JP2011191243A - Offset correction device for on-vehicle gyro - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an offset correction device for an on-vehicle gyro capable of correcting the offsets of a pitch rate gyro, even if a vehicle is in the middle of traveling. <P>SOLUTION: An offset correction means 104 determines a mean value of a prescribed period T of angular velocity, during a period in which angular velocity determined from a rotation angle detected by a yaw rate gyro 102 is below a prescribed angular velocity A, from among the angular velocities determined from the rotation angle detected by the pitch rate gyro 101, and performs correction by using the mean value as an offset value of the pitch rate gyro 101. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an on-vehicle gyro offset correction device capable of correcting an on-vehicle gyro offset voltage (hereinafter referred to as “offset”) generated by temperature and humidity fluctuations.

  As a conventional offset correction device for an in-vehicle gyro, the turning angle of the vehicle is obtained from the output of the GPS receiver, and the turning angle of the vehicle is obtained by integrating the output data of the gyro, and based on the difference between these two angles. There is one that corrects the output of the gyro by obtaining an offset even while the vehicle is running. For example, Patent Document 1 is known as a prior art document.

JP-A-6-26865

  However, a conventional gyro offset correction device for an in-vehicle gyro corrects a gyro sensor (hereinafter referred to as a “yaw rate gyro”) that detects an angular velocity (hereinafter referred to as a “yaw rate”) of rotation about the vertical direction of the vehicle. It is.

  In recent years, in addition to this yaw rate gyro, a gyro sensor (hereinafter referred to as “pitch rate gyro”) that detects an angular velocity of rotation about the left and right direction of the vehicle (hereinafter referred to as “pitch rate”) in addition to the purpose of calculating road inclination. ) Is being installed in vehicles.

  When the conventional on-vehicle gyro offset correction device is applied to the offset correction of the pitch rate gyro, there are the following problems.

  When correcting the offset of the yaw rate gyro, only the yaw rate component may be removed using the direction change information obtained from the GPS (Global Positioning System) receiver. On the other hand, when correcting the offset of the pitch rate gyro, it is necessary to remove the yaw rate component.

  Offset correction is easy if the vehicle stops frequently. The output of the gyro sensor when the vehicle is stopped includes only noise components and offsets due to vehicle vibrations and power supply voltage fluctuations. For this reason, if these noise components are removed by the averaging process, the offset can be easily calculated and removed.

  On the other hand, offset correction of the pitch rate gyro when the vehicle is running is not easy. The detection result of the pitch rate gyro includes, for example, the angular velocity component of the yaw rate when the vehicle turns right or left on an inclined road. Will overlap. This occurs because the detection axis of the pitch rate gyro is inclined. In such a case, the pitch rate gyro offset cannot be accurately calculated unless the angular velocity component of the yaw rate is removed from the detection result of the pitch rate gyro.

The present invention has been made to solve the conventional problems, and an object thereof is to provide an on-vehicle gyro offset correction device capable of accurately correcting an offset of a pitch rate gyro even during traveling.

  In order to achieve the above object, the present invention provides an angular velocity during a period in which the angular velocity obtained from the rotational angle detected by the yaw rate gyro is the predetermined angular velocity A or less among the angular velocities obtained from the rotational angle detected by the pitch rate gyro. The average value of the predetermined time T is obtained, and this average value is corrected as an offset value of the pitch rate gyro.

  The on-vehicle gyro offset correction apparatus according to the present invention calculates the average value of the angular velocity of the pitch rate excluding the angular velocity of the pitch rate during a period in which the angular velocity of the yaw rate is greater than the predetermined angular velocity A.

  As described above, since the offset correction apparatus for the on-vehicle gyro according to the present invention calculates the offset using the angular velocity of the pitch rate during a period not affected by the yaw rate, the offset of the pitch rate gyro is accurately corrected even during traveling. There is an effect that it is possible.

The block diagram of the navigation apparatus in one embodiment of this invention The block diagram of the offset correction apparatus in one embodiment of this invention Flow chart for explaining the operation of the apparatus The figure explaining the relationship between the mounting angle and yaw rate of the device Diagram for explaining the output value of each gyro

  Hereinafter, a navigation apparatus 2 including an offset correction apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a block diagram of a navigation apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram of an offset correction apparatus according to an embodiment of the present invention.

  The navigation apparatus according to one embodiment of the present invention includes an offset correction apparatus 1 that outputs a result of correcting errors in outputs of various gyro sensors (to be described later), an output of the offset correction apparatus 1, and detection of an acceleration sensor 4. Based on the result, a control unit 3 for calculating the current position of the vehicle provided with the navigation device 2 is provided.

