Using Odometry

The Odometry namespace contains four different classes that can be used for Odometry, depending on what sensors are on the robot. All four classes use pose exponentials, which allows for very accurate tracking, but using the classes that rely on more sensors will allow for the most accurate tracking.

Creating an odometry tracker

Two sensor odometry

The TwoSensorOdom class can only provide odometry tracking for differential drive robots. The constructor for TwoSensorOdom takes the following three arguments:

• AbstractOdomSensor &leftSensor

  The left side odometry sensor. This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• AbstractOdomSensor &leftSensor

  The right side odometry sensor. This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• LouLib::Units::Length trackWidth

  The distance between the left and right wheels that are used for tracking. This distance needs to be tuned to provide the most accurate tracking results.

Two sensor odometry with IMU

The TwoSensorIMUOdom class can only provide odometry tracking for differential drive robots. The extra IMU sensor will increase the accuracy of heading readings. The constructor for TwoSensorIMUOdom takes the following four arguments:

• AbstractOdomSensor &leftSensor

  The left side odometry sensor. This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• AbstractOdomSensor &leftSensor

  The right side odometry sensor. This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• LouLib::Units::Length trackWidth

  The distance between the left and right wheels that are used for tracking. This distance needs to be tuned to provide the most accurate tracking results.

• OdomIMUSensor &imuSensor - The IMU sensor used for heading.

Three sensor odometry

The ThreeSensorOdom class can provide odometry tracking for both differential drive and holonomic drive robots. For differential drive robots, the third sensor will account for any sideways drift. The constructor for ThreeSensorOdom takes the following five arguments:

• AbstractOdomSensor &leftSensor - The left side odometry sensor.

  This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• AbstractOdomSensor &leftSensor - The right side odometry sensor.

  This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• LouLib::Units::Length trackWidth - The distance between the

  left and right wheels that are used for tracking. This distance needs to be tuned to provide the most accurate tracking results.

• AbstractOdomSensor &backSensor - The odometry sensor placed

  perpendicular to the other two sensors. This is usually a OdomRotationSensor.

• LouLib::Units::Length backDist - The distance between the

  center of rotation of the robot and the back tracking wheel. This distance needs to be tuned to provide the most accurate tracking results.

Three sensor odometry with IMU

The ThreeSensorIMUOdom class can provide odometry tracking for both differential drive and holonomic drive robots. The extra IMU sensor will increase the accuracy of heading readings. For differential drive robots, the thrid sensor will account for any sideways drift. The constructor for ThreeSensorIMUOdom takes the following six arguments:

• AbstractOdomSensor &leftSensor

  The left side odometry sensor. This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• AbstractOdomSensor &leftSensor

  The right side odometry sensor. This can be either a OdomRotationSensor or a OdomMotorSensor depending on whether or not the robot has dead-wheels

• LouLib::Units::Length trackWidth

  The distance between the left and right wheels that are used for tracking. This distance needs to be tuned to provide the most accurate tracking results.

• AbstractOdomSensor &backSensor

  The odometry sensor placed perpendicular to the other two sensors. This is usually a OdomRotationSensor.

• LouLib::Units::Length backDist

  The distance between the center of rotation of the robot and the back tracking wheel. This distance needs to be tuned to provide the most accurate tracking results.

• OdomIMUSensor &imuSensor

  The IMU sensor used for heading.

Using the odometry tracker

All four of the odometry classes contain the same methods that can be used for odometry tracking:

• void setPose(LouLib::Math::Pose2D newPose)

  This method is used to set the current pose of the robot. Calling this method will erase any previous odometry tracking

• void update()

  This method is used to compute the updated pose of the robot.

• LouLib::Math::Pose2D getPose()

  This method is used to get the current pose of the robot.

Note

The update method should be called frequently into order to ensure accurate tracking.