Demands for pneumatic-driven soft robots are constantly rising for various applications. However, they are often designed manually due to the lack of systematic methods. Moreover, design-dependent characteristics of pneumatic actuation pose distinctive challenges. This paper provides a compact MATLAB code, named SoRoTop, and its various extensions for designing pneumatic-driven soft robots using topology optimization. The code uses the method of moving asymptotes as the optimizer and builds upon the approach initially presented in Kumar et al.(Struct Multidiscip Optim 61 (4): 1637-1655, 2020). The pneumatic load is modeled using Darcy's law with a conceptualized drainage term. Consistent nodal loads are determined from the resultant pressure field using the conventional finite element approach. The robust formulation is employed, i.e., the eroded and blueprint design descriptions are used. A min-max optimization problem is formulated using the output displacements of the eroded and blueprint designs. A volume constraint is imposed on the blueprint design, while the eroded design is used to apply a conceptualized strain energy constraint. The latter constraint aids in attaining optimized designs that can endure the applied load without compromising their performance. Sensitivities required for optimization are computed using the adjoint-variable method. The code is explained in detail, and various extensions are also presented. It is structured into pre-optimization, MMA optimization, and post-optimization operations, each of which is comprehensively detailed. The paper also illustrates the impact of load sensitivities on the optimized designs. SoRoTop is provided in Appendix A and is available with extensions in the supplementary material and publicly at \url{https://github.com/PrabhatIn/SoRoTop}.

翻译：气动驱动软体机器人在各类应用中的需求持续增长。然而，由于缺乏系统性设计方法，此类机器人通常依赖人工设计。此外，气动驱动的设计依赖特性带来了独特的挑战。本文提供了一个名为SoRoTop的紧凑型MATLAB代码及其扩展版本，用于通过拓扑优化设计气动驱动软体机器人。该代码采用移动渐近线法作为优化器，并基于Kumar等人（Struct Multidiscip Optim 61 (4): 1637-1655, 2020）提出的方法构建。气动载荷通过达西定律与概念化排水项建模，并采用传统有限元方法从所得压力场确定一致节点载荷。本文采用鲁棒公式化方法，即使用侵蚀设计与蓝图设计描述。通过输出侵蚀设计与蓝图设计的位移构建最小-最大优化问题，对蓝图设计施加体积约束，而对侵蚀设计应用概念化应变能约束。后者有助于获得能够承受施加载荷且不牺牲性能的优化设计。使用伴随变量法计算优化所需的灵敏度。本文详细阐述了代码结构及多种扩展方案，将操作划分为优化前、MMA优化与优化后三个阶段并逐一详述。同时展示了载荷灵敏度对优化设计的影响。SoRoTop代码见附录A，其扩展版本可在补充材料及开源平台\url{https://github.com/PrabhatIn/SoRoTop}获取。