System and Program

Abstract

To provide a technology capable of acquiring information related to a change of a traveling direction of a vehicle even when it is not possible to acquire a handle steering angle from a steering angle sensor without requiring labor or costs for installing sensors in a plurality of different wheels, and for wire-connecting those sensors, respectively.SOLUTION: A radar detector includes a control part 18 for acquiring information related to rotation of wheels installed in a vehicle from a network for performing control about the vehicle, and for acquiring information related to a change of a traveling direction of the vehicle on the basis of a relation between the acquired information related to the rotation of at least two different wheels.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a system and a program for determining information regarding, for example, a change in the direction of travel of a vehicle. [Background technology]

[0002] In-vehicle electronic devices such as navigation systems and radar detectors determine the vehicle's position based on signals obtained by GPS receivers receiving radio waves from GPS satellites. However, GPS radio waves are often difficult to receive when the vehicle enters a tunnel, underground, in a crowded area with buildings, under an overpass, etc.

[0003] For this reason, when in-vehicle electronic devices cannot receive GPS radio waves, they calculate the vehicle's direction of travel, inclination, distance traveled, etc. based on signals from the vehicle's gyro sensor, acceleration sensor, vehicle speed sensor, etc., and correct the vehicle's position.

[0004] However, it is more accurate to determine the direction of travel of the vehicle from a signal from a steering angle sensor that detects the steering angle of the steering wheel. For this reason, as disclosed in Patent Document 1, if a vehicle is equipped with a steering angle sensor, changes in the direction of travel of the vehicle can be accurately detected by acquiring a signal from the steering angle sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-35566 Summary of the Invention [Problem to be solved by the invention]

[0006] However, not all vehicles are equipped with steering angle sensors, and many vehicles do not have steering angle sensors. Even in vehicles equipped with steering angle sensors, there are cases where the steering angle signal from the steering angle sensor cannot be obtained from the network that controls the vehicle. Furthermore, the data format for the steering angle is not made public, making it difficult to obtain the steering angle.

[0007] Patent Document 1 also describes detecting the direction of travel of a vehicle by detecting the difference in inner or outer wheel rotation speeds of the wheels without using such a steering angle sensor. The same document further describes calculating the amount of displacement in heading by arranging vehicle speed sensors on the left and right and detecting the turning of the vehicle from the difference in output pulses (difference in travel distance) between the sensors.

[0008] However, to achieve this configuration, new vehicle speed sensors must be installed for each of the different wheels and each of these vehicle speed sensors must be connected to the system via wires, which requires time and effort for installation.

[0009] Furthermore, conventional vehicle speed sensors cannot achieve high resolution because they can only output signals of around 2 to 8 pulses per rotation. For this reason, even if a vehicle speed sensor is used, it can only achieve the accuracy required to detect whether the vehicle is turning right or left, and cannot achieve the same level of accuracy as a steering angle sensor.

[0010] Therefore, for example, it cannot detect a change in direction at a fork in the road where the angle is small. It also cannot detect a situation where, for example, a driver exits a highway at an angle to the main road. Furthermore, it cannot detect a change in direction when changing lanes or within the same lane.

[0011] The present invention has been proposed to solve the above problems, and aims to provide a system etc. that can obtain information about changes in the vehicle's direction of travel even when it is not possible to obtain the steering angle from a steering angle sensor, without the effort and cost of installing sensors on multiple different wheels and connecting them with wires. [Means for solving the problem]

[0012] In order to achieve the above object, the system of the present invention comprises: (1) The system is characterized in that information regarding the rotation of the wheels of a vehicle is obtained from a network that controls the vehicle, and information regarding changes in the vehicle's direction of travel is obtained based on the relationship between the information regarding the rotation of at least two different wheels that has been obtained.

[0013] In this way, information regarding changes in the direction of travel can be obtained simply by connecting to a network that controls the vehicle. Therefore, for example, there is no need to install sensors on multiple different wheels and connect these sensors with wires. This is particularly effective when it is not possible to obtain information such as steering angle from the network that controls the vehicle, or when the data format is not publicly available and it is difficult to obtain such information.

[0014] Furthermore, for example, in a configuration in which information regarding a change in the vehicle's direction of travel is obtained using GPS, information regarding a change in the vehicle's direction of travel cannot be obtained in locations where GPS radio waves are blocked and positioning is not possible. However, by obtaining information regarding the rotation of at least two different wheels, information regarding a change in the vehicle's direction of travel can be obtained. For example, a configuration may be provided in which the mileage obtained by GPS is corrected based on information regarding the change in the vehicle's direction of travel. Furthermore, in a vehicle without a steering angle sensor, or even if the steering angle sensor has limited use, or even if the steering angle sensor is broken, information regarding a change in the vehicle's direction of travel can be obtained by obtaining signals regarding the rotation of at least two different wheels.