  The control unit 3 reads out a map image corresponding to the calculated current position from the storage unit 5 and outputs the map image to the display control unit 6. The display control unit 6 displays the map image on the display device 7.

  In addition, the navigation device 2 includes a speaker 8, and the control unit 3 performs control so as to guide a route to the destination to the user of the navigation device 2 by voice from the speaker 8.

  Hereafter, each said structure is demonstrated in detail.

  The offset correction apparatus 1 corrects an offset value (hereinafter referred to as “offset correction”) from the output of the pitch rate gyro 101 for calculating the pitch rate, and outputs the offset value.

The offset correction apparatus 1 includes an offset correction unit 104 that performs offset correction of the pitch rate gyro 101. This offset correction means 104 performs offset correction of the pitch rate gyro 101 in consideration of at least one output of the yaw rate gyro 102 for calculating the yaw rate and the GPS receiver 103. The configuration of the offset correction unit 104 will be described later.

  The pitch rate gyro 101 is a gyro sensor that calculates and outputs a pitch rate (hereinafter referred to as a “pitch rate value”), which is an angular velocity of rotation about the horizontal direction of the vehicle. By installing the pitch rotation direction as an axis, it is possible to calculate the relative rotation amount of the host vehicle in the vertical direction. By integrating the pitch rate value, it can be applied to the calculation of road inclination.

  The yaw rate gyro 102 is a gyro sensor that calculates and outputs a yaw rate that is an angular velocity of rotation about the vertical direction of the vehicle (hereinafter referred to as a “yaw rate value”). It is possible to calculate a relative azimuth change amount in the traveling direction of the own vehicle from the yaw rate value. By combining with a GPS receiver, a geomagnetic sensor, etc., the absolute direction of the vehicle can be calculated.

  The pitch rate gyro 101 and the yaw rate gyro 102 may be constituted by, for example, a mechanical gyro or a vibration gyro.

  The GPS receiver 103 receives radio waves from a plurality of GPS satellites and demodulates the received signals to measure the absolute position of the receiver.

  The control unit 3 controls each unit of the navigation device 2. For example, the control unit 3 includes a CPU, a ROM (Read Only Memory) that stores a program for controlling the CPU, and a RAM (Random Access Memory) that temporarily stores data. The CPU reads and executes a program stored in the ROM.

  The acceleration sensor 4 detects at least the acceleration of the longitudinal detection axis and outputs the result (hereinafter referred to as “acceleration information”). The acceleration sensor 4 can be mounted with a sensor capable of detecting the acceleration of the left-right direction detection axis and the acceleration of the vertical direction detection axis.

  The storage unit 5 stores various map information. Here, the map information is, for example, road data, facility data, and background data. The storage unit 9 is composed of a storage medium such as a hard disk or a flash memory.

  The storage unit 5 does not have to store data in advance, and may be downloaded from a distribution center by communication means such as a mobile phone (not shown).

  The display control unit 6 has a function of performing image processing so that the map information read from the storage unit 5 can be displayed on the display device 7 under the control of the control unit 3.

  The display device 7 includes a display device such as a liquid crystal display, and has a function of displaying a map image around the vehicle position along with guidance information such as the vehicle position mark and the optimum route under the control of the control unit 3.

  Next, the configuration of the offset correction unit 104 will be described in detail with reference to FIG.

The offset correction unit 104 includes an offset removal unit 105 that removes an offset from the output of the pitch rate gyro 101, an offset calculation unit 106 that calculates an offset value of the pitch rate gyro 101, and a travel that determines whether the vehicle is traveling The determination unit 107 is configured.

  The offset removing means 105 removes the offset value of the pitch rate gyro 101 calculated by the offset calculating means 106 from the output of the pitch rate gyro 101 and outputs the result. As a removal method, for example, the offset value calculated by the offset calculation means 106 is subtracted from the output of the pitch rate gyro 101.

  The offset calculation means 106 calculates an offset value superimposed on the pitch rate value output from the pitch rate gyro 101. At this time, the offset calculation means 106 calculates by considering at least one of the yaw rate value output from the yaw rate gyro 102 or the output of the GPS receiver 103.

