JP2011047841A - Electronic azimuth meter, and method for adjusting and manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a calibration processing to be performed in a short time in an electronic azimuth meter with a plurality of stepping motors, and to provide a method for adjusting and manufacturing such an electronic azimuth meter that ensures to reduce process costs by decreasing the time required for the calibration processing. <P>SOLUTION: In performing a calibration processing of an azimuth sensor 53 with orientation of rotors 57a, 62a on a stepping motor in a state of combination patterns of patterns A-D and from the sensor output value of the azimuth sensor 53 with the external magnetic field applied from first to fourth directions I-IV, each sensor output value with the external magnetic field applied from first to fourth directions I-IV is obtained only in a state of pattern A, while the sensor output value with the external magnetic field applied from a first direction I is obtained in a state of patterns B-D, the remaining sensor output value being determined by calculation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic compass having a step motor, a method for adjusting the electronic compass, and a manufacturing method thereof.

  An electronic azimuth meter has been put into practical use that electrically measures azimuth using a magnetic sensor. Some electronic azimuths have a configuration in which a step motor (also referred to as a stepping motor) is mounted inside and one or a plurality of hands are rotated by the step motor.

  The step motor has a configuration in which a magnetized rotor rotates by one step (for example, 180 °), and the direction and magnitude of a magnetic field exerted on the magnetic sensor from the rotor changes depending on the rotation position. The magnetic field exerted from the rotor to the magnetic sensor cannot be accurately measured unless it is removed from the output value of the magnetic sensor by correction.

  Therefore, conventionally, in an electronic azimuth meter having a step motor, there has been proposed a technique for obtaining an azimuth by performing different correction processing for each direction of a magnetic pole of a rotor (for example, Patent Document 1).

  In addition, in the conventional electronic azimuth meter, various errors associated with magnetic detection (for example, the influence of a magnetic material arranged around the magnetic sensor, errors in perpendicularity in two directions where the magnetic field is detected by the magnetic sensor, In order to remove a magnetic sensor mounting angle error, etc., a technique has been proposed in which a calibration process is performed in advance before shipment from the factory to obtain a numerical value necessary for a correction process at the time of azimuth measurement. For example, the calibration technique of Patent Document 2 acquires an output value of a magnetic sensor in an applied state of each external magnetic field while applying an external magnetic field from a plurality of predetermined directions to an electronic azimuth meter, Numerical values for removing the various errors are obtained from these output values.

JP-A-10-170664 JP 2002-048551 A

  When performing the above-described conventional calibration processing for an electronic azimuth meter having a plurality of stepping motors, if there is no ingenuity, from a plurality of predetermined directions for each combination pattern of magnetic pole directions of a plurality of rotors An external magnetic field is applied, and the output of the magnetic sensor in each state is acquired.

For example, it is assumed that there are three stepping motors, each stepping motor has two poles, and an external magnetic field is applied from four directions in the calibration process to obtain the output value of the magnetic sensor. Then, since the rotor orientation combination pattern is 2 ³ = 8 patterns, it is necessary to obtain the output value of the magnetic sensor while changing the orientation of the rotor and the direction of the external magnetic field in 32 patterns of 8 patterns × 4 directions. Arise.

  Thus, as the number of step motors increases, the number of times that the output value of the magnetic sensor must be acquired increases, and the time required for one calibration process becomes longer. Further, in order to correct an error due to individual differences of products, it is assumed that calibration processing is performed for each individual product. In this case, the time required for calibration processing is doubled by the number of products.

  An object of the present invention is to enable calibration processing to be performed in a short time in an electronic azimuth meter equipped with a plurality of step motors. It is another object of the present invention to provide an electronic azimuth meter adjustment method and manufacturing method that can reduce the process cost by shortening the calibration processing time.

In order to achieve the above object, the invention according to claim 1
Multiple stepper motors,
A magnetic sensor;
Polarity direction determining means for determining which combination pattern is a combination pattern of the magnetic pole directions of the plurality of rotors in the plurality of step motors among a predetermined number of combination patterns that can be taken as the combination pattern;
Correction value calculation means for calculating a plurality of azimuth calculation correction values corresponding to the predetermined number of combination patterns;
An azimuth calculating means for correcting an output value of the magnetic sensor based on the correction value for calculating the azimuth corresponding to the combination pattern determined by the polarity direction determining means, and obtaining an azimuth;
An electronic compass with
The correction value calculating means includes
Each output value of the magnetic sensor is stored in a state of a specific combination pattern that is one of the predetermined number of combination patterns and when an external magnetic field is applied separately from a plurality of predetermined directions. First storage control means;
First correction value calculation means for obtaining a correction value for calculating the azimuth for the specific combination pattern based on the output value stored by the first storage control means;
Of the predetermined number of combination patterns that can be taken as the combination pattern, an external magnetic field is applied from each of a plurality of combination patterns other than the specific combination pattern and from a first direction among the plurality of predetermined directions. Second storage control means for storing the output values of the magnetic sensor at the time,
In each state of a plurality of combination patterns other than the specific combination pattern from the output value stored by the first storage control unit and the output value stored by the second storage control unit, and in advance Calculate an output value that should be obtained from the magnetic sensor when an external magnetic field is applied from a direction other than the first direction among a plurality of determined directions, and based on these output values, other than the specific combination pattern Second correction value calculation means for respectively obtaining the azimuth calculation correction value for each of the combination patterns;
It is characterized by having.

The invention according to claim 2 is the electronic azimuth meter according to claim 1,
The first storage control means further stores the output value of the magnetic sensor in the state of the specific combination pattern and when no external magnetic field is applied,
The second correction value calculation means further calculates an output value that should be obtained from the magnetic sensor in each state of a plurality of combination patterns other than the specific combination pattern and when no external magnetic field is applied, The calculation is performed including the output value, and the correction value for calculating the azimuth is obtained.

The invention according to claim 3 is the electronic azimuth meter according to claim 1,
Comprising non-volatile storage means;
The correction values obtained by the first correction value calculation means and the second correction value calculation means are stored in the nonvolatile storage means.

The invention according to claim 4
Multiple stepper motors,
A magnetic sensor;
Polarity direction determining means for determining which combination pattern is a combination pattern of the magnetic pole directions of the plurality of rotors in the plurality of step motors among a predetermined number of combination patterns that can be taken as the combination pattern;
An azimuth calculation unit that corrects the output value of the magnetic sensor according to the combination pattern determined by the polarity direction determination unit and obtains an azimuth;
An electronic compass with
Each output value of the magnetic sensor is stored in a state of a specific combination pattern that is one of the predetermined number of combination patterns and when an external magnetic field is applied separately from a plurality of predetermined directions. First storage control means;
The magnetism when an external magnetic field is applied from a first direction among a plurality of predetermined directions in each state of a plurality of combination patterns other than the specific combination pattern among the predetermined number of combination patterns Second storage control means for storing the output values of the sensors,
First correction value calculation means for obtaining a correction value for calculating an azimuth for the specific combination pattern based on the output value stored by the first storage control means;
Difference storage control means for storing a difference between the output value stored by the first storage control means and the output value stored by the second storage control means;
With
The azimuth calculating means is
When measuring the orientation, when the orientation of the magnetic poles of the plurality of rotors is the specific combination pattern, the output value of the magnetic sensor is corrected by the correction value obtained by the first correction value calculating means to determine the orientation. First azimuth calculating means for calculating,
Difference correction means for correcting the output value of the magnetic sensor by the difference stored in the difference storage means when the direction of the magnetic poles of the plurality of rotors is a combination pattern other than the specific combination pattern when measuring the azimuth. When,
A second azimuth calculating means for correcting the output value corrected by the difference correcting means with the correction value obtained by the first correction value calculating means and calculating an azimuth;
It is characterized by having.

