Home › Forums › FOMCON toolbox: Support forum › Fractional PID Controller Design
- This topic has 51 replies, 2 voices, and was last updated 9 years, 8 months ago by
Aleksei.
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March 7, 2013 at 20:21 #513
Parinya
GuestHello,
I came across FOMCON toolbox and found that it is very interesting and useful for the control system design. After trying several things, I have the following questions:
1. In order to find the parameters of FOPID and optimization, does the plant to be controlled need to be stable first?
2. When trying to do the optimization of the FOPID, by selecting Noise and disturbance rejection box, the program give an error: ” Undefined function ‘csens’ for input argument of type ‘zpk’ “.
3. Lastly, is there any example of the usage of FOMCON?
Thanks for your time and help.
Parinya
March 8, 2013 at 21:18 #516Aleksei
KeymasterHello, and thank you for your feedback!
1. In order to run the optimization procedure, the plant does not need to be stable per se; however, you will most likely run into problems with unstable plants. Careful initial inspection of unstable systems is advised.
2. Please check that your path is correctly set. Which version of MATLAB are you using? There is a backwards compatibility issue that appeared somewhere between R2010 and R2012 which is related to particular class methods and overloading thereof. This issue may need to be reported via the bug tracker.
3. Yes, there are several upcoming conference papers illustrating the use of the toolbox. Unfortunately, I cannot publish these on the site. I am, however, planning on creating several tutorials covering some basics of using the toolbox. A complete user manual is also planned.
April 9, 2013 at 16:43 #728Parinya
GuestThank you for your answer Aleksei. I’m looking forward for the upcoming development. You did a very good job.
April 17, 2013 at 10:56 #757Samcootte
GuestYou will discover some interesting points in time in this article but I do not know if I see all of them center to heart. There is some validity but I will take hold opinion until I look into it further. Superior article , thanks and we want a lot more! Added to FeedBurner as well
April 26, 2013 at 13:23 #759Yashar
GuestHi, first of all thank you for your great job !!
i have a question : is there any command in FOMCON same az the command ” stepinfo” ?
thank you so much.
April 26, 2013 at 14:09 #761Aleksei
KeymasterHi,
No, there is no overloading function `stepinfo()` for the fractional-order transfer function object yet, but the CST version can be employed as well. Consider an example:loadsets [y,t]=step(oustapp(G2)); stepinfo(y,t,1)
Here, I first load the example systems provided with FOMCON, then approximate a fractional-order system G2 by an integer-order one in the form of a refined Oustaloup recursive filter and obtain y and t vectors explicitly.
Note, however, that approximation parameters for a particular system need to be thoroughly selected to obtain a feasible result.
April 30, 2013 at 17:43 #768dhar
GuestDear Aleksei,
Im trying to run the fpid_optim .fig file fpid_optim .m file, which is used to find out the fractional order PID parameters through FPID Optimum tool. but wen im trying to fix the gain parameters in the table it getting the errors listed belowAttempt to reference field of non-structure array.
Error in fpid_optim>menuFix_Callback (line 957)
set(handles.txtLam, ‘Enable’, expEnable);Error in gui_mainfcn (line 96)
feval(varargin{:});Error in fpid_optim (line 24)
gui_mainfcn(gui_State, varargin{:});Error in
@(hObject,eventdata)fpid_optim(‘menuFix_Callback’,hObject,eventdata,guidata(hObject))Error while evaluating uicontrol Callback.
if there is any example program regarding this problem please send me….
thank you in advance………..April 30, 2013 at 20:52 #769Aleksei
KeymasterType
fpid_optim
in MATLAB command line to launch the tool. If you are still getting errors, please elaborate, i.e. provide the exact steps needed to reproduce the error.May 1, 2013 at 07:38 #770muralidhar
GuestDear Aleksei,
hi, Regarding FPID Optimum tool,if i entering lti plant model as a transfer function model in FPID Optimum tool its showing the below errorsUndefined function or variable “Z_p”.
Error in fpid_optimfun (line 105)
e = 1 – step(feedback(Z_p*Z_c,1), t);Error in fpid_optimize>@(x)fpid_optimfun(x,G,opt) (line 267)
x_opt = optimize(@(x) fpid_optimfun(x,G,opt), …Error in optimize/funfncP (line 613)
obj_fval = funfcn(x_new, varargin{:});Error in optimize>@(x)funfncP(X(x),varargin{:}) (line 393)
funfncT = @(x) funfncP(X(x), varargin{:});is these tool is not supported to transfer function model(instead if i entering fotf model im getting the results)……please refer to it
Thanks in advanceMay 1, 2013 at 11:28 #771Aleksei
KeymasterAny proper LTI model can be used: (fractional-order) transfer function, zero-pole-gain, or state-space.
May 1, 2013 at 12:00 #772mural
Guestim doing the same procedure as you replied to me ,sorry to say this sir,but for fractional order transfer function as plant model it is working fine but when it comes to integer order transfer function as plant model its showing the above mentioned error……..
June 5, 2013 at 06:47 #785Pritesh
GuestHi Aleksei,
I am using FOMCON from last couple of months. It is really nice toolbox for beginners in fractional calculus to understand and implement.
Some Questions:
1. How do we select minimum and maximum frequency and order of Approximation?
2. Sometime, Frictional PID Optimization gives good result but When I implement same result into simulation, it gives error.
Could you please help me in above issues?
June 5, 2013 at 08:02 #786Aleksei
KeymasterHello Pritesh,
1. The choice of approximation parameters ultimately depends on the application. The wider the frequency range and order, the more accurate the results. But it may become difficult to implement the system (or controller) as, e.g., an active filter or a digital IIR filter.
2. Could you provide an example?
August 7, 2013 at 07:19 #806Pritesh
GuestHi,
Do we have a function for root locus in FOMCON?
If yes, could you please give some small example?
Thanking You,
Pritesh
August 7, 2013 at 08:35 #808Aleksei
KeymasterHello Pritesh,
This feature is not implemented yet.
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