研究了铁镓合金(Galfenol)的磁致伸缩特性, 提出一种基于Galfenol的新型磁致伸缩压力传感器,以实现机器人的触觉力精确感知。该传感器利用磁致伸缩逆效应将压力转换为电压信号, 从而完成对压力的精确测量。设计、制作了磁致伸缩压力传感器, 采用双永磁体回形磁路优化了压力传感器的磁场。对传感器进行了理论分析与实验研究, 讨论了偏置条件、外压力等因素对输出电压峰值的影响。实验结果表明, 在偏置磁场为4.8 kA/m、施加的压力为2.5 Hz、6 N时, 传感器的输出电压峰值达16 mV, 且输出电压峰值与压力呈较好的线性关系。研制的传感器具有结构简单、线性度好、反应速度快等特点, 可以满足机器人触觉感知的需求, 也可应用于其他领域的压力测量。

A pressure tactile sensor based on the fiber Bragg grating (FBG) array is introduced in this paper, and the numerical simulation of its elastic body was implemented by finite element software (ANSYS). On the basis of simulation, fiber Bragg grating strings were implanted in flexible silicone to realize the sensor fabrication process, and a testing system was built. A series of calibration tests were done via the high precision universal press machine. The tactile sensor array perceived external pressure, which is demodulated by the fiber grating demodulation instrument, and three-dimension pictures were programmed to display visually the position and size. At the same time, a dynamic contact experiment of the sensor was conducted for simulating robot encountering other objects in the unknown environment. The experimental results show that the sensor has good linearity, repeatability, and has the good effect of dynamic response, and its pressure sensitivity was 0.03 nm/N. In addition, the sensor also has advantages of anti-electromagnetic interference, good flexibility, simple structure, low cost and so on, which is expected to be used in the wearable artificial skin in the future.