[0015] The information about wheel rotation may be, for example, the amount of wheel rotation per unit time, such as the number of wheel rotations per unit time or the rotation angle per unit time. Furthermore, the information about wheel rotation may be configured to read information transmitted to a network at predetermined time intervals, particularly for vehicle control. Furthermore, the information about wheel rotation may be information from a sensor installed on each wheel of an existing vehicle and outputting information corresponding to wheel rotation. This configuration allows, for example, a user to easily connect the sensor to a network and use it later.

[0016] The network for controlling the vehicle may be, for example, a network external to the vehicle, but is particularly preferably a network installed in the vehicle. In particular, it is preferably a network through which data used to control the vehicle itself flows. In particular, it is preferably a network to which multiple computers for controlling the vehicle are connected, such as a CAN. The resolution of information regarding wheel rotation in the network through which data used to control the vehicle itself flows is 10 to 100 times higher than the vehicle speed (1 km / h steps), so quantum error is reduced, and even when traveling at low speeds, the error in information regarding changes in the vehicle's traveling direction obtained from information regarding wheel rotation is also extremely small. Therefore, information regarding changes in the traveling direction can be obtained with a level of accuracy comparable to that of, for example, a steering angle sensor.

[0017] Furthermore, for example, it is possible to calculate, for example, vehicle speed and mileage from information about wheel rotation in a network through which data used to control the vehicle itself flows, along with information about changes in the vehicle's direction of travel, and to calculate the gear ratio from separately obtained engine speed and vehicle speed, and it is also possible to reduce errors in vehicle speed, mileage, gear ratio, etc.

[0018] Furthermore, for example, the network provided in the vehicle may be wired or wireless. In particular, for example, if the network is wired, information regarding changes in the vehicle's traveling direction can be obtained simply by connecting a wire to one location on a signal line (e.g., a group of signal lines) of the network. In particular, it is preferable to configure the network signal line to be connected to a detachable connector. For example, it is preferable to configure the network to have a plug that connects to a connector having a network signal line, such as a fault diagnosis connector provided in the vehicle.

[0019] The two different wheels may be, for example, in the case of a four-wheeled vehicle, the left and right front wheels, the left and right rear wheels, the left front wheel and the left rear wheel, the right front wheel and the right rear wheel, the left front wheel and the right rear wheel, or the right front wheel and the left rear wheel.

[0020] "At least two" preferably means two or more. For example, it is preferable to use information corresponding to only two wheels. In this way, for example, the amount of information to be processed is reduced, and processing can be simplified and accelerated. Also, for example, it is possible to use either the information corresponding to two wheels or the information corresponding to the other two wheels, whichever shows a normal value, or to use the average of both pieces of information. In this way, for example, highly accurate detection is possible.

[0021] The information about the rotation of the wheels of the vehicle may be acquired from the network that controls the vehicle at predetermined time intervals. The predetermined time may be, for example, the time required to obtain information about a change in the direction of travel of the vehicle. For example, the information may be instantaneous values ​​of information about the rotation of at least two wheels at approximately the same time.

[0022] The information regarding the change in the traveling direction of the vehicle may be, for example, information indicating the degree of difference between information regarding the rotation of at least two wheels, for example, information based on the difference between values ​​indicated by the information regarding the rotation of the two wheels, or information based on the ratio between values ​​indicated by the information regarding the rotation of the two wheels.

[0023] A change in the direction of travel may be, for example, a right or left turn at a branching point. In this way, for example, the number of directions to be determined is reduced, which simplifies and speeds up processing. A change in the direction of travel may also be, for example, a change in the angle of travel or a change in the steering angle. In this way, for example, more detailed driving conditions can be determined. For example, a change in the direction of travel within the same lane or a change in the direction of travel when changing lanes can be detected. Furthermore, even when GPS positioning is not possible, a change in the direction of travel at a curve in a road at an intersection, underground, or in a tunnel can be detected.

[0024] (2) It is preferable to acquire information regarding the steering angle from a network that controls the vehicle, and detect an abnormal state of the vehicle based on the relationship between the acquired information regarding the steering angle and information regarding the steering angle calculated based on the relationship between the information regarding the rotation of the at least two different wheels.

