A Review of Research on Falling Cat Phenomenon and Development of Bio-Falling Cat Robot

Cao, Jian; Wang, Shanbo; Zhu, Xiaocong; Song, Lei

doi:10.1109/wrcsara57040.2022.9903971

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…It so happens that this flywheel design follows the mechanics of a falling cat, which re-orients itself during its fall in order to land on its feet. Among the different models of a falling cat proposed by the literature [8][9][10][11], Rademaker [9] considers a falling cat as two rolling cylinders that keep a constant relative bending angle (Figure 13). Each cylinder has its own oblique and constant angular momentum (L ′ 1 and L ′ 2 ), resulting in a non-zero total angular momentum in the same manner as the proposed mechanism.…”

Section: Analogy With a Falling Catmentioning

confidence: 99%

Design of a Flexure-Based Flywheel for the Storage of Angular Momentum and Kinetic Energy

Flückiger,

Cosandier,

Schneegans

et al. 2024

Machines

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The flywheel is a widespread mechanical component used for the storage of kinetic energy and angular momentum. It typically consists of cylindrical inertia rotating about its axis on rolling bearings, which involves undesired friction, lubrication, and wear. This paper presents an alternative mechanism that is functionally equivalent to a classical flywheel while relying exclusively on limited-stroke flexure joints. This novel one-degree-of-freedom zero-force mechanism has no wear and requires no lubrication: it is thus compatible with extreme environments, such as vacuum, cryogenics, or ionizing radiation. The mechanism is composed of two coupled pivoting rigid bodies whose individual angular momenta vary during motion but whose sum is constant at all times when the pivoting rate is constant. The quantitative comparison of the flexure-based flywheel to classical ones based on a hollow cylinder as inertia shows that the former typically stores 6 times less angular momentum and kinetic energy for the same mass while typically occupying 10 times more volume. The freedom of design of the shape of the rigid bodies offers the possibility of modifying the ratio of the stored kinetic energy versus angular momentum, which is not possible with classical flywheels. For example, a flexure-based flywheel with rigid pivoting bodies in the shape of thin discs stores 100 times more kinetic energy than a classical flywheel with the same angular momentum. A proof-of-concept prototype was successfully built and characterized in terms of reaction moment generation, which validates the presented analytical model.

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Section: Analogy With a Falling Catmentioning

confidence: 99%

Design of a Flexure-Based Flywheel for the Storage of Angular Momentum and Kinetic Energy

Flückiger,

Cosandier,

Schneegans

et al. 2024

Machines

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“…Models for robot terrestrial self-righting have considered the transitions between mechanically stable and unstable configurations, potential energy landscapes, and the motions required for the body and legs to coordinate overturning (Peng et al, 2017). In a different context, robot designs inspired by the self-righting abilities of falling cats dynamically reconfigure rotational inertia (inertial morphing) so as to perform rotational reorientations at zero external torque (Cao et al, 2022; Shield et al, 2021). Although this mechanism has also been applied to self-righting robot design (Wang et al, 2022), we are not aware of any studies of animals taking advantage of poses and motions that minimize rotational inertia and hence the torque required to flip upright during terrestrial self-righting (Casarez, 2018).…”

Section: Introductionmentioning

confidence: 99%

Using pose estimation and 3D rendered models to study leg-mediated self-righting by lanternflies

Bien

Alexander

et al. 2023

Preprint

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The ability to upright quickly and efficiently when overturned on the ground (terrestrial self-righting) is crucial for living organisms and robots. The emerging field of terradynamics seeks to understand how and why different animals use diverse self-righting strategies. We studied this behavior using high speed multiangle video in nymphs of the invasive spotted lanternfly (SLF, Lycorma delicatula), an insect that must frequently recover from falling in its native habitat. While most insect species previously studied can use wing opening to facilitate overturning, nymphs, like most robots, are wingless. SLFs were highly successful at self-righting (>92% of trials) with no significant difference in the time or number of attempts required for three substrates with varying friction and roughness. These nymphs seldom overturned using the pitching and rolling strategies observed for other insect species, instead primarily flipping upright by rotating around a diagonal body axis. To understand these motions, we used video, photogrammetry and Blender rendering software to create novel, highly realistic 3D models of SLF body poses during each strategy. These models were analyzed using the energy landscape theory of self-righting, which posits that animals use methods that minimize energy barriers to overturning, and inertial morphing, which proposes the animal adjusts its body pose to minimize the rotational inertia during overturning, a theory which has not been applied to self-righting. A combination of both theories was found to explain the observed preferred strategies of this species, indicating the value of using 3D renderings with mechanical modeling for terradynamics and biomimetic applications.

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A Review of Research on Falling Cat Phenomenon and Development of Bio-Falling Cat Robot

Cited by 2 publications

References 16 publications

Design of a Flexure-Based Flywheel for the Storage of Angular Momentum and Kinetic Energy

Design of a Flexure-Based Flywheel for the Storage of Angular Momentum and Kinetic Energy

Using pose estimation and 3D rendered models to study leg-mediated self-righting by lanternflies

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