Leg Class Reference

Quadruped Leg. More...

#include <Leg.hpp>

Public Types
enum	state_t {   IDLE , HOMING , RUNNING , LIFT ,   PLACE }
	Leg State.

Public Member Functions
	Leg (Eigen::Vector< double, njoints+1 > &l, Eigen::Matrix< double, 6, njoints > &Slist, Eigen::Isometry3d &M, std::array< Eigen::Isometry3d, njoints+1 > &Mlist, std::array< Eigen::Matrix6d, njoints > &Glist, Eigen::Matrix< double, njoints, 2 > &thetaRange, Eigen::Vector< double, njoints > &thetadMax, Eigen::Vector< double, njoints > &thetaddMax, Eigen::Vector< double, njoints > &tauMax)
	Leg Constructor.
bool	fk (const Eigen::Vector3d &thetalist, Eigen::Vector3d &pf)
	Forward Kinematics.
bool	ik (const Eigen::Vector3d &pf, Eigen::Vector3d &thetalist, Eigen::Matrix3d *Jinv=nullptr)
	Inverse Kinematics.
bool	ivk (const Eigen::Vector3d &vf, const Eigen::Matrix3d &Jinv, Eigen::Vector3d &thetadlist)
	Inverse Velocity Kinematics.
bool	id (Eigen::Vector< double, njoints > &taulist)
	Inverse Dynamics.
void	liftTo (const Eigen::Isometry3d &T)
bool	jointTrajectory (const Eigen::Isometry3d &Tstart, const Eigen::Isometry3d &Tgoal, const double t0, const double t, Eigen::Isometry3d &Tcurrent)
	Joint Trajectory.
void	run ()
	Run foot operations.

Public Attributes
enum Leg::state_t	state = IDLE
enum Leg::state_t	statep = IDLE
Eigen::Vector3d	pf
	Foot position [m].
Eigen::Vector3d	vf
	Foot velocity [m/s].
Eigen::Vector3d	dvf
	Foot acceleration [m/s^2].
Eigen::Vector3d	ff
	Foot force [N].
Eigen::Vector3d	g
	Gravity [m/s^2].
Eigen::Vector< double, njoints >	thetalist
Eigen::Vector< double, njoints >	thetadlist
Eigen::Vector< double, njoints >	thetaddlist
Eigen::Vector< double, njoints >	taulist

Private Attributes
const Eigen::Vector< double, njoints+1 >	l
const Eigen::Matrix< double, 6, njoints >	Slist
const Eigen::Isometry3d	M
const std::array< Eigen::Isometry3d, njoints+1 >	Mlist
const std::array< Eigen::Matrix6d, njoints >	Glist
const Eigen::Matrix< double, njoints, 2 >	thetaRange
const Eigen::Vector< double, njoints >	thetadMax
const Eigen::Vector< double, njoints >	thetaddMax
const Eigen::Vector< double, njoints >	tauMax
const Eigen::Vector< double, njoints >	thetadir
Eigen::Matrix< double, njoints, 3 >	Jinv
Eigen::Isometry3d	Mi
Eigen::Matrix< double, 6, njoints >	Ai
Eigen::Matrix< double, 6, njoints+1 >	Vi
Eigen::Matrix< double, 6, njoints+1 >	dVi
std::array< Eigen::Matrix6d, njoints+1 >	AdTi
Eigen::Vector6d	Fi

Detailed Description

Quadruped Leg.

The leg class contains gemotry and mass properties for one leg, the leg state, and functions to operate on the leg state.

Constructor & Destructor Documentation

Leg()

Leg::Leg ( Eigen::Vector< double, njoints+1 > & l, Eigen::Matrix< double, 6, njoints > & Slist, Eigen::Isometry3d & M, std::array< Eigen::Isometry3d, njoints+1 > & Mlist, std::array< Eigen::Matrix6d, njoints > & Glist, Eigen::Matrix< double, njoints, 2 > & thetaRange, Eigen::Vector< double, njoints > & thetadMax, Eigen::Vector< double, njoints > & thetaddMax, Eigen::Vector< double, njoints > & tauMax )

inline

Leg Constructor.

Parameters

[in]	l	4-vector of leg lengths
[in]	Slist	6x3 list of joint screw axes
[in]	M	Transform of the leg at zero joint angles
[in]	Mlist	Array of 4 transforms between joints at zero joint angles, beginning from the base (Identity)
[in]	Glist	Array of 3 6x6 spatial inertia matrices for the leg links
[in]	thetaRange	3x2 matrix of joint angle limits [low, high]
[in]	thetadMax	3-vector of joint velocity limits
[in]	thetaddMax	3-vector of joint acceleration limits
[in]	tauMax	3-vector of joint torque limits

Member Function Documentation

fk()

bool Leg::fk	(	const Eigen::Vector3d &	thetalist,
		Eigen::Vector3d &	pf )

Forward Kinematics.

Compute foot position from joint angles

Parameters

[in]	thetalist	3-vector of joint angles
[out]	pf	3-vector resultant foot position

id()

bool Leg::id

(

Eigen::Vector< double, njoints > &

taulist

)

Inverse Dynamics.

Compute joint torque from foot state

Parameters

[out]

taulist

joint torques

ik()

bool Leg::ik	(	const Eigen::Vector3d &	pf,
		Eigen::Vector3d &	thetalist,
		Eigen::Matrix3d *	Jinv = nullptr )

Inverse Kinematics.

Compute joint angles (and Jacobian inverse) at a given foot position

Parameters

[in]	pf	3-vector foot position
[out]	thetalist	3-vector resultant joint angles
[out]	Jinv	3x3 resultant Jacobian inverse (dtheta/dp)

ivk()

bool Leg::ivk	(	const Eigen::Vector3d &	vf,
		const Eigen::Matrix3d &	Jinv,
		Eigen::Vector3d &	thetadlist )

Inverse Velocity Kinematics.

Compute joint velocities for a given foot position velocity

Parameters

[in]	vf	3-vector foot velocity
[in]	Jinv	3x3 Jacobian inverse at the current position (thetad/dp)
[out]	thetadlist	3-vector resultant joint angles

jointTrajectory()

bool Leg::jointTrajectory	(	const Eigen::Isometry3d &	Tstart,
		const Eigen::Isometry3d &	Tgoal,
		const double	t0,
		const double	t,
		Eigen::Isometry3d &	Tcurrent )

Joint Trajectory.

Compute joint angles at a specified time on a joint trajectory

Parameters

[in]	Tstart	SE(3) beginning foot pose
[in]	Tgoal	SE(3) ending foot pose
[in]	t0	Time at beginning of trajectory
[in]	t	Current time
[out]	T	SE(3) current foot pose

Member Data Documentation

thetadir

const Eigen::Vector<double, njoints> Leg::thetadir

private

Initial value:

{Slist(0, 0) * Slist(1, 1),
                                                Slist(1, 1), Slist(1, 1)}

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The documentation for this class was generated from the following files:

• include/Leg.hpp
• src/Leg.cpp