Research on strain field monitoring system of irregular surface workpiece

In order to ensure the assembly precision in the digital assembly process of large workpiece and reduce the assembly error caused by the standard point coordinate offset caused by surface deformation, an irregular surface workpiece strain field monitoring system based on FBG sensing array was designed. The system tests the surface deformation of the workpiece with gradient features by means of an FBG array laid on the surface of the workpiece. It can calculate the micro-displacement offset of the standard point of the workpiece. The simulation results show that the strain is related to the position, size and workpiece structure of the force application. The strain field has a significant gradient change on the surface of the workpiece. In the experiment, the FBG array arrangement was completed according to the strain gradient feature distribution. Each FBG can effectively acquire the dependent variable at each point. The relationship between the amount of micro-displacement and the wavelength shift under different applied conditions is obtained. The error distribution of the micro-displacement amount is calculated. It verifies the feasibility of the system.