Hi Piyalis,

In this application the Extended State Observer tool is used to estimate state variables. However, the controller can be of different types such on Linear quadratic regulator (LQR),  Adaptive Sliding Mode Controller(ASMC) or Adaptive Super Twisting Algorithm (ASTA). 

If necessary I can provide references for design a controller for a twin rotor MIMO systems

Best regards

Thank you Prof Mourad.

If you give me an example then it will be much appreciated by me. I am doing a problem on the applications of ESO in MIMO systems. Please send me the example.

Reg

hi Piyali,

Here are some references for design a controller for a twin rotor MIMO systems

-Attitude observer-based robust control for a twin rotor system

www.kybernetika.cz/content/2013/5/809/paper.pdf

-Optimal Control of Twin Rotor MIMO System Using LQR Technique

www.springer.com/cda/content/.../9788132222040-c2.pdf?...0...

-OBSERVER-BASED ATTITUDE CONTROL FOR A TWO-ROTOR ...

lib.physcon.ru/file?id=0a37325c7242

-Adaptive second order sliding mode control strategies ... - IIT Guwahati

www.iitg.ernet.in/engfac/chitra/notes/thesis.pdf

Best regards

It has been proven since 1980 that if your system has more inputs than outputs (p > m), or is non-minimum-phase(most systems are if p = m and order n - m > 2), or rank(CB) < p for your system model (A,B,C), then the critical robustness property of your state feedback control (SFC) CANNOT be fully realized (unless your SFC is not designed for a good control but instead only for being fully realized). The existing approximate solution to this critical problem (called asymptotic LTR) is far from satisfactory either because it requires very high observer gain.

If your system unfortunately belongs to the above category (almost all non-trivial systems do), then to fully realize that critical property, you should use only partial state observer and partial SFC. That means you should design your SFC based on your observer parameters and parameter C, and you should abandon the state observer and the separation principle (design SFC and state observer separately) which has been followed by everyone for over half of a century. The complete design procedure is developed and is valid for all systems either satisfy p < m or has at least one stable transmission zero (or for almost all systems, hopefully including your system). I will stop here for details. You can find this new design in my publications. I would suggest "Observer Design -- A Survey" of 2015.

The key for an observer to realize the robust property is to eliminate its gain on system input. My result above can also be used to design a least square gain (instead of zero gain), This approximate solution is much more effective and satisfactory than asymptotic LTR, but approximations have no guarantee.

Finally, please do not be discouraged for two reasons. 1) My design is very simple and much much simpler than the loop transfer function based designs, and SFC (even partial SFC) is much much more effective than other forms of control; 2) A challenging design also means an opportunity for advancement -- you may achieve a good design not achieved by anyone before including MIT professors!

Thank you Prof. Tsui for your valuable advice, I am going through with the input verification methods and also with your design, if I have some queries again I'll post a question.

Reg

Piyali 

It will be my pleasure to see you succeed in your design project. Please feel free to contact me any time.

Please refer to this article:

https://www.researchgate.net/publication/318726178_An_Improved_Active_Disturbance_Rejection_Control_for_a_Differential_Drive_Mobile_Robot_with_Mismatched_Disturbances_and_Uncertainties

Conference Paper An Improved Active Disturbance Rejection Control for a Diffe...

yes you can do it using Linear ESO and Nonlinear ESO.

I have already solved the problem before some time but one more problem arieses with that which is the weighted matrix Q is not properly designed, I have considered random matrices for Q. Is there any proper method to find Q in MIMO system as I have tried Brayon's method, Algebric approach but nothing is mentioned about MIMO system. Please let me know about any other method.