JP2000111348A - Zero point output correction equipment of angular velocity detecting means for moving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cope with individual difference and secular change of an angular velocity sensor, concerning zero point voltage-temperature characteristic of the angular velocity sensor. SOLUTION: An azimuth angle operating apparatus 10 as this equipment is installed in navigation equipment of an automobile, and detects an azimuth angle of the automobile, on the basis of the output of an angular velocity sensor 11. Zero point voltage-temperature characteristic of the angular velocity sensor 11 is written erasably in a correction characteristic storing memory 17. When a moving body velocity judging means 24 and a GPS system 26 detect the time when the angular velocity sensor 11 during straight running or the like outputs a zero point voltage, a temperature sensor 14 detects the environmental temperature of the angular velocity sensor 11 together with the output voltage of the angular velocity sensor 11. A zero point voltage of the zero point voltage- temperature characteristic in the correction characteristic storing memory 17 at the detected temperature is changed to the detected output voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zero-point output correcting device for an angular velocity detecting means used as an element of a navigation device or the like in a moving body such as an automobile or a ship, and more particularly to a zero point based on the temperature of the angular velocity detecting means for a moving body. The present invention relates to a zero-point output correction device having an output correction function.

[0002]

2. Description of the Related Art When autonomous navigation is performed by mounting a navigation device on a moving body such as a vehicle or a ship, it is necessary to periodically detect the azimuth or the amount of change in azimuth of the moving body. Generally,
As the angular velocity sensor, a gyro sensor is used to detect the angular velocity and integrate over time to obtain the azimuth change amount. There are various types of gyro sensors, such as a vibration type, a rotation type, a gas rate type, and an optical fiber type, and the vibration type is mainly used for autonomous navigation. Vibrating gyro sensors detect angular velocity using the Coriolis force generated in the direction perpendicular to the direction of vibration when a rotating angular velocity is applied to a vibrating object.It is inexpensive, compact, and suitable for mass production. (For example, manufactured by Murata,
An equilateral triangular vibration gyro. (See "Electronic Life", October 1994 issue, pages 30 to 36, published by the Japan Broadcasting Corporation).

As shown in FIG. 2, various gyro sensors such as a vibrating gyro sensor usually output a voltage that changes almost linearly with respect to an input angular velocity within a certain range. The output voltage of the sensor is input to the position calculation microcomputer via the A / D converter. The position calculation microcomputer obtains angular velocity data by performing a predetermined conversion on the sensor output, and further obtains azimuth change data by performing time integration.
Then, the position is obtained by vector calculation separately from the distance data input from the distance sensor.

In FIG. 2, the output voltage of the angular velocity detecting means when the input angular velocity is zero is generally referred to as a zero point voltage. In this specification, "zero point voltage" means the above contents. In addition, the case where the input angular velocity is zero is not only a case where the moving body itself is stopped (hereinafter referred to as a “stop state”), but also a state where the moving body is traveling straight (hereinafter “the straight traveling state”). ). However, in a state where the moving body is rotating at a constant angular velocity (hereinafter, referred to as a “rotation state”), the output voltage does not necessarily output the zero point voltage but outputs a constant value. In the present specification, when the input angular velocity is constant, the output voltage does not fluctuate. Therefore, the stopped state, the straight traveling state, and the rotating state are collectively defined as a “stationary state”.

[0005]

By the way, in a moving body such as a vehicle and a ship, the temperature changes drastically. On the other hand, the zero point voltage has a temperature characteristic that fluctuates depending on the temperature, and also has a characteristic that fluctuates over time. Unless it is grasped and the angular velocity is not determined to be exactly zero, errors in the angular velocity sensor accumulate in autonomous navigation, resulting in a large position error.

Further, as shown in FIGS. 4A to 4C, since the temperature characteristics of the zero point voltage of the angular velocity sensor vary depending on individual differences, the zero point voltage of the angular velocity sensor mass-produced as the same kind of angular velocity sensor is used. Even if the temperature characteristics are as shown in FIG. 3, it is necessary to make appropriate corrections individually.

