Industrial Comparison of an Auto-Tuned PID Regulator and an Adaptive Predictive Control System (APCS)

Abstract

A novel technique for automatically tuning PID controllers and an adaptive-predictive control scheme (APCS) have been applied to the same loop in an industrial bleach plant. The PID uses a linearizing block and gain scheduling to compensate for sensor non-linearities and production rate changes while APCS treated the latter as an unknown perturbation. Both schemes gave excellent performance and proved very reliable. This shows that, when non-linearities are known and changes in process dynamics are predictable, then gain scheduling combined with a well-tuned PID regulator behave remarkably well. At the same time, the results have also shown that adaptive control can easily handle this situation with less tailoring.