Adaptive control of a heat exchanger

A simple feedforward adaptive scheme is applied for temperature control of a heated airstream. The system exhibits different thermal time constants for heating and cooling and nonlinear static characteristics. The control scheme consists of a fixed regulator, to which an adaptive feedforward signal is added to improve tracking transients. Adaptation acts only during reference changes, and its effect is reduced to an integral action in steady state. The adaptive feedforward scheme is shown to improve the tracking and regulation performance obtained from a well-tuned PI controller with a fixed linear feedforward.