title: A galloping quadruped model using left-right asymmetry in touchdown angles.
abstract: Among quadrupedal gaits, the galloping gait has specific characteristics in terms of locomotor behavior. In particular, it shows a left-right asymmetry in gait parameters such as touchdown angle and the relative phase of limb movements. In addition, asymmetric gait parameters show a characteristic dependence on locomotion speed. There are two types of galloping gaits in quadruped animals: the transverse gallop, often observed in horses; and the rotary gallop, often observed in dogs and cheetahs. These two gaits have different footfall sequences. Although these specific characteristics in quadrupedal galloping gaits have been observed and described in detail, the underlying mechanisms remain unclear. In this paper, we use a simple physical model with a rigid body and four massless springs and incorporate the left-right asymmetry of touchdown angles. Our simulation results show that our model produces stable galloping gaits for certain combinations of model parameters and explains these specific characteristics observed in the quadrupedal galloping gait. The results are then evaluated in comparison with the measured data of quadruped animals and the gait mechanisms are clarified from the viewpoint of dynamics, such as the roles of the left-right touchdown angle difference in the generation of galloping gaits and energy transfer during one gait cycle to produce two different galloping gaits.
authors.affiliation: Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan.
authors.forename: Masayasu
authors.initials: M
authors.lastname: Tanase
authors.affiliation: Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ambe
authors.affiliation: Department of Aeronautics and Astronautics, Graduate School of Engineering, Kyoto University, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan; JST, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan. Electronic address: shinya_aoi@kuaero.kyoto-u.ac.jp.
authors.forename: Shinya
authors.initials: S
authors.lastname: Aoi
authors.affiliation: Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan.
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Matsuno
mesh_terms: D062365:Aminobenzoates; D000818:Animals; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D004285:Dogs; D005684:Gait; D006041:Goats; D006736:Horses; D062385:Hydroxybenzoates; D008954:Models, Biological; D012420:Running
chemical_list: D062365:Aminobenzoates; D062385:Hydroxybenzoates; C110924:3-amino-4-hydroxybenzoic acid
keywords: Center of mass movement; Energy transfer; Galloping gait; Left–right asymmetry; Model; Quadruped; Touchdown angle