Just a little revision: at 6:42 you've settled a delta T of 10°F instead of the real value of 20°F about the jacket temperature. Due to this, you've calculated a wrong value of Kp (2 instead of 1) and a wrong value of Kc=P (0.5 instead of 1) and I (1 instead of 2). In this way you can explain why you need a more aggressive Pvalue after the first simulation. Anyway, I would like to thank for the great support you provide for my engineering formation, good job.
Yes, a derivative part could help with the run-away reaction. It is a very challenging nonlinear control problem, similar to what is encountered with exothermic industrial processes such as polymers. Those industrial processes typically have emergency cooling or flaring systems to shutdown safely. Here is more information on that problem but in Python: apmonitor.com/pdc/index.php/Main/StirredReactor
Hi. I am new to control systems. Every video i look your output is already giving you steady state output. Whereas in my case my output goes exponentionally (unstable system). That is one of my objectives - to use a controller and stablize my output with the reference input. So determining time constant and the rest are impossible because it never gets to a steady state. I have managed to tune a controller by trail and error method. Any guidance will be much appreciate. Thanks
For unstable systems, you typically need to create a model of some type (first principles, linear transfer function, etc) and then perform an analysis to make the system stable such as with a root locus plot, bode plot, or just simulation of the control. Here is more info on a stability analysis: apmonitor.com/pdc/index.php/Main/StabilityAnalysis You may also want to look at Model Predictive Control. Here is control of an unstable system: apmonitor.com/do/index.php/Main/InvertedPendulum
Thanks for the tutorial .How did you model your CSTR at first place? I am dealing with a complex none-linear system and I am not sure how I can model it. Any advice for me?
Here is a tutorial to get started with complex nonlinear systems: th-cam.com/video/QKhy1JsdiUo/w-d-xo.html You can also explore the dynamic optimization course at apmonitor.com/do The introduction sections have information on modeling.
Thank you for the tutorial. I am learning the basics about control systems, can you please tell me how to get the transfer functions (relating the inputs to outputs) from this process? - Thank you in advance
+Kenny Herrera, here is some help with the modeling: apmonitor.com/che436/index.php/Main/CaseStudyCSTR You may also be interested in the derivation. Here is some help with linearization: apmonitor.com/pdc/index.php/Main/ModelLinearization and transfer functions: apmonitor.com/pdc/index.php/Main/TransferFunctions
Dear sir i use PI to conrol error in frequance and i wish to optimize the value of Kp and Ki to reduce the error any advice for optimization in simulink for Kp and Ki values
+maatheking2010 There are good tuning rules such as IMC and ITAE to help you get good starting values of Kp and Ki terms. Please see apmonitor.com/che436/uploads/Main/PPC_Textbook.pdf (Appendix D, pg 285). Another option is to use Model Predictive Control if a PID controller is not sufficient. There is additional information on this approach at apmonitor.com/do.
Just a little revision: at 6:42 you've settled a delta T of 10°F instead of the real value of 20°F about the jacket temperature. Due to this, you've calculated a wrong value of Kp (2 instead of 1) and a wrong value of Kc=P (0.5 instead of 1) and I (1 instead of 2). In this way you can explain why you need a more aggressive Pvalue after the first simulation.
Anyway, I would like to thank for the great support you provide for my engineering formation, good job.
Andrea Canali Great catch, Andrea! You are correct.
Professor Hedengren, do you have an explanation (video) about how to design a controller (applied to biosystems)?
Here is one example: apmonitor.com/pdc/index.php/Main/DiabeticBloodGlucose
@Apmonitor.com what if you added a derivative part, wouldn't it help with the spikes ?
Yes, a derivative part could help with the run-away reaction. It is a very challenging nonlinear control problem, similar to what is encountered with exothermic industrial processes such as polymers. Those industrial processes typically have emergency cooling or flaring systems to shutdown safely. Here is more information on that problem but in Python: apmonitor.com/pdc/index.php/Main/StirredReactor
the manipulated variable is the jacket temperature. it is the same as changing the inlet flow of the coolant?
They are not the same but they are related. The flow is the inner loop for the jacket temperature control.
Do you have PID non-linear in Excel?
Yes, please see this page: apmonitor.com/che436/index.php/Main/CaseStudyCSTR There is an Excel worksheet for the CSTR example.
Hi.
I am new to control systems. Every video i look your output is already giving you steady state output. Whereas in my case my output goes exponentionally (unstable system). That is one of my objectives - to use a controller and stablize my output with the reference input. So determining time constant and the rest are impossible because it never gets to a steady state. I have managed to tune a controller by trail and error method. Any guidance will be much appreciate.
Thanks
For unstable systems, you typically need to create a model of some type (first principles, linear transfer function, etc) and then perform an analysis to make the system stable such as with a root locus plot, bode plot, or just simulation of the control. Here is more info on a stability analysis: apmonitor.com/pdc/index.php/Main/StabilityAnalysis You may also want to look at Model Predictive Control. Here is control of an unstable system: apmonitor.com/do/index.php/Main/InvertedPendulum
thank you in advance ----AND THANK YOU FOR YOUR GREAT VIDEOS
Thanks for the tutorial .How did you model your CSTR at first place? I am dealing with a complex none-linear system and I am not sure how I can model it. Any advice for me?
Here is a tutorial to get started with complex nonlinear systems: th-cam.com/video/QKhy1JsdiUo/w-d-xo.html You can also explore the dynamic optimization course at apmonitor.com/do The introduction sections have information on modeling.
Thank you! I am actually watching the course lectures.
Thank you for the tutorial. I am learning the basics about control systems, can you please tell me how to get the transfer functions (relating the inputs to outputs) from this process? - Thank you in advance
+Kenny Herrera, here is some help with the modeling: apmonitor.com/che436/index.php/Main/CaseStudyCSTR You may also be interested in the derivation. Here is some help with linearization: apmonitor.com/pdc/index.php/Main/ModelLinearization and transfer functions: apmonitor.com/pdc/index.php/Main/TransferFunctions
Dear sir i use PI to conrol error in frequance and i wish to optimize the value of Kp and Ki to reduce the error
any advice for optimization in simulink for Kp and Ki values
+maatheking2010 There are good tuning rules such as IMC and ITAE to help you get good starting values of Kp and Ki terms. Please see apmonitor.com/che436/uploads/Main/PPC_Textbook.pdf (Appendix D, pg 285). Another option is to use Model Predictive Control if a PID controller is not sufficient. There is additional information on this approach at apmonitor.com/do.
+APMonitor.com many thanks for your grateful help