ArmFeedforward 
A helper class that computes feedforward outputs for a simple arm (modeled as a motor
acting against the force of gravity on a beam suspended at an angle).

ControllerUtil 

ElevatorFeedforward 
A helper class that computes feedforward outputs for a simple elevator (modeled as a motor
acting against the force of gravity).

PIDController 
Implements a PID control loop.

ProfiledPIDController 
Implements a PID control loop whose setpoint is constrained by a trapezoid
profile.

RamseteController 
Ramsete is a nonlinear timevarying feedback controller for unicycle models
that drives the model to a desired pose along a twodimensional trajectory.

SimpleMotorFeedforward 
A helper class that computes feedforward outputs for a simple permanentmagnet DC motor.
