A Localization System For Multiple Magnetic Targets Based On Magnetic Sensor Scanning Detection

With the development of science and technology,positioning technology plays an increasingly important role in many fields.In the field of medical research,compared with other positioning techniques,magnetic positioning has the advantage of no radiation and positioning in non-visual state,so that the magnetic positioning system can be used in some occasions that require non-contact measurement and control,and it attract more and more domestic and foreign scholars.At present,for the detection of multiple magnetic targets in three-dimensional space,the magnetic positioning systems usually use a large number of fixed magnetic sensors or magnetic sensor array to obtain magnetic signal,thus to a certain extent,improve the positioning accuracy,but The shortcomings include the existence of individual differences between the magnetic sensors and the positioning range is limited by the detection of the array and so on.In this paper,a localization system for multiple magnetic targets based on magnetic sensor rotation detection is studied.Firstly,the mathematical model of the rotation measurement positioning is established.Magnetic field intensity information is converted into voltage signal by the TMR sensor TMR2303 when the sensor rotates around the magnetic targets.The signal is carried on with amplify process and filter processing,and then the processed electrical signals are converted into digital signals with multi-parallel analog-to-digital conversion chip AD7656A-1.And then the digital signal is sent to the PC through the Bluetooth.LABVIEW software is used on the PC for reading,preprocessing and storing data sent by MCU.A MATLAB script node in LABVIEW is set to achieve the positioning algorithm to solve the three-dimensional coordinates of the magnetic target,and finally positioning data will be displayed through the graphical interface.The design of this system includes the following contents:1.The validation of the mathematical model and the determination of scientificity of the rotation measurement.2.Selection of permanent magnet and the determination of the measuring range of the system.3.The optimization of positioning algorithm and the improved LM algorithm can enhance the positioning accuracy.Finally,the system can realize real-time positioning and dynamic trajectory display of 1 and 2 magnetic targets respectively with a magnetic sensor,and the error is analyzed.The experimental results show that the average accuracy is 0.17cm and a complete data operation takes 17.9 ms when the system locates a permanent magnet;the average accuracy is 0.29cm and a complete data operation takes 63.1 ms when the system locates two permanent magnets.The accuracy of the system can meet the localization of relatively strong magnetic nanoparticles,and the scheme of the system is feasible.With the improvement of the accuracy of the magnetic sensor and the optimization of the localization algorithm,the design scheme of the system has potential value for the positioning of multiple capsule endoscopes and the detection of nano magnetic drugs in the human body.