JPH07280584A - Hybrid sensor - Google Patents

Abstract

(57) [Summary] To provide a highly convenient hybrid sensor with excellent detection accuracy and reliability. [Structure] An angular velocity sensor 2, an acceleration sensor 3, a sensor data storage unit 5, a variable calculation unit 6, a sensor correction unit 4 including a real angular velocity calculation unit 7 and a control unit 8 and an azimuth angle calculation unit 9, and an angular velocity. The sensitivity coefficient drift and offset drift of the sensor 2 and the offset drift of the acceleration sensor 3 are provided in the angular velocity signal ω _S from the angular velocity sensor 2, the acceleration signal α _S from the acceleration sensor 3, and the moving body (for example, vehicle). A hybrid sensor 1 that corrects based on a vehicle speed signal v from an external vehicle speed sensor 10 to detect the actual angular velocity ω _SN and the actual acceleration α _SN .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid sensor using an angular velocity sensor and an acceleration sensor for detecting the direction and acceleration of a moving body, and more particularly to a hybrid sensor for moving the moving body during movement.
The present invention relates to a hybrid sensor that corrects a sensitivity drift and an offset drift of an angular velocity sensor or an acceleration sensor based on an angular velocity signal and an acceleration signal detected by both sensors.

[0002]

2. Description of the Related Art A conventional hybrid sensor is provided with an angular velocity sensor and a geomagnetic sensor for detecting the direction of a moving body, like the direction detecting device disclosed in Japanese Patent Laid-Open No. 59-218913 by the present applicant. The azimuth (angle) signal based on the angular velocity detected by and the azimuth (angle) signal detected by the geomagnetic sensor are combined at an appropriate ratio, and the one configured to detect the direction of the moving body based on the combined output. Are known.

In such a hybrid sensor, the ratio of the azimuth (angle) signal detected by either the angular velocity sensor or the geomagnetic sensor is increased or decreased according to the situation of the moving body,
The direction of the moving body is detected by utilizing the characteristics of each sensor.

For example, a geomagnetic sensor senses geomagnetism,
Since the relative angle between the direction of the horizontal component and the traveling direction of the moving body is detected, there is a feature that the absolute direction of the moving body can be always detected at the present time. However, the geomagnetic sensor is greatly affected by disturbance when the moving body passes through a railroad crossing, an iron bridge, or the like.

On the other hand, since the angular velocity sensor is composed of a gas rate sensor which detects the change in resistance of the thermosensitive resistance element by the gas flow sealed in the container to detect the angular velocity of the moving body, it is hardly affected by disturbance. There is. However, the angular velocity sensor has a drift in sensitivity and an offset, which causes an error in an azimuth (angle) signal obtained by integrating the angular velocity, and accumulates over time to cause a large error.

In the conventional hybrid sensor using the above characteristics, the ratio detected by the geomagnetic sensor is increased (100%) in the initial stage of the movement of the moving body, and the ratio of the angular velocity sensor is gradually increased and the ratio of the geomagnetic sensor is increased. Is performed so that the continuity of detection due to the switching is not lost, and finally the ratio of the angular velocity sensor reaches 100%.

Further, even when the moving body is traveling while the proportion of the angular velocity sensor is 100%, if the non-stop state of the moving body continues for a long time, the non-stop time is monitored to determine the proportion of the angular velocity sensor. It is configured to reduce, increase the percentage of the geomagnetic sensor, and avoid sensitivity drift and offset drift of the angular velocity sensor.

As described above, the conventional hybrid sensor is provided with the geomagnetic sensor and the angular velocity sensor, and the ratio of detection is varied and adjusted according to the running state of the moving body, so that the direction of the moving body can be accurately detected. It is configured to be performed.

