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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由智能水凝胶驱动的可变刚度软夹持器的基于模型的设计。


软抓手已显示出它们能够抓取易碎和形状不规则的物体，但它们通常需要外部机构进行驱动，从而限制了它们在大规模情况下的使用。它们处理载荷和变形的能力有限，这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持器。建议的致动器包括一个硅胶室，该硅胶室带有包含水凝胶球体的独立单元。这些球体表现出温度触发的膨胀和收缩行为。此外，嵌入在单元中的可变刚度条作为刚度变化法引入。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行为并探索对弯曲性能的影响因素。结果表明，可以对促动器进行编程以以所需的方式响应，并且刚度变化方法显著提高了弯曲刚度。具体来说，弯曲角和水凝胶球层之间存在直接关联，最大达到 128°。此外，将间隙配置纳入腔室膜可使弯曲角度最多增加三倍。此外，膜类型对 21.3° 至 24.6° 的弯曲角度的影响最小。此外，嵌入的可变刚度条大大提高了刚度，从而使弯曲刚度提高了 30 倍。总之，新型软抓手致动器通过主动驱动实现大量的弯曲和刚度控制，展示了在复杂和多尺度抓握场景中提高软抓手性能的潜力。