JP2008239051A - On-vehicle alarm device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle alarm device mounted on an automobile, detecting the presence or absence of occurrence of uneven load on each wheel caused by a flat tire or the deviation of the disposition of an occupant and cargo, and informing the occupant in the automobile. <P>SOLUTION: This on-vehicle alarm device has an inclination sensor measuring the inclination of the body of the automobile, a recording means recording the inclination of the body measured by the inclination sensor as an inclination value, an inclination determination means determining whether or not the inclination of the body is changed based on the recorded inclination value, and an informing means informing the user of the automobile of the change in the inclination of the body based on the determined result by the inclination determination means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle alarm device that is mounted on an automobile and detects whether or not there is an imbalance in load on each wheel caused by tire puncture, occupant / cargo arrangement deviation, and the like, and notifies the occupant of the automobile.

  For example, if an excessively heavy load is placed on one side in the width direction of the rear seat or the rear trunk, the center of gravity of the automobile is displaced. Due to the deviation of the center of gravity and the bias of the internal pressure of the tire, the load applied to the specific tire and the drive transmission system that supports the tire becomes extremely high, which may lead to an accident or an early failure. Therefore, in an automobile, it is desirable that deviations in the layout of passengers and cargo are within an allowable range so that there is no extreme deviation in the load applied to each wheel.

Patent Document 1 discloses a configuration for detecting a load bias on a wheel and performing an alarm as described above. In Patent Document 1, a pressure sensor is provided for each wheel, the internal pressure of the tire is detected, and an alarm is output when an abnormality is found.
JP-A-11-263107

  However, in the configuration of the above-mentioned patent document, only the deviation of the load on the wheels due to the deviation of the internal pressure of the tire is detected, and other causes such as those caused by the deviation of the layout of the occupant and the luggage cannot be detected. There was a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an in-vehicle alarm device capable of detecting the presence or absence of occurrence of load bias on each wheel and notifying the passenger of this. To do.

  In order to achieve the above object, an in-vehicle alarm device according to the present invention includes an inclination sensor that measures the inclination of a vehicle body of an automobile, a recording unit that records the inclination of the vehicle body measured by the inclination sensor as an inclination value, and a recording Inclination determining means for determining whether or not a change in the inclination of the vehicle body has occurred based on the determined inclination value, and informing means for notifying the user of the vehicle of the change in the inclination of the vehicle body based on the determination result of the inclination determining means And having.

  With such a configuration, the vehicle occupant can determine that the load on the wheels is uneven due to the tire puncture, the load, and the occupant disposition.

  The on-vehicle alarm device has stop determination means for determining whether or not the vehicle is stopped, and the inclination determination means is the inclination of the vehicle body while the vehicle is stopped based on the determination result of the stop determination means. The notification means may be configured to notify when there is a significant change in the inclination of the vehicle body while the vehicle is stopped based on the determination result of the inclination determination means.

  With such a configuration, the inclination determination means can determine whether or not there has been a change in inclination while the automobile is stopped, so the possibility of a change in inclination due to the movement of the automobile can be excluded, and the load on the wheels can be reduced. Presence or absence of occurrence of bias can be detected more accurately.

  The recording means stores the inclination of the vehicle body immediately after the automobile is stopped as an initial inclination value, and the inclination determination means compares the initial inclination value with the inclination value recorded by the recording means thereafter to It may be configured to determine whether or not there has been a significant change in the inclination of the vehicle body while the vehicle is stopped.

  Further, the in-vehicle alarm device has an engine drive determination unit that determines whether or not the automobile engine is driven, and the recording unit does not record inclination values other than the initial inclination value when the engine is not driven. It is good also as a structure. With such a configuration, since the tilt value is not recorded while the engine is stopped and the vehicle is parked, the problem that the car battery is consumed by the alarm device can be avoided.

  In addition, the tilt sensor has an acceleration sensor that measures the acceleration of three orthogonal components, the tilt sensor measures the tilt of the vehicle body as a vector quantity indicating the direction of gravity applied to the acceleration sensor, and the tilt determination means determines the initial tilt value and Thereafter, a difference from the inclination value recorded by the recording means is calculated, and it is determined whether or not there is a significant change in the inclination of the vehicle body based on the calculation result. Here, the inclination determination means obtains the change direction of the inclination based on the difference between the initial inclination value and the inclination value recorded by the recording means, and the notification means notifies the change direction of the inclination. Then, the user of the automobile can easily determine where the load deviation on the wheels is occurring.

  The recording means may be configured to record the inclination value only when the magnitude of the acceleration vector measured by the inclination sensor is substantially equal to the gravitational acceleration. With such a configuration, when the automobile vibrates due to an external force, the inclination value is not recorded, so that it is possible to more accurately detect the occurrence of a load bias on the wheels.

