气动软体致动器在工程领域具有广阔的应用前景，以前主要采用梁、杆等简单模型对其进行整体变形研究，与刚性材料的硬接触不同，如何对软体致动器的软接触建立准确的力学模型并对其整体构型和应力分布进行分析仍是个具有挑战性的难题.本研究针对多腔体气动软体致动器相邻两气腔之间的软接触问题，提出了一种新的建模方法.本力学模型综合考虑气腔结构的复杂性、几何非线性和材料非线性，采用多点接触的面-面接触方法，解决了不考虑接触时相邻两气腔之间的相互穿透问题，适用于大变形柔软体结构的分析.与传统的梁、杆等模型相比，本模型既提高了模拟整体变形的精度，又能够准确描述气腔结构内部的应力分布规律.对多腔体气动软体致动器的仿真结果表明，相邻两气腔之间的软接触对其大变形影响显著.最后，对软体四爪机构抓取圆柱体的整个过程进行了准静态研究，详细阐述了整体构型变化和Mises应力分布情况，结果显示接触区域应力达到最大值.本研究对软体致动器的力学特性分析和优化设计具有一定的理论指导意义.
Pneumatic soft actuators have broad application prospects in engineering fields. The whole deformation investigation on soft actuators used to be carried out mainly by adopting simple models such as beams and rods, which is different from hard contact of rigid materials. Therefore, the establishment of accurate mechanical models and analysis of the overall configuration and stress distribution for soft contact of soft actuators are still challenging conundrums. Aimed at the soft contact problem between two adjacent air chambers of a pneumatic soft actuator with multiple chambers, a novel modeling approach is proposed in this paper by combining the complexity of the air chamber structure with geometric and material nonlinearities, and employing the segment-to-segment contact method for multiple-point contact. It has solved the interpenetration problem between two adjacent air chambers without considering the contact interaction, which is suitable for analyzing soft structures with large deformation. Compared with traditional models like beams and rods, this model can not only improve the accuracy in simulating the overall deformation, but also accurately describe the stress distribution law inside the air chamber structure. The simulation results for the pneumatic soft actuator with multiple chambers demonstrate that the soft contact between adjacent air chambers has a remarkable effect on large deflection of the actuator. Finally, the quasi-static research on the whole process of grasping a cylinder by a soft four-claw mechanism is implemented, and the overall configuration variations and Mises stress distribution are elaborated in detail. The results show that the stress in the contact area reaches a maximum value. This paper is of theoretical guiding significance for the mechanical property analysis and optimal design of soft actuators.
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