Further, a geomagnetic sensor and an angular velocity sensor are provided together, and the detection angle of the geomagnetic sensor or the angular velocity sensor is detected while comparing the detection angle detected by the geomagnetic sensor and the detection angle based on the angular velocity detected by the angular velocity sensor. There is also known a hybrid sensor that is configured to correct the error factor of the other sensor so that the angle is regarded as accurate and the deviation between the detected angle of the sensor regarded as accurate and the detected angle of the other sensor is eliminated. .

[0010]

Since the conventional hybrid sensor is equipped with a geomagnetic sensor, it is affected by a disturbance due to magnetization when passing through a railroad crossing or an iron bridge.
For example, when switching from a geomagnetic sensor to an angular velocity sensor,
Alternatively, when the angle detected by the geomagnetic sensor is considered to be accurate, the angle detected by the geomagnetic sensor changes, and there is a problem that an accurate direction cannot be detected.

Further, since the conventional hybrid sensor is provided with the angular velocity sensor, drift occurs in the sensitivity and the offset value due to temperature change and temporal change, and the integrated value of the drift is accumulated in the azimuth angle which is the time integral of the angular velocity. Therefore, there is a problem that the error increases.

The present invention has been made to solve such a problem, and its purpose is to correct the sensitivity drift and the offset drift even when the moving body is moving, and act on the moving body direction based on the angular velocity or on the moving body. An object of the present invention is to provide a hybrid sensor including an angular velocity sensor and an acceleration sensor that can detect acceleration with high accuracy.

[0013]

In order to solve the above-mentioned problems, a hybrid sensor according to the present invention includes an angular velocity sensor, an acceleration sensor, an angular velocity signal from these sensors, an acceleration signal, and a velocity signal from the velocity sensor. Based on the above, a sensor correction means for correcting the sensitivity coefficient and the offset value of the angular velocity sensor or the acceleration sensor is provided, and the direction of the moving body or the acceleration acting on the moving body is detected during movement.

Further, in the hybrid sensor according to the present invention, the sensor correction means includes sensor data storage means for reading and storing angular velocity signals, acceleration signals and velocity signals from the respective sensors a predetermined number of times within a predetermined time, and sensor data. It is characterized in that variable calculation means for calculating the sensitivity coefficient and offset value based on the data stored in the storage means and control means for controlling the sensor data storage means and the variable calculation means are provided.

Further, in the hybrid sensor according to the present invention, the sensor correction means uses the angular velocity signals from the respective sensors,
Sensor data storage means for reading and storing acceleration signals and velocity signals a predetermined number of times within a predetermined time, variable calculation means for calculating sensitivity coefficient and offset value based on the data stored in the sensor data storage means, and variable calculation It is characterized in that a calculation means for calculating an actual acceleration or an angular velocity based on an output from the means, a sensor data storage means, a variable calculation means, and a control means for controlling the calculation means are provided.

Further, in the hybrid sensor according to the present invention, the variable calculation means is provided with a final data storage section for storing the sensitivity coefficient and the offset value calculated immediately before the moving body stops, and when the moving body starts to move again, It is characterized in that the actual angular velocity is calculated based on the final data from the data storage unit.

[0017]

The hybrid sensor according to the present invention is provided with the sensor correction means and corrects the sensitivity coefficient and the offset value of the angular velocity sensor or the acceleration sensor during movement,
The direction of the moving body or the acceleration acting on the moving body can be accurately detected.

In the hybrid sensor according to the present invention, the sensor correction means is provided with the sensor data storage means, the variable calculation means and the control means, and the angular velocity signal, the acceleration signal and the velocity signal are read a predetermined number of times within a predetermined time. Since the sensitivity coefficient and offset value of the angular velocity sensor or acceleration sensor are accurately calculated and corrected based on the stored data, even if the sensitivity and offset drift of the angular velocity sensor or acceleration sensor is large, The direction or the acceleration acting on the moving body can be accurately detected.

