Research On The Vector Signal Transceiver Technology In Six-degree-of-freedom Electromagnetic Positioning

Six-degree-of-freedom electromagnetic positioning is a kind of technology todetermine the position and attitude of targets by using electromagnetic signal. It cannot only get better information, but also has more advantages such as no sight lineblocking and convenient moving in the space. Six-degree-of-freedom electromagneticpositioning is widely used in the field of virtual reality, medical equipment,biomechanics, movement analysis and so on. It has become one of the hot topics in thefield of electromagnetic positioning.This paper focuses on the research of vector signal transceiver technology in thesix-degree-of-freedom electromagnetic positioning system. According to the law ofelectromagnetic induction and the rotation matrix algorithm, the scheme of theelectromagnetic positioning transceiver is designed. Parameters of the sensor structureare determined by analyzing the frequency, amplitude and other characteristics of thesignals. Then reasonable transmitting and receiving vector sensor are designed. At last,the vector signal transceiver circuits are developed, and its performance testing iscarried on the platform of DSP parameter calculation.The main work and contributions are as follows:(1)The model of the magnetic dipole is analyzed. Some theories are introduced,such as Faraday’s law of electromagnetic induction, Biot-Savart-Laplace law, rotationmatrix positioning algorithm and so on. Based on them, the implementation plan ofsix-degree-of-freedom electromagnetic positioning transceiver device is designed andthe device is set up. Its amplitude amplifier circuit, power amplifier circuit, signalselection circuit and over voltage protection circuit are designed and realized.The LM833CMOS chip is used in transmitting circuit to amplify the amplitude ofthe signals into2.5times. The SSM2211CMOS chip can amplify the power into2times. The over voltage protection circuit uses the SP721AG CMOS chip to keep thevoltage range less than30V. The receiver circuit contains an over voltage protection circuit and the MAX4582CMOS chip to select the received signals in different time.Then the signals can be filtered and amplified by the INA163UA CMOS chip, itsamplification can be changed by adjusting the resistance. According to the scheme ofthe transmitting and receiving circuits, the PCB circuit board is welded and debugged.In the end, the ideal sinusoidal signal can be received.(2) Three-axis orthogonal induction coil sensor is designed and realized. Thestructure parameters of the sensor is obtained, which contain turns per coil anddiameter and so on. The coil sensor is enwound and it is tested and amended byexperiments. The size of the transmitting sensor is determined as10cm*10cm*10cmand the inductance values of its three-axis are902H,837Hand813H. Thesize of receiving sensor is10mm*10mm*10mm, and the inductance values of itsthree-axis are29H,30Hand31H. The structures of both sensors are withoutcore.(3) All of the circuits above are integrated into the DSP positioning parameterscomputing platform. Then the whole six-degree-of-freedom electromagneticpositioning device is tested. In the experiments, the location of transmitting sensor isfixed.10different test positions are selected for receiving sensor. The distanceinformation on the coordinates can be obtained and the attitude information can be gotby changing the pose of object on the fixed location. When the positioning results arecompared with the real location and posture of targets, errors will come out. The casusof error is analyzed and improvement approach is proposed.