Team 1736 2019 Robot Reveal

FIRST Robot Showcase
#8

From what I’ve seen it looks like a significant judgment call by the Head Ref during matches and LRI at the event. What I recommend to make it less of a judgment call is to make the attachment point more pronounced, so it doesn’t look like you are at de-attaching. If anything goes wrong and it does de-attach the violation is a RED Card.

Sorry if I’m coming off as a pain, I want to make sure you guys are all set.

Good luck this weekend I’ll be sure to watch out for you guys!

This is the part Im worried about:
51%20PM

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#9

No Prob, and thank you for the concern! I do agree, the video makes it look detached, but I’m quite sure we never release it :). I’ll chat with the mentors tonight, I think I can whip up a better picture soon (if not tonight then later this week).

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#10

Knowing you, I’m sure that arm is automated. We are running a button board powered by an Arduino to snap our arm to positions. For a control system we are using a Motion Magic loop with a cosine feedforward value. How are you controlling it, and what are you using for a control system?

#11

Amazing bot! I like the idea of the drop and pick up ramp!

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#12

That ramp is awesome!

I think as long as you can demonstrate to the inspectors that the ramp is constrained such that it can never violate the 30" extension, then you should be good to go.

To be proactive, it might be worth pulling in the LRI during this test, and/or chatting with the head ref to make sure all are clear that it’s been checked and can’t break the rule.

#13

You may have an issue here as the bumpers are outside of the HAB zone but you’re extending outside of the bumper zone.

image
image.jpg755×543 271 KB

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Is there a motor limit? The guidebook is kind of vague
#14

This was my initial thought as well watching. Love the creativity but I’m afraid that its not legal per the bumper zone rules.

#15

Super cool climb. Can not wait to see it. Great work

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#16

That hatch mechanism is very cool. Looking forward to seeing this robot in action.

#17

Are those harbor freight pneumatic wheels? Or red MBS tires?

#18

I wonder how R25 applies here.

Except as allowed per G23, BUMPERS must be located entirely within the BUMPER ZONE, which is the volume contained between the floor and a virtual horizontal plane 7½ in. (~19 cm) above the floor in reference to the ROBOT standing normally on a flat floor. BUMPERS do not have to be parallel to the floor.

Bluebox:

This measurement is intended to be made as if the ROBOT is resting on a flat floor
(without changing the ROBOT configuration), not relative to the height of the ROBOT
from the FIELD carpet. Examples include:
Example 1: A ROBOT that is at an angle while navigating the FIELD has its BUMPERS
outside the BUMPER ZONE. If this ROBOT were virtually transposed onto a flat floor,
and its BUMPERS are in the BUMPER ZONE, it meets the requirements of R25.
Example 2: A ROBOT outside its HAB ZONE deploys a MECHANISM which lifts the
BUMPERS outside the BUMPER ZONE (when virtually transposed onto a flat floor). This
violates R25

Could “resting on a flat floor” be interpreted as “after the robot comes to rest”?

#19

$8 harbor freight special!

#20

Yep, Harbor Freight wheels. They worked well for us in the past so we decided that with the hard bounces to/from level 2 they would be a good choice again. They’re cheap and easily available which is nice, but they aren’t a very standard size (~8.75") and the hubs obviously aren’t made for FIRST.

#21

I don’t think you’d get away with that interpretation.

#22

Also, thanks to all for the notes on the climber. We did revise the geometry of the mechanism after the video was shot. We’re going to go back tonight in our CAD to ensure we’re compliant with G23/R25.

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#23

Well, definitely wasn’t expecting #teamtether to be revived, but here we are. Good luck with inspections and see you all in Peoria!

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#24

I’m super-psyched you guys have a plan! This black magic is absolutely bonkers to watch. Very well-executed!

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#25

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#26

Sorry for the late reply! Yup, arm is automated.

It’s driven off of a single NEO, and we close-loop around the internal encoder.

We did some physics simulations early in the season to prove out that a trivial bang-bang control would promptly tip the robot over, so we investigated other options. We’re currently using the “SmartMotion” feature in the SparkMax, which is trapezoidal motion profiling.

We also were looking to use the arbitrary feed-forward to do a cosine-based gravity compensation. However, it turned out at most it would adjust the motor command by ~3%, which was within the noise range for our application. We ended up just turning it off to simplify operation.

The driver can select between four fixed positions (high/mid/low/ground), as well as adjust the position manually. The intake and gripper automatically are actuated to get them in a safe position to put/extract the gripper within the frame.

Main takeaway from me: NEO motors are awesome. I am totally down for using them on drivetrain next year.

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#28

Paging @Treecko120 :slight_smile: