Key technologies of bionic inchworm robots: a survey

Abstract

The bionic inchworm robot is known for its flexible and adaptable locomotion and has attracted growing interest in agriculture, forestry, and infrastructure inspection. This paper reviews global research on such robots, focusing on actuation mechanisms, attachment strategies, kinematic modeling, control methods and locomotion performance. By systematically comparing existing studies, it summarizes key technologies, identifies current challenges and outlines future research directions. The goal is to provide a clear perspective that supports further advances in inchworm-inspired robotic systems.

Keywords

Bionic inchworm robot / soft robot / attachment method / drive method / performance comparison

References

[1] Ueno S.,Takemura K.,Yokota S.,Edamura K.. Micro inchworm robot using electro-conjugate fluid Sens. Actuators A Phys. 2014 216 36 42

[2] Zhang Y.,Yang D.,Yan P.,Zhou P.,Zou J.,Gu G.. Inchworm inspired multimodal soft robots with crawling, climbing, and transitioning locomotion IEEE Trans. Robot. 2022 38 1806 19

[3] Ding J.,Su H.,Nong W.,Huang C.. An inchworm-inspired soft robot with combined functions of omni-directional steering and obstacle surmounting Ind. Robot. 2022 50 456 66

[4] Jiang Z.,Zhang K.. Force analysis of a soft-rigid hybrid pneumatic actuator and its application in a bipedal inchworm robot Robotica 2024 42 1436 52

[5] Chang A. H.,Freeman C.,Mahendran A. N.,Vikas V.,Vela P. A.. Shape-centric modeling for soft robot inchworm locomotion. In 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Prague, Czech Republic, September 27 - October 1, 2021; IEEE, 2021, pp 645-52

[6] Xie R.,Su M.,Zhang Y.,Li M.,Zhu H.,Guan Y.. PISRob: A pneumatic soft robot for locomoting like an inchworm. In 2018 IEEE International Conference on Robotics and Automation (ICRA), Brisbane, QLD, May 21-25, 2018; IEEE, 2018, pp 3448-53

[7] Gamus B.,Salem L.,Gat A. D.,Or Y.. Understanding inchworm crawling for soft-robotics IEEE Robot. Autom. Lett. 2020 5 1397 404

[8] Zheng Z.,Kumar P.,Chen Y..et al. Model-based control of planar piezoelectric inchworm soft robot for crawling in constrained environments. In 2022 IEEE 5th International Conference on Soft Robotics (RoboSoft), Edinburgh, United Kingdom, April 4-8, 2022; IEEE, 2022, pp 693-8

[9] Koh J.,Cho K.. Omega-shaped inchworm-inspired crawling robot with large-index-and-pitch (LIP) SMA spring actuators IEEE/ASME Trans. Mechatron. 2013 18 419 29

[10] Jing Z.,Li Q.,Su W.,Chen Y.. Dielectric elastomer-driven bionic inchworm soft robot realizes forward and backward movement and jump Actuators 2022 11 227

[11] Yang Y.,Li D.,Shen Y.. Inchworm-inspired soft robot with light-actuated locomotion IEEE Robot. Autom. Lett. 2019 4 1647 52

[12] Jung W.,Lee S.,Hwang Y.. Wireless inchworm-like compact soft robot by induction heating of magnetic composite Micromachines (Basel). 2023 14 162 PMC9865691

[13] Duduta M.,Clarke D. R.,Wood R. J.. A high speed soft robot based on dielectric elastomer actuators. In 2017 IEEE International Conference on Robotics and Automation (ICRA), Singapore, Singapore, May 29 - June 3, 2017; IEEE, 2017, pp 4346-51

[14] Duggan T.,Horowitz L.,Ulug A.,Baker E.,Petersen K.. Inchworm-Inspired Locomotion in Untethered Soft Robots. In 2019 2nd IEEE International Conference on Soft Robotics (RoboSoft), Seoul, Korea (South), April 14-18, 2019; IEEE, 2019, pp 200-5

[15] Das R.,Babu S. P. M.,Visentin F.,Palagi S.,Mazzolai B.. An earthworm-like modular soft robot for locomotion in multi-terrain environments Sci. Rep. 2023 13 1571 PMC9884293

[16] Sun J.,Bauman L.,Yu L.,Zhao B.. Gecko-and-inchworm-inspired untethered soft robot for climbing on walls and ceilings Cell Rep. Phys. Sci. 2023 4 101241

