A parallel Remote Center of Motion mechanism for needle-based medical interventions

A novel parallel Remote Center of Motion (RCM) mechanism is proposed for a surgical robot designed to perform minimally invasive needle-based interventions for lung cancer diagnosis and treatment. The proposed robot provides four degrees of freedom (DOFs) to orient and move a surgical needle within a spherical coordinate system. The RCM is beneath the skin surface to minimize the invasiveness of the surgical procedure while providing the required workspace. This compact, patient-mounted robot benefits from a design capable of measuring the pure interaction forces between the needle and the tissue. In this paper, the mechanism design and its specifications are described. The kinematic analysis is presented and isotropy of the mechanism for targeting tumors is studied. Finally, the performance of the proposed robot is evaluated experimentally.