The invention according to claim 5 is the electronic azimuth meter according to claim 4,
The first storage control means further stores the output value of the magnetic sensor in the state of the specific combination pattern and when no external magnetic field is applied,
It is characterized by that.

The invention according to claim 6 is the electronic azimuth meter according to claim 4,
Comprising non-volatile storage means;
The correction value obtained by the first correction value calculation means and the difference stored by the difference storage control means are stored in the nonvolatile storage means.

The invention according to claim 7 is the electronic azimuth meter according to claim 1 or 4,
A working storage means for temporarily storing data;
The first storage control means and the second storage control means are configured to temporarily store the output values of the magnetic sensor in the work storage means.

The invention according to claim 8 is the electronic azimuth meter according to claim 1 or 4,
The step motor is characterized in that the stator has two poles and the rotor has two poles.

The invention according to claim 9 is an adjustment method for performing adjustment for azimuth measurement on the electronic azimuth meter according to claim 3.
An external magnetic field is applied from the first direction among the plurality of predetermined directions to the electronic azimuth meter, and the combination pattern of the magnetic pole directions of the plurality of rotors is switched to all combination patterns. In the meantime, a first step of temporarily storing the output value of the magnetic sensor by the first storage control means and the second storage control means;
An external magnetic field is applied separately from each of the plurality of predetermined directions except the first direction to the electronic azimuth meter, and a combination pattern of magnetic pole directions of the plurality of rotors Is fixed to the specific combination pattern, and in the meantime, the first storage control means temporarily stores the output value of the magnetic sensor;
After the first step and the second step, the first correction value calculation means and the second correction value calculation means are used to output a plurality of combinations corresponding to all combination patterns of the magnetic pole directions of the plurality of rotors. A third step of calculating a correction value and storing it in the non-volatile storage means;
It is characterized by including.

The invention according to claim 10 is an adjustment method for performing adjustment for azimuth measurement on the electronic azimuth meter according to claim 6.
An external magnetic field is applied from the first direction among the plurality of predetermined directions to the electronic azimuth meter, and the combination pattern of the magnetic pole directions of the plurality of rotors is switched to all combination patterns. In the meantime, a first step of temporarily storing the output value of the magnetic sensor by the first storage control means and the second storage control means;
An external magnetic field is applied separately from each of the plurality of predetermined directions except the first direction to the electronic azimuth meter, and a combination pattern of magnetic pole directions of the plurality of rotors Is fixed to the specific combination pattern, and in the meantime, the first storage control means temporarily stores the output value of the magnetic sensor;
After the first step and the second step, the first correction value calculation means calculates a correction value corresponding to the specific combination pattern of the magnetic pole directions of the plurality of rotors, and the correction value, A fourth step of storing the difference to be stored by the difference storage control means in the nonvolatile storage means;
It is characterized by including.

The invention according to claim 11
An assembly process for assembling an electronic compass;
An adjustment step of adjusting by the adjustment method of the electronic compass according to claim 9 or 10,
It is the manufacturing method of the electronic azimuth | direction meter characterized by including.

  According to the present invention, when the direction of the magnetic poles of the rotor is other than the specific combination pattern, only the output value of the magnetic sensor when the external magnetic field is applied only from the first direction can be obtained, and each combination pattern of the rotor direction is supported. Since a plurality of types of azimuth calculation correction values can be acquired, the calibration processing time can be shortened.

It is a block diagram which shows the whole structure of the electronic azimuth | direction meter of 1st Embodiment of this invention. It is a top view which shows a specific example of a direction sensor. It is explanatory drawing which shows each combination pattern of the direction of a rotor in a trimming process, and the application direction of an external magnetic field. It is a data chart showing a plurality of sensor output values acquired by measurement and calculation and temporarily stored during trimming processing. It is a data chart showing the correction value calculated and stored by the trimming process. It is a table | surface which shows the conditional expression at the time of calculating | requiring an azimuth angle in an azimuth | direction measurement process. It is a flowchart which shows the control procedure of the trimming process of 1st Embodiment. It is a flowchart which shows the control procedure of the direction measurement process of 1st Embodiment. It is a data chart which shows the several sensor output value acquired during the trimming process and temporarily stored in 2nd Embodiment. It is a data chart showing the correction value calculated and memorize | stored by the trimming process of 2nd Embodiment. It is a data chart showing the difference data of the sensor output value memorize | stored by the trimming process of 2nd Embodiment. It is a flowchart which shows the control procedure of the trimming process of 2nd Embodiment. It is a flowchart which shows the control procedure of the direction measurement process of 2nd Embodiment.

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

[First Embodiment]
FIG. 1 is a block diagram showing the overall configuration of the electronic azimuth meter according to the first embodiment of the present invention.

  An electronic azimuth meter 1 according to this embodiment includes a clock function that displays a time by rotating a plurality of hands (second hand, hour hand, minute hand), and an electronic azimuth meter that indicates a specific direction (for example, magnetic north) using the second hand. For example, it is in the form of an arm-mounted type. As shown in FIG. 1, the electronic azimuth meter 1 includes a step motor 62 that drives the second hand step by step, a motor drive circuit 63 that supplies a drive current to the step motor 62, and the magnetic poles of the rotor of the step motor 62. A polarity storage circuit 64 for storing the direction, a plurality of gears connected to each other, and a second hand drive mechanism 65 for transmitting the rotational movement of the step motor 62 to rotate the second hand, and an hour hand and a minute hand are interlocked to drive step by step. A step motor 57, a motor drive circuit 58 for supplying a drive current to the step motor 57, a polarity storage circuit 59 for storing the orientation of the magnetic poles of the rotor of the step motor 57, and a plurality of gears are connected to each other. And an hour / minute hand drive mechanism 60 for transmitting the rotational movement to rotate the hour hand and the minute hand.

  The electronic azimuth meter 1 includes a control unit 40 that incorporates a CPU and performs overall control of the apparatus, a ROM 46 that stores control programs and control data executed by the CPU of the control unit 40, and a control unit. RAM 47 as work storage means for providing a work memory space for 40 CPUs, EEPROM (electrically erasable programmable ROM) 45 as non-volatile storage means in which various setting data are written after board mounting, An oscillation circuit 48 and a frequency dividing circuit 49 for generating a signal with a constant period for use, a time counting circuit 50 for counting the signals of the frequency dividing circuit 49 and measuring time, a power source unit 51 for supplying power to each unit, an external The operation unit 52 for inputting the operation command from the azimuth sensor, the azimuth sensor 53 as a magnetic sensor for detecting the magnetic field, and the detection signals of the azimuth sensor 53 are combined to detect each of the two detection directions. An azimuth detecting unit 54 that generates a sensor output value representing the magnitude of the magnetic field is provided.

  The step motors 57 and 62 are each provided with a two-pole stator and two-pole rotors 57a and 62a (see FIG. 3), and a positive drive current is caused to flow through a coil wound around the stator. The rotor rotates from 0 ° to 180 °, and the rotor rotates from 180 ° to 360 ° by passing a negative drive current through the coil. Since the rotor is magnetized in two poles, the direction and magnitude of the magnetic field exerted from the rotor to the surroundings are changed depending on whether the rotation angle is 0 ° or 180 °.

  The polarity storage circuits 59 and 64 are circuits that detect and hold the polarity of the drive current output immediately before from the motor drive circuits 58 and 63 to the step motors 57 and 62. The direction of the magnetic poles of the rotors of the step motors 57 and 62 can be identified by the retained polarity data. These polarity storage circuits 59 and 64 and the CPU of the control unit 40 constitute a polarity direction discrimination means.

