Let's Talk About The Bridge:

[BrendanB]

@davidthefat

Personally, I want to take all the human aspects out of the balancing. The operators are facing them head on, not to the side of the board. So my plan is to get all the alliance members up and tell them to drop all controls so the software can do its work.

Three robots operating on software to balance on a ramp in which they barely fit? Could work but you need all three to do that which will be extremely rare! It is almost like having a robot in 2010 that could hang off the tower and have two to hang off of it for bonus points. It only happened once all season and with two robots not all three.

[Ninja_Bait]

@BrendanB

The only way you are fitting three is with 3 robots that are at least 28 inches wide and you’ll have 11 inches of overhang at best.

Dear Everyone:

Please build a little robot like Team Thrust’s in 2010, so we will all fit on our ramp during the match.

Thanks
694

[davidthefat]

@KrazyCarl92

What about placing an accelerometer on the robot that allows it to autonomously balance on the bridge? You could have it detect when you are unbalanced on the bridge then press a button that activates the auto-balance and drives to correct the imbalance. Just tell whomever you are balancing with that you have this auto-balancing feature and you have yourself 20 points or 10 points and a 2 point CP bonus as the case may be!

I was just thinking of going for 2 PID loops. One to actuate the platform to the right position and the second to find where to move the platform to. Personally, a gyroscope would be better. Since it gives us the angular velocity, I just integrate that over time and you get the net angle of the gyro.

edit: any legality on “latching” onto other robots? The “t-rex” arms to push the platform down can be used to latch onto robots.

[Ninja_Bait]

@davidthefat

edit: any legality on “latching” onto other robots? The “t-rex” arms to push the platform down can be used to latch onto robots.

Interesting question. G27 prevents you from doing it on the coopertition bridge:

Deliberate or damaging contact with an opponent Robot inside its Frame Perimeter is not allowed.

But not with your own alliance partners. Hmmm…

[Kevin_S]

@akoscielski3

I am wondering how robots are going to make the bridge go down form the neutral position. That may be hard. Is it just gonna be you run into it and it will move? or will we have to make a mechanism to lower it for us? Any thoughts?

At our local kickoff we had a prebuilt one to play with, if there is no weight on it to make it offbalance it will automaticly rebalance itself. This means that you will probibly have to buld somthing to keep it down as your robot is getting on. They are also fairly high off the ground, so you cant just run into it unless you are trying to push it down for an aliance member on the other side.

[pfreivald]

I’m thinking “robot one moves onto the ramp, robot two moves onto the edge. Robot one stops moving, robot two balances with accelerometer or gyro assist.”

If three robots, it becomes, “robot one moves onto the ramp, robot two moves onto the edge. Robots one and two creep forward until robot three can move onto the AAAAAAAAAAAAAAAAAAAAAGH! THIS IS SO HARD!”

Should be awesome!

[davidthefat]

How much force is required to bring the ramp down?

[BrendanB]

@davidthefat

How much force is required to bring the ramp down?

None of us could tell. Can’t bring it down with your finger but put your foot on it and with a little pressure it came down. No exact measurements.

[davidthefat]

@BrendanB

None of us could tell. Can’t bring it down with your finger but put your foot on it and with a little pressure it came down. No exact measurements.

So I’ll have to keep torque in mind. Really heavy weight is needed to tilt it from the middle area of the bridge.

[nighterfighter]

@BrendanB

None of us could tell. Can’t bring it down with your finger but put your foot on it and with a little pressure it came down. No exact measurements.

On the video on Youtube they stated that if you place 2 batteries next to each other, 28 inches out, the bridge should stay level. Move it an additional 2 inches I believe, and it would tilt.

Use physics, convert and stuff, and there’s your answer!

[Mongai]

@davidthefat

My guess is, like most years, the majority of the robots will be around 120 lb and it would be relatively easy to balance one or two on the bridge.

Ah, but remember that robot weight isn’t evenly distributed.

[KrazyCarl92]

What about this scenario:

Eliminations, you have two robots on your alliance bridge and one robot on the coopertition bridge (and thus prevent your opponent from scoring on the coopertition birdge):
You get 20 points for the 2 robots on the alliance bridge and 10 points for the robot on the coopertition bridge, meanwhile preventing your opponent from scoring 10 points because you prevent them from using the coopertition bridge.

Unless your opponent could get 3 robots on their bridge, this scenario would come out the same as if you got 3 robots on a bridge and they got one robot on the coopertition bridge in terms of point differential.

I think the bridge will prove to be pivotal because not only do I think the points are weighted more balanced than in past years (…minibots), but also because FIRST reserves the right to change the point values come Championships.

[Ninja_Bait]

The Coopertition bridge scores no match points.

G40:

When the final score is assessed per [G37], a Balanced Alliance Bridge, per Section 2.2.5, earn points

(note that the coopertition bridge is excluded from this rule)

And G41:

If a Robot from each Alliance is balanced on the Coopertition Bridge when the final score for a Qualification Match is assessed per Rule [G37], each Alliance earns 2 Coopertition Points.

(note that the coopertition bridge scores only coopertition points in this rule)

[davidthefat]

So in other words, go big or go home.

[Marc_S]

If you made a wide base robot you could have a larger intake and more easily fit 3 bots on a ramp.

[Peyton_Yeung]

I think getting 3 bots on will work well if the last bot to get on has a bridge lowering device.

[Djur]

@davidthefat

How much force is required to bring the ramp down?

It’s ~10 lbs at an end of the bridge. (estimation)

@KrazyCarl92

What about placing an accelerometer on the robot that allows it to autonomously balance on the bridge? You could have it detect when you are unbalanced on the bridge then press a button that activates the auto-balance and drives to correct the imbalance. Just tell whomever you are balancing with that you have this auto-balancing feature and you have yourself 20 points or 10 points and a 2 point CP bonus as the case may be!

That’s actually ridiculously easy; I coded that from scratch on the 1hr drive back from the kickoff.

[Andrew_Y]

just put your battery on a linear slider and rack and pinion…::safety::

[jreuter]

[G37] Final scores will be assessed 5 seconds after the Arena timer hits zero.

So, whatever you do to balance, make sure it stays in position after you lose power.

[pfreivald]

@Marc S.

If you made a wide base robot you could have a larger intake and more easily fit 3 bots on a ramp.

An omnidrive robot can more easily fit, too.