noetic

Overview

This package contains a ROS node which enables the Leo Rover to follow a printed ARTag.

It is one of a couple of packages made for showing an example usage of a stock Leo Rover.

Usage

To run the follower simply type:

roslaunch leo_example_follow_ar_tag follow_ar_tag.launch

It will use the base configuration from the yaml files. You can run the node with your configuration by changing the parameters (described in ROS API section)

ROS API

follow_ar_tag

Subscribed Topics

ar_pose_marker (ar_track_alvar_msgs/AlvarMarkers)

• The detected markers

wheel_odom_with_covariance (nav_msgs/Odometry)

• The wheel odometry used for interpolating the position between marker detections.

Published Topics

cmd_vel (geometry_msgs/Twist)

• The velocity commands that should follow the marker.

Parameters

follow_id (int, default: 0)

• The ID of the marker to follow.

marker_timeout (float, default: 0.5)

• The timeout after which the rover will stop moving when it loses track of the marker.

min_ang_vel (float, default: 0.1)

• The minimum angular velocity of the rover.

max_ang_vel (float, default: 1.0)

• The maximum angular velocity of the rover.

angle_min (float, default: 0.1)

• The minimum angle between the rover and the marker, for which the rover will start rotating (with the min_ang_vel velocity).

angle_max (float, default: 0.7)

• The marker angle for which the maximum angular velocity is applied. For angles between angle_min and angle_max the applied velocity linearly increases from min_ang_vel to max_ang_vel.

min_lin_vel_forward (float, default: 0.1)

• The minimum linear velocity of the rover when driving forward.

max_lin_vel_forward (float, default: 0.4)

• The maximum linear velocity of the rover when driving forward.

distance_min_forward (float, default: 0.7)

• The minimum distance to the marker from the rover, for which the rover will start moving forward (with the min_lin_vel_forward).

distance_max_forward (float, default: 1.2)

• The distance to the marker for which the maximum linear velocity is applied. For distances between distance_min_forward and distance_max_forward the applied velocity linearly increases from min_lin_vel_forward to max_lin_vel_forward.

min_lin_vel_reverse (float, default: 0.1)

• The minimum linear velocity of the rover when going backward.

max_lin_vel_reverse (float, default: 0.2)

• The maximum linear velocity of the rover when going backward.

distance_max_reverse (float, default: 0.5)

• The distance to the marker below which the rover will start moving backward (with the min_lin_vel_reverse velocity).

distance_min_reverse (float, default: 0.4)

• The distance to the marker for which the maximum linear velocity is applied. For distances between distance_max_reverse and distance_min_reverse the applied velocity linearly increases from min_lin_vel_reverse to max_lin_vel_reverse.