Experimental evaluation of task space regulators using unit quaternions on a direct-drive spherical wrist

This paper presents an experimental evaluation of four regulators in task space using unit quaternions to represent the end-effector orientation. We address the problem of regulation, that is, when the desired pose is constant. We present experimental results of the following control schemes: the resolved acceleration control, damped resolved acceleration control, hybrid damped resolved acceleration control, and transpose Jacobian-based control. All the controllers are tested on a three degrees-of-freedom spherical wrist.