In order to avoid this, Japanese Patent Application Laid-Open No. Hei 6-160100 discloses a method for correcting the temperature characteristic of the zero point voltage by using a temperature sensor for each angular velocity sensor. According to this, the zero point voltage temperature characteristic and the sensitivity temperature characteristic are measured in advance while setting the environmental temperature change using a personal computer, the temperature characteristic data is stored in a memory such as an EEPROM, and adjustment is performed using a predetermined calculation formula. A signal processing circuit for a vibrating gyro is disclosed, which describes that sensitivity adjustment, zero-point voltage temperature correction, and sensitivity temperature correction of a gyro sensor can be performed efficiently and completely.

However, according to this type of processing circuit, the temperature characteristic is individually measured in accordance with the variation of the temperature characteristic of the zero point voltage of the vibrating gyroscope due to the individual difference, and the inherent characteristic of the vibrating gyroscope is previously determined using a personal computer. It is difficult to apply the method to mass-produced products, for example, since it is necessary to individually store the characteristics in the memory, and it is necessary to perform the measurement again when the angular velocity sensor is replaced.

An object of the present invention is to provide a zero-point output correction device for an angular velocity detecting means for a moving object which overcomes the above-mentioned problems.

[0010]

According to the present invention, the moving object angular velocity detecting means (11) is mounted on the moving object, and the time integral of the output is used for calculating the azimuth change amount of the moving object. It has become. The zero point output correction device (10) of the moving object angular velocity detecting means (11) has the following (a) to (d). (A) moving body direction determining means (32) for determining whether or not the direction of the moving body is maintained substantially constant; (b) temperature detecting means (14) (c) for detecting the temperature of the angular velocity detecting means (11) ) The output of the angular velocity detecting means (11) when the direction of the moving body is maintained substantially constant is defined as the zero point output, and the relationship between the zero point output of the angular velocity detecting means (11) and each temperature is defined as a zero point output-temperature characteristic. Zero point output-temperature characteristic storage means to be stored
(17) (d) If the moving body direction determining means (32) determines that the direction of the moving body is maintained substantially constant, the zero point output is obtained.
The zero-point output-temperature of the zero-point output-temperature characteristic of the temperature characteristic storage means (17) at the current detected temperature of the temperature detecting means (14) is corrected based on the current output of the angular velocity detecting means (11). Characteristic modification means (30)

According to the zero point output correcting device (10) of the angular velocity detecting means (11) for a moving body of the present invention, the angular velocity detecting means (11)
Is provided with an angular velocity sensor (11) that directly detects the angular velocity acting on the moving body, or an angular acceleration detection sensor that detects the angular acceleration acting on the moving body, and a time integrated value of the output of the angular acceleration detection sensor. And integrating means for outputting the angular velocity. That is, the moving object angular velocity detecting means (11) of the present invention may be an angular velocity sensor (11) alone, or may be a combination of an angular acceleration detecting sensor and an integrating means for integrating the output thereof over time.

The moving objects include not only automobiles but also other moving objects such as ships. The angular velocity detecting means (11) is usually used for a navigation device or the like mounted on a moving body. Temperature of angular velocity detecting means (11) itself and angular velocity detecting means
The temperature of the angular velocity detecting means (11) detected by the temperature detecting means (14) is substantially equal to the ambient temperature of (11).
(11) It includes the temperature of itself and the ambient temperature of the angular velocity detecting means (11). The zero point output of the angular velocity detecting means (11) means that the angular velocity detecting means (11) outputs when the angular velocity = 0.
The output of the angular velocity detecting means (11) includes a voltage output type, a current output type, an impedance output type, and the like.Therefore, the zero point output of the angular velocity detecting means (11) includes not only the zero point voltage but also the zero point current, It also includes zero impedance and zero resistance.