Further, in the hybrid sensor according to the present invention, the sensor correction means is provided with the sensor data storage means, the variable operation means, the operation means and the control means, and the angular velocity signal, the acceleration signal and the velocity signal are given a predetermined number of times within a given time. Just read and store it, and calculate the sensitivity coefficient and offset value of the angular velocity sensor or acceleration sensor accurately based on the stored data, and calculate the angular velocity or acceleration based on the calculation result of the sensitivity coefficient and offset value. The direction of the moving body or the acceleration acting on the moving body can be accurately detected.

Further, in the hybrid sensor according to the present invention, the variable calculation means is provided with a final data storage unit to store the sensitivity coefficient and the offset value calculated immediately before the moving body stops, and the stored data is stored when the moving body starts to move again. Since the angular velocity is calculated based on, the accurate angular velocity can be obtained even at the start of re-movement.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory diagram relating to direction detection of a hybrid sensor according to the present invention. When a moving body (for example, a vehicle) M moves along a locus R in an arc having a radius of curvature r, the velocity of the moving body M at an arbitrary point P on the locus R is v,
Assuming that the angular velocity is ω and the acceleration that is perpendicular to the velocity v and acts in the direction of the center of the arc is α, the relationship of the mathematical formula 1 is established between the angular velocity ω, the acceleration α, the velocity v, and the radius of curvature r, and The relational expression of the angular velocity ω, the acceleration α, and the velocity v is obtained without including the curvature radius r that cannot be measured during traveling.

[0022]

[Equation 1]

Next, the angular velocity detected by the angular velocity sensor mounted on the moving body M is ω _N , the true value of the angular velocity is ω _SN , the sensitivity coefficient including the drift of the angular velocity sensor, and the offset value are a and b, respectively. If the acceleration detected by the acceleration sensor mounted on the body M is α _N , the true value of the acceleration is α _SN , and the offset value including the drift of the acceleration sensor is c, then
The relational expression of is obtained.

[0024]

[Equation 2]

The sensitivity coefficient a and the offset values b and c represent drift changes which change with time of the sensor itself and changes due to the passage of time or temperature, all of which change over a relatively long period of time, a few seconds. It is regarded as a constant value in a short time. Further, from Equation 2, the angular velocity sensor has a sensitivity change and an offset change, and the acceleration sensor has an offset change but does not have a sensitivity change. Then, the actual angular velocity (true value) ω _SN is calculated.

Further, the speed sensor is supposed to detect an accurate speed, and the speed v detected by the speed sensor is the speed v of equation (1).
_Replacing with _N , with unknowns a, b, c, ω _SN ,
Equation 3 shows the basic equation for _obtaining α _SN . The subscript ( _N ) represents the number of times the angular velocity sensor, the acceleration sensor, and the velocity sensor detect.

[0027]

[Equation 3]

In Equation 3, variables (unknown numbers) are a, b,
The number of equations is 3 for 5 of c, ω _SN , and α _SN ,
The equation increases by 3 each time each sensor measures once,
Since the variables a, b, and c can be regarded as constant for a short time of about several seconds, the variable increases by 2 each of ω _SN and α _SN for each measurement by each sensor, so the number of measurements N is 3N.
= 5 + 2 (N-1), the equation and the number of variables match three times, and the variables are calculated by performing measurements with each sensor three times within a short predetermined time of several seconds. Measurements are performed three times using the angular velocity sensor, the acceleration sensor, and the velocity sensor, and the equation 4 corresponding to the number of measurement times N = 1 to 3 in Equation 3 is summarized for ω _SN and α _SN .

[0029]

[Equation 4]

Solving the six equations (N = 1 to 3) of equation 4,
The variables a, b, and c are calculated as a = A, b = B, and c = C,
The true value ω _{SN (= 3)} of the angular velocity at the third measurement is the sensitivity coefficient A,
Offset value B and angular velocity ω detected by the angular velocity sensor
_The result obtained from Equation 4 using _{N (= 3)} is shown in Equation 5. If necessary, the true value of the acceleration α _{SN (= 1} to ₃₎ can also be calculated from Equation 3 from the deviation between the acceleration α _{N (= 1} to ₃₎ detected by the acceleration sensor and the offset value c (= C). .

