This study proposes a low-cost coil-shaped optical fiber (COF) sensor that can be used in the twisted and coiled polymer fiber (TCPF) actuator unit. The TCPF is a thermal-driven artificial muscle with large stroke and large power ratio. To improve its response, several actuator units, which combine the TCPF with a cooling system, were developed. However, the displacement sensors for these units were not established, unlike the encoder for the motor. Although several methods are available to estimate the TCPF displacement, they are based on the resistance of the heating wire and are affected by TCPF actuation and load change. Therefore, to accurately measure displacement, in this study, we focus on the bending loss of optical fiber, which is often used in soft robotics. Because the bending loss of COFs is caused by the change in length of the coil, the displacement can be obtained by measuring the light intensity through the optical fiber. This study experimentally demonstrates that the COF is available, even when driving the TCPF actuator and changing the load.

中文翻译：

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用于扭曲和卷绕聚合物光纤执行器单元的低成本线圈形光纤位移传感器


这项研究提出了一种低成本的线圈形光纤（COF）传感器，可用于扭曲和线圈聚合物纤维（TCPF）执行器单元。 TCPF是一种大行程、大功率比的热驱动人造肌肉。为了提高其响应，开发了多个将 TCPF 与冷却系统相结合的执行器单元。然而，与电机的编码器不同，这些单元的位移传感器尚未建立。尽管有多种方法可用于估计 TCPF 位移，但它们都是基于电热丝的电阻，并受到 TCPF 驱动和负载变化的影响。因此，为了准确测量位移，在本研究中，我们重点研究软体机器人中经常使用的光纤的弯曲损耗。由于COF的弯曲损耗是由线圈长度的变化引起的，因此可以通过测量通过光纤的光强度来获得位移。这项研究通过实验证明，即使在驱动 TCPF 执行器并改变负载时，COF 也是可用的。