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2023-03-23 09:21:10 -0500 received badge  Supporter (source)
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2023-03-22 19:18:52 -0500 commented answer Modfy a joints friction value deuring exacution

Archived version of the Bitbucket PR referenced in this answer can be found at: https://osrf-migration.github.io/gazebo

2022-09-16 12:28:37 -0500 received badge  Teacher (source)
2021-10-15 12:40:48 -0500 commented answer accuracy of gazebo simulation of arm vs real hardware

I haven't looked at that, looks interesting. Thanks!

2021-08-04 14:23:51 -0500 received badge  Notable Question (source)
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2021-06-23 02:40:27 -0500 edited answer Transfer libgazebo9-dev from Ubuntu to Windows

Can I download libgazebo9-dev on Ubuntu and then transfer those files to the windows side? No, the binary libra

2021-06-23 02:38:26 -0500 answered a question Transfer libgazebo9-dev from Ubuntu to Windows

Can I download libgazebo9-dev on Ubuntu and then transfer those files to the windows side? No, the binary libra

2021-05-25 19:41:22 -0500 commented answer Gazebo installer for Windows 10

Yes, I have the Robostack version of Gazebo 11.5.1 and ROS Noetic on Windows. https://medium.com/robostack/cross-platfo

2021-05-21 13:52:04 -0500 edited answer accuracy of gazebo simulation of arm vs real hardware

What else is missing? In theory, what other factors complicates the simulation such that it cannot realisticall

2021-05-21 13:51:20 -0500 edited answer accuracy of gazebo simulation of arm vs real hardware

What else is missing? In theory, what other factors complicates the simulation such that it cannot realisticall

2021-05-21 13:50:09 -0500 edited answer accuracy of gazebo simulation of arm vs real hardware

What else is missing? In theory, what other factors complicates the simulation such that it cannot realisticall

2021-05-21 13:40:44 -0500 edited answer accuracy of gazebo simulation of arm vs real hardware

What else is missing? In theory, what other factors complicates the simulation such that it cannot realisticall

2021-05-21 12:29:58 -0500 answered a question accuracy of gazebo simulation of arm vs real hardware

What else is missing? In theory, what other factors complicates the simulation such that it cannot realisticall

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2021-05-03 13:13:54 -0500 edited question Setting relative display size of link coordinate frames?

Setting relative display size of link coordinate frames? I'm currently on Gazebo 9 on Melodic and wonder if there's a wa

2021-05-03 13:13:39 -0500 asked a question Setting relative display size of link coordinate frames?

Setting relative display size of link coordinate frames? I'm currently on Gazebo 9 on Melodic and wonder if there's a wa

2021-03-06 22:06:29 -0500 answered a question How to improve gazebo simulation, increase fps , using WSL

I think WSL doesn't connect natively to the graphics hardware yet, so I don't think there's a ton you can do. https://

2021-02-28 21:05:52 -0500 received badge  Notable Question (source)
2021-02-24 18:09:31 -0500 commented answer Inaccurate ForceTorque Feedback When Using Joint::SetVelocity Interface

I think the force-torque unit test is perhaps here now? GitHub

2021-02-19 15:20:37 -0500 commented question Querying collision geometry primitives from ROS in Gazebo 9?

I'm passing some rosparams at launch to work around this for now ¯\_(ツ)_/¯ I thought about parsing the SDF but if it's n

2021-02-19 15:20:27 -0500 commented question Querying collision geometry primitives from ROS in Gazebo 9?

I'm passing some rosparams at launch to work around this for now ¯_(ツ)_/¯ I thought about parsing the SDF but if it's no

2021-02-17 17:49:25 -0500 commented answer How to disable gravity only for a specific model in Gazebo?

@th123 <turnGravityOff>1</turnGravityOff> (case-sensitive) is working for me in ROS Melodic. <turngravity

2021-02-17 17:24:17 -0500 commented answer How to disable gravity only for a specific model in Gazebo?

Yep I'm hitting this now too (ROS Melodic + Gazebo9) Related to https://github.com/osrf/sdformat/issues/71 ?

2021-02-17 17:21:59 -0500 commented answer How to disable gravity only for a specific model in Gazebo?

Yep I'm hitting this now too (ROS Melodic + Gazebo9)

2021-02-17 17:18:49 -0500 commented answer How to disable gravity only for a specific model in Gazebo?

Yep I'm hitting this now too.

2021-02-17 11:19:09 -0500 commented question Querying collision geometry primitives from ROS in Gazebo 9?

I guess perhaps it's better to use a minimal world and spawn URDF models with <gazebo> tags here so that the whole

2021-02-17 08:18:01 -0500 commented question Querying collision geometry primitives from ROS in Gazebo 9?

Same question, no answers: https://answers.gazebosim.org/question/26142/get-gazebo-geometry-information-of-objects/

2021-02-17 08:18:01 -0500 received badge  Commentator
2021-02-16 17:28:16 -0500 asked a question Querying collision geometry primitives from ROS in Gazebo 9?

Querying collision geometry primitives from ROS in Gazebo 9? Is there a way to query Gazebo from ROS to get the paramete

2021-02-11 08:43:13 -0500 marked best answer Properly making soft joints to world in Gazebo 9 + ROS Melodic

I'm trying to interact a position-controlled robot with "fixed" obstacles in its environment. In this case, they're a couple of floating spheres, "magically" fixed in space. I'm using default ros-melodic-desktop-full installations to do this, in this case Gazebo 9.13.1 on Windows.