The zero-point output-temperature characteristics of the zero-point output include not only individual differences in the zero-point output but also changes with time and aging. Zero point output correction device (10) of this moving object angular velocity detection means (11)
In the case, when the moving body direction determining means (32) determines that the direction of the moving body is maintained substantially constant, that is, when it is determined that the angular velocity detecting means (11) outputs the zero point output, The zero point output of the temperature detecting means (14) at the current detected temperature of the zero point output-temperature characteristic of the zero point output-temperature characteristic storing means (17) is corrected based on the current output of the angular velocity detecting means (11) ( Generally, the output is changed to the output of the angular velocity detecting means (11) at that time.) The detected temperature of the angular velocity detecting means (11) when the moving body direction determining means (32) determines that the direction of the moving body is maintained substantially constant is not always the same but appropriately different. As a result, the zero-point output at various temperatures of the zero-point output-temperature characteristic of the zero-point output-temperature characteristic storage means (17) is corrected. In this way, the zero point output-temperature characteristics caused by the individual difference of the zero point output and the aging and aging are corrected based on the individual angular velocity detecting means (11) and based on the aging and the aging. The azimuth change amount of the moving object can be detected from the output of the angular velocity detecting means (11) based on the correct zero point output-temperature characteristic.

According to the zero point output correction device (10) of the moving object angular velocity detecting means (11) of the present invention, the zero point output and the zero point of the temperature characteristic storage means (17) by the temperature characteristic correcting means (30) are provided. The correction of the output-temperature characteristic includes not only the zero-point output of the zero-point output-temperature characteristic of the zero-point output-temperature characteristic storage means (17) at the temperature detected by the temperature detecting means (14) but also the detected temperature at that time. The zero point output and the zero point output of the temperature characteristic of the temperature characteristic storage means (17) at other temperatures within the temperature range included in the above are also performed based on the output of the angular velocity detecting means (11) at that time.

When the moving body direction determining means (32) determines that the direction of the moving body is maintained substantially constant, the detected temperature of the angular velocity detecting means (11) at that time is, although there are some, the zero point output is obtained. The temperature characteristic is limited over the entire temperature; On the other hand, the zero point output of the temperature characteristic near the detected temperature at that time is estimated to be a value close to the output of the angular velocity detecting means (11) at that time. Therefore, even if it is not the detected temperature at that time, each zero-point output of the zero-point output-temperature characteristic within the temperature range including the detected temperature at that time is expressed as
By correcting based on the output of the angular velocity detecting means (11) at that time, the zero point output at each temperature of the zero point output-temperature characteristic of the zero point output-temperature characteristic storage means (17) can be efficiently corrected.

According to the zero point output correction device (10) of the moving object angular velocity detecting means (11) of the present invention, the moving object is detected at the mutually different first and second temperatures detected by the temperature detecting means (14). The moving body direction determining means (32) determines that the direction is maintained substantially constant, and the angular velocity detecting means (1
Assuming that the output of 1) is a first output and a second output, respectively, the zero-point output-temperature characteristic of the zero-point output-temperature characteristic storage means (17) is
The zero point output at each temperature between the first and second temperatures is corrected based on the first and second outputs.

When the moving body orientation determining means (32) determines that the direction of the moving body is maintained substantially constant, the detected temperature of the angular velocity detecting means (11) at that time is zero point output although there are some. The temperature characteristic is limited over the entire temperature; When the moving body direction determining means (32) determines that the direction of the moving body is maintained substantially constant at the first and second temperatures, the zero point output at each temperature between the first and second temperatures is obtained. The zero point output of the temperature characteristic storage means (17); the zero point output of the temperature characteristic is corrected based on the first and second outputs, whereby the zero point output-temperature characteristic storage means (1
The zero-point output at each temperature of the zero-point output-temperature characteristic of 7) can be efficiently corrected. Note that the zero point output and the zero point output of the temperature characteristic of the temperature characteristic storage means (17) at each temperature between the first and second temperatures are as follows.
For example, an interpolation method or the like is used as a method of correcting based on the second output. The interpolation method includes not only a case where two discrete outputs of the angular velocity detecting means (11) are connected by a straight line and each value on the straight line is used as a zero point output, but also Three outputs are connected by an appropriate quadratic curve,
The case where each value on the quadratic curve is used as the zero point output is also included.

According to the moving object angular velocity detecting means (11) of the present invention, the moving object direction judging means (32) detects that the moving object is substantially straight ahead while the moving object is traveling and the history of the current position by the GPS. When it is determined that the moving object is present, it is determined that the moving direction of the moving body is maintained substantially constant.

