Design and Modeling of a Single-Port Three-Arm Robotic Tool for Minimally Invasive Neurosurgery
Authors: Nazia H. Dana, Harith S. Gallage, Ismail A. Auta, Dhanvi Yuvaraj, Ronghuai Qi
Organizations: Robotics and Healthcare Systems (RoboHS) Laboratory, Department of Mechanical Engineering, University of Nevada, Las Vegas (UNLV), Las Vegas, NV, USA
Surgical robots require highly dexterous and compact robotic systems capable of operating effectively within confined anatomical spaces. However, due to limited access provided by a single incision, the miniaturization and maneuverability of these robots still need to be improved. In this paper, we propose the design and modeling of a single-port three-arm robotic tool containing one major cannula (7.14 mm outer diameter (OD)) and three steerable minor cannulas (1.93 mm OD). By integrating the proposed 12 degrees-of-freedom (DoFs) steerable robotic tool with a 7-DoF robotic arm, this robotic system can potentially achieve multi-arm manipulation capability. We present the design of the steerable robotic tool consisting of tendon-driven joints controlled by a compact actuation system, derive the kinematic model, and validate both the static and kinematic models through experiments. The performance is evaluated with the root mean square error (RMSE) and mean absolute error (MAE) computed between the experimental data and the kinematic model.
Figures & tables
Fig. 1: Single-port three -arm robotic tool for minimally invasive neurosurgery. (a) E ntire system and (b) close-up view of the minor cannulas.
Fig. 2: Schematic of the compact actuation system (CAS), (a) an exploded view of CAS with three steerable cannulas, (b) top view of the CAS, (c) redesigned spool, and (d) an exploded view of minor cannula actuator.
Fig. 3: Schematic of the robotically steerable minor cannula comprising of a proximal and a distal joint.
Fig. 4: Schematic of the minor cannulas with coordinate frames attached to the joints. (a) Unactuated state and (b) actuated state.
Fig. 5: 3D workspace of the three minor cannulas showing the overlap region.
Fig. 6: Experimental setup.
Fig. 7: Actuation of bending joints, (a) proximal, (b) distal , and (c) both proximal and distal.
Fig. 8: Experimental validation of joint static models of (a) proximal joint, (b) distal joint, (c) rotational joint , and (d) prismatic joint.
Fig. 9: Kinematic model validation of the (a)-(c) proximal, (g)-(i) distal, (j)-(l) rotational joints at 5∘ , 15∘ , and 25∘ , respectively, and (d)-(f) prismatic joint at 5 mm, 15 mm , and 25 mm insertion.
Fig. 10: Comparison of experimental and kinematic modeled tip trajectories for simultaneous joint actuation.
Fig. 11: Combined actuation of the joints: (a) initial position, (b) 10 mm prismatic translation, (c) 8 ∘ proximal bending, (d) 50 ∘ distal bending , and (e) 90 ∘ rotation.
Experiment
RMSE (mm)
MAE (mm)
Proximal
1.43
0.99
Distal
1.09
0.99
Rotational
0.22
0.21
Prismatic
0.92
0.82
Combined X
1.15
0.84
Combined Y
3.15
2.19
TABLE I: Performance Evaluation of Kinematics Models
Long, slender instruments are essential for minimally invasive surgery (MIS), but achieving precise distal manipulation becomes increasingly difficult when actuation extends along the entire instrument. Here, we present an electrothermally actuated fiber-based robot designed for MIS procedures, in which Joule heating is concentrated in the distal active segment. The fiber is fabricated using a thermal drawing process and uses embedded metallic wires for thermal actuation. This robotic fiber, 1.9 mm in diameter and 1.2 m in length, can precisely manipulate surgical laser fibers with positional precision below 100 μm. The compact size of the fiber robot allows it to pass through the working channel of a flexible endoscope, while keeping both devices mechanically uncoupled to allow independent motion. A phantom demonstration combining the robotic fiber with a da Vinci instrument conceptually demonstrated its compatibility with existing endoscopic systems for clinical applications. Our robotic fiber enables precise distal motion and holds the potential to improve clinical outcomes by enhancing precision in MIS procedures.
Jinshi Zhao, Libaihe Tian, Alex Ranne +9
Department of Metabolism, Digestion and Reproduction, Imperial College London, SW7 2AZ, UK · Hamlyn Centre for Robotic Surgery, Imperial College London, SW7 2AZ, UK · Department of Bioengineering, Imperial College London, SW7 2AZ, UK +1
Shape and force sensing have long been critical bottlenecks in the development of compact capstan-driven continuum surgical robots, primarily due to the difficulty of obtaining cable tension information within the confined capstan assembly. To overcome these challenges, this paper presents an integrated design-modeling-sensing approach based on the concept of actuation-perception co-design. A compliant element is introduced into the motor mounting bracket of the drive system, enabling micro-deformation under the cable reaction force and thereby allowing real-time cable tension measurement without occupying the compact capstan space. To address the modeling complexity arising from unconventional joint configurations introduced by the spatial cable routing strategy, a parallel computation framework based on a multibody short-thick-beam model is proposed, which captures shear effects in short beam segments and synergistic multi-cable interactions while achieving real-time performance. Building on this framework, stable shape and force sensing is achieved by incorporating a proximal multi-axis force/torque sensor as an additional measurement anchor. Following this design-modeling-sensing framework, capstan-driven continuum surgical robots with single- and dual-segment configurations are developed. Experimental results validate the proposed framework in both single- and dual-segment continuum robots, demonstrating real-time tip pose estimation together with contact force and location perception. By enabling cable tension feedback without compromising the compact capstan architecture, the proposed framework makes integrated perception feasible for capstan-driven continuum surgical robots.
Gang Zhang, Yufu Qiu, Junyan Yan +3
Department of Mechanical and Automation Engineering and T Stone Robotics Institute, The Chinese University of Hong Kong, Hong Kong · School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070, China · state Key Laboratory of Intelligent Manufacturing Equipment and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China +1
We present a kinematic and transmission-aware design framework for a serial spherical mechanism with an additional translational degree of freedom for microsurgery. The first contribution is an analytical workspace formulation that provides geometric insight into reachable motion and enables rapid selection of rotation axis orientations without numerical optimization. The second contribution is a dynamics-informed methodology for mechanisms driven by self-locking transmissions, supporting evaluation of torque requirements for a prescribed workspace geometry. The framework is accompanied by an open-source software package for friction identification and inverse dynamics analysis. Experiments on a purpose-built robotic tool for vitreoretinal surgery validate the predictive capability of the models and demonstrate their practical utility for engineering design.
Anestis Mablekos-Alexiou, Lyndon da Cruz, Christos Bergeles
Moorfields Eye Hospital NHS Foundation Trust, London, UK · King’s College London