Re: Self-righting
 

to solve our problem with tipping, #340 has designed a wheelie bar that comes down when needed to keep the robot down while going up the ramp. it weighs all together including the pneumatics 4 pounds.

Re: Self-righting
 

well that wouldn't work for us but maybe we could use a light weight wheelie bar just have it pulled in slightly or something

Re: Self-righting
 

Unless you're gunning for the ramp, I don't think you seriously need to be worried about tipping. Our robot last year was unable to right itself, and it extended up to 13 feet in the air. We got hit with our robot holding tetras at least 9-10 feet in the air, and the only time we ever tipped was because another robot's arm became entangled with ours and pulled us down.

Without high extensions or wedged robots this year, tipping is one of my least worries. Those teams that took advantage of the bumpers will be in even better shape with an extra 10-15 lbs. on the bottom of their robot.

Our team hasn't experienced any problems with getting poof balls caught underneath us, but that will be an individual issue depending on what your robot's ground clearance is. Poof balls under a robot "bouncing it" onto its side would be the only way I see teams getting tipped UNLESS they go for the ramp.

Re: Self-righting
 

Quick explanation for beth's comment, as i was the one ignoring her screams:
i was able to tip our robot so that the highest most point was about 1ft from the ground
as we stand now our robot is only 68 pounds (we will be adding more) but of those 68 pounds, 65 of them are within 9 inches of the ground because the rest is just a hopper. we also plan on adding an extra 50 to the chasis at the competition, as well as battery and bumpers. So in the end, we should have about 140/145 pounds within 1ft from the ground spread out through the entire chasis
needless to say, with such a low CoG, we shouldnt have any tipping issues with our bot

Re: Self-righting
 

Our robot had a small problem of tipping coming off the ramp due to a higher-than-wished CG. We solved the problem by writing a ramp unmount procedure and by adding several pounds to the front (we were underweight by like 9 pounds.)

Re: Self-righting
 

We currently don't have anything to prevent tipping on this years bot but we may add something at our first regional if we find out we need it.

On last year's bot we had what we called Wheelie Stilts, very simple and light weight, and no powered parts. All you need is some Aluminum Angle, String, and two bolts in the size of you choice.
Our the bottom half of our robot last year was basically a box (as many bots are this year)
What we did was:
1. Cut a piece of Aluminum Angle (to size you need), and cut about 1" of one of the legs (right or left side depending on the side you are working on) off (so you have for example 19" of true 90 degree angle and 1" of flat stock.)
2. Line up the angle so it sits around the existing frame and the 1" flat spot is up and on the side of your robot the spot you choose should be strong enough to support the weight of your robot and drill a hole in the side of your frame and another on the flat part of the Al angle.
3. Put a bolt through both holes (line the with a washer in between them put a nut on and tighten it (leave it lose enough so the angle can pivot).
4. Test lean your robot back (simulate a flip) and the angle should swing out. Now find how far it must swing our to stop the robot from falling and right itself again.
5. Measure and cut a piece of string to stop it at that point and drill two more holes to tie the string to. Tie the string off and test lean it again to make sure. Adjust as necessary.

It does work last year at West Michigan we had our arm out and up trying to cap a corner goal, someone pushed us from behind and we fell forward against the goal. After they backed off we swung back up so fast we tipped backward and the Wheelie Stilts stopped us from falling over backward.

Pic This picture isn't very good but its the best view of the stilts that we uploaded last year. The pivot point is right in the middle of the 8 you can see the string on the other side.

Hope this helps

Re: Self-righting
 

I saw one of the scrimmage videos. In it, one team has these plates the folded agianst the robot ball container, but would open up so the balls would be able to bounce in(i'm assuming), anyway if they wer etipped over, it seems like they would be able to right themselves.

Re: Self-righting
 

self righting technology? thats old stuff!

Re: Self-righting
 

We were joking around one day about how we could just tip ourselves onto the ramp if we wanted the points at the end of the match, since we were so top heavy. Now that i think about it it wouldn't have been a bad idea, easier than raising our chassis to go up the stupid thing.

Re: Self-righting
 

probably a very stupid idea but if you put a pneumatic cylinder on each side if the robot tipped over you could use the pneumatic to self right the bot.

i just thought of this because I remember the self righting robots on robot wars and they used pneumatics to right themselves

Re: Self-righting
 

I think everyone gets it


no one
can save
themselves

Re: Self-righting
 

Easy! Drive slower, and switch the jumpers on the victors powering your drive motors to coast! The coast setting really does work, because when our driver decides to stop short ( which he usually does), the robot slows down instead of coming to a jolting stop and then flip over. Though I don't think the coast setting works in reverse! :ahh:

Re: Self-righting
 

There are pros and cons to being tall. Although you are top heavy, if your shooter is up on top(60 inches) you cannot be blocked. It all depends on the strategy.

Re: Self-righting
 

You can also try acceleration and deceleration functions in the coding. That works for both directions if done right.

Re: Self-righting
 

You have officially jinxed us all :o :(