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Evolution of Industrial Process Control

You may navigate through this presentation by pressing on the left and right arrows provided below or on any of the process control methodologies whose abbreviated names appear chronologically in the drawing below:

  • Surprisingly, only a few methodologies have been commercially applied in industrial process control

  • Manual Control

    By the middle of the last century most industrial processes were under manual control. When process variables deviated from the desired value or set point, human operators acted on the process trying to correct the error already produced.

  • PID Controllers

    The automation era started with the introduction of PID controllers which produce the control signal by reacting to the error already produced in a proportional (P), integral (I) and derivative (D) manner. Although effective in many cases, PID controllers performance fails to be satisfactory when the process is complex, unknown and time-varying in nature.

  • Expert Systems

    Expert control was introduced in the 1970s trying to fill the gap in process control.

    Expert Systems try to imitate the behaviour of human operators by means of rules. Unfortunatly too many rules are usually required and the performance of these ad hoc systems cannot go beyond that of human operator performance.

  • Adaptive Predictive Control
    Optimized Adaptive Control

    Adaptive Predictive Control (APC) was introduced in a patent application in 1976 and represented a philosophical and practical breakthrough in process control.

    Instead of reacting to the error, it applies "Predictive Control" by means of a "Predictive Model" that is adjusted in real time by an "Adaptive Mechanism" which ensures accurate prediction of the process output.

    The introduction of APC boosted the development of adaptive control techniques, based on the same principles, which are generically called Optimized Adaptive Control (OAC).

  • Model Based Predictive Control

    Predictive Control is also used without adaptation under different formulations named "Dynamic Matrix Control", "Model Predictive Control" or "Multivariable Predictive Control ".

  • Adaptive Predictive Expert Control (ADEX)

    Adaptive Predictive Expert Control (ADEX) was formulated in a patent application in 1999. ADEX introduces the concept of domains, which enables the use of available process knowledge by the controller, and the application of:

    (1) Adaptive Predictive Control to optimize the process operation, or
    (2) Expert Control when needed.

  • ADEX is the result of the most important advances made in control methodologies, and is an ideal tool for optimized process control

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