Objective

Get the motors running on the robot with our motor controller, simulate in a virtual environment



Materials Used



Procedure

4A: Open Loop Control (Real)


First, I connected the Artemis board to the supplied motor driver board using a Qwiic cable

Next, I loaded up the software example "Example1_wire" to scan the i2c bus for a component, and found it at 0x5D.
i2c
Next, I took apart the RC car by unscrewing the top, disconnecting the control PCB, and cutting all the leads off that.

I stripped the DC motor connector wires and screwed them into the motor controller terminals, and did the same for the battery connector. I did have to do some "refactoring" of the hot glue with a heat gun so the DC motor cables didn't rip off.
connections
Next, I plugged the battery in, installed the SCMD library in Arduino, and pulled up the MotorTest script. I had to change the code a bit, first by adding the correct i2c address as found above, and then by setting i=2 for the number of motors. They both ran from this script as shown below

The next step was to ensure both wheels were spinning at approximately the same speed and get the robot moving independently, in open-loop form, in a straight line. I did this by first setting the two motors to the same forward linear speed and seeing the difference in how fast the two motors spun. Actually, they ended up spinning at pretty much the same speed when I had them on the floor, so I didn't need to adjust them. Here they are set to level "50" out of 255, which was the lowest I could go and get feedback from them. As you can see, the robot travels in a straight line for quite some time. 



        myMotorDriver.setDrive( 1, 1, 50); 
        myMotorDriver.setDrive( 0, 0, 50);

Next, for fun, I decided to see if the robot would respond in open-loop fashion only when it heard my (sad) whistle by combining elements of Lab1. I mainly just ported over the motor code into my lab1 code, with some fiddling with libraries. I was getting some errors about library mismatches, so I selectively commented out libraries until it stopped throwing errors (arduino.h was the culprit) 

      Serial.printf("Loudest frequency: %d         \n", ui32LoudestFrequency);
      if (ui32LoudestFrequency > 4000) {
        digitalWrite(LED_BUILTIN, HIGH);
        myMotorDriver.setDrive( 1, 1, 70); 
        myMotorDriver.setDrive( 0, 0, 70); 
        //delay(250);
      }
      else { 
        digitalWrite(LED_BUILTIN, LOW);
        myMotorDriver.setDrive( 1, 1, 0); 
        myMotorDriver.setDrive( 0, 0, 0); 
        //delay(250);
      }



And some turns for fun!

4A: Open Loop Control (Simulated)


Next, I set up the lab4 simulator the same way I did in lab 3, and started up jupyter labs in a terminal, which brought me to the lab4 jupyter notebook.
Reading through, I saw it gave examples of both how to get the position of the robot and how to change the linear and angular velocity. At first I was going to use the known position to calculate when I should turn in a square, but open loop control by definition does not use feedback like that
Therefore, I decided to instead play around with different values for linear/angular velocity and sleep times to make the robot move in a straight line, stop, turn ~90 degrees, and repeat four times. Here's the code as well as a video of that running in the simulation
connections