Science China Technological Sciences

, Volume 62, Issue 4, pp 619–627 | Cite as

Self-centering characteristics of a petal-shaped capsule robot

  • YongShun ZhangEmail author
  • Jun Chen
  • Yu Zhang
  • Kang Meng


Based on the multiple wedge effects, a petal-shaped capsule robot (PCR) is proposed, and the self-centering phenomenon of the PCR is discovered. For investigating the self-centering characteristics, an innovative concept of the instantaneous fluid membrane (FM) thickness, along with the dynamic FM thickness, is proposed; thus a dynamic FM thickness model and a hydrodynamic pressure (HP) model are derived when the PCR axis deviates from the pipe axis under the effect of gravity. A kinematics equation during suspending process in the vertical direction and a swimming kinematics equation in axial direction are derived respectively. Four capsule robots with different eccentricities of the tiles were manufactured and tested, the theoretical and experimental results show that the HP gradient is a fundamental reason for the self-centering phenomenon. The PCR with the self-centering ability can directly avoid the contact with the bottom of the gastrointestinal (GI) tract, achieving the excellent obstacle surmounting ability in the GI complex environment with the less twisted impact on the GI tract, which has a promising application prospect in the GI diagnosis.


petal-shaped capsule robot self-centering characteristics multiple wedge effects complete suspension phenomenon 


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Copyright information

© Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Key Laboratory for Precision & Non-traditional Machining Technology of Ministry of EducationDalian University of TechnologyDalianChina
  2. 2.School of Computer Science and Technology, Faculty of Electronic Information and Electrical EngineeringDalian University of TechnologyDalianChina

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