3 robots designs I hope to see this season

[CalTran]

That would be quite a site to see. It may end up being something like the 2337/2959 suspension of MSC back in 2010. But I agree with Tom I, I would most certainly not trust putting anyone on top of our robot. Imagine if something were to go wrong! The humanity of suddenly having 150lbs of robot suddenly falling on our baby! *gasp*

[Djur]

Originally Posted by Katie_UPS

I wanna one-up the half court shooter. I wanna see a robot that can line up in front of the feeder station and pitch-machine top hoop goals consistently. I'm not well-versed on motor math, so I have no idea how feasible this is, but its something I'd like to see.

Seconded!

[Alpha Beta]

Originally Posted by CalTran

But I agree with Tom I, I would most certainly not trust putting anyone on top of our robot

I think the specialty robot would go on bottom. Show me you can do it, and I'd put mine on top for the extra 20 points.

The bridges in the practice area are going to be very busy during the saturday lunch break. Teams would bennfit from having extra bridges available at this time.

[apalrd]

Originally Posted by Hawiian Cadder

I think that another type of robot which could be neat is one where another robot is able to drive on top of it, and then both balance as a unit.

Like This robot (another pic)

[JesseK]

Assuming a 60 degree arc length of contact on a 8" 1-wheel shooter at ~2400 RPM, the ball needs a minimum of 500 watts transferred to it after inefficiencies in order to go 54 feet (~42 ft/s for middle goal). This is doable with a heavy flywheel that has plenty of spin-up time and 4 Banebots RS-550 motors connected to the same wheel. At 63% overall efficiency, that's ~67 amps of current while a ball is in the shooter. If you sit in one spot, that's chump change.

The kinematic equations are your friends this year.
Vf^2 = Vi^2 + 2 * a * d
You have D, Vf, and Vi. You can find a, which then can give you required force via F = m * a, and then a torque via Tau = Force * radius of the wheel. Then you can multiply Torque (N*m) * Wheel speed (rotations / second) and you get power required.

Of course, that assumes a perfect flywheel effect and a perfect contact patch between ball and wheel, so YMMV. Prototype it.

It also assumes that a 84" tall robot will never block the shot, heh. We aren't even attempting it because the trajectory length is so long that a variance of ~0.7 degrees in the shooter causes the shot to miss. That's not worth putting 4 motors on the shooter.

[Joe Ross]

Originally Posted by apalrd

Like This robot (another pic)

How about this: http://www.chiefdelphi.com/media/photos/27756

[JamesCH95]

Originally Posted by JesseK

Assuming a 60 degree arc length of contact on a 8" 1-wheel shooter at ~2400 RPM, the ball needs a minimum of 500 watts transferred to it after inefficiencies in order to go 54 feet (~42 ft/s for middle goal). This is doable with a heavy flywheel that has plenty of spin-up time and 4 Banebots RS-550 motors connected to the same wheel. At 63% overall efficiency, that's ~67 amps of current while a ball is in the shooter. If you sit in one spot, that's chump change.

The kinematic equations are your friends this year.
Vf^2 = Vi^2 + 2 * a * d
You have D, Vf, and Vi. You can find a, which then can give you required force via F = m * a, and then a torque via Tau = Force * radius of the wheel. Then you can multiply Torque (N*m) * Wheel speed (rotations / second) and you get power required.

Of course, that assumes a perfect flywheel effect and a perfect contact patch between ball and wheel, so YMMV. Prototype it.

It also assumes that a 84" tall robot will never block the shot, heh. We aren't even attempting it because the trajectory length is so long that a variance of ~0.7 degrees in the shooter causes the shot to miss. That's not worth putting 4 motors on the shooter.

500 watts for what length of time?

[JesseK]

Originally Posted by JamesCH95

500 watts for what length of time?

Well, since I know the watts required, and the distance of the arc length in the shooter wheel, I suppose we can calculate time since [Power = Force * distance / time]. Yet the rotational power required was calculate via [Power = Torque * Rotation Speed]. Thus we didn't need time. It does make a couple of assumptions, such as Power In = Power Out (power required by the ball is available in the shooter wheel).

