Gazebo | Ignition | Community
Ask Your Question

graffy's profile - activity

2020-12-04 07:59:50 -0500 received badge  Famous Question (source)
2018-10-11 09:49:43 -0500 received badge  Famous Question (source)
2018-10-11 09:49:43 -0500 received badge  Notable Question (source)
2018-10-11 09:49:43 -0500 received badge  Popular Question (source)
2018-07-28 10:19:49 -0500 received badge  Famous Question (source)
2018-07-28 10:19:49 -0500 received badge  Notable Question (source)
2017-08-23 14:05:51 -0500 received badge  Famous Question (source)
2017-08-23 14:05:51 -0500 received badge  Notable Question (source)
2017-08-23 14:05:51 -0500 received badge  Popular Question (source)
2017-05-27 04:23:33 -0500 received badge  Famous Question (source)
2017-03-24 14:53:56 -0500 received badge  Famous Question (source)
2017-03-05 10:33:58 -0500 received badge  Famous Question (source)
2017-02-22 02:30:06 -0500 received badge  Notable Question (source)
2017-02-20 09:54:41 -0500 asked a question Gazebo constantly overflows angular velocities

Hello,

I'm running into a problem reproducing drone physics (using the Hector quadrotor model). Trying to tune it frequently produces angular velocities that are NaN.

I've read that Gazebo seems to have a high sensitivity to inputs for models with low mass, so this is a frequent problem.

In reality, something can only rotate so fast. Is there a way to constrain the angular velocity to prevent NaNs, so the simulation remains viable? Or some way to test and ensure applied forces / torques don't trigger this cascade?

2017-02-14 05:51:45 -0500 received badge  Popular Question (source)
2017-02-13 14:01:30 -0500 received badge  Famous Question (source)
2017-02-13 14:01:30 -0500 received badge  Notable Question (source)
2017-02-13 14:01:30 -0500 received badge  Popular Question (source)
2017-02-12 22:13:42 -0500 answered a question Compiling sdformat on Win10

I managed to build SDFormat, but only after creating my own VC++ project and building the source from there. Interestingly, it seems that the problem was that the x64 boost libs were incompatible with the chosen architecture for SDFormat. Not sure what happened, but I managed to compatible 64-bit SDFormat against the latest boost libs (1.63.0) relatively easily once I rolled my own project.

Gazebo appears to be giving me the same grief, so I suspect I will have to take the same approach to getting it built.

2017-02-10 20:20:53 -0500 asked a question Compiling sdformat on Win10

Somewhat reluctant to ask, but I've encountered an issue building sdformat on Win10.

I'm building the project using VS2015 (following the gazebo tutorial for VS2013). The biggest trick was building boost 1.56.0 under 2015. But once I generated the libs, I managed to get SDFormat's cmake to pick them up during configuration.

The problem comes with building. That is, when I run NMake, it fails to link the sdf.dll because it's looking for the boost VS2013 libraries. Looking through the .obj files, there's four of them in sdformat that rely on boost libraries. Each one has a /DEFAULTLIB declaration that calls out the boost 2013 libraries (e.g. libboost_filesystem-vc120-mt-1_56.lib). This is what causes the error.

From what I can tell, /DEFAULTLIB occurs for certain compiler switches and #prgama comment(libname) declarations in code. Neither one seems to be the cause here.

I have searched for anything that might be hardcoding this reference into the SDF .obj files, but have come up empty.

Is there any wisdom regarding approaching Windows builds of Gazebo? I know others have managed to get it to work, but I suspect they were using VS2013, which, unfortunately, is not an option for me...

2017-02-10 19:24:06 -0500 asked a question Status update on Gazebo in Windows?

Any status update on a Windows build for gazebo? As I poke through various forum threads, build from source appears difficult at best...

2017-01-22 14:31:07 -0500 received badge  Notable Question (source)
2017-01-17 12:34:59 -0500 received badge  Self-Learner (source)
2017-01-17 12:34:59 -0500 received badge  Teacher (source)
2017-01-15 19:55:49 -0500 answered a question Building gazebo plugins with eclipse

I'm not really sure why the errors occurred, but following the tutorial here on integrating CMake with Eclipse was a big help:

http://johnnado.com/use-cmake-with-ec...

It may have been also the need to specify the compiler switch -std=c++11 under the compiler options in the C++ preprocessor provider settings in project properties.

In any case, I eventually got it to compile and run well, and have since set up several other projects with no issue.

2017-01-14 09:40:16 -0500 received badge  Notable Question (source)
2017-01-13 16:52:36 -0500 received badge  Popular Question (source)
2017-01-11 19:08:13 -0500 asked a question Low quality physics in gazebo

Hello,

I'm trying to tweak gazebo's physics to support higher-speed simulation times. I'm starting with several UAVs (about 40) and I've managed to get fairly good speed out of the simulation by increasing the max step size and setting the world friction values to zero. (mu / mu2 under ODE)

The one issue I can't overcome is that when I start the sim, as I add UAVs, they bounce incessantly on the ground plane because the physics updates are too low to resolve the forces. I'd like to be able to use "collide_without_contact" to disable contact forces upon collision, which (I presume) would take care of this issue. Of course, the UAVs then just simply fall through the ground plane.

I really only need low-quality physics to fly the UAVs - basically just gravity and collision detection are what's really required.

