Multi-slider linkage mechanism for endoscopic forceps manipulator

This paper proposes a new endoscopic hand-held forceps manipulator for endoscopic surgery using two bending mechanisms by multi-slider linkage mechanisms to achieve high mechanical performance and applicability. A bending mechanism consisted of three outer frames, two rotating joints and two sliding linkages for drive and restraint. Two pin-joints could rotate ±45 degrees respectively, enabling rotation of ±90 degrees. The rotation of the joint was available by pulling/pushing the adjacent element by sliding linkage in order. We connected two bending mechanisms, one was for the horizontal plane bending and the other was for the vertical plane bending, enabling 2-DOFs independent motions between -90 degrees and +90 degrees. The 2-DOFs bending mechanism and 1-DOF forceps mechanism were driven by three brushless DC-servomotors. A personal computer-based control unit determined displacement of sliding two linkages and of pulling one wire by the target angle of each DOF mechanism. We examined the actual angle of 2-DOFs bending mechanism, obtaining repeatability of ±0.87 degrees in the horizontal plane bending and ±0.91 degrees in the vertical plane bending. In vivo experiment, this manipulator performed endoscopic surgical tasks under pneumoperitoneum. In conclusion, we were sure of a usefulness of multi-slider linkage mechanism for the new handheld forceps manipulator for clinical application, which showed high repeatability of less 1.0 mm and large workspace with sufficient holding power of 0.55 kgf.