09-19-2011 06:10 PM
Hi
Iam using a simple quadrature encoder...I need to know how should I model it in the control loop.
Thanks
Solved! Go to Solution.
09-20-2011 12:04 PM
Hello SK0480
Thank you very much for getting in touch with us! The quadrature encoder is simply a way of determining the position/speed/acceleration of your motor through feedback. It should have negligible effects on the system dynamics.
Are you simply looking to convert the encoder feedback to something meaningful? If so, all you would need to do in your feedback loop is add a compatibility equation for your sensor converting the number of encoder counts to the number of revolutions.
How many encoder counts are there per revolution? You would simply want to include an equation in your code to convert the encoder counts to motor revolutions in order to implement your feedback system.
09-20-2011 01:15 PM
Hi
The resolution of the encoder is 16 pulses per revolution....so i want to convert the counts to the revolution what would be the equation for it
09-20-2011 03:04 PM - edited 09-20-2011 03:05 PM
Hello SK0480
Thank you for this information. To find the number of revolutions for a given number of pulses, simply divide the number of pulses by 16.
For a more detailed explanation:
If you know that the encoder is 16 pulses per revolution then we also know how many revolutions per pulse we have. To obtain this value, we simply take the inverse value of the pulses per revolution to find the number of revolutions per pulse.
In short, Number of Revolutions = (Number of Pulses) / 16 = (1/16) x Number of Pulses = (0.0625 x Number of Pulses)
So, if you have convert counts to revolutions, multiply the number of pulses by 0.0625 or divide by 16.
I have included a document that illustrates this step by step but I do not mean to make this situation overly complicated.
This concept will be very important for your success so please let me know if I can provide any further clarification.
09-22-2011 04:46 PM
Hello
Thanks for sending me the compatibilty equations.
Ok now the quadrature encoder iam using has a resolution of 16 pulse /revolution as I mentioned earlier...what iam getting out of this encoder is the angle that motor has rotated..so what would be proper compatibility equation.
09-23-2011 09:21 AM
If the feedback you are receiving is the rotation angle and you want to know how many times the motor has turned, just divide the fed back rotation angle by 2*pi radians or 360 degrees. One rotation is defined as 2*pi radians or 360 degrees. Please let me know if this is clear, I will be happy to explain it further as you require.
09-24-2011 03:51 AM
09-26-2011 08:47 AM
Hello SK0480
If you are building a block diagram, you won't have to include your sensor conversions for the feedback. What I am most concerned about is that you may accidentally consider this conversion factor as a gain. You will receive different system dynamics if you do this.
09-26-2011 02:40 PM
so are you saying to not include anything in the feeback
09-26-2011 03:03 PM
Hello SK0480
So that I can best assist you, what system exactly are you trying to control and what is your input/ouput signal that you are dealing with? Do you want to upload your current model for my reference? Thank you very much for your response!