Bumpers vs Frame which is better [Archive]

Alex Cormier

27-02-2006, 15:32

I was watching the Rochester Rally II a few days before ship and i remember 1511 ramming into 211 and 1511 just bounced off. 211 was the one who had the bumpers, i don't remember seeing two robots hitting that each had bumpers. But i was totally impressed on how well those work.

Alan Anderson

27-02-2006, 15:36

A robot using bumpers has a fifteen-pound advantage over a robot not using bumpers. I find it difficult to imagine lighter being better in an otherwise matched contest.

Koko Ed

27-02-2006, 15:37

ebmonon36

27-02-2006, 15:39

The bumpers will definately help protect the robots against hard hits especially during autonomous with all 6 robots starting reletively close to each other. I don't see them as benefitting one side more than the other. As noted by other posters, the extra weight might help. You're still going to see pushing matches and some ramming. The bumpers will help the robots stand up to the beatings better.
Eric

JJG13

27-02-2006, 15:40

Also, bumpers add 15 pounds of legal weight. More weight should mean more traction which means a better pushing robot. Though, I'll miss the sound of crashing metal on metal :D .

Dan Petrovic

27-02-2006, 15:48

Also, bumpers add 15 pounds of legal weight. More weight should mean more traction which means a better pushing robot. Though, I'll miss the sound of crashing metal on metal :D .

That's a reason to keep bumpers off of your robot :)

sanddrag

27-02-2006, 16:11

I see bumpers as a failure point. If they rip or fall off or something, they can get caught in your drive system.

Alex Cormier

27-02-2006, 16:17

I see bumpers as a failure point. If they rip or fall off or something, they can get caught in your drive system.
that's why you securely fasten them. you have at least a 1lb or so for fasteners of the bumpers, use it!

Kevin Ray

27-02-2006, 16:28

Ahhhh, I'll rely on the other team's foresight, caution and proactive nature to allow our metal frame to bounce off their bumpers while we use a more sleek conformation to maneuver about the field (and ramp) unencumbered

Eldarion

27-02-2006, 16:54

The way I look at this is if we find the bumpers to be a problem, FIRST did require us to make them easily removable... ;)

Jay H 237

27-02-2006, 17:11

Even though the bumpers may add 15# to a robot the additional weight alone may not be an advantage. You also have to take into account how well the wheels grip and how strong the drive system is.

I also see the bumpers lessening the shock the electronics would take in a collision with another robot or field element.
(pun intended ;) )

Starke

27-02-2006, 17:55

#340 was going to use bumpers. then we realized that our design would not allow for the bumpers. having the bumpers where FIRST wants them to be would not allow us to make it up the ramp or be able to collect the amount of balls that we wanted to.

i agree that bumpers give you and advantage with having an extra 15 pounds. i guess well have to see what the regionals will show for the bumpers.

Schneidie

27-02-2006, 17:59

I wanted to know what everyone thought will be better. If bumper will turn the tide helping the offense or will a robot with no bumpers rule the defensive field

A bot with bumpers will probably be better, as I have noticed that if your robot is broken, you can't qualify for the finals of a regional.

Faith

27-02-2006, 18:34

I think bumpers are better in most cases. They do add an extra 15lbs of weight. They also make it harder to injure your robot, which is always a plus. In some cases they may prevent climbing the ramp, however - they may also help climbing the ramp, making the robot less top-heavy. It all depends on the robot...

I guess defense it would be better to have bumpers for protection, weight, and traction.

KenWittlief

27-02-2006, 19:12

I dont remember off the top of my head, do the bumpers have to fit within the footprint size limit of the robot, or do they extend past that?

for stability you want your wheels as far apart as possible. If you must make your frame smaller to leave room for the bumpers, then you have traded off robot stance (stability) for impact protection.

BTW - impact is a fascinating field of study. Metal hitting metal can experience thousands of g's, even at low speeds (10mph, like our robots).

Zoheb N

27-02-2006, 19:16

i say the bumbers r better.. because they allow for a low CG and protect valuable parts of your robot.. although we didn't use a bumber because of all the specs to them.. we just reinforced our frame and moved all of our controls towards the inside for safety

Cody Carey

27-02-2006, 19:32

Who needs 'em when everyone else has 'em, HUh? ;)

blue_crew

27-02-2006, 20:27

With the continuous pushing and shoving, robots are going to take a punishing and bumpers are going to help immensely.

What are you all finding as the best way to attach the bumpers to your frames so they are easily removable? Particularly those of you who attached them to the Kitbot frame.

Faith

27-02-2006, 20:32

I think we are just using screws...

Ted Boucher

27-02-2006, 20:49

So I am going to look at this whole thing from another perspective...

One of the reasons I liked having the bumpers this year was the amount of weight we could lose from the robot. Since our outside drive side panels are now covered and not exposed to a robot directly hitting them, we were about to swiss cheese them a little bit more than we would of.

New ways to remove weight safely are the best.

