JP2013206418A - On-vehicle device and acceleration correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle device capable of automatically performing 0 point correction of acceleration even after being attached to a vehicle.SOLUTION: A CPU 10 acquires GPS position information from a GPS receiver 22, and discriminates whether or not a vehicle 5 is at a horizontal location (location of 0G) registered in an EEPROM 12 (S11). When it is not at the horizontal location, the CPU 10 repeats processing in a step 11, and waits for it to move to the registered horizontal location. On the other hand, when it is at the horizontal location, the CPU 10 performs 0 point correction of a G sensor 24, and updates a correction value registered in a memory built in the G sensor 24 or a memory built in the CPU 10 (S12).

Description

  The present invention relates to an in-vehicle device and an acceleration correction method that perform zero point correction of an acceleration sensor.

  Conventionally, acceleration sensors built in in-vehicle devices such as drive recorders need to be compensated for zero-point offset, etc., for tilting the in-vehicle device with respect to the horizontal plane and for sensor-specific zero correction when mounted on the vehicle. Met.

  At the time of attachment to a vehicle, it is generally performed that a vehicle-mounted device is fixed to the vehicle and then operated by connecting a PC to the vehicle-mounted device to perform zero point correction.

  Examples of this type of prior art include the following. Compare the actual driving history of the vehicle in the predetermined section with the road shape in the predetermined section, and if the actual driving history does not match the road shape, change the value of the zero point potential of the angular velocity sensor from the current value By doing this, the actual traveling history is made to coincide with the road shape (see Patent Document 1).

JP 2006-162330 A

  However, the conventional vehicle-mounted device has the following problems. Initially, even if the acceleration (G value) is corrected to zero, the mounting position of the vehicle-mounted device may be shifted due to an operation, etc., or a detection error due to a temperature change such as summer or winter may be added. The 0 point may not be accurate. As a result, the detection accuracy of the acceleration is lowered, and there is a concern that the detection of the impact on the vehicle may be hindered.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an in-vehicle device and an acceleration correction method capable of automatically performing zero-point correction of acceleration even after being attached to a vehicle. is there.

In order to achieve the above-described object, the vehicle-mounted device according to the present invention is characterized by the following (1) to (4).
(1) An on-vehicle device that is mounted on a vehicle and performs zero-point correction of an acceleration sensor that detects acceleration of the vehicle,
Registration means for registering a point where the acceleration is 0;
Correction value setting means for setting a correction value so that the acceleration detected by the acceleration sensor has a value of 0 at the point registered by the registration means;
Be provided.
(2) The vehicle-mounted device configured as described in (1) above,
The registration unit registers a point where the correction value is set by the correction value setting unit at a first time point and the acceleration detected by the acceleration sensor is 0,
The correction value setting means sets the correction value so that the acceleration detected by the acceleration sensor becomes a value 0 at a point registered by the registration means at a second time point after the first time point. To update.
(3) The vehicle-mounted device having the above configuration (1) or (2),
Comprising position detecting means for detecting the position of the vehicle;
The registration means registers the position of the vehicle detected by the position detection means as the point when the acceleration detected by the acceleration sensor is 0 even after a predetermined time has elapsed.
(4) The vehicle-mounted device according to any one of the above (1) to (3),
The registration means registers a plurality of points on the map where the acceleration is zero.

In order to achieve the above-described object, the acceleration correction method according to the present invention is characterized by the following (5).
(5) An acceleration correction method in which an on-vehicle device mounted on a vehicle performs zero-point correction of an acceleration sensor that detects acceleration of the vehicle,
A registration step of registering a point where the acceleration is 0;
A correction value setting step for setting a correction value so that the acceleration detected by the acceleration sensor becomes 0 at the point registered in the registration step;
Having

According to the vehicle-mounted device having the configuration (1) and the acceleration correction method having the configuration (5), the correction value is set so that the acceleration detected by the acceleration sensor becomes 0 at the registered point. Therefore, the zero point correction of the acceleration can be automatically performed even after being attached to the vehicle. Thereby, it is possible to detect an impact on the vehicle in an accident or the like with an accurate acceleration.
According to the vehicle-mounted device having the configuration (2), since the correction value is updated, the zero-point correction of the acceleration with high accuracy is continued.
According to the vehicle-mounted device having the configuration (3) or (4), the number of points where the correction value is set increases, so that the correction value can be updated more frequently.

