[ros-users] wavefront

Wed Mar 31 23:07:04 UTC 2010

Dan,

First off, glad to hear that at least the basic stuff is working.

On Wed, Mar 31, 2010 at 10:48 AM, Dan Lazewatsky
<lazewatskyd at cse.wustl.edu>wrote:

>  Eitan,
> I copied nav_view.xml from move_base_stage/move_base, changing the
> remappings to topics that exist in my system. That along with your two
> suggestions seem to have done the trick. There are, however, a few odd
> things:
>

> -when I start up nav_view, the map takes a *really* long time to show up -
> on the order of 5 minutes
>

We've seen things like this when our network communication is really bad.
Are you talking to the robot over a wireless link? Have you looked at the
ping times to the robot? If you have a solid connection, it'd be strange to
see the map take that long.

> -once the robot gets to its goal, it spins around a lot before stopping
>

It may be that the robot is having a bit of trouble achieving its goal
within the user-specified tolerances. This could be due to AMCL being a
little bit off or overshoot by the robot when it rotates in place (see
ticket: https://code.ros.org/trac/ros-pkg/ticket/3127). You might want to
try setting the goal tolerance parameters (
http://www.ros.org/wiki/base_local_planner#Goal_Tolerance_Parameters) on the
base_local_planner to be a little more lenient... particularly the
rotational one.

> -nav_view seems a bit unstable - ubuntu frequently grays it out thinking
> it's crashed
>

This again seems like nav_view is losing connectivity to the robot. My first
hunch is that the network connection is a bit flaky.

