JP2015194986A - On-vehicle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle device that determines whether a speed during travelling is appropriate taking into account a variable road state and notifies a driver of a determination result.SOLUTION: An on-vehicle device 1 comprises: a vehicle speed acquisition unit 3 that detects a current travelling speed of a vehicle; an atmospheric pressure variation sensor 4 that always continuously measures an amount of atmospheric pressure change during a travelling which is an object of determination; an up/down motion information calculation unit 5 that calculates up/down motion information on the vehicle from the measured amount of atmospheric pressure by the atmospheric pressure sensor 4; a road state estimation unit 6 that estimates a state of a road travelled by the vehicle during the travelling from the up/down motion information calculated by the up/down information calculation unit 5; an appropriate speed calculation unit 7 that calculates an appropriate speed during the travelling which is the object of determination on the road on the basis of the state of the road estimated by the road state estimation unit 6; a safety drive level determination unit 8 that determines a safety drive level on the basis of the travelling speed and the appropriate speed to output determination result information expressing a result of the determination; an interface unit 9 that notifies a driver of the determination result information to be output by the safety drive level determination unit 8.

Description

  The present invention relates to an in-vehicle device that evaluates a driving state of a vehicle.

  Ensuring safe driving of a vehicle is the most important issue for a user regardless of whether it is for personal use. However, since the user who is driving needs to respond to the surrounding situation that changes every moment, it is not possible to concentrate attention only on the speed limit and the current traveling speed of the vehicle.

  Therefore, a technique is known in which it is determined whether or not the vehicle is traveling within the speed limit by automatically detecting the speed limit of the road being traveled. For example, in Patent Document 1, whether or not the vehicle has moved from a general road to a highway by identifying whether or not the vehicle is traveling on a hill by mounting a barometric pressure sensor on an in-vehicle device and checking the map data. Alternatively, conversely, a technique is disclosed in which it is determined whether or not a transition is made from a highway to a general road, and the setting of the speed limit of the in-vehicle device is updated based on the result.

JP 2013-206419 A

  However, it is not sufficient to determine whether the vehicle is traveling at a safe speed by simply comparing the speed limit with the traveling speed. For example, the speed limit is determined for each road, and the speed limit for the up lane and the speed limit for the down lane on the slope are not distinguished. In addition, it is difficult to finely reset the speed limit with respect to temporary environmental factors such as the weather at that time. Also, even on the same road, the pavement and snowfall conditions on the road surface are not constant, so it should be considered that the safety is constantly changing even when traveling at a constant speed. Therefore, it is desirable that the in-vehicle device that performs the above determination can perform the safety determination based on the above-described road conditions that can change at any time without being limited only by the speed limit.

  The present invention has been made in view of such circumstances, and its purpose is to determine whether or not the traveling speed is appropriate based on road conditions that can change at any time, and to notify the result of the in-vehicle device Is to provide.

The present invention provides the following means in order to solve the above problems.
An in-vehicle device according to the present invention is an in-vehicle device that is mounted on a vehicle and determines a safe driving level of the vehicle, and includes a vehicle speed unit that detects a current traveling speed of the vehicle, and a travel period that is a target of the determination. An atmospheric pressure fluctuation sensor that continuously measures the atmospheric pressure fluctuation amount, a vertical movement information calculation unit that calculates vertical movement information of the vehicle from the atmospheric pressure fluctuation amount measured by the atmospheric pressure fluctuation sensor, and the vertical movement information calculation A road state estimation unit that estimates a state of a road that is traveled by the vehicle during the travel period from the vertical motion information calculated by the unit, and a road state estimated by the road state estimation unit based on the road state A determination result representing a result of the determination by determining the safe driving level based on the traveling speed and the appropriate speed, and an appropriate speed calculating unit that calculates an appropriate speed during the traveling period to be determined; A safe driving level determining section for outputting a broadcast, characterized by comprising a notification unit for notifying the determination result information output to the safe driving level determining section.
According to the in-vehicle device according to the present invention, it is possible to automatically and instantaneously determine how safe the driving at the present time is based on an appropriate speed taking into account road inclination and level difference, road surface unevenness, etc. Appropriate advice can be given to the user.

In the in-vehicle device according to the present invention, the road state estimation unit is at least one of the presence / absence and inclination of a road, the presence / absence of a step on the road and the size of the step, the presence / absence of pavement on the road surface, or the pavement state. It is characterized by estimating one.
According to the vehicle-mounted device according to the present invention, it is possible to estimate the details of the road condition and determine the safe driving level based on the result.

In the vehicle-mounted device according to the present invention, the safe driving level determination unit can set a plurality of safe driving levels based on the appropriate speed, and outputs different determination result information depending on the level of the safe driving level. It is characterized by that.
According to the vehicle-mounted device according to the present invention, the safe driving level can be determined more finely and accurately.

An in-vehicle device according to the present invention includes a position specifying unit that specifies a current position of the vehicle, a speed limit specifying unit that specifies a speed limit of a road on which the vehicle currently travels from the current position specified by the position specifying unit, , And the appropriate speed calculating unit calculates the appropriate speed using the speed limit specified by the speed limit specifying unit.
According to the vehicle-mounted device according to the present invention, the safe driving level can be determined using information such as a speed limit that is originally determined in addition to the estimated road condition.

The in-vehicle device according to the present invention is characterized in that the notification unit notifies the user of the vehicle of the determination result information via at least one of a display screen unit and an audio output unit. .
According to the vehicle-mounted device according to the present invention, the safe driving level is determined and notified to the driving user in real time, so that when the driving becomes dangerous, the driving is immediately corrected and the safe driving is maintained. Can do.

The in-vehicle device according to the present invention is connected to a management terminal that manages a vehicle equipped with the in-vehicle device via a network, and the determination result information output from the safe driving level determination unit is transmitted via the network. And a communication unit for transmitting to the management terminal.
According to the vehicle-mounted device according to the present invention, not only the user but also the person who manages the user and the vehicle can grasp the safe driving level, and can give appropriate guidance to the user based on the information.

The in-vehicle device according to the present invention is characterized in that the notification unit is a communication interface for wireless communication.
According to the vehicle-mounted device according to the present invention, the result of determining the safe driving level can be transmitted immediately, and the administrator can be immediately given attention when the driving is dangerous.

In the in-vehicle device according to the present invention, the atmospheric pressure variation sensor corresponds to a cavity having a predetermined volume, a communication hole for allowing a pressure transmission medium for transmitting atmospheric pressure to flow inside and outside the cavity, and a reference pressure that varies according to atmospheric pressure variation. And an output unit that outputs an atmospheric pressure fluctuation amount related to a differential pressure between the internal pressure representing the internal pressure of the cavity and the ambient pressure.
According to the vehicle-mounted device according to the present invention, a safe driving level can be determined based on an accurate grasp of a road condition by detecting a minute vertical movement of the vehicle by detecting a minute pressure fluctuation. Can do.