  The on-vehicle alarm device has an opening detection means for detecting whether at least one of the doors of the automobile is open, and the recording means records an inclination value when at least one of the doors of the automobile is open. It is good also as a structure which does not. With such a configuration, it is possible to exclude the possibility of detecting a change in inclination due to a change in the center of gravity of the vehicle body caused by the opening of the door, and it is possible to more accurately detect the presence or absence of load bias on the wheels.

  Further, the recording means may be configured to calculate the average value of the inclinations measured by the inclination sensor a plurality of times and store the average value as the inclination value so as to measure the inclination more accurately.

  Note that the notification means notifies a vehicle occupant, for example, by displaying a predetermined image on a monitor or outputting a predetermined voice message from a speaker.

  As described above, according to the present invention, it is possible to detect the presence or absence of occurrence of load imbalance on each wheel and notify the passenger of this.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a car navigation device with an alarm function according to the second embodiment. As shown in FIG. 1, the car navigation device 1 of the present embodiment includes a device main body 100, a monitor 210, a speaker 220, a GPS antenna 230, and a remote controller 240.

  First, the vehicle guidance function of the car navigation device 1 will be described. The car navigation device 1 according to the present embodiment detects the coordinates, direction, and speed of a vehicle using GPS (Global Positioning System) or autonomous navigation, and displays an icon indicating a car on a map displayed on the LCD panel 211 of the monitor 210. Is overwritten, and the vehicle position is notified to the vehicle occupant.

  As for the coordinates, azimuth, and speed of the vehicle by GPS, the time signal obtained from the GPS antenna 230 is acquired by the GPS signal receiving unit 133 built in the apparatus main body 100, and the CPU 111 of the apparatus main body 100 acquires the acquired time signal. Obtained by processing. Specifically, time signals from a plurality of GPS satellites whose positions are known are received, and based on this time signal, the CPU 111 calculates an approximate distance from each GPS satellite to the vehicle, and from the plurality of satellites. The coordinates (latitude, longitude, altitude) of the vehicle are obtained based on the distance to the vehicle.

  When the time signal is received while moving, the frequency of the time signal is modulated by the Doppler effect. The GPS receiving unit 133 acquires the degree of this frequency modulation, and based on this, the CPU 111 obtains the relative speed of the vehicle with respect to the GPS satellite. The speed and direction of the host vehicle can be obtained from the degree of modulation of the GPS signal from the time signals from a plurality of GPS satellites. Accordingly, the direction of the host vehicle can be calculated only when the host vehicle is moving.

  As described above, in the car navigation device 1 of the present embodiment, the coordinates, direction, and speed of the host vehicle can be calculated based on the GPS. However, coordinate detection by GPS cannot be used in places such as tunnels where radio waves cannot be received, and the accuracy is greatly reduced in places where multipaths such as urban areas are likely to occur. For this reason, in the car navigation apparatus of this embodiment, the autonomous navigation described below is used in combination.

  In autonomous navigation, the coordinates and direction of the own vehicle can be obtained using the moving speed of the own vehicle, the angular velocity in the yaw direction, and the inclination. In autonomous navigation, the coordinates and direction of the vehicle are acquired as deviations from the initial coordinates and the initial direction of the vehicle, so it is necessary to calculate the initial coordinates and initial direction by using GPS in advance. Yes. The moving speed of the own vehicle is obtained by the CPU 111 acquiring and processing the pulse signal from the rotary encoder attached to the axle of the automobile via the vehicle interface means 134 built in the apparatus main body 100. Further, the angular velocity of the host vehicle is measured by a gyro sensor 131 built in the apparatus main body 100 and transmitted to the CPU 111.

  If it is assumed that the vehicle is moving on a horizontal plane, it is possible to obtain the coordinates and direction of the vehicle based only on the vehicle speed and the angular velocity. However, there is a possibility that the own vehicle travels on a slope and the own vehicle is inclined in the pitch direction or the roll direction. When the host vehicle is inclined in the pitch direction, an error occurs between the speed of the host vehicle on the horizontal plane and the host vehicle speed. Further, when the host vehicle is inclined in the roll direction, an error occurs between the angular velocity measured by the gyro sensor 131 and the angular velocity in the horizontal plane of the host vehicle. Therefore, in order to measure these error components and accurately determine the correct coordinates and direction of the own vehicle, it is necessary to measure the pitch direction and the roll direction inclination of the own vehicle. In the car navigation apparatus 1 of the present embodiment, the inclination of the host vehicle can be measured by the inclination sensor 132 built in the apparatus main body 100.

  The inclination sensor 132 includes a weight and a three-axis acceleration sensor that measures acceleration acting on the weight, and measures the inclination of the vehicle from the acceleration of the weight. That is, when the vehicle is stationary or traveling at a constant speed, the acceleration applied to the weight is only the gravitational acceleration vertically downward. For this reason, the inclination of the own vehicle with respect to the vertical direction can be measured by measuring each component of the gravitational acceleration by the triaxial acceleration sensor. When the host vehicle is accelerating or decelerating, the inclination of the host vehicle is corrected by performing correction based on the orthogonal three-axis components of the host vehicle acceleration calculated by differentiating the speed and angular velocity of the host vehicle. It can be determined accurately.