  FIG. 2 is a plan view showing a specific example of the direction sensor 53.

  The direction sensor 53 is a device that detects a magnetic field in two directions intersecting with each other (for example, an X direction and a Y direction that are orthogonal to each other). Specifically, as shown in FIG. 2, four magnetoresistive elements MR1 to MR4 and external connection pads Pd1 to Pd4 are formed on a substrate 63a, and bias magnetic fields B1 to B4 are applied to the substrate 63a. Bias coils CL1 and CL2 for generation are wound around. The four magnetoresistive elements MR1 to MR4 are disposed on the substrate 63a so as to be rotated symmetrically by 90 ° in order, and terminals of the magnetoresistive elements MR1 to MR4 adjacent to each other are connected to each other. The terminal connection portion and the pads Pd1, Pd2, Pd3, and Pd4 are electrically connected. A predetermined DC voltage V is applied between the pair of opposed pads Pd1 and Pd3, and the detection voltages PS1 and PS2 are output to the remaining pair of opposed pads Pd2 and Pd4. .

  According to the azimuth sensor 53 described above, the detection voltages PS1 and PS2 are output while the phase inversion currents are sequentially supplied to the bias coils CL1 and CL2, thereby measuring the magnetic fields in the X direction and the Y direction as follows. It is possible. That is, first, depending on the voltage value when the difference voltage between the detection voltages PS1 and PS2 when the bias magnetic field B2 is generated is subtracted from the difference voltage between the detection voltages PS1 and PS2 when the bias magnetic field B1 is generated, The magnitude of the X direction component of the magnetic field applied to the sensor 53 from the outside is measured. Next, the direction sensor is obtained by subtracting the differential voltage between the detection voltages PS1 and PS2 when the bias magnetic field B4 is generated from the differential voltage between the detection voltages PS1 and PS2 when the bias magnetic field B3 is generated. The magnitude of the Y direction component of the magnetic field applied to 53 from the outside is measured.

  The azimuth detecting unit 54 converts the differential voltage between the detection voltages PS1 and PS2 of the azimuth sensor 53 into digital data, and for the digital data of each differential voltage when the bias magnetic fields B1 to B4 are applied, respectively. By performing the above arithmetic processing, the sensor output value “X” indicating the magnitude of the X direction component of the magnetic field applied from the outside to the direction sensor 53 and the sensor output value “Y” indicating the magnitude of the Y direction component. Are supplied to the control unit 40.

  The azimuth sensor 53 is mounted on the electronic azimuth meter 1 so that the X direction overlaps the 12:00 direction of the dial, for example, and a sensor output value indicating the magnitude of the magnetic field in the X direction from the azimuth detection unit 54 and the Y direction It is possible to calculate which direction the electronic azimuth meter 1 is facing with respect to the geomagnetism based on the sensor output value representing the magnitude of the magnetic field.

  In the above azimuth sensor 53, the following error occurs when measuring the direction of the magnetic field exerted from the outside of the electronic azimuth meter 1. That is, the error in the perpendicularity of the magnetic field detection direction (X direction and Y direction) based on the deviation of the formation direction of the magnetoresistive elements MR1 to MR4 and the winding direction of the bias coils CL1 and CL2, the mounting angle of the orientation sensor 53 with respect to the device , A difference in detection sensitivity between the X direction and the Y direction of the azimuth sensor 53, and an offset error based on the magnetic field exerted from the rotors of the step motors 57 and 62. Among these, the sensitivity error between the X direction and the Y direction of the azimuth sensor 53 includes not only the sensitivity error of the azimuth sensor 53 itself but also the sensitivity error due to the magnetic body arranged around the azimuth sensor 53. That is, when there is a magnetic body around the orientation sensor 53, an external magnetic field such as geomagnetism magnetizes the magnetic body, so that a new magnetic field based on this magnetization is exerted on the orientation sensor 53. Therefore, an error occurs in the detection sensitivity of the azimuth sensor 53 in the X direction and the Y direction due to the arrangement of the surrounding magnetic bodies.

  In the ROM 46, as a control program executed by the CPU of the control unit 40, a time display program for driving the motor drive circuits 58 and 63 with the passage of time to display the time on the dial, and detection of the direction are detected. An azimuth meter program that drives the second hand while pointing it repeatedly and points to a specific azimuth, a trimming processing program that calibrates the azimuth sensor 53 in an adjustment process before factory shipment, and the like are included.

  In the EEPROM 45, a correction value storage unit 45a is set, and correction value data of the azimuth sensor 53 obtained by the trimming process is stored in the correction value storage unit 45a.

  Next, the operation of the electronic azimuth meter 1 configured as described above will be described.

[Time display processing]
The time display process is performed by the CPU of the control unit 40 executing a time display program in the time display mode or the direction meter mode. In the time display mode, the CPU of the control unit 40 outputs a drive pulse to the motor drive circuit 63 for driving the second hand every time a 1-second signal is input from the frequency divider 49, and also outputs a 10-second signal from the time measuring circuit 50 Each time an input is made, a drive pulse is output to the motor drive circuit 58 for driving the hour / minute hands. The 1 second signal is a signal output every 1 second, and the 10 second signal is a signal output every 10 seconds. By these operations, the second hand is moved one step every second, and the hour hand and minute hand are moved one step every 10 seconds, and the time is displayed by this hand movement operation.

  On the other hand, in the direction meter mode, the CPU of the control unit 40 executes the time display program in parallel with the direction meter program, and does not output the drive pulse based on the 1 second signal, but from the time measuring circuit 50. Each time a 10-second signal is input, a drive pulse is output to the motor drive circuit 58 for driving the hour / minute hand. By this operation, even in the compass mode, the hour hand and the minute hand are moved step by step every 10 seconds, and the hour and minute values of the time are displayed.

[Direction processing]
The compass processing is started when the CPU of the control unit 40 shifts to compass program processing, for example, when the user inputs an operation command to switch to compass mode from the outside via the operation unit 52. In the azimuth meter process, the azimuth sensor 53 and the azimuth detector 54 are repeatedly operated at predetermined time intervals, and a sensor output value indicating the result of the azimuth measurement is supplied from the azimuth detector 54 to the CPU of the controller 40. The CPU of the control unit 40 performs a calculation based on the sensor output value to determine the orientation of the electronic azimuth meter 1 with respect to the geomagnetism (for example, the orientation indicated by the 12 o'clock position on the dial).

  When calculating the direction, the CPU of the control unit 40 reads the data stored in the polarity storage circuits 59 and 64, and determines the combination pattern of the orientations of the magnetic poles of the rotors 57a and 62a of the step motors 57 and 62. Then, the correction value corresponding to this combination pattern is read from the correction value storage unit 45a, and the azimuth is calculated using this correction value. A direction calculation method using this correction value will be described in detail later.

  When the orientation of the electronic azimuth meter 1 with respect to geomagnetism is determined, the CPU of the control unit 40 then determines which angular position on the dial matches the direction of magnetic north and drives the second hand to this angular position. Then, by repeatedly performing such measurement of the azimuth and driving of the second hand, a specific azimuth is constantly indicated by the second hand, and the user can obtain the azimuth from the position of the second hand.

