Dynamic Locomotion Gaits of a Compliantly Actuated Quadruped With SLIP-Like Articulated Legs Embodied in the Mechanical Design

Lakatos, Dominic; Ploeger, Kai; Loeffl, Florian; Seidel, Daniel; Schmidt, Florian; Gumpert, Thomas; John, Freia Irina; Bertram, Torsten; Albu‐Schäffer, Alin

doi:10.1109/lra.2018.2857511

Cited by 29 publications

(24 citation statements)

References 28 publications

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“…The static walking algorithm has been tested experimentally on DLR's compliantly actuated quadruped robot platform bert, which is described in detail in [20]. The robot is equipped with low-cost off-the-shelf servo drives, which are commanded through position control.…”

Section: Methodsmentioning

confidence: 99%

Using Elastically Actuated Legged Robots in Rough Terrain: Experiments with DLR Quadruped bert

Seidel

Hermann

Gumpert

et al. 2020

2020 IEEE Aerospace Conference

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This paper addresses walking and balancing in rough terrain for legged locomotion in planetary exploration as an alternative to the commonly used wheeled locomotion. In contrast to the latter, where active balancing is not necessary, legged locomotion requires constant effort to keep the main body stabilized during motion. While common quadrupedal robots require to carefully plan motions through torque control and force distribution, this paper presents an approach where elastic elements in the drive train function as an intrinsic balancing component that allows to ignore inaccuracies in the locomotion pattern and passively accommodate for terrain unevenness. The approach proposes a static walking gait algorithm, which is formulated for a general quadrupedal robot, and a hardware foot design to support the locomotion pattern. The method is experimentally tested on an elastically actuated quadrupedal robot.

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Section: Methodsmentioning

confidence: 99%

Using Elastically Actuated Legged Robots in Rough Terrain: Experiments with DLR Quadruped bert

Seidel

Hermann

Gumpert

et al. 2020

2020 IEEE Aerospace Conference

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“…To understand the underlying control principles that allow this joint coordination, this work regards a simplified scenario of one single biomimetic robotic leg during hopping. The leg chosen as test platform is part of the compliant quadruped robot Bert (Lakatos et al, 2018) developed at the German Aerospace Center (DLR). It had already served as test bed for investigations on compliant mechanisms and bioinspired control previously (Lakatos et al, 2015;Stratmann et al, 2016b) and will allow for easy extension of the investigated concepts on locomotion in the future.…”

Section: Biomimetic Robot Legmentioning

confidence: 99%

“…The generalized external forces are summarized by τ τ τ contact . For more details refer to Lakatos et al (2018).…”

Section: Biomimetic Robot Legmentioning

confidence: 99%

Adapting Highly-Dynamic Compliant Movements to Changing Environments: A Benchmark Comparison of Reflex- vs. CPG-Based Control Strategies

et al. 2021

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To control highly-dynamic compliant motions such as running or hopping, vertebrates rely on reflexes and Central Pattern Generators (CPGs) as core strategies. However, decoding how much each strategy contributes to the control and how they are adjusted under different conditions is still a major challenge. To help solve this question, the present paper provides a comprehensive comparison of reflexes, CPGs and a commonly used combination of the two applied to a biomimetic robot. It leverages recent findings indicating that in mammals both control principles act within a low-dimensional control submanifold. This substantially reduces the search space of parameters and enables the quantifiable comparison of the different control strategies. The chosen metrics are motion stability and energy efficiency, both key aspects for the evolution of the central nervous system. We find that neither for stability nor energy efficiency it is favorable to apply the state-of-the-art approach of a continuously feedback-adapted CPG. In both aspects, a pure reflex is more effective, but the pure CPG allows easy signal alteration when needed. Additionally, the hardware experiments clearly show that the shape of a control signal has a strong influence on energy efficiency, while previous research usually only focused on frequency alignment. Both findings suggest that currently used methods to combine the advantages of reflexes and CPGs can be improved. In future research, possible combinations of the control strategies should be reconsidered, specifically including the modulation of the control signal's shape. For this endeavor, the presented setup provides a valuable benchmark framework to enable the quantitative comparison of different bioinspired control principles.

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“…Even with this approach, we found differences that could not only be used as objective parameters for training aspects of dogs but also be used for future bioinspired robot developments and their validation (e.g. Buehler, 2002;Lakatos et al, 2018;Eckert et al, 2019).…”

Section: Limitations Of the Chosen Limb Modelmentioning

confidence: 99%

Limb dynamics in agility jumps of beginner and advanced dogs

Söhnel

Rode

Lussanet

et al. 2020

Journal of Experimental Biology

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A considerable body of work has examined the dynamics of different dog gaits, but there are no studies that have focused on limb dynamics in jumping. Jumping is an essential part of dog agility, a dog sport in which handlers direct their dogs through an obstacle course in a limited time. We hypothesized that limb parameters like limb length and stiffness indicate the skill level of dogs. We analyzed global limb parameters in jumping for 10 advanced and 10 beginner dogs. In experiments, we collected 3D kinematics and ground reaction forces during dog jumping at high forward speeds. Our results revealed general strategies of limb control in jumping and highlighted differences between advanced and beginner dogs. In takeoff , the spatially leading forelimb was 75% (P<0.001) stiffer than the trailing forelimb. In landing, the trailing forelimb was 14% stiffer (P<0.001) than the leading forelimb. This indicates a strut-like action of the forelimbs to achieve jumping height in takeoff and to transfer vertical velocity into horizontal velocity in landing (with switching roles of the forelimbs). During landing, the more (24%) compliant forelimbs of beginner dogs (P=0.005) resulted in 17% (P=0.017) higher limb compression during the stance phase. This was associated with a larger amount of eccentric muscle contraction, which might in turn explain the soft tissue injuries that frequently occur in the shoulder region of beginner dogs. For all limbs, limb length at toe-off was greater for advanced dogs. Hence, limb length and stiffness might be used as objective measures of skill.

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Dynamic Locomotion Gaits of a Compliantly Actuated Quadruped With SLIP-Like Articulated Legs Embodied in the Mechanical Design

Cited by 29 publications

References 28 publications

Using Elastically Actuated Legged Robots in Rough Terrain: Experiments with DLR Quadruped bert

Using Elastically Actuated Legged Robots in Rough Terrain: Experiments with DLR Quadruped bert

Adapting Highly-Dynamic Compliant Movements to Changing Environments: A Benchmark Comparison of Reflex- vs. CPG-Based Control Strategies

Limb dynamics in agility jumps of beginner and advanced dogs

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