In the in-vehicle apparatus according to the present invention, the vertical motion information calculation unit is calculated by a differential pressure calculation unit that obtains a differential pressure between the internal pressure and the ambient atmospheric pressure based on the atmospheric pressure fluctuation amount, and a set value of the internal pressure and a differential pressure calculation unit The flow rate per predetermined time of the pressure transmission medium flowing inside and outside the cavity is calculated based on the pressure calculated by the differential pressure calculated by the pressure calculating unit that calculates the ambient atmospheric pressure based on the differential pressure. Based on the flow rate calculation unit to be calculated, the flow rate calculated by the flow rate calculation unit and the volume of the cavity, the internal pressure after a predetermined time is calculated, and the set value of the internal pressure used in the pressure calculation unit is updated with the calculated internal pressure And an internal pressure updating unit.
According to the vehicle-mounted device according to the present invention, it is possible to accurately detect minute fluctuations in atmospheric pressure to calculate vertical movement information, and to accurately determine a safe driving level based on the information.

The in-vehicle device according to the present invention includes a cantilever that is provided so as to block the opening surface of the cavity excluding the communication hole, and that bends and deforms in accordance with the differential pressure, and the output unit has a bending deformation amount of the cantilever. It is characterized in that it outputs an atmospheric pressure fluctuation amount corresponding to.
According to the vehicle-mounted device according to the present invention, a minute vertical movement of the vehicle can be detected by outputting a signal corresponding to a slight change in atmospheric pressure, and an accurate safe driving level can be determined based on the detection.

  According to the in-vehicle device according to the present invention, the user or the administrator can always compare the appropriate speed with the current speed during traveling and notify the safe driving level based on the result. Can be ensured.

It is a block diagram which shows the structure of the vehicle-mounted apparatus 1 concerning 1st Embodiment of this invention. It is a schematic diagram which shows the cross-sectional structure of the atmospheric | air pressure fluctuation sensor 4 concerning 1st Embodiment of this invention. It is a flowchart which shows the characteristic operation | movement of the vehicle-mounted apparatus 1 concerning 1st Embodiment of this invention. (A) (b) It is a figure which shows the example which converted the height variation data in 1st Embodiment of this invention into the frequency component. It is a flowchart which shows the variation part of characteristic operation | movement of the vehicle-mounted apparatus 1 concerning 1st Embodiment of this invention. It is a block diagram which shows the structure of the vehicle-mounted apparatus 21 concerning 2nd Embodiment of this invention. It is a flowchart which shows the characteristic operation | movement of the vehicle-mounted apparatus 21 concerning 2nd Embodiment of this invention. 3 is a data structure diagram showing a structure of map data 23. FIG. It is a block diagram which shows the structure of the vehicle safety management system 50 concerning 3rd Embodiment of this invention. It is a block diagram which shows the structure of the vehicle-mounted apparatus 41a concerning 3rd Embodiment of this invention. It is a figure which shows the example of the information displayed on the display part which abbreviate | omitted illustration of the manager apparatus 61 in 3rd Embodiment of this invention. It is a figure which shows another example of the information displayed on the display part which abbreviate | omitted illustration of the manager apparatus 61 in 3rd Embodiment of this invention. It is a top view which shows the structure of the pressure sensor 81 in 4th Embodiment of this invention. It is sectional drawing of the pressure sensor 81 along the AA line shown in FIG. It is a figure which shows an example of the output of the pressure sensor 81 shown in FIG. It is a figure which shows an example of the output of the pressure sensor 81 shown in FIG. It is explanatory drawing which shows the flow of the process which calculates the moving amount | distance of the up-down direction which the vertical motion information calculation part 5 shown in FIG. 1 performs.

Hereinafter, an embodiment of an in-vehicle device according to the present invention will be described with reference to the drawings.
(First embodiment)
1st Embodiment of the vehicle-mounted apparatus concerning this invention is described using FIGS.
FIG. 1 is a block diagram showing a configuration of an in-vehicle device 1 according to the first embodiment of the present invention. FIG. 2 is a schematic diagram showing a cross-sectional structure of the atmospheric pressure fluctuation sensor 4. FIG. 3 is a flowchart showing the characteristic operation of the in-vehicle device 1. FIGS. 4A and 4B are diagrams showing an example in which height variation data is converted into frequency components. FIG. 5 is a flowchart showing variations of the characteristic operation of the in-vehicle device 1.

"About the configuration of each part of the in-vehicle device"
The in-vehicle device 1 according to the present embodiment is installed, for example, inside a vehicle used by a user (inside the vehicle) and in the vicinity of a driver's seat so that the user can easily operate. The in-vehicle device 1 includes a control unit 2 for comprehensively controlling each unit of the in-vehicle device 1, a vehicle speed acquisition unit 3 for acquiring vehicle speed data, a pressure fluctuation sensor 4 for detecting the amount of pressure fluctuation of the vehicle, From the pressure fluctuation data representing the pressure fluctuation amount, the vertical motion information calculation unit 5 that calculates the height fluctuation amount of the vehicle, the road state estimation unit 6 that estimates the road state from the height fluctuation amount, and safe driving from the road state. An appropriate speed calculation unit 7 that calculates an appropriate speed for the vehicle, a safe driving level determination unit 8 that determines a safe driving level indicating how safe the driving is based on a comparison between the appropriate speed and the vehicle speed, and a user And an interface unit 9 for inputting various setting information such as starting and stopping of the in-vehicle device 1 and for warning the user of the safe driving level.

  For example, the control unit 2 includes a CPU, a RAM, a ROM, and the like (not shown), and the CPU expands and executes various control programs stored in the ROM on the RAM, so that the vehicle is mounted on the vehicle. It is a central control unit that controls each unit and the whole of the apparatus 1.

  The vehicle speed acquisition unit 3 is connected to a computer (not shown) mounted on the vehicle, and is configured to acquire vehicle speed data representing the current vehicle speed by obtaining a vehicle speed pulse signal from the computer.

  The atmospheric pressure fluctuation sensor 4 is a sensor that continuously measures the atmospheric pressure fluctuation amount during the traveling period of the vehicle. For example, as shown in FIG. 2, the atmospheric pressure fluctuation sensor 4 is a sensor having a cavity 10 and a thin plate-like cantilever 11 which is arranged so as to cover the cavity 10 and is fixed at one end and free at the other end. is there. The cantilever 11 covers almost all of the entrance of the cavity 10 (the upper end side in FIG. 2), but leaves a slight gap 12 around it. In the atmospheric pressure variation sensor 4 having such a structure, when the ambient atmospheric pressure varies, the cantilever 11 is deformed by a pressure difference between the atmospheric pressure inside the cavity 10 and the ambient atmospheric pressure. Therefore, the atmospheric pressure fluctuation sensor 4 can output the deformation of the cantilever 11 as an electric signal by forming the piezoresistive element 13 in the deformed portion of the cantilever 11. Output as electrical signal (pressure fluctuation data). The pressure fluctuation sensor 4 is not limited to the sensor having the above principle / structure, and any sensor based on any principle / structure can be used as long as it has a function of quantitatively measuring the surrounding air pressure fluctuation. It may be used.