With <static> obstacles and default constraint parameters, the robot "explodes" if it touches obstacles. This is reasonable behavior given the incompatible constraints of infinitely rigid object meets immovable object.

If I add some global constraint force mixing with <cfm> tags at world->physics scope, it stabilizes the simulation and makes the robot's contacts with the world understandable, but it also allows the joints to slide apart. This is also correct behavior from the standpoint of what CFM does, but it's not the desired behavior.

What I'd like to do is attach the floating spheres to the world frame using spring-dampers that are much softer than the robot joints, so that they easily slide out of the way if the robot collides without pulling the robot joints apart visibly.

I'm having a very hard time finding a correct and complete description on how to do this, partially because any suggestions are scattered across many years of SDF file format changes, unanswered ROS Answers and Gazebo Answers questions, and so on.

I have successfully held the spheres in place with fixed joints so they move a little with relaxed constraints. After a long time experimenting (because of lack of a complete example) I figured out I could put those joints in a nested <model> so I could write this "boundary condition" in my world file instead of the complex model file that defines the visual/inertial/collision geometry.

Now I'd like to soften the joints that hold the spheres in place. So I'm trying to set different <cfm> and <erp> values for the spheres' fixed joints, or maybe <implicit_spring_damper> or ... what? Everything I've tried has resulted in the spheres' displacements being the same order of magnitude as the robot's displacement.

image description

I still can't find a documentation source that's any more useful than http://sdformat.org/spec?elem=joint&v..., but that just kind of tells me which tags I might try, not how they fit together.

The image was captured using these settings for the red sphere:

<model name="soft_fixed_big_red">
  <include>
    <uri>model://big_red</uri>
    <name>red_sphere</name>
  </include>
  <joint name="bc" type="fixed">
    <parent>world</parent>
    <child>red_sphere::link</child>
    <physics>
      <ode>
        <implicit_spring_damper>1</implicit_spring_damper>
        <cfm>0.9</cfm>
        <erp>0.2</erp>
      </ode>
      <provide_feedback>true</provide_feedback>
    </physics>
  </joint>
  <pose>0.15 0.50 0.45 0 0 0</pose>
</model>

The spheres had mass properties like solid plastic when I started. I tried making them thin, extremely light spherical shells, which made it shakier but roughly similar in relative sphere and robot displacements.

At the world level (which contains the red and blue sphere models, ground plane, and sun), I have this:

<physics name ...
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2021-02-11 08:43:13 -0500 received badge  Scholar (source)
2021-02-11 08:42:18 -0500 commented answer Properly making soft joints to world in Gazebo 9 + ROS Melodic

Forgot the <physics><ode> tags around it.

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2021-02-10 23:25:56 -0500 commented answer kinematic links use case?

This answer was super helpful. I'll come back when I have enough karma to upvote. <kinematic> as a moveable bound

2021-02-10 20:35:18 -0500 commented answer Properly making soft joints to world in Gazebo 9 + ROS Melodic

It looks like <implicit_spring_damper> is not actually supported yet at least in the way I'm using it. When I star

2021-02-09 16:37:17 -0500 answered a question Properly making soft joints to world in Gazebo 9 + ROS Melodic

I solved this for 3DOF compliance on the red sphere with a chain of prismatic joints and links with <implicit_spring_

2021-02-09 15:26:04 -0500 commented question Properly making soft joints to world in Gazebo 9 + ROS Melodic

Serial joints now working correctly. Had the damping set too low on the second joint of the red sphere. Working okay no

2021-02-09 15:25:12 -0500 commented question Properly making soft joints to world in Gazebo 9 + ROS Melodic

Serial joints now working correctly. Had the damping set too low on the second joint of the red sphere, and a very high

2021-02-09 13:39:39 -0500 commented question Properly making soft joints to world in Gazebo 9 + ROS Melodic

I tried to add two prismatic joints in series with a light link in between and now the red sphere behaves correctly for

2021-02-08 07:50:24 -0500 commented question Properly making soft joints to world in Gazebo 9 + ROS Melodic

I'm chasing the wrong modeling paradigm here and I think I'm probably going to go with virtual cardboard boxes for anyth

2021-02-08 07:50:23 -0500 commented question Properly making soft joints to world in Gazebo 9 + ROS Melodic

<dynamics> tagged joints may be a partial solution, but very verbose to go to 6DOF springiness <joint name="

2021-02-08 07:50:21 -0500 asked a question Properly making soft joints to world in Gazebo 9 + ROS Melodic

Properly making soft joints to world in Gazebo 9 + ROS Melodic I'm trying to interact a position-controlled robot with "

2021-02-08 07:50:18 -0500 commented question How do I use ODE's ERP feature correctly to model an elastic joint?

How can I model a 1 DOF revolute joint with spring and damper via this method? Yes, I really want to know this too.

2021-02-08 07:50:16 -0500 commented question How do I use ODE's ERP feature correctly to model an elastic joint?

Have you made any progress on this? The joints however behave very differently now, seemingly having 6 DoF, allowing