Adaptive calibration and control of cascade processes with unknown measurement model and actuator dynamics and its application to paper manufacturing

Many industrial processes are in cascade configuration in which the material being processed goes through a sequence of processing units. The output of an upstream processing unit is fed into the input of the unit downstream. In many cases, the variables of interests are only available via related uncertain surrogate measurements in the all the upstream stages , and directly measured at the output of the last stage. The problem of controlling such systems by adaptively calibrating the surrogate measurement model and the use of a pre-emptive control strategy was studied in [9]. In this paper, the unknown actuator dynamics is taken into account in the adaptive calibration and pre-emptive control as well. A Lyapunov based nonlinear control algorithm is derived. The proposed control algorithm is applied to a vacuum dewatering process in paper manufacturing industry. Simulation results show that the proposed control strategy can regulate the exiting moisture content of each unit at the desired value.