How to use Signal Logger/SysID

COLTech9059 · January 11, 2025, 11:04pm

Hello! This is the programming team for FRC team 9059 speaking.

After building our swerve drive base and using Phoenix Tuner X’s swerve project generator, we are now trying to tune our PID gains.

We’ve found that SysID/Signal Logger will likely be our way to go, but are confused on how to operate it and send data to it.

We have attempted to create a function to send the data (quasistatic and dynamic), but it causes the motors to roughly interact with the gears in the module.

Help would be appreciated!

myer · January 12, 2025, 2:51am

Phoenix Tuner X’s swerve project generator automatically creates SysId routines for drive and steer:

github.com

RambotsTeam1350/REEFSCAPE-2025/blob/af10a15daa511614ae1ba7911cd65d271a1d3fa8/src/main/java/frc/robot/subsystems/drivetrain/CommandSwerveDrivetrainSubsystem.java#L65


      
                                                                                                                           // deadband
                  .withDriveRequestType(DriveRequestType.OpenLoopVoltage); // Use open-loop control for drive motors
          public final SwerveRequest.SwerveDriveBrake brakeRequest = new SwerveRequest.SwerveDriveBrake();
          public final SwerveRequest.PointWheelsAt pointRequest = new SwerveRequest.PointWheelsAt();
          public final Telemetry logger = new Telemetry(TunerConstants.MaxSpeed);
          
          /*
           * SysId routine for characterizing translation. This is used to find PID gains
           * for the drive motors.
           */
          private final SysIdRoutine m_sysIdRoutineTranslation = new SysIdRoutine(
                  new SysIdRoutine.Config(
                          null, // Use default ramp rate (1 V/s)
                          Volts.of(4), // Reduce dynamic step voltage to 4 V to prevent brownout
                          null, // Use default timeout (10 s)
                          // Log state with SignalLogger class
                          state -> SignalLogger.writeString("SysIdTranslation_State", state.toString())),
                  new SysIdRoutine.Mechanism(
                          output -> setControl(m_translationCharacterization.withVolts(output)),
                          null,
                          this));

github.com

RambotsTeam1350/REEFSCAPE-2025/blob/af10a15daa511614ae1ba7911cd65d271a1d3fa8/src/main/java/frc/robot/RobotContainer.java#L64


      
                          // negative X (left)
                          ));
          
          driverController.a().whileTrue(drivetrain.applyRequest(() -> drivetrain.brakeRequest));
          driverController.b().whileTrue(drivetrain.applyRequest(
                  () -> drivetrain.pointRequest.withModuleDirection(
                          new Rotation2d(-driverController.getLeftY(), -driverController.getLeftX()))));
          
          // Run SysId routines when holding back/start and X/Y.
          // Note that each routine should be run exactly once in a single log.
          driverController.back().and(driverController.y()).whileTrue(drivetrain.sysIdDynamic(Direction.kForward));
          driverController.back().and(driverController.x()).whileTrue(drivetrain.sysIdDynamic(Direction.kReverse));
          driverController.start().and(driverController.y()).whileTrue(drivetrain.sysIdQuasistatic(Direction.kForward));
          driverController.start().and(driverController.x()).whileTrue(drivetrain.sysIdQuasistatic(Direction.kReverse));
          
          // reset the field-centric heading on left bumper press
          driverController.leftBumper().onTrue(drivetrain.runOnce(() -> drivetrain.seedFieldCentric()));
          
          driverController.x().whileTrue(new FollowAprilTag(drivetrain, limelight));
          driverController.povUp().whileTrue(
                  drivetrain.applyRequest(() -> drivetrain.driveRequest.withVelocityX(TunerConstants.MaxSpeed * 0.25)));

Simply use the defined controller bindings to run the tests. Run the four drive tests and the four steer tests in two different log files. Make sure each log file contains ONLY the four respective tests (redeploy your code right before you run the tests). The tests will be in /home/lvuser/logs if there is no flash drive on your roboRIO or simply in the logs folder of the flash drive if there is. Once you have obtained the correct log file (file extension .hoot), convert it to a .wpilog log. If you have trouble using Phoenix Tuner X to do so, refer to this thread: Can't Convert .hoot Log to .wpilog - #18 by daltzsmith