How do I use Exponential Profiles?

What are exponential profiles?

Exponential profiles are best described by CTRE, however with YAMS they are supported by all motor controllers.

Motion Magic® ControlsPhoenix 6

How can I use Exponential Profiles?

All SmartMotorControllers support Exponential Profiles via the ExponentialProfilePIDController closed loop controller. You would just have to use ExponentialProfilePIDController instead of ProfiledPIDController or PIDController.

private final Distance chainPitch = Inches.of(0.25);
private final int toothCount = 22;
private final Distance circumference = chainPitch.times(toothCount);
private final Distance radius = circumference.div(2 * Math.PI);
private final Mass     weight = Pounds.of(16);
private final DCMotor  motors = DCMotor.getNEO(1);
private final MechanismGearing gearing = new MechanismGearing(GearBox.fromReductionStages(3, 4));

private final SmartMotorControllerConfig motorConfig        = new SmartMotorControllerConfig(this)
      .withMechanismCircumference(circumference)
      .withClosedLoopController(new ExponentialProfilePIDController(30, 0, 0, 
      ExponentialProfilePIDController.createElevatorConstraints(
                                     Volts.of(12), // Maximum voltage during profile
                                     motors, // Motors
                                     weight, // Carraige weight
                                     radius, // Drum radius
                                     gearing))) // Gearing
...

There are multiple ways to create constraints, like createArmConstraints or createFlyWheelConstraints or even createConstraints.

When should I use Exponential Profiles?

Exponential Profiles are easier to tune than Trapezoidal Profiles (from ProfiledPIDController) and are very good at overcoming mechanical failures to a point. It CANNOT speed up a mechanism that is massively under-powered and slow to move. Trapezoidal Profiles often fail miserably when a mechanism experiences disturbances along its movement, aside from fixing those disturbances an Exponential Profile is probably your best chance at getting it "working" quickly.