Hope all is well,

Eitan

>
> Thanks for the help,
> -Dan
>
>
> On 3/31/10 12:24 PM, Eitan Marder-Eppstein wrote:
>
> Dan,
>
> The Costmap2DROS transform timeouts could be a problem if they don't taper
> off after startup. A bunch of warnings right as you start isn't unexpected,
> but if they just keep spewing that means there is likely a timing issue. Do
> they keep spewing constantly or more or less stop after a few seconds?
>
> After looking at your configuration files, it seems that you're missing a
> pretty important line in costmap_common_params.yaml. You define a
> "laser_scan_sensor," but you never actually tell the navigation stack to use
> it. As such, you'll never see obstacles show up in the costmap. Add the
> following line to your costmap_common_params.yaml file:
>
> observation_sources: laser_scan_sensor
>
> This will tell the navigation stack that you'd like to use the
> laser_scan_sensor you defined.
>
> Hopefully, adding that line should get obstacles to show up for you.
> However, even without that, I would've expected the robot to move when you
> set a goal, it would just hit stuff. Are you sure that you were sending a
> goal on the correct topic? In rviz, you need to make sure to set the 2D Nav
> Goal topic to "move_base_simple/goal." I believe that both rviz and nav_view
> by default send to the "goal" topic instead. If you want to use nav_view,
> you'll have to remap in your launch file. You can see
> move_base_stage/move_base/nav_view.xml for an example of this.
>
> Oh... I think I may know why the robot doesn't move, you've defined your
> footprint by only 2 points. The navigation stack supports any convex polygon
> for a footprint and, therefore, needs at least three points to run. It also
> assumes that the robot is centered at (0, 0). If you want to define a square
> robot of the dimensions in your launch file you'll need to use the
> following:
>
> footprint: [[-0.2, -0.2], [-0.2, 0.2], [0.2, 0.2], [0.2, -0.2]]
>
> You should have received a warning about this, but I just realized that the
> costmap uses ROS_ASSERT where it should be using ROS_FATAL. This means that
> all those warnings will be compiled out when run in release mode. I've
> ticketed fixing this here: https://code.ros.org/trac/ros-pkg/ticket/3939
>
> Hope this helps and let me know how things go... we'll figure it out yet,
>
> Eitan
>
> On Wed, Mar 31, 2010 at 8:13 AM, Dan Lazewatsky <lazewatskyd at cse.wustl.edu
> > wrote:
>
>>
>> On 3/30/10 7:55 PM, Eitan Marder-Eppstein wrote:
>>
>> Hey Dan,
>>
>> A few questions for ya to help figure out what's going on:
>>
>> 1) Have you tried using the rxconsole tool to see if any useful
>> information is being output from the system? If so, did you see anything
>> that seemed to be complaining or giving warnings?
>>
>>  rxconsole doesn't show anything that seems too concerning. The worst is a
>> bunch of
>> Costmap2DROS transform timeout. Current time: ...
>>
>>
>> 2) What launch files are you running on the erratic? Are they the ones in
>> the 2dnav_erratic package? Or different ones that you created? We used to
>> have an erratic in-house, but we don't anymore and its been awhile since the
>> 2dnav_erratic package has been tested. If you're running with your own
>> configuration, could you post the files so I can take a look at them?
>>
>>  I've attached the launch file and config files I'm using. The config
>> files were all setup according to this:
>> http://www.ros.org/wiki/navigation/Tutorials/RobotSetup
>>
>>
>> 3) Do you see any obstacles in nav_view? On second thought, rviz is a more
>> powerful debugging tool for this kind of stuff. Have you tried using rviz to
>> get useful debugging information (whether obstacles show up, a plan is
>> created, etc)? You can find a tutorial on using rviz with the navigation
>> stack here:
>> http://www.ros.org/wiki/navigation/Tutorials/Using%20rviz%20with%20the%20Navigation%20Stack
>>
>>  nav_view and rviz don't show any obstacles, plan, or really anything but
>> the map. If I'm really lucky, rviz will show the amcl particle cloud.
>>
>>
>>
>> Ok... take a shot at answering these and we'll see if that gives a bit
>> more insight into what's going on.
>>
>> Hope all is well,
>>
>> Eitan
>>
>> On Tue, Mar 30, 2010 at 3:57 PM, Dan Lazewatsky <
>> lazewatskyd at cse.wustl.edu> wrote:
>>
>>> Thanks for the response Eitan -
>>> I've created a map, and am trying to get an erratic to navigate in said
>>> map using nav_view. I set up the robot according the the nav robot setup
>>> tutorial, and when I run nav view I can see the map and set the robot's
>>> initial pose, but trying to set the goal doesn't seem to do anything. I get
>>> a printout from nav view saying "setting goal: Position(...)" but that's
>>> all.
>>>
>>> -Dan
>>>
>>>
>>> On 3/30/10 4:31 PM, Eitan Marder-Eppstein wrote:
>>>
>>> Dan,
>>>
>>> The wavefront package has fallen into a bit of disrepair as we favor our
>>> move_base package for autonomous navigation. If you're looking to run some
>>> autonomous navigation demos, check out the move_base_stage package instead
>>> of the 2dnav_stage package. The 2dnav_stage package will probably be removed
>>> in the near future to save people the confusion.
>>>
>>> Hope this helps,
>>>
>>> Eitan
>>>
>>> On Tue, Mar 30, 2010 at 12:07 PM, Dan Lazewatsky <
>>> lazewatskyd at cse.wustl.edu> wrote:
>>>
>>>> Hi all - I'm having some trouble using wavefront. When I try to start it
>>>> I get this:
>>>>
>>>> robotics at tears$ rosrun wavefront wavefront
>>>> terminate called after throwing an instance of 'ros::InvalidNameException'
>>>>   what():  Using ~ names with NodeHandle methods is not allowed.  If you want to use private names with the NodeHandle interface, construct a NodeHandle using a private name as its namespace.  e.g. ros::NodeHandle nh("~");  nh.getParam("my_private_name"); (name = [~dist_eps])
>>>> /home/robotics/ros/ros/bin/rosrun: line 35: 15562 Aborted                 $exepath "$@"
>>>>
>>>> Granted, I don't know what the right way to use wavefront since the
>>>> documentation is a bit spotty.
>>>>
>>>> Any ideas would be appreciated.
>>>>
>>>> Thanks,
>>>> -Dan
>>>>
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