[Trimming]
Trimming processing includes an error in perpendicularity between the X direction and the Y direction, which are magnetic detection directions of the azimuth sensor 53, an error in the mounting angle of the azimuth sensor 53 (for example, a deviation between the X direction and the 12 o'clock direction of the dial), an Correction values for removing the detection sensitivity error in the X and Y directions of the sensor 53 and the offset error due to the magnetic field exerted on the azimuth sensor 53 from the rotors 57a and 62a of the step motors 57 and 62 are obtained. This is processing to be stored in the correction value storage unit 45a. The trimming process is executed by the CPU of the control unit 40 to constitute a correction value calculation means.

  The trimming process is performed in an environment in which an external magnetic field having a predetermined magnitude can be applied to the electronic azimuth meter 1 from a predetermined direction. For example, the trimming process is performed in an adjustment process after the assembly process in the product manufacturing process. It is what is said. This trimming process is started when the operator inputs a specific operation command via the operation unit 52 or the like in the above environment. During this trimming process, the CPU 40 of the control unit 40 does not execute the time display process.

  FIG. 3 is an explanatory diagram showing each combination pattern of the rotor orientation and the application direction of the external magnetic field in the trimming process, and FIG. 4 shows a plurality of temporarily acquired and obtained by measurement and calculation during the trimming process. The data chart showing the sensor output value of is shown. In FIG. 3, 1A represents the housing of the electronic azimuth meter 1, 57a and 62a represent the rotors of the step motors 57 and 62, and I to IV represent the direction of application of the external magnetic field.

  In the trimming process, first, the CPU of the control unit 40 operates the azimuth sensor 53 and the azimuth detection unit 54 in each of the following states, and acquires sensor output values in the X direction and the Y direction from the azimuth detection unit 54, respectively. That is, the combination pattern of the magnetic pole directions of the rotors 57a and 62a is in the state of the pattern A (specific combination pattern) shown in FIG. 3A, and an external magnetic field is applied individually in the first direction I to the fourth direction IV. The combination patterns of the sensor output values when applied and when no external magnetic field is applied and the orientations of the polarities of the rotors 57a and 62a are the patterns B to B shown in FIGS. Each sensor output value when the external magnetic field is applied from the first direction I in the state of D is acquired.

  Note that the order in which these sensor output values are acquired is not particularly limited. For example, if it takes more time to switch the application direction of the external magnetic field than to switch the direction of the rotors 57a and 62a, first, the direction of the rotors 57a and 62a in the state where the external magnetic field is applied from the first direction I. The sensor output value of each state is obtained by changing the combination pattern of patterns A to D, and then the rotors 57a and 62a are combined with the pattern A, and the external magnetic field is sequentially applied in the second direction II to the fourth direction IV. The sensor output value in each state may be acquired by changing the application direction.

  And if each said sensor output value is acquired, these sensor output values will be temporarily stored in the predetermined area | region of RAM47. The sensor output value temporarily stored here is the data described in the white background item in the data chart of FIG.

  In FIG. 4, the sensor output value related to magnetic field detection in the X direction of the azimuth sensor 53 is represented by a variable symbol “X”, and the sensor output value related to magnetic field detection in the Y direction is represented by a variable symbol “Y”. The combination of the orientations of the rotors 57a and 62a indicates the sensor output value in any of the patterns A to D. The subscripts “A to D” indicate the external magnetic fields in the first direction I to the fourth direction. Whether the sensor output value is applied from any of the directions IV or the sensor output value when no external magnetic field is applied is represented by the subscripts “1 to 4, 0”. .

  After acquiring the sensor output value as described above, the CPU of the control unit 40 next causes the rotors 57a and 62a to be in the patterns B to D and the external magnetic field from the second direction II to the fourth direction IV to be generated. Each sensor output value when it is applied and when no external magnetic field is applied is obtained by calculation. The sensor output value calculated here and temporarily stored in the RAM 47 is data described in the shaded item in the data chart of FIG.

The calculation of the sensor output value is executed by the following equation based on other sensor output values temporarily stored in the RAM 47.

Here, only the calculation formulas of the sensor output values X _B2 , Y _B2 , X _B3 , and Y _B3 are shown, but other sensor output values can be obtained by the same calculation formula. Corresponding to the sensor output value to be calculated, the subscript of each term on the left side and the right side is changed in the same manner, whereby a calculation formula for obtaining each sensor output value can be derived.

The calculation formula for calculating each sensor output value is obtained by the following logic. For example, the calculation formula (1) will be described. First, the pattern A and the pattern B differ only in the combination of the orientations of the rotors 57a and 62a. Therefore, the rotor 57a, if there is no influence of 62a, the sensor output value _{X A2} of the sensor output value _{X B2} and pattern A pattern B should be equivalent. In addition, the influence on the sensor output value based on the combination of the orientations of the rotors 57a and 62a should also appear in the two sensor output values X _B1 and X _A1 already acquired by measurement. Therefore, by adding the difference between the acquired sensor output values X _B1 and X _A1 to the sensor output value X _A2 that should be the same value if there is no influence of the rotors 57a and 62a, the influence of the rotors 57a and 62a is obtained. The logic is that the added sensor output value _XB2 is calculated.

More specifically, since the rotors 57a and 62a are magnetized, the rotors 57a and 62a themselves generate a magnetic field, and this magnetic field is applied to the azimuth sensor 53, thereby affecting the sensor output value _XB2 . . Further, since the rotors 57a and 62a are magnetic bodies, when an external magnetic field is applied, new magnetization is generated with a magnetic permeability μ, and a magnetic field based on the new magnetization is applied to the orientation sensor 53. The sensor output value _XB2 is affected. Therefore, the sensor output X _B2 includes a magnetic field H _OUT2 applied to the direction sensor 53 by an external magnetic field in the second direction II, a magnetic field Hb applied to the direction sensor 53 from the magnetic poles of the rotors 57a and 62a of the pattern B, The total X component “(H _OUT2 + Hb + Hμ ₂₎ of the external magnetic field in the second direction II and the magnetic field Hμ ₂ newly generated in the rotors 57a and 62a and applied to the direction sensor 53 based on the magnetic permeability μ of the rotors 57a and 62a. ) _X ”.

Similarly, the sensor output X _A2 when the external magnetic field in the second direction II is applied in the pattern A is “(H _OUT2 + Ha + Hμ ₂ ) _X ”, and the external magnetic field in the first direction I is applied in the pattern B. The sensor output X _B1 is “(H _OUT1 + Hb + Hμ ₁ ) _X ”, and the sensor output X _A1 when the external magnetic field in the first direction I is applied in the pattern A is “(H _OUT1 + Ha + Hμ ₁ ) _X ”. Become. Here, Ha is a magnetic field applied to the direction sensor 53 from the magnetic poles of the rotors 57a and 62a of the pattern A, H _OUT1 is a magnetic field applied to the direction sensor 53 by an external magnetic field in the first direction I, and Hμ ₁ is the first. This represents a magnetic field newly generated in the rotors 57a and 62a and applied to the direction sensor 53 based on the external magnetic field in the direction I and the magnetic permeability μ of the rotors 57a and 62a.

Thus, each sensor output value X _B2 , X _A2 , X _B1 , X _A1 is represented by each component of the magnetic field, and the left side and the right side of the calculation formula (1) are calculated. Can prove. The above calculation formula (1) and the like are within a range where the influence of the magnetic permeability μ of the rotors 57a and 62a is so small that the anisotropy of the magnetic permeability μ of the rotors 57a and 62a can be ignored. When the influence of the magnetic permeability μ or the anisotropy of the magnetic permeability μ cannot be ignored, an error occurs between the calculation result of the calculation formula (1) and the actual sensor output value. Therefore, in that case, the anisotropy of the magnetic permeability of the rotors 57a and 62a may be measured in advance, and this measurement result may be reflected in the calculation formula of the sensor output value.