The current position of the moving body at each time is determined by the GPS positioning, and the movement locus of the moving body can be determined from the change in the current position. If the trajectory is a straight line for a predetermined time,
It is determined that the moving object is going straight. When the moving body is traveling straight, the output of the angular velocity detecting means (11) is a zero-point output, so the zero-point output-temperature characteristic of the zero-point output-temperature characteristic storing means (17) is converted to the angular velocity detecting means (11). Can be modified by the current output of

According to the moving object angular velocity detecting means (11) of the present invention, the moving object direction judging means (32) determines that the vehicle speed of the automobile is zero.
And the output of the angular velocity detecting means (11) is zero point output-
If the difference between the zero-point output of the temperature characteristic storage means (17) and the zero-point output at the temperature detected at that time by the temperature detection means (14) is within a predetermined range, the direction of the moving body becomes substantially constant. It is determined that it is maintained.

Even if the moving object is in the stationary state as defined above, it is not limited to the stopped state. For example, there is a case where a car is mounted on a turntable in a parking lot and is rotating. In such a case, if the zero-point output-temperature characteristic of the zero-point output-temperature characteristic storage means (17) is corrected, the zero-point output-temperature characteristic becomes incorrect. When the moving body is rotating, the angular velocity detecting means (1
The output of (1) is significantly different from the zero output at the temperature detected by the temperature detecting means (14) in the zero output-temperature characteristic of the zero output-temperature characteristic storing means (17). Therefore,
If the output of the angular velocity detecting means (11) greatly deviates from the zero point output-temperature characteristic storage means (17) zero point output-temperature characteristic of the temperature detecting means (14) at the detected temperature at that time, That is, if the difference exceeds the predetermined value, the moving body is determined to be in a rotating state that is not a stopped state even if the vehicle speed is 0 and the vehicle is stationary, and the zero point output-temperature characteristic storage means (17)
The correction of the zero point output-temperature characteristic of is stopped. Conversely, if the difference is within the predetermined value, the moving body maintains the orientation constant,
It is determined that the motor is stopped, and the zero-point output-temperature characteristic of the zero-point output-temperature characteristic storage means (17) is corrected based on the current output of the angular velocity detection means (11).

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of the azimuth calculating device 10. The azimuth calculation device 10 forms a part of a navigation device mounted on an automobile. The angular velocity sensor 11 is composed of, for example, a vibrating gyroscope, and detects the angular velocity of the vehicle around a vertical line. The output voltage of the angular velocity sensor 11 is A / D-converted by the A / D converter 12 and input to the calculating means 13. The temperature sensor 14 is an angular velocity sensor 11
, And detects the ambient temperature of the angular velocity sensor 11. It is considered that the ambient temperature of the angular velocity sensor 11 is substantially equal to the temperature of the angular velocity sensor 11. The output voltage of the temperature sensor 14 is A / D-converted by an A / D converter 15 and is calculated by an arithmetic unit.
Entered into 13. The ROM 16 is written with default values of zero-point voltage-temperature characteristics (for example, FIG. 3). The correction characteristic storage memory 17 is readable and writable, and retains its memory even when the power of the azimuth calculating device 10 is turned off by the power from the backup power supply or for a non-volatile type. When the power is turned on for the first time, the default value from the ROM 16 is written as the initial value of the zero-point voltage-temperature characteristic, and then the zero-point voltage-temperature characteristic is appropriately corrected as described later. The calculation means 13 has a position calculation microcomputer 18 for calculating the azimuth (= direction) of the automobile, and an internal memory 19 which is used for calculation processing of the position calculation microcomputer 18 and which can read and write data. In the calculation of the azimuth of the vehicle by the position calculation microcomputer 18, for example, the output from the angular velocity sensor 11 is integrated over time to calculate the azimuth change amount with respect to the absolute azimuth, and this is used as the azimuth.

