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Sensing and actuation are intricately connected in soft robotics, where contact may change actuator mechanics and robot behavior. To improve soft robotic control and performance, proprioception and contact sensors are needed to report robot state without altering actuation mechanics or introducing bulky, rigid components. For bioinspired McKibben-style fluidic actuators, prior work in sensing has focused on sensing the strain of the actuator by embedding sensors in the actuator bladder during fabrication, or by adhering sensors to the actuator surface after fabrication. However, material property mismatches between sensors and actuators can impede actuator performance, and many soft sensors available for use with fluidic actuators rely on costly or labor-intensive fabrication methods. Here, we demonstrate a low-cost and easy-to manufacture-tubular liquid metal strain sensor for use with soft actuators that can be used to detect actuator strain and contact between the actuator and external objects. The sensor is flexible, can be fabricated with commercial-off-the-shelf components, and can be easily integrated with existing soft actuators to supplement sensing, regardless of actuator shape or size. Furthermore, the soft tubular strain sensor exhibits low hysteresis and high sensitivity. The approach presented in this work provides a low-cost, soft sensing solution for broad application in soft robotics.
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Design of a Simple and Rugged Soft Polydimethylsiloxane‐Carbon Nanotube‐Graphene‐Based Composite Sensor
Abstract Many applications in human health screening, soft robotics, and structural health monitoring require sensors that can accommodate large deformations and highly curved geometries, while providing reliable measurements across a range of frequencies. Ideally, such sensors will also be low cost and easy to manufacture. While prior studies achieve some of these goals, it is rare to achieve them all in a holistic manner. Here, a soft sensor that is easy to manufacture, affordable, and water compatible is presented. The sensor is made of a combination of carbon nanotubes and few‐layer graphene dispersed in a polydimethylsiloxane elastomer. The sensor's ability to detect a broad range of frequencies under both uniaxial stretch and bending is demonstrated. The sensor is effective in multiple configurations, including directly stretching the sensor, adhering the sensor to a deforming compliant substrate, and operating under water. Specifically, the sensor can accurately detect vibrational frequencies with amplitudes as small as 0.1% strain and excitation frequencies covering a broad range of 50–600 Hz with an average root mean square error (RMSE) of 0.16%. Even in the presence of large (≈ 20%) deformations and aqueous environments the sensor can recover the fundamental and higher order vibrational modes within less than 2% error.
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- Award ID(s):
- 2200353
- PAR ID:
- 10640961
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 10
- Issue:
- 16
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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