The robotic approach to the passive interlocking mechanism in the hindlimb musculoskeletal system of <i>Crocodylus porosus</i>

摘要

AbstractEfficient locomotion in terrestrial vertebrates relies on intra-limb coordination that emerges through interaction with the environment and passive interlocking of the musculoskeletal system. These structures have been well investigated in some mammals and birds, but the presence of similar structures in other terrestrial vertebrates has been under appreciated. This study addresses the functionality of the passive interlocking system in reptilian hindlimb locomotion by dissecting Crocodylus porosus and constructing a robot. Based on the dissection, we hypothesized that the passive interlocking mechanism consisted of multiple muscles to maintain the semi-erect limb posture and support its weight. The mechanism is provided by the caudifemoralis longus muscle, along with its tendon and the gastrocnemius externus, acting as a passive element that interacts with the ground reaction force. Accordingly, the feasibility of the interlocking function was demonstrated by a robot implementing the hindlimb and pelvic musculoskeletal system of crocodilians. This study provides new insights into the locomotion mechanism of crocodilians and emphasizes the importance of passive interlocking in efficient locomotion in terrestrial vertebrates. The findings could have implications for developing biomimetic robots and understanding the evolution of terrestrial locomotion in vertebrates.Keywords: Crocodilian hindlimb robotpassive interlocking mechanismbiomechanicsmusculoskeletal system AcknowledgementsAdditionally, we would like to express our gratitude to Keiichiro Kamizuki of the Tetsunoyu Oniyama Hotel and Yasutuna Utsunomiya of the Oniyama Jigoku for providing the Crocodylus porous.Disclosure statementNo potential conflict of interest was reported by the author(s).Correction StatementThis article has been corrected with minor changes. These changes do not impact the academic content of the article.Additional informationFundingThis research was supported by JST Support for Pioneering Research Initiated by the Next Generation (SPRING), Grant Numbers [JPMJSP2138, JSPS KAKENHI, 20K04390 and 23K03765] and Grant for Promotion of OUS Research Projects [Grant Number OUS-RP-20-2].Notes on contributorsKazuki ItoKazuki Ito received the B.S. and M.S. degrees from Department of Mechanical Engineering, Okayama University of Science, Japan, in 2019 and 2021 respectively. He is a Ph.D. Student at Osaka University. His research interests include biomechanics. He is a member of the Robot Society of Japan (RSJ), Japan Society of Mechanical Engineers (JSME), and Paleontological Society of Japan (PSJ).Tetsuya KinugasaTetsuya Kinugasa received his B.Sc., M.Sc., and Ph.D. degrees from Department of Mechanical Engineering, Osaka Prefecture University, Japan, in 1994, 1996, and 1999. He is a Professor at Department of Mechanical Systems Engineering, Okayama University of Science. His research interests include biomechanics, legged locomotion, and field robotics. He is a member of the Robot Society of Japan (RSJ), the Japan Society of Mechanical Engineers (JSME), the Institute of Systems, Control and Information Engineers, the Institute of Electrical and Electronics Engineers (IEEE), and the Paleontological Society of Japan (PSJ).Kentaro ChibaKentaro Chiba received B.Sc. from Department of Earth Science, Tohoku University, Japan in 2008 and received M.Sc. from Department of Earth and Planetary Sciences, Hokkaido University, Japan in 2011. He received Ph.D. from Department of Ecology and Evolutionary Biology in 2018. He is a lecturer at Okayama University of Science. His research interests include dinosaur paleobiology and evolution. He is a member of the Society of Vertebrate Paleontology, Canadian Society of Vertebrate Paleontology, and the Paleontological Society of Japan.Yu OkudaYu Okuda received the B.Sc. and M.Sc. degrees from Biosphere-Geosphere Science, Okayama University of Science, Japan, in 2007 and 2009 respectively. She received the Doctoral degree i