  FIG. 5 shows a data chart representing the contents of the correction values calculated by the trimming process and stored in the correction value storage unit 45a of the EEPROM 45.

When the calculation of each sensor output value is completed and the data shown in FIGS. 4A to 4D is obtained, the CPU of the control unit 40 determines the pattern A to pattern D from these values. The correction value is obtained by the following equation.

  Here, only the calculation formula of the correction value in the case of the pattern A is shown, but when calculating the correction value of the pattern B to the pattern D, the subscript of each sensor output value is changed from “A” to each. An arithmetic expression changed to that of the pattern may be used.

  When the correction values are calculated, the CPU of the control unit 40 writes and stores these correction values in the correction value storage unit 45a of the EEPROM 45 as shown in FIG. In FIG. 5, the same symbols are written as the correction values of Pattern A to Pattern D, but the correction values of Pattern A to Pattern D are not necessarily the same value.

Of the above correction values, “a, b, c” can be understood by adding “d = (Y _A2 −Y _A4 ) / (Y _A2 −Y _A4 ) = 1” to create four symmetric terms. In addition, the difference in the sensor output value in the X direction and the difference in the sensor output value in the Y direction when external magnetic fields in opposite directions are applied are respectively normalized by a coefficient “1 / (Y _A2 −Y _A4 )”. Value. As shown in the following equation, if there is no influence of the rotors 57a and 62a, the matrix of 2 rows and 2 columns composed of the correction values “a, b, c” is used as the X direction and Y supplied from the azimuth detecting unit 54. By multiplying the sensor output value “X, Y” in the direction, the sensor output value “X1, Y1” in which the squareness error, the mounting angle error, and the sensitivity error of the direction sensor 53 are corrected can be obtained. .

Furthermore, in this embodiment, in order to remove the offset due to the magnetic fields of the rotors 57a and 62a, the correction values “XS0 and YS0” are added as shown in the following equation (5), whereby the magnetic fields of the rotors 57a and 62a. A final sensor output value “Xf, Yf” with the error corrected is obtained. The offset value of the azimuth sensor 53 caused by the magnetic fields of the rotors 57a and 62a is “X _A0 , Y _A0 ”, but this offset value also includes the squareness error, mounting angle error, and sensitivity error of the azimuth sensor 53. Therefore, as shown in the following equation (6), the offset value “X _A0 , Y _A0 ” is multiplied by the matrix composed of the correction values “a, b, c”, thereby correcting the corrected offset value “ XS0, YS0 "are obtained, and this value is used as a correction value for offset removal.

In addition, as shown in the following equation (7), the offset values “X _A0 , Y _A0 ” due to the magnetic fields of the rotors 57 a, 62 a are added to the sensor output values “X, Y” output from the azimuth detector 54. Thus, it can be considered that the corrected final sensor output value “Xf, Yf” is calculated by multiplying the matrix composed of the correction values “a, b, c”.

Therefore, when performing azimuth measurement, the corrected azimuth is calculated by performing the following calculation using the correction values “a, b, c, XS0, YS0” corresponding to the combination pattern of the rotors 57a, 62a. It is possible to find the corner.

FIG. 6 shows a table representing conditional expressions for obtaining the azimuth angle. In the calculation processing of the azimuth measurement, since the function of tan ⁻¹ is accompanied by uncertainty of a constant “π”, the condition shown in FIG. 6 depends on the sign of “Xf” and the sign of “Yf”. By adding 180 ° or 360 °, the calculation result of 0 ° to 360 ° is obtained as the measurement direction θ.

  Next, a detailed control procedure of the trimming process and the azimuth measurement process will be described with reference to a flowchart.

  In FIG. 7, the flowchart of the trimming process which CPU of the control part 40 performs is shown.

  When the trimming process is started, the CPU first outputs drive pulses to the motor drive circuits 58 and 63 and confirms the data held in the polarity storage circuits 59 and 64, and the rotors of the step motors 57 and 62 are detected. 57a and 62a are set to the state of pattern A shown in FIG. 3A (step S1).

  Next, the CPU activates the azimuth sensor 53 and the azimuth detector 54 to measure magnetism (step S2), and based on the sensor output value of the azimuth detector 54, the external magnetic field is applied by the geomagnetic simulator I (first step). It is determined whether or not an external magnetic field is applied from one direction I (step S3). At this stage, the operator applies an external magnetic field of the geomagnetic simulator I from the outside of the electronic compass 1. Thus, “YES” is determined in the determination process in step S3, and the process proceeds to the next step. Since the external magnetic field of the geomagnetic simulator I is guaranteed to be accurately applied from the outside, the CPU roughly determines whether or not a magnetic field of a certain magnitude is applied from the first direction I. It can be determined whether or not the external magnetic field of the geomagnetic simulator I is applied.

  If the geomagnetic simulator I is confirmed as a result of the discrimination process in step S3, the CPU then operates the direction sensor 53 and the direction detection unit 54 to output sensor output values in the X direction and the Y direction from the direction detection unit 54. To get. The sensor output value is stored in the RAM 47 (step S4). Subsequently, the CPU determines whether the combination pattern of the magnetic pole directions of the rotors 57a and 62a has been changed from the pattern A to the pattern D (step S5). If not yet, the CPU is shown in FIGS. 3 (a) to 3 (d). Thus, the pattern A to the pattern D are changed one by one in order (step S6), and the process returns to step 4 and the acquisition of the sensor output value and the storage in the RAM 47 are repeated.

The sensor output values “X _A1 , Y _A1 , X when the external magnetic field of the geomagnetism simulator I is applied and the rotors 57 a, 62 a are in the patterns A to D are repeated by repeating the steps S 4 to S 6. _{B1, Y B1, X C1,} Y C1, X D1, Y D1 " is acquired and stored in a predetermined area of the RAM47 as shown in FIG. 4 (a) ~ (d) .

  Of the above processes, the operation of generating the geomagnetic simulator I and the processes of steps S4 to S6 constitute the first step of the electronic compass adjustment method.

When the sensor output value is acquired, the CPU then drives the step motors 57 and 62 to return the rotors 57a and 62a to the state of the pattern A in FIG. 4A (step S7). Further, the azimuth sensor 53 and the azimuth detection unit 54 are operated to measure magnetism (step S8), and based on the sensor output value of the azimuth detection unit 54, application of an external magnetic field of the geomagnetic simulator II (second direction II) It is determined whether or not an external magnetic field has been applied (step S9). When the application of the external magnetic field is determined, sensor output values “X _A2 , Y _A2 ” in the X direction and Y direction from the azimuth detecting unit 54 are acquired and stored in the RAM 47 (step S10).

Similarly, when the external magnetic field of the geomagnetic simulator III is applied, when the geomagnetic simulator IV is applied, and when no magnetic field is applied, these confirmation processes (steps S11, S12, After passing through S14, S15, S17, S18), the sensor output values “X _A3 , Y _A3 , X _A4 , Y _A4 , X _A0 , Y _A0 ” of the azimuth detecting unit 54 are acquired and stored (S13, S16, S19) is performed. Through these processes, all the data of the white background items in FIG.

  Of the processes in steps S1 to S19, the first storage control means is configured by the process of acquiring and storing the data in FIG. 4A, and acquiring and storing the data in FIGS. 4B to 4D. The process constitutes a second storage control means.

  In addition, among the above processes, the operation of generating the geomagnetic simulators II to IV and the processes of steps S10, S13, and S16 constitute the second step of the electronic compass adjustment method.

