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2019-08-28 03:48:35 -0600 commented answer Simple model always becomes unstable

Thanks! This works, but my complete model, with 31 revolute joints, still crashes in a similar fashion, even with iterat

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2019-08-14 05:54:53 -0600 commented question Simple model always becomes unstable

Note that there are no controllers here. I just start gazebo and the model in itself becomes unstable.

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2019-08-14 03:57:18 -0600 commented question Simple model always becomes unstable

Thanks for the reply. Please see the update.

2019-08-14 03:56:54 -0600 edited question Simple model always becomes unstable

Simple model always becomes unstable Hi list, I have a model with 5 revolute joints, nothing special. It is a kind of s

2019-08-13 05:13:56 -0600 asked a question Simple model always becomes unstable

Simple model always becomes unstable Hi list, I have a model with 5 revolute joints, nothing special. It is a kind of s

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2019-06-09 02:38:27 -0600 edited question Instabilities with ODE engine

Instabilities with ODE engine This actually is a follow up of still-runaway-simulations-in-gazebo. There I thought that

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2019-05-16 02:40:51 -0600 edited question Instabilities with ODE engine

Instabilities with ODE engine This actually is a follow up of still-runaway-simulations-in-gazebo. There I thought that

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2019-05-13 04:42:05 -0600 asked a question Instabilities with ODE engine

Instabilities with ODE engine This actually is a follow up of still-runaway-simulations-in-gazebo. There I thought that

2019-05-13 02:04:27 -0600 edited question Friction when using the DART engine

Friction when using the DART engine I have been forced to use the DART physical engine because ODE crashes with my model

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2019-05-10 07:33:45 -0600 asked a question Friction when using the DART engine

Friction when using the DART engine I have been forced to use the DART physical engine because ODE crashes with my model

2019-05-10 04:19:22 -0600 marked best answer Still runaway simulations in gazebo

Hello List,

UPDATED YET AGAIN: See 3rd update below!

I am having difficulties in getting stable behaviour with my simulated rowing boat. The model can be found on my github page in the boot3_description/urdf directory.

A simplified version can be found in the testing directory Please see crash.mp4 for how the simulation (and simulator) blows up.

Sometimes there is an error message like:

gzclient: /build/ogre-1.9-B6QkmW/ogre-1.9-1.9.0+dfsg1/OgreMain/include/OgreAxisAlignedBox.h:252: void Ogre::AxisAlignedBox::setExtents(const Ogre::Vector3&, const Ogre::Vector3&): Assertion `(min.x <= max.x && min.y <= max.y && min.z <= max.z) && "The minimum corner of the box must be less than or equal to maximum corner"' failed.

The model is crash_boot.xacro and for testing I use the (normally) generated crash_boot.sdf. The model now contains only 3 revolute joints. Playing around with friction and damping does not help.

What does help is reducing the max step size by a factor of 10. But it then becomes impractically slow, especially when using the full blown model with almost 40 joints.

Hopefully someone can help, as I am really stuck here.

UPDATE: Enforcing more limits as in

   <limit>
          <lower>-1.5</lower>
          <upper>0.5</upper>
          <effort>1</effort>
          <velocity>0.01</velocity>
        </limit>

seems to be completely ignored the model and gazebo crashes just the same!

2nd UPDATE: Getting a bit despondent here.

I can get it a bit better by increasing iterations in the solver, e.g. to 200 or 500. The testing model now works fine, but the complete (boot3) model now most of the time will be stable for some time (sometimes several minutes). But adding a few controllers to the joints makes it unstable again. But not by the controller itself, I am using very low values for pid.

The instability maybe comes from two or more joints connected directly together as in an elbow or shoulder using e.g.

 <link name="left_shoulder_psi_link">
    <inertial>
      <mass value="0.01"/>
      <origin rpy="0 0 0" xyz="0 0.0 0.0"/>
      <inertia ixx="0.000000167" ixy="0" ixz="0" iyy="0.000000167" iyz="0" izz="0.000000167"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0.0 0.0 0.0"/>
      <geometry>
        <box size="0.01 0.01 0.01"/>
      </geometry>
    </visual>
  </link>

So with no change in the origin.

If you pull the Rowing repository and then do

roslaunch boot3_gazebo control_boot_world.launch

you will see the simulated rower in gazebo. Starting the simulation (and the control via ros_control) will show the crashing fairly quickly.

The following shows that a simplified model does work ok.

roslaunch testboot_gazebo control_boot_world.launch

3rd UPDATE

After some help from gazebo/issues I now have a better simple example that still crashes! Please see this folder on my github page.

The video shows the usual form of crashing. Sometimes gazebo crashes entirely with the error mentioned above.

Simplifying it further makes is stable most of the time. For example removing the fixed_joint ... (more)

2019-05-10 04:19:17 -0600 commented answer Still runaway simulations in gazebo

Thanks! Installing the DART engine did the trick. I get some warnings, but it works perfectly for me. I first tried low

2019-05-01 03:29:12 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, UPDATED YET AGAIN: See 3rd update below! I am having difficulties in g

2019-05-01 03:27:45 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, UPDATED YET AGAIN: See 3rd update below! I am having difficulties in g

2019-04-10 07:22:12 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, UPDATED AGAIN: See latest update below! I am having difficulties in ge

2019-04-01 04:28:36 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, UPDATED: See update below! I am having difficulties in getting stable

2019-03-28 05:17:09 -0600 commented answer Still runaway simulations in gazebo

In a, late, response to your last comment: I do not apply any force to the joints. The model crashes by itself. Also in

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2019-03-14 05:35:01 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, UPDATED: I completely rewrote the question to make it more clear. I a

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2019-01-29 15:58:58 -0600 edited question Joints don't behave as they should.

Joints don't behave as they should. Hello list, I have a model with fixed, revolute and prismatic joints. During simula

2019-01-29 05:15:30 -0600 edited question Joints don't behave as they should.

Joints don't behave as they should. Hello list, I have a model with fixed, revolute and prismatic joints. During simula

2019-01-28 06:14:57 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, It's becoming a long story, please see my 4-th edit below. I am having

2019-01-28 04:40:59 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, It's becoming a long story, please see my 4-th edit below. I am having

2019-01-28 03:05:49 -0600 asked a question Joints don't behave as they should.

Joints don't behave as they should. Hello list, I have a model with fixed, revolute and prismatic joints. During simula

2019-01-20 08:41:38 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, After 2 months I still am struggling with this! Please see my third edi

2018-11-26 04:21:35 -0600 commented question Running Gazebo without being superuser

As a side note: why the sudo? I don't think that's advisable.

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2018-11-20 12:52:15 -0600 commented answer Still runaway simulations in gazebo

Please see my second edit.

2018-11-20 12:51:28 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, I am having difficulties in getting stable behaviour with my simulated

2018-11-13 11:58:53 -0600 commented answer Still runaway simulations in gazebo

Thanks, see my edit above. And also thanks for the links! I want to do experiments with rigging of race-shells, in order

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2018-11-13 10:48:23 -0600 edited question Still runaway simulations in gazebo

Still runaway simulations in gazebo Hello List, I am having difficulties in getting stable behaviour with my simulated