MATLAB File Help: HebiKinematics/getJacobian
HebiKinematics/getJacobian
```  getJacobian calculates the matrix that relates input joint
velocities to body velocities.

This method calculates the partial derivatives of the
kinematics equation, which relates the joint velocities to
the linear and angular velocities of each body in the
kinematic chain.

More background on Jacobians and kinematics can be found at:
http://docs.hebi.us/core_concepts.html#kinematics

The Jacobian is returned as a [6 x numDoF x numBodies] set
of matrices.  Rows 1:3 of the Jacobian correspond to linear
velocities [m/s] along the X-Y-Z axes in the world frame,
while rows 4:6 correspond to rotational velocities [rad/s]
about the X-Y-Z axes in the world frame.

'FrameType' Argument
'OutputFrame'      calculates the transforms to the output
of each body (also: 'out', 'output')

'CoMFrame'         calculates the transforms to the center
of mass of each body (also: 'com')

'EndEffectorFrame' calculates the transform to only the
output frame of the last body, e.g.,
a gripper (also: 'endeffector')

'Position' Argument
A [1 x numDoF] vector that specifies the position
of each degree of freedom. Rotational positions are
specified in [rad].  Translational positions are
specified in [m].

'FixedFrame' Argument
A number that specifies which rigid body of the Jacobian is
assumed to be fixed, and returns the Jacobian in this frame.
This parameter is optional, and the default if not specified is
the world frame, which would be the same as ['fixedframe', 0].

This parameter uses negative indexing to specify the end-effector
as -1 regardless of the number of links in kinenamitic chain.
Note that if you want the frame at the usual origin of the chain
to be returned in the Jacobian, you will need to add a body there
in the HRDF file or kinematic definition code, as the base frame
of the chain is normally omitted from forward kinematics and
Jacobian calculations.

Examples
% End-Effector Jacobian using group feedback
fbk = group.getNextFeedback();
J = kin.getJacobian('endEffector', fbk.position);

% Jacobian assuming the end-effector is fixed, using group
% feedback. For example, if the kinematic chain were a
% leg and the end-effector (the foot) is fixed to the ground.
fbk = group.getNextFeedback();
J = kin.getJacobian('output', fbk.position, 'fixedframe', -1);```
See also
Method Details
 Access public Sealed false Static false