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Design and analysis of a stiffness adjustable structure using an endoskeleton

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Abstract

In this paper, we present a novel stiffness adjustable structure that changes its stiffness by pulling a tendon. It adopts an endoskeleton structure where rigid segments and compliant segments are alternately connected in series. The stiffness of this structure is controlled by compressing the compliant segments with an axial force. A tendon that runs through the endoskeleton and is fixed at the tip provides the axial compression force when pulled. We analyze the structure using the cylindrical isolation bearing model. The bending stiffness of the proposed structure was simulated and compared with experimental results. The structure can be stiffened approximately fifty-times the original stiffness. This stiffness adjustable structure can be used to increase the efficiency of a system that uses compliance, e.g., a robotic fish that uses a compliant fin for its propulsion system.

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Abbreviations

E :

Young’s Modulus

I :

second moment of inertia

R :

radius of cylinder

γ :

characteristic radius factor

t :

thickness of rigid segment

F :

load on end-tip of the structure

K :

pseudo torsional spring constant

c θ :

parametric angle coefficient

(EI)′:

effective bending stiffness of bonded cylindrical layer

θ i :

deflection angle of i th compliant segment from fixed-end

G :

Shear Modulus

S :

shape factor

l :

compressed length

D :

deflection

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Authors and Affiliations

  1. Biorobotics Laboratory, School of Mechanical & Aerospace Engineering / IAMD, Seoul National University, Seoul, Republic of Korea, 151-742

    Tae Myung Huh, Yong-Jai Park & Kyu-Jin Cho

Authors
  1. Tae Myung Huh
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  2. Yong-Jai Park
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  3. Kyu-Jin Cho
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Corresponding author

Correspondence to Kyu-Jin Cho.

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Huh, T.M., Park, YJ. & Cho, KJ. Design and analysis of a stiffness adjustable structure using an endoskeleton. Int. J. Precis. Eng. Manuf. 13, 1255–1258 (2012). https://doi.org/10.1007/s12541-012-0168-2

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  • DOI: https://doi.org/10.1007/s12541-012-0168-2

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