  The coordinates of the vehicle are obtained by the GPS and autonomous navigation described above. The car navigation device of the present embodiment notifies the vehicle occupant of the position of the vehicle based on the coordinates. The device main body 100 of the car navigation device 1 includes a storage 114 such as a DVD-ROM drive or a hard disk drive. The storage 114 stores map image data in association with coordinates (latitude and longitude). The CPU 111 reads out map image data around the coordinates of the vehicle measured in the above-described procedure from the storage 114, processes it, and transmits it to the display control unit 121 of the apparatus main body 100. The display control unit 121 converts the image data into a video signal of a predetermined format such as an RGB video signal, and sends the video signal to the signal processing circuit 212 of the monitor 210. The signal processing circuit 212 displays a map image on the LCD panel 211 based on the video signal acquired from the display control unit 121.

  The display control unit 121 has an overlay function for superimposing icons, characters, and the like on the map image. The CPU 111 can control the display control unit 121 so that an icon indicating the own vehicle, icons of facilities and landmarks around the own vehicle, an explanatory note, and the like are superimposed on the map image data. Thus, on the map displayed on the LCD panel of the monitor 210, icons such as the own vehicle, surrounding facilities, landmarks, and explanations are superimposed and displayed. As a result, the occupant of the own vehicle can more clearly determine which position the own vehicle is traveling, and can obtain information on facilities around the own vehicle.

  Note that data such as the coordinates of the facilities and landmarks and explanatory texts are stored in the storage 114, and the CPU 111 appropriately reads out data related to the facilities and landmarks around the vehicle. In addition, the car navigation device 1 according to the present embodiment not only visually notifies a specific facility such as a service area by an icon or a description on a map displayed on the monitor 210, but also outputs it from the speaker 220. Notification can be made using a voice message.

  For the above purpose, the device main body 100 of the car navigation device 1 according to the present embodiment includes a speech synthesis circuit 141 and an amplifier 142. The CPU 111 transmits text data such as “3 kilometers to the service area” to the voice synthesis circuit 141. When receiving the text data, the voice synthesis circuit 141 generates a voice signal of the voice that is read out from the text data, and sends the voice signal to the amplifier 142. The amplifier 142 amplifies this audio signal and sends it to the speaker 220. Thus, information on a specific facility is notified to the vehicle occupant as a voice message.

  The operation of the car navigation device 1 is performed via the touch panel 213. The touch panel 213 is a transparent film electrode disposed on the front surface of the LCD panel 211. When the user of the car navigation apparatus 1 touches the touch panel 213, the touch panel 213 touches which position (coordinates) the user touches. And the position is sent to the CPU peripheral circuit 113. By accessing the CPU peripheral circuit 113, the CPU 111 can check whether there is an input on the touch panel 213 and at which position on the touch panel 213 the input has been made.

  In addition, a part of the operation of the car navigation device 1 can be performed using the remote controller 240. A number of buttons are arranged on the remote controller 240, and signals corresponding to the buttons are output by infrared rays. The output monitor 210 is provided with a remote control light receiving unit 214 that receives this infrared signal and transmits it to the CPU peripheral circuit 113 of the apparatus main body 100. The CPU 111 can check which button of the remote controller 240 is pressed by accessing the CPU peripheral circuit 113.

  With the above configuration, the vehicle guidance function of the car navigation device 1 is realized. The CPU 111 reads out a program stored in the ROM 112a of the memory 112, develops it in the RAM 112b, and executes it to execute the various processes described above. The RAM 112b of the memory 112 is also used as a work area at the time of program execution. Each of the storage 114, the gyro sensor 131, the inclination sensor 132, the GPS signal receiving unit 133, the vehicle interface unit 134, and the voice synthesis circuit 141 is connected to the CPU 111 via the CPU peripheral circuit 113.

  The car navigation device 1 according to the present embodiment includes an alarm function that detects an inclination of the host vehicle caused by a deviation or puncture of the position of an occupant or luggage and notifies the occupant. Here, since the automobile tilts even when it is stopped on a slope or a bank, it is necessary to discriminate the inclination caused by the road surface shape and the inclination caused by the deviation or puncture of the position of the passenger or the luggage. In the present embodiment, it is assumed that immediately after the vehicle stops, there is no load or occupant bias in the own vehicle, and the detected inclination of the own vehicle is an inclination due to the road surface shape. Then, compare the inclination immediately after stopping with the inclination after a certain amount of time has elapsed from the time of stopping, and when there is a significant difference between them, the position of the occupant or luggage and the inclination of the vehicle due to puncture Judge that it occurred. The above functions are performed by the CPU 111 executing the routine shown in FIG. The routine shown in FIG. 2 is interrupted when the CPU 111 detects that the vehicle has stopped, that is, the vehicle interface means 134 has detected that the vehicle speed has become 0 based on the speed information obtained from the vehicle. It has become so. However, if it is selected on the setting screen, which will be described later, that the tilt warning is not performed, even if the above condition is satisfied, the routine of FIG. 2 is not executed.

