urdf to lagrangian equations of motion

edit

Here is a review of the libraries I am aware of. I hope it will help you make your choice!

Robotics algorithms

• Forward (or direct) geometry: from joint configuration to body position,
• Forward (or direct) kinematics: from joint velocity to body velocity,
• Inverse kinematics: from body velocity to joint velocity,
• Forward (or direct) dynamics: from forces applied on a body compute the body acceleration,
• Inverse dynamics: from body accelerations compute forces applied by the joints (RNEA).

For any of these algorithms, one may support or not:

• floating-base (through the addition of a free-flyer joint as the root joint of the model)
• particular structures such as trees (instead of chains) and closed-loops,
• external forces (for dynamics related algorithms). For instance, it is useful to take into account external disturbances during motion.

More information:

• Robot Dynamics (Scholarpedia)

Bullet (>= 2.82 / NEW)

Bullet Collision Detection & Physics SDK

Bullet is a Collision Detection and Rigid Body Dynamics Library. The Library is Open Source and free for commercial use, under the ZLib license.

Algorithms:

• Geometry: unknown
• Kinematics: unkown
• Dynamics: forward, inverse

Supported joints:

• 1-DOF revolute and prismatic joints

Features:

• License: ZLib
• Underlying matrix library: none, uses its own types,
• Frame representation: rotation matrix and translation vector,
• Online model edition: unknown,
• Tree support: yes,
• Floating base support: yes,
• URDF loading: NO

Links:

• Homepage
• API

KDL (Orocos)

The Kinematics and Dynamics library used by ROS core packages. Notably the robot_model one.

Algorithms:

• Geometry: direct
• Kinematics: direct, inverse
• Dynamics: inverse

Supported joints:

• 1-dof: revolute (X or Y or Z), prismatic (X or Y or Z)

Features:

• License: LGPL
• Underlying matrix library: none, uses its own types,
• Frame representation: rotation matrix and translation vector,
• Online model edition: yes,
• Tree support: NO,
• Floating base support: NO (only 1-dof joints),
• URDF loading: yes, separate ROS package kdl_parser, read only.

Links:

• Homepage
• API

Metapod

Metapod is a meta-programming dynamics computation library. The objective is to achieve high efficiency by assuming the robot model is known at compile-time. By doing so and by relying on advanced C++ techniques, dynamic allocation can be totally avoided and the compiler can achieve optimization that would not be possible in any other case.

Algorithms:

• Geometry: Direct[1]
• Kinematics: Direct[1]
• Dynamics: Inverse

[1] Those two algorithms are currently bound to the RNEA algorithm which means it is not possible currently to compute these quantities without computing the dynamics information.

Supported joints:

• 1-dof: revolute (X or any arbitrary axis)
• 6-dof: free-floating (three translation, three rotation)

Features:

• License: LGPL3
• Underlying matrix library: Eigen,
• Frame representation: spatial algebra (rotation matrix and translation vector),
• Online model edition: NO,
• Tree support: yes,
• Floating base support: yes,
• URDF support: yes, experimental, read only[1].

[1] This Python script lives as a specific branch of robot_model_py for now. Due to Metapod specific design, loading an URDF model means in this context generating a C++ file which then will be compiled to use the robot-specific dynamic algorithm (RNEA).

Links:

• Homepage

OpenRAVE [C++, Python]

This motion planning library is able to provide kinematics and dynamics computation ... (more)