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Design and modelling of a continuum robot with soft stiffness-adjustable elements for confined environments
  • NAN MA
University of Nottingham

Corresponding Author:[email protected]

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Abstract—Continuum robots are increasingly used in a wide range of industrial applications due to their slender body and high redundancy, making them ideal for intervention in confined environments. However, most of the existing continuum robots operate with their backbone in a cantilever configuration, resulting in a limited accuracy at the tip because of their low stiffness. This paper proposes a new method to improve the stiffness of continuum robots, characterized by: (1) a modular section with adjustable stiffness (MSAS), able to inflate its diameter by ten times to provide physical support for a 6-DoF operating section; (2) a novel stiffness model developed to study the behaviour of the hybrid stiffening continuum arm; (3) a manual insertion method for an easy delivery with a limited number of actuators. The proposed stiffness model, which combines the stiffness characteristics of the MSAS and a 6-DoF continuum arm, predicts the performance of the novel hybrid continuum robot with an average deviation of 9.2% under external loads. A prototype has been demonstrated on a case study in a Trent 900 aeroengine, where the MSAS, with a natural diameter of 12.6 mm, is delivered through an inspection hole of 13 mm and then inflated (120 mm) to successfully lock the robot within the combustor (width: 200 mm; height: 110 mm). The physical support enables accurate operation with the 6-DoF continuum arm at the tip, indicating that the proposed design can improve the performance of conventional continuum robots.