# Task Space Control Parameters for 6-Dof Manipulator

I'm developing a Task Space controller based on speed for a Universal Robot 5. I've already calculated the Jacobian, position and rotation error for the classic control method:

$\dot{q} = J^{-1}K(p_d - p)$

The method works fine in simulations (ODE Engine, Ros URDF), however, on a real UR5, I can't simply use the K parameters from simulations. From my experience, because the last three motors of the UR5 differ from the first three, the last three joint motors are much more sensible in relation to the value of the parameters in the K matrix. I managed to get to a 5 mm error in position with low parameters for the last 3 joints, but it's still unstable for long experiments (3+ minutes).

My question is, is there a method in the literature for optimal tuning of Task Space Controllers? How is it normally done? I couldn't find specific papers about it.

• Is your $J^{-1}$ full rank? – koverman47 Apr 26 at 21:48