Soft robots could bring robotic systems to new horizons, by enabling safe human-machine interaction. For precise control, these soft structures require high level position feedback that is not easily achieved through conventional one-degree-of-freedom (DOF) sensing apparatus. In this paper, a soft two-DOF dielectric elastomer (DE) sensor is specifically designed to provide accurate position feedback for a soft polymer robotic manipulator. The technology is exemplified on a soft robot intended for MRI-guided prostate interventions. DEs are chosen for their major advantages of softness, high strains, low cost and embedded multiple-DOF sensing capability, providing excellent system integration. A geometrical model of the proposed DE sensor is developed and compared to experimental results in order to understand sensor mechanics. Using a differential measurement approach, a handmade prototype provided linear sensory behavior and 0.2 mm accuracy on two-DOF. This correlates to a 0.7\% error over the sensor's 30 mm x 30 mm planar range, demonstrating the outstanding potential of DE technology for accurate multi-DOF position sensing.

翻译：软体机器人有望将机器人系统推向新的高度，通过实现安全的人机交互。为实现精确控制，这些软体结构需要高水平的位置反馈，而传统的单自由度传感装置难以实现这一目标。本文专门设计了一种软二自由度介电弹性体传感器，用于为软聚合物机器人操作器提供精确的位置反馈。该技术以一款用于磁共振成像引导前列腺介入手术的软体机器人为例进行说明。选择介电弹性体是因其具有柔软性、高应变性、低成本和嵌入式多自由度传感能力等主要优势，可实现优异的系统集成。本文建立了所提出介电弹性体传感器的几何模型，并与实验结果进行比较，以理解传感器力学特性。采用差分测量方法，手工制作的原型在二自由度上实现了线性传感行为和0.2毫米的精度。这相当于在传感器30毫米×30毫米平面范围内0.7%的误差，证明了介电弹性体技术在精确多自由度位置传感方面的巨大潜力。