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ADM Python P.9

Functions for Reusable Workcell Actions

Turning repeated robot sequences into reusable functions.

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Your lesson guide

Objective

Define and call functions Pass values into functions Use functions to organize robot actions

Materials

For the online work: a browser and your engineering notebook. Follow the activity’s materials list for any physical build, and get teacher approval before using equipment.

Plan your time

Suggested work block: 45–60 minutes. Physical builds and projects may span several classes; follow your teacher’s schedule.

Learning Targets

  • Define and call functions
  • Pass values into functions
  • Use functions to organize robot actions

How to Use This Page

  1. Read the short lesson.
  2. Attempt every Practice Check before revealing the answer.
  3. Complete Predict It and Fix It without running the robot.
  4. Complete Modify It and Program It in VEXcode.
  5. Use the Mastery Check before moving to the next lesson.
Learn It

Python Idea + Workcell Connection

A function gives a name to a reusable block of code. This makes longer Workcell programs easier to read, test, and modify.

Values listed in the function definition are parameters. Values supplied when the function is called are arguments.

Functions are especially useful for repeated actions such as pick up, place, move safe, or release.

Worked Example

Trace This Code

Read every line before opening the practice check.

def move_to_pickup(x, y, z):
    arm.move_to(x, y, 120)
    arm.move_to(x, y, z)
    arm.set_end_effector_magnet(True)
    arm.move_to(x, y, 120)

move_to_pickup(100, 150, 45)
Practice Check A

Check Your Understanding

  1. What are the three parameters?

    Check Answer

    x, y, and z

  2. What x-value is used when the function is called?

    Check Answer

    100

  3. How many arm movement commands are inside the function?

    Check Answer

    3 movement commands

Rule: If you missed more than one question, reread Learn It and trace the example again before continuing.

1 · Predict It

Trace Before Running

What values are passed into x, y, and z when the function is called?

Do first: Write your answer in your engineering notebook.

Reveal Self-Check

x = 100, y = 150, z = 45.

2 · Fix It

Debug the Program

Find and correct every error before opening the answer.

def move_to_pallet(x, y, z)
    arm.move_to(x, y, z)

move_to_pallet(250, 80, 120)
Reveal Debugging Check

Add a colon at the end of the function definition: def move_to_pallet(x, y, z):.

3 · Modify It

Change Working Code

Add a second function called release_part() that turns the magnet off.

Success Check

  • Your code runs without a syntax error.
  • The change affects only the intended Workcell behavior.
  • You can explain what changed and why.

Evidence: Paste the revised code into your engineering notebook.

4 · Program It

Build It Yourself

Write one function for picking up a part and one function for placing a part. Call both functions to complete one cycle.

Before You Finish

  • Trace the code once by hand.
  • Check variable names, colons, parentheses, and indentation.
  • Verify that the coordinates and logic match the written scenario.
  • Add useful comments.
Interactive Practice

Python Practice Lab

Edit the code, predict the output, then click Run Code. No physical Workcell is connected.

Browser Python

P.9 Practice

Ready
Output / Errors
Predict what the code will do, then click Run Code.

Tip: Press Ctrl+Enter (Cmd+Enter on Mac) to run. The mock arm object prints simulated Workcell actions instead of controlling hardware.

Practice Check B

Explain Your Code

Without looking back at Learn It, answer these in your notebook:

  1. What Python structure or idea did you use?
  2. What physical Workcell behavior did it control?
  3. What mistake would cause the code to behave incorrectly?
What a Strong Response Includes

A strong response names the Python idea accurately, connects it to a specific robot action or decision, and identifies a realistic syntax or logic error from this lesson.

Mastery Gate

Ready for the Next Lesson?

  • □ I can define and call a function.
  • □ I can pass coordinates into parameters.
  • □ I can organize repeated Workcell actions into reusable functions.

Move on only when you can check every statement. If one is still uncertain, revisit the worked example or redo Fix It before continuing.

Command Reference

VEX Workcell Python API

Use the official VEX API to verify method names and parameters. The examples use the configured arm name arm; use the device name configured in your own VEXcode project.

Open EXP Workcell Arm API
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Build your lesson report

Checkpoint: is your evidence ready?
  • Check calculations, units, labels, and measurements against the activity requirements.
  • Record what actually happened, including unexpected results.
  • Explain what you changed and why; attach required drawings, photos, CAD, or code in your classroom assignment.

Submit the evidence specified in the activity and your classroom assignment. The report below collects your notes, calculations, observations, and reflections; attach any required drawings, photos, CAD, or code separately.

A PDF download is not a submission. Review it, then upload it and any required attachments through your classroom assignment system.