ABSTRACT
After g2 is designed the improved method (Method 2) is applied using the equations derived in Sec. 8-2. Utilizing the known structure ofg2 a more accurate calculation of the cross-coupled disturbance from the compensated channel 2 to the uncompensated channel I is achieved. The disturbance and hence the composite bounds are generated, based upon Eq. (8.30). These have smaller magnitude compared to those obtained by Method 7, thus overdesign is reduced
For the same reason as in channel 2, the nominal loop for channel 1 is given by plant case 2. Again, as in channel 2 the templates show a 360° phase difference between the two plant cases of CL = 0.2 and 0.6. But unlike channel 2 there is a magnitude uncertainty evident in the channel 1 templates, see App. E in Ref. 12. The magnitude uncertainty arises due to the strong coupling from channel 2 into channel 1, and also from the difference in the effect of wind disturbance between the 2 classes of A/C plants based on CL. The plants of CL = 0.6 have a larger wind induced disturbance as shown in App. D of Ref. 12. Therefore, these plants have not only more external disturbance, but also larger cross coupling disturbance.
