Changes between Version 8 and Version 9 of ControlSystems/SoftwareTeam/Training/GettingStarted/IntroRobotJava

Timestamp:

Oct 12, 2019, 11:32:19 PM (6 years ago)

Author:

David Albert

Comment:

--

ControlSystems/SoftwareTeam/Training/GettingStarted/IntroRobotJava

@@ -24 +24 @@
 * testPeriodic() - called periodically while robot is in test mode
 
-You will put your setup code in the Init() functions and the code that should run repeatedly in the Periodic() functions.
+You will put your setup code in the Init() functions and the code that should run repeatedly in the Periodic() functions.  The code will make use of the pre-existing [https://first.wpi.edu/FRC/roborio/beta/docs/java/edu/wpi/first/wpilibj/XboxController.html XboxController] class provided in WPILib that makes it easy to use an Xbox controller.
 
 Modify the newly created program as follows:
@@ -36 +36 @@
 * In the function robotPeriodic() addd: {{{ SmartDashboard.putNumber("Left Joystick X", xbox.getX(Hand.kLeft)); }}}
 
-Your program should look like [wiki://ControlSystems/IntroRobotJava/XboxExample this]
+Your program should look like [wiki://ControlSystems/SoftwareTeam/Training/IntroRobotJava/XboxExample this]
 
 * Use the WPILib icon to build your new program: W->Build Robot Code
@@ -70 +70 @@
   }}}
 
-Run the program and observe the "Front range" value in the Smart Dashboard as you move the robot towards and away from the wall.
+Run the program and observe the "Front range" value in the [https://wpilib.screenstepslive.com/s/currentCS/m/java/l/599724-displaying-data-on-the-ds-dashboard-overview Smart Dashboard] as you move the robot towards and away from the wall.
+
+== Third program: Servo Motor Control
+
+Create another program using the !TimedRobot java template and name it !ServoTest. Modify the generated code as follows:
+* Add the following imports:
+{{{
+import edu.wpi.first.wpilibj.XboxController;
+import edu.wpi.first.wpilibj.GenericHID.Hand;
+import edu.wpi.first.wpilibj.Servo;
+}}}
+* declare variable for the Xbox controller and [https://wpilib.screenstepslive.com/s/currentCS/m/java/l/599703-repeatable-low-power-movement-controlling-servos-with-wpilib servo motor] in the Robot class 
+{{{ 
+   private XboxController xbox; 
+   private Servo servo;
+}}}
+* in robotInit() instantiate the controller and motor objects
+  {{{
+    xbox = new XboxController(0); // Xbox controller on port 0
+    servo = new Servo(1);         // Servo connected to PWM 1
+  }}}
+* in teleopPeriodic() read the xbox controller and adjust the servo motor accordingly
+  {{{
+    // Read xbox controller left joystick x axis
+    // value returned is between -1.0 and 1.0
+    double x = xbox.getX(Hand.kLeft); 
+    // Servo motors are controlled on a scale of 0.0 to 1.0
+    // so re-scale the X value to that range (-1.0->0, 0->0.5, 1.0->1.0)
+    x = (x + 1.0) / 2;
+    // Set servo motor position based on joystick
+    servo.set(x); 
+  }}}
+
+Connect a Servo motor to PWM port 1 on the roboRIO and run your program.  You'll need to press the Enable button on the driver station to put the robot in Teleop mode so that teleopPeriodic() is called repeatedly.
  
 == Study some examples