KenWittlief

27-02-2006, 21:17

Who needs 'em when everyone else has 'em, HUh? ;)

what good are bumpers on other robots when you slam the wall or railing?!

Aaron D.

27-02-2006, 21:23

The way I see it is that there is no negative from having bumpers!

Kevin Ray

27-02-2006, 21:41

Ken,
You're right, we inadvertently SLAMMED into a cement wall at full speed (12fps) three times during auto programming. We were lucky and had no ill effects. But bumpers would have been nice though.
Another added advantage for some teams is that the 15 or so lbs. are on the BOTTOM of the bot and add to stability. I just watched the videos of the UTC matches and it makes you realize just how top heavy many bots are this year.

http://media.putfile.com/Team-329-ball-pickup

Nita

27-02-2006, 22:16

The bumpers will not only help keep the robot safer, it adds more weight to the bottom of the robot, which will help keep it from tipping. Besides, it's more space for team colors!

bk111

28-02-2006, 15:05

Bumpers in all cases except when you have a spring-supported frame or a geometrically sound frame. I haven't heard anything about using springs to reinforce a frame, though. Would it be legal?

Mike Norton

01-03-2006, 06:58

Bumper do a few things for the robot. It will protect things you want protected. Like for us it is the sides. We left the front and back open to be able to push others around. but if we want to block someone we would use the sides of the robot. Weight is big ( more traction ). low CG is also better. Your robot gets to start bigger.

If bumpers are done right it should give the team a better robot.

the_short1

01-03-2006, 10:12

hmm, I wonder why our team didnt think of bumpers... one on the front would help, due to the position of the electronics this year is rather close to the front for comfort :(

theirs pros and cons......its all physics, inelastic vs elastic collisions.. . ohhh.. im not going to be able to watch a match without thinking physics (go gr12 physics:))

pakrat

01-03-2006, 10:54

While we were practicing a night or two before ship, Don Wright asked us if we were using bumpers. We said we weren't sure, and he went on to explain that he noticed that robot tended to ride up on balls. Not always, and I know FIRST said in Section 5 that the bumpers were designed not to ride up on balls, but we still dont' feel to safe about riding up on those things, especially because our drivetrain is quite needy as far as having all wheels oin the ground all the time. I don't think we'll use bumpers, but if we decide to, we always have thursday at GLR to build some..

Peter Matteson

01-03-2006, 11:51

The Lucas

01-03-2006, 13:37

One negative I heard about from the scrimmage is that robots no-longer glance right off each other but can stick because of bumper friction. That means a more sudden stop when hit than without bumpers. Hope your internal components can take the loading.

How can it be a “more sudden stop” when the duration of the collision is longer with the same force? This means less impulse and less sudden stops. However, it may mean more frequent stops as the bots stick together instead of just glancing off.

The added friction is a good point. It may be easier to pin robots this year as the added friction makes escape harder. You may be able to pin a bumper robot sideways against a wall. From a dead stop, a robot may not be able to overcome the static friction of 2 fully compressed nylon bumpers in order to slide out of a sideways pin.

Just think of a rubber stopper or a cork in a bottle. This could factor into corner goal defense.

Theory6RobotiX

03-03-2006, 15:57

Question to teams who have competed in the first weekend regionals.
Watching the webcast from the VCU regional, I feel that most but not all teams have bumpers on their robot. Despite the "strong encouragement for having bumpers" from FIRST and the obvious advantages (weight for pushing, protection) what do you think is the reason for teams actually going through matches without bumpers?

Andrew Blair

03-03-2006, 19:19

How can it be a “more sudden stop” when the duration of the collision is longer with the same force? .

Well, I guess, it's not a more sudden stop when you compare a direct collision, but in the case of an indirect hit, where metal on metal would allow more of a glance, resulting in less energy transfer, the bumpers would stick on eachother, causing most of the collision impulse to be transfered. Metal on metal causes a greater impulse, but evidently to a lesser magnitude in some cases.

Dominicano0519

03-03-2006, 22:46

Please what is worth more points a blocking robot, or one that can get up on that platform for 15 points. at the jersey regionals i have seen atleast 12 robots bounce off of the platform because of their bumpers

If you ask me a good strong chasis should do u good

And it would sound cool too

StephLee

04-03-2006, 08:50

Please what is worth more points a blocking robot, or one that can get up on that platform for 15 points.

What if your robot blocks the third robot on the opposing alliance from getting up the ramp at the end, thereby dropping their bonus from 25 points to 10? That might not be worth points to YOUR alliance, but it shifts the margins, and such a big shift could be enough to swing the match.

It's a matter of trade-offs. You can win both by scoring points and by keeping your opponent from scoring points.

We used bumpers, and we're still fine getting up the ramp. Depends on your design, and your strategy.

mrmummert

05-03-2006, 00:37

here is my input on the bumpers from first hand observation....
the bumpers not only (because of the design)have been protecting the frame,covers,wheels,drive and electronics...but also have been an advantage
to help the robot from tipping over if they have been applied to best use.

