google-deepmind/mujoco_menagerie

Features

• Robot Model Libraries - Provides a curated collection of high-quality robot model files for humanoids, quadrupeds, and manipulators.
• Robot Model Repositories - Provides a curated set of pre-configured XML model definitions optimized for accurate dynamics and contact simulation.
• Hardware-Accelerated Simulations - MuJoCo runs physics simulations on GPUs and TPUs by utilizing XLA-compatible implementations.
• Multibody Dynamics Simulators - Utilizes generalized coordinates and optimization-based dynamics to simulate complex articulated multibody systems.
• Robotics Simulators - Provides standardized 3D assets and kinematic specifications for simulating diverse robot hardware and environments.
• Domain Randomizations - Varies physical properties across a batch of simulation worlds to improve sim-to-real generalization.
• Robotic Physics and Sensor Simulators - Simulates complex interactions between robots and objects within a physics-enabled environment.
• Physical Robot Specifications - Provides detailed kinematic and inertial parameters to reproduce real-world robot behavior in virtual environments.
• Robot Model Importers - Imports robot models from XML or binary files and compiles them into a simulation-ready format.
• Robotic Model Parsers - Compiles model specifications into a usable internal representation to initialize the simulation environment.
• Sensor and Actuator Drivers - Implements simulation models for motors, pneumatic cylinders, hydraulic systems, and biological muscles.
• Kinematic Joint Definitions - Implements degrees of freedom between bodies using free, ball, slide, or hinge joint types.
• Hierarchy Construction - Builds the physical hierarchy of the model using bodies, joints, and nested parent-child relationships.
• Mass Property Overriding - Allows manual specification of mass and diagonal inertia matrices to control physical behavior.
• Collision Detection - Identifies active contacts between geometric entities using GJK/EPA algorithms.
• Mechanical Joint Constraints - Implements degrees of freedom between bodies using free, ball, slide, or hinge joint types.
• Physics Solvers - Evolves the simulation state forward by computing physical interactions using configurable solvers.
• Articulated Body Simulators - Enforces equality constraints to connect bodies at anchor points or weld them together rigidly.
• Robot Model Format Converters - Parses and compiles robot model files between MJCF, URDF, MJB, and TXT formats.
• Simulation Loops - Advances the physical state using a numerical integrator and integrated control callbacks.
• Simulation Steppers - Computes the next state of the physical scene by stepping the simulation forward in time.
• 3D Geometry Import - Loads triangulated geometry from STL, OBJ, or MSH files to define visual and collision shapes.
• Actuator Modeling - Provides the ability to define components that apply forces to joints and bodies to drive simulated motion.
• Kinematics Simulators - Adds detailed kinematic attributes to joint primitives to describe body movement and rotation.
• Forward Dynamics Solvers - Computes the time-derivative of the system state, including accelerations and sensor data.
• Inverse Dynamics Solving - Determines the required joint torques to achieve specific accelerations for computed torque control.
• Kinematic Coordinate Frames - Converts positions and orientations between local, global, and center-of-mass coordinate systems.
• Constraint Solvers - Tunes numerical optimization algorithms and friction cone models to balance accuracy and performance.
• Constraint Force Optimization - Computes global constraint forces as the solution to a convex optimization problem.
• Physical Model Composition - Allows the creation of complex robot models by attaching bodies, frames, and specifications to one another.
• Kinematic Tree Representations - Organizes bodies and joints in a nested hierarchy to establish spatial relationships and degrees of freedom.
• Compute Graph Captures - MuJoCo records a sequence of kernel launches into a CUDA graph to reduce overhead during simulation steps.
• Parallel Trajectory Generation - Distributes environment interactions across multiple CPU cores to accelerate trajectory collection.
• Spatial Pose Management - MuJoCo returns the 3D position or unit quaternion orientation of a spatial frame.
• Physics Simulation - Configures global physics parameters such as gravity, wind, and timestep for the simulation environment.