  According to the present invention, the correction value is set so that the acceleration detected by the acceleration sensor becomes a value of 0 at the registered point. Therefore, the zero correction of the acceleration is automatically performed even after being attached to the vehicle. be able to. Thereby, it is possible to detect an impact on the vehicle in an accident or the like with an accurate acceleration.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1A and FIG. 1B are block diagrams showing the configuration (FIG. 1A) and appearance (FIG. 1B) of the drive recorder 1 in the embodiment. FIGS. 2A and 2B are diagrams showing the attachment position of the G sensor 24 (FIG. 2A) and the acceleration (FIG. 2B) detected when the G sensor 24 is tilted. is there. FIG. 3 is a diagram showing an overall flow from installation to operation of the drive recorder 1. FIG. 4 is a flowchart showing a registration procedure of a horizontal place (0G place). FIG. 5 is a diagram illustrating a map 30 displayed on the display device 60 in which a plurality of 0G locations (GPS position information) are registered. FIG. 6 is a flowchart showing an automatic zero point correction procedure. FIGS. 7A and 7B are flowcharts showing another automatic zero point correction procedure.

  An in-vehicle device and an acceleration correction method according to an embodiment of the present invention will be described with reference to the drawings. The vehicle-mounted device of the present embodiment is applied to a drive recorder mounted on a vehicle.

  FIG. 1A and FIG. 1B are block diagrams showing the configuration and appearance of the drive recorder 1 in the embodiment. FIG. 1A shows the configuration of the drive recorder 1, and FIG. 1B shows the appearance of the drive recorder 1.

  The drive recorder 1 has a CPU 10, a card I / F 11, a RAM 16, an EEPROM 12, a camera I / F 13, a sensor I / F 14, a speed I / F 15, a signal I / F 17, and an operation unit 18 in a housing 1 a of the drive recorder. .

  The CPU 10 incorporates a ROM, a RAM, a timer and the like in which a control program is stored, and controls the entire drive recorder 1. Various types of data are stored in the RAM 16. The EEPROM 12 stores information on a map (map) 30 and a horizontal place (0G place) described later is registered as a position on the map 30 (see FIG. 5).

  A card I / F 11 is a card I / F for trigger recording. A memory card (recording medium) 21 such as a CF card or an SD card (registered trademark) is detachably connected to the card I / F 11. The memory card 21 is a recording medium having a capacity of 2 Gbytes, for example.

  Here, trigger recording refers to recording data such as images for a certain period of time before and after when a trigger occurs intermittently, such as when an impact is detected exceeding a set threshold (G value). Point to.

  The camera I / F 13 is connected with a camera 23 that captures the front of the vehicle. The sensor I / F 14 is connected to a G sensor (acceleration sensor) 24 that detects the acceleration of the vehicle and senses an impact applied to the vehicle. Here, a semiconductor type such as a capacitance type or a piezoresistive type is used for the G sensor 24, but it is not particularly limited. A speed sensor 25 that detects the speed of the vehicle is connected to the speed I / F 15.

  Connected to the signal I / F 17 is a GPS receiver 22 (position detecting means) that detects a radio wave from a GPS satellite and receives a signal of the current position of the vehicle (GPS position information). A display device 60 is connected to the display I / F 19.

  The drive recorder 1 may be connected with a sensor for detecting engine speed, accelerator opening, brake ON / OFF, and the like as other operation data.

  The operation unit 18 is provided on the front surface of the housing 1a of the drive recorder 1 so that the driver can easily operate. The operation unit 18 includes a zero point correction button 18a described later.

  FIGS. 2A and 2B are diagrams illustrating the attachment position of the G sensor 24 and the acceleration detected when the G sensor 24 is tilted. The G sensor 24 is usually attached to a horizontal surface of the vehicle 5 as shown in FIG. The G sensor 24 may be built in the housing 1a of the drive recorder 1 or may be provided outside the housing 1a and connected to the drive recorder 1 via a cable.

