What is Advanced Process Control?
Over the past 40 years, much have been written about advanced process control; the underlying theory, implementation studies, statements about the benefits that its applications will bring and projections of future trends.
During the 1960s, advanced process control was taken to mean any algorithm or strategy that deviated from the classical three-term, Proportional-Integral-Derivative (PID), controller. The advent of process computers meant that algorithms that could not be realized using analog technology could now be applied. Feed forward control, multivariable control and optimal process control philosophies became practicable alternatives. Indeed, the modern day proliferation of so called advanced control methodologies can only be attributed to the advances made in the electronics industry, especially in the development of low cost digital computational devices (circa 1970). Nowadays, advanced control is synonymous with the implementation of computer based technologies.
It has been reported that advanced process control can improve product yield; reduce energy consumption; increase capacity; improve product quality and consistency; reduce product giveaway; increase responsiveness; improved process safety and reduce environmental emissions. By implementing advanced control, benefits ranging from 2% to 6% of operating costs have been quoted. These benefits are clearly enormous and are achieved by reducing process variability, hence allowing plants to be operated to their designed capacity.
What exactly is advanced process control?
Depending on an individual's background, advanced process control may mean different things. It could be the implementation of feed forward or cascade control schemes, of time-delay compensators, of self-tuning or adaptive algorithms or of optimization strategies. Here, the views of academics and practicing engineers can differ significantly.
We prefer to regard advanced control as more than just the use of multi-processor computers or state-of-the-art software environments. Neither does it refer to the singular use of sophisticated control algorithms. It describes a practice, which draws upon elements from many disciplines ranging from Control Engineering, Signal Processing, Statistics, Decision Theory, Artificial Intelligence to hardware and software engineering.
The Advanced Process Control topics we will be covering in detail are: