KR20160002103A

KR20160002103A - Automatic calibration method for geomagnetic sensor

Info

Publication number: KR20160002103A
Application number: KR1020140080920A
Authority: KR
Inventors: 반호영; 유경환
Original assignee: 주식회사 네오펙트
Priority date: 2014-06-30
Filing date: 2014-06-30
Publication date: 2016-01-07

Abstract

The present invention relates to a calibration method, and more particularly, to a calibration method capable of calibrating after storing a trajectory and geomagnetism value of a geomagnetic sensor using a trace of a direction indicated by a gravitational acceleration recognized by an acceleration sensor And automatically calibrating the geomagnetism sensor when it is determined that all the values of the geomagnetic sensor have been collected.

Description

Technical Field [0001] The present invention relates to an automatic calibration method for a geomagnetic sensor,

In general, a geomagnetic sensor is a device that detects a very small geomagnetism and specifies its azimuth, so it is susceptible to magnetism by a surrounding magnetic source and a detection error is generated depending on the environment. Therefore, in order to obtain an accurate measurement result using the geomagnetic sensor, the calibration process of the geomagnetic sensor, that is, the calibration, has to be appropriately performed before the measurement.

Therefore, we can obtain Yaw, Pitch, Roll by using 9 axis sensor composed of three axes of acceleration sensors x, y and z, three axes of gyro sensor x, y and z, and three axes of geomagnetic sensor x, y and z The acceleration sensor and the gyro sensor measure at the center of the sensor, so that no error occurs even if no separate calibration is performed. However, in the case of the geomagnetic sensor, there is a problem that the acceleration sensor and the gyro sensor do not.

In other words, if the acceleration sensor does not move, only the gravitational acceleration acts on the three axes, so that the values are the same and the magnitude values in the opposite direction are the same. The acceleration sensor and the gyro sensor do not generate an error even if they are measured without correction processing.

However, since the geomagnetic sensor measures a geomagnetic field of the north pole, a shift phenomenon appears at the central portion due to the peripheral magnetic field. Therefore, if the correction process, i.e., calibration is not performed, There is a problem that a deviation occurs severely every time.

Such a geomagnetic sensor is a sensor used for detecting geomagnetism in the x, y and z axis directions as shown in Fig. 2. The sensor is usually measured in Gaussian units, and an object having a magnetic field component such as iron A shift phenomenon will occur.

Therefore, in the normal case, the center of the geomagnetic sensor is positioned at the center of the geomagnetic sensor, so the magnitude of the geomagnetism measured by the geomagnetism sensor is correct, but the influence of the change of the position of the geomagnetic sensor, When a shift phenomenon occurs in a battery, a circuit, a screw, an external mechanism, etc., the center of the sensor and the geomagnetic measurement zoom axis become different from each other, so that it is difficult to reliably estimate the magnitude of the geomagnetism measured by the supporting sensor.

Of course, in the case where the geomagnetic sensor is fixedly installed at a predetermined position, if the positional relationship with the surrounding magnetic field is the same, the geomagnetism sensor can obtain a sufficiently accurate measurement result even if the calibration is not performed frequently. In case of carrying or moving it, the position of the magnetism sensor in the vicinity as well as the position of the magnetism is changed continuously. Therefore, if the calibration is not performed more frequently than the fixed type geomagnetic sensor, Can not be obtained.

In order to improve the reliability of the geomagnetism value measured by matching the center of geomagnetism measurement due to the shift phenomenon of the geomagnetic sensor to the center of the normal case, that is, the center of the sensor, conventionally, , We used the geomagnetic sensor to make all the measurable ranges form the spheres, and then set the center of the geomagnetic measurement as the center of the spheres.

However, when the sensors including the geomagnetic sensor are rotated several times for the calibration, there is a problem in that time and effort are required for the calibration every time the geomagnetic sensor is used. Even if the user moves There was a need to repeatedly perform the calibration again.

Korean Patent Publication No. 10-2013-0140172

According to the present invention, after storing the trajectory and geomagnetism value of the geomagnetism sensor using the trace of the direction indicated by the gravitational acceleration recognized by the acceleration sensor, if it is determined that all the values capable of calibration are collected, And an automatic calibration method of a geomagnetism sensor capable of operating the calibration of the sensor.

