RobLAX is a differentiable rigid body physics engine with contact1constraints that can assists various model-based methods. RobLAX is written in JAX and implements environments and model-base algorithm using jbdl. A render and urdf parser also included to extend to more realistic robotic application.

RobLAX also includes a suite of learning algorithms that train agents in seconds to minutes:

• Baseline learning algorithms such as PPO, SAC.
• An new actor-critic mbrl algorithm, Model-based Reinforcement Learning

Implement an actor-critic mbrl algorithm. Guo Ye, Qinjie Lin, Tim Lau, Zhaoran Wang, Han Liu.

Control the cartpole using manually calculated forward dynamics. Training converges at very fast speed(first two episodes). The cartpole can keep upright for 200 timesteps.

Training time takes 2 hours for 100 episodes on MAC. Can't tell any convergence from loss graph. The cartpole can keep upright for 57 timesteps.

python examples/cartpole_NN_rbdl.py

A 7 link arm robot contains 6 joints. The first base_link to arm_link_0 fixed joint will be interpreted as prismatic joint (rbdl index 1) by rbdl. The remaining 5 joints are revolute joints (rbdl index 0).

python examples/arm_NN_rbdl.py

The goal is to reach a fixed pose (keep second-to-last joint 90 degrees), with only 20 episodes of training, it can reach the goal within 10cm.

This is a quadrupedal robot(UNITREE) rendered using a pre-generated trajectory.

python examples/quadrupedal_NN.py

The goal is to lift front-left and hid-right leg 90 degrees, with around 200 episodes, robot can reach the goal.

Run on Magics Cluster

1. launch an ubuntu18 instance with tag cuda11.2
2. Install miniconda

   wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh
   

3. create env and install dependencies

   pip install -r requirements.txt
   #upgrade jaxlib to cuda11 version
   pip install --upgrade jax jaxlib==0.1.61+cuda111 -f https://storage.googleapis.com/jax-releases/jax_releases.html
   #enable GL 
   export MESA_GL_VERSION_OVERRIDE=4.3
   export PYTHONPATH=$PYTHONPATH:$PWD
   XLA_FLAGS=--xla_gpu_cuda_data_dir=/usr/local/cuda-11.2 python examples/cartpole_NN.py
   

If you would like to reference Roblax in a publication, please use:

@software{roblax2021github,
  author = {Guo Ye, Qinjie Lin, Tim Lau, Zhaoran Wang, Han Liu},
  title = {Roblax - A Fully Differentiable Rigid Body Simulator for Robotic Control},
  url = {http:https://github.com/michaelyeah7/roblax},
  version = {0.1.4},
  year = {2021},
}