• Deformable Mesh Simulation - Simulates 1D, 2D, or 3D flexible elements that preserve shape via passive constraint forces.
• Differentiable Physics Engines - Creates loop joints or mechanical couplings by defining differentiable scalar or vector functions.
• Parallel Simulations - Runs multiple physics worlds simultaneously across CPUs, GPUs, or TPUs using CUDA or JAX.
• Parallel Rendering - Generates pixel observations across multiple parallel simulation worlds using a hardware-accelerated batch renderer.
• Friction and Restitution Systems - Specifies explicit collision properties and anisotropic friction for specific pairs of geometries.
• Physical Environment Simulation - Sets global simulation options and compiler flags to control the physics environment.
• Mesh and Model Loading - Loads triangulated OBJ or STL files to define collision hulls and infer inertial properties.
• Electrical Actuator Simulation - Models electrical actuators with resistance, inductance, thermal dynamics, and cogging torque.
• Servo Positioning - Provides actuators that apply force based on position feedback gains and optional first-order filters.
• Muscle Actuator Modeling - Simulates muscle behavior using force-length-velocity curves and activation dynamics.
• Collision Filtering - Replaces default collision mask logic to determine which geometry pairs trigger collisions.
• Custom Collision Routines - Replaces built-in pairwise collision functions for specific geometry types to change how intersections are computed.
• Custom Actuator Dynamics - Allows the definition of custom activation dynamics, gains, and biases for user-defined actuators.
• Contact Pair Configuration - Explicitly defines contact pairs or excludes specific body pairs to override automated collision detection.
• Simulation State Vector Snapshotting - Stores a library of state vectors including joint positions and control inputs for simulation initialization.
• 3D Asset Managers - Supports the loading of various 3D mesh and scene formats including OBJ, STL, and USD.
• Simulation Island Partitioners - MuJoCo increases performance by partitioning degrees of freedom into independent disjoint sub-graphs solved in parallel.
• 3D Scene Exporters - Saves scenes and trajectories in USD format for high-quality rendering in external software.
• 3D Model Exporters - Transforms transient physics model definitions into persistent 3D file formats for long-term storage.
• Physical Material Properties - Defines surface and material properties to accurately control friction and restitution during collisions.
• Fixture Shape Definitions - Defines physical boundaries for primitive or mesh shapes to manage object collisions.
• Ray and Shape Casting - Calculates intersection distances between 3D lines and geometry surfaces to detect proximity.
• Equality Constraints - Creates mechanical couplings and loop joints by imposing differentiable equality constraints on bodies and joints.
• Cable Simulation Hierarchies - Simulates inextensible cables by expanding macros into chains of bodies connected by ball joints.
• Unilateral Constraints - Implements rotation and length limits for joints and tendons using range and margin parameters.
• Physics World Debugging Tools - Includes an interactive viewer for inspecting and testing the internal state of physical simulations.
• Simulation Tick Callbacks - Injects custom logic into the physics engine via global callbacks to modify behavior or define forces.
• Programmable Model Modification - Creates and modifies simulation models through a data structure that maps directly to XML definitions.
• Programmatic Model Editing - Programmatically creates and modifies robot models, including the addition of bodies, geoms, and meshes.
• Simulation Keyframe Management - Saves and restores snapshots of joint positions, velocities, and actuator states to reset the system.
• Interactive Simulations - Provides an interactive OpenGL window for model rendering, camera control, and sensor plotting.
• Simulation Logic Extensions - Inserts user-defined logic into the computational pipeline to implement custom sensors and actuators.
• Simulation Scene Composition - Composes complex scenes by including multiple XML files, allowing shared assets and reusable robot components.
• Simulation State Integration - Implements numerical integration methods to advance the simulation state over discrete timesteps.
• Soft Body Simulations - Calculates contact dynamics using a soft contact model to balance accuracy and efficiency.
• Multibody Scene Composition - References physics model files directly within larger 3D scenes using standard composition arcs.