A method of automatically calibrating a geomagnetic sensor for solving the above-

A 9-axis sensor consisting of an acceleration sensor, a gyro sensor and a geomagnetic sensor was rotated from 360 degrees toward the front in the state A, which was laid horizontally, and then trajectory and geomagnetic values were obtained. B state; Rotating the 9-axis sensor 360 degrees from the B state to 360 degrees to obtain a trajectory and a geomagnetic value, rotating the 9 axis sensor 90 degrees from the left side to the right side to make a C state; And obtaining the trajectory and the geomagnetic value by rotating the 9-axis sensor 360 degrees from the C-state toward the front.

The present invention has the effect of automatically performing geomagnetism calibration operation at any time based on data obtained from the acceleration sensor, even if the user moves without the user having to turn the geomagnetism sensor several times for calibration.

1 is an exemplary view showing a measurement deviation occurring in a geomagnetic sensor in which calibration is not performed;
Fig. 2 is an exemplary diagram showing that the geomagnetism measurement values are measured differently in the geomagnetic sensor in the normal case and when the shift phenomenon occurs. Fig.
3 is a view showing a process of turning a 9-axis sensor including a geomagnetic sensor according to the present invention.
4 is a diagram showing a concept of an arithmetic processing process for calibrating a geomagnetic sensor to match a geomagnetic measurement center to the center of the sensor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a diagram showing a process of turning a 9-axis sensor including a geomagnetic sensor according to the present invention, and FIG. 4 is a diagram illustrating a concept of a calculation process of calibrating a geomagnetism sensor and matching the geomagnetism measurement center to the center of the sensor .

3 and 4, a method for automatically calibrating a geomagnetism sensor according to the present invention includes: a 9-axis sensor 100 including an acceleration sensor, a gyro sensor, and a geomagnetic sensor; (1) to make a B state by rotating (2) 90 degrees so as to face upward from the left side to the right side, and (9) rotating the 9-axis sensor 100 by 360 degrees (2) to make a C state by rotating 90 degrees toward the front from the left side to the right side. And rotating the 9-axis sensor 100 360 degrees from the C state toward the front.

In order to align the geomagnetic center of the geomagnetic sensor with the center of the sensor in the 9-axis sensor equipped with the geomagnetic sensor with the geomagnetic measurement center shifted as described above, the 9- And 360 degrees from the C state to the front, it is possible to grasp the locus of the geomagnetism sensor, and then to calibrate the geomagnetism value in each locus.

At this time, the trajectory of the geomagnetic sensor and the geomagnetism value in each locus can be shifted by locus and geomagnetism value using a trace indicating the direction of gravitational acceleration by the acceleration sensor at the time of rotation in the A, B and C states do.

A, B, C, A, C, B, B, C, B, C, A, C, C → A → B, and C → B → A in any order.

The Min and Max values in the X, Y, and Z axis directions are obtained based on the trajectory obtained by rotating 360 degrees in the A, B, and C states and the geomagnetic values on each trajectory, The length and center are calculated. At this time, the length of the value is obtained by ABS (Max - Min), and the measurement center can be obtained by (Min + Max) / 2.

By thus shifting the center value obtained by each measurement value and normalizing the obtained length by dividing the obtained length, the calibration of matching the center of the geomagnetic sensor with the center of the sensor is facilitated.

In this way, the 9-axis sensor equipped with the geomagnetic sensor is rotated 360 degrees in the states of A, B and C to obtain the trajectory and the geomagnetism value, and the resultant shift is made so that, even after the movement after the calibration, Knowing that you can always run the geomagnetism calibration pendulum automatically, you do not have to repeat the calibration process.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

100 - 9 axis sensor

Claims

A 9-axis sensor consisting of an acceleration sensor, a gyro sensor and a geomagnetic sensor was rotated from 360 ° toward the front in the state A lying down in the transverse direction to obtain the trajectory and the geomagnetic value and then rotated 90 degrees from the left toward the right B state;
Rotating the 9-axis sensor 360 degrees from the B state to 360 degrees to obtain the trajectory and the geomagnetism value, rotating the 9 axis sensor 90 degrees from the left side to the right side to make a C state; And
And rotating the 9-axis sensor 360 degrees from the C-axis toward the front to obtain a trajectory and a geomagnetism value.