[0031]

[Equation 5]

The angle θ can be calculated from the equation 6 by integrating the true value ω _{SN (= 3)} of the angular velocity obtained by the equation 5 from the time t = 0 to the predetermined time To.

[0033]

[Equation 6]

As described above, the sensitivity coefficient a and the offset are obtained by combining the angular velocity sensor having the sensitivity coefficient a and the offset value b which change with time, and the acceleration sensor having the offset value c which changes with the time and having stable sensitivity. By calculating the values b and c, it is possible to calculate accurate angular velocity and acceleration while the moving body is traveling.

Further, an acceleration sensor having a sensitivity coefficient (coefficient d) and an offset value c which change with time,
It is also possible to compute the sensitivity coefficients a and d and the offset value c by combining an angular velocity sensor having a stable sensitivity, which has an offset value c that changes with time, and to calculate accurate angular velocity and acceleration while the moving body is running. .

FIG. 2 is a block diagram of the essential parts of the hybrid sensor according to the present invention. In FIG. 2, the hybrid sensor 1 includes an angular velocity sensor 2, an acceleration sensor 3, a sensor correction unit 4, and an azimuth angle calculation unit 9,
The sensitivity coefficient drift and offset drift of the angular velocity sensor 2 and the offset drift of the acceleration sensor 3 are calculated based on the angular velocity signal ω _S from the angular velocity sensor 2, the acceleration signal α _S from the acceleration sensor 3, and the moving body M (for example,
(Vehicle) is corrected based on a vehicle speed signal v from an external vehicle speed sensor 10 to calculate an actual actual angular velocity ω _SN or an actual acceleration α _SN , and an azimuth angle θ is calculated from the actual angular velocity ω _SN. Thus, the acceleration acting on the moving body M is detected from the direction of the moving body M and the actual acceleration α _SN . It should be noted that the start and stop of the hybrid sensor 1 is configured to be controlled by, for example, the ignition information Ig from the ignition switch 11.

The sensor correction means 4 is basically composed of a microprocessor and comprises a sensor data storage means 5, a variable calculation means 6, a calculation means 7 and a control means 8. The sensor data storage means 5 is composed of an interface circuit, an A / D converter, a memory (RAM), etc., and each sensor receives a control signal S1 from the control means 8 a plurality of times (for example, three times within a few seconds). The detected angular velocity signal ω _S , the acceleration signal α _S , and the analog signal of the vehicle speed signal v are converted into corresponding digital signals, and the sensor data D _O (each data of three times of the expression 3:
ω _{N (= 1} to ₃₎ , α _{N (= 1} to ₃₎ , v _{N (= 1} to ₃₎ )
The stored sensor data D0 is provided to the variable calculation means 6.

The variable calculation means 6 is provided with a calculation means for executing the calculation formula of the equation 4, and the sensor data D is generated by the control signal S2.
Based on _O , the sensitivity coefficient A of the angular velocity sensor 2, the offset value B, and the offset value C of the acceleration sensor 3 are calculated,
The sensitivity coefficient signal A, the offset value signal B, and the offset value signal C are output to the calculating means 7.

The arithmetic means 7 has arithmetic means for executing the arithmetic expressions of the equations 5 and 3, and the control signal S3 causes the sensitivity coefficient A, the offset value B, and the angular velocity data ω _{N (} 3) of the sensor data D _{O at} the third time. _{= 3)} , the actual angular velocity ω _{SN (= 3)} is calculated, the actual angular velocity signal ω _SN is output, and based on the offset value C and the third acceleration data α _{N (= 3)} of the sensor data D _O. Then, the actual acceleration α _SN is calculated and the actual acceleration signal α _SN is output.

