Subsumption Architecture

Concurrent Behavior Layers with Priority-Based Suppression

START MAIN LOOP
↓
LAYER 3: ESCAPE
(HIGHEST PRIORITY – Suppresses All Below)
Check Sensor
IN8 = 0?
→
Action:
• Turn 300°
• Blink LED 5x
• Audio Alert
⚠ SUPPRESSES Layers 1 & 2
↓
If IN8 ≠ 0
LAYER 2: OBSTACLE AVOIDANCE
(MEDIUM PRIORITY – Suppresses Layer 1)
Sensor Check
IN4=1 AND IN7=0?
Turn Left
⊗ Suppresses Wander
Sensor Check
IN4=0 AND IN7=1?
Turn Right
⊗ Suppresses Wander
Sensor Check
IN4=1 AND IN2=1?
Move Backward
⊗ Suppresses Wander
↓
If no obstacles detected
LAYER 1: WANDER
(LOWEST PRIORITY – Default Behavior)
Condition
No Higher Priority Active
→
Action:
• Move Forward
• Explore Environment
ⓘ Always running unless suppressed
RETURN TO MAIN LOOP

Key Subsumption Principles

✓ Concurrent Operation
All layers check sensors every loop iteration
✓ Priority Suppression
Higher layers override lower layers instantly
✓ Fast Response
Short action pulses allow rapid sensor checking
✓ Layer Independence
Each behavior operates autonomously