PID Control system for Dummies

We look at the past, consider the present, predict the future and adjust the output accordingly... That's PID!

1. PID & Control How do quadcopters fly? ABARA JITHAN . G

2. Quadcopter Flight Control Robots Self Driving Cars Air conditioner When we need to automatically control something…

3. We are a feedback control system!! Try walking / writing with your eyes closed! Feedback Control Observe the Effect Make changes

4. Air conditioner Our room is at 30°C. We need to : Cool down it to 22°C Within a shortest time. Maintain the temperature at 22°C against external effects.

5. On-Off control Can’t control the power: only ON - OFF Disadvantage: Temperature oscillations Unstable System Switch On A/C Switch Off A/C Temperature < 22°C Temperature > 22°C

6. PID Control System Remember the PAST (Integral) Consider the PRESENT (Proportional) Predict the FUTURE (Derivative) And adjust power accordingly…

7. ERROR Air condition in a room Error will be changing over time. Error 8 °C Process Variable 30°C Set Point Value 22°C = -

8. Proportional Control Consider the present Concept : Reduce power gradually   Where is proportional gain (we need to tune)   Reduce power of A/C gradually, until temperature = 22°C

9. Steady state error may occur in pure proportional control. We don't have this in reality. Systems have momentum – The room has heat capacity Add small overshoot Proportional control…

10. Integral Control Remember the past! Concept : If past has high errors, increase the power Integral : Sum of errors over time   Where is integral gain (we need to tune)   If temperature doesn’t settle for a long time, apply more power

11. Proportional-Integral control… Removes steady state error Tends to introduce overshoot! Increases relaxation time should be very small to prevent overshoot  

12. Derivative Control Predict the future! Concept : If room cools slowly, increase the power   Where is derivative gain (we need to tune)   eg : Empty room cools fast  Use low power Water filled room cools slowly  Use high power

13. PID Equation Power =   Error   Sum of past errors over time   How fast error changes + +   Math : Second Order Ordinary Differential Equation are constants to be determined by careful tuning  

14. are tuned to have Minimum relaxation time Minimum steady state error Minimum oscillations / vibrations   PID Equation Power =   Error   Sum of past errors over time   How fast error changes + +

15. Arduino Code No need of advanced math!

16. To self balance 3 axes – Adjust angle (3 PID equations, 9 constants to be tuned) Error - Measured by a gyroscope module, Power - Given to the motors Quadcopters, Aircrafts

17. THANK YOU Presentation by: ABARA JITHAN . G