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Tailoring the in-plane and out-of-plane stiffness of soft fingers by endoskeleton topology optimization for stable gras**

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Abstract

The intrinsic compliance of soft materials endows soft robots with great advantages to achieve large deformation and adaptive interactions in gras** tasks. However, current soft grippers usually focus on the in-plane large deformation and load capacity but ignore the effect of out-of-plane external loads, which may lead to instability in practical scenarios. This problem calls for stiffness design along multiple directions to withstand not only in-plane interacting forces with objects, but also unexpected out-of-plane loads. In this paper, we design a new type of soft finger by embedding an endoskeleton inside the widely-used Pneu-Nets actuator, and the endoskeleton layout is optimized to achieve a remarkable bending deflection and limited lateral deflection under combined external in-plane and out-of-plane loads. Based on the multi-objective topology optimization approach, the key structural features of the optimized endoskeleton are extracted and parameterized. The multi-material soft fingers are fabricated by the silicone compound mold method. Static and dynamic experiment results validate that the soft gripper with endoskeleton embedded exhibits remarkably improved out-of-plane stiffness, without sacrificing the in-plane bending flexibility, and leads to more stable gras**.

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Authors and Affiliations

  1. State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China

    DeChen Li, ShiTong Chen, ZeNan Song, JiaLong Liang, **angYang Zhu & FeiFei Chen

  2. Meta Robotics Institute, Shanghai Jiao Tong University, Shanghai, 200240, China

    **angYang Zhu & FeiFei Chen

Authors
  1. DeChen Li
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  2. ShiTong Chen
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  3. ZeNan Song
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  4. JiaLong Liang
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  5. **angYang Zhu
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  6. FeiFei Chen
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Correspondence to FeiFei Chen.

Additional information

This work was supported by the National Natural Science Foundation of China (Grant Nos. 52275026 and 91948302) and the State Key Laboratory of Structural Analysis for Industrial Equipment (Grant No. GZ21117).

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Li, D., Chen, S., Song, Z. et al. Tailoring the in-plane and out-of-plane stiffness of soft fingers by endoskeleton topology optimization for stable gras**. Sci. China Technol. Sci. 66, 3080–3089 (2023). https://doi.org/10.1007/s11431-022-2346-6

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  • DOI: https://doi.org/10.1007/s11431-022-2346-6

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