  Specifically, the offset value of the pitch rate value of the pitch rate gyro 101 is obtained by averaging the pitch rate value over a period of a predetermined time T. At this time, the yaw rate value output from the yaw rate gyro 102 is a predetermined angular velocity. A pitch rate value during a period greater than A (deg / sec) is excluded, and an average value is obtained from the pitch rate values during a period when the yaw rate value is equal to or less than a predetermined angular velocity A (calculation method 1). The angular velocity A (deg / sec) is, for example, about 10 (deg / sec).

  The traveling determination unit 107 determines whether or not the vehicle is traveling. For this determination, the output of the GPS receiver 103 or the acceleration sensor 4 is used.

  Although it can be determined from the speed information obtained from the GPS receiver 103 that the vehicle is traveling, the GPS receiver 103 is not always capable of positioning, and therefore is determined from the output of the acceleration sensor 4. It is desirable.

  When determining whether or not the vehicle is running from the output of the acceleration sensor 4, the acceleration output from the acceleration sensor 4 is sampled, and the variation width of the acceleration is calculated. It is determined whether or not the variation width falls within a predetermined width. If it is within the predetermined width, it is determined that the vehicle is stopped, while if it is not within the predetermined width, it is determined that the vehicle is running.

  The result of determination as to whether the vehicle is traveling by the travel determination unit 107 is input to the offset calculation unit 106. The calculation method 1 is executed only when the traveling determination unit 107 determines that the vehicle is traveling. This is because the offset can be easily calculated and removed by averaging the pitch rate value while the vehicle is stopped.

  The processing operation of the navigation device 2 configured as described above will be described with reference to FIG.

  FIG. 3 is a flowchart for explaining the operation of the navigation apparatus according to the embodiment of the present invention. More specifically, FIG. 3 shows processing performed by each unit of the offset correction unit 104.

  First, in step S01, the traveling determination means 107 determines whether the vehicle is traveling.

  When the vehicle is traveling (YES in S01), as step S02, the offset calculating means 106 acquires the yaw rate value from the yaw rate gyro 102 and acquires the pitch rate value from the pitch rate gyro 101.

  Following step S02, the offset calculating means 106 extracts a pitch rate value when the yaw rate value is equal to or less than a predetermined angular velocity A (deg / sec) (S03). Specifically, only a pitch rate value whose yaw rate value is equal to or less than a predetermined angular velocity A (deg / sec) is extracted during a predetermined period (predetermined time T) for averaging the pitch rate values. is there.

  Subsequent to step S03, the offset calculation means 106 obtains an average value for every predetermined time T with respect to the extracted pitch rate value as step S04. Since the effect of the low-pass filter can be obtained by averaging, the noise component included in the pitch rate value is removed, and the offset value can be obtained.

  The average value of the pitch rate values calculated here does not include the yaw rate value component. That is, the offset value can be obtained by removing the influence of the yaw rate value component. The offset calculation unit 106 outputs the obtained offset value to the offset removal unit 105.

  After step S04, as step S05, the offset removing unit 105 performs offset correction by subtracting the offset value obtained by the offset calculating unit 106 from the pitch rate value output from the pitch rate gyro 101. The offset removing unit 105 outputs the corrected pitch rate value.

  When the vehicle is not traveling (NO in S01), that is, when the vehicle is stopped, the offset calculating means 106 calculates an offset value by calculating an average value for each predetermined time T with respect to the pitch rate value. (Step S06). When the vehicle is stopped, the pitch rate value need not be extracted because it is not affected by the yaw rate value.

Finally, offset correction according to an embodiment of the present invention will be described with reference to FIG. 4 and FIG.
FIG. 4 is a diagram for explaining the relationship between the mounting angle of the navigation device 2 and the yaw rate. FIG. 5 is a diagram for explaining the output values of the pitch rate gyro 101 and the yaw rate gyro 102.

  The solid line graph in the upper part of FIG. 5 is the pitch rate value output by the pitch rate gyro 101. The solid line graph in the lower part of FIG. 5 is the yaw rate value output from the yaw rate gyro 102.

  For example, as can be seen by comparing the pitch rate value and the yaw rate value during the period from time T1 to T2, the pitch rate value is affected by the change in the yaw rate value.

  The broken line graphs (L1, L2, L3) in the upper part of FIG. 5 represent the set values of the offset with respect to time. These graphs are hereinafter referred to as offset curves.

  Here, the offset curve L1 represents the offset of the pitch rate gyro 101 in the initial state. Further, the offset curve L2 represents an offset that is simply calculated from the average value of the pitch rate without considering the change in the yaw rate value. This offset curve L2 is an offset curve calculated in error.

