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ADM Unit 1 | Mission Brief 1.3

Compare Absolute and Relative Motion

Program the same geometric production path using absolute and relative motion, then recommend the better method.

Intermediate1 class periodSkill Builder
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Background

Engineering Context

Precision Robotics is creating reusable code for several similar workcells. Engineers disagree about whether the path should be programmed with absolute coordinates or relative increments. You must test both approaches using the same task.

Objectives

What You Will Practice

  • Distinguish absolute and relative robot movement
  • Create equivalent programs using two motion strategies
  • Compare readability, editability, and execution
  • Support a programming recommendation with evidence
Equipment

What You Need

  • VEX CTE Workcell
  • 6-Axis Arm with drawing tool or simulated points
  • Python project
  • Stopwatch
  • Engineering notebook
Procedure

Instructions

  1. Choose a rectangular or stepped path with at least eight movements.
  2. Sketch the path and label the starting coordinate and all dimensions.
  3. Program Version A using absolute move_to() coordinates.
  4. Program Version B using move_inc() for repeated or dimension-based moves.
  5. Run each version three times and record execution time and positioning success.
  6. Change the path width by 20 mm in both programs. Record how many lines or values had to change.
  7. Compare code length, readability, reuse, and risk of accumulated error.
  8. Write a recommendation for a factory that may move the fixture later.
Requirements

Engineering Requirements

  • Both programs must complete the same path
  • Use at least eight motion commands
  • Complete three successful trials per version
  • Include comments that identify the coordinate strategy
Constraints

Constraints & Safety

  • Use identical speed settings for both versions
  • Do not alter the physical workcell between trials
  • Begin from the same Home position
  • Keep the tool above the approved surface
Deliverables

What You Submit

  • Absolute-motion program
  • Relative-motion program
  • Timing and editability comparison table
  • Annotated path sketch
  • Written recommendation
Reflection

Reflection Questions

  1. Which method was easier to understand?
  2. Which method was easier to resize?
  3. Where could relative error accumulate?
  4. When would a hybrid approach be best?
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