Quadrupeds

@article{gregory1912notes,
    author = "Gregory, William K.",
    title = "NOTES ON THE PRINCIPLES OF QUADRUPEDAL LOCOMOTION AND ON THE MECHANISM OF HE LIMBS IN HOOFED ANIMALS",
    year = "1912",
    journal = "Annals of the New York Academy of Sciences",
    url = "https://doi.org/10.1111/j.1749-6632.1912.tb55164.x",
    doi = "10.1111/j.1749-6632.1912.tb55164.x",
    number = "1",
    pages = "267-294",
    volume = "22"
}

@misc{gregory1912notes1,
    author = "Gregory, W. K",
    title = "Notes on the principles of quadrupedal locomotion and the mechanisms of the limbs in hoofed animals",
    year = "1912",
    howpublished = "Annals of the New York Academy of Sciences, v. 22, p. 267-292",
    note = "talkorigins\_source = {true}; raw\_reference = {Gregory, W. K., 1912, Notes on the principles of quadrupedal locomotion and the mechanisms of the limbs in hoofed animals: Annals of the New York Academy of Sciences, v. 22, p. 267-292.}"
}

@article{gans1962terrestrial,
    author = "GANS, CARL",
    title = "TERRESTRIAL LOCOMOTION WITHOUT LIMBS",
    year = "1962",
    journal = "American Zoologist",
    url = "https://doi.org/10.1093/icb/2.2.167",
    doi = "10.1093/icb/2.2.167",
    number = "2",
    pages = "167-182",
    volume = "2"
}

@incollection{crossref1983chapter,
    title = "CHAPTER 7 Four Limbs and Quadrupeds",
    year = "1983",
    booktitle = "The Order of Man",
    url = "https://doi.org/10.1515/9789882202368-008",
    doi = "10.1515/9789882202368-008",
    pages = "203-226"
}

We develop an integrated set of gaits and skills for a physics-based simulation of a quadruped. The motion repertoire for our simulated dog includes walk, trot, pace, canter, transverse gallop, rotary gallop, leaps capable of jumping on-and-off platforms and over obstacles, sitting, lying down, standing up, and getting up from a fall. The controllers use a representation based on gait graphs, a dual leg frame model, a flexible spine model, and the extensive use of internal virtual forces applied via the Jacobian transpose. Optimizations are applied to these control abstractions in order to achieve robust gaits and leaps with desired motion styles. The resulting gaits are evaluated for robustness with respect to push disturbances and the traversal of variable terrain. The simulated motions are also compared to motion data captured from a filmed dog.

@article{coros2011locomotion,
    author = "Coros, Stelian and Karpathy, Andrej and Jones, Ben and Reveret, Lionel and van de Panne, Michiel",
    title = "Locomotion skills for simulated quadrupeds",
    year = "2011",
    journal = "ACM Transactions on Graphics",
    abstract = "We develop an integrated set of gaits and skills for a physics-based simulation of a quadruped. The motion repertoire for our simulated dog includes walk, trot, pace, canter, transverse gallop, rotary gallop, leaps capable of jumping on-and-off platforms and over obstacles, sitting, lying down, standing up, and getting up from a fall. The controllers use a representation based on gait graphs, a dual leg frame model, a flexible spine model, and the extensive use of internal virtual forces applied via the Jacobian transpose. Optimizations are applied to these control abstractions in order to achieve robust gaits and leaps with desired motion styles. The resulting gaits are evaluated for robustness with respect to push disturbances and the traversal of variable terrain. The simulated motions are also compared to motion data captured from a filmed dog.",
    url = "https://doi.org/10.1145/2010324.1964954",
    doi = "10.1145/2010324.1964954",
    number = "4",
    pages = "1-12",
    volume = "30"
}

@inproceedings{godage2012locomotion,
    author = "Godage, Isuru S. and Nanayakkara, Thrishantha and Caldwell, Darwin G.",
    title = "Locomotion with continuum limbs",
    year = "2012",
    booktitle = "2012 IEEE/RSJ International Conference on Intelligent Robots and Systems",
    url = "https://doi.org/10.1109/iros.2012.6385810",
    doi = "10.1109/iros.2012.6385810",
    pages = "293-298"
}

