The Study Of The Influence Of Underwater Robot To The Optical Pumping Magnetometer And Elimination Algorithm

Underwater robot carrier is the preferred tool for underwater cruise,mineral exploration,topographic survey and other fields.In the complicated environment,having a safer,more efficient and stable operation level than the manual method,thus it has very broad application prospects and fields.During the process of cruise,the measurement of geomagnetic field conducted by underwater robot is influenced by the carrier itself,which affects the measurement accuracy and is very unfavorable for underwater geomagnetic detection.The main sources of interference are magnetizing interference of carrier ferromagnetic materials,strong electromagnetic interference of high power propulsion and high frequency electromagnetic radiation interference of carrier control circuit.In this paper,the cause and mechanism of carrier magnetization interference source are analyzed primarily.Furthermore,the leakage magnetic field of high power brushless DC motor(BLDCM)on the carrier is analyzed and experimented.By using finite element analysis software Comsol Multiphysics,a two-dimensional magnetic flux leakage model of BLDCM is built,also the static leakage field and the dynamic magnetic flux leakage field during rotation for the BLDCM are solved respectively.The results show the BLDCM magnetic flux leakage characteristics near field.In the experiment,the optical pump magnetometer was used as the geomagnetic measuring sensor and use it to measure the leakage current of a brushless DC motor.The results of the leakage magnetic field are consistent with the simulation results.The way to eliminate the AC magnetic interference source of a brushless DC motor is to use a FIR filter.When process the geomagnetic measurement data,the ICA algorithm is used to verify the effectiveness of the algorithm.Finally,combining the FIR low-pass filter and ICA algorithm,the hardware system of eliminating magnetic interference is constructed by using FPGA system,which makes preparations for the real-time interference of underwater robot and obtaining more accurate magnetic field value.