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

Timestamp:

Nov 3, 2019, 8:57:14 PM (6 years ago)

Author:

David Albert

Comment:

--

ControlSystems/SoftwareTeam/Training/GettingStarted/Autonomous/PWM

@@ +1 @@
+Modify the generated code as follows:
+
+* Add the following imports:
+{{{
+import edu.wpi.first.wpilibj.Encoder;
+import com.ctre.phoenix.motorcontrol.can.*; // for Hazelnut
+import edu.wpi.first.wpilibj.Talon;         // for Macadamia
+}}}
+
+*  Declare variables for the Encoders and Motor controllers in the Robot class
+{{{ 
+
+  // Uncomment next 2 lines for PWM motor controllers (Macademia)
+  // private Talon leftMotor, rightMotor;
+  // private Encoder leftEncoder, rightEncoder;
+
+  // Uncomment next line for CAN motor controllers (Hazelnut)
+  // private WPI_TalonSRX leftMotor, rightMotor;
+}}}
+
+*  In robotInit() instantiate the Encoder and Motor objects
+  * For PWM Motor Controller robots (Macadamia):
+  {{{    
+    // Quadrature encoder has A and B channels connected to DIO0,1, DIO2,3
+    leftEncoder = new Encoder(0, 1);
+    rightEncoder = new Encoder(2, 3);
+    // Peanut wheels are 7.5" in diameter
+    // Encoders provide 1 count per degree of rotation
+    leftEncoder.setDistancePerPulse((3.141592*7.5)/360);
+    rightEncoder.setDistancePerPulse((3.141592*7.5)/360);
+    // PWM motor controllers connected to PWM0, PWM1
+    leftMotor = new Talon(0);
+    rightMotor = new Talon(1);
+  }}}
+  * For CAN Motor Controller robots (Hazelnut): 
+  {{{
+    // 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();
+    // Encoders are connected directly to the motor controllers
+    leftMotor.configSelectedFeedbackSensor(FeedbackDevice.QuadEncoder);
+    rightMotor.configSelectedFeedbackSensor(FeedbackDevice.QuadEncoder);
+  }}}
+
+* For PWM controller robots (Macadamia),[[BR]] 
+  in robotPeriodic() display the encoder values:
+  {{{
+    SmartDashboard.putNumber("Left", leftEncoder.getDistance());
+    SmartDashboard.putNumber("Right", rightEncoder.getDistance());
+  }}}
+* For CAN motor controllers (Hazelnut):  
+     * First 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() reset the encoder counts and start the motors:
+  {{{
+    // For PWM controllers (Macadamia) uncomment the next 2 lines to reset encoder counts to 0
+    // leftEncoder.reset();
+    // rightEncoder.reset();
+    // 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
+  * For PWM motor controllers:
+  {{{
+        if ((leftEncoder.getDistance() > 36.0) || 
+            (rightEncoder.getDistance() > 36.0)) {
+           leftMotor.stopMotor();
+           rightMotor.stopMotor();
+        }
+  }}}
+  * For CAN motor controllers:
+  {{{
+        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();
+        }
+  }}}