Package edu.wpi.first.wpilibj

Class AnalogGyro

java.lang.Object
edu.wpi.first.wpilibj.AnalogGyro
All Implemented Interfaces:
Sendable, AutoCloseable
public class AnalogGyro
extends Object
implements Sendable, AutoCloseable
Use a rate gyro to return the robots heading relative to a starting position. The Gyro class tracks the robots heading based on the starting position. As the robot rotates the new heading is computed by integrating the rate of rotation returned by the sensor. When the class is instantiated, it does a short calibration routine where it samples the gyro while at rest to determine the default offset. This is subtracted from each sample to determine the heading.

This class is for gyro sensors that connect to an analog input.

  • Constructor Summary

    Constructors 
    Constructor Description
    AnalogGyro​(int channel)
    Gyro constructor using the channel number.
    AnalogGyro​(int channel, int center, double offset)
    Gyro constructor using the channel number along with parameters for presetting the center and offset values.
    AnalogGyro​(AnalogInput channel)
    Gyro constructor with a precreated analog channel object.
    AnalogGyro​(AnalogInput channel, int center, double offset)
    Gyro constructor with a precreated analog channel object along with parameters for presetting the center and offset values.

  • Method Summary

    Modifier and Type Method Description
    void calibrate()
    Calibrate the gyro by running for a number of samples and computing the center value.
    void close()
    Delete (free) the accumulator and the analog components used for the gyro.
    AnalogInput getAnalogInput()
    Gets the analog input for the gyro.
    double getAngle()
    Return the heading of the robot in degrees.
    int getCenter()
    Return the gyro center value set during calibration to use as a future preset.
    double getOffset()
    Return the gyro offset value set during calibration to use as a future preset.
    double getRate()
    Return the rate of rotation of the gyro.
    Rotation2d getRotation2d()
    Return the heading of the robot as a Rotation2d.
    void initSendable​(SendableBuilder builder)
    Initializes this Sendable object.
    void reset()
    Reset the gyro.
    void setDeadband​(double volts)
    Set the size of the neutral zone.
    void setSensitivity​(double voltsPerDegreePerSecond)
    Set the gyro sensitivity.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • AnalogGyro

      public AnalogGyro​(int channel)
      Gyro constructor using the channel number.
      Parameters:
      channel - The analog channel the gyro is connected to. Gyros can only be used on on-board channels 0-1.

    • AnalogGyro

      public AnalogGyro​(AnalogInput channel)
      Gyro constructor with a precreated analog channel object. Use this constructor when the analog channel needs to be shared.
      Parameters:
      channel - The AnalogInput object that the gyro is connected to. Gyros can only be used on on-board channels 0-1.

    • AnalogGyro

      public AnalogGyro​(int channel, int center, double offset)
      Gyro constructor using the channel number along with parameters for presetting the center and offset values. Bypasses calibration.
      Parameters:
      channel - The analog channel the gyro is connected to. Gyros can only be used on on-board channels 0-1.
      center - Preset uncalibrated value to use as the accumulator center value.
      offset - Preset uncalibrated value to use as the gyro offset.

    • AnalogGyro

      public AnalogGyro​(AnalogInput channel, int center, double offset)
      Gyro constructor with a precreated analog channel object along with parameters for presetting the center and offset values. Bypasses calibration.
      Parameters:
      channel - The analog channel the gyro is connected to. Gyros can only be used on on-board channels 0-1.
      center - Preset uncalibrated value to use as the accumulator center value.
      offset - Preset uncalibrated value to use as the gyro offset.

  • Method Details

    • calibrate

      public void calibrate()
      Calibrate the gyro by running for a number of samples and computing the center value. Then use the center value as the Accumulator center value for subsequent measurements.

      It's important to make sure that the robot is not moving while the centering calculations are in progress, this is typically done when the robot is first turned on while it's sitting at rest before the competition starts.

    • getRotation2d

      public Rotation2d getRotation2d()
      Return the heading of the robot as a Rotation2d.

      The angle is continuous, that is it will continue from 360 to 361 degrees. This allows algorithms that wouldn't want to see a discontinuity in the gyro output as it sweeps past from 360 to 0 on the second time around.

      The angle is expected to increase as the gyro turns counterclockwise when looked at from the top. It needs to follow the NWU axis convention.

      This heading is based on integration of the returned rate from the gyro.

      Returns:
      the current heading of the robot as a Rotation2d.

    • reset

      public void reset()
      Reset the gyro.

      Resets the gyro to a heading of zero. This can be used if there is significant drift in the gyro, and it needs to be recalibrated after it has been running.

    • close

      public void close()
      Delete (free) the accumulator and the analog components used for the gyro.
      Specified by:
      close in interface AutoCloseable

    • getAngle

      public double getAngle()
      Return the heading of the robot in degrees.

      The angle is continuous, that is it will continue from 360 to 361 degrees. This allows algorithms that wouldn't want to see a discontinuity in the gyro output as it sweeps past from 360 to 0 on the second time around.

      The angle is expected to increase as the gyro turns clockwise when looked at from the top. It needs to follow the NED axis convention.

      This heading is based on integration of the returned rate from the gyro.

      Returns:
      the current heading of the robot in degrees.

    • getRate

      public double getRate()
      Return the rate of rotation of the gyro.

      The rate is based on the most recent reading of the gyro analog value

      The rate is expected to be positive as the gyro turns clockwise when looked at from the top. It needs to follow the NED axis convention.

      Returns:
      the current rate in degrees per second

    • getOffset

      public double getOffset()
      Return the gyro offset value set during calibration to use as a future preset.
      Returns:
      the current offset value

    • getCenter

      public int getCenter()
      Return the gyro center value set during calibration to use as a future preset.
      Returns:
      the current center value

    • setSensitivity

      public void setSensitivity​(double voltsPerDegreePerSecond)
      Set the gyro sensitivity. This takes the number of volts/degree/second sensitivity of the gyro and uses it in subsequent calculations to allow the code to work with multiple gyros. This value is typically found in the gyro datasheet.
      Parameters:
      voltsPerDegreePerSecond - The sensitivity in Volts/degree/second.

    • setDeadband

      public void setDeadband​(double volts)
      Set the size of the neutral zone. Any voltage from the gyro less than this amount from the center is considered stationary. Setting a deadband will decrease the amount of drift when the gyro isn't rotating, but will make it less accurate.
      Parameters:
      volts - The size of the deadband in volts

    • getAnalogInput

      public AnalogInput getAnalogInput()
      Gets the analog input for the gyro.
      Returns:
      AnalogInput

    • initSendable

      public void initSendable​(SendableBuilder builder)
      Description copied from interface: Sendable
      Initializes this Sendable object.
      Specified by:
      initSendable in interface Sendable
      Parameters:
      builder - sendable builder