RTD PyBullet

Running RTD (Autonomous Reachability-based Manipulator Trajectory Design) in various platforms and simulate in pybullet, and create rendered animation.

Installation

It would be a good idea to install the python code in a virtual environment using using either conda or venv.

This installation assumes that you have correctly compiled armour's dependencies, which includes ipopt.

External Dependencies

rtd-pybullet has a number of dependencies. To generate nice visuals, you'll need Blender:

• blender
• pybullet-blender-recorder

There are also a number of python dependencies that can be installed by

 pip install -r requirements.txt

Included as submodules

• zonopy
• armour

Install the Blender plugin on Ubuntu

Make sure Blender is installed first. Then install the blender plugin:

sudo snap install blender --classic

Look at the Blender documentation for installing plugins on Windows or MacOS.

Install rtd-pybullet

git clone https://github.com/roahmlab/rtd-pybullet
cd rtd-pybullet
git submodule update --init --recursive
pip install -e .

Install zonopy

cd rtd-pybullet/zonopy
pip install -e .

Build ARMOUR

cd armtd-dev/cuda-dev/PZsparse-Bernstein/build
cmake ..
make

If the above doesn't work, there might be an issue with using Pybind11 as a submodule. You can get around this by installing it using pip.

We need to add the path to PYTHONPATH so that python can find the pybind module created by CMake.

export PYTHONPATH=$PYTHONPATH:$PWD

Examples

ARMOUR examples

Go to scripts/ and run test_bullet_planner.py to see what happens.

Zonopy examples

Go to scripts/ and run test_zonopy.py to see what happens.

Rendering trajectory and zonotopes (this needs update)

I. Running zonopy simulation and record data

Zonopy environment will generate an obstacle avoidance task, where a Kinova arm starts from a random position moves towards a random goal positions, with random obstacles around. Run scripts/test_zonopy.py to see what happens.

II. Save the reachable sets as mesh files

In order to visualize the reachable sets in Pybullet and in Blender, it has to be saved as mesh files so that they can be imported. Use MATLAB to run zonotope/FO2stl_zonopy.m will save those reachable sets as convex set in the format .stl. Don't forget to change folder.

III. Convert mesh files to urdf

Since the pybullet_blender_recorder works the best with .urdf format, we can convert those files to .urdf first. This process is done using pymeshlab and object2urdf. These packages make things easy. Running utils/stl2obj2urdf.py will do the job.

IV. Running the pre-computed trajectories in Pybullet

The pre-computed trajectories are discrete time and are assumed to be perfect tracking. We can track the trajectories using Pybullet with much smaller time step and real physics. The Pybullet environment is set up in here. Run scripts/bullet_zonopy_obstacle_avoidance.py to see the Pybullet simulation. In the mean time, the motions of the arm and the reachable sets are saved as .pkl files.

V. Render animation using Blender

With all the .pkl files, it is easy to do the rendering by importing them to Blender. Check out the instructions here.

TODO

• Improve the installation instructions
• Remove ARMOUR and zonopy as submodules