Motion Profiling & CSV Files Help

Technical Java
1

I successfully generated .csv files using the Motion Profile Generator tool found here.

How do I use the values in the .csv files in my autonomous code?

2

You have to find a way to send the files over to your roboRIO (ssh works), and then read them from your code.

3

OK, but how do I incorporate the values into code? Do I use them in a PID loop? And how would I ensure that the robot is following the waypoints?

4

You can implement them by using something similar to the code here but instead of an array of waypoints read from the files like this


  File leftFile = new File("/path/to/left/trajectory/on/roborio.csv");
  File rightFile = new File("/path/to/right/trajectoryon/roborio.csv");
  Trajectory leftTrajectory = Pathfinder.readFromCSV(leftFile);
  Trajectory rightTrajectory = Pathfinder.readFromCSV(rightFile);
5

In the installation instructions, it says:

Copy the Pathfinder-Java jar file to <user home>/wpilib/user/lib. In your project, open the build.properties file and uncomment the line #userLibs=${user.home}/wpilib/user/lib (remove the # from the front to uncomment).

Do I copy the Pathfinder-Java jar file from \Pathfinder-master\Pathfinder-Java\build\libs\Pathfinder-Java-1.8.jar? Or from somewhere else? - this wasn’t specified.

Also I do not have a build.properties file in my WPILib Project (VS Code), so I cannot uncomment that line that is mentioned. Is it safe to skip this step?

6

Those instructions are intended for the eclipse plugins (i.e. last year). If you’re using GradleRIO, I’m fairly sure that you can just add the following line in the dependencies {} section of your build.gradle:


compile pathfinder()
7

The wiki has detailed step-by-step instructions that go over implementing the follower in your code.

8

Thanks everyone for your help.

One last question, how do I calculate the max velocity, max acceleration and jerk of the robot? Is it something I have to test and figure out or can I find it based on my drivetrain components?

9

Don’t worry too much about jerk.

Read the drivetrain characterization whitepaper in my sig for information that will help with velocity and acceleration.