USE OF RESIDUALS IN IDENTIFICATION AND CONTROL OF 2-INPUT,SINGLE-OUTPUT SYSTEMS

Linear and nonlinear identification techniques are examined for the feedforward control of chemical engineering systems with measurable load disturbances. The method developed by Narendra and Gallman, to establish the polynomial gain function followed by a pulse transfer function, is extended to two-input systems through the consideration of residuals. The resulting iteration procedure, which alternately estimates the coefficients of the two parallel single-input branches, exhibits rapid convergence and yields an unbiased estimate for the model of the entire system. This identification procedure, used in conjunction with a feedforward control algorithm, is tested experimentally with a heat exchanger. The water flow rate disturbances can be compensated by adjusting the steam flow rate to yield the desired temperature of the heated water. © 1969, American Chemical Society. All rights reserved.