Any tips or pointers on how I can do a better job setting up the environment? At this point, I'm just thinking of auto-spawning the UAVs and fixing their pose on the ground plane until they're given orders to fly (shouldn't be too hard to do with a plugin if I'm correct).

2017-01-03 22:47:36 -0500 received badge  Popular Question (source)
2017-01-03 19:39:55 -0500 received badge  Notable Question (source)
2017-01-01 22:48:40 -0500 received badge  Popular Question (source)
2017-01-01 06:18:19 -0500 received badge  Enthusiast
2016-12-31 12:01:19 -0500 asked a question Gazebo and bullet3 / other GPU options

Hello,

I was wondering if there's any status on implementing bullet3 into Gazebo? I know it's a feature request that's pretty popular, but I was curious if there's any anticipated timeframe for it to be integrated?

To the point, I've tried building the experimental gazebo6 / bullet3 release that's about a year and a half old, but I've encountered a linking error I can't seem to resolve. In any case, I'd rather not rely on an old build of Gazebo.

That actually raises another question: Are there any robotics simulators out there that support GPU-accelerated physics? In the open source realm, it doesn't look like anything does, but I'm not well-versed in robotics sims...

2016-12-29 08:29:14 -0500 received badge  Popular Question (source)
2016-12-23 22:52:31 -0500 asked a question Eclipse generates odd build errors on plugin tutorial

Hello,

I've been setting up Eclipse to use as my IDE for developing Gazebo plugins.

I've been working through the contact sensor tutorial and have had a problem (similar to what I've seen on other tutorials).

Specifically, the following lines in the implementation file (.cc) generate respective errors:

code:

GZ_REGISTER_SENSOR_PLUGIN(PluginContact)

error:

The type 'gazebo::PluginContact' must implement the inherited pure virtual method 'gazebo::SensorPlugin::Load'

code:

void PluginContact::Load(sensors::SensorPtr _sensor, sdf::ElementPtr _sdf)

error:

Member declaration not found

code (in OnUpdate() function):

contacts = this->parentSensor->Contacts();

error:

Method 'Contacts' could not be resolved

and

no matching function for call to 'gazebo::sensors::ContactSensor::ContactSensor(gazebo::msgs::Contacts)'

What's really confusing is that, despite these errors, it still builds the plugin. Running make form the command line does as well, with no errors reported.

The error with the plugin macro has to do with the Load() function, obviously. And a little playing around has me thinking it's the sdf::ElementPtr paramter that's the cause of the trouble with the missing function declaration.

But I'm really confused. I have no idea why Eclipse seems to think I have these major problems with my class definition, and yet it builds the file without issue.

I can try to ignore it, but if I really want to use Eclipse to do development, this will get to be a tedious problem, even if it doesn't prevent the project from building.

2016-12-22 17:43:18 -0500 received badge  Student (source)
2016-12-22 16:58:02 -0500 received badge  Editor (source)
2016-12-22 16:55:40 -0500 asked a question Building gazebo plugins with eclipse

Hello,

I'm trying to set up a gazebo plugin project under Eclipse. I'm using a simple example to try to make it work, but for some reason, it won't link against the SDFormat libararies.

I've set up the plugin and added the header files that are installed in my /user/include path, and the IDE picks them up just fine.

But, when I compile, it errors on public: void Load(physics::ModelPtr _model, sdf::ElementPtr _sdf);

The error is: 'ElementPtr’ in namespace ‘sdf’ does not name a type

I've provided paths to the SDFormat libraries (libsdformat.so, libsdformat.so.4, libsdformat.so.4.1.1), so it should see everything fine.

Compiling using the cmake / make process outlined in the tutorials works ok, bu tI really want to do this from an Eclipse environment.

Any tips?

The sample code:

#ifndef SONARLISTENER_H_
#define SONARLISTENER_H_

#include <gazebo/gazebo.hh>
#include <gazebo/physics/physics.hh>
#include <sdf/Element.hh>

namespace gazebo {

class SonarListener: public gazebo::ModelPlugin {
public:

    SonarListener();
    virtual ~SonarListener();

    public: void Load(physics::ModelPtr _model, sdf::ElementPtr _sdf);
};

}
2016-12-20 10:39:10 -0500 asked a question Using Hector Quadrotor with gazebo and a neural network

Hello,

I'm faced with trying to make a UAV fly in gazebo using machine learning. The project is a bit ambiguous, and I'm pretty unfamiliar with Gazebo / robotics / UAVs apart from a passing general knowledge.

That said, I've spent some time working with Gazebo and the tutorials. Writing plugins to do the job doesn't seem all that difficult, and I took a look at the controller code for the hector quadrotor for a clue on how to build that part.

That said, I still really have no idea how to get Hector working in gazebo using plugins (no ROS). I see that the source was built with ROS in mind, and I also see that the model/sensor files are of the type urdf.xarco, which is not the same as an sdf.

Maybe I don't really need Hector to do the job - with sophisticated enough controller code, I'm sure the simple quadrotor model in gazebo would be just fine. Still, it would be nice if there was a more direct example of running simulations in gazebo without ROS... Even better if it demonstrated how to drive a gazebo sim with an AI...

Anyway, grateful for any tips or suggestions...

Thanks.

Anyway, I'm continuing to dig and follow leads, but I was hoping maybe someone could point me to something helpful...