RigidBodyDynamics

RigidBodyDynamics implements various rigid body dynamics and kinematics algorithms.

Design features

Some of the key design features of this package are:

pure Julia implementation, enabling seamless support for e.g. automatic differentiation using ForwardDiff.jl and symbolic dynamics using SymPy.jl.
easy creation and modification of general rigid body mechanisms (including basic URDF parsing).
extensive checks that verify that coordinate systems match before computation, with the goal of making reference frame mistakes impossible
flexible caching of intermediate results to prevent doing double work
fairly small codebase and few dependencies
singularity-free rotation parameterizations

Functionality

Current functionality of RigidBodyDynamics includes:

kinematics/transforming points and free vectors from one coordinate system to another
transforming wrenches, momenta (spatial force vectors) and twists and their derivatives (spatial motion vectors) from one coordinate system to another
relative twists/spatial accelerations between bodies
kinetic/potential energy
center of mass
geometric/basic/spatial Jacobians
momentum
momentum matrix
momentum rate bias (= momentum matrix time derivative multiplied by joint velocity vector)
mass matrix (composite rigid body algorithm)
inverse dynamics (recursive Newton-Euler)
dynamics
simulation, either using an off-the-shelf ODE integrator or using an included custom Munthe-Kaas integrator that properly handles second-order ODEs defined on a manifold.

Closed-loop systems (parallel mechanisms) are supported, with optional Baumgarte stabilization of the loop joint constraints. Support for contact is very limited (possibly subject to major changes in the future), implemented using penalty methods.

Installation

Installing Julia

Download links and more detailed instructions are available on the Julia website. Downloading Julia 0.6, the latest stable release at the time of writing, is currently recommended. However, RigidBodyDynamics.jl has already been updated to work with the latest 0.7 nightly versions, and future versions will exclusively support Julia 0.7.

Warning

Do not use apt-get or brew to install Julia, as the versions provided by these package managers tend to be out of date.

Installing RigidBodyDynamics

To install the latest tagged release of RigidBodyDynamics, start Julia and enter Pkg mode by pressing ], and then simply run

add RigidBodyDynamics

To check out the master branch and work on the bleeding edge (generally, not recommended), additionally run

develop RigidBodyDynamics

About

This library was inspired by IHMCRoboticsToolkit and by Drake.

Most of the nomenclature used and algorithms implemented by this package stem from the following resources:

Murray, Richard M., et al. A mathematical introduction to robotic manipulation. CRC press, 1994.
Featherstone, Roy. Rigid body dynamics algorithms. Springer, 2008.
Duindam, Vincent. Port-based modeling and control for efficient bipedal walking robots. Diss. University of Twente, 2006.

Related packages

MeshCatMechanisms.jl - 3D Visualization of mechanisms and URDFs using MeshCat.jl and RigidBodyDynamics.jl
RigidBodySim.jl - simulator built on top of RigidBodyDynamics.jl
MotionCaptureJointCalibration.jl - kinematic calibration for robots using motion capture data, built on top of RigidBodyDynamics.jl
RigidBodyTreeInspector.jl - 3D visualization of RigidBodyDynamics.jl Mechanisms using Director.

Joints

Rigid bodies

Mechanisms

MechanismState

Algorithms

Benchmarks

Citing this library

@misc{rigidbodydynamicsjl,
 author = "Twan Koolen and contributors",
 title = "RigidBodyDynamics.jl",
 year = 2016,
 url = "https://github.com/JuliaRobotics/RigidBodyDynamics.jl"
}