Section 4.1 Traditional Design Methods RZN Tuning Z-N method:The most widely used method Disadvantage:The resulting PID controller usually gives excessive overshoot A solution:Refined Z-N (RZN)method.Perhaps the most famous improved method The modified PID controller is ()=()(()dt+T de(t) Band u are determined by extensive simulation studies.Define Normalized gain:K=KK,Normalized time delay:0=0/T 4口，404注4生定分QC Zhang.W.D..CRC Press.2011 Version 1.0 6/71Section 4.1 Traditional Design Methods RZN Tuning Z-N method: The most widely used method Disadvantage: The resulting PID controller usually gives excessive overshoot A solution: Refined Z-N (RZN) method. Perhaps the most famous improved method The modified PID controller is u(t) = Kc  [βr(t) − y(t)] + 1 µTI Z e(t)dt + TD de(t) dt  β and µ are determined by extensive simulation studies. Define Normalized gain:Kn = KKu, Normalized time delay:θn = θ/τ Zhang, W.D., CRC Press, 2011 Version 1.0 6/71