Review of Flexible Robot Stiffness Modulation Strategies

doi:10.3901/JME.260088

Abstract

Abstract: Flexible robots with multiple degrees of freedom can be driven to adapt to various shapes and complex environments with lower risks for their inherent flexibility. Robotics development has become one of the hot spots since its broad applications in many fields, such as biomedicine, pipeline maintenance, and rescue, are prospected. However, the low stiffness brought by flexibility makes it difficult to support and manipulate objects under high load conditions. Inspired by natural creatures, researchers introduced adjustable stiffness elements and materials into flexible robots to switch between rigid and flexible states alternately, which provides an effective method to solve the potential contradiction between compliance and high stiffness. This paper presents a systematic review of the latest advances in research on stiffness modulation for flexible robots, including the methods used for stiffness modulation and program configurations. The stiffness modulation principles are classified as intelligent material-based stiffness modulation, structure-based stiffness modulation, and interference-based stiffness modulation. At the same time, the combination of various stiffness modulation methods, especially the variable stiffness strategy combining interference structure and origami technology, is introduced. With the development of material science and mechanical structure technology, adjustable stiffness flexible robots with high load-carrying capacity, high flexibility, and lightweight will become an important research direction in future robotics.

Key words: flexible robot, tunable stiffness, large load, biomimetic

CLC Number:

TP24

PAN Xueting, YANG Fei, GENG Zhongtai, YUE Honghao, XU Jinsui, WANG Zheping. Review of Flexible Robot Stiffness Modulation Strategies[J]. Journal of Mechanical Engineering, 2026, 62(3): 311-339.

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