Does your robot have brakes? If so, how well do they work? How did you design them and how did you implement them?
Our robot has these things that run around the field that when you smash into the robot stops. They are called walls.
I mean something that is on your robot that makes you less suceptible to pushing. I have heard that 25 has them, and i’m sure other teams do as well. So, I was just asking for some details.
That is correct. We have pins that go into the cheese holes in the gears. This is controlled using a servo. Feel free to ask if you have anymore questions.
I poked around raiderrobotix.org trying to get some more information on y’all’s brakes, but I couldn’t seem to find any.
Without tipping your hand completely (what’s the sport in that?), can you give us some photos for inspiration? MS Paint drawings? ASCII art?
Are you talking about brakes to stop your wheels from turning, or a brake like a pad of brecoflex or something to come down so the robot is sitting on it make you hard to move?
Next time you are over here at AVL, let’s talk. I have some ideas for you.
Team 229 has brakes,
They are drop down pads front and back that we lower when we get in a good shooting position, or when we are loading up. They originally started out with floor mat material on them (the stuff you put under office chairs on carpet), Then we tried them with Sorbethane (the stuff Beatty used in 2003), and now they have wedgetop on them. We found that all worked better in pushing matches than just our wheels.
I will search for pictures if you’re still interested.
see our pits in Newton at Nationals and we will have a sample to show you.
As Bharat said- we use a servo to drive a pin into the gears of the drive linkage and lock up the whole gear box. The result is 130 lbs of dead weight with 6 wheel traction. You move that you deserve to win.
the idea is simple- but you need to do a little programming to go with it and the work needs to be precise. It is EASY to have the pins tear apart your whole drive train if you dont design properly. And we discovered that when they reset the FIRST fields for a blown match we need to completely reset our auto modes or they engage automatically leaving us sitting there (3 rounds at NJ!!) Servos- gotta love em!
Team 842 has some. http://www.chiefdelphi.com/media/photos/22689
571 has brakes similar to these. They are about 1.5" square of the rubber belt treads attached to a piece of wood on the bottom of a pneumatic cylinder. We have them between our omni’s (reverse shopping-cart drive) and they worked really well for us.
We don’t have any pictures of this specifically but I’ll try and take some Monday at our meeting.
We, Team 228 have a brake on the front of our bot. It was pretty much a requirement as we’re using 4wd with AM Omni’s on the front. It’s a fairly straight forward design, which uses a pneumatic to push a pad down onto the carpet.
If I remember correctly, it’s a 4" throw, 1.5" diameter running at a full 60psi. The pad is about 1.5" x 4" long, with Roughtop belting over the entire patch. Because of the sideloads we anticipated, the friction pad is mounted to two extra shafts running in parallel to the pneumatic shaft, which will take most of the impact loading. These shafts are fed through two mounting plates and slide on bronze bushings.
The entire assembly weights in at about 4 lbs, but we had extra weight which we wanted to put low on the robot anyways. Most of the weight comes from the shafts, which are all 1/2" steel, about a foot long a piece. If we were weight critical, we would have used a much shorter throw pneumatic. This would have greatly cut down on the side loading, and allowed us to use aluminum shafts instead, or even just the pneumatic itself.
Unfortunately, we don’t have any pictures. And, since it was pretty much built on-the-fly, we don’t have any sketches of it either. It worked well enough to keep us positioned, unfortunately we had more trouble with our ball delivery system.
Our brakes dont use any motors or pneumatics and weigh 0 pounds.
Take a guess
Putting the victors on brakes or the driver him/herself?
Nope, good guess though.
Hint, its built in to the drive.
Sounds like a worm drive to me
You are most definately correct. They work very nicely, well once we switched from 5:1 to 10:1. The only way to get us to move is by hitting us really hard.
All i can say is surface area and 60 tread.
The only problem with that is that you are going to lose 30%-40% of your power due to the massive inefficiency of the worm and worm gear (and a more efficient worm gear would be backdrivable).
Well, it’s nice to know that some people do actually have breaks. I believe we had one last year, although I knew a lot less about the robot last year (I don’t think I could have answered my own scouting sheet!) but we don’t have them this year because of weight. (we came in a bit over when we first weighed in).
But people give me the weirdest looks when I ask them if they have breaks while pit scouting. So thanks for proving that it’s not that odd of a question!
Team 293 is using brakes based off of 25’s design:
A servo sticks a pin into a milled out gear in the gearbox.
For the ammount that they weigh, the benefit is huge. If the brakes are on, the wheels don’t turn.
The only problem is that before we got the settings just right, we snapped several servo horns.