In Section 12.2 (feedforward design) you have put a new subsection titled Sensitivity to Process Varations that works through the sensitivity of the feedforward design to variations in the process model. This same type of material occurs in Chapter 13, where we do the same type of derivation, although for the “standard” controller design (rather than the more complex feedforward computations here). I was wondering if it makes sense to include the “robustness” analysis here in Chapter 12 rather than in Chapter 13 (titled “Robust Performance”).
I was thinking that an alternative would be to move this subsection into Chapter 13. The problem there is that we don’t really have the feedforward design discussion. One possibility would be to create an exercise in Chapter 13 in which we ask students to show that for the diagram in Figure 12.2 they obtain the properties listed in Table 12.2 (we could list the table, so that the results are explicitly given).
Let me know what you think. I am worried that the current (new) material introduces a topic that is really best handled in the next Chapter (specifically in Section 13.3, titled “Performance in the Presence of Uncertainty”).