Changes between Initial Version and Version 1 of ControlSystems/SoftwareTeam/Training/GettingStarted/Autonomous/CAN

Timestamp:

Nov 3, 2019, 9:00:17 PM (6 years ago)

Author:

David Albert

Comment:

--

ControlSystems/SoftwareTeam/Training/GettingStarted/Autonomous/CAN

@@ +1 @@
+Modify the generated code as follows:
+
+* Add the following imports:
+{{{
+import com.ctre.phoenix.motorcontrol.can.*;
+}}}
+
+*  Declare variables for the Motor controllers in the Robot class
+{{{ 
+   private WPI_TalonSRX leftMotor, rightMotor;
+}}}
+
+*  In robotInit() instantiate the motor controller objects
+  {{{
+    // CAN motor controllers connected to CAN bus (addrs 3,4)
+    leftMotor = new WPI_TalonSRX(3);
+    rightMotor = new WPI_TalonSRX(4);
+    // clear any previously configured settings
+    leftMotor.configFactoryDefault();
+    rightMotor.configFactoryDefault();
+    // Quadrature encoders are connected directly to the motor controllers
+    leftMotor.configSelectedFeedbackSensor(FeedbackDevice.QuadEncoder);
+    rightMotor.configSelectedFeedbackSensor(FeedbackDevice.QuadEncoder);
+  }}}
+
+* Add the following new method to the Robot class:
+  {{{
+     double raw2inches(int raw_count, int counts_per_rotation, double wheel_diameter) {
+        return (raw_count / counts_per_rotation) * (3.141492 * wheel_diameter);
+     }
+  }}}
+
+* Add the following to the robotPeriodic() method;  note the use of the [https://www.ctr-electronics.com/downloads/api/java/html/classcom_1_1ctre_1_1phoenix_1_1motorcontrol_1_1can_1_1_base_motor_controller.html#afb934a11682e710df123eec35aba1ba9 getSelectedFeedbackSensor()] method of the motor controller object which returns raw encoder counts:
+  {{{
+     // Encoders connected to CAN controller return raw counts
+     int l_raw = leftMotor.getSelectedSensorPosition();
+     int r_raw = rightMotor.getSelectedSensorPosition();
+     // display distances on smart dashboard
+     SmartDashboard.putNumber("Left", raw2inches(l_raw, 360*2, 7.5));
+     SmartDashboard.putNumber("Right", raw2inches(r_raw, 360*2, 7.5));
+  }}}
+
+* In autonomousInit() start the motors:
+  {{{
+    // start motors turning forward at 20% power
+    leftMotor.set(0.20);
+    // to go forward, left motor turns clockwise, right motor counter-clockwise
+    rightMotor.set(-0.20);
+  }}}
+
+* In the default section of autonomousPeriodic() stop if we've gone the desired distance.
+  Notice our first use of the logical OR operator (!||) to test whether either of two conditions is true
+  {{{
+        int l_raw = leftMotor.getSelectedSensorPosition();
+        int r_raw = rightMotor.getSelectedSensorPosition();
+        if ((raw2inches(l_raw, 360*2, 7.5) > 36.0) || 
+            (raw2inches(r_raw, 360*2, 7.5) > 36.0)) {
+           leftMotor.stopMotor();
+           rightMotor.stopMotor();
+        }
+  }}}