  When this routine starts, step S1 is executed. In step S1, various variables are initialized. Specifically, False is substituted for the variable Al, (0, 0) is substituted for the variable td (x, y), True is substituted for the EngineFlag, and False is substituted for the DriveFlag.

  The variable Al is a flag for determining whether or not the vehicle to be warned is tilted, and means that a slope to be warned is generated when the value is True. The variable td is a vector indicating the direction of inclination. In the present embodiment, the component x of the variable td is a component in the width direction of the vehicle body. If the value is a positive value, it means that there is an inclination that causes the right hand side to be low when viewed from the driver, If it is a value, it means that an inclination is generated such that the left hand side is lowered. Similarly, the component y of the variable td is a component in the longitudinal direction of the vehicle body. If the value is positive, it means that there is an inclination that lowers the front, and if it is negative, the rear is low. It means that a certain inclination has occurred. EngineFlag is a flag indicating whether the engine of the automobile is operating. If EngineFlag is True, it means that the engine is operating and if it is False, it is stopped. DriveFlag is a flag for determining whether or not the vehicle is traveling. If DriveFlag is True, it means that the vehicle is running. Further, if DriveFlag is False, it means that the own vehicle is stopped or moved by means other than self-propelled such as a tow truck.

After the variables are initialized in step S1, step S2 is executed. In step S2, the detection of the initial inclination value _{t 0} is performed. Inclination detection is attempted, the detection result when a successful detection is assigned to a variable t _0. In the present embodiment, the inclination (x, y, z) is a vector of acceleration applied to the vehicle body. The inclination component x is a vehicle body width direction component of acceleration, and the right side is positive and the left side is negative for the driver of the own vehicle. The component y is a vehicle body longitudinal direction component of acceleration, and the front of the host vehicle is positive and the rear is negative. The component z is a vehicle body top / bottom direction component of acceleration, where the foot side is positive and the ceiling side is negative. Therefore, when the host vehicle is stopped, only the gravitational acceleration is detected as the inclination, and the magnitude of the inclination vector is approximately 1G. Further, if the vehicle body is stopped on a horizontal plane and the automobile is not inclined, the x and y components of the inclination are 0 and the z component is 1G. Although details will be described, in step S2, when an automobile transmits during inclination detection, True is assigned to DriveFlag. Next, the process proceeds to step S3.

In step S3, the value of the variable DriveFlag is checked. If DriveFlag is True in step S3, it means that the vehicle has started running before detecting the tilt in step S2. In this case, it is not necessary to detect the initial tilt value t ₀ until the vehicle is stopped again. Therefore, if DriveFlag is True (S3: YES), this routine ends.

Also, if DriveFlag is a False in step S3 (S3: NO), it means that the inclination has been substituted for the variable _{t 0} is performed tilt detection in step S2. Accordingly, in this case (S3: NO), the process proceeds to step S4.

  In step S <b> 4, the CPU 111 acquires engine drive information from the own vehicle via the vehicle interface unit 134. And if the engine of the own vehicle is stopped, it means that it is not necessary to measure the inclination until the engine is driven again. Accordingly, in this case (S4: NO), the process proceeds to step S5.

  In the present embodiment, the car navigation device 1 operates in the power saving mode when the engine is stopped. In the power saving mode, the power supply to the monitor 210, the GPS signal receiving unit 133, the voice synthesis circuit 141, the amplifier 142, the tilt sensor 132, and the gyro sensor 131 is stopped, and the driving frequency of the CPU 111 is lowered to reduce the car navigation. The power consumption per unit time of the entire apparatus 1 is greatly reduced. Since the car navigation device 1 of the present embodiment is supplied with power from the car battery of the own vehicle, the car battery is consumed to a minimum when the car engine is stopped and the car battery is not charged. Can be suppressed. Even in the power saving mode, the vehicle interface means 134 operates and monitors the state of the host vehicle. Then, when the vehicle interface means 134 detects that the engine of the own vehicle has been driven again, it returns from the power saving mode to the normal operation mode (that is, the monitor 210, the GPS signal receiving unit 133, the voice synthesis circuit 141, the amplifier 142, the inclination) The power supply to the sensor 132 and the gyro sensor 131 is resumed and the drive frequency of the CPU 111 is increased). When returning from the power saving mode to the normal operation mode, the process proceeds to step S6.

  On the other hand, if it is confirmed in step S4 that the engine of the host vehicle is being driven (S4: YES), the process proceeds to step S6.

In step S6, an attempt is made to current detection tilt values t _1, when successfully detected inclination and the detection result is substituted for the variable t _1. Next, the process proceeds to step S7.

