Step Change In Set Point Research Articles

Experimental evaluation of optimal, multivariable regulatory controllers with model-following capabilities

The formulation of the optimal, linear, time-invariant, multivariable control problem with quadratic performance index is extended so that the solution includes multivariable integral feedback and model-following capabilities in addition to the normal proportional state feedback. The integral action is produced by augmenting the state vector, and eliminates offsets in selected output variables due to constant disturbance inputs. Inclusion of a setpoint vector in the performance index resulted in relatively high controller gains and a fast process response to step changes in setpoints. However, the “real” model-following approach for implementing step changes in setpoints gave greater design flexibility and reliable process responses. The practicality and excellent performance of control systems developed using this approach is demonstrated by experimental data from a computer-controlled pilot-plant evaporator at the University of Alberta.