Anatomy-Aware Dexterity-Driven Design Optimization of Surgical Continuum Robots

Tony Qin; Peter Connor; Khoa Dang; Carter Hatch; Caleb Rucker; Robert J. Webster; Ron Alterovitz

cs.ROSep 25, 2026

Anatomy-Aware Dexterity-Driven Design Optimization of Surgical Continuum Robots

Authors: Tony Qin, Peter Connor, Khoa Dang, Carter Hatch, Caleb Rucker, Robert J. Webster, Ron Alterovitz

Organizations: Department of Computer Science, University of North Carolina at Chapel Hill · Department of Mechanical Engineering, Vanderbilt University · Department of Mechanical, Aerospace, and Biomedical Engineering at The University of Tennessee, Knoxville

Abstract

Performing complex medical procedures with continuum robots requires careful selection of their geometric design parameters. The robot should have high dexterity in the specific anatomical environment of its procedure. This work presents a design optimization method that considers both dexterity and anatomy. We introduce the Reachable Volumetric Dexterous Solid Angle (RVDSA) metric as our objective, which measures the ability of a robot's end effector to reach the points in a goal volume from different directions via collision-free paths from a start configuration. We present a computationally efficient motion planner to compute this objective function for a given robotic design, and we use an asymptotically optimal simulated annealing optimizer to compute an optimized design. We applied our new method to optimize the design of a bimanual dexterous sheaths robot for performing procedures on cancerous polyps in colon anatomies, achieving a 78% higher RVDSA on average than optimizing for 3D voxel coverage alone.

Figures & tables

Panel of Figure 1 — Fig. 1 : We define the RVDSA metric to evaluate the quality of the geometric design of a surgical continuum robot and apply it to the dexterous sheaths robot for procedures in the colon. (a) Colon anatomy from a CT scan and computed centerline. (b) Constant curvature backbones reaching target voxels in the colon anatomy from the computed colonoscope location depicted as a black dot. (c) The discretization of the goal volume $\mathcal{G}$ into voxels. Each polyp voxel has a discretized unit sphere representing the directional component of the end effector. (d) Discretization of the unit sphere $\mathbb{S}^{2}$ into a subdivided icosahedron. Each triangle on the discretized unit sphere is marked green if it is reached at that voxel and direction. The RVDSA metric is computed from the percentage of triangles reached.

Fig. 2 : The five colon anatomies of our dataset with the location of each polyp circled in red.

Panel of Figure 3 — Fig. 3 : (a) Random sampling. (b) Inverse kinematics sampling that brings the end effector to a goal voxel. (c) Self-motion sampling that reaches a goal voxel from many different directions.

Fig. 4 : Rendering of the bimanual dexterous sheaths robot in the colon reaching a cancerous polyp from many different directions. The design variables $d_{1}$ to $d_{3}$ are set at time of fabrication of the sheath’s constituent tubes and remain fixed throughout a procedure. During a procedure, the robot is actuated through its degrees of freedom $q_{1}$ to $q_{6}$ . Note that the tubes can be retracted so the full length of $d_{1},d_{2},d_{3}$ may not be exposed.

Design Variable	Range
$d_{1}:$ Outer pair length	$[0,50]$ mm
$d_{2}:$ Outer pair straight section length	$[0,50]$ mm
$d_{3}:$ Inner pair length	$[0,50]$ mm

TABLE I : Design Variables

TABLE II : Degrees of Freedom

Fig. 5 : The RVDSA is plotted as a function of run time for our method, Jacobian-only sampling, random-only sampling, and a voxel-optimized method. Each condition is run four times, with the mean and variance being displayed. The best RVDSA achieved by our method is $2.65$ steradians, which is equivalent to a cone angle of $109.3$ degrees.

Panel of Figure 8 — Fig. 6 : We compute the RVDSA of the best designs found across all runs for three different conditions. We display the discretized sphere coverage percentage for each individual triangle averaged over all polyp voxels and the two end effectors, after normalizing directions to the scope start frames.

Explore similar work

Apr 22, 2026

Kinematic Optimization of Phalanx Length Ratios in Robotic Hands Using Potential Dexterity

In the design stage of robotic hands, it is not straightforward to quantitatively evaluate the effect of phalanx length ratios on dexterity without defining specific objects or manipulation tasks. Therefore, this study presents a framework for optimizing the phalanx length ratios of a five-finger robotic hand based on potential dexterity within a kinematic structure. The proposed method employs global manipulability, workspace volume, overlap workspace volume, and fingertip sensitivity as evaluation metrics, and identifies optimal design configurations using a weighted objective function under given constraints. The reachable workspace is discretized using a voxel-based representation, and joint motions are discretized at uniform intervals for evaluation. The optimization is performed over design sets for both the thumb and the other fingers, and design combinations that do not generate overlap workspace are excluded. The results show that each phalanx does not contribute equally to the overall dexterity, and the factors influencing each phalanx are identified. In addition, it is observed that the selection of weighting coefficients does not necessarily lead to the direct maximization of individual performance metrics, due to the non-uniform distribution of evaluation measures within the design space. The proposed framework provides a systematic approach to analyze the trade-offs among reachability, dexterity, and controllability, and can serve as a practical guideline for the kinematic design of multi-fingered robotic hands.

HyoJae Kang, Joonho Lee, Jeongdo Ahn +1

Advanced Robotics Research Center, Korea Institute of Machinery & Materials (KIMM)

Robotic Hand Design Mechanism Design Dexterous Manipulation Robotics

Ask PDF

Apr 17, 2026

Contact-Aware Planning and Control of Continuum Robots in Highly Constrained Environments

Continuum robots are well suited for navigating confined and fragile environments, such as vascular or endoluminal anatomy, where contact with surrounding structures is often unavoidable. While controlled contact can assist motion, unfavorable contact can degrade controllability, induce kinematic singularities, or introduce safety risks. We present a contact-aware planning approach that evaluates contact quality, penalizing hazardous interactions, while permitting benign contact. The planner produces kinematically feasible trajectories and contact-aware Jacobians which can be used for closed-loop control in hardware experiments. We validate the approach by testing the integrated system (planning, control, and mechanical design) on anatomical models from patient scans. The planner generates effective plans for three common anatomical environments, and, in all hardware trials, the continuum robot was able to reach the target while avoiding dangerous tip contact (100% success). Mean tracking errors were 1.9 +/- 0.5 mm, 1.2 +/- 0.1 mm, and 1.7 +/- 0.2 mm across the three different environments. Ablation studies showed that penalizing end-of-continuum-segment (ECS) contact improved manipulability and prevented hardware failures. Overall, this work enables reliable, contact-aware navigation in highly constrained environments.

Aedan Mangan, Kehan Long, Ki Myung Brian Lee +3

Department of Mechanical and Aerospace Engineering, University of California San Diego, San Diego, CA 92093, USA · SceniX Inc, New York, NY 10011, USA · Department of Electrical and Computer Engineering, University of California San Diego, San Diego, CA 92093, USA +1

Constrained Motion Planning Continuum Robot Control Motion Planning Robot Motion Planning Surgical Robotics

Ask PDF

Aug 13, 2026

Capstan-driven Continuum Surgical Robot: Design, Modeling, and Perception

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

Continuum Robot Control Robot State Estimation Surgical Robotics

Ask PDF