[17] Shen Y.,Isono R.,Kodama S..et al. Design of a pneumatically driven inchworm-like gas pipe inspection robot with autonomous control. In 2023 IEEE International Conference on Soft Robotics (RoboSoft), Singapore, Singapore, April 3-7, 2023; IEEE, 2023, pp 1-6

[18] Liu X.,Song M.,Fang Y.,Zhao Y.,Cao C.. Worm-inspired soft robots enable adaptable pipeline and tunnel inspection Adv. Intell. Syst. 2021 4 2100128

[19] Hu Z.,Li Y.,Lv J. A.. Phototunable self-oscillating system driven by a self-winding fiber actuator Nat. Commun. 2021 12 3211 PMC8163889

[20] Jiang J.,Yu Y.,Lin C.,Sun J.,Ma X.,Wang H.. Robots inspired by inchworms: structural design and applications J. Field Robot. 2025 rob.70087

[21] Plaut R. H.. Mathematical model of inchworm locomotion Int. J. Non-Linear Mech. 2015 76 56 63

[22] Shi Z.,Pan J.,Tian J.,Huang H.,Jiang Y.,Zeng S.. An inchworm-inspired crawling robot J. Bionic Eng. 2019 16 582 92

[23] Thomas S.,Germano P.,Martinez T.,Perriard Y.. An untethered mechanically-intelligent inchworm robot powered by a shape memory alloy oscillator Sens. Actuators A Phys. 2021 332 113115

[24] Luo L.,Zhang F.,Wang L.,Liu Y.,Leng J.. Recent advances in shape memory polymers: multifunctional materials, multiscale structures, and applications Adv. Funct. Mater. 2023 34 2312036

[25] Felton S. M.,Tolley M. T.,Onal C. D.,Rus D.,Wood R. J.. Robot self-assembly by folding: a printed inchworm robot. In 2013 IEEE International Conference on Robotics and Automation (ICRA), Karlsruhe, Germany, May 6-10, 2013; IEEE, 2013, pp 277-82

[26] Conn A. T.,Hinitt A. D.,Wang P.. Soft segmented inchworm robot with dielectric elastomer muscles. In SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, San Diego, California, USA; Bar-cohen, Y., Eds.; pp 90562L

[27] Cao J.,Liang W.,Wang Y.,Lee H. P.,Zhu J.,Ren Q.. Control of a soft inchworm robot with environment adaptation IEEE Trans. Ind. Electron. 2020 67 3809 18

[28] Kang H.,Li Z.,Sun Y.,Yu Q.,Yang X.. Model of the longitudinal-shear piezoelectric inchworm motor in shear movement Int. J. Mech. Sci. 2024 269 109033

[29] Guan J.,Zhang S.,Deng J.,Liu J.,Liu Y.. A driving-clamping integrated inchworm linear piezoelectric actuator with miniaturization and high thrust density IEEE Trans. Ind. Electron. 2025 72 801 10

[30] Wang R.,Hu Y.,Shen D.,Ma J.,Li J.,Wen J.. A novel piezoelectric inchworm actuator driven by one channel direct current signal IEEE Trans. Ind. Electron. 2021 68 2015 23

[31] Pfeil S.,Henke M.,Katzer K.,Zimmermann M.,Gerlach G.. A worm-like biomimetic crawling robot based on cylindrical dielectric elastomer actuators Front. Robot. AI 2020 7 9 PMC7805930

[32] Wu C.,Liu H.,Lin S.,Lam J.,Xi N.,Chen Y.. Shape morphing of soft robotics by pneumatic torsion strip braiding Nat. Commun. 2025 16 3787 PMC12015459

[33] Zhong Y.,Xie X.,Zhu J.,Wu K.,Wang C.. Biomimetic crawling robot based on dielectric elastomer: design, modeling and experiment IEEE Robot. Autom. Lett. 2024 9 9669 76

[34] Wang Y.,Gregory C.,Minor M. A.. Improving mechanical properties of molded silicone rubber for soft robotics through fabric compositing Soft Robot. 2018 5 272 90

[35] Hu J.,Chen S.,Wang L.. A new insect-scale piezoelectric robot with asymmetric structure IEEE Trans. Ind. Electron. 2023 70 8194 202

[36] Lobontiu N.,Goldfarb M.,Garcia E.. A piezoelectric-driven inchworm locomotion device Mech. Mach. Theory 2001 36 425 43

[37] Chen E.,Yang Y.,Li M..et al. Bio-mimic, fast-moving, and flippable soft piezoelectric robots Adv. Sci. (Weinh). 2023 10 e2300673 PMC10369280

[38] Yang Y.,Tse Y. A.,Zhang Y.,Kan Z.,Wang M. Y.. A low-cost inchworm-inspired soft robot driven by supercoiled polymer artificial muscle. In 2019 2nd IEEE International Conference on Soft Robotics (RoboSoft), Seoul, Korea (South), April 14-18, 2019; IEEE, 2019, pp 161-6.

