Design and analysis of planar rotary springs

Georgiev, Nikola; Burdick, Joel W.

doi:10.1109/iros.2017.8206352

Cited by 13 publications

(3 citation statements)

References 12 publications

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“…Nevertheless, as functional patterns, they give us advantages beyond their beauty. A trace used in data storage [9], optimization algorithm [10], wearable thermoelectric generator [11], supramolecular chemical springs [12], stretchable electronics [13], soft actuators [14,15], antennas [16], metamaterials [17] and planar springs [18] are only a few examples of numerous engineering applications inspired by spirals.…”

Section: Introductionmentioning

confidence: 99%

Double-spiral: a bioinspired pre-programmable compliant joint with multiple degrees of freedom

Jafarpour

Gorb

Rajabi

2023

J. R. Soc. Interface.

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Geometry and material are two key factors that determine the functionality of mechanical elements under a specific boundary condition. Optimum combinations of these factors fulfil desired mechanical behaviour. By exploring biological systems, we find widespread spiral-shaped mechanical elements with various combinations of geometries and material properties functioning under different boundary conditions and load cases. Although these spirals work towards a wide range of goals, some of them are used as nature's solution to compactify highly extensible prolonged structures. Characterizing the principles underlying the functionality of these structures, here we profited from the coiling–uncoiling behaviour and easy adjustability of logarithmic spirals to design a pre-programmable compliant joint. Using the finite-element method, we developed a simple model of the joint and investigated the influence of design variables on its geometry and mechanical behaviour. Our results show that the design variables give us a great possibility to tune the response of the joint and reach a high level of passive control on its behaviour. Using 3D printing and mechanical testing, we replicated the numerical simulations and illustrated the application of the joint in practice. The simplicity, pre-programmability and predictable response of our double-spiral design suggest that it provides an efficient solution for a wide range of engineering applications, such as articulated robotic systems and modular metamaterials.

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Section: Introductionmentioning

confidence: 99%

Double-spiral: a bioinspired pre-programmable compliant joint with multiple degrees of freedom

Jafarpour

Gorb

Rajabi

2023

J. R. Soc. Interface.

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“…The latter concern may be responsible for the transition to monolithic springs in subsequent designs. One of the most common and successful planar monolith spring designs connects the central anchor to the rim with one or more spiral arms [14], [15], [16], [17], [18], [19]. This configuration is efficient and works well with a wide range of stiffness coefficients (e.g., 30-800 Nm/rad); however, the nature of the spiral arms often causes differences in stiffness depending on the direction of deflection [19].…”

mentioning

confidence: 99%

“…These designs have produced compact springs that are generally limited in their deflection (e.g., less than five degrees) and torque limits, which has diminished their success in some applications. While the overall spring performance has been well-predicted in some cases [17], [18], the directionality and limited range of motion are drawbacks of these approaches.…”

mentioning

confidence: 99%

An Energy-Dense Two-Part Torsion Spring Architecture and Design Tool

Bons,

Thomas,

Mooney

et al. 2024

IEEE/ASME Trans. Mechatron.

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Emerging wearable, assistive, and mobile robots seek to interact with the environment and/or humans in a compliant, dynamic, and adaptable way. Springs are critical to achieving this objective, but the associated increase in volume, mass, and complexity is limiting their application and impact in this rapidly developing field. This article presents a novel rotary spring architecture that is both lightweight and compact. Our two-part spring consists of radially-spaced cantilever beams that interface with an internal, gear-like camshaft. We present the concept and equations governing their mechanics and design. To facilitate broad adoption, we introduce an open-source design tool, which enables the design of custom springs in minutes instead of hours or days. We also empirically demonstrate our design with four test springs and validate the achievement of target spring rates and deflections. Finally, we present several redesigns of existing springs in the robotics literature to demonstrate the wide applicability of our spring architecture.

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