  The vertical movement information calculation unit 5 receives the atmospheric pressure fluctuation data output from the atmospheric pressure fluctuation sensor 4, and uses the predetermined conversion method to convert the atmospheric pressure fluctuation data into the height fluctuation amount along the vehicle's gravitational acceleration direction (vertical movement information). Convert to Here, since the atmospheric pressure depends on the position along the direction of gravity, when the vehicle moves up and down, the corresponding atmospheric pressure fluctuation occurs. Therefore, the vertical motion information calculation unit 5 can calculate the height fluctuation amount of the vehicle by substituting the atmospheric pressure fluctuation amount related to the atmospheric pressure fluctuation data into a predetermined conversion formula or referring to a predetermined atmospheric pressure altitude correspondence table. Here, the predetermined conversion formula is that the measured atmospheric pressure at an arbitrary time t1 is P1, and the measured atmospheric pressure at a time t2 different from t1 is P2, and the difference between the vehicle height at t1 and the vehicle height at t2 (height fluctuation) (Quantity) Δh is an expression for obtaining P1 and P2, and for example, an expression such as expression (1) is known.

Δh = 18410.0 × (log10P1-log10P2) (1)
Here, the unit of the height fluctuation amount Δh is meter [m], and the unit of the measured atmospheric pressures P1 and P2 is hectopascal [hPa]. Note that the height fluctuation amount of the vehicle can be calculated from the atmospheric pressure fluctuation amount by preparing a barometric altitude correspondence table incorporating temperature information at that time in advance and referring to the table.

  The road state estimation unit 6 estimates the state of the road based on the vertical movement information calculated by the vertical movement information calculation unit 5. The vertical movement of the vehicle occurs due to various causes. For example, road surface unevenness, steps, road inclination, and the like. Of these, the unevenness of the road surface causes a fluctuation in height of several millimeters or more from the road surface, such as a break in a paved road and gravel on the road surface. Further, the level difference causes a height fluctuation of about several centimeters or more that occurs when a vehicle rides on a sidewalk or parking lot from a roadway. Furthermore, the inclination of the road causes a height fluctuation of about several meters or more that occurs when the road itself is a slope. In other words, the vertical movement of the vehicle caused by each factor has a difference in the height fluctuation amount on the scale, and the difference in the scale appears as a frequency difference in the frequency analysis.

  Therefore, the road state estimation part 6 can be easily separated into frequency components for each factor of vertical movement by converting the height fluctuation data into frequency components. Here, FIGS. 4A and 4B are examples in which the height variation data is converted into frequency components. The horizontal axis f represents frequency, and the vertical axis A represents signal intensity. The frequency component of the height variation data is interpreted by dividing into three regions, a low frequency region, a medium frequency region, and a high frequency region, by the first frequency threshold f1 and the second frequency threshold f2. The presence or absence of a peak is determined by the magnitude relationship between the signal intensity and the intensity threshold value At. FIG. 4A shows an example in which a peak p1 is observed in the low frequency region and a peak p2 is observed in the high frequency region. The presence of low frequency components suggests that the road is a slope. The presence of high frequency components suggests that there are fine irregularities on the road surface. Further, the absence of the medium frequency component suggests that there is no step such as riding on the sidewalk or parking lot from the above-described roadway. From these things, the road state estimation part 6 can estimate that it is drive | working the slope with fine unevenness | corrugations, such as gravel, in the case of Fig.4 (a). In FIG. 4B, a peak p3 is observed in the middle frequency region, and the signal strength in other frequency regions is low. From these things, in the case of FIG.4 (b), the road state estimation part 6 can estimate that there exists a level | step difference, such as boarding from the above-mentioned roadway to a sidewalk or a parking lot in the road surface paved on the flat ground. The road state estimation unit 6 outputs road state information representing the estimated road state to the appropriate speed calculation unit 7.

  The appropriate speed calculation unit 7 calculates an appropriate speed according to the road state based on the estimation result (road state information) of the road state estimated by the road state estimation unit 6. Whether or not the vehicle is being driven safely should not be determined only from the speed and the speed limit of the road, but more preferably from the detailed unevenness information and inclination information of the road surface. For example, when the road surface is extremely uneven, the tire grip may be insufficient. On the other hand, when the road surface is very uneven, the vehicle may be unstable. In addition, when the road surface has a step, the traveling of the vehicle becomes unstable.

  Therefore, the appropriate speed calculation unit 7 calculates the appropriate speed when traveling on a specific road in consideration of road conditions such as unevenness and inclination of the road surface. Here, the relationship between the appropriate speed and each road state is created as a correspondence table obtained in advance by experiments, and the correspondence table is stored in the storage area of the appropriate speed calculation unit 7. The correspondence table is, for example, “appropriate speed is 80% of the speed limit” for road conditions with “large unevenness and large slope”, and “speed limit for road conditions with“ fine unevenness and small slope ”. The correspondence relationship between the road state and the appropriate speed determined according to each road state is stored. That is, the appropriate speed calculation unit 7 calculates an appropriate speed from the vehicle speed information and the vertical movement information using the correspondence table, and sends the result to the control unit 2. The item corresponding to the road condition stored in the correspondence table is not limited to the appropriate speed itself (the appropriate speed value itself), and may be, for example, a deceleration amount or a deceleration rate with respect to the limited speed. That is, by setting in advance the speed limit of the road on which the user is scheduled to travel via the interface unit 9, the appropriate speed calculation unit 7 can obtain the deceleration amount corresponding to the road state or the like when the road state information is acquired. The speed reduction rate may be extracted from the correspondence table, and the appropriate speed may be calculated by performing four arithmetic operations on the speed limit using the speed reduction amount and the speed reduction rate.

  The safe driving level determination unit 8 determines a safe driving level indicating how safe the driving is by comparing the appropriate speed calculated by the appropriate speed calculation unit 7 and the vehicle speed acquired by the vehicle speed acquisition unit 3. . Specifically, the safe driving level determination unit 8 compares the vehicle speed with the appropriate speed, and the safe driving level is “safe” if the vehicle speed is less than the appropriate speed, and “danger” if the vehicle speed exceeds the appropriate speed. It is determined that there is, and a determination result (determination result information) is sent to the control unit 2.

  Further, the safe driving level determination unit 8 may be configured to be able to set a safe driving level in a plurality of stages and to output different determination results depending on the level of the safe driving level. That is, the safe driving level determination unit 8 determines a more detailed safe driving level by setting a medium dangerous speed and a high dangerous speed in addition to the appropriate speed in advance.

  Here, the medium danger speed and the high danger speed are, for example, a speed value obtained by multiplying an appropriate speed by a predetermined magnification (medium danger magnification <high danger magnification), or a predetermined speed value (medium danger The speed value is the sum of (speed value <speed value for high danger). The medium critical speed and the high critical speed may be obtained simultaneously with the appropriate speed by adding a predetermined value (for example, 10 km / h) when the appropriate speed calculation unit 7 calculates the appropriate speed.

  In this case, the safe driving level determination unit 8 determines “very dangerous” when the vehicle speed exceeds the high dangerous speed, and “very dangerous” when the vehicle speed is below the high dangerous speed and exceeds the medium dangerous speed. If it is below the medium critical speed and exceeds the appropriate speed, it is determined as “danger”.

  The interface unit 9 includes, for example, various selection / decision buttons, a monitor having a touch panel function, a speaker, and the like. The interface unit 9 causes the user to execute input processing of various setting information such as starting and stopping of the in-vehicle device 1 and reporting (warning) the safe driving level through a monitor and a speaker.

