Diff Drive

This plugin provides common features for a differential drive robots. All velocities and odometries are w.r.t. the robot origin

• Subscribes to a topic publishing geometry_msgs/Twist messages, and move the robot at the desired forward and rotation velocities
• Publishes to two topics with nav_msgs/Odometry messages, one for robot odometry which has noise, the other the ground truth odometry

plugins:

    # required, specify DiffDrive type to load the plugin
  - type: DiffDrive

    # required, name of the plugin
    name: turtlebot_drive

    # required, body of a model to set velocities and obtain odometry
    body: base

    # optional, defaults to odom, the name of the odom frame
    odom_frame_id: odom

    # optional, defaults to inf, rate to publish odometry at, in Hz
    pub_rate: .inf

    # optional, defaults to "cmd_vel", the topic to subscribe for velocity
    # commands
    twist_sub: cmd_vel

    # optional, defaults to "odometry/filtered", the topic to advertise for
    # publish noisy odometry
    odom_pub: odometry/filtered

    # optional, defaults to "odometry/ground_truth", the topic to advertise for publish
    # no noise ground truth odometry
    ground_truth_pub: odometry/ground_truth

    # optional, defaults to "twist", the topic to publish noisy local frame velocity
    # that simulates encoder readings
    twist_pub: twist

    # optional, defaults to true, enables the advertising and publishing of both
    # ground truth and noisy odometry
    enable_odom_pub: true

    # optional, defaults to true, enables the publishing of the TF between
    # 'base_link' (or link specified in "body") and 'odom' links.
    # Disable if your code has its own TF publisher for these two links.
    enable_odom_tf_pub: true

    # optional, defaults to true, enables the advertising and publishing of noisy local
    # frame velocity
    enable_twist_pub: true

    # optional, defaults to [0, 0, 0], corresponds to noise on [x, y, yaw],
    # the variances of gaussian noise to apply to the pose components of the
    # odometry message
    odom_pose_noise: [0, 0, 0]

    # optional, defaults to [0, 0, 0], corresponds to noise on
    # [x velocity, y velocity, yaw rate], the variances of gaussian noise to
    # apply to the twist components of the odometry message
    odom_twist_noise: [0, 0, 0]

    # optional, defaults to the diagonal [x, y, yaw] components replaced by
    # odom_pose_noise with all other values equals zero, must have length of 36,
    # represents a 6x6 covariance matrix for x, y, z, roll, pitch, yaw.
    # This does not involve in any of the noise calculation, it is simply
    # the output values of odometry pose covariance
    odom_pose_covariance: [0, 0, 0, 0, 0, 0,
                           0, 0, 0, 0, 0, 0,
                           0, 0, 0, 0, 0, 0,
                           0, 0, 0, 0, 0, 0,
                           0, 0, 0, 0, 0, 0,
                           0, 0, 0, 0, 0, 0]

    # optional, defaults to the diagonal [x velocity, y velocity, yaw rate]
    # components replaced by odom_twist_noise with all other values equals zero,
    # must have length of 36, represents a 6x6 covariance matrix for rates x,
    # y, z, roll, pitch, yaw. This does not involve in any of the noise
    # calculation, it is simply the output values of odometry twist covariance
    odom_twist_covariance: [0, 0, 0, 0, 0, 0
                           0, 0, 0, 0, 0, 0
                           0, 0, 0, 0, 0, 0
                           0, 0, 0, 0, 0, 0
                           0, 0, 0, 0, 0, 0
                           0, 0, 0, 0, 0, 0]

    # optional, defaults each parameter to 0.0 which means "no limit"
    # sets dynamics constraints on angular velocity, acceleration (in rads/sec; rads/sec/sec)
    angular_dynamics:
      acceleration_limit: 0.0   # max acceleration (away from 0), in rads/s/s; 0.0 means "no limit"
      deceleration_limit: 0.0   # max deceleration (towards 0), in rads/s/s; 0.0 means "no limit"; left blank, will default to acceleration_limit value
      velocity_limit: 0.0       # max absolute velocity in rads/s; 0.0 means "no limit"

    # optional, defaults each parameter to 0.0 which means "no limit"
    # sets dynamics constraints on linear velocity, acceleration (in m/s; m/s/s)
    linear_dynamics:
      acceleration_limit: 0.0   # max acceleration (away from 0), in m/s/s; 0.0 means "no limit"
      deceleration_limit: 0.0   # max deceleration (towards 0), in m/s/s; 0.0 means "no limit"; left blank, will default to acceleration_limit value
      velocity_limit: 0.0       # max absolute velocity in m/s; 0.0 means "no limit"

    ground_truth_frame_id: map  # The name of the ground truth origin TF frame