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Note: This tutorial assumes that you have completed the previous tutorials: Basic ROV Usage.
(!) Please ask about problems and questions regarding this tutorial on answers.ros.org. Don't forget to include in your question the link to this page, the versions of your OS & ROS, and also add appropriate tags.

Intermediate ROV Usage

Description: More instructions for using your ROV.

Tutorial Level: INTERMEDIATE

ROS Introspection Tools

ROS includes a variety of tools to interrogate a running system. This is a brief overview on a few of them.

rostopic

The rostopic command will list and display ROS network messages from the command line. With the BlueROV core services running, try the follow commands:

rostopic list
rostopic hz mavros/rc/override
rostopic echo mavros/rc/override

rqt

rqt is a plugin-based framework for GUI widgets. Some of our favorite plugins include:

rviz

rviz fuses many types of information into a 3D world for real-time viewing. An rviz configuration ships with the bluerov package. Try it out like this:

roslaunch bluerov rviz.launch

The pilot and teleop_xbox nodes can be configured while running using the command:

`bash rosrun rqt_reconfigure rqt_reconfigure `

![rqt_reconfigure](bluerov-rqt-reconfigure.jpg)

Note that configuration changes during runtime do not persist. Make sure to update the appropriate file in the config/ directory to persist changes.

Saving and Replaying Data

One of the power features of ROS is the ability to record and play back data. Check out the rosbag docs for more info on this.

Exporting Video from ROS Bags

Old process:

# terminal window 1
roscore
rosbag play -d 2 something.bag

# terminal window 2
mkdir export
cd export
rosrun image_view extract_images image:=/camera/image _image_transport:=compressed

# in terminal window 2 after export has finished
cd ..
mencoder "mf://export/*.jpg" -mf type=jpg:fps=30 -o output.mpg -speed 1 -ofps 30 -ovc lavc -lavcopts vcodec=mpeg2video:vbitrate=2500 -oac copy -of mpeg
 1341  mkdir bag1

Automatically Start ROS On Bootup

To automatically launch ROS on startup, install robot_upstart and then run:

rosrun robot_upstart install bluerov/launch/bluerov_r1.launch

Manually control the upstart job with these:

sudo service bluerov start
sudo service bluerov stop

Check the log like this:

sudo tail /var/log/upstart/bluerov.log -n 30

Preparing for a Mission

If you don't have a body of water within a couple of feet of your workstation, performing a wet test can turn into a big ordeal. Here is a checklist of items that we use to ensure everything is good to go before leaving for a wet test or actual mission.

Before you head out for a wet test, make sure that you do as much preparation as possible ahead of time. In particular, attempt to exercise the complete functionality of the ROV as much as possible before heading out for the test.

Mission Checklist

Here is a sample list of what to bring on a mission.

Item

Notes

ROV

dry-run motors, teleop control, and camera ahead of time

ROV batteries

check charge

external camera(s)

check charge

teleop controller

check charge and don't forget wireless dongle if applicable

workstation/laptop

check charge

weights

to fine-tune buoyancy

silicone grease

to keep o-rings and penetrators lubricated

other tools

cause you never know

a towel

to dry things off

replacement parts

to replace something if it breaks


2019-04-20 12:29