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Features

• Highly and easily configurable:

  • Mechanical backlash, structural deformation and motor inertia
  • Sensor noise, jitter and delay
  • External forces on frames (both impulse or via time-continuous callback)
  • Multi-robot simulation with interaction forces
  • Contact point and collision geometries (both primitives and meshes)
  • Discrete or continuous sensors and controller independently
  • Model uncertainties
  • User-defined internal dynamics
  • User-defined ground profile using an implicit function: f(x,y) = [z, vect_normal]

• Deterministic or non deterministic on demand, but still PERFECTLY REPEATABLE

• Designed for fast and efficient optimal control research:

  • Support optimized step-by-step simulation or full episode simulation
  • Python bindings providing API parity with C++
  • Log user-defined variables easily

• Efficient Python Interface:

  • C++ / Python shared pointers to avoid copy back-and-forth

• Fast:

  • No real-time reading/writing on hard drive (RAM only)
    • The log can be exported in HDF5 or binary on demand
  • No real-time 3D rendering by default
  • Atlas: ~80 real-time factor

• Highly parallelizable:

  • Thread safe (single process - single core)
  • Synchronous by default
  • No shared memory

• Light weight:

  • About 5 minutes to compile from sources
  • Pre-compiled binaries are less than 20mo

• Well-suited for Reinforcement Learning:

  • Fully compliant with OpenAI Gym API and any machine learning framework built on it

Limitations

• Collision with vertical surface is impossible
• No internal collision between links, only with the ground
• Partial support of generic collision between primitive shapes and meshes

Development status

• Open-source Jiminy core: stable
• Open-source Gym/Jiminy interface: stable
• Mock of a High-Level Controllers: none
• Modelling still to be improved:
  • Only "perfect" sensor data with noise/delay/jitter is available
    • No complementary filter for IMUs, no voltage to force converter for Force sensors...
  • Only "perfect" torque motor control:
    • No voltage-current to torque-velocity conversion. No response time.
  • No advanced transmission between motors and joints