In 7th semester, one of the course I am learning is Feedback Control Systems. Now those who know about Control Systems and my interest for Robotics, would know how much this course interested me. What made this course more interesting was the teacher assigned to our class, Hafiz Muhammad Furqan, and also the project assigned for this course which emphasized on design and critical thinking.
The project required us to extract the transfer function of a DC motor, implement PID controller and perform various analysis on the Plant model.
If you want to learn what is a controller or what is a control system, check out this link: https://www.facstaff.bucknell.edu/mastascu/eControlHTML/Intro/Intro1.html#Introduction
Extracting Transfer Function of DC Motor
The first task was to extract the transfer function of the DC Motor, for this 2 approaches can be used. One is to build the mathematical model of the motor from the known parameters and the second is data driven control. In data driven control, we use the input and output data to design the model of system.
To study more about the mathematical model of the motor visit this link: http://ctms.engin.umich.edu/CTMS/index.php?example=MotorSpeed§ion=SystemModeling
(J) moment of inertia of the rotor
(b) motor viscous friction constant \
(Ke) electromotive force constant
(Kt) motor torque constant
(R) electric resistance
(L) electric inductance
Now in our case we do not have these parameters. The motor we are using is Metal DC Geared Motor w/Encoder - 12V 122RPM 38Kg.cm. Can be found here: https://www.dfrobot.com/product-1210.html?search=122&description=true.
So in our case we use the system identification method. This means we need input and output. For the motor input would be the voltage and output is its angular velocity. In my project I have decided to use System Identification Toolbox from MATLAB. Which requires enough data to make a proper model.
The blog has been broken into different steps, click on the link below to continue reading
Hardware Setup
Data Acquisition
System Identification Toolbox - Transfer Function
Comments
Post a Comment