The engineer introduced in Problem 8.9 examines the chemical process more carefully and discovers that all the uncontrollable modes with concentration as control variable are asymptotically stable with sufficiently fast dynamics. Why is it possible for the engineer to design an acceptable controller with reagent concentration as the only control variable? If such a design is possible, give reasons for the engineer to prefer it over a design requiring additional control variables.
Problem 8.9
An engineer is designing a control system for a chemical process with reagent concentration as the sole control variable. After determining that the system is not controllable, why is it impossible for him to control all the modes of the system by an innovative control scheme using the same control variables? Explain, and suggest an alternative solution to the engineer's problem.