54 lines
1.9 KiB
Markdown
54 lines
1.9 KiB
Markdown
# Python wrapper for RBDL
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This wrapper uses Cython to wrap RBDL in a Python module. The code requires
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C++11 features and must be compiled with the flags ```-std=c++11``` (or on
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older compilers: ```-std=c++0x```). It closely follows the C++ API. All
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functions are found in the module ```rbdl```, e.g.
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rbdl.ForwardDynamics (model, q, qdot, tau, qddot)
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computes the accelerations qddot of the forward dynamics for given model,
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q, qdot, tau.
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Arguments are all passed as reference and where possible, the wrapper
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avoids copying values, especially for larger matrices such as Jacobians,
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and joint-space inertia matrix.
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All functions have embedded signatures to ease the use from within IPython,
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e.g. ```rbdl.ForwardDynamics?``` shows required arguments for the function.
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# Highlights
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Wrappers for the following features are already implemented:
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* supports model creation from Python code
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* supports model loading from LuaModel and URDF
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* operates directly on raw numpy data for Jacobians and joint-space inertia
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matrix - no copying required!
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* direct access to almost all values of the Model structure
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* all functions of Dynamics.h are wrapped:
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- O(n) inverse dynamics via RNEA
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- O(n) forward dynamics via ABA
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- Coriolis term computation via simplified RNEA
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- computation of joint-space inertia matrix via CRBA
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* kinematic computations:
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- body <-> world transformations
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- body point positions, velocities, and accelerations, including their
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6-D counterparts
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- point Jacobians (translations)
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- 6-D Jacobians (angular and linear movement)
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- Spatial 6-D body Jacobians
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* model mass, Center of Mass (CoM), CoM velocity, centroidal angular momentum
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# Differences to the C++ API
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The wrapper function ```rbdl.CalcCenterOfMass``` has a scalar return value
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which is the mass of the model. Therefore the function does not use the
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mass parameter when calling it.
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# ToDo
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* wrapping of constraint sets, and contact dynamics
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* inverse kinematics
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* documentation
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