Soft grippers have shown their ability to grasp fragile and irregularly shaped objects, but they often require external mechanisms for actuation, limiting their use in large-scale situations. Their limited capacity to handle loads and deformations also restricts their customized grasping capabilities. To address these issues, a model-based soft gripper with adaptable stiffness was proposed. The proposed actuator comprises a silicone chamber with separate units containing hydrogel spheres. These spheres exhibit temperature-triggered swelling and shrinking behaviors. In addition, variable stiffness strips embedded in the units are introduced as the stiffness variation method. The validated finite element method model was used as the model-based design approach to describe the hydrogel behaviors and explore the affected factors on the bending performance. The results demonstrate that the actuator can be programmed to respond in a desired way, and the stiffness variation method enhances bending stiffness significantly. Specifically, a direct correlation exists between the bending angle and hydrogel sphere layers, with a maximum of 128° achieved. In addition, incorporating gap configurations into the chamber membrane results in a maximum threefold increase in the bending angle. Besides, the membrane type minimally impacts the bending angle from 21.3° to 24.6°. In addition, the embedded variable stiffness strips substantially increase stiffness, resulting in a 30-fold rise in bending stiffness. In conclusion, the novel soft gripper actuator enables substantial bending and stiffness control through active actuation, showcasing the potential for enhancing soft gripper performance in complex and multiscale grasping scenarios.

中文翻译：

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智能水凝胶驱动的可变刚度软夹具的基于模型的设计。


软夹具已显示出其抓取易碎和不规则形状物体的能力，但它们通常需要外部机制来驱动，限制了它们在大规模情况下的使用。它们处理负载和变形的能力有限也限制了它们的定制抓取能力。为了解决这些问题，提出了一种具有自适应刚度的基于模型的软夹具。所提出的致动器包括一个硅树脂室，该室具有包含水凝胶球的单独单元。这些球体表现出温度引发的膨胀和收缩行为。此外，引入了嵌入单元中的可变刚度条作为刚度变化方法。使用经过验证的有限元方法模型作为基于模型的设计方法来描述水凝胶的行为并探索对弯曲性能的影响因素。结果表明，执行器可以通过编程以所需的方式响应，并且刚度变化方法显着增强了弯曲刚度。具体来说，弯曲角度和水凝胶球层之间存在直接相关性，最大可达 128°。此外，将间隙配置合并到室膜中可以使弯曲角度最大增加三倍。此外，膜类型对21.3°至24.6°弯曲角度的影响最小。此外，嵌入的可变刚度条大幅提高了刚度，使弯曲刚度提高了 30 倍。总之，新型软夹具执行器可以通过主动驱动实现大幅弯曲和刚度控制，展示了在复杂和多尺度抓取场景中增强软夹具性能的潜力。