Functions
RBDL_DLLAPI void	InverseDynamics (Model &model, const Math::VectorNd &Q, const Math::VectorNd &QDot, const Math::VectorNd &QDDot, Math::VectorNd &Tau, std::vector< Math::SpatialVector > *f_ext=NULL)
	Computes inverse dynamics with the Newton-Euler Algorithm. More...

RBDL_DLLAPI void	NonlinearEffects (Model &model, const Math::VectorNd &Q, const Math::VectorNd &QDot, Math::VectorNd &Tau, std::vector< Math::SpatialVector > *f_ext=NULL)
	Computes the coriolis forces. More...

RBDL_DLLAPI void	CompositeRigidBodyAlgorithm (Model &model, const Math::VectorNd &Q, Math::MatrixNd &H, bool update_kinematics=true)
	Computes the joint space inertia matrix by using the Composite Rigid Body Algorithm. More...

RBDL_DLLAPI void	ForwardDynamics (Model &model, const Math::VectorNd &Q, const Math::VectorNd &QDot, const Math::VectorNd &Tau, Math::VectorNd &QDDot, std::vector< Math::SpatialVector > *f_ext=NULL)
	Computes forward dynamics with the Articulated Body Algorithm. More...

RBDL_DLLAPI void	ForwardDynamicsLagrangian (Model &model, const Math::VectorNd &Q, const Math::VectorNd &QDot, const Math::VectorNd &Tau, Math::VectorNd &QDDot, Math::LinearSolver linear_solver=Math::LinearSolverColPivHouseholderQR, std::vector< Math::SpatialVector > f_ext=NULL, Math::MatrixNd H=NULL, Math::VectorNd *C=NULL)
	Computes forward dynamics by building and solving the full Lagrangian equation. More...

RBDL_DLLAPI void	CalcMInvTimesTau (Model &model, const Math::VectorNd &Q, const Math::VectorNd &Tau, Math::VectorNd &QDDot, bool update_kinematics=true)
	Computes the effect of multiplying the inverse of the joint space inertia matrix with a vector in linear time. More...

Detailed Description

Function Documentation

◆ CalcMInvTimesTau()

RBDL_DLLAPI void RigidBodyDynamics::CalcMInvTimesTau	(	Model &	model,
		const Math::VectorNd &	Q,
		const Math::VectorNd &	Tau,
		Math::VectorNd &	QDDot,
		bool	update_kinematics = `true`
	)

Computes the effect of multiplying the inverse of the joint space inertia matrix with a vector in linear time.

Parameters

model	rigid body model
Q	state vector of the generalized positions
Tau	the vector that should be multiplied with the inverse of the joint space inertia matrix
QDDot	vector where the result will be stored
update_kinematics	whether the kinematics should be updated (safer, but at a higher computational cost)

This function uses a reduced version of the Articulated Body Algorithm to compute:

$\ddot{q} = M(q)^{-1} \tau$

for given $q$ and $\tau$ in $O(n_{\textit{dof}})$ time.

Note: When calling this function repeatedly for the same values of Q make sure to set the last parameter to false as this avoids expensive recomputations of transformations and articulated body inertias.

◆ CompositeRigidBodyAlgorithm()

RBDL_DLLAPI void RigidBodyDynamics::CompositeRigidBodyAlgorithm	(	Model &	model,
		const Math::VectorNd &	Q,
		Math::MatrixNd &	H,
		bool	update_kinematics = `true`
	)

Computes the joint space inertia matrix by using the Composite Rigid Body Algorithm.

This function computes the joint space inertia matrix from a given model and the generalized state vector: $ M(q) $

Parameters

model	rigid body model
Q	state vector of the model
H	a matrix where the result will be stored in
update_kinematics	whether the kinematics should be updated (safer, but at a higher computational cost!)

Note: This function only evaluates the entries of H that are non-zero. One Before calling this function one has to ensure that all other values have been set to zero, e.g. by calling H.setZero().

◆ ForwardDynamics()

RBDL_DLLAPI void RigidBodyDynamics::ForwardDynamics	(	Model &	model,
		const Math::VectorNd &	Q,
		const Math::VectorNd &	QDot,
		const Math::VectorNd &	Tau,
		Math::VectorNd &	QDDot,
		std::vector< Math::SpatialVector > *	f_ext = `NULL`
	)

Computes forward dynamics with the Articulated Body Algorithm.