In step S7, the value of the variable DriveFlag is checked. If DriveFlag is True in step S7, it means that the vehicle has started running before detecting the tilt in step S6. In this case, until the vehicle is stopped again, it is not necessary to perform tilt detection, also, it is necessary to start from the detection of the initial tilt value t ₀ again after stopping. Therefore, if DriveFlag is True (S7: YES), this routine ends.

  On the other hand, if DriveFlag is False in step S7 (S7: NO), the process proceeds to step S8.

In step S8, the value of the variable EngineFlag is checked. If EngineFlag is False in step S8, it means that the engine of the vehicle has stopped before detecting the inclination in step S6. In this case, it is not necessary to detect the inclination until the engine of the vehicle is started again. However, without obtaining an initial inclination value t ₀ again, the inclination determination step to be described later, it is compared with the initial tilt value t ₀ and t ₁ obtained in the previous step S2. For this reason, if EngineFlag is Fasle (S8: NO), it will progress to step S9.

  In step S9, True is substituted for EngineFlag. Next, the process proceeds to step S5 and waits until the engine starts again.

On the other hand, in step S8, when the value of EngineFlag is True means that the gradient value to be performed the slope of the detected variable _{t 1} is substituted at step S6. Therefore, in this case (S8: YES), the process proceeds to step S10.

In the step S10, _{t 0} and _{t 1} from the difference. More specifically, a vector (t ₁ -t ₀ ) is obtained, and a two-dimensional vector obtained by extracting the x and y components of this vector is created. The two-dimensional vector is assigned to the variable t _d. Since both vectors t ₀ and t ₁ are directions of gravity with respect to the vertical direction of the vehicle body at the time of measurement, the vector t _d is a value indicating how much the inclination has changed between steps S2 and S6. That is, the direction indicated by the vector t _d represents a change in direction of the slope. For example, when a change in inclination occurs such that the right front sinks due to a puncture of the right front tire, both the x and y components of the vector t _d are positive values. The magnitude of the vector t _d | t _d | = (x ² + y ² ) ^0.5 indicates the degree of inclination. That is, as the degree of inclination increases, | t _d | also increases. Next, the process proceeds to step S11.

In step S11, it is determined whether or not the magnitude | t _d | of the vector t _d exceeds a predetermined threshold value D. If | t _d | exceeds the threshold value D, the CPU 111 determines that the inclination has changed between step S2 and the immediately preceding step S6. In that case (S11: YES), the process proceeds to step S12.

  In step S12, the variable Al is confirmed. If the variable Al is False, it means that an alarm is not notified at the present time and a new alarm needs to be notified. In such a case (S12: NO), the process proceeds to step S13.

  In step S13, the CPU 111 controls the display control unit 121 (FIG. 1) to display an alarm screen as shown in FIG. 5 on the monitor 210 (FIG. 1). In addition, when outputting a warning by voice is selected according to user settings, the CPU 111 controls the voice synthesis circuit 141 to notify a warning message (the occurrence of a slope and the direction of the slope). Message from the speaker 220. Next, the process proceeds to step S14.

In step S14, the CPU 111 sets the value of the variable Al to True. Then, the process returns to step S4, performing the acquisition again _{t 1.}

On the other hand, if the variable Al is True in step S12, it means that an alarm has already been notified and it is not necessary to newly notify the alarm. However, there is a possibility that the inclination of the own vehicle has changed due to the transshipment of luggage. In such a case (S12: YES), the process proceeds to step S15. In step S15, in accordance with the contents of t _d, it changes the contents of the alarm, if necessary. In other words, when the direction of the inclination changes due to re-loading of the luggage, the content of the alarm displayed on the monitor 210 is updated. In addition, when outputting a warning by voice is selected according to user settings, the CPU 111 controls the voice synthesis circuit 141 to notify a warning message (the occurrence of a slope and the direction of the slope). Message from the speaker 220. Next, the process proceeds to step S16.

  In step S16, it is determined whether or not the alarm function has been canceled by the user of the car navigation apparatus 1. That is, when the user touches the button B1 arranged on the alarm screen in FIG. 5, the user can forcibly stop the alarm display and sound. For example, a warning is output even if the vehicle moves by means other than self-propelled, such as a ferry or a tow truck, and the inclination of the vehicle changes. In such a case, the alarm can be forcibly stopped when the user touches the button B1. The CPU 111 accesses the CPU peripheral circuit 113 to confirm whether or not the user touches the button B1, and if it is touched (S16: YES), the CPU 111 proceeds to step S17. Instead of touching the button B1, the alarm may be stopped by pressing a specific button on the remote controller 240 (FIG. 1).

  In step S17, the display of the alarm screen is deleted (a normal car navigation screen is displayed). If the alarm is set to be output by voice, the voice output is stopped. Next, this routine ends.

  On the other hand, when it is confirmed in step S16 that the user does not touch the button B1 (S16: NO), the process returns to step S4.