The whole point of the exercise is to figure out what motors to use and what shooter wheel radius to use. It's "doable", but personally I wouldn't bet my season on it being successful.

[JamesCH95]

Originally Posted by JesseK

Well, since I know the watts required, and the distance of the arc length in the shooter wheel, I suppose we can calculate time since [Power = Force * distance / time]. Yet the rotational power required was calculate via [Power = Torque * Rotation Speed]. Thus we didn't need time. It does make a couple of assumptions, such as Power In = Power Out (power required by the ball is available in the shooter wheel).

The whole point of the exercise is to figure out what motors to use and what shooter wheel radius to use. It's "doable", but personally I wouldn't bet my season on it being successful.

Okay, I didn't see anywhere that you assumed length of time/distance over which the ball would be in contact with the wheel and was curious. I also wanted to make sure you didn't have a units jumble somewhere.

[JesseK]

Originally Posted by JamesCH95

Okay, I didn't see anywhere that you assumed length of time/distance over which the ball would be in contact with the wheel and was curious. I also wanted to make sure you didn't have a units jumble somewhere.

Heh, distance was in the first few words of the post, but perhaps it should be "8-inch diameter 1-wheel shooter". And personally before I run calculations I convert everything to metric since most of the motors specs I have are metric (Newton-meter for torque). The units check out.

[LafondaOnFire]

I'd love to see a robot that basically blocks the view of drivers. Since you can extend to 84 inches up and 14 inches out on the side of the field where you score, that is right in front of the opposing alliance's drive team right? Well I'm wondering if a team will abuse this fact and have a giant blanket to completely obstruct a drive team's view of the entire field. What a predicament that would be!

The drive team would need to rely on instructions from the Inbounders or other teams as to how to navigate their robot. This sort of robot would be a fantastic third pick for any alliance. With two solidly scoring robots, just pick a third as an annoyer. Well, more than an annoyer. It might deem teams unable to score or balance the bridge since they can see nothing.

[Ninja_Bait]

*cough*R08*cough*

[EricH]

Originally Posted by LafondaOnFire

I'd love to see a robot that basically blocks the view of drivers. Since you can extend to 84 inches up and 14 inches out on the side of the field where you score, that is right in front of the opposing alliance's drive team right? Well I'm wondering if a team will abuse this fact and have a giant blanket to completely obstruct a drive team's view of the entire field. What a predicament that would be!

There's a chain of rules that will lead in the general direction of a Red Card if this strategy is attempted. [R01] starts the chain (inspection will keep the robot off the field), then you get the safety rules and egregious behavior rules, as well as having to be legal to compete (and failure to be legal is a disablement at minimum).

[LafondaOnFire]

Originally Posted by EricH

There's a chain of rules that will lead in the general direction of a Red Card if this strategy is attempted. [R01] starts the chain (inspection will keep the robot off the field), then you get the safety rules and egregious behavior rules, as well as having to be legal to compete (and failure to be legal is a disablement at minimum).

Well if you start 60 inches tall or less and have no appendages outside the perimeter of the frame would it still be an issue with R01? The only other possible rule violation I found is [G07]

[G07]
If at any time a Robot’s operation or design is deemed unsafe, the Robot will be disabled for the remainder of the Match. If the safety violation is due to the Robot design, the Head Referee has the option to not allow the Robot back onto the Court until the design has been corrected.
Violation: Foul and disablement

An example of unsafe operation would be uncontrolled motion that cannot be stopped by the Drivers.

So the only concern I could think of is that it is unsafe to blindly be driving your robot on the field. Since the actions are fully intentional, it would have to cause an unsafe situation on the field.
If I missed a rule that does indeed clearly prevent this idea, please point it out. I can't find anything else in particular but it would be great for future reference. Not to mention I'd never see this idea

[JesseK]

Really, if you so wholeheartedly believe you will get away with blinding the opponents with a 84" blanket, go ahead. Just don't come crying to CD when you don't get to compete.