Because the Stewart platform is a closed loop manipulator, the description was written in SDF rather than URDF. However, ROS does not support SDF by default, so a plugin was written to make the joints in Gazebo visible to ROS.
Here is a link to an in-progress generalized version of this plugin: https://github.com/daniel-s-ingram/ros_sdf.
Clone this repo to your catkin workspace src directory and build it:
cd ~/your_catkin_ws_src_path/
git clone https://github.com/daniel-s-ingram/stewart.git
catkin build stewart
source ~/your_catkin_ws/devel/setup.bash
To build the plugin:
cd plugin
mkdir build
cd build
cmake ../
make
Create the SDF file from the ERB template:
cd ../../sdf/stewart/
erb model.sdf.erb > model.sdf
Now, to launch the package:
roslaunch stewart stewart.launch
Note: The package currently expects a Dualshock 3 or 4 controller to be connected via USB.
The left analog stick translates in x and y. R2 increases z and L2 decreases z. The right analog stick rotates around the x and y axes (roll and pitch). R1 and L1 should increase and decrease yaw, respectively, but this isn't yet working for some reason.x