The Development Of A Cable Force Detecting System Based On The Magneto Elastic Effect

Among the modern engineering building structure,the steel cable has been widely used by all kinds of large span Bridges,sports venues,opera,etc.These buildings are closely related to people's lives,and as their supporting structure,the steel cable's security situation is very important.Cable force is the important indicator as the judgment that steel cable structure works normally or not,so the detection of cable force has the vital significance to the analysis of structure health status of steel cable.As a new type of cable force measurement technology,the magneto elastic effect method has the advantages of long-term dynamic monitoring,so developing a set of cable force detection system based on this method has important application value.The paper first expounds the basic principle of cable force measurement based on the magneto elastic effect,and the corresponding formula for cable force measurement are deduced.And then two kinds structure's magnetic flux sensors,the sleeve and the bypass type,are designed for determination of cable force.Next,through ANSYS simulation software,the two magnetic flux cable force sensors are simulated,and the sensors' working conditions for the electromagnetic simulation is analyzed.Then,the hardware and software of flux sensor cable force measurement instrument are designed.Cable force measurement instrument hardware includes MCU master controller,the excitation circuit,sensor signal conditioning and acquisition circuit,wire temperature acquisition circuit,LCD display circuit,serial communication circuit,JTAG interface circuit,etc.Cable force measurement instrument software includes the application of single chip processor system and PC application.The application of single chip processor system based on the STM32 is designed,including excitation signal control,data acquisition and processing,LCD display,serial communication,etc.,PC application based on LabVIEW is designed,including upper and lower position machine communication module,data acquisition curve display and data storage of TXT file,etc.Finally,the measurement system is produced physically,and a set of manual pull testframe is designed.In the laboratory,the two kinds structures' magnetic flux sensor and the cable force measurement instrument are tested,and through the wire free state experiment and the pull experiment,a large number of experimental data are recorded,then the data are processed and analyzed.The experimental results verifies the correctness of two structures' magnetic flux sensor based on theoretical calculation and simulation analysis and the availability of the cable force detection system.