The moving body speed judging means 24 is equipped with a vehicle speed sensor 25 which outputs a pulse in synchronization with the rotation of the tire of the vehicle, and counts the number of output pulses of the vehicle speed sensor 25 within a predetermined time, thereby The vehicle speed of the vehicle. The GPS system 26 has a GPS receiver 27 and a detector 28 that detects the current position of the vehicle from the output of the GPS receiver 27 and detects whether the vehicle is traveling straight from a change in the current position. . The offset checking means 30 corrects the zero-point voltage-temperature characteristic of the correction characteristic storing memory 17 based on the input from the stationary state determining means 32. The error determination means 31
The output voltage data of the angular velocity sensor 11 is input via the / D converter 12, the data relating to the zero-point voltage-temperature characteristic of the correction characteristic storage memory 17 via the offset checking means 30, and the temperature sensor from the arithmetic means 13. Various data such as 14 output voltage data are input and the correction characteristic storage memory
A determination is made as to whether or not the difference between the zero-point voltage of the temperature sensor 14 at the current detection temperature of the zero-point voltage-temperature characteristic 17 and the current output voltage of the angular velocity sensor 11 is within a predetermined value.
The stationary state determination unit 32 includes a moving body speed determination unit 24, a detector
28, and based on the input from the error determining means 31, it is determined whether the vehicle is in a stationary state (including a straight running state, a stopped state, and a rotating state as already defined), and the determination is Yes. At some point, the fact is output to the offset checking means 30.

FIG. 2 shows an output voltage characteristic of the angular velocity sensor 11 at a predetermined temperature. The angular velocity sensor 11 generates an output voltage related to the angular velocity acting on the angular velocity sensor, that is, the angular velocity ω around a predetermined vertical line of the vehicle on which the angular velocity sensor 11 is mounted. The output voltage of the angular velocity sensor 11 when ω = 0 is defined as a zero point voltage. In this output voltage characteristic, the angular velocity to the right of the automobile is positive, and the angular velocity to the left is negative. The output voltage of the angular velocity sensor 11 is ω =
Within a predetermined range around 0, the value changes along a straight line falling to the right with respect to ω, and outside the predetermined range, it takes a predetermined value of − or +.

FIG. 3 shows a standard zero point voltage of the angular velocity sensor 11.
It is a temperature characteristic. The zero point voltage increases linearly with increasing temperature.

FIG. 4 shows various zero point voltage-temperature characteristics depending on the individual difference of the angular velocity sensor 11. 4A to 4C, the dotted lines indicate the standard zero-point voltage-temperature characteristics of FIG. In FIG. 4A, the zero-point voltage matches the standard zero-point voltage-temperature characteristic when the temperature is lower than the predetermined temperature, and the slope (the amount of increase in the zero-point voltage / the amount of temperature increase) has the standard zero-point voltage-temperature characteristic when the temperature is equal to or higher than the predetermined temperature. Is greater than the slope of FIG.
In (b), the zero-point voltage matches the standard zero-point voltage-temperature characteristic below the predetermined temperature, and the gradient is smaller than the standard zero-point voltage-temperature characteristic above the predetermined temperature. The zero-point voltage-temperature characteristic in FIG. 4C is bent at a predetermined temperature, and the zero-point voltage is higher than the standard zero-point voltage-temperature characteristic below the predetermined temperature, and the standard zero-point voltage-temperature characteristic above the predetermined temperature. It is lower.

FIG. 5 shows the zero-point voltage of the correction characteristic storage memory 17.
9 is a flowchart of a program for initially setting a temperature characteristic. This process is performed when the power of the azimuth calculation device 10 is turned on for the first time and when the contents of the correction characteristic storage memory 17 are reset. The ROM 16 stores the individual angular velocity sensors 11
Is recorded regardless of the zero-point voltage-temperature characteristic (= zero-point voltage-temperature characteristic shown in FIG. 3). When the power of the azimuth calculating device 10 is turned on for the first time or the recorded contents of the correction characteristic storage memory 17 are reset, the RO
The standard zero-point voltage-temperature characteristic recorded in M16 is copied to the correction characteristic storage memory 17, and is used as the initial value of the zero-point voltage-temperature characteristic for the angular velocity sensor 11 in the correction characteristic storage memory 17.

