基于SSA-ELM的双层十字梁结构光纤布拉格光栅传感器三维力解耦

针对三维力传感器维间耦合干扰严重的问题,以双层十字梁结构光纤布拉格光栅三维力传感器为研究对象,提出了基于麻雀搜索算法优化极限学习机(Sparrow Search Algorithm–Extreme Learning Machine,SSA-ELM)的解耦算法。首先,研究了光纤布拉格光栅的传感及测力原理,揭示该三维力传感器波长漂移量和力的映射关系,分析其结构耦合特性;然后,构建标定实验系统进行标定实验;最后,建立了极限学习机非线性解耦模型,利用麻雀搜索算法优化模型,获得网络最佳初始权值和阈值,兼顾解耦精度和效率,寻找极限学习机隐含层节点与SSA迭代次数的最优参数组合,解耦后Ⅰ类误差最大为1.18%,Ⅱ类误差最大为1.14%,解耦训练时间为1.7786 s。为验证解耦效果,将SSA-ELM算法与最小二乘法、极限学习机算法解耦结果对比。实验结果表明:SSA-ELM算法解耦训练速度较快,能更有效地构建三维力的维间耦合关系,降低传感器Ⅰ,Ⅱ类误差,具有较好的非线性解耦能力。

FBG sensor of double-layer cross beam structure based on SSA-ELM three-dimensional force decoupling

Aiming to address the problem of severe inter-dimensional coupling interference of three-dimensional force sensors,a decoupling algorithm based on the sparrow search algorithm–extreme learning machine(SSA–ELM)is proposed considering a fiber Bragg grating(FBG)three-dimensional force sensor with a double-layer cross beam structure as the research object.First,the sensing and force measurement principle of FBGs is studied,the mapping relationship between wavelength drift and the force of the threedimensional force sensor is revealed,and its structural coupling characteristics are analyzed.Then,a calibration experiment system is constructed to perform calibration experiments.Finally,a nonlinear decoupling model of extreme learning machine(ELM)is established,and the sparrow search algorithm(SSA)is used to optimize the model to obtain the optimal initial weight and threshold of the network.Considering the decoupling accuracy and efficiency,the optimal number of ELM hidden layer nodes and optimal number of SSA iterations are determined.After decoupling,the maximum type I error is 1.18%,the maximum type II error is 1.14%,and the decoupling training time is 1.7786 s.At the same time,in order to verify the decoupling effect,the decoupling results of the SSA–ELM algorithm are compared with least squares and ELM algorithm.The experimental results show that the SSA–ELM algorithm has a short decoupling training time,can more effectively construct the dimensional coupling relationship of the three-dimensional force,reduce the type I and II errors of the sensors,and has a good nonlinear decoupling ability.