About safe driving level judgment and notification processing
Next, the safe driving level determination / notification process realized by the in-vehicle device 1 will be described with reference to the flowchart of FIG. 3.
First, the user operates the interface unit 9 to start a safe driving level determination function by the in-vehicle device 1. The safe driving level determination function may be set so as to be always executed while the engine is being driven. Then, the control part 2 acquires the present vehicle speed from the vehicle speed acquisition part 3 (step S1). Next, the control unit 2 activates the atmospheric pressure fluctuation sensor 4 and obtains atmospheric pressure fluctuation data from the atmospheric pressure fluctuation sensor 4 (step S2). The control unit 2 sends the atmospheric pressure fluctuation data acquired in step S <b> 2 to the vertical movement information calculation unit 5. Next, the vertical motion information calculation unit 5 calculates the vertical motion information based on the above-described conversion formula, and outputs it to the control unit 2 (step S3).

Next, the road state estimation unit 6 that has acquired the vertical movement information from the control unit 2 estimates the road state based on the vertical movement information, and outputs the estimation result to the control unit (step S4).
Next, the appropriate speed calculation unit 7 that has acquired the estimation result of the road state from the control unit 2 calculates an appropriate speed according to the road state, and outputs the calculated appropriate speed to the control unit 2 (step S5).

  Next, the control unit 2 outputs the vehicle speed acquired in step S1 and the appropriate speed acquired in step S5 to the safe driving level determination unit 8. Then, the safe driving level determination unit 8 compares the vehicle speed with the appropriate speed, and the safe driving level is “safe” if the vehicle speed is less than the appropriate speed, and “danger” if the vehicle speed exceeds the appropriate speed. It determines with there and sends a determination result to the control part 2 (step S6).

  Note that the safe driving level determination unit 8 may further execute processes as shown in S11 to S15 of FIG. 5 after the comparison of the magnitude relationship between the vehicle speed and the appropriate speed described in step S6. Specifically, the safe driving level determination unit 8 previously sets a medium dangerous speed (> proper speed) and a high dangerous speed (> medium dangerous speed, <limit speed) in addition to the appropriate speed. Then, the safe driving level determination unit 8 determines the magnitude relationship between the vehicle speed and the high dangerous speed (step S11), and if it is determined that the high dangerous speed is exceeded (step S11; Y), “very dangerous” Is determined (step S13). On the other hand, when the safe driving level determination unit 8 determines that the high critical speed is not exceeded in step S11 (step S11; N), the safe driving level determination unit 8 determines the magnitude relationship with the medium dangerous speed (step S12). When the safe driving level determination unit 8 determines that the medium dangerous speed is exceeded in step S12 (step S12; Y), the safe driving level determination unit 8 determines that it is “very dangerous” (step S14) and exceeds the medium dangerous speed. If it is determined that it has not been performed (step S12; N), it is determined as “danger” (step S15). Next, when the determined safe driving level is not “safe”, the control unit that has acquired the determination result by the safe driving level determining unit 8 notifies the user of a warning via the interface unit (step S7). Note that the notification to the user may be a text or image on the screen, or a warning sound or sound from a speaker.

  Therefore, when the user receives the warning, the user can always continue the safe driving by reducing the speed until the warning is not issued. The warning operation to the user after the safe driving judgment from the pressure fluctuation measurement continues to drive until the driving is in a safe state, so even if the user has run dangerously, the warning is given immediately be able to.

(Second Embodiment)
A second embodiment of the in-vehicle device according to the present invention will be described with reference to FIGS.
FIG. 6 is a block diagram showing the configuration of the in-vehicle device 21 according to the second embodiment of the present invention. FIG. 7 is a flowchart showing the characteristic operation of the in-vehicle device 21. Of the configuration shown in FIG. 6 and the steps shown in FIG. 7, the same configurations and steps as those in FIG. 1 and FIG.

  The difference of this embodiment from the first embodiment is that it includes a position acquisition unit 22 that acquires the current position of the vehicle on which the in-vehicle device 21 is mounted, and a map data storage unit 24 that stores map data 23. . Both the position acquisition unit 22 and the map data storage unit 24 use functions possessed by a general car navigation device.

The position acquisition unit 22 includes a GPS receiver that receives a GPS signal transmitted from a GPS satellite, and generates current position data representing the current position of the vehicle (on-vehicle device 21).
The map data storage unit 24 is composed of a hard disk drive or the like and stores the map data 23.

  The map data 23 has a data structure including road data 31, background data 32, character data 33, and guidance data 34 as shown in FIG. The road data 31 is data used for displaying a map or displaying the current position. The background data 32 and the character data 33 are data used to display a background and characters when displaying a map, respectively. The guidance data 34 is data used for route guidance such as the name of an intersection. Here, the road data 31 holds information regarding the speed limit of each road.

About safe driving level judgment and notification processing
Next, the safe driving level determination / notification process realized by the in-vehicle device 21 will be described with reference to the flowchart of FIG. Here, the processing from step S1 to step S4 is the same as the processing shown in FIG. In the present embodiment, after the road state estimation unit 6 estimates the road state in step S4, the position acquisition unit 22 acquires the current position of the vehicle and transmits it to the control unit 2 (step S31). Next, the control unit 2 refers to the map data 23 stored in the map data storage unit 24 and grasps the position on the map data 23 corresponding to the current position of the vehicle and the speed limit of the road at the position ( Step S32). The appropriate speed calculation unit 7 calculates an appropriate speed from the road state and the speed limit (step S33). For example, when it is estimated that the road state has a small inclination and few steps and road surface unevenness, the appropriate speed calculation unit 7 sets the appropriate speed to be the same as the speed limit. In addition, when the road has many steps and unevenness, the appropriate speed calculation unit 7 sets the appropriate speed to a value lower than the speed limit according to the amount. Furthermore, the appropriate speed calculation unit 7 sets the appropriate speed to a lower value when the road is inclined.

  Next, the safe driving level determination unit 8 compares the vehicle speed with the appropriate speed (step S6). And the control part 2 issues a warning with respect to a user, when the vehicle speed exceeds the appropriate speed via the user interface part 9 (step S34). The warning in the present embodiment is issued based on the speed limit. For example, “Although the speed limit is 50 km, it is desirable to suppress the speed in the section that is currently running”. It becomes a warning. When the user passes through a dangerous section and enters a section having no slope or level difference, the user is notified that the warning has become invalid.

  By carrying out the present invention in this way, it is possible to provide highly accurate advice that constantly evaluates safety even when traveling on the same road, issues warnings as necessary, and does not issue unnecessary warnings. It becomes.

(Third embodiment)
An embodiment of a vehicle safety management system 50 using an in-vehicle device according to the present invention will be described with reference to FIGS.
FIG. 9 is a block diagram showing a configuration of a vehicle safety management system 50 according to the third embodiment of the present invention. A plurality of vehicles are registered in the vehicle safety management system 50. One vehicle has an in-vehicle device 41a, and another vehicle has an in-vehicle device 41b. One in-vehicle device is installed in every vehicle. The vehicle safety management system 50 includes a data management server 51 that performs data communication with these in-vehicle devices 41a, 41b,..., And an administrator device 61 that is a terminal used by an administrator who manages the vehicle.