The tipping issue is most useful on robots with short wheel bases (mostly on four wheel bots)

I think after last years game because of the damage that could be done,
this might be why they suggested the bumpers

Rick TYler

05-03-2006, 00:58

We practiced without bumpers, but added them for competition. They probably saved us any number of problems, including one match in which we nearly tipped over, but the bumper provided just enough width to allow us to rock back. We have a pretty low CG (it's one of the few really good things about our bot), but we tipped once in practice and nearly did (thank you, bumper) once in quals. Successful robots competed without them, but a lot of good bots used them.

The smart ticket would have been to use them as a stressed frame element, but we've already gone over that elsewhere...

Kyle Love

05-03-2006, 01:22

On the webcast I only noticed teams benefitting from bumpers. I saw some of them stay upright due mostly inpart to their bumpers. Sure, it will make it a bit harder to get up the ramp, but move the bumper up on the frame by a 1/2-3/4 inch and you will be good. (I would guess) Plus, they help keep your frame a little bit more beautiful for the pit and off-season demos. :rolleyes:

Steve Kaneb

05-03-2006, 02:30

Team 190 chose not to use bumpers, and this turned out to be very advantageous. At the BAE regional, we were consistently able to maneuver around robots and through holes in defensive fronts. During our defensive period, we were often blocking 2 robots, and often kept these periods scoreless. This would not have been possible with bumpers because we relied on short, sharp shocks to robots to get them out of alignment. Despite the 15 pounds of stability advantage that bumpers afford, we never tipped and were frequently pushing bumpered robots around with ease.

Aside from that, we were thankful for not having bumpers because we often needed to check our chains on the driveline, our wheels and our spacers to make sure that it was all in order. Not having bumpers was also really helpful in the pits, because there wasn't extra room, and we keep most of our systems at bumper level.

Important items pertaining to our disuse of bumpers:
Almost all of our weight is wheel level. We're about 2-4 lbs. underweight, with a 6-wheel, one speed driveline.

Matching up against and with robots using bumpers, we noticed that there was a lot of trouble with the ramp and with defense. While the bumpers protected against collision effects, they got in the way of blocking, and often forced robots into misalignment.

Wayne C.

05-03-2006, 06:16

I see bumpers as a failure point. If they rip or fall off or something, they can get caught in your drive system.

The real failure point is where your frame gets mangled and the battery and wiring going with it gets caught in your drive train.....

Pro Bumpers- of course I can relate to anything that adds an extra 15 lbs of padding around the middle....

WC :cool:

Bharat Nain

05-03-2006, 07:38

I don't know which is better because you have to determine what works best for you. What I can say is that bumpers are more fun in a defensive match. They are great shock absorbers.

Dan Petrovic

05-03-2006, 11:50

After the BAE Regional, I saw the Bumbers are far better than no bumpers. Reason being is that the bumpers increase your footprint so it saves you from tipping. We fell over a few times without bumpers and when we did they saved us from countless tips. They also prevent running over balls. Those balls are a pain when you start driving over them and around them.

Rick TYler

05-03-2006, 11:59

Pro Bumpers- of course I can relate to anything that adds an extra 15 lbs of padding around the middle...

Bumpers are the nachos with extra cheese of FIRST.

Andrew Y.

05-03-2006, 13:43

this years game can put some massive beatings on the robot!. we our whole entire frame warrped after a few rounds. This is when bumpers are good.

Only problem with them are when 2 bumpers are put together, they cause alot of friction making it harder to get out of pinned situations.

Peter Matteson

06-03-2006, 08:36

Well, I guess, it's not a more sudden stop when you compare a direct collision, but in the case of an indirect hit, where metal on metal would allow more of a glance, resulting in less energy transfer, the bumpers would stick on eachother, causing most of the collision impulse to be transfered. Metal on metal causes a greater impulse, but evidently to a lesser magnitude in some cases.

That's what I was getting at. With the metal on metal/lexan the robots not only slid off each other they could spin each other better so that all the momentum transfer was not just in one direction. The lessen the impact along any given vector.

A couple other things:
If you attached your bumpers correctly they will not effect maintanence.

Bumpers will help the CG of most bots not hurt it based on what I've seen. Most have way to high a CG anyway.

evelyn1503

06-03-2006, 09:05

well in my opinion if you use bumpers then you don't have to worry that mutch about your ralis being bent in

hansTP2S

06-03-2006, 10:04

???????

looneylin

06-03-2006, 10:57

bumpers definitely for all the reasons already listed

the bumper on the back of our robot says "bump this!" :D

114gopher

07-03-2006, 00:50

Our team is currently regretting our lack of bumpers. In the second match of the final round, we fell over, and got hit repeatedly. This was the straw that broke the camel's back, so to speak, as we had been taking a beating all the time (because of our fantastic shooter). Two welds broke, our main 120amp breaker broke, and our electronics box is now skewed. We had to hold the back part of our frame together with zip ties for the final match :D . It was funny, but we now regret the no bumpers decision.