Need help getting PIDcommand working

[SciborgBotanist6076]

I have been having trouble getting my PIDcommand to work, it just keeps saying that “The constructor PIDCommand(PIDController, IntakeSubSys::getVelocity, double, DoubleConsumer, IntakeSubSys) is undefinedJava(134217858)”. I am trying to follow the example [here]allwpilib/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/gyrodrivecommands/commands/TurnToAngle.java at main · wpilibsuite/allwpilib · GitHub I am not very experienced but I generally know how to figure stuff out as i go, but this one has stumped me. if i could get some help trouble shooting the problem that would be great.

I am not worried about the fact that I don’t need a PID on my intake. It is mainly an exercize so that i know how to do this for other things.

here is my subsystem:

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.

package frc.robot.subsystems;

import edu.wpi.first.wpilibj2.command.SubsystemBase;
import frc.robot.Constants;
import frc.robot.Constants.intakeConstants;
import com.revrobotics.CANSparkMax;
import com.revrobotics.CANSparkLowLevel.MotorType;
import java.util.function.DoubleSupplier;
]
public class IntakeSubSys extends SubsystemBase {


  CANSparkMax nSparkMax = new CANSparkMax(Constants.shooterConstants.kNeoCANPort, MotorType.kBrushless);
  
  /** Creates a new IntakeSubSys. */
  public IntakeSubSys() {
  }

  
  public void runAtSpeed(double velocity) {
    nSparkMax.set(velocity);
  }

  public double getVelocity() {
    //DoubleSupplier sup = () -> nSparkMax.getEncoder().getVelocity();
    return nSparkMax.getEncoder().getVelocity();
  }

}

and here is my PIDcommand:

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.

package frc.robot.commands;

import edu.wpi.first.math.controller.PIDController;
import edu.wpi.first.wpilibj2.command.PIDCommand;
import edu.wpi.first.wpilibj2.command.SubsystemBase;
import frc.robot.Constants.intakeConstants;
import frc.robot.subsystems.IntakeSubSys;

// NOTE:  Consider using this command inline, rather than writing a subclass.  For more
// information, see:
// https://docs.wpilib.org/en/stable/docs/software/commandbased/convenience-features.html
public class IntakeSpeedCMD extends PIDCommand {



  /** Creates a new IntakeSpeedCMD. */
  public IntakeSpeedCMD(double targetSpeed, IntakeSubSys subsystem) {
    super(
        // The controller that the command will use
        new PIDController(intakeConstants.kP, intakeConstants.kI, intakeConstants.kD),

        // This should return the measurement
        IntakeSubSys::getVelocity,

        // This should return the setpoint (can also be a constant)
        targetSpeed,

        // This uses the output
        output -> subsystem.runAtSpeed(output),
        
        subsystem);
        
  }

  // Returns true when the command should end.
  @Override
  public boolean isFinished() {
    return false;
  }
}

[Oblarg]

I’d recommend not using PIDCommand, and instead composing the controller yourself:

Command-based help

No, I’d avoid those and just compose the PIDController inside the Subsystem or Command scope manually, as necessary. Here are some simplified examples: // in subsystem scope // we need a motor and sensor for feedback private final MotorController motor = new FooMotor(); private final Encoder encoder = new Encoder(...); // we could have a PIDController as a field in the subsystem itself... private final PIDController controller = new PIDController(...); // this command captures the subsystem…

[SciborgBotanist6076]

Thanks! I will see if I can do that.

[JDaniel24]

@SciborgBotanist6076

  public double getVelocity() {
    //DoubleSupplier sup = () -> nSparkMax.getEncoder().getVelocity();
    return nSparkMax.getEncoder().getVelocity();
  }

@SciborgBotanist6076

        // This should return the measurement
        IntakeSubSys::getVelocity,

it might be because you are accessing getVelocity in a static way when the method is defined as nonstatic. try

    super(
        // The controller that the command will use
        new PIDController(intakeConstants.kP, intakeConstants.kI, intakeConstants.kD),

        // This should return the measurement
        subsystem::getVelocity, //this line gets changed to call getVelocity in a nonstatic way

        // This should return the setpoint (can also be a constant)
        targetSpeed,

        // This uses the output
        output -> subsystem.runAtSpeed(output),
        
        subsystem);
        
  }```

[SciborgBotanist6076]

Thanks! ran into a few hiccups, but that worked.