Appendix C
Manually Setting PID Constants
69
Increasing Fuzzy Strength
Excessive overshooting
Excessive undershooting
External
disturbance
Temperature
Set point
Time
Smaller overshooting
Smaller undershooting
Temperature
External
disturbance
Time
Set point
Increasing Fuzzy Scale 1
Excessive undershooting
External
disturbance
Temperature
Set point
Time
Smaller undershooting
Temperature
Excessive overshooting
Smaller overshooting
Vibration
Decreased vibration
External
disturbance
Set point
Time
Reducing Fuzzy Scale 1
Excessive undershooting
External
disturbance
Temperature
Set point
Time
Smaller overshooting
Temperature
Slow stabilization
Quick stabilization
External
disturbance
Time
Set point
The following table shows the tendency of external disturbance response when fuzzy constants are adjusted.
Fuzzy constants
External disturbance response
Excessive
value
Oscillation
Stabilization
time
Fuzzy strength
Larger
Decreases
Increases
---
Smaller
Increases
Decreases
Fuzzy scale 1
Larger
Increases
Decreases
Long
and fuzzy
scale 2
Smaller
Decreases
Increases
Short
Excessive value:
Overshooting or undershooting
Oscillation:
Hunting