repeat patrolcontinue along the route
Lesson / Robotics
How Can a Robot Patrol Without Getting Stuck?
The patrol route works until somebody moves a box into it. Add a distance check, choose a recovery action, and make the robot test the route again instead of turning forever.
Lesson plan
Make the normal route work
Define a short patrol with a known start and stop rule.
Add the obstacle question
Choose the signal and condition that interrupt the patrol.
Build recovery
Record the new state, act, and read the sensor again.
Set traps
Test a corner, repeated obstacle, and recovery that might loop forever.
Trace the feedback
Show the sense-decide-act cycle and state one limit.
Learning goals
- Combine a repeated patrol with sensor readings.
- Use a condition to choose a correction.
- Record the patrol's current state.
- Test an obstacle at an awkward point in the route.
- Trace the sense-decide-act loop.
Small examples
if obstacle neardecide when the plan must change
turn and check againmeasure after the correction
state = RECOVERINGrecord the current mode
Guided project
Robot Patrol Challenge
Patrol a route until an obstacle appears, then choose a response that does not involve turning forever in a corner.
A repeatable patrol, An obstacle signal, At least one response state, A correction and recheck.
Loops, Sensors, Conditions, State, Feedback.
A working version with a tested change, one repaired problem, and a clear explanation.
Teacher checkpoints
- 1The normal patrol route works.
- 2An obstacle causes a different action.
- 3The robot reads the sensor again after correcting.
- 4Recovery cannot become an endless turn.
- 5The student traces the sense-decide-act cycle.
Common mistakes
- The patrol loop never reads the sensor.
- One obstacle leaves the robot permanently in recovery mode.
- The robot keeps turning without a new reading.
- There is no rule for ending the patrol.
Optional challenges
Builder
- Stop and signal at an obstacle.
Inventor
- Try a second route after turning.
Boss Level
- Track failed directions and choose a recovery state.
End-of-class demonstration
- What repeats during patrol?
- What does the system sense?
- Which condition changes the plan?
- How does it check the correction?
- What limit remains?