In step S11, if | t _d | is equal to or smaller than the threshold value D, the CPU 111 determines that the inclination measured in step S2 of the immediately preceding step S6 is equal and that the inclination to be alarmed has not occurred. . In that case (S11: NO), the process proceeds to step S18.

  In step S18, it is determined whether or not the variable Al is True. If the variable Al is True, it means that a warning is currently being issued, that is, the inclination of the vehicle has been improved by reloading the luggage. In this case (S18: YES), the process proceeds to step S19.

  In step S19, the CPU 111 deletes the alarm screen display. If the alarm is set to be output by voice, the voice output is stopped. Next, the process proceeds to step S20.

  In step S20, False is set to the variable Al. Next, the process returns to step S4.

  In step S18, if the variable Al is False, it means that no alarm is currently issued. In this case (S18: NO), the process returns to step S4.

By executing the above routine, the initial inclination value t ₀ immediately after the host vehicle is stopped is acquired, and the initial inclination value t ₀ is compared with the inclination value t ₁ measured thereafter. When there is a significant difference between them, an alarm for informing the occurrence of the inclination and its direction is output. In addition, since the inclination value t ₁ is repeatedly measured while the engine is being driven, if the inclination of the vehicle changes due to re-loading of luggage when the alarm is output, the inclination value t ₁ depends on the inclination at that time. Thus, the alarm stops, or the direction of the inclination notified by the alarm changes.

In the above routine, when the engine is not driven is not performed measure the tilt value t _1. Therefore, there is no problem that the inclination of the vehicle is measured and the car battery is consumed when the vehicle is parked for a long time.

Next, it will be described acquisition procedure of the initial tilt value t _0. Figure 3 is called at the step S2 in FIG. 2, an acquisition subroutine of the initial tilt value t _0. When this subroutine starts, step S101 is executed first.

  In step S101, 1 is substituted into the variable n. Next, the process proceeds to step S102.

In step S102, the CPU 111 (FIG. 1) determines whether or not the host vehicle has started traveling based on the speed information of the host vehicle output from the vehicle interface unit 134 (FIG. 1). If the vehicle is traveling, there is no need to perform measurement of the initial slope value t _0. In this case (S102: YES), the process proceeds to step S103. If it is confirmed that the vehicle is not traveling (S102: NO), the process proceeds to step S104.

In step S103, CPU 111 is for notifying that a measurement was not made of the initial inclination value _{t 0} to the vehicle has started moving in the main routine, is set to True to a variable DriveFlag. Next, this subroutine is terminated, and the process proceeds to step S3 of the main routine (FIG. 2).

  In step S104, based on the information output from the vehicle interface means 134, the CPU 111 checks whether or not at least one of the doors such as the door, bonnet, and trunk of the vehicle is open. If any of the doors of the own vehicle is open (S104: YES), step S104 is continued. If all the doors are closed (S104: NO), the process proceeds to step S105. That is, step S104 waits until all of the doors are closed when they are open.

In step S105, the CPU 111 acquires the acceleration vector t (x, y, z) measured by the tilt sensor 132 (FIG. 1), and the magnitude of the vector | t | = (x ² + y ² + z ² ) ^{0 .5} is calculated. Then, it is determined whether or not | t | is substantially equal to the gravitational acceleration (for example, within a range of 0.95G to 1.05G). If | t | is substantially equal to the gravitational acceleration (S105: YES), the process proceeds to step S106; otherwise, the process returns to step S102.

In step S106, t is substituted into the variable _t0n . Next, the process proceeds to step S107.

  In step S107, 1 is added to n. Next, the process proceeds to step S108.

In step S108, it is determined whether n is greater than 3, that is, whether n is within a range of 1 to 3. If n is 3 or less (S108: NO), the process proceeds to step S109, and after waiting for 1 second in step S109, the process returns to step S102. If n is larger than 3, that is, if n is 4, the process proceeds to step S110. In other words, in the present embodiment, the inclination values t _{01 to} t ₀₃ are acquired approximately three times every second.

In step S110, CPU 111 calculates a mean value of _t 01 _{~t 03,} Substituting this to _{t 0.} Next, this subroutine is ended, and the process proceeds to step S4 of the main routine (FIG. 2).

As described above, in this subroutine, it measured 3 times the tilt, and the average value and the initial tilt value t _0. This is to prevent a value different from the original inclination from being extracted as an initial inclination value due to a temporary inclination of the vehicle due to vibration or the like. In the present embodiment, the inclination is measured three times. However, it is possible to increase the number of times of measurement and measure the inclination of the host vehicle more accurately.

In addition, when any one of the doors of the own vehicle, the bonnet, the trunk, etc. is open, the inclination is not measured. This is to avoid the problem that the tilt changed by the opened door is measured. Further, in this subroutine, the inclination is stored only when the acceleration of the host vehicle measured by the inclination sensor is approximately gravitational acceleration. That is, the initial inclination value t ₀ can be measured more accurately because the inclination when the host vehicle vibrates due to a force from the outside of the vehicle is not stored as t ₀₁ to t ₀₃ .

