Research On Attitude Calculation Algorithm Of Moving Body Based On Inertial-Geomagnetic Combination

The inertial-geomagnetic combination measurement unit is widely used in the fields of medical rehabilitation,sports,virtual reality,and medical device tracking because of its small size,low cost,and low power consumption.The inertial-geomagnetic combination measurement unit is composed of MEMS sensors,which mainly includes hardware and software.The hardware includes accelerometer,gyroscope and magnetometer.The software is a data fusion algorithm(also called an attitude measurement algorithm),and the data is measured by the hardware.The attitude of the moving body is obtained through the data fusion algorithm.In this paper,the research on the attitude measurement algorithm of moving body based on the inertial-geomagnetic combination measurement unit is carried out.The main work is as follows:First,based on different sensor data,several corresponding attitude measurement algorithms are introduced,and the performance of different algorithms is compared and analyzed.Finally,it is determined to use the inertialgeomagnetic unit measurement data for attitude measurement algorithm researching;Second,in view of the influence of three deterministic errors on the sensor output data,a new experimental method for error calibration is proposed.Experiments are carried out based on the MTi-28A53G35 sensor module,and the error parameters are obtained to complete the calibration,and the true sensor output value is deduced by the formula.Meanwhile,it can realize the sensor compensation,and finally obtain the true output value of sensor.It can provide accurate data for the subsequent implementation of attitude measurement algorithm,and eliminate the influence of three deterministic errors on the attitude of the moving body;Finally,in view of the influence of the linear acceleration of the moving body and the interference of the external magnetic field on the attitude measurement accuracy of the moving body,based on the existing inertial-geomagnetic combination measurement unit,a multi-model fusion attitude measurement algorithm is proposed.When using sensor data for attitude measurement,the three sensor data are not directly substituted into the complementary filtering algorithm,but a continuous segment of motion is classified and truncated first,and divided into two segments,dynamic and static,and only gyroscope data is used in the dynamic segment.It is used for attitude measurement.The accelerometer and magnetometer data are used for attitude measurement in the static section,and then the attitude measurement results of each section are combined to obtain the continuous motion attitude of this section.In order to ensure the accuracy of classification,a reliability judgment criterion is proposed for motion state judgment,and an "error estimate" is proposed for the selection of the optimal threshold in the reliability judgment criterion formula to realize accurate recognition of the motion state.According to the different sensor data used,different data fusion models are established,and different states are switched to the corresponding data fusion models.Experiments show that the algorithm has improved measurement accuracy and speed.