350 likes | 902 Views
Fuzzy PID Control. Reduce design choices Tuning, stability Standard nonlinearities. Design Procedure *. Build and tune a conventional PID controller first. Replace it with an equivalent linear fuzzy controller. Make the fuzzy controller nonlinear. Fine-tune the fuzzy controller.
E N D
Fuzzy PID Control Reduce design choices Tuning, stability Standard nonlinearities
Design Procedure* • Build and tune a conventional PID controller first. • Replace it with an equivalent linear fuzzy controller. • Make the fuzzy controller nonlinear. • Fine-tune the fuzzy controller. *) Relevant whenever PID control is possible, or already implemented
n l Ref e u x y Plant Controller - Single Loop Control
Rule Base With 4 Rules 1. If error is Neg and change in error is Neg then control is NB 3. If error is Neg and change in error is Pos then control is Zero 7. If error is Pos and change in error is Neg then control is Zero 9. If error is Pos and change in error is Pos then control is PB
e E u U GE GU f Rule base Fuzzy P controller
FP Rule Base 1. If E(n) is Pos then u(n) is 100 2. If E(n) is Zero then u(n) is 0 3. If E(n) is Neg then u(n) is -100
e E GE u U f GU CE de/dt GCE Rule base Fuzzy PD Controller
FPD Rule Base 1. If E(n) is Neg and CE(n) is Neg then u(n) is -200 3. If E(n) is Neg and CE(n) is Pos then u(n) is 0 7. If E(n) is Pos and CE(n) is Neg then u(n) is 0 9. If E(n) is Pos and CE(n) is Pos then u(n) is 200
e E GE u U f + GU de/dt CE + GCE PD rules IE GIE Fuzzy PD+I Controller
e E GE CU cu f 1/s U GCU de/dt CE GCE Rule base Fuzzy Incremental Controller
n l Ref e u x y Plant Controller - Tuning
Ziegler-Nichols Tuning • Increase Kp until oscillation, Kp = Ku • Read period Tu at this setting • Use Z-N table for approximate controller gains
Hand-Tuning • Set Td = 1/Ti = 0 • Tune Kp to satisfactory response, ignore any final value offset • Increase Kp, adjust Td to dampen overshoot • Adjust 1/Ti to remove final value offset • Repeat from step 3 until Kp large as possible
e E α GE u U f 1/α GU CE de/dt α GCE Rule base Scaling
Kp = 4.8, Ti = 15/8, Td = 15/32 2 1 0 -1 -2 -2 0 2 Nyquist 1/(s+1)3 with PID
000 001 010 011 2 2 2 2 0 0 0 0 -2 -2 -2 -2 -2 0 2 -2 0 2 -2 0 2 -2 0 2 a) c) d) b) 101 100 110 111 2 2 2 2 0 0 0 0 -2 -2 -2 -2 -2 0 2 -2 0 2 -2 0 2 -2 0 2 e) g) h) f) Tuning Map 1/(s+1)3
2 200 1.5 0 u Controlled output y 1 -200 0.5 100 100 0 0 0 -100 -100 0 10 20 30 40 CE E 6 1 0.8 4 0.6 Control signal u Membership 2 0.4 0 0.2 -2 0 0 10 20 30 40 -100 -50 0 50 100 Time [s] Input family: Neg and Pos 1/(s+1)3 with FPD+I
Summary • Design crisp PID • Replace it with linear fuzzy • Make it nonlinear • Fine-tune it