[0025] While information about the steering wheel angle obtained from the network accurately indicates the steering wheel angle, information about the steering wheel angle calculated based on the relationship between information about the rotation of at least two different wheels may differ from the actual steering wheel angle depending on the state of the vehicle. Therefore, for example, an abnormal state of the vehicle can be detected based on a relationship in which the two pieces of information significantly differ. A method for calculating the steering wheel angle based on the relationship between information about wheel rotation may be as follows: First, a log is created that captures steering wheel angles and information about the rotation of at least two different wheels at approximately the same time at a time interval required to generate information about changes in the vehicle's direction of travel according to the application. A function is then calculated that represents the correspondence between the information about the rotation of at least two different wheels of the vehicle in the log and the steering wheel angle at the same time. The system then uses this function to calculate the steering wheel angle based on the relationship between the information about the rotation of the wheels. For example, the difference or ratio between the instantaneous values ​​of the rotation speeds of two different wheels at the same time is associated with the steering wheel angle at that time and stored as a log, and the correlation between this difference or ratio and the steering angle is stored as a function. The function may be incorporated into the program as a mathematical formula, or may be configured as a program that creates and stores a table for determining the mapping, and performs calculations using this table.

[0026] For example, the data format of the information about wheel rotation and steering angle transmitted through the network may differ depending on the vehicle model. For example, the correspondence between information about wheel rotation and steering angle may be determined in advance for each vehicle model, a function may be calculated, and the function may be stored in the system as a program or data. The system may then be provided with a function for automatically detecting and setting the vehicle model or for the user to manually set the correspondence for the set vehicle model. For example, it may be possible to detect an abnormal condition of the vehicle, such as a flat tire or slippage, based on the relationship between the calculated steering angle and the steering angle obtained from the network.

[0027] An abnormal state of the vehicle may be, for example, a state in which the rotation speed of a specific tire is significantly different from that of other tires, such as a flat tire, abnormal air pressure, or slippage of a specific tire on a snowy, icy, or muddy road.

[0028] (3) It is preferable that the information flowing through the network be read without querying devices connected to the network provided in the vehicle as the network that controls the vehicle.

[0029] In this way, the information flowing through the network is read without collecting information by querying the devices connected to the network, thereby avoiding stress on the devices connected to the network. In particular, stress can be avoided for the computer that outputs information about wheel rotation to the network, as it does not need to respond to queries. Moreover, since there is no increase in network traffic, stress on the overall control of the vehicle can also be avoided.

[0030] (4) It is preferable that the control be such that information regarding the steering angle obtained from a network that controls the vehicle and information regarding the steering angle calculated based on the relationship between information regarding the rotation of the at least two different wheels are displayed on a display screen.

[0031] In this way, a person in the vehicle, including the driver, or an outsider of the vehicle, who is viewing the display screen, can compare the information on the steering wheel angle obtained from the network that controls the vehicle with the information on the steering wheel angle calculated based on the relationship between the information on the rotations of the at least two different wheels. By comparing the two pieces of information on the steering wheel angle in this way, the person in the vehicle or an outsider of the vehicle can determine an abnormal state of the vehicle, for example, from the degree of difference between the two pieces of information.

[0032] The display mode may be, for example, one that allows identification of the difference between information relating to the steering angle acquired from a network that controls the vehicle and information relating to the steering angle calculated based on the relationship between information relating to the rotations of at least two different wheels. For example, the presence of a difference between the two pieces of information may be displayed, the magnitude of the difference may be displayed, or the type of abnormality estimated from the difference may be displayed. In this way, an abnormal state of the vehicle can be easily determined.

[0033] The display screen may be, for example, a display that can be visually recognized. For example, the display screen may be installed inside the vehicle. In this way, for example, a vehicle occupant looking at the display screen can compare the two pieces of information. Alternatively, for example, the display screen may be installed outside the vehicle. In this way, for example, a person outside the vehicle can compare the two pieces of information.

[0034] (5) It is preferable that an abnormal condition of the vehicle is detected based on the relationship between information regarding the steering angle obtained from a network that controls the vehicle and information regarding the steering angle obtained based on the relationship between information regarding the rotation of the at least two different wheels, and that control is performed to display the abnormal condition on a display screen.

[0035] In this way, the abnormal state of the vehicle is displayed on the display screen, so that the passengers in the vehicle, including the driver, or people outside the vehicle can easily recognize the abnormal state of the vehicle without having to go through the trouble of determining the abnormal state themselves. The abnormal state may be indicated by, for example, a flat tire, abnormal air pressure, slippage of a particular tire, or the like, in a manner that allows recognition by characters, figures, colors, or changes in these.

