Robust temperature control of a semibatch polymerization reactor: frequency domain specifications

A frequency domain (FD)-based solution to the temperature regulation problem for a semibatch emulsion polymerization reactor is presented. The problem considered is an industrial case study that is representative of the types of control problem found in the speciality chemicals industry. Heuristics are presented for defining an FD spec that is approximately equivalent to the given time domain spec. The FD-based method is shown to provide a simple means of modifying any design to handle a wide class of realistic measurement noise models. An important advantage of the FD approach in terms of enabling the design of linear controllers for tracking slowly varying temperature trajectories is also highlighted. (C) 1998 Elsevier Science B.V.