When the yaw rate value is large, the yaw rate component is also output to the output of the pitch rate gyro 101 as shown in FIG. This occurs when a large yaw rate value is generated while the detection axis of the pitch rate gyro 101 is tilted. For example, as shown in FIG. 4, consider a case where a yaw rate ωy occurs on a road having a roll inclination θ. Here, the “roll inclination” refers to an inclination that gives an inclination with respect to the left-right axis of the vehicle.

  In this case, the yaw rate value is output to the yaw rate gyro output Vy and the pitch rate gyro output Vp according to the following relational expression.

Vy = ωy · cos θ (Formula 1)
Vp = ωy · sinθ (Formula 2)
If the output value of the pitch rate gyro 101 at this time is used for calculating the offset, there is a possibility that an error corresponding to the yaw rate value component occurs. The case where this error occurs is the offset curve L2. The offset curve L2 is a curve different from the actual offset because the output includes the yaw rate value component.

  Therefore, pitch rate values during a period in which the yaw rate value output from the yaw rate gyro 102 is greater than the predetermined angular velocity A (deg / sec) are excluded (periods T1-T2 and T3-T4 in FIG. 5). The average value of the yaw rate values obtained in this way is the offset curve L3. The offset curve L3 represents an offset during the traveling of the pitch rate gyro 101. This offset curve L3 is a correct offset curve excluding the influence of the yaw rate value.

  As described above, according to the embodiment of the present invention, the average value of the pitch rate values is calculated by excluding the angular velocity of the pitch rate during the period in which the yaw rate value is larger than the predetermined angular velocity A.

  The yaw rate value changes by nearly 90 degrees when the vehicle turns right or left. On the other hand, the pitch rate value causes only an angle change of about 0 to 5 degrees at most. Further, the pitch rate value converges immediately without the inclination continuously changing in the same rotation direction.

  Therefore, the pitch rate value component during traveling can be handled in the same manner as the noise component in the long term, and can be removed by the averaging process. For this reason, in order to calculate the offset of the pitch rate gyro 101 during traveling, means for removing the yaw rate value component included in the output of the pitch rate gyro 101 is important.

  The yaw rate value component included in the output of the pitch rate gyro 101 changes depending on the road inclination, the mounting angle of the navigation device 2, and the like, so it is not easy to remove. Further, since the output tendency of the yaw rate value component may be inclined in the same rotation direction, it cannot be removed even if the averaging process is simply performed.

Therefore, in the embodiment of the present invention, since the offset value is calculated using the pitch rate value in the period not affected by the yaw rate value, the pitch rate gyro offset can be accurately corrected even during traveling. There is an effect.

In one embodiment of the present invention, an average value (referred to as a “first average value”) is obtained from the yaw rate gyro 102 as a pitch rate value during a period in which the yaw rate value is equal to or less than a predetermined angular velocity A (calculated). Although described as method 1), the following method may be used.

  The angular velocity of the yaw rate that detects rotation about the vertical direction of the vehicle is calculated from the change in the current position obtained by the GPS receiver 103, and the pitch in a period in which this yaw rate value is greater than the predetermined angular velocity A (deg / sec) The average value (referred to as “second average value”) can be obtained from the pitch rate value during the period in which the yaw rate value is equal to or lower than the predetermined angular velocity A (calculation method 2).

  In this way, even under a condition where the yaw rate value is not correctly calculated by the yaw rate gyro 102, the effect of the yaw rate value component can be removed from the pitch rate value and the offset correction can be performed accurately.

  Note that either one of the calculation method 1 and the calculation method 2 may be used, or both may be performed simultaneously. The calculation method 1 using the yaw rate gyro 102 is advantageous because the reception environment of the GPS receiver 103 is deteriorated in an urban area with many tunnels and buildings.

  In the embodiment of the present invention, when the speed of the host vehicle is higher than a predetermined value, the second average value is corrected as the offset value of the pitch rate gyro instead of the first average value. be able to.

  When the speed of the host vehicle exceeds a predetermined value (for example, about 20 km / h), the accuracy of the yaw rate calculated from the GPS receiver 103 is improved. The yaw rate is obtained from the positional relationship between the previous position and the current position calculated by the GPS receiver 103, and the longer the distance, the less affected by the position calculation accuracy and the higher the accuracy. Therefore, when traveling at high speed, the traveling distance in a predetermined time becomes longer and the accuracy is improved. Therefore, when the speed of the host vehicle is higher than a predetermined value, the second average value obtained by the GPS receiver 103 is more accurate than the first average value, which is advantageous for improving the correction accuracy. It becomes.

