Spine Controller for a Sprawling Posture Robot

Horvat, Tomislav; Melo, Kamilo; Ijspeert, Auke Jan

doi:10.1109/lra.2017.2664898

Cited by 24 publications

(17 citation statements)

References 18 publications

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“…Ijspeert et al (2007) showed that CPGs can produce body–limb coordinated movements for the locomotion of a salamander robot, as well as generate gait transitions among different forward gait motions of varying speeds. Using CPG analytic tools, Crespi et al (2013), Horvat et al (2017), and Eckert et al (2015) demonstrated that the body–limb coordination used by salamanders optimizes their forward speed and produce turning motion. Following this idea, Owaki et al (2013) investigated the mechanisms of inter-limb coordination which exhibit good adaptability to changes in walking speed of a quadrupedal robot.…”

Section: Related Workmentioning

confidence: 99%

Coordination of lateral body bending and leg movements for sprawled posture quadrupedal locomotion

Chong

Ozkan-Aydin

Gong³

et al. 2021

The International Journal of Robotics Research

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Many animals generate propulsive forces by coordinating legs, which contact and push against the surroundings, with bending of the body, which can only indirectly influence these forces. Such body–leg coordination is not commonly employed in quadrupedal robotic systems. To elucidate the role of back bending during quadrupedal locomotion, we study a model system: the salamander, a sprawled-posture quadruped that uses lateral bending of the elongate back in conjunction with stepping of the limbs during locomotion. We develop a geometric approach that yields a low-dimensional representation of the body and limb contributions to the locomotor performance quantified by stride displacement. For systems where the damping forces dominate inertial forces, our approach offers insight into appropriate coordination patterns, and improves the computational efficiency of optimization techniques. In particular, we demonstrate effect of the lateral undulation coordinated with leg movement in the forward, rotational, and lateral directions of the robot motion. We validate the theoretical results using numerical simulations, and then successfully test these approaches using robophysical experiments on granular media, a model deformable, frictional substrate. Although our focus lies primarily on robotics, we also demonstrate that our tools can accurately predict optimal body bending of a living salamander Salamandra salamandra.

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Section: Related Workmentioning

confidence: 99%

Coordination of lateral body bending and leg movements for sprawled posture quadrupedal locomotion

Chong

Ozkan-Aydin

Gong³

et al. 2021

The International Journal of Robotics Research

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“…Bem et al ( 2003 ) have modeled the swimming salamander as a chain of ten links, corresponding roughly to three trunk joints and no limbs. The most accurate model has five joints between the girdles and four DOFs in each limb (Karakasiliotis et al, 2016 ; Horvat and Ijspeert, 2017 ; Horvat et al, 2017 ). Mechanical properties (damping and elasticity) of the body tissues were included in the muscle models used by Ijspeert ( 2001 ; 2005 ) Bem et al ( 2003 ), Harischandra et al ( 2010 , 2011 ), and Liu et al ( 2018 , 2020 ), and in the controller of Suzuki et al ( 2019b ).…”

Section: Related Modeling Workmentioning

confidence: 99%

“…The effect of sensory feedback on the activity of the salamander CPG has only been investigated in simulation (Bem et al, 2003 ; Ijspeert et al, 2005 ; Harischandra et al, 2011 ; Liu et al, 2020 ). The role of sensory feedback in body-limb coordination has also been investigated using controllers without CPG, both in simulations (Horvat and Ijspeert, 2017 ) and with a robot (Suzuki et al, 2019a ).…”

Section: Related Modeling Workmentioning

confidence: 99%

Reproducing Five Motor Behaviors in a Salamander Robot With Virtual Muscles and a Distributed CPG Controller Regulated by Drive Signals and Proprioceptive Feedback

et al. 2020

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Diverse locomotor behaviors emerge from the interactions between the spinal central pattern generator (CPG), descending brain signals and sensory feedback. Salamander motor behaviors include swimming, struggling, forward underwater stepping, and forward and backward terrestrial stepping. Electromyographic and kinematic recordings of the trunk show that each of these five behaviors is characterized by specific patterns of muscle activation and body curvature. Electrophysiological recordings in isolated spinal cords show even more diverse patterns of activity. Using numerical modeling and robotics, we explored the mechanisms through which descending brain signals and proprioceptive feedback could take advantage of the flexibility of the spinal CPG to generate different motor patterns. Adapting a previous CPG model based on abstract oscillators, we propose a model that reproduces the features of spinal cord recordings: the diversity of motor patterns, the correlation between phase lags and cycle frequencies, and the spontaneous switches between slow and fast rhythms. The five salamander behaviors were reproduced by connecting the CPG model to a mechanical simulation of the salamander with virtual muscles and local proprioceptive feedback. The main results were validated on a robot. A distributed controller was used to obtain the fast control loops necessary for implementing the virtual muscles. The distributed control is demonstrated in an experiment where the robot splits into multiple functional parts. The five salamander behaviors were emulated by regulating the CPG with two descending drives. Reproducing the kinematics of backward stepping and struggling however required stronger muscle contractions. The passive oscillations observed in the salamander's tail during forward underwater stepping could be reproduced using a third descending drive of zero to the tail oscillators. This reduced the drag on the body in our hydrodynamic simulation. We explored the effect of local proprioceptive feedback during swimming and forward terrestrial stepping. We found that feedback could replace or reduce the need for different drives in both cases. It also reduced the variability of intersegmental phase lags toward values appropriate for locomotion. Our work suggests that different motor behaviors do not require different CPG circuits: a single circuit can produce various behaviors when modulated by descending drive and sensory feedback.

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“…Some animals have adapted their locomotion to multiple environments, and are able to change their gait, or switch from walking to swimming or crawling to fit their surroundings. Amphibious robot designs with a salamander or crocodile‐like morphology (Gu, Guo, Peng, Chen, & Yu, ; Horvat et al, , 2015) can switch between sprawling‐posture walking and shallow‐water swimming. While these designs present challenges for controlling gait on a platform with a segmented spine, they offer the possibility to navigate in small or difficult to access areas, over uneven terrain (Horvat, Melo, & Ijspeert, 2017a), as well as in water environments (e.g., flooded buildings and cluttered pipes).…”

Section: State Of the Artmentioning

confidence: 99%

The current state and future outlook of rescue robotics

Delmerico

Mintchev

Giusti

et al. 2019

Journal of Field Robotics

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241

124

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Robotic technologies, whether they are remotely operated vehicles, autonomous agents, assistive devices, or novel control interfaces, offer many promising capabilities for deployment in real-world environments. Postdisaster scenarios are a particularly relevant target for applying such technologies, due to the challenging conditions faced by rescue workers and the possibility to increase their efficacy while decreasing the risks they face. However, field-deployable technologies for rescue work have requirements for robustness, speed, versatility, and ease of use that may not be matched by the state of the art in robotics research. This paper aims to survey How to cite this article: Delmerico J, Mintchev S, Giusti A, et al. The current state and future outlook of rescue robotics.

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Spine Controller for a Sprawling Posture Robot

Cited by 24 publications

References 18 publications

Coordination of lateral body bending and leg movements for sprawled posture quadrupedal locomotion

Coordination of lateral body bending and leg movements for sprawled posture quadrupedal locomotion

Reproducing Five Motor Behaviors in a Salamander Robot With Virtual Muscles and a Distributed CPG Controller Regulated by Drive Signals and Proprioceptive Feedback

The current state and future outlook of rescue robotics

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