Arrangement of integrated module predicting control and optimizing block and observation display

Abstract

An optimization technique for use in driving a process plant controller, such as a model predictive controller, uses an organized, systematic but computationally simple method of relaxing or redefining manipulated, control and / or auxiliary variable constraints when there is no feasible optimal solution within pre-established constraints, to thereby develop an achievable solution for use by the controller. The optimization routine uses penalized slack variables and / or redefines the constraint model in conjunction with the use of penalty variables to develop a new objective function, and then uses the new objective function to determine a control solution that bests meets the original constraint limits.

Description

[0001] This application is a continuation of, and claims priority from, US Patent Application Serial No. 10 / 241,350, filed September 11, 2002, and entitled "Integrated Model Predictive Control and Optimization in Process Control Systems." technical field [0002] The present invention relates generally to process control systems, and more particularly to the use of optimal model predictive controllers in process control systems. Background technique [0003] Process control systems, such as those used in chemical, petroleum, or other processes, typically include one or more process controllers that are accessible via an analog, digital, or combined analog / digital bus. are communicatively coupled to each other, to at least one host computer or operator workstation and to one or more field devices. Field devices can be, for example, valves, valve positioners, switches, and transmitters (such as temperature, pressure, and flow rate sensors) that function in processes such as op...

AI Technical Summary

Problems solved by technology

However, this technique is computationally expensive since it performs a matrix transformation and cannot be used in some cases such as MPC implemented as a function block in a process controller

Equally important, some combinations of inputs and outputs of the resulting controller may lead to ill-conditioned controllers, which lead to unacceptable operation

Although it is possible to build controller configurations offline to verify and improve control tuning, this task is too burdensome for online operation and is not practical to implement at the controller level

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