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. 2021 Aug 11:8:632835.
doi: 10.3389/frobt.2021.632835. eCollection 2021.

Performance Metrics for Fluidic Soft Robot Rotational Actuators

Levi Rupert  1 , Benjamin O Saunders  1 , Marc D Killpack  1
Affiliations

Performance Metrics for Fluidic Soft Robot Rotational Actuators

Levi Rupert et al. Front Robot AI. .

Abstract

The field of soft robotics is continuing to grow as more researchers see the potential for robots that can safely interact in unmodeled, unstructured, and uncertain environments. However, in order for the design, integration, and control of soft robotic actuators to develop into a full engineering methodology, a set of metrics and standards need to be established. This paper attempts to lay the groundwork for that process by proposing six soft robot actuator metrics that can be used to evaluate and compare characteristics and performance of soft robot actuators. Data from eight different soft robot rotational actuators (five distinct designs) were used to evaluate these soft robot actuator metrics and show their utility. Additionally we provide a simple case study as an example of how these metrics can be used to evaluate soft robot actuators for a designated task. While this paper does not claim to present a comprehensive list of all possible soft robot actuator metrics, the metrics presented can 1) be used to initiate the development and comparison of soft robot actuators in an engineering framework and 2) start a broader discussion of which metrics should be standardized in future soft robot actuator research.

Keywords: benchmarking; evaluation; fluidic actuators; performance; soft robot metrics; soft robotics.

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Conflict of interest statement

Author LR was employed by company Otherlab Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Large soft robot actuators used in this work. The highlighted sections in red are the sections used in the mass and Torque-to-Mass Ratio metrics. (A) Blow-molded Continuum actuator (B) Bead Continuum actuator (C) Rubberized Rotary Elastic Chamber actuator (D) Fabric Rotary Elastic Chamber actuator
FIGURE 2
FIGURE 2
Fluidic Elastic Actuators used in this work from left to right: Large TPU, Medium TPU, Small TPU, and Small NinjaFlex.
FIGURE 3
FIGURE 3
Plot of the metric values for the scaled TPU Fluidic Elastic Actuators divided by the metric values of the Small TPU Fluidic Elastic Actuator. The non-linear nature of most of the metrics means that there is not a one to one mapping between scaling and what the resultant metric will be.
FIGURE 4
FIGURE 4
Bar plot of the Torque-to-Mass Ratios.
FIGURE 5
FIGURE 5
Relationship between energy and torque for the antagonistic actuators.
FIGURE 6
FIGURE 6
Relationship between energy and torque for the fluidic elastic actuators (FlEA). As the size of the actuator increases the amount of efficiency of the actuator decreased.
FIGURE 7
FIGURE 7
The variable stiffness relationship between pressure and stiffness for the antagonistic actuators.
See this image and copyright information in PMC

References

    1. Agarwal G., Besuchet N., Audergon B., Paik J. (2016). Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices. Sci. Rep. 6, 34224. 10.1038/srep34224 - DOI - PMC - PubMed
    1. Albu-Schäffer A., Bicchi A. (2016). “Actuators for Soft Robotics,” in Springer Handbood of Robotics. Editors Siciliano B., Khatib O. (Cham: Springer; ), 499–530. 10.1007/978-3-319-32552-1_21 - DOI
    1. Best C. M., Gillespie M. T., Hyatt P., Rupert L., Sherrod V., Killpack M. D. (2016). A New Soft Robot Control Method: Using Model Predictive Control for a Pneumatically Actuated Humanoid. IEEE Robot. Automat. Mag. 23, 75–84. 10.1109/mra.2016.2580591 - DOI
    1. Best C. M., Rupert L., Killpack M. D. (2020). Comparing Model-Based Control Methods for Simultaneous Stiffness and Position Control of Inflatable Soft Robots. Int. J. Robotics Res. 40, 0278364920911960. 10.1177/0278364920911960 - DOI
    1. Bodily D. M., Allen T. F., Killpack M. D. (2017). Multi-objective Design Optimization of a Soft, Pneumatic Robot. In 2017 IEEE International Conference on Robotics and Automation (ICRA). IEEE, 1864–1871. 10.1109/icra.2017.7989218 - DOI

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