This function computes the generalized accelerations from given generalized states, velocities and forces: $\ddot{q} = M(q)^{-1} ( -N(q, \dot{q}) + \tau)$ It does this by using the recursive Articulated Body Algorithm that runs in $O(n_{dof})$ with $n_{dof}$ being the number of joints.

Parameters

model	rigid body model
Q	state vector of the internal joints
QDot	velocity vector of the internal joints
Tau	actuations of the internal joints
QDDot	accelerations of the internal joints (output)
f_ext	External forces acting on the body in base coordinates (optional, defaults to NULL)

◆ ForwardDynamicsLagrangian()

RBDL_DLLAPI void RigidBodyDynamics::ForwardDynamicsLagrangian	(	Model &	model,
		const Math::VectorNd &	Q,
		const Math::VectorNd &	QDot,
		const Math::VectorNd &	Tau,
		Math::VectorNd &	QDDot,
		Math::LinearSolver	linear_solver = `Math::LinearSolverColPivHouseholderQR`,
		std::vector< Math::SpatialVector > *	f_ext = `NULL`,
		Math::MatrixNd *	H = `NULL`,
		Math::VectorNd *	C = `NULL`
	)

Computes forward dynamics by building and solving the full Lagrangian equation.

This method builds and solves the linear system

$H \ddot{q} = -C + \tau$

for $\ddot{q}$ where $H$ is the joint space inertia matrix computed with the CompositeRigidBodyAlgorithm(), $C$ the bias force (sometimes called "non-linear effects").

Parameters

model	rigid body model
Q	state vector of the internal joints
QDot	velocity vector of the internal joints
Tau	actuations of the internal joints
QDDot	accelerations of the internal joints (output)
linear_solver	specification which method should be used for solving the linear system
f_ext	External forces acting on the body in base coordinates (optional, defaults to NULL)
H	preallocated workspace area for the joint space inertia matrix of size dof_count x dof_count (optional, defaults to NULL and allocates temporary matrix)
C	preallocated workspace area for the right hand side vector of size dof_count x 1 (optional, defaults to NULL and allocates temporary vector)

◆ InverseDynamics()

RBDL_DLLAPI void RigidBodyDynamics::InverseDynamics	(	Model &	model,
		const Math::VectorNd &	Q,
		const Math::VectorNd &	QDot,
		const Math::VectorNd &	QDDot,
		Math::VectorNd &	Tau,
		std::vector< Math::SpatialVector > *	f_ext = `NULL`
	)

Computes inverse dynamics with the Newton-Euler Algorithm.

This function computes the generalized forces from given generalized states, velocities, and accelerations: $\tau = M(q) \ddot{q} + N(q, \dot{q}, f_\textit{ext})$

Parameters

model	rigid body model
Q	state vector of the internal joints
QDot	velocity vector of the internal joints
QDDot	accelerations of the internals joints
Tau	actuations of the internal joints (output)
f_ext	External forces acting on the body in base coordinates (optional, defaults to NULL)

◆ NonlinearEffects()

RBDL_DLLAPI void RigidBodyDynamics::NonlinearEffects	(	Model &	model,
		const Math::VectorNd &	Q,
		const Math::VectorNd &	QDot,
		Math::VectorNd &	Tau,
		std::vector< Math::SpatialVector > *	f_ext = `NULL`
	)

Computes the coriolis forces.

This function computes the generalized forces from given generalized states, velocities, and accelerations: $\tau = N(q, \dot{q}, f_\textit{ext})$

Parameters

model	rigid body model
Q	state vector of the internal joints
QDot	velocity vector of the internal joints
Tau	actuations of the internal joints (output)
f_ext	External forces acting on the body in base coordinates (optional, defaults to NULL)

Functions

Detailed Description

Function Documentation

◆ CalcMInvTimesTau()

◆ CompositeRigidBodyAlgorithm()

◆ ForwardDynamics()

◆ ForwardDynamicsLagrangian()

◆ InverseDynamics()

◆ NonlinearEffects()