Next, it will be explained the procedure of obtaining tilt value t _1. Figure 4 is called at the step S6 in FIG. 2, an acquisition subroutine tilt value t _1. When this subroutine starts, step S201 is executed first.

  In step S201, 1 is substituted into the variable n. Next, the process proceeds to step S202.

In step S202, the CPU 111 (FIG. 1) determines whether or not the host vehicle has started running based on the speed information of the host vehicle output from the vehicle interface unit 134 (FIG. 1). If the vehicle is traveling, it is not necessary to measure the tilt value t _1. In this case (S202: YES), the process proceeds to step S203. If it is confirmed that the vehicle is not traveling (S202: NO), the process proceeds to step S204.

In step S203, CPU 111 is for notifying that the vehicle has not made a measurement of the tilt value _{t 1} for the start to the main routine, is set to True to a variable DriveFlag. Next, this subroutine is terminated, and the process proceeds to step S7 of the main routine (FIG. 2).

In step S204, the CPU 111 determines whether the engine is stopped based on the information output from the vehicle interface means 134. If the engine is stopped, it is not necessary to measure the tilt value t _1. Therefore, in this case (S204: YES), the process proceeds to step S205.

In step S205, CPU 111 in order to notify that the vehicle engine is not carried out measurements of tilt value _{t 1} for stopping the main routine is set to False variable EngineFlag. Next, this subroutine is terminated, and the process proceeds to step S7 of the main routine (FIG. 2).

  In step S204, if the engine of the host vehicle is not stopped (S204: NO), the process proceeds to step S206.

  In step S206, based on the information output from the vehicle interface means 134, the CPU 111 checks whether at least one of the doors such as the door, bonnet, and trunk of the host vehicle is open. If any of the doors of the own vehicle is open (S206: YES), step S206 is continuously executed. If all the doors are closed (S206: NO), the process proceeds to step S207. That is, step S206 waits until all of the doors are closed when they are open.

In step S207, the CPU 111 acquires the acceleration vector t (x, y, z) measured by the tilt sensor 132 (FIG. 1), and the magnitude of the vector | t | = (x ² + y ² + z ² ) ^{0 .5} is calculated. Then, it is determined whether or not | t | is substantially equal to the gravitational acceleration (for example, within a range of 0.95G to 1.05G). If | t | is substantially equal to the gravitational acceleration (S207: YES), the process proceeds to step S208. Otherwise, the process returns to step S202.

In step S208, t is substituted into the variable _t1n . Next, the process proceeds to step S209.

  In step S209, 1 is added to n. Next, the process proceeds to step S210.

In step S210, it is determined whether n is greater than 3, that is, whether n is within a range of 1 to 3. If n is 3 or less (S210: NO), the process proceeds to step S211. After waiting for 1 second in step S211, the process returns to step S202. If n is larger than 3, that is, if n is 4, the process proceeds to step S212. That is, in the present embodiment, the inclination values t _{11 to} t ₁₃ are acquired a total of three times approximately every 1 second.

In step S212, the CPU 111 calculates an average value of t ₁₁ to t ₁₃ and substitutes it for t ₁ . Next, this subroutine is terminated, and the process proceeds to step S7 of the main routine (FIG. 2).

As described above, in this subroutine, it measured 3 times the tilt, and the average value and the initial tilt value t _1. This is to prevent a value different from the original inclination from being extracted as an inclination value due to a temporary inclination of the vehicle due to vibration or the like. In the present embodiment, the inclination is measured three times. However, it is possible to increase the number of times of measurement and measure the inclination of the host vehicle more accurately.

In addition, when any one of the doors of the own vehicle, the bonnet, the trunk, etc. is open, the inclination is not measured. This is to avoid the problem that the tilt changed by the opened door is measured. Further, in this subroutine, the inclination is stored only when the acceleration of the host vehicle measured by the inclination sensor is approximately gravitational acceleration. That is, since the inclination when the host vehicle vibrates due to a force from the outside of the vehicle is not stored as t ₁₁ to t ₁₃ , the inclination value t ₁ can be measured more accurately.

In the present subroutine, unlike subroutines for t ₀ obtained (FIG. 3), when the engine is stopped so that the immediately returns to the main routine (FIG. 2) to interrupt the measurement of the slope value. This is because it is not necessary to measure the inclination value when the engine is stopped. On the other hand, for example, even when the engine is stopped immediately after stopping, the initial inclination value t ₀ is calculated regardless of whether or not the engine is driven so that the change in the inclination of the vehicle can be measured. It is like that.

  Next, the procedure for setting the alarm function of this embodiment will be described below. FIG. 6 is an alarm function setting screen displayed on the monitor 220 (FIG. 1). This screen is displayed by performing a specific operation on the touch panel 213.