When the necessary sensor output values have been acquired, the CPU next activates the geomagnetic simulator I in the pattern A state in order to calculate the data of the shaded items in FIGS. Sensor output values “X _A1 , Y _A1 ” and sensor output values “X _B1 , Y _B1 ”, “X _C1 , Y _C1 ” when the geomagnetic simulator I is activated in the patterns B to D, The difference from “X _D1 , Y _D1 ” is calculated (step S20). Here, the value in parentheses on the right side in the calculation formula shown in [Formula 1] is calculated in advance.

  Subsequently, using the difference between the sensor output values calculated in step S20, the sensor output values in the patterns B to D when the geomagnetic simulators II to IV are activated and when there is no external magnetic field, that is, FIG. The data of the shaded items 4 (b) to 4 (d) is calculated and written in a predetermined area of the RAM 47 (step S21). The calculation here is performed according to the above-described calculation formula of [Equation 1].

  When the sensor output values shown in FIGS. 4A to 4D are obtained, the CPU then uses these sensor output values so that the orientations of the rotors 57a and 62a correspond to the states of patterns A to D, respectively. The correction value thus calculated is calculated and stored in the correction value storage unit 45a of the EEPROM 45 as shown in FIG. 5 (step S22). The calculation of the correction value is performed according to the above formula [2].

  Of the above processing steps, the first correction value calculation means is configured by the process of calculating the correction value of pattern A in step S22, and the process of calculating the correction values of patterns B to D in steps S20 and S21 and step S22. Constitutes a second correction value calculation means. Further, the process of steps S20 to S22 constitutes a third step of the electronic azimuth meter adjustment method.

  When the correction value is saved, the trimming process is terminated.

  In FIG. 8, the flowchart of the direction measurement process performed by CPU of the control part 40 is shown.

  This azimuth measurement process is a process executed at a predetermined time interval in order to obtain the azimuth angle in the measurement direction in the azimuth meter mode. When the azimuth measurement process is started, first, the CPU of the control unit 40 operates the azimuth sensor 53 and the azimuth detection unit 54 to acquire sensor output values in the X direction and the Y direction from the azimuth detection unit 54 ( Step S31).

  Next, the CPU reads the held data from the polarity storage circuits 59 and 64, and determines which combination pattern of patterns A to D the rotors 57a and 62a of the step motors 57 and 62 are in (step S32). .

  When the sensor output value is acquired and the combination pattern of the rotors 57a and 62a is determined, the CPU subsequently proceeds from the correction value storage unit 45a of the EEPROM 45 to the correction values “a, b, c, XS0, YS0 "are read (step S33).

  Then, as shown in [Formula 5] above, the sensor output values “X, Y” are corrected using the correction values “a, b, c, XS0, YS0”, and the azimuth angle θ in the measurement direction is calculated. (Step S34: Direction calculation means). As a result, the offset error due to the magnetic fields of the rotors 57a and 62a, the squareness error of the azimuth sensor 53, the mounting angle error, and the sensitivity error between the X direction and the Y direction are corrected, and the dial 12 of the electronic azimuth meter 1 is corrected. The azimuth angle of the hour position is accurately obtained. And this azimuth | direction measurement process is complete | finished.

  As described above, according to the electronic azimuth meter 1 of this embodiment and the adjustment method of the electronic azimuth meter 1 by the trimming process, there are a plurality of step motors 57 and 62, and the magnetic pole directions of the rotors 57a and 62a. Even if there are a large number of combination patterns, the trimming process acquires sensor output values when all the geomagnetic simulators I to IV are activated for only one combination pattern, and one geomagnetic simulator for the other combination patterns. Only by acquiring the sensor output value when I is activated, the correction values in all the combined patterns of the rotors 57a and 62a can be obtained. Therefore, compared to the case where sensor output values are acquired in all states, trimming processing time can be shortened, and trimming processing can be completed within a short time even when there are a large number of the above combination patterns. it can.

  Such an effect of shortening the trimming process time is particularly useful when the trimming process is performed for each individual product in the adjustment process before product shipment.

  Further, according to the electronic azimuth meter 1 of this embodiment, a plurality of sets of correction values “a, b, c, XS0, YS0” corresponding to the patterns A to D are obtained by the trimming process and stored in the EEPROM 45. Yes. Therefore, in the azimuth measurement process, the corresponding correction value can be read from the EEPROM 45, and the sensor output value can be corrected by a calculation process with less load to obtain the azimuth angle in the measurement direction.

  Further, according to the electronic azimuth meter 1 of this embodiment, each sensor output value (see FIGS. 4A to 4D) for calculating the correction value is temporarily stored in the RAM 47 and corrected. After obtaining the value, it is in an erasable state. Therefore, the storage capacity is not unnecessarily occupied by the trimming process.

[Second Embodiment]
The electronic azimuth meter of the second embodiment is obtained by slightly changing the contents of data stored in the EEPROM 45 in the trimming process and the contents of the correction calculation performed in the azimuth measurement process from those of the first embodiment. It is. Other processes, configurations, and the like are substantially the same as those in the first embodiment, and descriptions of the same configurations are omitted.

  FIG. 9 shows a data chart representing the contents of sensor output values temporarily stored in the RAM 47 in the trimming process. FIG. 10 is a data chart showing the contents of correction values stored in the correction value storage section of the EEPROM 45. FIG. 11 shows the contents of correction values stored in the difference storage section of the EEPROM 45 in the trimming process. Each represented data chart is shown.

  In the electronic azimuth meter according to the second embodiment, the correction value storage unit shown in FIG. 10 and the difference storage unit shown in FIG. 11 are set in the EEPROM 45, and the correction value “a, b, c, XS0, YS0 "are stored, and the difference storage unit stores the difference data of the sensor output value acquired by the trimming process.

[Trimming]
Also in the trimming process of the second embodiment, external magnetic fields in the first direction I to the fourth direction IV are individually applied to the electronic azimuth meter, and the combination pattern of the magnetic pole directions of the rotors 57a and 62a is changed. The sensor output value of the azimuth detecting unit 54 in a predetermined state is acquired. The sensor output value to be acquired is the same as in the first embodiment. As shown in FIG. 9, in the state of pattern A, when external magnetic fields in the first direction I to the fourth direction IV are individually applied, and This is a sensor output value when no external magnetic field is applied, and in the state of patterns B to D, it is a sensor output value when an external magnetic field is applied from the first direction I.

  In the trimming process of the second embodiment, unlike the first embodiment, after obtaining each sensor output value, an external magnetic field in the second direction II to the fourth direction IV is applied in the state of the patterns B to D. The sensor output value at that time is not calculated.

  In the trimming process of the second embodiment, instead, the difference between the sensor output values so that the correction process can be performed on the sensor output values measured in the patterns B to D during the azimuth measurement process. (See FIG. 11) is calculated and stored in the difference storage unit.

  In the trimming process of the second embodiment, the correction values “a, b, c, XS0, YS0” corresponding to the pattern A are calculated using a plurality of sensor output values for the pattern A (see FIG. 10). These correction values are stored in the correction value storage unit.

[Direction measurement processing]
In the azimuth measurement processing of the second embodiment, the azimuth detection unit uses the correction values “a, b, c, XS0, YS0” corresponding to the pattern A shown in FIG. 10 and the difference data shown in FIG. The sensor output value of 54 is corrected to determine the azimuth angle θ in the measurement direction.

  When the orientation of the rotors 57a, 62a is pattern A, the sensor output value is corrected using the correction values “a, b, c, XS0, YS0” of the correction value storage unit, and the corrected azimuth angle in the measurement direction θ can be obtained. This is as shown in [Formula 5] of the first embodiment.

