Introduction to Commands

Why Commands?

Commands represent actions the robot can take. Commands enforce structure into how we tell the robot to make it more predictable. All commands share the same structure so once you learn that structure you will be able to write complex actions with the simple building blocks of Commands!

The 4 Parts of a Command

Basic commands have 4 components that are related to the action desired. 

Initialize

The Initialize method is called only once at the beginning of the command

Execute

the execute method is called every periodic cycle (every 20ms) code you put in here is run over and over again until the command is finished.

isFinished

the isFinished method is where we determine if the command should be finished it is also run every periodic cycle (every 20ms). Some commands we want to run until another command needs the subsystem and therefore we will return false. Others run until a condition is met and that logic is put within the isFinished method to return true when the command is supposed to end

End

This method is called at the End of the command once isFinished is True or another command needs the subsystem. Here we often set things back to the way they were before the command ran. 

Practice

First write out what you want the robot do so using template

First _________, then do ___________, Until ________, Finally do ________

For example if I want the robot to score a game piece from the claw it could be 

First Set claw motor to spit, then do ___________, Until  Claw no longer sees game piece, Finally do set claw motor to zero

 

 

Requirements

What if I asked you to type an essay and juggle? You cant because you would need your hands to only be doing one. The same is true for the robot we cannot ask the same hardware to do 2 things at once.