Orb-weaving spiders detect prey on a web using vibration sensors at leg joints. They often dynamically crouch their legs during prey sensing, likely an active sensing strategy. However, how leg crouching enhances sensing is poorly understood, because measuring system vibrations in behaving animals is difficult. We use robophysical modeling to study this problem. Our previous spider robot had only four legs, simplified leg morphology, and a shallow crouching range of motion. Here, we developed a new spider robot, with eight legs, each with four joints that better approximated spider leg morphology. Leg exoskeletons were 3-D printed and joint stiffness was tuned using integrated silicone molding with variable materials and geometry. Tendon-driven actuation allowed a motor in the body to crouch all eight legs deeply as spiders do, while accelerometers at leg joints record leg vibrations. Experiments showed that our new spider robot reproduced key vibration features observed in the previous robot while improving biological accuracy. Our new robot provides a biologically more accurate robophysical model for studying how leg behaviors modulate vibration sensing on a web.

翻译：圆网蜘蛛利用腿关节处的振动传感器探测网上的猎物。在感知猎物时，它们常动态蜷缩腿部，这很可能是一种主动感知策略。然而，由于在行为动物中测量系统振动较为困难，腿部蜷缩如何增强感知能力尚不明确。我们采用机器人物理建模研究此问题。先前的蜘蛛机器人仅有四条腿，腿部形态简化，且蜷缩运动范围较浅。本文开发了一种新型蜘蛛机器人，具有八条腿，每条腿包含四个关节，更接近蜘蛛腿部形态。腿部外骨骼通过3D打印制造，关节刚度则通过集成硅胶模塑技术，采用不同材料与几何形状进行调节。肌腱驱动机构使体内单个电机能如真实蜘蛛般深度蜷缩所有八条腿，同时腿关节处的加速度计记录腿部振动。实验表明，新型蜘蛛机器人在提升生物精确度的同时，复现了先前机器人观测到的关键振动特征。本新型机器人为研究腿部行为如何调节网上振动感知提供了生物精确度更高的机器人物理模型。