• 3D Simulation Rendering - Provides 3D visualization of simulation models and decorative elements like contact points.
• Constructive Solid Geometry Kernels - Implements a system for building complex 3D objects by combining geometric primitives and height fields.
• OpenGL 3D Pipelines - Sets up an OpenGL context to generate images of simulations without displaying a window.
• Collision Shapes - Implements custom signed distance functions via plugins to define specialized collision shapes.
• Mesh-Based Collision Geometry - Attaches geometric primitives or meshes to bodies to determine their physical boundaries.
• Non-Convex Collision Handling - Implements custom collision logic to handle intersections for non-convex meshes.
• Signed Distance Field Representations - Specifies custom shapes using signed distance fields to enable mesh-free collision detection.
• Physics-to-USD Conversions - Transforms MJCF files into USD assets using specialized schemas to ensure faithful physical representation.
• USD Asset Importers - Loads 3D assets from USD files to define the geometry and physical properties of simulation objects.
• Force Limiting - Simulates hardware limitations by clamping control inputs or output forces at the actuator and joint levels.
• Biomechanical Simulations - Simulates muscle-tendon actuators using scaled length-velocity functions to approximate biological force production.
• Contact Parameter Tuning - Defines friction coefficients, margins, and priority rules to determine how colliding geometries interact.
• Control Law Implementations - Allows defining custom control and applied force vectors based on the current position and velocity.
• Signed Distance Fields - MuJoCo calculates the smallest signed distance between two geoms or along a ray from a camera.
• Parallelized Dynamics Sampling - MuJoCo executes multiple forward or inverse dynamics calls across a thread pool using private data structures.
• Parallel Scene Simulations - Provides an interactive viewer to observe multi-world simulations in real-time.
• Interactive Dynamics Probing - Manipulates body poses or applies external forces and torques in real-time to probe system dynamics.
• Joint Jacobian Computations - Provides efficient computation of state-transition and control-transition Jacobians for robotic dynamics.
• Live Simulation Model Recompilation - Updates an active model and its simulation state without restarting to allow structural changes.
• Model Serialization - Saves compiled model specifications as human-readable XML files or strings.
• Dynamic Geometry Models - Creates 3D strings with wrapping and via-point constraints to simulate mechanical coupling and pulleys.
• Nonlinear Optimization Solvers - MuJoCo solves sequential quadratic programs using a nonlinear least squares optimizer.
• Parallel Computation Thread Pools - MuJoCo creates a thread pool with a specified number of worker threads to parallelize simulation computations.
• Nonlinear Force Models - Specifies nonlinear stiffness and damping for joints and tendons using polynomials.
• Robot Model Composition - Provides the ability to inject subtrees of bodies from one model asset into another to reuse complex robot components.
• Robotic Sensor Simulations - MuJoCo measures scalar and vector data from actuators and joints to provide real-time feedback.
• Simulation Interest Sites - Defines specific locations on bodies to serve as mounting points for sensors or tendon via-points.
• Synthetic Sensor Simulation - MuJoCo generates readings from touch, IMU, force-torque, and rangefinder sensors.
• Tendon and Cable Simulations - Simulates cables by creating paths that wrap around obstacle geometries and pass through specific sites.
• State Snapshots - Stores tensor values of the simulator state at intervals to capture and reconstruct motion.
• Execution Pipelines - Organizes simulation logic into an execution pipeline that can be reconfigured via flags and callbacks.
• Runtime Parameter Tuning - Updates real-valued parameters of a compiled model at runtime to change physics behavior without recompilation.
• Physics - Executes custom control logic at the latest possible point in the simulation pipeline for real-time state access.
• Simulation Engine Plugins - Installs Python or native C callbacks as plugins to modify the computation pipeline for custom components.
• Offscreen Framebuffer Managers - Outputs visual data to a headless framebuffer for synthetic computer vision in cloud environments.
• USD Physics Exporters - Converts physics simulation assets into Universal Scene Description format using a Python-based exporter.

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