hasan asked . 2022-03-11

Closed Loop system identification toolbox

Hi all,

Is there any MATLAB Toolbox available for Closed Loop System Identification because MATLAB's current system identification toolkit is for identification of open loop systems?

I already knew one tool named CLOSID but it is not as flexible as MATLAB's sys ID toolkit and i am facing some problems in using it.

Is there anyway of using MATLAB's system identification toolkit for CLOSED LOOP SYSTEMS?

closed , Control Systems , System Identification Toolbox , Data Preparation , Data Preparation B

Expert Answer

Prashant Kumar answered . 2024-12-21 17:30:46

A model in System Identification Toolbox represents the equation y = Gu + He where G is the transfer function between y and u and H is the transfer function between y and e. G is called the "measured" component and H the "noise component" of the overall transfer function between y and [u, e].

In state space case, the equation is:

x(k+1) = A x(k) + B u(k) + K e(k)
  y(k) = C x(k) + D u(k) + e(k)

H in this case is:

x(k+1) = A x(k) + K e(k)
  yh(k) = C x(k) + e(k)

When you estimate a state space model using PEM, you estimate the values of one or more of A, B, C, D and K. In order to have a nontrivial noise component in your model, make sure that K is not fixed at zero. You do this by using "DisturbanceModel"/'estimate' PV pair in the estimation command or by setting the DisturbanceModel property of an existing IDSS model to 'estimate':

model = pem(data, NX, 'dist', 'estimate')
model2 = idss(drss(NX)) % or some other template you created using IDSS command
model2.DisturbanceMOdel = 'estimate'
model2 = pem(data, model2, 'focus', 'prediction')

Now, the claim is that estimating K along with A, B, C, D helps identify the plant even though it was operating under closed loop. Why this is the case is best answered in the reference I mentioned before. Here is a simple description: if you are measuring signals right at the I/O ports of a plant, you are indeed measuring the effect of changes in input at the plant's output. However the input signal contains the portion of the past output (because of feedback). This by itself is not a problem. But you are not only feeding back the previous outputs but also any disturbances that might have affected those previous output values. This disturbance is thus correlated with the system inputs. Adding a sufficiently flexible "H" helps you separate out the effect of disturbances on the plant output.

In other model structures, H can be suitably (even independently) defined. For example, in a Box Jenkins polynomial model, you have separate transfer functions for H and G whose orders your can pick independently (see IDPOLY, BJ; see also ARMAX).

There are persistence of excitation and other requirements for getting good results from closed loop data. Perhaps a better reference than I mentioned before is:

   System Identification — Theory For the User, Lennart Ljung, Section 13.4-13.5, 2nd ed, PTR Prentice Hall, Upper Saddle River, N.J., 1999.

Not satisfied with the answer ?? ASK NOW

Recent Matlab Projects

Classification of Covid and Non-Covid Lungs CT-Scan using Deep Learning with MATLAB

Matlab simulation on Wind Energy system

Frequently Asked Questions

MATLAB offers tools for real-time AI applications, including Simulink for modeling and simulation. It can be used for developing algorithms and control systems for autonomous vehicles, robots, and other real-time AI systems.

MATLAB Online™ provides access to MATLAB® from your web browser. With MATLAB Online, your files are stored on MATLAB Drive™ and are available wherever you go. MATLAB Drive Connector synchronizes your files between your computers and MATLAB Online, providing offline access and eliminating the need to manually upload or download files. You can also run your files from the convenience of your smartphone or tablet by connecting to MathWorks® Cloud through the MATLAB Mobile™ app.

Yes, MATLAB provides tools and frameworks for deep learning, including the Deep Learning Toolbox. You can use MATLAB for tasks like building and training neural networks, image classification, and natural language processing.

MATLAB and Python are both popular choices for AI development. MATLAB is known for its ease of use in mathematical computations and its extensive toolbox for AI and machine learning. Python, on the other hand, has a vast ecosystem of libraries like TensorFlow and PyTorch. The choice depends on your preferences and project requirements.

You can find support, discussion forums, and a community of MATLAB users on the MATLAB website, Matlansolutions forums, and other AI-related online communities. Remember that MATLAB's capabilities in AI and machine learning continue to evolve, so staying updated with the latest features and resources is essential for effective AI development using MATLAB.

Without any hesitation the answer to this question is NO. The service we offer is 100% legal, legitimate and won't make you a cheater. Read and discover exactly what an essay writing service is and how when used correctly, is a valuable teaching aid and no more akin to cheating than a tutor's 'model essay' or the many published essay guides available from your local book shop. You should use the work as a reference and should not hand over the exact copy of it.

Matlabsolutions.com provides guaranteed satisfaction with a commitment to complete the work within time. Combined with our meticulous work ethics and extensive domain experience, We are the ideal partner for all your homework/assignment needs. We pledge to provide 24*7 support to dissolve all your academic doubts. We are composed of 300+ esteemed Matlab and other experts who have been empanelled after extensive research and quality check.

Matlabsolutions.com provides undivided attention to each Matlab assignment order with a methodical approach to solution. Our network span is not restricted to US, UK and Australia rather extends to countries like Singapore, Canada and UAE. Our Matlab assignment help services include Image Processing Assignments, Electrical Engineering Assignments, Matlab homework help, Matlab Research Paper help, Matlab Simulink help. Get your work done at the best price in industry.