Soft robots have morphological characteristics that make them preferred candidates, over their traditionally rigid counterparts, for executing physical interaction tasks with the environment. Therefore, equipping them with force sensing is essential for ensuring safety, enhancing their controllability, and adding autonomy. At the same time, it is necessary to preserve their inherent flexibility when integrating sensory units. Soft-fluidic actuators (SFAs) with hydraulic actuation address some of the challenges posed by the compressibility of pneumatic actuation while maintaining system compliance. This research further investigates the feasibility of utilizing the incompressible actuation fluid as the means of actuation and of multiaxial sensing. We have developed a hyperelastic model for the actuation pressure, acting as a baseline pressure. Any disparities from the baseline have been mapped to external forces, using the principle of pressure-based fluidic soft sensor. Computed tomography imaging has been used to examine inner deformation and validate the analytically derived actuation-pressure model. The induced stresses within the SFA are examined using COMSOL simulations, contributing to the development of a calibration algorithm, which accounts for geometric and cross-sectional nonlinearities and maps pressure variations with tip forces. Two force types (concentrated and distributed) acting on our SFA under different configurations are examined, using two experimental setups described as "Point Load" and "Distributed Force." The force sensing algorithm achieves high accuracy with a maximum absolute error of 0.32N for forces with a magnitude of up to 6N.

中文翻译：

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流体多腔致动器和多轴固有力传感。


软体机器人具有形态学特征，与传统的刚性机器人相比，它们成为执行与环境的物理交互任务的首选人选。因此，为它们配备力传感对于确保安全、增强其可控性和增加自主性至关重要。同时，在整合感觉单元时，有必要保持它们固有的灵活性。具有液压驱动的软流体执行器 （SFA） 解决了气动驱动可压缩性带来的一些挑战，同时保持了系统合规性。本研究进一步调查了利用不可压缩驱动液作为驱动和多轴传感手段的可行性。我们开发了一个用于驱动压力的超弹性模型，用作基线压力。使用基于压力的流体软传感器的原理，与基线的任何差异都已映射到外力。计算机断层扫描成像已用于检查内部变形并验证分析得出的驱动压力模型。使用 COMSOL 仿真检查 SFA 内的感应应力，有助于开发校准算法，该算法考虑了几何和横截面非线性，并映射了压力变化与尖端力的关系。使用两种实验设置（称为“点载荷”和“分布式力”），研究了在不同配置下作用在 SFA 上的两种力类型（集中和分布式）。力传感算法可实现高精度，对于高达 6N 的力，最大绝对误差为 0.32N。