| The three-dimensional electromagnetic positioning technology has the advantage of being unobstructed by the line of sight.It is a technique for acquiring the position and attitude parameters of the target object by using electromagnetic signals.Compared with other positioning technologies,it can obtain more perfect detection target position and attitude information.It is more convenient to move in space,and it is a research hotspot in the field of electromagnetic positioning.It is widely used in sports analysis,medical equipment,virtual reality and other fields.In modern medical minimally invasive surgery,the use of threedimensional electromagnetic positioning system and medical imaging technology can accurately detect the specific position and posture information of the medical device in the human body,which can facilitate the doctor to diagnose the disease and greatly improve the success rate of the operation.Firstly,on the basis of studying the mathematical model of magnetic dipole three-dimensional positioning,the basic coordinate model of electromagnetic localization of this subject is proposed.Then we analyze the method of solving the rotation matrix method and the Euler angle.For the problem that the analysis is very difficult and there are singular points,the quaternions method for reimproving the electromagnetic positioning calculation method is proposed,which can simultaneously solve the position and attitude information of the detection target.Simplifies the solution steps and shortens the solution time.We design the electromagnetic positioning system hardware platform,including the transmitting end coil,the receiving end sensor,the A/D conversion circuit,the power amplifying circuit and so on.In the design of the receiving end sensor,comparing the size structure and data parameters of various magnetic sensors,we adopt a coil sensor with a wider magnetic field detection range and easier miniaturization as the end receiving sensor of the system,which is different from the conventional coil type sensor.This project designed a 0.5mm diameter coil sensor to meet the limitations of medical minimally invasive surgery on the size of medical devices.For the problem of insufficient magnetic field strength caused by small size,a Cobased amorphous alloy with a Co content of about 80% was developed.The wire as its core enhances the magnetic inductive strength of the microcoil.Finally,combined with the experimental data and the waveform received by the oscilloscope,the sensor made by the micro-coil combined with the Co-based amorphous alloy core can be well adapted to medical surgery.Among them,the positioning accuracy is improved to meet the design requirements. |