[0036] (6) It is preferable to control the display of information relating to the change in the traveling direction of the vehicle on a display screen.

[0037] In this way, the vehicle occupants, including the driver, or people outside the vehicle who are viewing the display screen can recognize changes in the vehicle's direction of travel. From this change in the vehicle's direction of travel, the vehicle occupants, including the driver, or people outside the vehicle can determine the driving state of the vehicle, which can be useful for safe driving and eco-driving.

[0038] The display screen may be, for example, a display screen installed inside the vehicle. In this way, for example, a passenger in the vehicle can recognize changes in the vehicle's direction of travel. Alternatively, for example, a display screen installed outside the vehicle can be used. In this way, for example, a person outside the vehicle can recognize changes in the vehicle's direction of travel. For example, a taxi company or a transportation company may use a display screen installed in the company to check past or present changes in the driver's vehicle's direction of travel, determine the driver's driving condition, and use this as an indicator to encourage the driver to drive safely and eco-friendly. Alternatively, for example, a driver may use a display screen at home to check past changes in the vehicle's direction of travel, determine the driver's driving condition, and use this as an indicator to encourage the driver to drive safely and eco-friendly.

[0039] The display of information regarding changes in the vehicle's direction of travel may be, for example, a display that allows the driver to determine the vehicle's driving status based on whether or not there has been a change in the direction of travel. For example, the display may be a display that allows the driver to visually grasp instantaneous changes in the vehicle's direction of travel. Furthermore, the display may be a display that allows the driver to visually grasp changes in the vehicle's direction of travel over a predetermined period of time. The predetermined period may be a period that allows the driver to determine, for example, whether the vehicle is repeatedly changing lanes in a short period of time or whether the vehicle is frequently changing its direction of travel within the same lane. The vehicle's driving status determined by the vehicle occupants or a person outside the vehicle may be, for example, a driving status that is consistent with or contrary to safe driving or eco-driving. This may lead to the driver's realization of safe driving or eco-driving. For example, repeated lane changes in a short period of time may be determined by the vehicle occupants or a person outside the vehicle as a driving status that indicates frequent overtaking. For example, frequent changes in the direction of travel within the same lane may be determined by the vehicle occupants or a person outside the vehicle as a driving status that indicates drunk driving or drowsy driving. As a display that can determine the driving condition, it is preferable to display, for example, a graph showing changes in the direction of travel or steering angle over a specified period of time, or numbers showing the frequency of changes in the direction of travel or steering angle over a specified period of time.

[0040] (7) It is preferable that the driving state of the vehicle is determined based on the information relating to the change in the traveling direction of the vehicle, and that the driving state is displayed on the display screen.

[0041] In this way, the driving state of the vehicle is displayed on the display screen, so that passengers in the vehicle including the driver or people outside the vehicle who look at the display screen can easily recognize the driving state of the vehicle without having to go through the trouble of determining the driving state themselves.

[0042] The driving status may be indicated by, for example, danger, safety, drowsiness, drinking, etc., in a manner that can be recognized by letters, figures, colors, or changes in these.

[0043] (8) It is preferable to acquire information relating to the driving operation of the vehicle, and control the display screen to display the acquired information relating to the driving operation of the vehicle together with changes in the direction of travel of the vehicle.

[0044] In this way, information regarding the vehicle's driving operation is displayed along with information regarding changes in the vehicle's direction of travel, so that vehicle occupants, including the driver, or persons outside the vehicle who view the display screen can determine the vehicle's driving condition in more detail based on the relationship between changes in the vehicle's direction of travel and information regarding the driving operation.

[0045] The information about the vehicle's driving operation may be, for example, information indicating the operation of a member or mechanism that the driver needs to operate while driving and the timing of the operation. For example, the information about the vehicle's driving operation may include information such as when the turn signal was turned on, when and how many times the brake was pressed, and when and how many times the accelerator was pressed.

[0046] For example, if the driver does not turn on the turn signal before turning right or left, it may be determined that the driving condition is dangerous. For example, if the driver does not step on the brake before turning right or left, or if the driver steps on the accelerator, it may be determined that the driving condition is dangerous.

[0047] (9) It is preferable to acquire information regarding the driving operation of the vehicle, determine the driving state of the vehicle based on the acquired information regarding the driving operation of the vehicle and changes in the direction of travel of the vehicle, and perform control to display the driving state on a display screen.