FIG. 6 is a flowchart of an azimuth calculation program for an automobile by the azimuth calculation device 10. In S44, it is determined whether or not the azimuth angle calculation device 10 is powered on.
If es, the process proceeds to S45, and if No, the program ends. In S45, the outputs of the angular velocity sensor 11 and the temperature sensor 14 converted into digital values by the A / D converters 12 and 15 are calculated by the arithmetic means 13 and the offset check means.
Enter 30. In S46, the zero-point voltage-temperature characteristic stored in the correction characteristic storage memory 17 is input to the calculating means 13 and recorded in the internal memory 19. Correction characteristic storage memory 17
By means of the zero point voltage-temperature characteristic storage means (17), the calculating means 13 causes the position calculation microcomputer 18 to calculate the angular velocity of the angular velocity sensor 11 corresponding to the temperature detected by the temperature sensor 14.
Output voltage characteristics (eg, FIG. 2) can be created as appropriate. S4
In step 7, the position calculation microcomputer 18 obtains an angular velocity from the output voltage of the temperature detected by the temperature sensor 14 of the angular velocity-output voltage characteristic of the angular velocity sensor 11, obtains the azimuth change amount by performing time integration thereof, The azimuth change amount with respect to the azimuth is output as the azimuth angle of the vehicle. In S48, it is determined whether or not the azimuth calculating device 10 has been turned off.
If es, terminate the program; if No, terminate the program
It returns to S45.

FIG. 7 is a flowchart of the process of correcting the zero-point voltage-temperature characteristic in the correction characteristic storage memory 17. First, when the azimuth calculating device 10 is turned on (S5).
1) The error determination means 31 determines whether the data (angular velocity voltage data) of the angular velocity sensor 11 digitized by the A / D converter 12 is within a predetermined error range with respect to a predetermined reference value. (S52). If the angular velocity voltage data fluctuates beyond the predetermined error range, S52 is maintained. If the angular velocity voltage data maintains a constant value within the predetermined error range, that is, if it stays at a small fluctuation, the process proceeds to S53. Next, it is determined whether or not the angular velocity voltage data has maintained a constant value and the fluctuation has continued a minute fluctuation state within a predetermined range for a predetermined time (S53).
Returning to S52, if the predetermined time has elapsed, the process proceeds to S54. In S54, the moving body speed determining means 24 determines whether or not there is a vehicle speed pulse based on a signal from the vehicle speed sensor 25, for example. If the vehicle is not in a stopped state, the process proceeds to S55, while if a signal that indicates that the vehicle is in a stopped state is received, the process proceeds to S59. When it is determined by the detector 28 connected to the GPS receiver 27 that the moving body is going straight (S55), the stationary state determining means 32 determines whether the moving body is in the stationary state (in this case, the straight traveling state in the stationary state). ), And issues a data rewriting command to the offset checking means 30 (S56). Then, the offset checking means 30 determines the zero point voltage of the temperature for the angular velocity voltage data and the temperature voltage data transferred from the calculating means 13. The meaning data is transferred and stored in the correction characteristic storage memory 17 (S57). As a result, the zero-point voltage of the temperature in the zero-point voltage-temperature characteristic in the correction characteristic storage memory 17 is rewritten to the angular velocity voltage at that time. On the other hand, if the mobile unit is in the stopped state in S54 or if it is unknown in S55 whether the GPS system 26 is unable to perform positioning and is moving straight ahead, the offset check means 30 reads the zero point of the current temperature from the correction characteristic storage memory 17. The voltage data is read (S59). If the voltage value is different from the angular velocity voltage data transferred from the calculating means 13 by a predetermined value or more, it is determined to be “abnormal” and the data is not rewritten. Is determined to be in the stationary state (in this case, the stopped state in the stationary state), and the process proceeds to S56 (S60). S59 and S
The process of 60 is a process for preventing the value of the angular velocity sensor from being judged as zero point data in the case of a rotating state, for example, when the car is not traveling, but enters a turntable type parking lot. is there. In S58, it is determined whether or not the process is in an end state based on whether the power of the azimuth angle calculation device 10 is off or on. If the determination is Yes, the process ends. If the determination is No, the process returns to S52.

