Elevator

Created a new class for the elevator subsystem

Uses position-based PID to move the elevator to the setpoint

Functions:

• Constructer: defines motor, encoder, and PID; sets encoderZeroed to false
• Up: changes setpoint by a positive incrementation from RobotMap
• Down: changes setpoint by a negative incrementation from RobotMap
• manualDown: changes speed to a negative value from RobotMap
• setSetpoint: changes the setpoint for the PID
• zeroEncoder: called at the beginning of autonomous once the elevator hits the lower switch, it resets the encoder and setpoint; after this is called PID is enabled
• reachedLowerLimit: checks to see if the elevator hit the bottom switch
• reachedUpperLimit: checks to see if the elevator hit the upper limit which is a value from RobotMap Periodic (Where PID setpoint and speeds are calculated and defined):
• First checks encoderZeroed value
• Once it is true, PID calculates the speed based on current position and setpoint
• Then checks to see if the elevator is at a limit and if it is moving in a direction that will pass the limit
• If it is the motor speed to 0
• If not it sets it to the calculated speed to get to the setpoint