A Bioinspired Stress‐Response Strategy for High‐Speed Soft Grippers

Lin, Yangqiao; Zhang, Chao; Wei, Tang; Zhang, Jiao; Wang, JinRong; Wang, Wei; Zhong, Yuhan; Zhu, Pingan; Hu, Yi; Yang, Huayong; Zou, Jun

doi:10.1002/advs.202102539

Cited by 40 publications

(27 citation statements)

References 24 publications

(22 reference statements)

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“…In addition to fast locomotion, we also demonstrated its application in designing soft grippers with tunable stiffness to grasping a variety of objects ranging from fragile lightweight to high-load objects. Very recently, similar bistable linkage-spring mechanism-based soft gripper was reported with demonstrated high-speed and multimode grasping, [232] where the pre-tensioned spring is replaced by rubber band.…”

Section: Linkages With Springs or Soft Jointsmentioning

confidence: 85%

Bistable and Multistable Actuators for Soft Robots: Structures, Materials, and Functionalities

et al. 2022

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Snap‐through bistability is often observed in nature (e.g., fast snapping to closure of Venus flytrap) and the life (e.g., bottle caps and hair clippers). Recently, harnessing bistability and multistability in different structures and soft materials has attracted growing interest for high‐performance soft actuators and soft robots. They have demonstrated broad and unique applications in high‐speed locomotion on land and under water, adaptive sensing and fast grasping, shape reconfiguration, electronics‐free controls with a single input, and logic computation. Here, an overview of integrating bistable and multistable structures with soft actuating materials for diverse soft actuators and soft/flexible robots is given. The mechanics‐guided structural design principles for five categories of basic bistable elements from 1D to 3D (i.e., constrained beams, curved plates, dome shells, compliant mechanisms of linkages with flexible hinges and deformable origami, and balloon structures) are first presented, alongside brief discussions of typical soft actuating materials (i.e., fluidic elastomers and stimuli‐responsive materials such as electro‐, photo‐, thermo‐, magnetic‐, and hydro‐responsive polymers). Following that, integrating these soft materials with each category of bistable elements for soft bistable and multistable actuators and their diverse robotic applications are discussed. To conclude, perspectives on the challenges and opportunities in this emerging field are considered.

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Section: Linkages With Springs or Soft Jointsmentioning

confidence: 85%

Bistable and Multistable Actuators for Soft Robots: Structures, Materials, and Functionalities

et al. 2022

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“…When the external environment changes, the microactuator will undergo a change from a higher to a lower state of elastic energy and will release the elastic energy as kinetic energy. [49] Therefore, it is possible to modulate the release behavior by regulating the duration of the stimuli responsive process. As shown in Figure 6b; and Movie 2 (Supporting Information), if the acidic solution is completely removed from the environment and an alkaline solution (pH = 13) is immediately added, the rapid change in the solution environment will cause the elastic potential energy accumulated by the microactuator to be released in a short period of time.…”

Section: Wwwadvmattechnoldementioning

confidence: 99%

Flytrap Inspired pH‐Driven 3D Hydrogel Actuator by Femtosecond Laser Microfabrication

Wang

Jin

Dong

et al. 2022

Adv Materials Technologies

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With the development of bionics and nanophotonics, hydrogel microactuators capable of responding to external stimuli to produce controllable deformations have attracted a great deal of interest. These microactuators hold significant promise in areas such as bionic devices, soft robotics, and precision sensors. It is not a trivial task to make such small devices as well as to make them work in a controlled manner. Here, inspired by the intelligent response of flytrap, a smart hydrogel microactuator based on a bionic asymmetric structure is demonstrated. The designed asymmetric microstructure is fabricated by femtosecond laser direct writing with deformation time of 1.2 s and recovery time of 0.3 s. The grasping and releasing behavior of the microactuator for micro‐objects can be realized and tuned by using pH‐triggered shape changes, demonstrating its potential for applications, such as flexible robotics, smart sensors, and microscopic manipulation.

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“…These inherent features of bistable structures render them a promising strategy for their use in soft actuators. With a rational design, a variety of actuators and robotics with snap-through instability have been explored to achieve large deformations, and stimuli-responsive materials have been integrated with the bistable structures to provide moderate actuation forces [ 33 , 54 , 62 , 63 , 64 ]. Controllable snap-through actuation occurs when a suitable stimulus offers the trigger force to sufficiently overcome the energy barrier between different stable states, as shown in Figure 8 a.…”

Section: Structural Instabilitymentioning

confidence: 99%

“…Inspired by the prey-trapping strategy of the Venus flytrap, Lin et al designed a high-speed soft gripper using snap-through instability to achieve a fast response to external stimuli. The pneumatic control method was adopted to make the trigger process repeatable, which can also actively control the trigger sensitivity [ 64 ].…”

Section: Structural Instabilitymentioning

confidence: 99%

Programming Soft Shape-Morphing Systems by Harnessing Strain Mismatch and Snap-Through Bistability: A Review

Guo

Wei

et al. 2022

Materials

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Multi-modal and controllable shape-morphing constitutes the cornerstone of the functionalization of soft actuators/robots. Involving heterogeneity through material layout is a widely used strategy to generate internal mismatches in active morphing structures. Once triggered by external stimuli, the entire structure undergoes cooperative deformation by minimizing the potential energy. However, the intrinsic limitation of soft materials emerges when it comes to applications such as soft actuators or load-bearing structures that require fast response and large output force. Many researchers have explored the use of the structural principle of snap-through bistability as the morphing mechanisms. Bistable or multi-stable mechanical systems possess more than one local energy minimum and are capable of resting in any of these equilibrium states without external forces. The snap-through motion could overcome energy barriers to switch among these stable or metastable states with dramatically distinct geometries. Attributed to the energy storage and release mechanism, such snap-through transition is quite highly efficient, accompanied by fast response speed, large displacement magnitude, high manipulation strength, and moderate driving force. For example, the shape-morphing timescale of conventional hydrogel systems is usually tens of minutes, while the activation time of hydrogel actuators using the elastic snapping instability strategy can be reduced to below 1 s. By rationally embedding stimuli-responsive inclusions to offer the required trigger energy, various controllable snap-through actuations could be achieved. This review summarizes the current shape-morphing programming strategies based on mismatch strain induced by material heterogeneity, with emphasis on how to leverage snap-through bistability to broaden the applications of the shape-morphing structures in soft robotics and mechanical metamaterials.

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A Bioinspired Stress‐Response Strategy for High‐Speed Soft Grippers

Cited by 40 publications

References 24 publications

Bistable and Multistable Actuators for Soft Robots: Structures, Materials, and Functionalities

Bistable and Multistable Actuators for Soft Robots: Structures, Materials, and Functionalities

Flytrap Inspired pH‐Driven 3D Hydrogel Actuator by Femtosecond Laser Microfabrication

Programming Soft Shape-Morphing Systems by Harnessing Strain Mismatch and Snap-Through Bistability: A Review

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