Study On The Spindle Temperature Measurement Based On Fiber Bragg Grating Sensors

Now, in finish machining, thermal error can contribute40%-70%to the total error of a workpiece that it becomes the major effect factor to working accuracy of CNC machine. Error compensation is the main method to reduce the thermal error and improve the accuracy at present. To achieve compensation work of thermal error, the first step is to get the temperature field of machine tool, while there are several deficiencies in traditional temperature measurement system. In contrast, Fiber Bragg Grating (FBG) temperature sensor with its virtue becomes an alternative to detect the machine temperature. FBG is reliability and safety, small size and simple structure; moreover, it is anti-electromagnetic interference, corrosion resistance, temperature measurement with linearity output, and can realize quasi-distribution measurement.Bare FBG generally can not be directly applied to actual projects. Encapsulation design is the key for FBG to practical use rather than laboratory research. It can be found throughout the study of FBG temperature sensor, while there are many applications to kinds of test environment with packaging research, FBG packaging study for surface temperature measurement is little. Consequently, with theoretical analysis and experiment research, the author borrows idea from other’s design and improves the structure then applies FBG to temperature measurement of machine tool spindle and study the practice performance compared with a reference temperature measurement system.First, this paper introduces the situation about actual measurement of temperature field of CNC machine domestic and external, as well as the research that making use of FBG as temperature sensor, and then determines to apply FBG to temperature measurement of the machine tool spindle. Next, the thesis explains the basic principle of fiber grating sensor, describes FBG strain, temperature sensing model and cross sensitive problem, analyzes the significance of encapsulation, the requirements and methods. At the same time, this article researches on the static characteristics of bare FBG, through improvement, a new sensor with cassette package structure is designed, then study its performance using experiment and simulation method. After that, the author designs two sets of temperature measurement system-resistance temperature measuring system and the FBG temperature measurement system, the former is a reference system, by the comparing experiment study of spindle utilizing bare FBG and the cassette package structure FBG finds that the cassette package structure FBG has good performance for spindle temperature measurement, realizes the purpose of applying FBG to surface temperature measurement. Finally, achievements and problems of this paper are summarized and the future researches are also put forward.