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We can describe the motion of a robot arm as either periodic or non-periodic:

• Periodic motion occurs when the robot arm repeats the same movement over and over in a regular, predictable pattern—for example, swinging back and forth or rotating in cycles.

• Non-periodic motion occurs when the robot arm adjusts its movement in response to new information, obstacles, or user commands, resulting in an inconsistent or unpredictable pattern.

Instructions:

Add as many motion descriptions from the list below as you can to your chart. For each, decide if the motion is periodic or not periodic, and write a sentence explaining your reasoning. If a motion could be interpreted in more than one way (for example, “lifting boxes”), explain what context or details would make it periodic or not. 

2. A robot arm welding a seam every 10 seconds. 

3. The arm moves from point A to B, pauses, then moves to C in a different direction.  

4. A robot arm painting identical parts on an assembly line.

5. A robot arm lifting and lowering boxes.

6. A robot avoiding a person.

7. A robotic arm navigating debris to locate survivors of natural disaster. 

8. Robot arm placing a tool in an unplanned location.

9. A robot arm assisting with repetitive physical therapy motions. 

12. A robot arm crafting artisanal pottery.

13. A robot arm sorts fruit by ripeness. 

Checklist

• I sorted all motion descriptions as periodic or non-periodic, or explained the context if unsure.

•  I wrote a clear explanation for each choice, based on the provided definitions.

•  I described at least one example where extra details (context) could make a motion periodic or not.

•  I spotted and explained any angle-labeling errors in the examples (if this is in your materials).

•  I answered, in writing, why repeatability is important in factories or engineering.