When the orientation of the rotors 57a and 62a is the pattern C, first, as shown in the following equation, the sensor output values “X _C , Y _C ” supplied from the azimuth detecting unit 54 are stored in the difference storage unit. Difference data corresponding to the pattern C is added and converted into sensor output values “X _A , Y _A ” in the state of the pseudo pattern A.

Next, using the sensor output value “X _A , Y _A ” of the pseudo pattern A and the correction values “a, b, c, XS 0, YS 0” corresponding to the pattern A, as shown in the following equation: Corrective calculation is performed to determine the corrected azimuth angle θ in the measurement direction.

It should be noted that the correction calculation corresponding to the sensor output value “X _C , Y _C ” of the pattern C (see the following formula (10); formula (7)) and the converted sensor output value of the pseudo pattern A “ The correction operation using X _A , Y _A ″ (see the following equation (11); see equation (7)) is equivalent as shown below. Conversion from the following equation (10) to equation (11) is performed from the sensor output value of pattern C to the sensor output value of pattern A using the conversion equation of [Equation 1] and the conversion equation of [Equation 6]. It is developed as is. Further, the correction values “a, b, c” and their matrices are distinguished from those corresponding to the pattern A by subscripts A and C, and those corresponding to the pattern C. The following equations (8), ( As shown in 9), these values are equivalent.

  Therefore, the azimuth angle of the measurement direction in the case of the pattern C can be accurately obtained by the calculation of the azimuth measurement using the sensor output value of the pseudo pattern A and the correction value corresponding to the pattern A.

  Next, the control procedure of the trimming process and the azimuth measurement process of the second embodiment will be described based on a flowchart.

  FIG. 12 shows a flowchart of the trimming process of the second embodiment.

  In the control procedure of the trimming process of the second embodiment, the sensor output values are acquired when the geomagnetic simulators I to IV are activated and when no magnetism is generated, with the orientations of the rotors 57a and 62a being the respective combination patterns. The processing in steps S1 to S19 is the same as in the first embodiment. Through this process, the sensor output values of FIGS. 9A to 9D are acquired and temporarily stored in the RAM 47.

  In the trimming process of the second embodiment, when the sensor output value is acquired, first, the calculation of [Equation 2] is performed based on the sensor output value of the pattern A shown in FIG. Correction values “a, b, c, XS0, YS0” are obtained. Then, this is written and stored in the correction value storage unit (FIG. 10) of the EEPROM 45 (step S40: first correction value calculation means).

  Next, the CPU of the control unit 40 uses the sensor output value when the geomagnetic simulator I shown in FIGS. 9A to 9D is activated, and the sensor output value in the pattern A state and the other pattern states. The difference from the sensor output value is obtained, and this is written and stored in the difference storage section (FIG. 11) of the EEPROM 45 (step S41: difference storage control means). The process of steps S40 and S41 constitutes the fourth step of the electronic compass adjustment method. When the correction value data and the difference data are stored, the trimming process ends.

  In FIG. 13, the flowchart of the direction measurement process of 2nd Embodiment is shown. In the second embodiment, the azimuth calculation means is configured by the CPU of the control unit 40 executing this azimuth measurement processing.

  In the azimuth measurement process of the second embodiment, the sensor measurement process of step S51 and the process of determining the combination pattern of the magnetic pole directions of the rotors 57a and 62a of step S52 are the processes of steps S31 and S32 of the first embodiment. It is the same.

After obtaining the sensor output value and determining the combination pattern of the orientations of the rotors 57a and 62a, the CPU of the control unit 40 then performs data corresponding to the combination pattern of the rotors 57a and 62a from the difference storage unit of FIG. Is read (step S53). For example, in the case of the pattern C, the difference data “X _C1 −X _A1 , Y _C1 −Y _A1 ” is read. If the pattern discrimination result in step S52 is pattern A, no difference data is required and no reading is performed.

Subsequently, the CPU of the control unit 40 adds the difference data read in step S53 to the sensor output value acquired in step S51, thereby obtaining the sensor output value “X _A , Y _A ” of the pseudo pattern A. Obtain (difference correction means). Further, using the sensor output value “X _A , Y _A ” of the pseudo pattern A and the correction value data in the correction value storage unit (FIG. 10), the calculation of [Equation 7] is performed to determine the azimuth angle in the measurement direction. θ is obtained (step S54: second azimuth calculating means). If the pattern discrimination result in step S52 is pattern A, the azimuth angle θ in the measurement direction is simply obtained using the correction value data in the correction value storage unit (FIG. 10) (first azimuth calculating means).

  By such trimming processing and azimuth measurement processing, the electronic azimuth meter according to the second embodiment can correct various errors and calculate an accurate azimuth angle θ as in the first embodiment.

  As described above, according to the electronic azimuth meter of the second embodiment and the adjustment method of the electronic azimuth meter using the trimming process, there are a plurality of step motors 57 and 62 and the rotors 57a and 62a. Even if there are a large number of combination patterns of magnetic pole orientations, sensor output values are obtained when all the geomagnetic simulators I to IV are activated for only one combination pattern in the trimming process, and one combination pattern is obtained for the other combination patterns. Only by acquiring the sensor output value when the geomagnetic simulator I is activated, correction value data and difference data necessary for the subsequent azimuth measurement processing can be obtained and stored in the EEPROM 45. Therefore, the trimming process time can be shortened, and the trimming process can be completed within a short time even if there are many combination patterns.

  Further, according to the electronic azimuth meter of the second embodiment, the correction value “a, b, c, XS0, YS0” corresponding to the pattern A in the trimming process, the sensor output value in the pattern A state, and other patterns Difference data with respect to the sensor output values in the states B to D is obtained and stored in the EEPROM 45. Therefore, the necessary storage capacity of the EEPROM 45 can be reduced as compared with that of the first embodiment. In the azimuth measurement process, the corresponding difference data and the correction value of the pattern A are read from the EEPROM 45, and the azimuth angle in the measurement direction corrected by a simple calculation can be obtained.

  Further, according to the electronic azimuth meter 1 of this embodiment, each sensor output value (see FIGS. 9A to 9D) for calculating the correction value is temporarily stored in the RAM 47 and corrected. After seeking, it is in an erasable state. Accordingly, the storage capacity of the RAM 47 is not unnecessarily occupied by the trimming process.

  The present invention is not limited to the first and second embodiments, and various modifications can be made. For example, in the first and second embodiments, the step motors 57 and 62 having two poles are applied, but those having a larger number of poles may be applied. Further, although the azimuth sensor 53 having the configuration of FIG. 2 is illustrated as the magnetic sensor, the trimming process of the present embodiment is similarly applied to any type as long as the configuration can measure magnetic fields in two intersecting directions. be able to. In addition, even if the magnetic field direction is measured by other methods, the present invention can be similarly applied as long as calibration processing can be performed based on sensor output when an external magnetic field is applied from different directions. .

  In the above embodiment, in the trimming process, an external magnetic field having the same strength is applied from four directions, and the direction sensor is calibrated from the sensor output value in each state. Applying an external magnetic field from two or three intersecting directions, or applying an external magnetic field with multiple intensities in each direction, from the sensor output value in each state The present invention can also be applied to a method of calibrating an orientation sensor.

  Further, in the above-described embodiment, the calibration process for removing the squareness error in each detection direction of the azimuth sensor, the error in the mounting angle, the sensitivity error in each detection direction, and the offset error due to the magnetic fields of the rotors 57a and 62a; The correction processing at the time of azimuth measurement for removing these errors is specifically exemplified, but the content of the error corrected by the calibration processing or the correction processing is not limited to the above error.

