We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 05 June 2012
There are many advanced strategies in classical control systems. Only a limited selection of examples is presented in this chapter. We start with cascade control, which is a simple introduction to a multiloop, but essentially SISO, system. We continue with feedforward and ratio control. The idea behind ratio control is simple, and it applies quite well to the furnace problem that is used as an illustration. Finally, a multiple-input multiple-output (MIMO) system is addressed with a simple blending problem as illustration, and the problem is used to look into issues of interaction and decoupling. These techniques build on what we have learned in classical control theories.
What Are We Up to?
Applying classical controller analysis to cascade control, feedforward control, feedforward–feedback control, ratio control, and the Smith predictor for time-delay compensation
Analyzing a MIMO system with relative gain array and assessing the pairing of manipulated and controlled variables
Attempting to decouple and eliminate the interactions in a two-input two-output system
Cascade Control
A common design found in process engineering is cascade control. This is a strategy that allows us to handle load changes more effectively with respect to the manipulated variable.
To illustrate the idea, we consider the temperature control of a gas furnace, which is used to heat up a cold process stream. The fuel-gas flow rate is the manipulated variable, and its flow is subject to fluctuations that are due to upstream pressure variations.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.
