Matching the rich multimodality of natural organisms, i.e., the ability to transition between crawling and swimming, walking and jumping, etc., represents a grand challenge in the fields of soft and bio‐inspired robotics. Here, a multimodal soft robot locomotion using highly compact and dynamic bistable soft actuators is achieved. These actuators are composed of a prestretched membrane sandwiched between two 3D printed frames with embedded shape memory alloy (SMA) coils. The actuator can swiftly transform between two oppositely curved states and generate a force of 0.3 N through a snap‐through instability that is triggered after 0.2 s of electrical activation with an input power of 21.1 ± 0.32
Soft robots composed of elastic materials can exhibit nonlinear behaviors, such as variable stiffness and adaptable deformation, that are favorable to cooperation with humans. These characteristics enable soft robots to be used in multiple applications, ranging from minimally invasive surgery and search and rescue in emergency or hazardous environments to marine or space exploration and assistive devices for people with musculoskeletal disorders. Although soft actuators composed of smart materials have been proposed as a control strategy for soft robots, most studies have focused on traditional actuators using hydraulic or pneumatic pressure. Over the years, these have made a lot of progress, but they have not been able to overcome the limitations of the complex configuration of the system and the expansion of the cross-section of the actuator when contracted. This paper merges the actuator design methodology for smart materials with the mechanical analysis of auxetic structures to present an electrically driven soft actuator architecture that achieves reliable actuation displacements. This novel soft actuator, constructed with contractile SMA springs and flexible auxetic metamaterials (FAM), has a spontaneous recovery of the shape after a contraction, a negative Poisson’s ratio, and over 90% of consistency with the performance predictions at the design stage. Our research presents a methodology for the design of a new electrically driven soft actuator, describes the manufacture of SMA springs and FAM, and concludes with the validation of the design by experimental analysis using the 2D planar soft actuator prototype. Finally, our study revealed that the application of the extraordinary characteristics of smart materials and structures together into a single architecture can be a strategy to overcome the limitations of existing soft actuator studies.
more » « less- Award ID(s):
- 1943715
- PAR ID:
- 10477221
- Publisher / Repository:
- American Society of Mechanical Engineers
- Date Published:
- ISBN:
- 978-0-7918-8752-3
- Format(s):
- Medium: X
- Location:
- Austin, Texas, USA
- Sponsoring Org:
- National Science Foundation
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Abstract W (i.e., electrical energy input of 4.22 ± 0.06J . The consistency and robustness of the snap‐through actuator response is experimentally validated through cyclical testing (580 cycles). The compact and fast‐responding properties of the soft bistable actuator allow it to be used as an artificial muscle for shape‐reconfigurable soft robots capable of multiple modes of SMA‐powered locomotion. This is demonstrated by creating three soft robots, including a reconfigurable amphibious robot that can walk on land and swim in water, a jumping robot (multimodal crawler) that can crawl and jump, and a caterpillar‐inspired rolling robot that can crawl and roll. -
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1115/SMASIS2023-111012