FIG. 8 shows the transition of the zero-point voltage-temperature characteristic held by the correction characteristic storage memory 17 by a total of three rewrites. In the initial state, the default zero-point voltage-temperature characteristic from the ROM 16 is set as the zero-point voltage-temperature characteristic held by the correction characteristic storage memory 17 as shown in FIG. The output voltage of the angular velocity sensor 11 and the temperature of the angular velocity sensor 11 when the first stationary condition is satisfied are represented by V1 and T, respectively.
If it is set to 1, the zero point voltage at T1 is changed to V1 in the first rewriting. Further, the zero point voltage T in a predetermined temperature range centered on T1 is also changed to a value up to that point (this is referred to as Va) and a value Vb intermediate between V1 and Va. Vb is closer to V1 as T is closer to T1, and closer to the original Va as T is farther from Vb. In this way,
By the first rewriting, the zero-point voltage-temperature characteristics of the correction characteristic storage memory 17 become as shown in FIG. Similarly,
When the second and third standstill conditions are satisfied, the zero-point voltage-temperature characteristics of the correction characteristic storage memory 17 are changed as shown in FIGS.
It is changed as shown in (c). In this way, at each temperature appropriately distributed in the zero-point voltage-temperature characteristic, the stationary condition is satisfied, and the zero-point voltage-temperature characteristic of the correction characteristic storage memory 17 is different from the initial one over the wide temperature range. The sensor 11 is gradually corrected to a unique one, which reflects a temporal change or a secular change.

FIG. 9 is a flowchart of a process of correcting the zero-point voltage-temperature characteristic in the correction characteristic storage memory 17, which is different from FIG. In S66, it is determined whether the azimuth angle calculation device 10 is powered on. If the determination is Yes, the process proceeds to S67,
If No, the correction process ends. In S67,
It is determined from the output of the vehicle speed sensor 25 whether there is a vehicle speed pulse, that is, whether the vehicle is running or stopped. If the vehicle is running, the process proceeds to S68, and if the vehicle is stopped, the process proceeds to S76.
In S68, the current traveling direction of the automobile is detected by comparing the current GPS data (current position) with the previous GPS data (for example, one second before). In S69, it is determined whether or not the angle of the traveling direction of the vehicle with respect to the absolute azimuth is the same as the current one and the previous one, that is, whether or not the vehicle is going straight ahead. Then, if No, the process proceeds to S74. In S70, the difference between the previous time and the present time is determined for the angular velocity voltage as the output voltage of the angular velocity sensor 11, and the difference is determined. In S71, it is determined whether the difference is within a certain range, that is, whether it is a small fluctuation. If the determination is Yes, the process proceeds to S74, and
If so, the process proceeds to S72. The process proceeds to S74 only when the angular velocity voltage is minutely vibrated, in order to avoid an error in rewriting the zero point voltage-temperature characteristic when the angular velocity voltage is largely fluctuated. In S72,
Current angular velocity voltage data, temperature voltage data, and GPS
The angle data is saved, and the process returns to S66. In S74, S
At 72, it is determined whether or not the stored data exists.
If es, the process proceeds to S75, and if No, the process returns to S66. In S75, the zero point voltage of the correction characteristic storage memory 17 is subtracted.
The zero-point voltage of the temperature characteristic at the temperature detected by the temperature sensor 14 at that time (= current temperature voltage data) is calculated by an angular velocity sensor.
Rewrite the output voltage at 11 (= current angular velocity voltage data) at that time. At this time, the zero point voltage−
As described with reference to FIG. 8, the zero-point voltage of the temperature characteristic is obtained by calculating the zero-point voltage-temperature characteristic of the temperature sensor 14 in the correction characteristic storage memory 17.
Not only the zero point voltage of the detected temperature at that time, but also each zero point voltage over a predetermined temperature range including the detected temperature is changed based on the output voltage of the angular velocity sensor 11 at that time. After S75, the process returns to S66. In S76, the angular velocity voltage as the output voltage of the angular velocity sensor 11 is compared between the previous time and the present time, and the difference is obtained. In S77, it is determined whether the difference is within a certain range, that is, whether it is a small fluctuation. If the determination is Yes, the process proceeds to S74. If the determination is No, the process proceeds to S66.
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[Brief description of the drawings]

FIG. 1 is a block diagram of an azimuth calculating device.

FIG. 2 is a diagram illustrating output voltage characteristics of an angular velocity sensor at a predetermined temperature.

FIG. 3 is a standard zero point voltage-temperature characteristic of the angular velocity sensor.

FIG. 4 shows various zero-point voltages depending on individual differences of angular velocity sensors.
It is a figure which shows a temperature characteristic.

FIG. 5 is a flowchart of a program for initial setting a zero-point voltage-temperature characteristic of a correction characteristic storage memory.

FIG. 6 is a flowchart of a vehicle azimuth calculation program by the azimuth calculation device.