[39] Xie D.,Liu J.,Kang R.,Zuo S.. Fully 3D-printed modular pipe-climbing robot IEEE Robot. Autom. Lett. 2021 6 462 9

[40] Ze Q.,Kuang X.,Wu S..et al. Magnetic shape memory polymers with integrated multifunctional shape manipulation Adv. Mater. 2020 32 e1906657

[41] Qu X.,Sun H.,Kan X..et al. Temperature-sensitive and solvent-resistance hydrogel sensor for ambulatory signal acquisition in “moist/hot environment” Nano Res. 2023 16 10348 57

[42] Aydin O.,Zhang X.,Nuethong S..et al. Neuromuscular actuation of biohybrid motile bots Proc. Natl. Acad. Sci. U.S.A. 2019 116 19841 7 PMC6778261

[43] Yeo S.,Chen I.,Senanayake R. S.,Wong P. S.. Design and development of a planar inchworm robot. In 17th International Symposium on Automation and Robotics in Construction, Taipei, Taiwan, September 18-20, 2000.

[44] Guo H.,Zhang J.,Wang T.,Li Y.,Hong J.,Li Y.. Design and control of an inchworm-inspired soft robot with omega-arching locomotion. In 2017 IEEE International Conference on Robotics and Automation (ICRA), Singapore, Singapore, May 29 - June 3, 2017; IEEE, 2017, pp 4154-9.

[45] Ning J.,Ti C.,Liu Y.. Inchworm inspired pneumatic soft robot based on friction hysteresis J. Robotics Autom. 2017 1 54 63

[46] Manfredi L.,Capoccia E.,Ciuti G.,Cuschieri A.. A soft pneumatic inchworm double balloon (SPID) for colonoscopy Sci. Rep. 2019 9 11109 PMC6668406

[47] Xia D.,Zhang L.,Nong W.,Duan Q.,Ding J.. 3D-printed soft bionic inchworm robot powered by magnetic force Biomimetics (Basel). 2025 10 202 PMC12025109

[48] Moreira F.,Abundis A.,Aguirre M.,Castillo J.,Bhounsule P. A.. An inchworm-inspired robot based on modular body, electronics and passive friction pads performing the two-anchor crawl gait J. Bionic Eng. 2018 15 820 6

[49] Karipoth P.,Christou A.,Pullanchiyodan A.,Dahiya R.. Bioinspired inchworm- and earthworm-like soft robots with intrinsic strain sensing Adv. Intell. Syst. 2021 4 2100092

[50] Lin D.,Yang F.,Gong D.,Li R.. Bio-inspired magnetic-driven folded diaphragm for biomimetic robot Nat. Commun. 2023 14 163 PMC9834404

[51] Tang Y.,Chi Y.,Sun J..et al. Leveraging elastic instabilities for amplified performance: Spine-inspired high-speed and high-force soft robots Sci. Adv. 2020 6 eaaz6912

[52] Yuan Y.,Lu W.,Kao C.,Hung J.,Lin P.. Design and implementation of an inchworm robot. In 2016 International Conference on Advanced Robotics and Intelligent Systems (ARIS), Taipei, Taiwan, August 31 - September 2, 2016; IEEE, 2016, pp 1-1

[53] Shin B.,Ha J.,Lee M..et al. Hygrobot: a self-locomotive ratcheted actuator powered by environmental humidity Sci. Robot. 2018 3 eaar2629

[54] Yu X.,Wang J.,Su J.,Song S.. Inchworm-like biomimetic magnetic-driven robotic shell for capsule endoscope in a tubular environment IEEE/ASME Trans. Mechatron. 2025 30 2234 44

[55] Chen Z.,Ha J.,Lee M..et al. Inchworm-inspired micro-inspection robot: autonomous design for aero-engine inspection Sens. Actuat. A-Phys. 2025 391 116589

[56] Zheng Z.,Cheng H.,Kumar P..et al. Piezoelectric soft robots for inchworm crawling and jumping optimized with weight asymmetry IEEE Trans. Ind. Electron. 2023 70 8203 11 Available from: https://www.spp2100.de/fileadmin/images/ICRA22__Contributed_Papers/11_Zheng_icra_2022_workshop_soft_robot.pdf (accessed 2026-1-27)