I am trying to do inverse kinematics for a serial chain of arbitrarily many links.
In the following paper, I have found an example for how to calculate the Jacobian matrix.
Entry (i, j) = v[j] * (s[i] - p[j])
where:
v[j]is the unit vector of the axis of rotation for joint j
s[i]is the position (int world coords?) of joint i
p[j]is the position (in world coords?) of joint j
The paper says that this works if j is a rotational joint with a single degree of freedom. But my rotational joints have no constraints on their rotation. What formula do I then want? (Or am I possibly misunderstanding the term "degree of freedom"?)