FIG. 7 is a flowchart of a process of correcting a zero-point voltage-temperature characteristic in a correction characteristic storage memory.

FIG. 8 is a diagram showing the transition of the zero-point voltage-temperature characteristic held by the correction characteristic storage memory by a total of three rewrites.

FIG. 9 is a flowchart of another correction process.

[Explanation of symbols]

Reference Signs List 10 azimuth angle calculation device (zero point output correction device) 11 angular velocity sensor (moving object angular velocity detection means, angular velocity detection means) 14 temperature sensor (temperature detection means) 17 correction characteristic storage memory (zero point voltage-temperature characteristic storage means) 30 offset Checking means (zero point voltage-temperature characteristic correction means)

Claims (6)

[Claims] 1. A zero-point output correction device (1) of a moving object angular velocity detecting means (11) which is mounted on a moving object and whose output time integral is used for calculating an amount of change in azimuth of the moving object.
0), (a) a moving body direction determining means (32) for determining whether or not the direction of the moving body is maintained substantially constant;
(B) a temperature detecting means (14) for detecting a temperature of the angular velocity detecting means (11); (c) an output of the angular velocity detecting means (11) when the direction of the moving body is maintained substantially constant; Zero point output-temperature characteristic storage means (17) for storing the relationship between the zero point output of the angular velocity detecting means (11) and each temperature as a zero point output as a zero point output-temperature characteristic, and (d) the moving body direction determination means. When it is determined by (32) that the orientation of the moving body is maintained substantially constant, the zero point output-temperature characteristic of the zero point output-temperature characteristic storage means (17) is used for the temperature detection means (14). A zero point output-temperature characteristic correcting means (30) for correcting the zero point output at the detected temperature at that time based on the output of the angular velocity detecting means (11) at that time; Zero point output correction device of the detection means. 2. The angular velocity detecting means (11) includes an angular velocity sensor (11) for directly detecting an angular velocity acting on the moving body, or an angular acceleration detecting sensor for detecting an angular acceleration acting on the moving body. 2. A zero-point output correction device for an angular velocity detecting means for a mobile object according to claim 1, further comprising: an integrating means for outputting a value obtained by time-integrating the output of said angular acceleration detecting sensor as an angular velocity. . 3. The zero point output by the zero point output-temperature characteristic correction means (30) -the zero point output of the temperature characteristic storage means (17).
The correction of the temperature characteristic is performed by the zero point output-temperature characteristic storage means (1
7) Zero-point output-temperature characteristic, not only the zero-point output at the current detected temperature of the temperature detecting means (14), but also the zero-point output-temperature at other temperatures within the temperature range including the detected temperature at that time. 3. The zero point output of the characteristic storage means (17) and the zero point output of the temperature characteristic are also performed based on the output of the angular velocity detecting means (11) at that time.
A zero-point output correction device for a moving object angular velocity detecting means as described in the above. 4. The moving body direction determining means (3) when the direction of the moving body is maintained substantially constant at the mutually different first and second temperatures detected by the temperature detecting means (14).
2), and the angular velocity detecting means (1
Assuming that the outputs of 1) are the first and second outputs, respectively, the zero-point output at each temperature between the first and second temperatures of the zero-point output-temperature characteristic of the zero-point output-temperature characteristic storage means (17). 4. The zero-point output correcting device for an angular velocity detecting means for a moving body according to claim 1, wherein the correction is performed based on the first and second outputs. 5. The moving body orientation determining means (32) moves the moving body when it is determined that the moving body is substantially traveling straight while the moving body is traveling and the history of the current position by GPS is used. 5. The zero point output correction device for an angular velocity detecting means for a moving body according to claim 1, wherein it is determined that the direction is maintained substantially constant. 6. The moving body orientation judging means (32) outputs a zero point output from the zero point output-temperature characteristic storage means (17) when the vehicle speed of the automobile is 0 and the output of the angular velocity detecting means (11) is −
If the temperature characteristic is within a predetermined range with respect to the zero point output at the temperature detected at that time by the temperature detecting means (14), it is determined that the direction of the moving body is maintained substantially constant. 6. The zero point output correction device for angular velocity detecting means for a moving body according to claim 1, wherein: