vrx_2022 gymkhana_task

Task 5: Channel Navigation, Acoustic Beacon Localization and Obstacle Avoidance

Summary

This task requires the system to combine several fundamental capabilities. In the first part of the task, the vehicle must traverse a channel marked by pairs of colored buoys. After passing through the final gate in the channel, the vehicle enters the second part of the task, in which it must searchs for an underwater acoustic pinger marking the location of a black box. The vehicle should navigate to the pinger and hold station as close as possible to the pinger.

How to Practice

Step 1: Launch the example

roslaunch vrx_gazebo gymkhana.launch

Step 2: Subscribe to relevant topics

The following ROS topics contain information relevant to this task:

/vrx/gymkhana_blackbox/goal
/vrx/gymkhana_blackbox/pose_error
/vrx/gymkhana_blackbox/mean_pose_error
/vrx/task/info
/wamv/sensors/pingers/pinger/range_bearing

For the timeout counter and your current score, subscribe to the /vrx/task/info topic:

rostopic echo /vrx/task/info

To complete the second part of the task, you will also need to subscribe to the acoustic pinger topic:

rostopic echo /wamv/sensors/pingers/pinger/range_bearing

Step 3: Complete the task

• Navigate the channel.
• Use the range_bearing information from the acoustic pinger to locate the black box.
• Drive the vehicle as close as possible to the black box and remain at this location until the task times out.

Notes / Hints:

• Even though the gymkhana_channel and gymkhana_blackbox portions each has its own task/info topics, the final timeout and score go by the top-level topic.
• The topics associated with the navigation channel are not relevant to the task and can be disregarded. However, Gazebo messages such as [Msg] New gate crossed! and [Msg] Course completed! will be printed to the terminal, if you launch the task with argument extra_gazebo_args:=--verbose

Important: Make sure to use only the acoustic pinger to determine the goal pose.

• Note that, for debugging purposes:
  • /vrx/gymkhana_blackbox/goal provides the absolute goal pose.
  • /vrx/gymkhana_blackbox/pose_error provides the ground truth pose error
  • /vrx/gymkhana_blackbox/mean_pose_error provides the mean pose error.
• These topics are for debugging purposes only and will not be available to the system in the actual competition.