FIG. 10 is a block diagram showing the configuration of the in-vehicle device 41a according to the present embodiment. The on-vehicle devices 41b, 41c,... Have basically the same configuration as the on-vehicle device 41a, and thus description thereof is omitted. Moreover, the same code | symbol is provided to the same part as the vehicle-mounted apparatus 1 which concerns on 1st Embodiment shown in FIG. 1 among the structures of the vehicle-mounted apparatus 41a, and description is abbreviate | omitted.
The in-vehicle device 41a according to the present embodiment is different from the in-vehicle device 1 in that a driver data storage unit 73 that stores driver data 71 and an in-vehicle communication unit 72 are further provided.

  The driver data storage unit 73 is configured by a hard disk drive or the like, and stores driver data 71. The driver data 71 is an ID number given to each user (driver of each vehicle) in order to identify a user who is currently driving the vehicle (using the in-vehicle device 41a). Here, it is assumed that the vehicle according to the present embodiment is operated by being switched and operated by a plurality of users, for example, in the transportation industry. Therefore, the driver data 71 is used for uniquely identifying who the current user of each vehicle is. Here, when the user starts driving the vehicle, his / her ID information is stored in the driver data 71 by inputting his / her ID number to the interface unit 9 of the in-vehicle device 41a provided in the vehicle.

  The in-vehicle communication unit 72 is a wired / wireless communication interface for transmitting and receiving data to and from the data management server 51, and the determination result of the safe driving level by the safe driving level determination unit 8 together with the vehicle ID and the driver data 71. The data is transmitted to the data management server 51.

  The data management server 51 includes a server control unit (not shown) that performs overall control of the components of the data management server 51, a management server storage unit 56 that stores various data, an in-vehicle device 41a to 41x, and an administrator device 61. And a server communication unit 55 for performing data communication.

  The management server storage unit 56 is a database configured with, for example, a hard disk drive or the like, and stores a plurality of records configured to include data items such as vehicle ID data 52, driver data 53, and safe driving level data 54. . Here, the vehicle ID data 52 is data relating to an ID number given to each vehicle on which the in-vehicle devices 41a to 41x are mounted, and the driver data 53 is an ID given to each user (driver of each vehicle). The safe driving level data 54 is data related to the determination result of the safe driving level determined by each of the in-vehicle devices 41a to 41x.

  The server communication unit 55 is a wired / wireless communication interface for transmitting / receiving data to / from the in-vehicle devices 41 a to 41 x and the administrator device 61. The server communication unit 55 receives the vehicle ID, the driver data 71, and the determination result of the safe driving level from the in-vehicle communication unit 72 of the in-vehicle device 41a. In addition, the server communication unit 55 transmits the vehicle ID data 52, the driver data 53, the safe driving level data 54, and the like stored in the management server storage unit 56 to the manager device 61.

  The server control unit includes, for example, a CPU, a RAM, a ROM, and the like (not shown), and the CPU develops various control programs stored in the ROM on the RAM and executes the data. It is a central control unit that controls each unit and the entire management server 51. Here, the server control unit acquires the vehicle ID, the driver data 71, and the determination result of the safe driving level from the server communication unit 55. Then, the server control unit refers to the database of the management server storage unit 5 with the acquired vehicle ID and driver data 71 for the corresponding vehicle ID data 52 and driver data 53, and the safe driving level data 54 The administrator who manages the vehicle and the user who performs the postscript correction accesses the data management server 51 (management server storage unit 5) by using the administrator device 61, thereby grasping whether each vehicle is currently safely driving. can do.

  The administrator device 61 is a terminal such as a personal computer, for example. Although not shown, a terminal control unit that performs overall control of the administrator device 61, a communication interface for communicating with the data management server 51, a monitor The display unit includes a device, a terminal storage unit that stores vehicle ID data, and the like.

  Here, the terminal control unit of the manager device 61 transmits the vehicle ID data and the driver data for which the safe driving level is desired to be grasped to the data management server 51 via the server communication unit 55, whereby the server control unit manages the data. The corresponding vehicle ID data 52, driver data 53, and safe driving level data 54 are returned from the server storage unit 5 to the terminal control unit. When the terminal control unit acquires the vehicle ID data 52, the driver data 53, and the safe driving level data 54, the terminal control unit performs predetermined processing on the acquired data, for example, as shown in FIG. The determination result of the safe driving level corresponding to each vehicle is displayed via the display unit. Here, in FIG. 11, the vertical axis represents the vehicle ID of each vehicle, and the horizontal axis represents the current time (when vehicle ID data 52, driver data 53, and safe driving level data 54 are acquired from the data management server 51. Represents safe driving level. In the example of FIG. 11, the vehicles set with the vehicle ID 01 and the vehicle ID 02 indicate that the vehicle is safely driven at the present time, but it is understood that the vehicle set with the vehicle ID 03 is in a dangerous driving state. In FIG. 11, it is shown that the vehicle set with the vehicle ID 04 is stopped. Therefore, the user (administrator) of the administrator device 61 contacts the vehicle set with the vehicle ID 03 by a method such as wireless communication after seeing the result displayed on such a display unit, and the current driver Can be alerted to drive safely. Moreover, it is also possible to comprise so that a terminal control part may perform such an alerting process automatically. That is, when the vehicle control unit 51 acquires the vehicle ID data 52, the driver data 53, and the safe driving level data 54 from the data management server 51, the terminal control unit determines whether or not the safe driving level of each vehicle is below a predetermined level. To do. When the terminal control unit determines that the current driver is not satisfied, the terminal control unit transmits a warning message to the in-vehicle device 41a via the communication interface of the administrator device 61 and the interface unit 9 of the in-vehicle device 41a. You can also call attention to.

  Here, the determination result of the safe driving level displayed on the display unit by the manager device 61 may be as illustrated in FIG. In FIG. 12, the vertical axis indicates the safe driving level, and the horizontal axis indicates time. Moreover, each line of the line graph in FIG. 12 shows the time change of the safe driving level of the vehicle in which the vehicle IDs 01 to 04 are set. In this figure, the vehicle set with the vehicle ID01 stably performs safe driving, but the vehicle set with the vehicle ID02 is unstable and gradually changes in a dangerous direction. . In addition, the vehicle set with the vehicle ID 03 is always in a dangerous driving state. Here, the vehicle ID 04 indicates that the vehicle has stopped until an intermediate time. In this way, by confirming the time change of the safe driving level of each vehicle, it is possible to make a call to call attention to the vehicle as necessary. In addition, by reflecting the safe driving level in the business evaluation for each user, it becomes possible to motivate all users more strongly for safe driving.

(Fourth embodiment)
In the embodiment described above, a micro pressure sensor having a cantilever made of a thin film manufactured by a MEMS (MicroElectro Mechanical Systems) process can be used as the atmospheric pressure fluctuation sensor 4. The structure and signal processing method will be described below.

