Unformatted text preview: ches the sustained oscillat ion condit io n result ing in a limit ing value for the controller gain of 51 consistent with the results obtained before. However, in this case, we also obtain the value of the ult imate period Pu = 0.9 . Wit h these two values, using Table 12.3, we can calculate the ZN controller settings as: k c = 22.95 t I = 0 75 ; . Figures 30 and 31, show the closedloop performance under a PI controller using the ZN settings for both setpoint tracking and disturbance rejection. Figure 28: Closedloop response with a Pcontroller using k c = 20 . Figure 29: Closedloop response with a Pcontroller using k c = 51 . Figure 30: Closedloop response with a PI controller for a setpoint change using
k c = 22.95 t I = 0 75 (ZN settings). ; . Figure 31: Closedloop response with a PI controller for a disturbance using k c = 22.95 t I = 0 75 (ZN settings). ; . Next, the stabilit y margins are calculated using the Bode Stabilit y Criterion for both gain and phase. The results are displayed in Figure 32 and they are 25 and 1.87 for the phase and gai...
View Full Document
- Fall '08
- WCO, Closedloop response