Real-Time Physics Simulation Forum

Re: URDF model falls through the ground

2020-01-23T12:50:19+00:00

Now I have still another challenge: The model keeps swinging back and forth. If you are interested, I have opened a new
post here: viewtopic.php?f=24&t=12852&p=42591#p42591

Statistics: Posted by simont — Thu Jan 23, 2020 12:50 pm

Re: URDF model falls through the ground

2020-01-23T10:38:31+00:00

Hi, I used this script below. This script is working similar as this one: https://github.com/andreasBihlmaier/pysdf

I'm not sure why your joints aren't working. How exactly did you generate the URDF?

Code:

#!/bin/bashsource catkin_ws/devel/setup.bashif [ ! -d "$2" ]; then  mkdir $2fiend_without_slash() {  str="$1"  i=$((${#str}-1))  last_char="${str:$i:1}"  if [ $last_char == "/" ]; then    echo "${str%?}"  else    echo "$str"  fi}src=$(end_without_slash "$1")esc_src=$(echo "$src" | sed -e 's/[\/&]/\\&/g')dst=$(end_without_slash "$2")esc_dst=$(echo "$dst" | sed -e 's/[\/&]/\\&/g')sdf=$(find "$src" -name "*.sdf")meshes="$src/meshes/CAD/"MESH_WORKSPACE_PATH=$meshes rosrun pysdf sdf2urdf.py "$sdf" "$dst/model.xml" --no-prefixsed -i "s/\(package:\/\/\)$esc_src\/\(meshes\/CAD\)/\1$esc_dst\/\2/g" "$dst/model.xml"cp -r "$src/meshes" "$dst"

For the transformation I execute this command:

$ ./sdf_to_urdf

Statistics: Posted by simont — Thu Jan 23, 2020 10:38 am

Re: URDF model falls through the ground

2020-01-23T10:09:07+00:00

Wow, amazing, this is actually working!! Thankyou!

Hi,

All components within the same URDF model have collision with each other disabled by default. The easiest way to get ground collision is to load the ground plane in as a separate model.
Code:
import pybullet_datap.setAdditionalSearchPath(pybullet_data.getDataPath())planeID = p.loadURDF("plane.urdf")

Statistics: Posted by simont — Thu Jan 23, 2020 10:09 am

Re: URDF model falls through the ground

2020-01-19T20:52:53+00:00

I'm not sure why your joints aren't working. How exactly did you generate the URDF?

Statistics: Posted by LocknutBushing — Sun Jan 19, 2020 8:52 pm

Re: URDF model falls through the ground

2020-01-19T20:44:59+00:00

Hi,

All components within the same URDF model have collision with each other disabled by default. The easiest way to get ground collision is to load the ground plane in as a separate model.

Code:

import pybullet_datap.setAdditionalSearchPath(pybullet_data.getDataPath())planeID = p.loadURDF("plane.urdf")

Statistics: Posted by LocknutBushing — Sun Jan 19, 2020 8:44 pm

Re: URDF model falls through the ground

2020-01-23T10:41:09+00:00

Hi, i have the following progress:

I put a baseplate (ground) into the model and connected the ground with the base with a fixed joint like you can see below. Now the base part won't fall
down, but the other parts still fall down. So it seems like the connections (joints) between the parts are not correct. Any ideas?

Code:

Statistics: Posted by simont — Thu Dec 12, 2019 9:48 am

URDF model falls through the ground

2020-01-23T10:40:34+00:00

Dear all, I have the below URDF file.

This is a description for a inverse pendelum robot which I want to train in a simulation with AI. When I load this file with pybullet for the training, it falls down through the ground and won't stop falling.

Has anybody an idea what could be wrong with the URDF file?

If there are missing some important information please let me know.

Thanks a lot for your help guys!

__________________________________________________________

Code:

Statistics: Posted by simont — Mon Dec 09, 2019 8:54 am