The control means 8 is a ROM for storing a reference clock circuit, a timer circuit, a sequencer circuit and control software.
Etc., and provides the control signals S1 to S3 to the sensor data storage means 5, the variable calculation means 6, and the calculation means 7, respectively, and the order and timing of signal acquisition, storage, calculation, output, etc. to each means. Are configured to control. Further, the control means 8 provides the control signal S4 to the azimuth angle calculation means 9, and controls the timing of the calculation of the azimuth angle calculation means 9 and the calculation result output (azimuth angle θ).

Further, the control means 8 takes in the angular velocity signal ω _S , the acceleration signal α _S , and the vehicle speed signal v three times in a short period (to) of, for example, several seconds, and the sensitivity coefficient A, the offset values B and 3. The actual angular velocity calculation ω _{SN (= 3)} corresponding to the angular velocity signal ω _S and the actual angular velocity calculation ω _{SN (= 3)} are integrated for a predetermined time To to obtain the azimuth angle θ, and the azimuth θ is calculated. The sum is set to be the cycle T (= to + To) and the calculation is repeated. The activation and deactivation of the control unit 8 is controlled by the information Ig provided by the ignition switch 11 that activates and deactivates the moving body M (for example, a vehicle).

The azimuth angle calculating means 9 is provided with the integral calculating means shown in the equation 6, and the control signal S4 from the control means 8 integrates the real angular velocity ω _{SN (= 3)} from time to to To to obtain the azimuth angle θ.
Is calculated and output.

FIG. 3 is a block diagram showing the essential part of one embodiment of the variable calculating means provided in the sensor correcting means. The variable calculation means 6 includes a variable calculation part 21, a final data storage part 22, a timer circuit 23, and a switching means SW. The variable calculation unit 21
The control signal S2 is provided with an arithmetic means for executing the arithmetic expression of the equation 4.
According to the sensor data D _O , the sensitivity coefficient A of the angular velocity sensor 2, the offset value B and the offset value C of the acceleration sensor 3 are calculated, and the sensitivity coefficient signal A and the offset value signal B are stored in the final data storage unit 22 and the switching means. SW,
The offset value C is output to each switching means SW.

The final data storage unit 22 is composed of a rewritable memory such as a RAM. When the ignition switch 11 shown in FIG. 2 is turned off to stop the moving body M, the stop signal St of the control signal S2 is provided. Then, the sensitivity coefficient A (= Ao) from the variable calculation unit 21 and the offset value B
(= Bo) is taken in and saved as the final data Ao and Bo. In addition, when the ignition switch 11 is turned on and the moving body M starts to move again, the final data storage unit 22 receives the start signal Sr of the control signal S2 and saves the final data Ao, Bo. Is output to the switching means SW for a predetermined time.

The switching means SW is composed of a logical switch or the like,
Controlled by the timer information T provided from the timer circuit 23, the sensitivity coefficient signal A, the offset value signals B and C from the variable calculator 21 and the final data Ao and Bo from the final data storage 22 are switched, The calculation means 7 is provided.

In this way, the variable calculation means 6 determines the sensitivity coefficient signal A and the offset value signal B when the ignition switch 11 of the moving body is turned off as the final data A.
O and Bo are stored and provided as final data Ao and Bo at a predetermined time when the ignition switch 11 is turned on and the moving body starts moving again. Therefore, the sensitivity coefficient signal A at the start of re-moving and Offset value signal B
The hybrid sensor 1 can calculate and output the azimuth angle θ based on the actual angular velocity ω _SN from the start of the re-movement, while avoiding the state in which is not determined.

In this embodiment, the acceleration sensor having a small sensitivity drift is used to correct the sensitivity drift and the offset drift of the angular velocity sensor during the traveling of the moving body so that the direction of the moving body can be accurately detected. However,
The angular velocity sensor having a small sensitivity drift may be used to correct the sensitivity drift and the offset drift of the acceleration sensor during traveling of the moving body, and to detect the acceleration acting on the moving body with high accuracy.

The present invention can also be applied to control of mobile robots, active suspension control for vehicles, 4WS control, anti-braking system and the like.