(Structure of pressure sensor)
FIG. 13 is a plan view showing a configuration of a pressure sensor 81 as the atmospheric pressure fluctuation sensor 4. FIG. 14 is a cross-sectional view of the pressure sensor 81 along the line AA shown in FIG.
The pressure sensor 81 is a sensor that detects pressure fluctuations in a predetermined frequency band (for example, 0.05 Hz to 10 kHz), and includes a sensor main body 83, an atmospheric pressure measurement cantilever 84, a lid portion 312, and a displacement measurement portion 85. And have.

  The sensor body 83 has a cavity 310 therein. The sensor body 83 divides the cavity 310 and is disposed on the first portion 83-1 and the first portion 83-1, and includes a silicon support layer 82a, a silicon oxide film, and the like. And a second portion 83-2 made of the oxide layer 82b.

  The atmospheric pressure measurement cantilever 84 can be formed, for example, by processing an SOI substrate 82 in which a silicon support layer 82a, an oxide layer 82b such as a silicon oxide film, and a silicon active layer 82c are thermally bonded.

The atmospheric pressure measurement cantilever 84 is formed of a silicon active layer 82c in the SOI substrate 82, and is formed by cutting out a gap 313 formed in a U shape in plan view from the silicon active layer 82c on the flat plate. Here, the gap 313 (communication hole) is a gap formed between the atmospheric pressure measurement cantilever 84 and the inner wall of the sensor body 83, and allows air inside and outside the cavity 310 to circulate.
Accordingly, the atmospheric pressure measurement cantilever 84 has a cantilever structure in which the proximal end portion 84a is a fixed end and the distal end portion 84b is a free end.

  The atmospheric pressure measurement cantilever 84 is disposed so as to surround the upper surface of the cavity 310 formed in the sensor main body 83. That is, the atmospheric pressure measurement cantilever 84 substantially closes the opening of the cavity 310.

  The atmospheric pressure measuring cantilever 84 is cantilevered so as to close the cavity 310 by being integrally fixed on the second portion 83-2 of the sensor body 83 via the base end portion 84a.

  Thereby, the pressure measuring cantilever 84 can be bent and deformed according to the pressure difference between the inside and the outside of the cavity 310 with the base end portion 84a as the center. Here, since the base end portion 84a of the atmospheric pressure measurement cantilever 84 is formed with a U-shaped through-hole 315 in plan view, the atmospheric pressure measurement cantilever 84 is easily bent and deformed. However, the shape of the through-hole 315 is not limited to the U-shape as long as it can easily be bent and deformed by the atmospheric pressure measuring cantilever 84.

  The lid 312 is disposed so as to surround the pressure measurement cantilever 84 via the gap 313 in plan view. The lid 312 is composed of a silicon active layer 82c. The lid 312 is disposed above the cavity 310.

The displacement measuring unit 85 (output unit) includes a piezoresistor 320 whose electric resistance value changes in accordance with the deflection amount (displacement amount) of the atmospheric pressure measurement cantilever 84 and a detection circuit 322 that extracts the electric resistance value change. . As shown in FIG. 11, the piezoresistors 320 are arranged in pairs on both sides of the through hole 315 in the short direction of the atmospheric pressure measurement cantilever 84.
The pair of piezoresistors 320 are electrically connected to each other via a wiring portion 321 made of a conductive material.

  The overall shape including the wiring portion 321 and the piezoresistor 320 may be, for example, a U shape in plan view. The piezoresistor 320 is electrically connected to a detection circuit 322 that measures the displacement of the atmospheric pressure measurement cantilever 84 based on the change in the electric resistance value of the piezoresistor 320.

  In the displacement measuring section 85 configured as described above, a current generated when a predetermined voltage is applied to the piezoresistor 320 through the detection circuit 322 wraps around the through-hole 315 so that the wiring section 321 is connected from one piezoresistor 320. To the other piezoresistor 320.

  For this reason, the detection circuit 322 can take out the change in the electric resistance value of the piezoresistor 320 that changes according to the displacement (deflection deformation) of the atmospheric pressure measurement cantilever 84 as an electrical output signal.

  Therefore, the displacement measuring unit 85 can measure the displacement of the atmospheric pressure measuring cantilever 84 based on the output signal (sensor output) of the detection circuit 322. Since the atmospheric pressure measurement cantilever 84 is deformed based on the differential pressure between the inside and the outside of the cavity 310, it is possible to take out the change in the atmospheric pressure outside the cavity 310 as an output signal.

  The piezoresistor 320 is formed by doping the silicon active layer 82c with a dopant (impurity) such as phosphorus by various methods such as ion implantation and diffusion.

  In addition, the pair of piezoresistors 320 are configured to be electrically connected only by the wiring portion 321. For this reason, although not shown, the silicon active layer 82 c located around the atmospheric pressure measurement cantilever 84 is etched so that both the piezoresistors 320 do not conduct except at the wiring portion 321.

Further, a piezoelectric thin film may be used in place of the piezoresistor 320.
In this case, an electromotive force is generated according to the stress applied to the proximal end portion 84a of the atmospheric pressure measurement cantilever 84, and the displacement of the atmospheric pressure measurement cantilever 84 can be detected by detecting this electromotive force.

(Pressure sensor operation)
Next, an operation when the pressure sensor 81 described above detects a minute pressure fluctuation will be described with reference to FIG. 15 and FIG. 16.
FIG. 15 is a diagram schematically illustrating an example of the output of the pressure sensor 81. FIG. 15A is a diagram showing the change with time of the pressure inside and outside the cavity, and FIG. 15B is a diagram showing the change with time of the output of the pressure sensor 81.

  FIG. 16 is a cross-sectional view schematically showing an example of the operation of the pressure sensor 81. FIG. 16A shows a cross-sectional view of the pressure sensor in the initial state, and FIG. 16B shows a cross-sectional view of the pressure sensor when the pressure outside the cavity is higher than the internal pressure. C) shows a cross-sectional view of the pressure sensor when the pressure inside and outside the cavity returns to the same pressure. In FIG. 16, the detection circuit 322 constituting the pressure sensor 81 is not shown.

  First, as in period A shown in FIG. 15A, the difference between the pressure outside the cavity 310 (hereinafter “external pressure Pout”) and the pressure inside the cavity 310 (hereinafter “internal pressure Pin”) is zero. In this case, as shown in FIG. 16A, the pressure measuring cantilever 84 is not bent and deformed.

  Here, as in the period B after time t1 shown in FIG. 15A, for example, when the external pressure Pout rises stepwise, a differential pressure is generated between the outside and the inside of the cavity 310, and therefore FIG. ), The barometric pressure measuring cantilever 84 is bent and deformed toward the inside of the cavity 310.

  Then, distortion occurs in the piezoresistor 320 in accordance with the bending deformation of the atmospheric pressure measuring cantilever 84, and the electric resistance value changes, so that the output signal of the pressure sensor 81 increases as shown in FIG.

  Further, in the time after the increase of the external pressure Pout, the pressure transmission medium flows from the outside to the inside of the cavity 310 through the gap 313. For this reason, as shown in FIG. 15A, the internal pressure Pin rises with time, with a response that is slower than the fluctuation of the external pressure Pout while being delayed from the external pressure Pout.

