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Updated: Jul 10, 2026

A Mechanical Construction to Enhance the Stability and Safety of Lifting and Thrusting Manipulation of Acupuncture
Published on: January 10, 2025
Variable-Curvature Bending Characteristic and Kinematic Model of Cannula Flexible Needle
He Zhang1, Yan-Jiang Zhao1,2, Yong-De Zhang1
1Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, Heilongjiang, China.
Background:
Compared with the conventional bevel-tip flexible needles, the cannula flexible needle has a superiority in terms of agility. To improve the insertion accuracy of the cannula flexible needle in the soft tissue, the variable-curvature bending characteristics were explored and a kinematic model was developed.
Methods:
This paper identified the parameters that influence the needle bending using a combination of the dimensional analysis theory and the equivalent stiffness method. Based on this, a kinematic model was established considering the deviation and rebound of the needle shaft. Verification experiments with the different stylet extension lengths for the flexible needle were conducted. Moreover, the single-arc and the double-arc insertion experiments were performed.
Results:
The results showed that all errors were within 2 mm, which met the accuracy requirements of general clinical surgery.
Conclusions:
The rationality and accuracy of the proposed variable-curvature bending characteristic model and the kinematic model are validated by experiments.
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