  The offset correction unit 104 may calculate and remove the offset by averaging the yaw rate value output from the yaw rate gyro 102 when the vehicle is stopped.

  At this time, when the vehicle continuously travels without stopping for a predetermined time or longer, the correction of the yaw rate gyro 102 is not performed for the predetermined time or longer. For example, it is a case where the vehicle travels for a long time in a place such as a mountain road or a multilevel parking lot where a left and right turn with inclination is repeated. At this time, since the accuracy of the yaw rate gyro 102 may be lowered, the calculation method 2 using the GPS receiver 103 is advantageous instead of the calculation method 1.

  INDUSTRIAL APPLICABILITY The on-vehicle gyro offset correction device according to the present invention can correct an offset even while traveling, and is useful for a navigation device that calculates and displays the current position of the host vehicle based on the detection result of the gyro sensor. It is.

DESCRIPTION OF SYMBOLS 1 Offset correction apparatus 101 Pitch rate gyro 102 Yaw rate gyro 103 GPS receiver 104 Offset correction means 105 Offset removal means 106 Offset calculation means 107 Traveling determination means 2 Navigation apparatus 3 Control part 4 Acceleration sensor 5 Storage part 6 Display control part 7 Display apparatus 8 Speaker

Claims (6)

A yaw rate gyro that detects rotation about the vertical direction of the vehicle, a pitch rate gyro that detects rotation about the left and right direction of the vehicle, and offset correction means that performs offset correction of the pitch rate gyro while the vehicle is traveling An offset correction device for an in-vehicle gyro equipped with
The offset correction means includes a predetermined angular velocity T during a period in which the angular velocity obtained from the rotational angle detected by the yaw rate gyro is equal to or less than the predetermined angular velocity A among the angular velocities obtained from the rotational angle detected by the pitch rate gyro. An in-vehicle gyro offset correction apparatus characterized in that an average value of the gyro is calculated and the average value is corrected as an offset value of the pitch rate gyro. A GPS receiver that calculates the position of the host vehicle, a pitch rate gyro that detects rotation about the left-right direction of the vehicle, and an offset correction unit that performs offset correction of the pitch rate gyro while the vehicle is traveling. An on-vehicle gyro offset correction device,
The offset correction means calculates the angular velocity of the yaw rate about the vertical direction of the vehicle from the change in the position of the host vehicle calculated by the GPS receiver, and the angular velocity of the yaw rate is equal to or less than the predetermined angular velocity A. An on-vehicle gyro offset characterized in that an average value of a predetermined time T of an angular velocity obtained from a rotation angle detected by the pitch rate gyro in a period is obtained and the average value is corrected as an offset value of the pitch rate gyro. Correction device. A yaw rate gyro that detects rotation about the vertical direction of the vehicle, a GPS receiver that calculates the position of the host vehicle, a pitch rate gyro that detects rotation about the left and right direction of the vehicle, and a vehicle that is running An on-vehicle gyro offset correction device comprising offset correction means for performing offset correction of the pitch rate gyro,
The offset correction means includes a predetermined angular velocity T during a period in which the angular velocity obtained from the rotational angle detected by the yaw rate gyro is equal to or less than the predetermined angular velocity A among the angular velocities obtained from the rotational angle detected by the pitch rate gyro. Is obtained as a first average value, and an angular velocity of the yaw rate about the vertical direction of the vehicle is calculated from a change in the position of the host vehicle calculated by the GPS receiver, and the angular velocity of the yaw rate is a predetermined angular velocity. An average value of a predetermined time T of the angular velocity obtained from the rotation angle detected by the pitch rate gyro in a period equal to or less than A is obtained as a second average value, and one of the first and second average values An on-vehicle gyro offset correction device, wherein one average value is corrected as an offset value of the pitch rate gyro. The offset correction means corrects the first average value as the offset value of the pitch rate gyro when the position of the host vehicle calculated by the GPS receiver is a tunnel or an urban area. The offset correction apparatus of the vehicle-mounted gyroscope of Claim 3. The in-vehicle apparatus according to claim 3, wherein the offset correction means corrects the second average value as an offset value of the pitch rate gyro when the speed of the host vehicle is faster than a predetermined value. Gyro offset correction device. The offset correction means further corrects an offset value of the yaw rate gyro while the vehicle is stopped. When the vehicle has traveled without stopping for a predetermined time or longer, the second average value is calculated as the pitch rate gyro. 4. The on-vehicle gyro offset correction apparatus according to claim 3, wherein correction is performed as an offset value.