  As a result, the internal pressure Pin gradually approaches the external pressure Pout, so that the pressure between the outside and the inside of the cavity 310 is in an equilibrium state, and the bending of the atmospheric pressure measuring cantilever 84 gradually decreases, as shown in FIG. The output signal gradually decreases.

Then, when the internal pressure Pin becomes the same as the external pressure Pout as in the period C after time t2 shown in FIG. 15A, the bending deformation of the atmospheric pressure measuring cantilever 84 is eliminated as shown in FIG. To return to the original state. Further, as shown in FIG. 15B, the output signal of the pressure sensor 81 also returns to zero.
Thus, by monitoring the fluctuation of the output signal based on the displacement of the atmospheric pressure measurement cantilever 84, the pressure fluctuation outside the cavity 310 can be detected.

  In particular, since the barometric pressure measuring cantilever 84 can be formed by a semiconductor process technique using the silicon active layer 82c of the SOI substrate 82, it is easy to make it thinner (for example, several tens to several hundreds nm) than a conventional piezoelectric element. Therefore, it is possible to detect minute pressure fluctuations with high accuracy.

  However, although the above-described output signal indicates an increase or decrease in the pressure of the outside air, it does not simply indicate a time variation (pressure gradient with respect to the time axis) of the pressure of the outside air. Specifically, the output signal increasing tendency in the period B1 in FIG. 15 indicates that the actual pressure to be measured (external pressure Pout) increases, but the output signal decreasing tendency in the period B2 is as described above. This is due to the increase of the internal pressure Pin due to the flow of the pressure transmission medium from the outside to the inside of the cavity 310, and suggests that the pressure of the actual measurement object will decrease even though it has not changed over time. . For this reason, even if a simple integration process or the like is performed on the output signal, it is impossible to grasp the time change of the pressure to be measured (time change of the external pressure). Further, the maximum value of the output signal shown in FIG. 15 at the boundary between the period B1 and the period B2 roughly indicates the pressure gradient with respect to the time axis, but is not necessarily the pressure gradient value. This is because the maximum value of the output signal changes depending on the time when the pressure fluctuation occurs. On the other hand, when the pressure of the outside air increases or decreases even slightly, an output signal corresponding to the direction in which the pressure changes (increase or decrease) can be obtained.

  As described above, the pressure sensor 81 can obtain an output signal only when the pressure of the outside air fluctuates. Furthermore, since the cantilever is thin, it can output even a slight pressure change. For this reason, even if the vehicle goes up and down a step of several tens of centimeters, the vertical movement can be detected from the change in atmospheric pressure.

(Vertical movement amount / Calculation method)
Next, in the present embodiment using the pressure sensor 81, a procedure in which the vertical movement information calculation unit 5 calculates the vertical movement amount of the vehicle from the output of the pressure sensor 81 will be described with reference to the flowchart of FIG.

  First, when an output signal is input from the pressure sensor 81 (step S701), the vertical motion information calculation unit 5 stores N values of output signals from the pressure sensor 81 for each predetermined time Δt (not shown). (Step S702).

  Next, the vertical motion information calculation unit 5 obtains differential pressures ΔP and N (ΔP (1 to N)) applied to the atmospheric pressure measurement cantilever corresponding to the output signal from the differential pressure database (step S703). Here, the differential pressure database measures in advance the output signal value of the pressure sensor 81 and the value of the differential pressure ΔP applied to the atmospheric pressure measurement cantilever 84 according to the output signal value for each output signal value. The relationship specified from the measurement result is stored as a database.

  Next, the vertical motion information calculation unit 5 sets an initial value to the first internal pressure Pin (1) having the earliest time among the internal pressure Pin (i) (i = 1 to N, N: natural number of 2 or more). (Step S704). Here, the internal pressure Pin (1) according to the present embodiment is assumed to be atmospheric pressure on the assumption that it is used in the air. Next, the vertical motion information calculation unit 5 adds Pin (i) and the differential pressure ΔP (i) to calculate the external pressure Pout (i) (step S705; differential pressure calculation step).

  Next, the vertical motion information calculation unit 5 reads the flow rate Q (i) of the pressure transmission medium flowing into the cavity 310 from the flow rate database stored in the storage device using the differential pressure ΔP (i) (step S706). . Here, the flow rate database is obtained by measuring the differential pressure ΔP and the flow rate Q corresponding to the magnitude of the differential pressure ΔP in advance for each differential pressure ΔP, and storing the relationship specified from the measurement result as a database. And

  Next, the vertical motion information calculation unit 5 calculates the internal pressure Pin (i + 1) after Δt time from the flow rate Q (i) and the volume V of the cavity (step S707; measurement target pressure calculation step). Here, it is assumed that the fixed time Δt is very small, and the amount of change in the external pressure Pout for each Δt is very small, and the heat transfer and pressure loss are negligibly small. Therefore, the internal pressure Pin increases by the amount that the pressure transmission medium flows into the cavity 310. Therefore, the relationship among the flow rate Q (i), the volume V, the internal pressure Pin (i + 1) and the internal pressure Pin (i) can be expressed by the following equation (2).

Pin (i) × V = Pin (i + 1) × (V + Q (i) × Δt) (2)
For this reason, the in-vehicle data conversion unit 6 can obtain Pin (i + 1) after Δt time by the following equation (3).

Pin (i + 1) = V / (V + Q (i) × Δt) × Pin (i) (3)
Next, the vertical motion information calculation unit 5 stores Pin (i + 1) obtained in step S707 and Pout (i) calculated in step S705 in the storage device that constitutes the vertical motion information calculation unit 5 ( Step S708; flow rate calculation step).

  Next, the vertical motion information calculation unit 5 substitutes i + 1 for i (step S709), determines whether i exceeds N (step S710), and determines that i is equal to or less than N (step S710; N) Repeat the processing of steps S705 to S709 (repetitive processing step). At this time, the vertical motion information calculation unit 5 updates the internal pressure Pin used in step S705 to Pin (i + 1) calculated in step S708 (internal pressure update step).

  When the vertical movement information calculation unit 5 determines that i is greater than N (step S710; Y), the vertical movement information is converted from the obtained N pieces of Pout (step S711). As a relational expression for obtaining an altitude change amount from the atmospheric pressure change amount, an expression (4) obtained by substituting Pout (i + 1) and Pout (i) into P1 and P2 of the expression (1) described in the first embodiment is used.

Δh = 18410.0 × log10 (Pout (i + 1) / Pout (i)) (4)
Here, Δh is the vertical movement amount [m], and Pout is the atmospheric pressure (absolute pressure) [hPa].
Thereby, the vertical motion information calculation part 5 can obtain | require the vertical movement amount at the time of changing from the external pressure Pout (i) to Pout (i + 1).

  As described above, the vertical movement information calculation unit 5 can accumulate N vertical movement amounts in the storage device every Δt time. This information indicates how far the measurement object has moved in the vertical direction during the N × Δt period.

Note that the Δt (predetermined time) may be configured so that the user can appropriately set the user interface unit (not shown) provided in the in-vehicle navigation device 2.
As described above, the vertical motion information calculation unit 5 can measure the time history of the external pressure Pout and the vertical movement amount from the output signal of the pressure sensor 81.

