Tendon-Actuated Robots with a Tapered, Flexible Polymer Backbone: Design, Fabrication, and Modeling
🤖 AI Summary
This work proposes a tendon-driven continuum robot featuring a tapered flexible backbone fabricated from thermoplastic polyurethane (TPU), addressing limitations of conventional designs—such as high cost, poor customizability, and the difficulty of simultaneously achieving high curvature and distal compliance—in flexible manipulation tasks. An integrated electronic base enables precise tendon tension control and sensing. For the first time, the spatially varying tapered cross-section is explicitly incorporated into a forward dynamic-static model based on Cosserat rod theory to capture the influence of geometric tapering on stiffness distribution. Leveraging fused deposition modeling 3D printing and parametric CAD design, the system achieves low-cost, rapid assembly, and high customizability. Experimental calibration demonstrates centimeter-level shape prediction accuracy, and successful teleoperated endoscopic grasper tasks validate the robot’s efficacy in complex flexible manipulation scenarios.
Application Category
📝 Abstract
This paper presents the design, modeling, and fabrication of 3D-printed, tendon-actuated continuum robots featuring a flexible, tapered backbone constructed from thermoplastic polyurethane (TPU). Our scalable design incorporates an integrated electronics base housing that enables direct tendon tension control and sensing via actuators and compression load cells. Unlike many continuum robots that are single-purpose and costly, the proposed design prioritizes customizability, rapid assembly, and low cost while enabling high curvature and enhanced distal compliance through geometric tapering, thereby supporting a broad range of compliant robotic inspection and manipulation tasks. We develop a generalized forward kinetostatic model of the tapered backbone based on Cosserat rod theory using a Newtonian approach, extending existing tendon-actuated Cosserat rod formulations to explicitly account for spatially varying backbone cross-sectional geometry. The model captures the graded stiffness profile induced by the tapering and enables systematic exploration of the configuration space as a function of the geometric design parameters. Specifically, we analyze how the backbone taper angle influences the robot's configuration space and manipulability. The model is validated against motion capture data, achieving centimeter-level shape prediction accuracy after calibrating Young's modulus via a line search that minimizes modeling error. We further demonstrate teleoperated grasping using an endoscopic gripper routed along the continuum robot, mounted on a 6-DoF robotic arm. Parameterized iLogic/CAD scripts are provided for rapid geometry generation and scaling. The presented framework establishes a simple, rapid, and reproducible pathway from parametric design to controlled tendon actuation for tapered, tendon-driven continuum robots manufactured using fused deposition modeling 3D printers.
Problem
Research questions and friction points this paper is trying to address.
continuum robots
tendon actuation
flexible backbone
customizability
low-cost design
Innovation
Methods, ideas, or system contributions that make the work stand out.
tendon-actuated continuum robot
tapered flexible backbone
Cosserat rod modeling
3D-printed soft robotics
parametric design
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