How the CNS deals with instability of upright posture is the core in the control of bipedal gait. In this review, we summarize our recent findings comparing kinematics and EMG activity during quadrupedal and bipedal gait in Japanese macaques. Trunk/hindlimb muscles showed step cycle-modulated activity, which was more active in bipedal than in quadrupedal gait. For bipedal gait, enhanced activity during longer double support phase was predominantly observed in distal hindlimb muscles. Alternate burst activity in bilateral back muscles cyclically brought back the tilted trunk. In monkeys' quadrupedal gait, hindlimbs formed functional pairs with contralateral forelimbs, unlike in non-primate quadrupeds. These diagonal pairs acted differently on movements of the center of mass (COM). For bipedal gait, the hindlimbs solely carried the COM. Our results suggest that, compared to non-primate quadrupeds, hindlimbs in macaques contribute more critically to weight support and balance control even for quadrupedal gait. Additionally, for more unstable bipedal gait, the monkeys' CNS reinforces such hindlimb roles and actively controls the trunk posture in maintaining dynamic balance, in a manner similar to humans. Studies on Japanese macaques will further our understanding of the neural basis for the control of gait in mammals by bridging non-primate quadrupeds and humans.
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http://dx.doi.org/10.11477/mf.1416202188 | DOI Listing |
Gels
December 2024
Department of Mechanics and Engineering Science, School of Physics, Nanjing University of Science and Technology, Nanjing 210094, China.
Magnetic hydrogel soft robots have shown great potential in various fields. However, their contact dynamic behaviors are complex, considering stick-slip motion at the contact interface, and lack accurate computational models to analyze them. This paper improves the numerical computational method for hydrogel materials with magneto-mechanical coupling effect, analyses the inchworm-like contact motion of the biomimetic bipedal magnetic hydrogel soft robot, and designs and optimizes the robot's structure.
View Article and Find Full Text PDFBiomimetics (Basel)
January 2025
Institute of Automation, Chinese Academy of Sciences, Beijing 100089, China.
With advancements in bipedal locomotion for humanoid robots, a critical challenge lies in generating gaits that are bounded to ensure stable operation in complex environments. Traditional Model Predictive Control (MPC) methods based on Linear Inverted Pendulum (LIP) or Cart-Table (C-T) methods are straightforward and linear but inadequate for robots with flexible joints and linkages. To overcome this limitation, we propose a Flexible MPC (FMPC) framework that incorporates joint dynamics modeling and emphasizes bounded gait control to enable humanoid robots to achieve stable motion in various conditions.
View Article and Find Full Text PDFBiomimetics (Basel)
January 2025
Graduate School of Information, Production and Systems, Waseda University, 2-7 Hibikino, Wakamatsu-ku, Kitakyushu 808-0135, Japan.
In recent years, humanoid robot technology has been developing rapidly due to the need for robots to collaborate with humans or replace them in various tasks, requiring them to operate in complex human environments and placing high demands on their mobility. Developing humanoid robots with human-like walking and hopping abilities has become a key research focus, as these capabilities enable robots to move and perform tasks more efficiently in diverse and unpredictable environments, with significant applications in daily life, industrial operations, and disaster rescue. Currently, methods based on hybrid zero dynamics and reinforcement learning have been employed to enhance the walking and hopping capabilities of humanoid robots; however, model predictive control (MPC) presents two significant advantages: it can adapt to more complex task requirements and environmental conditions, and it allows for various walking and hopping patterns without extensive training and redesign.
View Article and Find Full Text PDFGait Posture
January 2025
Sports Engineering / Movement Science Departement, Faculty for Human Sciences, Otto-von-Guericke University, Magdeburg, Germany.
Background: Postural stability is a key factor in maintaining an upright standing position. Children with average height (CAH) have elaborate general postural stability up to the age of seven years. Children with achondroplasia (ACH) face body disproportions like shorter arms and legs, bowing of the legs as well as hyperlordosis and hypokyphosis in the spine.
View Article and Find Full Text PDFSci Rep
January 2025
Chair of Applied Mechanics, Technical University of Munich, Garching, 85748, Germany.
Ankle push-off is important for efficient, human-like walking, and many prosthetic devices mimic push-off using motors or elastic elements. The knee is extended throughout the stance phase and begins to buckle just before push-off, with timing being crucial. However, the exact mechanisms behind this buckling are still unclear.
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