(Modification)
The appropriate speed calculated by the appropriate speed calculation unit 7 according to the above embodiment is not limited to that calculated only according to the road condition, but other factors related to safe driving, such as tire air pressure, brightness around the vehicle ( Alternatively, it may be calculated in consideration of the vehicle light on / off state), the weight of the vehicle, weather conditions (clear weather, rainy weather, fog, etc.), and the like.

  Specifically, the correspondence table stored in the storage area of the appropriate speed calculation unit 7 includes a combination of a road state, one or more other factors related to the above-mentioned safe driving, and a road state and other factors. Correspondence relationship with the appropriate speed determined according to is described. Furthermore, the in-vehicle device 1 is provided with a factor information acquisition unit (not shown) that acquires factor information for specifying other factors. The appropriate speed calculation unit 7 is configured to calculate the appropriate speed from the correspondence table based on the road state estimated by the road state estimation unit 6 and the factor information acquired by the factor information acquisition unit. Here, the factor information acquisition unit, for example, when the other factors are tire air pressure, vehicle weight, and luminance around the vehicle, various air pressure sensors, weight sensors, luminance meters (not shown) provided in the vehicle. ) It has a function to acquire air pressure, weight, and ambient brightness. Further, for example, when the other factor is the weather condition, the factor information acquisition unit is provided with the in-vehicle communication unit 72 in the in-vehicle device as illustrated in the third embodiment. It has a function to acquire more weather conditions.

  In this case, since the appropriate speed calculation unit 7 calculates the appropriate speed that contributes to more accurate safe driving, the in-vehicle device can perform the safety determination with higher accuracy.

DESCRIPTION OF SYMBOLS 1 In-vehicle apparatus 2 Control part 3 Vehicle speed acquisition part (vehicle speed part)
4 Pressure variation sensor 5 Vertical motion information calculation unit 6 Road state estimation unit 7 Appropriate speed calculation unit 8 Safe driving level determination unit 9 Interface unit (notification unit)
DESCRIPTION OF SYMBOLS 10 Cavity 11 Cantilever 12 Gap 13 Piezoresistive element 21 In-vehicle apparatus 22 Position acquisition part 23 Map data 24 Map data storage part 31 Road data 32 Background data 33 Character data 34 Guidance data 41a, 41b, ... In-vehicle apparatus 50 Vehicle safety management System 51 Data management server 52 Vehicle ID data 53 User data 54 Safe driving level data 55 Server communication unit 56 Management server storage unit 61 Administrator device (management terminal)
71 User data 72 In-vehicle communication unit 73 Driver data storage unit 81 Pressure sensor 82 SOI substrate 82a Silicon support layer 82b Oxide layer 82c such as silicon oxide film Silicon active layer 83 Sensor body 83-1 First portion 83-3 of sensor body 2 Second part of sensor body 84 Cantilever 84 for atmospheric pressure measurement Cantilever base end 84b for atmospheric pressure measurement Cantilever distal end 85 for atmospheric pressure measurement Displacement measurement unit 310 Cavity 312 Lid 313 Gap 315 Through hole 320 Piezoresistor 321 Wiring unit 322 Detection Circuit At Intensity threshold f1 First frequency threshold f2 Second frequency threshold p1, p2, p3 Intensity peaks S1 to S7, S11 to S15, S31 to S34 In-vehicle device operation steps S701 to S711 Up and down movement amount calculation operation steps

Claims (10)

An in-vehicle device that is mounted on a vehicle and determines a safe driving level of the vehicle,
A vehicle speed part for detecting a current traveling speed of the vehicle;
An atmospheric pressure fluctuation sensor that continuously measures an atmospheric pressure fluctuation amount during a traveling period to be the object of the determination;
A vertical motion information calculation unit for calculating vertical motion information of the vehicle from the atmospheric pressure fluctuation amount measured by the atmospheric pressure variation sensor;
A road state estimation unit that estimates a state of a road that is traveled by the vehicle during the travel period from the vertical motion information calculated by the vertical motion information calculation unit;
Based on the road state estimated by the road state estimation unit, an appropriate speed calculation unit that calculates an appropriate speed during the traveling period that is the target of the determination on the road;
A safe driving level determination unit that determines the safe driving level based on the traveling speed and the appropriate speed, and outputs determination result information representing a result of the determination;
A notification unit for notifying the determination result information output by the safe driving level determination unit;
A vehicle-mounted device comprising:   The road state estimation unit estimates at least one of presence / absence and inclination angle of a road, presence / absence of a step on a road and the size of the step, presence / absence of a road surface, or a pavement state. The in-vehicle device according to claim 1.   The said safe driving level determination part can set the safe driving level in several steps based on the said appropriate speed, and outputs different determination result information according to the step of safe driving level. Or the vehicle-mounted apparatus of 2. A position specifying unit for specifying the current position of the vehicle;
A speed limit specifying unit that specifies a speed limit of a road on which the vehicle currently travels from the current position specified by the position specifying unit;
With
The in-vehicle device according to any one of claims 1 to 3, wherein the appropriate speed calculation unit calculates the appropriate speed using the speed limit specified by the speed limit specifying unit.   The in-vehicle device according to claim 1, wherein the notification unit notifies the user of the vehicle of the determination result information via at least one of a display screen unit and an audio output unit. . The in-vehicle device is connected via a network with a management terminal that manages a vehicle equipped with the in-vehicle device,
The in-vehicle device according to claim 1, further comprising a communication unit that transmits determination result information output from the safe driving level determination unit to the management terminal via the network.   The in-vehicle device according to claim 6, wherein the notification unit is a communication interface for wireless communication. The atmospheric pressure fluctuation sensor
A cavity having a predetermined volume;
A communication hole through which the pressure transmission medium for transmitting the atmospheric pressure flows into and out of the cavity;
An output unit that outputs an atmospheric pressure fluctuation amount related to a differential pressure between an internal pressure that corresponds to a reference pressure that varies according to atmospheric pressure fluctuation and that represents an internal pressure of the cavity, and the ambient pressure is provided. The in-vehicle device according to any one of claims 1 to 7. The vertical movement information calculation unit
A differential pressure calculation unit for obtaining a differential pressure between the internal pressure and the ambient atmospheric pressure based on the atmospheric pressure fluctuation amount;
A pressure calculating unit that calculates the ambient atmospheric pressure based on the set value of the internal pressure and the differential pressure calculated by the differential pressure calculating unit;
Based on the differential pressure calculated by the differential pressure calculation unit, a flow rate calculation unit that calculates a flow rate per predetermined time of the pressure transmission medium flowing inside and outside the cavity;
Based on the flow rate calculated by the flow rate calculation unit and the volume of the cavity, the internal pressure after a predetermined time is calculated, and the set value of the internal pressure used in the pressure calculation unit is updated with the calculated internal pressure. An internal pressure update unit
The in-vehicle device according to claim 8, wherein The atmospheric pressure variation sensor is provided so as to close an opening surface of the cavity excluding the communication hole, and has a cantilever that bends and deforms according to the differential pressure,
The in-vehicle device according to claim 8 or 9, wherein the output unit outputs a pressure variation amount corresponding to a bending deformation amount of the cantilever.

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