【作者】 马双；

【导师】 杨文玉；

【作者基本信息】 华中科技大学 ， 机械电子工程， 2011， 硕士

【摘要】 FBG(光纤布喇格光栅)传感器是一种高精度应力应变传感器,目前已广泛应用于大型土木结构以及简单机械结构的健康检测,但一般只停留在较为简单的应力应变检测阶段,而在较为复杂机械系统的FBG应用还属于空白领域。本文针对FBG传感体结构、应变传递特性,以及传感器在巨型重载操作机夹持界面接触力测量中的应用开展研究。其中的主要问题是FBG传感器在检测过程中的维度匹配问题以及非均匀应变的求解方法。为解决在机械系统中广泛存在的FBG传感特性与被测对象的变形之间的维度匹配问题,将FBG传感技术与柔顺机构的传感特性相结合,设计了一个对平面变形敏感的柔顺机构,利用有限元分析软件进行系统特性分析,并建立相应的数学计算模型,最后通过对柔顺机构的平面位移输入量与FBG传感器测量量进行对比和计算,验证其可行性。为解决两物体间接触力的测量问题,引入测量介质,通过有限元方法对传感体结构及其传感特性进行分析,并讨论了由被测对象与FBG传感器之间的尺度相同所引起的非均匀应变问题。引入接触力学中的弹性半空间理论,建立接触界面上的法向接触力与FBG的波长偏移量之间的关系模型。最后,将FBG检测技术应用于青岛华东机械厂锻压操作机钳口接触力的测量,克服了现场环境中光纤易碎、数量大,信号噪声大等问题,测量结果与理论计算结果相符,表明所提出的非均匀应变场检测与识别模型的有效性。更多还原

【Abstract】 FBG (fiber Bragg grating) is a kind of stress-strain sensor with high precision, which recently has been widely used in lots of buildings, dams, bridges, etc, together with simple machines for structural health monitoring. However, the utilization of FBG sensors is only in the simple stress-strain measuring stage, while the one in more complex mechanical systems remains nearly an empty field. So a research has been done on the principle, characteristics and the current application of the FBG sensor. And the main problem is the solution to the Dimension Matching Problem appears in the FBG sensing process and the Non-uniform Strain Problem appears the detecting area.To solve the Dimension Matching Problem that exists in most of the measuring processing between the FBG measuring characteristics and the deformation of objects to be measured a combination about the technologies of the FBG sensing and Compliant Mechanisms has been made, according to which a compliant mechanism that sensitive to the plane strain was made, and then some analysis on the characteristics of the system were done. After establishing the mathematical model, through the comparison and the calculation between the displacement input to the compliant mechanism and the detection output from the FBG sensor, the solution was proved to be a feasible one.To solve the problem on the contact force between two objects, a kind of sensing-medium has been brought in, then the FEM software was used to do some analysis on the sensing-medium structure and the sensing characteristic of it, and the problem on the non-uniform strain on the FBG caused by the same scale of the FBG sensor and the contact interface was discussed. The elastic half-space theory included in contact mechanics has been referred to establish a mathematical model between the normal contact force on the contact interface and the FBG wavelength shift.Finally, by solving the problem on the FBG frangibility, the security of the large number of the FBG sensors, the high noise in the signal and so on, the FBG sensing technology was managed to be used in the contact force measuring experiment on the gripper of the forging manipulating made in Qingdao Huadong Machine Factory. The accordant between the result of the experiment and the theoretical calculation shows that the model proposed previously on the non-uniform strain measuring and identifying is of great valid.更多还原