Jacobian derivative

[jalfonsossm]

Hi,

Sorry for my poor english, I hope you can understand this post

Given the internal joint angles (joint states) and velocities. I want to compute the acceleration on an end effector of a floating base robot (the acceleration of a human foot in its ground contacts points) using the formula:

J_dot * state_dot + J * state_dot_dot

I need to compute both jacobian and its derivative. But I have problems to compute J_dot cortrectly. Someone colud help me? Any snapshot of code will be very helpfull.

Thanks

juanal

[Dirk Gregorius]

What joint type do you want: spherical, revolute, ...?

[jalfonsossm]

we need 6 DOF for floating base (a prismatic and a rotational joint) but for a internal human joints, I only use rotational joints (for my tests I am using only hinge joints for now).

We can calculate Jacobian, and this works well, but I don´t be able to find an examples or code for compute its derivative geometrically.

[Dirk Gregorius]

I would build the time derivative again and find the result by inspection.