Soft pneumatic actuators (SPAs) are widely employed to drive soft robots. However, their inherent flexibility offers both benefits and challenges. This property reduces their output force/torque and makes them hard to control. This paper introduces a new design method that enhances the actuator's performance and controllability. The complex structure of the soft actuator is simplified by approximating it as a cantilever beam. This allows us to derive a mechanical equation between input pressure to output torque. Additionally, a dynamical model is explored to understand the correlation between the natural frequency and dimensional parameters of the SPA. The design problem is then transformed into an optimization problem, using the mechanical equation as the objective function and the dynamical equation as a constraint. By solving this optimization problem, the optimal dimensional parameters are determined. Prior to fabrication, preliminary tests are conducted using the finite element method. Six prototypes are manufactured to validate the proposed approach. The optimal actuator successfully generates the desired force/torque, while its natural frequency remains within the constrained range. This work highlights the potential of using approximated models and optimization formulation to boost the efficiency and dynamic performance of soft pneumatic actuators.

翻译：软体气动执行器（SPAs）广泛应用于驱动软体机器人。然而，其固有的柔顺性既带来优势也带来挑战：该特性不仅降低了执行器的输出力/力矩，还增加了控制难度。本文提出了一种新型设计方法，可同时增强执行器的性能与可控性。通过将软体执行器的复杂结构简化为悬臂梁模型，推导出输入气压与输出力矩之间的力学方程。进一步建立动力学模型，揭示SPA固有频率与尺寸参数的相关性。随后将设计问题转化为优化问题，以力学方程为目标函数、动力学方程为约束条件，通过求解优化问题确定最优尺寸参数。在制造前采用有限元法进行初步测试，并制造了六个原型样机验证所提方法。优化后的执行器成功产生所需力/力矩，同时其固有频率保持在约束范围内。本研究揭示了利用近似模型与优化公式提升软体气动执行器效率与动态性能的潜力。