  When the mounting position of the G sensor 24 is tilted by, for example, an angle θ due to an artificial operation or the like, the decomposition component g · sin θ of the gravitational acceleration g is present in the front-rear direction of the G sensor 24 as shown in FIG. Will join. Further, in the vertical direction of the G sensor 24, a decomposition component g · cos θ of the gravitational acceleration g is added. Here, the case of tilting in the front-rear direction is shown, but the same applies to the case of tilting in the left-right direction. Therefore, when the G sensor 24 is attached, the zero point correction is usually performed in order to cancel these components. In the G sensor 24, the G value also varies depending on the temperature difference between summer and winter. Furthermore, there is also a zero point correction unique to the sensor. Therefore, it is desirable to perform zero point correction periodically.

  In the zero point correction, when the G sensor 24 is in a horizontal place (0 G place), the output value of the G sensor 24 is registered as a correction value in a memory built in the G sensor 24 or a memory built in the CPU 10. Done. The G value obtained from the actual G sensor 24 is detected as a value obtained by subtracting the registered correction value.

  The operation of the drive recorder 1 having the above configuration will be described. FIG. 3 is a diagram showing an overall flow from installation to operation of the drive recorder 1. An operator (including a driver) attaches and fixes the drive recorder 1 to an appropriate location inside the vehicle 5 (T1). At this time, the G sensor 24 outside the housing 1a is attached to a horizontal surface as described above. Similarly, when incorporated in the drive recorder 1, the G sensor 24 is attached so as to be a horizontal surface.

  The driver performs various settings of the drive recorder 1 using the operation unit 18 (T2). At this time (first time point), the driver presses the zero point correction button 18a to perform the zero point correction of the G sensor 24 described above. In addition, the driver performs settings such as continuous recording or trigger recording, camera, automatic zero point correction ON / OFF, and the like.

  After performing the various settings, the driver turns on the ignition SW, actually starts the drive recorder 1 and starts operation (T3).

  When the operation is started, the drive recorder 1 executes automatic zero point correction described later (T4).

  FIG. 4 is a flowchart showing a registration procedure of a horizontal place (0G place). This processing program is stored in the ROM built in the CPU 10, and is executed by the CPU 10 after the power is turned on.

  The CPU 10 waits until the G sensor 24 becomes 0G (step S1). At 0G, the CPU 10 acquires the current position (GPS position information) of the vehicle 5 from the GPS receiver 22, and records the 0G GPS position information in the RAM 16 built in the drive recorder 1 (step S2).

  The CPU 10 determines whether or not the retention of the GPS position information of 0G has exceeded a certain time (for example, 10 minutes) (step S3). The process of step S3 is for registering a horizontal place (0G GPS position information) in a completely stopped state, and for confirming that the G place is a stable place where fluctuations in the G value have settled. It is a process performed. The certain time (predetermined time) is set to a time suitable for these determinations.

  If the predetermined time is not exceeded, the CPU 10 returns to the process of step S1. On the other hand, if the predetermined time is exceeded, the CPU 10 registers the 0G GPS position information recorded in the RAM 16 as a horizontal location in the EEPROM 12 built in the drive recorder 1 as a position on the map 30 (step S4). Thereafter, the CPU 10 ends this operation.

  FIG. 5 shows a map 30 displayed on the display device 60 in which a plurality of 0G locations (GPS position information) are registered. On the screen of the display device 60, a map 30 in which a plurality of 0G places (points) 32 are registered and a mark 35 indicating the current position of the vehicle 5 are displayed.

  FIG. 6 is a flowchart showing an automatic zero point correction procedure. This processing program is stored in the ROM in the CPU 10, and is executed by the CPU 10 after the power is turned on.

  First, the CPU 10 acquires GPS position information from the GPS receiver 22, and determines whether or not the vehicle 5 is in a horizontal place (0G place) registered in the EEPROM 12 (step S11). If not, the CPU 10 repeats the process of step 11 and waits until it moves to the registered horizontal place.

  On the other hand, when it is in a horizontal place (second time point), the CPU 10 corrects the zero point of the G sensor 24 and updates the correction value registered in the memory built in the G sensor 24 or the memory built in the CPU 10 (step). S12). The process of S12 corresponds to correction value setting means. Thereafter, the CPU 10 ends this operation.

