Embedded Files
Pulse Width Modulation
Pulse Width Modulation
Use of PWM signals for DC Motors:
Use of PWM signals for DC Motors:
PWM is a type of digital signal that helps control motor speed by rapidly switching the power on and off instead of providing analog voltages (https://www.circuitbread.com/ee-faq/what-is-a-pwm-signal). This method allows for an efficient approach to controlling a dc motor's speed and torque by adjusting the duty cycle. The duty cycle describes the percentage the signal is "on" over a period of time. In matlab we used the duty cycle to test different positions of the motor (encoder values) and see the resulting effect on the duty cycle phase.
Testing 3 PWMcmdRaw values:
Testing 3 PWMcmdRaw values:
Loops
Loops
Use of the "For Loop":
Use of the "For Loop":
The for loop ensures that the code will run and measure the motor speed for each value inside the PWMcmndRaw file, and it will run as long as there are values inside the PWMcmdRaw (see below).
Measured Speed vs PWM Duty Cycle
Measured Speed vs PWM Duty Cycle
Raw Data:
Raw Data:
Relationship between PWM duty cycle and motor speed: From -1 to -0.5, the motor speed increases smoothly, and from -0.5 to 0, it increases its speed rate. At a PWM command of 0 to 0.2, the speed remains stable, indicating a headband. From 0.2 forward, the speed begins to increase again as it reaches a high pwm command. At PWM commarnds of -1 and 1, the speed slows down barely and doesn't increase as much.
Relationship between PWM duty cycle and motor speed: From -1 to -0.5, the motor speed increases smoothly, and from -0.5 to 0, it increases its speed rate. At a PWM command of 0 to 0.2, the speed remains stable, indicating a headband. From 0.2 forward, the speed begins to increase again as it reaches a high pwm command. At PWM commarnds of -1 and 1, the speed slows down barely and doesn't increase as much.
Identifying Functions within the Raw Data Graph:
Identifying Functions within the Raw Data Graph:
This graph correctly represents a function as it follows the vertical line rule- meaning for each x input, there is only one output (y value).
This graph correctly represents a function as it follows the vertical line rule- meaning for each x input, there is only one output (y value).
Processed Data:
Processed Data:
Modifying My MATLAB Code to Create a Function for Motor Speed as a Function of PWM: The two data plots showcase the steps taken to create a function from the raw data. The blue represents the raw data, and the orange represents the processed data as a function. To get there, the raw data is processed in section four, where it creates indexes of the raw motor speed value, filters through the values so is only one PWM command corresponding to each speed (filters out non-monotonic values), and detects zeros or non-increasing speed values. Section five then plots the filtered and processed raw data as a function.
Modifying My MATLAB Code to Create a Function for Motor Speed as a Function of PWM: The two data plots showcase the steps taken to create a function from the raw data. The blue represents the raw data, and the orange represents the processed data as a function. To get there, the raw data is processed in section four, where it creates indexes of the raw motor speed value, filters through the values so is only one PWM command corresponding to each speed (filters out non-monotonic values), and detects zeros or non-increasing speed values. Section five then plots the filtered and processed raw data as a function.
Raw and post-processed speed vs PWM duty cycle data.
Raw and post-processed speed vs PWM duty cycle data.
Final Matlab Code:
Final Matlab Code:
untitled2.pdfFunctions
Functions
Advantages of creating a function:
Advantages of creating a function:
This method helps simplify tests so the user can change the input pwm commands while maintaining an organized code workspace. It makes it easier to save different sets of data so the user can specify which ones to run in their main matlab file.
This method helps simplify tests so the user can change the input pwm commands while maintaining an organized code workspace. It makes it easier to save different sets of data so the user can specify which ones to run in their main matlab file.
MATLAB Code with Functions
MATLAB Code with Functions
update matlab code with functions.pdfmyMotorFunction.pdfPage updated
Google Sites
Report abuse