Simulation of autonomous rhythm and gait generation in quadrupedal locomotion with hindlegs
Online Journal (Open Access)
Abstract
Intending to reduce the complexity in quadrupedal locomotion planning and control through emergence even more, we propose a legged locomotion controller inspired by the sensorimotor functions observed in the cat spinal cord. In simulations using a hind-legged biped robot, we demonstrate the emergence of a rhythm and gait closely resembling the belt-driven locomotion observed in spinal cats. We also show the self-propulsive locomotion of this hind-legged biped, based on the hypothesis that the brainstem output directs the intensity of muscle contraction (locomotion power) to the spinal cord. Furthermore, we meticulously examine the dynamic interaction with the environment, considering the fixture's presence, and document the entire process in detail. We show that the mechanisms underlying the emergence of legged locomotion are the interactions between leg phase switching, self-excited oscillations of the body or trunk, and leg load spatiotemporal pattern. Its temporal pattern determines the rhythm, and its spatial pattern determines the gait.
Locomotion of a spinal cat with hindlimbs on a treadmill
- Spinal Cat Movie (.mp4 with narration) from the video "The basal ganglia and brainstem locomotor control, at 1min. 31sec., E. Garcia-Rill eds., 1989"
- (at 6sec.) a spinal cat supported manually at the chest and the tail
- (6sec.-- ) walking in the gait of out-of-phase coordination at slow belt speed
- (15sec.-- ) onset of slow motion
- (at 22sec.) slight pitching motion of the trunk induced by the increase of belt speed
- (24-27sec.) running of out-of-phase (the narration used 'walk to trot' at 26sec.)
- (28sec.-- ) running of in-phase (slight phase difference) with pitching motion of the trunk and kicking motion of legs at medium belt speed
- (46sec.-- ) running of in-phase (exactly) with large pitching motion of the trunk at high belt speed
- Reference
- H. Forssberg, S. Grillner and J. Halbertsma: ``The locomotion of the low spinal cat. I. Coordination within a hindlimb,'' Acta Physiol. Scand., vol.108, pp.269--281, 1980. [DOI:10.1111/j.1748-1716.1980.tb06533.x]
- H. Forssberg, S. Grillner, J. Halbertsma and S. Rossignol: ``The locomotion of the low spinal cat. II. Interlimb coordination,'' Acta Physiol. Scand., vol.108, pp.283--295, 1980. [doi:10.1111/j.1748-1716.1980.tb06534.x]
Locomotion of midbrain (and thalamic) cats on a treadmill
- Midbrain Cats Movie (.mp4 with narration). The reproduction (the trot gait only) of the mid-brain cat experiments (Shik et al. 1966) by Jordan and Steeves (1976) including the spontaneous hindlimbs stepping of a thalamic cat, from the video "The basal ganglia and brainstem locomotor control, E. Garcia-Rill eds., 1989"
Simulations of Emergent Locomotion Based on Sensorimotor Functions (mp4), including
- Self-Propelled locomotion with hindlimbs on the floor
- Belt-Driven locomotion with hindlimbs on a treadmill
- Quadrupedal locomotion on the floor: (while walking) transition from walk to trot gaits & (while trotting) transition from walking to running
Related Materials
- Section 2.1
- (Kimura et al. 1990) Gait transition from the trot to pace of 'Collie2' (mp4 with narration, PDF)
- (Fukuoka et al. 2003) Gait transition from the walk to trot of 'Tekken1' (mp4)
- emergence of rhythm and gait based on the self-excited body oscillation
- (Maufroy et al. 2012) Experiment of self-excitedly generated walking (mp4)
- Section 9.3
- "Our objective in the subsequent step is to elucidate the autonomous generation of the rhythm and gait of a quadruped ..."
- Autonomous gait transition from WALK to TROT induced by sensorimotor functions as speed increased (please see the last animation of mp4)
(preliminary study of quadrupedal locomotion)
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