A modified agile-eye mechanism for robotic manipulation of wristed
laparoscopic instruments
Abstract
Replacement of the exclusively designed instruments of the robotic
surgery systems with the commercial hand-held wristed instruments
provides advantages such as single-usability and cost reduction. A 4-DOF
robotic system, based on a modified non-symmetric 2-DOF agile-eye
mechanism, was developed to manipulate the hand-held wristed
instruments. The kinematics of the mechanism was analyzed, its
dimensions were optimized, and a functional prototype was tested
experimentally. The optimized mechanism had a great kinematic isotropy
(condition number <1.31) in the target workspace. Experimental
studies revealed a high tracking accuracy ($0.27 +- 0.01 deg rms for
the worse case) and a reasonably acceptable compliance (0.19 deg/N.m and
0.45 deg/N.m for the first and second kinematic chains respectively). By
satisfying the design requirement, the robotic manipulator provides an
attractive choice for robotic surgery systems. The performance of the
manipulator can be improved further by increasing the stiffness of the
second kinematic chain and performing kinematic calibration.