Teacher/Mentor Institute

Hands-On Session:Building a Robot

Scott McEwen & Kevin BarrettJuly 21-22, 2014

Overview

Quick and simplified exposure to what your student team will experience

You will experience some of the same Design choices Building decisions Learning experiences Frustrations

We hope that this will make you a better coach and mentor!

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Caveats

This guide has a suggested procedure for building your robot. You may vary from this procedure so long as you: Do not endanger yourself or anyone else Do not permanently attach anything to the

Returnable Kit parts Do not damage the room or furniture in any way Clean up after yourself

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Be courteous to our hosts!

Please DO NOT scratch the tables, other furniture or floors, or snag any carpet or furniture fabric

Keep a box lid or other surface protector between your work and the furniture or floor

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The Competition

Two robot teams per match; multiple matches.

Game Field: Bounded by PVC Small & big balls Two buckets (one per

team)

Score by placing balls in your bucket.

Small balls = 1 point each

Big balls = 2 points eachPage 5

Platform (1)

Construct/Attach: Plywood base Motors Skid

Make sure the platform is stable and can roll in various directions. Page 6

Platform (2)

Attach Cortex

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Connect Motors to Cortex (1)

Motor Ports 1 & 10 – Built-in motor controller. Not allowed by BEST.

Motor Ports 2-9 – Require external Motor Controller. BEST requires use of ports 2-9.

Motor Ports 1-5 share same overload circuit protection, and Ports 6-10 share same circuit overload protection. Balance motors between ports 1-5 and 6-10.

Use Screw Terminal Motor Interface

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Connect Motors to Cortex (2)

Cortex Motor Port Motor Controller Screw Terminal

Block Motor wires with

Quick Connects Motor Tabs

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Test the Platform (1) easyC: File … New Competition

Project Field Control Competition Project Operator Control tab Joystick … Arcade- 2 motor

into while loop Forward/Reverse Channel: 2 Rotate Channel: 1 Left Motor, Right Motor: (look

where you plugged these in to the Cortex.)

Joystick … JoystickAnalogDeadband => before Arcade

Deadband for both Channel 1 and Channel 2

Test-“drive” the platform – make sure the motors respond correctly

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Wheels

Attach hubs to wheels

Attach hubs to motor shafts

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Arm

Build and attach A-frame to hold arm

Make and attach an arm that is the right size to: Reach to the ground Be pulled down by

the winch

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Winch

Build and attach winch Mount and attach winch motor Wire winch motor to Cortex Edit your program to include winch motor Test Add spool and string to winch and test

again

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Test Drive

1. Go to Build and Download menu. Compile your program. Fix any errors.

2. Connect USB cable between laptop and Cortex. Download your program to Cortex.

3. Tether joystick and Cortex – Connect them with USB cable.4. Turn on Cortex first, then joystick. Wait for ROBOT and

JOYSTICK lights to turn green.5. Test each wheel motor forward and backward. If either wheel

moves in the wrong direction, go back into the program, check or uncheck the box to reverse direction, and try again.

6. Untether the Joystick and Cortex. Turn them off. Insert the 2 VEXNet keys and turn them back on.

7. Drive the platform without the tether.Page 14

Servo

Connect servo to Cortex with a Servo Controller In your program, add a JoystickToServo, and use Channel 5 or

6 (Servos don’t need a deadzone) Turn on Cortex and Joystick. The Servo will rotate to its

“zero” position. Make a note of it.

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Claw

Disconnect the servo from Cortex.

Design and assemble claw, including servo. Make sure it can move properly.

Remember to assemble it so that its starting position coincides with the servo’s “zero” position.

Reconnect the servo to the Cortex. Turn Cortex on and test claw.

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Mount the Claw

Attach the claw to the end of the arm.

Make sure it reaches to the ground and can open and close.

You may need to add a servo extension between the servo controller and the servo.

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The Competition

Two robot teams per match; multiple matches.

Game Field: Bounded by PVC Small & big balls Two buckets (one per

team)

Score by placing balls in your bucket.

Small balls = 1 point each

Big balls = 2 points eachPage 18