Command Based Programming

Subsystems are what defines the capabilities of each mechanism on the robot. You can think of it as different physical parts of the robot.  Some examples are a climber, an intake, a ball shooter, and a drive train.

Commands are the operation of the robot, utilizing the capabilities that are in the subsystems. You can think of this as giving actions or commands to the different parts of the robot. For example, If your robot code has a subsystem for an intake, the program would have a command for taking in the balls called “intake” and this will spin a motor to take in the balls.

Subsystems have methods where you can declare the hardware, like a motor,  that will be used by the commands. These methods are then used to control different mechanisms on the robot. 

If the robot has an intake arm, the intake arm will have to do 2 things. It has to move up and move down. In order to make this happen, you have to add two methods. The first method will be called public void armUp()methods. Inside this method you will set your motor to move up. The second method will be called. Inside this method you will set up your motor to move down. You can see how this looks by looking at the team’s code. 

Commands use many methods to define a robot's action. When a programmer creates a command or looks at the example command given, they will see that there are about 4 methods. They are:

• initialized(): This is called before the command runs for the first time.

• execute(): This method is the code that has the operations to complete a task. It is basically where the logic goes.

• isFinished(): This tells if the action is done or not. After the code in execute() runs, it goes to the isFinished() method to see if the action is completed. It returns true when finished and false when not. If the action is completed and isFinished() returns true, it moves to end(). If the action is not completed, it continues until it is done.

• end(): This has the code for what the robot should do after isFinished() returns true. This method is also called when the command is interrupted.

The OI (Operator Interface) is a class where you declare and get information from other operator interface devices such as joystick, xbox controllers, and wii remotes.