Process Control Challenge

Process Control Challenge Problems

updated 2021-10-04

We use simulators to test many aspects of control and automation algorithms.  Desirably, the challenge problems should be simple to understand and implement, as well, they should represent issues characteristic of the applications.  Control in the chemical process industries (CPI) has a confluence of difficulties that are different from the mechatronic test cases or the deterministic ODEs that characterize many investigations.  This article r3eda Process Control Challenge Problems 2018-11-15 discusses such issues and how to assess controller performance for the CPI.

This link Hot & Cold Mixing Process Simulator Description 2018-09-20 describes a hot and cold water mixing process that I feel is a good test case.  It has two controlled variables (total flow and mixed fluid temperature) and two manipulated variables (signals to the hot and cold valves).  It is nonlinear and interactive, subject to constraints, and the best pairing changes with temperature setpoint.  It currently has two control options SISO PIDs and a simple model based controller.  It is an excellent test case to explore SISO pairing, ratio, decouplers, gain scheduling, and constraint handling.  And, this link Hot and Cold Mixing 2018-09-17 provides access to my water mixing simulator with user options to use either PID or a model-based controller.  Of course, you can include your own controller.

This link pH Modeling and Simulator Description 2021-10-02 describes a pH neutralization process that I feel is a good test case.  It also provides user directions for the simulator (accessed by the link below).  It has two controlled variables, in-tank pH and tank level, and two manipulated variables, caustic inflow and discharge rate.  If the pH is out of discharge limits, then the tank discharge is stopped, and inflow accumulates until pH is back under control.  Then discharge control seeks to return tank contents to the set point level.  It is a nonlinear and non-stationary process with an override, and may be very applicable algorithms seeking to manage these issues through gain scheduling, nonlinear control, or adaptive control.   This link pH Process Simulator w Heuristic Control 2021-10-02 provides access to my pH neutralization simulator.  The current controller is a very simple set of heuristic rules as a placeholder for you to add a better control algorithm.

This simulator r3eda PMBC Car Speed Control LF to Solve for u implicit 2017-04-23 provides a SISO case based on an automobile speed control.  The single controlled variable is vehicle speed, and the single manipulated variable is accelerator pedal position.  Although SISO and with a relatively simple model, the process is nonlinear and subject to environmental disturbances.  User instructions are included with the VBA code.

This heat exchanger simulator uses hot liquid to heat cold liquid in a counter-current heat exchanger.  It is nonlinear, and has a moderately high order.  The deadtime, which is primarily due to transport delay, depends cold fluid flow rate.  It might be useful in demonstrating issues in process control, nonlinear and adaptive algorithms, and cascade.  Here HX Dynamic Simulator w PID 2021-09-09 is access to the simulator.  And here ACC 2022 HX Simulator 2021-09-14 is a link to download the process description.

I anticipate adding a fed-batch process simulator in the near future.