In quadrupeds, the most critical aspect of postural control during locomotion is lateral stability. However, neural mechanisms underlying lateral stability are poorly understood. Here, we studied lateral stability in decerebrate cats walking on a treadmill with their hindlimbs. Two destabilizing factors were used: a brief lateral push of the cat and a sustained lateral tilt of the treadmill. It was found that the push caused considerable trunk bending and twisting, as well as changes in the stepping pattern, but did not lead to falling. Due to postural reactions, locomotion with normal body configuration was restored in a few steps. It was also found that the decerebrate cat could keep balance during locomotion on the laterally tilted treadmill. This postural adaptation was based on the transformation of the symmetrical locomotor pattern into an asymmetrical one, with different functional lengths of the right and left limbs. Then, we analyzed limb and trunk neural mechanisms contributing to postural control during locomotion. It was found that one of the limb mechanisms operates in the transfer phase and secures a standard (relative to the trunk) position for limb landing. Two other limb mechanisms operate in the stance phase; they counteract distortions of the locomotor pattern by regulating the limb stiffness. The trunk configuration mechanism controls the body shape on the basis of sensory information coming from trunk afferents. We suggest that postural reactions generated by these four mechanisms are integrated, thus forming a response of the whole system to perturbation of balance during locomotion.

@article{musienko2014limb,
    author = "Musienko, Pavel E. and Deliagina, Tatiana G. and Gerasimenko, Yury P. and Orlovsky, Grigori N. and Zelenin, Pavel V.",
    title = "Limb and Trunk Mechanisms for Balance Control during Locomotion in Quadrupeds",
    year = "2014",
    journal = "The Journal of Neuroscience",
    abstract = "In quadrupeds, the most critical aspect of postural control during locomotion is lateral stability. However, neural mechanisms underlying lateral stability are poorly understood. Here, we studied lateral stability in decerebrate cats walking on a treadmill with their hindlimbs. Two destabilizing factors were used: a brief lateral push of the cat and a sustained lateral tilt of the treadmill. It was found that the push caused considerable trunk bending and twisting, as well as changes in the stepping pattern, but did not lead to falling. Due to postural reactions, locomotion with normal body configuration was restored in a few steps. It was also found that the decerebrate cat could keep balance during locomotion on the laterally tilted treadmill. This postural adaptation was based on the transformation of the symmetrical locomotor pattern into an asymmetrical one, with different functional lengths of the right and left limbs. Then, we analyzed limb and trunk neural mechanisms contributing to postural control during locomotion. It was found that one of the limb mechanisms operates in the transfer phase and secures a standard (relative to the trunk) position for limb landing. Two other limb mechanisms operate in the stance phase; they counteract distortions of the locomotor pattern by regulating the limb stiffness. The trunk configuration mechanism controls the body shape on the basis of sensory information coming from trunk afferents. We suggest that postural reactions generated by these four mechanisms are integrated, thus forming a response of the whole system to perturbation of balance during locomotion.",
    url = "https://doi.org/10.1523/jneurosci.4663-13.2014",
    doi = "10.1523/jneurosci.4663-13.2014",
    number = "16",
    pages = "5704-5716",
    volume = "34"
}

@incollection{crossref2021limbs,
    title = "Limbs and Locomotion",
    year = "2021",
    booktitle = "A Natural History of Amphibians",
    url = "https://doi.org/10.2307/j.ctv1nxcv5j.8",
    doi = "10.2307/j.ctv1nxcv5j.8",
    pages = "26-32"
}

@incollection{whitaker2021timing,
    author = "Whitaker, Harold and Halas, John and Sito, Tom",
    title = "Timing Animals' Movements: Other Quadrupeds",
    year = "2021",
    booktitle = "Timing for Animation, 40th Anniversary Edition",
    url = "https://doi.org/10.1201/9781003139706-59",
    doi = "10.1201/9781003139706-59",
    pages = "110-111"
}

@inproceedings{pollayil2022planning,
    author = "Pollayil, Mathew Jose and Santina, Cosimo Della and Mesesan, George and Englsberger, Johannes and Seidel, Daniel and Garabini, Manolo and Ott, Christian and Bicchi, Antonio and Albu-Schaffer, Alin",
    title = "Planning Natural Locomotion for Articulated Soft Quadrupeds",
    year = "2022",
    booktitle = "2022 International Conference on Robotics and Automation (ICRA)",
    url = "https://doi.org/10.1109/icra46639.2022.9812416",
    doi = "10.1109/icra46639.2022.9812416",
    pages = "6593-6599"
}