2007 we had a pretty heavy chassis, with an arm that was capable of hanging 6 rings, and ramp for a single robot. Being only our second year, we didn't do it all quite right, but the robot was pretty much untippable.

[Cory]

I've never understood putting all that effort into making the drive base as light as possible, when the effort would be more effective if applied to the mechanism. If that means rethinking the mechanism design to make it simpler but still effective, all the better.

I don't see why a team wouldn't do both.

I can't speak for anyone but 254, but every year it's our goal to make all systems as light as possible without expending what we judge to be an unreasonable amount of effort, or sacrificing functionality/robustness.

At best this nets us more weight for added functionality, or wiggle room for when we get to the events and decide there's something we really want to add to the robot (Or allows us to slap 10-20 lbs of dead weight onto the base of the robot). At worst it means we don't go overweight.

It's a no brainer for us. Any weight we save from the base is weight we can use somewhere else. Just because it's no longer in the base does not mean it will negatively effect our center of mass. Smart design dictates no matter how heavy or light your robot is, you don't put the weight up high.

[FRC4ME]

Start an FTC team. The small chassis sizes combined with high-friction wheels and tons of torque motors results in robots that go down more often than submarines with screen doors. On the other hand, a really large number of them this year were self-righting. 575 must have flipped over backwards an average of three times per match, and was not unusual. The faster the robot, the more likely they were to go over. With 575 it was accelerate too hard, flip over, whack bucket over the top while accelerating hard and the robot was back up and running.

I believe 339 (FTC) tipped almost every match at the Championship. One of which included smoke as a bonus.

[sdcantrell56]

After subscribing to the train of thought of building the drivebase without any real regard to weight for a couple years, and each year worrying about overall robot weight, I am now a firm believer in saving as much weight as possible every where that is possible including the drivetrain. Any weight saved means adding a new device or function or improving on another. At the bare minimum it means adding weights in exactly the right spots to maintain the best center of gravity. This year the weight savings extended to the point of using extremely fancy and rare plywood in our drivetrain. Next year and this offseason, we are looking into experimenting with timing belt instead of #25 chain as well for even more savings.

In short, every system should be as weight-reduced as is reasonably possible.

[Eugene Fang]

If you can optimize the weight of your drive base, you should. This does not mean you should have a 50 lb base and the remaining 70 lbs 4' off the floor...that's just not smart engineering. What it does mean is that when your scoring mechanism weighs 60 lbs you aren't thinking "Oh ****, how many 1" holes through 0.125" aluminum does it take to remove 20 lbs of weight?", because your robot is 10 lbs underweight. Or it allows you to add more functionality.

Last year, we had weight issues, as we were a couple of pounds overweight and eventually passed inspection at 119.8 pounds.

We kept that in mind this year, and designed everything, from the chassis to the scoring mechanism, as lightly but as robust as possible. We ended up at about 105 pounds at ship.

This allowed us to add more functionality, adding fans, encoders for traction control, and even another gearbox to slow down our shooter slightly. Eventually, we were still under 120 lbs, and we ended up strapping rebar to the bottom of our chassis.

[Rick TYler]

We are going back to regolith? :eek:

You can't fool me, young man. It's corn all the way down.

[MrForbes]

I don't see why a team wouldn't do both.

Lack of resources, mainly. It's tough out there. Given the choice between having a nicely engineered and fabricated lightweight chassis/drivetrain vs. a light manipulator, I'll take the manipulator.

I know we're not the only team that can't have both.

[Eugene Fang]

Lack of resources, mainly. It's tough out there. Given the choice between having a nicely engineered and fabricated lightweight chassis/drivetrain vs. a light manipulator, I'll take the manipulator.

I know we're not the only team that can't have both.

Just wondering, what do you consider "light?"

This year our entire drive train (chassis+wheels+transmissions+motors+chain) ended up at just over 30 pounds, and we didn't do anything special such as 7075 aluminum axles/gears or any machining for lightning holes. We even had a couple of solid aluminum blocks for modularity purposes, so if we had welded it, we could have dropped the weight about 3-4 pounds.

We usually aim for under 45 pounds drive train + electronics board, maybe a bit more if we have pneumatics.

[engunneer]

Bumper stacking seemed to be more common than tipping, but still rare. It did happen to us in Galileo in QF3_1 TBA video (http://www.thebluealliance.net/tbatv/match/2009gal_qf3m1)

we didn't move the whole match.

I do recommend looking at the other videos, it's much more interesting than us not moving :ahh:

[MrForbes]

We do pretty much the same thing, I think this year our bare chassis ended up right around 22 lbs, with the supports for the lower mechanisms in place (those 2x4s added a couple pounds). I don't consider this "light", but I also don't consider it to be "unnecessarily heavy", even though it could be lightened considerably if needed. We did a bit of work to lighten the upper stuff instead, and the final robot weight was 119.

I'm all for good lightweight robust design, with efficient material use, etc. I just don't see any need for lightweight wheels, lighweight transmissions, small chain or drive belts, or going to the trouble to cut lightening holes in the chassis, when the effort could be applied to the rest of the robot, with the result that the CG is lower and the mechanism performs better.