Recently, in the search for alternatives to conventional robots, various types of soft actuators and their applications have been studied. In particular, pneumatic soft actuators have the advantage of being lightweight and high power. One of the uses of these soft actuators is as a substitute for an electric motor to actuate the joint of a structure, such as a link mechanism. Another use involves their fusion with a flexible structure. The features of this concept are a simplified system, in which almost all interfaces can be configured as flexible structures. However, because these actuatable flexible structures are made with rubber, silicone, or flexible resin, it is difficult for them to support their own weight owing to the effect of the square-cube law in the case of increasing size. Hence, these structures are limited to a size of approximately $1 \times 10^{-2}-1 \times 10^{-1} \mathrm{m}$. If an actuatable flexible structure with a size of $1 \times 10^{0}$ m can be realized, the concept of soft actuator–flexible structure fusion is expected to provide novel solutions and applications. Herein, as a feasibility study, large actuatable flexible structures were developed. The proposed structure, LayerCAKE, is a laminated open-cell and closed-cell foam structure; cell foam is a lightweight and flexible material that can be used to realize large actuatable flexible structures. LayerCAKE is actuated by using the concept that open- and closed-cell foams contract differently when they are vacuumed. The bending-motion model and was experimentally verified, and different types of LayerCAKE models that could exhibit various types of motion were developed and tested. Furthermore, a complex-shaped LayerCAKE model (in the shape of a human hand) was developed. A large actuatable flexible structure of approximately 900 mm was realized. Furthermore, it was confirmed that the bending motion could be controlled by pressure.
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Laminated foam-based soft actuator for actuatable flexible structure
Semantic Scholar · Engineering · 2019
Abstract
Recently, in the search for alternatives to conventional robots, various types of soft actuators and their applications have been studied. In particular, pneumatic soft actuators have the advantage of being lightweight and high power. One of the uses of these soft actuators is as a substitute for an electric motor to actuate the joint of a structure, such as a link mechanism. Another use involves their fusion with a flexible structure. The features of this concept are a simplified system, in which almost all interfaces can be configured as flexible structures. However, because these actuatable flexible structures are made with rubber, silicone, or flexible resin, it is difficult for them to support their own weight owing to the effect of the square-cube law in the case of increasing size. Hence, these structures are limited to a size of approximately $1 \times 10^{-2}-1 \times 10^{-1} \mathrm{m}$. If an actuatable flexible structure with a size of $1 \times 10^{0}$ m can be realized, the concept of soft actuator–flexible structure fusion is expected to provide novel solutions and applications. Herein, as a feasibility study, large actuatable flexible structures were developed. The proposed structure, LayerCAKE, is a laminated open-cell and closed-cell foam structure; cell foam is a lightweight and flexible material that can be used to realize large actuatable flexible structures. LayerCAKE is actuated by using the concept that open- and closed-cell foams contract differently when they are vacuumed. The bending-motion model and was experimentally verified, and different types of LayerCAKE models that could exhibit various types of motion were developed and tested. Furthermore, a complex-shaped LayerCAKE model (in the shape of a human hand) was developed. A large actuatable flexible structure of approximately 900 mm was realized. Furthermore, it was confirmed that the bending motion could be controlled by pressure.