Team 1538 / The Holy Cows - 2015 Robot: Daisy Quickstep

[kiettyyyy]

Originally Posted by JesseK

What about your 'pincher' requires so much power? Does it do more than pinch? What does it pinch?

Do you have any limit switches anywhere on your robot?

Do you guys powdercoat your stock, and then drill into it?

1) Cans, totes, robots, people, etc. Two motors are dedicated to the 'pinching' function, the other two power the rollers on the pincher.
2) Nope. We've done a fair amount of control theory work and implementation this year. It's been a great experience for our students to be exposed to even more practices that are fairly common in the controls industry.

All of our rezeroing, minimum and maximum positions are determined by using a combination of position gathered using a quadrature encoder and monitoring output current and output voltage.

For example, we'd limit the upper end of our elevator travel based on an estimated position and then we'd calculate how much power is going into the elevator to prevent a motor stall condition.

After profiling the current draw, we determined that it requires a little bit of logic to figure out if we're indeed stalling the gearbox, or lifting a bunch of totes.

We'd also rezero our elevator when it returns to its minimum position. Essentially, we'd allow for the elevator to run past the minimum position. Once we've detected that we're not moving anymore, the position is past the minimum position (our elevator has a spring loaded return cable), and current has trended upward, we can safely say that we're at the minimum position. We'd then allow the elevator to back drive itself via the spring to its natural state where we'd then reset the encoder.

Finally, we're using a quad encoder on our pincher gearbox along with two different PIDs. One PID handles position control so that our drivers can quickly acquire game pieces. Once the game piece is kinda-sorta in our possession, we'd switch to a current based PID.

This ensures that we'd be placing almost an equal amount of force on what ever we decide to grab. This configuration works on game pieces in any orientation. Cans fallen over, Cans upside down, totes from the wide side, totes from the long side, totes that are upside down, you name it.

3) We do not powdercoat our stock and do post machining. It just happened to be on that part, we kind of forgot a few holes. Careful measurements and some patience later along with a handheld drill, we'd have some pretty precise holes.

[JB987]

Are the rollers on the "pincer" polyurethane tubing like McMaster carries?

[kiettyyyy]

Originally Posted by JB987

Are the rollers on the "pincer" polyurethane tubing like McMaster carries?

Maybe

Originally Posted by Kevin Kolodziej

One question: How do you intend to satisfy R2 and have numbers visible from all sides of you robot?

We took them off for the photo shoot. They look a bit funny to us.

[Gweiss96]

I just have to say, this is the coolest looking robot I have seen for this competition. The Holy Cows never fail to impress me with their amazing powder coating. Well done.

[Boltman]

Excellent Bot saw it up close and personal. So glad to see THE CLAW working on final bot! Their wire management is crazy good.

[RoboChair]

That wiring job is so sexy I would date it.

[Abhishek R]

This is the most beautiful robot I've seen this year. Look at those curves, those edges, that wiring, the sponsor plates...holy cow.

[hunterteam3476]

What a beautiful Robot, I can't wait to compete with this at SDR.

[mmaunu]

Impressive, intimidating, and (most importantly) inspiring...as always! I'm looking forward to seeing you play in Arizona and then seeing it for myself in San Diego.

[Maldridge422]

As always, a gorgeous robot with incredible wiring. What kind of connectors are those coming off of the talons? What are the advantages of them compared to Andersons?

[kiettyyyy]

Originally Posted by Maldridge422

As always, a gorgeous robot with incredible wiring. What kind of connectors are those coming off of the talons? What are the advantages of them compared to Andersons?

Those connectors are Deans Ultra connectors. We mainly chose them for the form factor. Also, the plug, including the solder joints, have less resistance than a piece of 12 awg wire of an equivalent length.