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Let's get the obvious out of the way. The tilting claw layout borrows heavily from 1114's 2008 design. We knew it worked well for them (duh) and figured why go crazy reinventing that particular wheel...er claw. We happily borrow concepts from successful robots of yore.
Now with intentionally horribly-edited video!
https://www.youtube.com/watch?v=eegVXysXSjA (probably blocked on mobile and PC's in most industrialized nations) - all of the practice field footage in this vid was from our Monday night practice session.
Here's an uncut video of an extended battery-drainer run from the end of Monday's practice - https://www.youtube.com/watch?v=kjrBeGeOCcU
Robot Stuff:
Frame/Drivetrain:
6WD West Coast Layout, 2"x1"x1/8" aluminum welded base frame, 1"x1"x1/8" welded upper base
2 WCP 3-CIM WCD DS Shifters, 2.92 spread
Combination of 4" x 1.5" Colson wheels and custom 4" x 1.5" performance wheels with nitrile tread
Arm-mounted Launcher:
Rack and Pinion-driven Linear Punch Mechanism - 1" igus aluminum rod supported by 2 igus 1" open-top pillow block plastic linear bearings. The open top permits the rack gear attached to the 1" rod to slide freely through the bearings.
Cocking mechanism is a custom Mini-CIM driven 106:1 gearbox with steel AndyMark gears. Output is a 56-T pinion gear with 17 teeth cut off. Provides between 6-7" of rack stroke before trip point is hit. No winch here!
Inductive proximity endpoint sensing using sensors from automationdirect.com.
Launching force provided by 2 Century Spring extension springs each with a 80 lb. load at max stretch.
Launching force can be varied between two settings via 2 1.5" bore cylinders that pre-stretch the springs an additional 3" in long shot mode.
Tilt Arm:
Powered by a single 1.5" bore, 8" stroke pneumatic cylinder coupled to arm via a linkage. Provides 120 degrees of tilt motion. Multi-position capable. A semicircular plate on the tilt arm defines five different locking positions - straight up/home (90 degrees above horizontal), short truss pass/layup shot (60 deg), goal shot/long truss pass (38 deg), horizontal pass (0 deg), and ground load (-30 deg).
A separate lock cylinder mechanism driven by a 1-1/16" bore, 1" stroke cylinder controls the positioning with help from a Cherry AN8 Hall Effect analog angle sensor.
Claw:
Kept it simple, 1114-style. Finger pivots via 2 2" stroke 3/4" bore cylinders. Roller claw is a BAG motor into a 10:1 VersaPlanetary. Claw Banebots wheels are polycord belt driven to provide clutch action. Bent and welded tubing forks on the bottom. Not pictured are aluminum winglets that will be added later shortly to assist with catching and stabilizing the ball during "active" shooting.
Diffuse photoelectric sensor from automationdirect.com serves as a ball detection means.
Autonomous:
Will utilize an infrared retroreflective sensor to detect hot goal. Gyro and encoder sensors onboard for navigation.
Extremely reliable 1-ball auto with potential for a 2-ball.
Team 48 will be competing at Crossroads, Wisconsin, and Pittsburgh.
Discussion
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25-02-2014 09:04
eddie12390
Re: pic: 2014 Team 48 Robot - xtremachen17
Looks good, looking forward to being able to see it in person in California
25-02-2014 09:51
mathking
Re: pic: 2014 Team 48 Robot - xtremachen17
That is a really nice design Travis. I am glad you are going to Crossroads so I will get to see it in person.
25-02-2014 09:55
Racer26
Re: pic: 2014 Team 48 Robot - xtremachen17
So if I'm understanding correctly:
The cocking mechanism is wound up and released by spinning the motor in the same direction (until it hits the cut-off teeth, where release happens)?
Neat approach. I assume there'd have to be some position feedback on where the launcher is currently cocked to.
Also like the pneumatic claw rotater. How are you getting it to stop in the various positions mid-travel? Some sort of center-off valve? I'm sure you remember 1075's 2007 arm, where we had to do crazy things with multiple valves valving the exhaust because of pneumatics rules at the time.
25-02-2014 10:08
Travis Hoffman
Re: pic: 2014 Team 48 Robot - xtremachen17
|
Originally Posted by Racer26
So if I'm understanding correctly:
The cocking mechanism is wound up and released by spinning the motor in the same direction (until it hits the cut-off teeth, where release happens)? Neat approach. I assume there'd have to be some position feedback on where the launcher is currently cocked to. |
Just endpoint sensing. We retract full speed for a pre-set time then retract slowly until the retract prox is made. Re-$@#$@#$@#$@# [<<--- HAHAHAHAHA] time is in the sub 1.5 second range, I think. I'd personally prefer angle position awareness of the pinion at all times, but it seems to work really well as-is.
| Also like the pneumatic claw rotater. How are you getting it to stop in the various positions mid-travel? Some sort of center-off valve? I'm sure you remember 1075's 2007 arm, where we had to do crazy things with multiple valves valving the exhaust because of pneumatics rules at the time. |
26-02-2014 08:05
D_Price
Re: pic: 2014 Team 48 Robot - xtremachen17
Can't wait to see you guys again in Pittsburgh. Very nice robot as always!
26-02-2014 08:45
Travis Hoffman
Re: pic: 2014 Team 48 Robot - xtremachen17
Now with intentionally horribly-edited video!
https://www.youtube.com/watch?v=eegVXysXSjA (probably blocked on mobile and PC's in most industrialized nations) - all of the practice field footage in this vid was from our Monday night practice session.
Here's an uncut video of an extended battery-drainer run from the end of Monday's practice - https://www.youtube.com/watch?v=kjrBeGeOCcU
28-02-2014 23:30
Travis Hoffman
Re: pic: 2014 Team 48 Robot - xtremachen17
Added some new claw features today.
http://youtu.be/VKqFY-zxGjE
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