  According to the drive recorder 1 of the present embodiment, zero point correction of acceleration can be automatically performed even after attachment to the vehicle. Thereby, the impact on the vehicle in an accident or the like can be sensed with accurate acceleration.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration that can achieve the function of the configuration of the present embodiment is applicable.

  For example, in the above embodiment, the automatic zero point correction is always performed when the vehicle 5 is in a horizontal place, but it is also possible to limit the correction. FIGS. 7A and 7B are flowcharts showing another automatic zero point correction procedure. About the same step process as FIG. 6, the description is abbreviate | omitted by attaching | subjecting the same step number.

  When limiting the automatic zero point correction, as shown in FIG. 7A, the CPU 10 determines whether or not a predetermined short period has elapsed since the previous zero point correction was performed after the power was turned on. It discriminate | determines (step S10). If the predetermined short period has not elapsed, the CPU 10 ends the operation as it is (limitation means). On the other hand, when the predetermined short period has elapsed, the CPU 10 performs the processing from step S11 described above. Thus, automatic zero point correction may be performed only when a predetermined short period has elapsed. Thereby, 0 point correction is performed more than necessary, and it is possible to reduce the load on the processing of the drive recorder 1. In addition, when the update frequency is high, automatic zero point correction may be limited.

  Conversely, when the previous zero point correction has not been performed for a while since the previous zero point correction, automatic zero point correction may be promoted. When urging automatic zero point correction, for example, as shown in FIG. 7B, the CPU 10 determines whether or not a predetermined long period has elapsed since the previous zero point correction was performed after the power was turned on. (Step S10A). When the predetermined long period has not elapsed, the CPU 10 proceeds to the process of step S11 described above.

  On the other hand, when a predetermined long period of time has elapsed, the CPU 10 displays a map (see FIG. 5) on which the horizontal location (0G location) registered in the EEPROM 12, for example, is displayed on the display device 60 (step S1). S10B), prompting the driver to perform automatic zero correction (promotion means). Thereafter, the CPU 10 proceeds to the process of step S11. As a result, it is possible to avoid a state in which zero point correction is not performed over a long period of time.

  INDUSTRIAL APPLICABILITY The present invention is useful because it can automatically perform zero point correction of acceleration even after being attached to a vehicle when performing zero point correction of an acceleration sensor.

1 Drive Recorder 1a Drive Recorder Housing 10 CPU
11, 13, 14, 15, 17, 19 Interface (I / F)
12 EEPROM
16 RAM
18 Operation unit 18a 0 point correction button 21 Recording medium 22 GPS receiver 23 Camera 24 G sensor 25 Speed sensor 30 Map (map)
320G location (point)
35 mark 60 display device

Claims (5)

An in-vehicle device that is mounted on a vehicle and performs zero-point correction of an acceleration sensor that detects acceleration of the vehicle,
Registration means for registering a point where the acceleration is 0;
Correction value setting means for setting a correction value so that the acceleration detected by the acceleration sensor has a value of 0 at the point registered by the registration means;
A vehicle-mounted device comprising: The registration unit registers a point where the correction value is set by the correction value setting unit at a first time point and the acceleration detected by the acceleration sensor is 0,
The correction value setting means sets the correction value so that the acceleration detected by the acceleration sensor becomes a value 0 at a point registered by the registration means at a second time point after the first time point. The vehicle-mounted device according to claim 1, wherein: Comprising position detecting means for detecting the position of the vehicle;
The said registration means registers the position of the said vehicle detected by the said position detection means as the said point, when the acceleration detected by the said acceleration sensor is still 0 after progress of predetermined time. Item 1. The vehicle-mounted device according to item 1 or 2.   4. The vehicle-mounted device according to claim 1, wherein the registration unit registers a plurality of points on the map where the acceleration is 0. 5. An on-vehicle device mounted on a vehicle is an acceleration correction method for performing zero-point correction of an acceleration sensor that detects acceleration of the vehicle,
A registration step of registering a point where the acceleration is 0;
A correction value setting step for setting a correction value so that the acceleration detected by the acceleration sensor becomes 0 at the point registered in the registration step;
An acceleration correction method characterized by comprising:

Images