Elevator Subsystem Example

Use this as a reference when programming an elevator in the future!

What it does:

This is just a full, can be simulated, elevator subsystem in WPILib. It contains all the information you should know and what you should do to program an elevator. It uses 2 Kraken x60s and CTRE MotionMagic©

High Level Overview:

In ElevatorSubsystem.java

Initialize all your objects:

• Elevator leader motor
• Elevator follower motor(will do exactly what the leader motor does in reverse)
• Motor Control
• Mechanism2d
• Mechanism root
• Mechanism Ligament(represents whole elevator)
• ElevatorSim physics simulation
• Elevator setpoint in meters

Constructor:

Configure motor:

• state the brake mode
• state the inversion mode
• configure PID and gravity type
• configure motion magic control parameters
• set current limits (supply and stator)
• make the follower motor follow the leader motor
• apply same config to both motors

Periodic (Happens once every 20msec):

• Put data on SmartDashBoard, especially the elevator's Mechanism2d

SimulationPeriodic(Same as periodic but only happens in simulation mode)

• set supply voltage to 12
• set the input to the elevator physics simulation
• update it with a delay of 0.2 secs (20msec)
• set the rotor position and velocity for simulated motors using data from the physics simulation
• set the ligament length to the physics simulation length

Some helper methods

• getElevatorPositionMeters()
• hasReachedAngle()

Setting elevator position

• clamp the input to the min/max range
• convert meters given to rotations
• set the control parameters, such as the position to go to and the slot to use
• set the motor's control to the control object

Challenge

go eat a candy bar