Sietse's profile - activity

overview network karma followed questions activity

2020-11-18 09:56:08 -0600	received badge	● Student (source)
2020-04-20 15:47:34 -0600	received badge	● Famous Question (source)
2020-04-20 15:47:34 -0600	received badge	● Notable Question (source)
2019-08-28 03:48:35 -0600	received badge	● Commentator
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
2019-08-27 12:49:58 -0600	received badge	● Famous Question (source)
2019-08-14 11:54:53 -0600	received badge	● Notable Question (source)
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.
2019-08-14 05:31:35 -0600	received badge	● Popular Question (source)
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
2019-06-09 02:38:27 -0600	received badge	● Associate Editor (source)
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
2019-05-19 05:23:00 -0600	received badge	● Famous Question (source)
2019-05-16 05:09:09 -0600	received badge	● Famous Question (source)
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
2019-05-16 02:37:48 -0600	received badge	● Notable Question (source)
2019-05-14 13:41:45 -0600	received badge	● Popular Question (source)
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
2019-05-12 21:39:28 -0600	received badge	● Popular Question (source)
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
2019-03-14 05:36:24 -0600	received badge	● Organizer (source)
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
2019-03-13 09:09:37 -0600	received badge	● Famous Question (source)
2019-02-01 02:54:29 -0600	received badge	● Notable Question (source)
2019-01-30 03:17:57 -0600	received badge	● Popular Question (source)
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.
2018-11-24 12:14:15 -0600	received badge	● Famous Question (source)
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
2018-11-13 11:58:23 -0600	received badge	● Notable Question (source)
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