  On the alarm function setting screen, buttons B2 and B3 for selecting whether or not to perform an alarm, buttons B4 and B5 for setting whether or not to perform an alarm by sound, and settings for buttons B2 to B5 are determined. A button B7 for canceling the setting contents of the buttons B6 and B2 to B5 is arranged. The user of the car navigation apparatus 1 touches the button B2 when setting to check the tilt change. On the other hand, when it is set not to check the inclination change, the button B3 is touched. Further, when checking the change in inclination, the button B4 is touched when setting to output an alarm by voice, and the button B5 is touched when setting not to perform (that is, the alarm is only displayed on the screen). As shown in FIG. 6, the buttons B2 and B3 and B4 and B5 are paired, and when the user touches one button, the color of the button changes brightly, and the other button The color changes darkly. Thus, the user can clearly determine that the function corresponding to the touched button is selected.

  In this embodiment, when the alarm function is used, an alarm is always displayed on the screen. However, the present invention is not limited to this configuration. For example, only an alarm by voice is used. It is good also as a structure which can select performing.

1 is a block diagram of a car navigation device according to an embodiment of the present invention. 5 is a flowchart of a routine for detecting the inclination of the own vehicle in the embodiment of the present invention. It is an initial inclination value acquisition subroutine corresponding to step S2 of FIG. This is an inclination value acquisition subroutine corresponding to step S6 in FIG. An example of the alarm screen displayed on the monitor is shown. In this embodiment, an example of the setting screen for setting an alarm function is shown.

Explanation of symbols

1 Car navigation device 100 Device body 111 CPU
113 CPU Peripheral Circuit 121 Display Control Unit 132 Inclination Sensor 134 Vehicle Interface Means 141 Speech Synthesizer Circuit 142 Amplifier 210 Monitor 211 LCD Panel 213 Touch Panel 214 Remote Control Light Receiver 220 Speaker 240 Remote Control

Claims (11)

A tilt sensor that measures the tilt of the car body;
Recording means for recording the inclination of the vehicle body measured by the inclination sensor as an inclination value;
Inclination determination means for determining whether a change has occurred in the inclination of the vehicle based on the inclination value recorded by the recording means;
Informing means for informing the occupant of the vehicle of a change in the inclination of the vehicle body based on the determination result of the inclination determining means;
A vehicle-mounted alarm device. The on-vehicle alarm device has stop determination means for determining whether or not the automobile is stopped,
The inclination determination means determines whether or not there has been a significant change in the inclination of the vehicle body while the automobile is stopped based on the determination result of the stop determination means;
The notification means notifies when there is a significant change in the tilt of the vehicle body while the automobile is stopped based on the determination result of the inclination determination means.
The in-vehicle alarm device according to claim 1. The recording means stores the inclination of the vehicle body immediately after the automobile stops as an initial inclination value,
The inclination determination means determines whether or not there has been a significant change in the inclination of the vehicle body while the automobile is stopped by comparing the initial inclination value and the inclination value recorded by the recording means thereafter.
The in-vehicle alarm device according to claim 2. The on-vehicle alarm device has an engine drive determination means for determining whether the engine of the vehicle is driven,
The recording means does not record an inclination value other than the initial inclination value when the engine is not driven.
The in-vehicle alarm device according to claim 3. The tilt sensor has an acceleration sensor that measures acceleration of three orthogonal components,
The tilt sensor measures the tilt of the vehicle body as a vector quantity indicating the direction of gravity applied to the acceleration sensor,
The inclination determination means calculates a difference between the initial inclination value and the inclination value recorded by the recording means, and determines whether or not there is a significant change in the inclination of the vehicle body based on the calculation result; The inclination determination means obtains a change direction of the inclination based on a difference between the initial inclination value and an inclination value recorded by the recording means thereafter,
The notification means notifies the direction of change of the inclination;
The in-vehicle alarm device according to claim 5.   The in-vehicle alarm device according to claim 5 or 6, wherein the recording unit records the inclination value only when the magnitude of the acceleration vector measured by the inclination sensor is substantially equal to the gravitational acceleration. .   The in-vehicle apparatus according to claim 1, wherein the recording unit calculates an average value of inclinations measured by the inclination sensor a plurality of times, and stores the average value as the inclination value. Alarm device. The on-vehicle alarm device has a door detection means for detecting whether at least one of the doors of the automobile is open,
The recording means does not record the tilt value when at least one of the doors of the car is open;
The in-vehicle alarm device according to any one of claims 1 to 8. The in-vehicle alarm device has a monitor that displays an image,
The notification means notifies a change in the inclination of the vehicle body to a passenger of the vehicle by displaying a predetermined image on the monitor.
The in-vehicle alarm device according to any one of claims 1 to 9. The in-vehicle 1 alarm device has a speaker for outputting sound,
The notifying means notifies the occupant of the vehicle of a change in the tilt of the vehicle body by outputting a predetermined voice message to the speaker.
The in-vehicle alarm device according to any one of claims 1 to 9.

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