Overview

The tedusar_daf_path_follower is a simple but efficient path follower for skid-steered/differential drive mobile robots as part of tedusar_ros_pkg repository. To control path follower a tedusar_nav_msgs package is needed which define control messages.

Dynamic Arc Fitting Path Follower

The DAF Path Follower provide control commands (linear and rotational velocity) based on given path designated to follow. Behaviour of the DAF path follower can be adapted to your needs with given Parameters.

ROS Parameters

- base_link (string):

• Mobile robot base link , default /base_footprint.

- pub_cmd_hz (double):

• Frequency of veloctiy commands publishing, default 10 Hz.

- path_topic (nav_msgs/Path):

• ROS subscription topic name to path waypoints, default /exploration_path

- pose_update_topic (nav_msgs/Odometry):

• Subscription topic name to robot current position, default /odom.

- imu_data (sensor_msgs/Imu):

• IMU information subscription topic name, default /imu_data.

- out_cmd_vel (geometry_msgs/Twist):

• Velocity publisher topic name, default /cmd_vel.

- max_lin_vel (double):

• Maximum linear velocity (m/s), default 0.4.

- min_lin_vel (double):

• Minimum linear velocity (m/s), default 0.1.

- max_rot_vel (double):

• Maximum rotational velocity (rad/s), default 0.8.

- min_rot_vel (double):

• Minimum rotational velocity (rad/s), default 0.4.

- executin_period (double):

• Execution period defines distance parameter lookahead (m) which is second, distance is calculated execution_period*max_lin_vel, default 1.0.

- global_goal_tolerance (double):

• DAF path follower report goal reached if tolerance is reached (m), default 0.1.

- enable_angle_compensation (bool):

• Allows DAF to compensate angle difference while moving, based on following params, default true. - lower_al_angle (double):

  • This parameter defines lower angle treshold which defines if compensation (rad), default /0.2.

  - upper_al_angle (double):

  • This parameter defines lower angle treshold which defines if compensation (rad), default /1.0.

- enable_ground_compensation (bool):

• Allows DAF to use IMU data and compensate angle of inclination while execution velocity commands, default true.

- enable_velocity_compensation (bool):

• Allows DAF to increase linear and rotational veloctiy if robot does not reach on given velocity commands, default true.

- stability_angle (double):

• This is an angle thresholf, when it is reached the DAF path follower reponde with failure and warn that robot is inclined too much, default 1.0.

- show_local_path_planning (bool):

• It publish additional topics wich are display auxilary geometry information, additional information are need, default false.

• - map_link (string):

  • Map link, for dispaying additonal information , default /map.

Launch File Examples

Start a tedusar_path_follower process with default parameter setings.

 $ roslaunch tedusar_daf_path_follower daf_path_follower_default.launch

Other Documentation

Publication: