Kinematics of a Fully-Decoupled Remote Center-of-Motion Parallel Manipulator for Minimally Invasive Surgery

Abstract

A crucial design challenge in minimally invasive surgical (MIS) robots is the provision of a fully decoupled four degrees-of-freedom (4-DOF) remote center-of-motion (RCM) for surgical instruments. In this paper, we present a new parallel manipulator that can generate a 4-DOF RCM over its end-effector and these four DOFs are fully decoupled, i.e., each of them can be independently controlled by one corresponding actuated joint. First, we revisit the remote center-of-motion for MIS robots and introduce a projective displacement representation for coping with this special kinematics. Next, we present the proposed new parallel manipulator structure and study its geometry and motion decouplebility. Accordingly, we solve the inverse kinematics problem by taking the advantage of motion decouplebility. Then, via the screw system approach, we carry out the Jacobian analysis for the manipulator, by which the singular configurations are identified. Finally, we analyze the reachable and collision-free workspaces of the proposed manipulator and conclude the feasibility of this manipulator for the application in minimally invasive surgery.

Minimally-invasive-surgery parallel robot with non-identical limbs

“…A parallel manipulator, which 3UPRU-1S structure restricts the motion of the moving platform to spherical one, has been proposed for application in laparoscopic surgery [11]. A new 4-degree-of-freedom parallel manipulator providing RCM over the end-effector was presented in [12]. Interesting for this manipulator is the fact that the four degrees of freedom are fully decoupled.…”

Development of New End-Effector for Proof-of-Concept of Fully Robotic Multichannel Biopsy

“…In addition, a bulky robot system may be psychologically intimidating to patients [12]. End-effectors mounted on a downscaled frame or patient without an articulated arm [13]- [16] have also been developed. The frame-or bed-mounted types have relatively limited adjustability in response to changes in the needle insertion point or target lesion location, and patient-mounted types may lose stable positioning when patients move unintentionally, such as abrupt movements due to pain, coughing, or heavy breathing.…”

“…A 5-DOF manipulator has a virtual RCM [28]. Various mechanisms have also been proposed using different kinematic mechanisms such as XY or XYZ stages [29], [30], Gough-Stewart type parallel platforms or parallel linkage [14]- [16], [31], and downscaled articulated arms [32]- [36].…”

Kinematic analysis of a novel uncoupled and isotropic 2-degree-of-freedom parallel mechanism

“…,(17),(21), and (22), we can obtain ((l + q 23 )c 22a + es 224 ) = c 224 ð32Þ q 21 = 6 0:5p or q 224 = 6 0:5p are singular configurations.…”

“…4. When q 21 = 6 0:5p based on equations (17) and (21), there are three different combinations: (a) q 12 = 6 0:5p, q 11 6 ¼ 6 0:5p, q 224 = 0, J j j = 0. The rank of the J c reduces from 4 to 3, it is the constraint singularity.…”