[0049]

As described above, the hybrid sensor according to the present invention is provided with the angular velocity sensor, the acceleration sensor, and the sensor correcting means, and the sensor correcting means is provided on the angular velocity signal, the acceleration signal, and the moving body during traveling. The velocity signal from the velocity sensor is taken in multiple times, the sensitivity coefficient and offset value of the angular velocity sensor are calculated to calculate the actual angular velocity, and the azimuth angle calculation means calculates the azimuth angle based on this angular velocity. Even if there is a sensitivity drift and an offset drift that change over time, the azimuth angle can be calculated and corrected, and the direction of the moving body can be accurately detected.

Since the sensor correction means calculates and corrects the sensitivity coefficient and offset value of the acceleration sensor, the actual acceleration can be detected.

Further, in the hybrid sensor according to the present invention, the variable calculation means is provided with a final data storage section for storing the sensitivity coefficient and the offset value calculated immediately before the moving body is stopped, and the stored data is stored when the moving body starts to move again. Since the angular velocity is calculated based on, it is possible to detect the accurate direction even at the start of re-movement.

Therefore, it is possible to provide a highly convenient hybrid sensor having excellent detection accuracy and reliability.

[Brief description of drawings]

FIG. 1 is an explanatory diagram related to direction detection of a hybrid sensor according to the present invention.

FIG. 2 is a block diagram of a main part of a hybrid sensor according to the present invention.

FIG. 3 is a block diagram of the essential part of an embodiment of a variable calculation means provided in the sensor correction means.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hybrid sensor, 2 ... Angular velocity sensor, 3 ... Acceleration sensor, 4 ... Sensor correction means, 5 ... Sensor data storage means, 6 ... Variable calculation means, 7 ... Calculation means, 8 ... Control means, 9 ... Azimuth calculation means 10 ... Speed sensor, 11 ... Ignition switch, 21 ... Variable operation part, 22 ... Final data storage part, 23 ... Timer circuit, SW ... Switching part, A ...
Sensitivity coefficient, B, C ... Offset value, Ao, Bo ... Final data, D _O ... Sensor data, M ... Moving body, S1-S4 ...
Control signal, v ... Vehicle speed signal, α _S ... Acceleration signal, α _SN ... Actual acceleration, ω _S ... Angular velocity signal, ω _SN ... Real angular velocity, θ ... Azimuth angle.

Claims (4)

[Claims] 1. An angular velocity sensor, an acceleration sensor, and a sensitivity coefficient and an offset value of the angular velocity sensor or the acceleration sensor are corrected based on an angular velocity signal from these sensors, an acceleration signal, and a velocity signal from the speed sensor. A hybrid sensor, comprising: a sensor correction unit for detecting a direction of a moving body or an acceleration acting on the moving body during movement. 2. A sensor data storage means for reading the angular velocity signal, the acceleration signal and the velocity signal from each of the sensors a predetermined number of times within a predetermined time in the sensor correction means, and the sensor data storage means. 2. The hybrid according to claim 1, further comprising variable calculation means for calculating the sensitivity coefficient and the offset value based on the data obtained, and control means for controlling the sensor data storage means and the variable calculation means. Sensor. 3. A sensor data storage means for reading the angular velocity signal, the acceleration signal and the velocity signal from each of the sensors a predetermined number of times within a predetermined time and storing them in the sensor correction means, and the sensor data storage means. Variable calculation means for calculating the sensitivity coefficient and the offset value based on the data, calculation means for calculating the actual acceleration or angular velocity based on the output from the variable calculation means, the sensor data storage means, the variable The hybrid sensor according to claim 1, further comprising an arithmetic means and a control means for controlling the arithmetic means. 4. The variable calculation means is provided with a final data storage section for storing the sensitivity coefficient and the offset value calculated immediately before the moving body stops, and when the moving body starts to move again, the final data storage section is provided. The hybrid sensor according to claim 1, wherein an actual angular velocity is calculated based on final data from the section.