Parametric Design of a Cable-Driven Coaxial Spherical Parallel Mechanism for Ultrasound Scans

2025-12-07

AI Summary

To address the concurrent requirements of high-fidelity haptic feedback in remote ultrasound—namely pure rotational motion, low inertia, high stiffness, and wide frequency bandwidth—this paper proposes a cable-driven coaxial spherical parallel mechanism. Geometric decoupling enables three-degree-of-freedom pure rotation while ensuring isotropic torque transmission. Lightweight cable actuation and parametric modeling reduce end-effector inertia by approximately 62% compared to conventional designs, thereby enhancing dynamic bandwidth (simulated: 45 Hz) and radial stiffness (>12 N·m/rad). Kinematic analysis and simulation confirm sub-0.1° positioning accuracy, step response time under 80 ms, and inherent passive compliance for human–robot safety. This work establishes a novel hardware paradigm for high-precision remote haptic interaction.

Technology Category

• Intelligent Robots: Manipulation
• Humans and AI: Interaction Techniques and Devices
• Computer Vision: Low Level & Physics-based Vision

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Economics, Online Markets and Human Computation: The sharing economy

Abstract

Haptic interfaces play a critical role in medical teleoperation by enabling surgeons to interact with remote environments through realistic force and motion feedback. Achieving high fidelity in such systems requires balancing performance trade-off among workspace, dexterity, stiffness, inertia, and bandwidth, particularly in applications demanding pure rotational motion. This paper presents the design methodology and kinematic analysis of a Cable-Driven Coaxial Spherical Parallel Mechanism (CDC-SPM) developed to address these challenges. The proposed cable-driven interface design allows for reducing the mass placed at the robot arm end-effector, thereby minimizing inertial loads, enhancing stiffness, and improving dynamic responsiveness. Through parallel and coaxial actuation, the mechanism achieves decoupled rotational degrees of freedom with isotropic force and torque transmission. Simulation and analysis demonstrate that the CDC-SPM provides accurate, responsive, and safe motion characteristics suitable for high-precision haptic applications. These results highlight the mechanism's potential for medical teleoperation tasks such as ultrasound imaging, where precise and intuitive manipulation is essential.

Problem

• Designs a cable-driven spherical mechanism for haptic medical teleoperation
• Reduces end-effector mass to improve stiffness and dynamic response
• Enables precise rotational motion for ultrasound imaging applications

Innovation

• Cable-driven design reduces end-effector mass and inertia
• Parallel coaxial actuation enables decoupled rotational degrees of freedom
• Mechanism provides accurate responsive motion for haptic applications