  In addition, the electronic azimuth meter of the present invention may not have a clock function, and is not limited to an arm-mounted type. The direction of the rotor of the step motor can also be determined by software by storing the polarity of the drive pulse output immediately before in the RAM. Further, the method for indicating the azimuth at the time of azimuth measurement is not limited to that of the above embodiment, and the details shown in the embodiment can be appropriately changed without departing from the gist of the invention.

1 Electronic compass 40 Control unit 45 EEPROM
45a Correction value storage section 46 ROM
47 RAM
53 Direction sensor MR1 to MR4 Magnetoresistive element 54 Direction detection unit 57, 62 Step motor 57a, 62a Rotor 58, 63 Motor drive circuit 59, 64 Polarity storage circuit

Claims (11)

Multiple stepper motors,
A magnetic sensor;
Polarity direction determining means for determining which combination pattern is a combination pattern of the magnetic pole directions of the plurality of rotors in the plurality of step motors among a predetermined number of combination patterns that can be taken as the combination pattern;
Correction value calculation means for calculating a plurality of azimuth calculation correction values corresponding to the predetermined number of combination patterns;
An azimuth calculating means for correcting an output value of the magnetic sensor based on the correction value for calculating the azimuth corresponding to the combination pattern determined by the polarity direction determining means, and obtaining an azimuth;
An electronic compass with
The correction value calculating means includes
Each output value of the magnetic sensor is stored in a state of a specific combination pattern that is one of the predetermined number of combination patterns and when an external magnetic field is applied separately from a plurality of predetermined directions. First storage control means;
First correction value calculation means for obtaining a correction value for calculating the azimuth for the specific combination pattern based on the output value stored by the first storage control means;
Of the predetermined number of combination patterns that can be taken as the combination pattern, an external magnetic field is applied from each of a plurality of combination patterns other than the specific combination pattern and from a first direction among the plurality of predetermined directions. Second storage control means for storing the output values of the magnetic sensor at the time,
In each state of a plurality of combination patterns other than the specific combination pattern from the output value stored by the first storage control unit and the output value stored by the second storage control unit, and in advance Calculate an output value that should be obtained from the magnetic sensor when an external magnetic field is applied from a direction other than the first direction among a plurality of determined directions, and based on these output values, other than the specific combination pattern Second correction value calculation means for respectively obtaining the azimuth calculation correction value for each of the combination patterns;
An electronic azimuth meter characterized by comprising: The first storage control means further stores the output value of the magnetic sensor in the state of the specific combination pattern and when no external magnetic field is applied,
The second correction value calculation means further calculates an output value that should be obtained from the magnetic sensor in each state of a plurality of combination patterns other than the specific combination pattern and when no external magnetic field is applied, The electronic azimuth meter according to claim 1, wherein an arithmetic operation including an output value is performed to obtain each of the azimuth calculation correction values. Comprising non-volatile storage means;
2. The electronic azimuth meter according to claim 1, wherein the correction values obtained by the first correction value calculation means and the second correction value calculation means are stored in the nonvolatile storage means. . Multiple stepper motors,
A magnetic sensor;
Polarity direction determining means for determining which combination pattern is a combination pattern of the magnetic pole directions of the plurality of rotors in the plurality of step motors among a predetermined number of combination patterns that can be taken as the combination pattern;
An azimuth calculation unit that corrects the output value of the magnetic sensor according to the combination pattern determined by the polarity direction determination unit and obtains an azimuth;
An electronic compass with
Each output value of the magnetic sensor is stored in a state of a specific combination pattern that is one of the predetermined number of combination patterns and when an external magnetic field is applied separately from a plurality of predetermined directions. First storage control means;
The magnetism when an external magnetic field is applied from a first direction among a plurality of predetermined directions in each state of a plurality of combination patterns other than the specific combination pattern among the predetermined number of combination patterns Second storage control means for storing the output values of the sensors,
First correction value calculation means for obtaining a correction value for calculating an azimuth for the specific combination pattern based on the output value stored by the first storage control means;
Difference storage control means for storing a difference between the output value stored by the first storage control means and the output value stored by the second storage control means;
With
The azimuth calculating means is
When measuring the orientation, when the orientation of the magnetic poles of the plurality of rotors is the specific combination pattern, the output value of the magnetic sensor is corrected by the correction value obtained by the first correction value calculating means to determine the orientation. First azimuth calculating means for calculating,
Difference correction means for correcting the output value of the magnetic sensor by the difference stored in the difference storage means when the direction of the magnetic poles of the plurality of rotors is a combination pattern other than the specific combination pattern when measuring the azimuth. When,
A second azimuth calculating means for correcting the output value corrected by the difference correcting means with the correction value obtained by the first correction value calculating means and calculating an azimuth;
An electronic azimuth meter characterized by comprising:   5. The electronic orientation according to claim 4, wherein the first storage control unit further stores an output value of the magnetic sensor in the state of the specific combination pattern and when no external magnetic field is applied. Total. Comprising non-volatile storage means;
5. The non-volatile storage unit stores the correction value obtained by the first correction value calculation unit and the difference stored by the difference storage control unit. Electronic compass. A working storage means for temporarily storing data;
5. The first storage control unit and the second storage control unit are configured to temporarily store output values of the magnetic sensor in the work storage unit. The electronic compass as described.   5. The electronic azimuth meter according to claim 1, wherein the step motor has a configuration in which the stator has two poles and the rotor has two poles. In the adjustment method which performs adjustment for direction measurement to the electronic direction meter according to claim 3,
An external magnetic field is applied from the first direction among the plurality of predetermined directions to the electronic azimuth meter, and the combination pattern of the magnetic pole directions of the plurality of rotors is switched to all combination patterns. In the meantime, a first step of temporarily storing the output value of the magnetic sensor by the first storage control means and the second storage control means;
An external magnetic field is applied separately from each of the plurality of predetermined directions except the first direction to the electronic azimuth meter, and a combination pattern of magnetic pole directions of the plurality of rotors Is fixed to the specific combination pattern, and in the meantime, the first storage control means temporarily stores the output value of the magnetic sensor;
After the first step and the second step, the first correction value calculation means and the second correction value calculation means are used to output a plurality of combinations corresponding to all combination patterns of the magnetic pole directions of the plurality of rotors. A third step of calculating a correction value and storing it in the non-volatile storage means;
A method for adjusting an electronic azimuth meter, comprising: In the adjustment method which performs adjustment for direction measurement about the electronic direction meter according to claim 6,
An external magnetic field is applied from the first direction among the plurality of predetermined directions to the electronic azimuth meter, and the combination pattern of the magnetic pole directions of the plurality of rotors is switched to all combination patterns. In the meantime, a first step of temporarily storing the output value of the magnetic sensor by the first storage control means and the second storage control means;
An external magnetic field is applied separately from each of the plurality of predetermined directions except the first direction to the electronic azimuth meter, and a combination pattern of magnetic pole directions of the plurality of rotors Is fixed to the specific combination pattern, and in the meantime, the first storage control means temporarily stores the output value of the magnetic sensor;
After the first step and the second step, the first correction value calculation means calculates a correction value corresponding to the specific combination pattern of the magnetic pole directions of the plurality of rotors, and the correction value, A fourth step of storing the difference to be stored by the difference storage control means in the nonvolatile storage means;
A method for adjusting an electronic azimuth meter, comprising: An assembly process for assembling an electronic compass;
An adjustment step of adjusting by the adjustment method of the electronic compass according to claim 9 or 10,
The manufacturing method of the electronic azimuth | direction meter characterized by including.

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