[0048] In this way, the display screen displays not only the changes in the vehicle's direction of travel but also the driving status determined by taking into account information about the vehicle's driving operations, so that passengers in the vehicle, including the driver, or people outside the vehicle who view the display screen can easily obtain detailed driving status without having to go through the trouble of determining the driving status themselves.

[0049] (10) It is preferable that a control is performed to output a sound in response to the abnormal state.

[0050] In this way, by outputting a sound, it is possible to reliably notify the vehicle occupants or people outside the vehicle who are not looking at the display screen of an abnormal condition of the vehicle, such as a flat tire, abnormal air pressure, or slippage of a specific tire.

[0051] (11) It is preferable that sound output be controlled in accordance with the operating state.

[0052] In this way, by outputting a sound, it is possible to reliably notify the vehicle's driving status to vehicle occupants or people outside the vehicle who are not looking at the display screen. For example, it is possible to warn vehicle occupants or people outside the vehicle of the dangers of drowsy driving or drunk driving.

[0053] (12) It is preferable that a value indicating the relationship between information regarding the rotation of at least two different wheels at the same time is defined as a single value, and information regarding a change in the vehicle's direction of travel is obtained by using the average value of a predetermined number of consecutive values.

[0054] In this way, even if one of the multiple measurements shows a value that is significantly different from the others, the average value of the multiple measurements is used instead of using that value as is, and the value is smoothed to a value that is closer to the steering angle, thereby enabling more accurate direction detection that is closer to the steering angle sensor.

[0055] The average value of multiple consecutive values ​​can be calculated by, for example, using the average value of multiple values, and then excluding the oldest value and calculating the average value including the next value, and then using the average values ​​calculated sequentially.

[0056] (13) The information relating to the rotation of the wheels of the vehicle may be information based on a signal from a sensor used in the ABS to detect the rotational state of the wheels.

[0057] This method uses the signal from the sensor used in the ABS (anti-lock braking system), which saves the effort and expense of adding a special sensor.In addition, information based on the signal from the sensor used in the ABS has a higher resolution than the transmission's vehicle speed sensor, so direction can be detected more accurately.

[0058] (14) It is preferable that the direction of travel of the vehicle is not detected when the ABS function is activated.

[0059] When the ABS is activated, it is not possible to accurately detect the direction of travel using signals from the sensor, so by not detecting the direction, it is possible to prevent erroneous judgments and incorrect operation due to false detection.

[0060] (15) The system functions of (1) to (14) can be configured as a program for realizing them on a computer. [Effects of the Invention]

[0061] According to the present invention, it is possible to obtain information regarding changes in the vehicle's direction of travel even when it is not possible to obtain steering wheel angle from a steering angle sensor, without the effort and cost of installing sensors on multiple different wheels and connecting them with wires. [Brief explanation of the drawings]

[0062] [Figure 1] 1 is a diagram showing the configuration of a radar detector according to a preferred embodiment of the present invention; [Figure 2] FIG. 1 is a block diagram of a radar detector. [Figure 3] FIG. 10 is an explanatory diagram showing an example of a standby screen. [Figure 4] FIG. 10 is an explanatory diagram showing an example of a warning screen. [Figure 5] FIG. 2 is an explanatory diagram showing an example of a route actually traveled by a vehicle. [Figure 6] 6 is an explanatory diagram showing the steering angle and the wheel difference ratio when traveling along the route in FIG. 5. FIG. [Figure 7] 6 is an explanatory diagram showing the steering wheel angle and the averaged wheel difference ratio when traveling along the route in FIG. 5. FIG. [Figure 8] FIG. 1A is an explanatory diagram showing the vehicle speed when the vehicle is traveling clockwise, and FIG. 1B is an explanatory diagram showing the rotational speed of each wheel. [Figure 9] FIG. 1A is an explanatory diagram showing the vehicle speed when braking while the vehicle is traveling straight on a snowy road, and FIG. 1B is an explanatory diagram showing the rotational speed of each wheel. [Figure 10] FIG. 1(a) is an explanatory diagram showing the engine speed when the accelerator is depressed while the vehicle is traveling straight on a snowy road, FIG. 1(b) is an explanatory diagram showing the vehicle speed, and FIG. 1(c) is an explanatory diagram showing the rotational speed of each wheel. [Figure 11] FIG. 1B is an explanatory diagram showing the vehicle speed when the accelerator pedal is depressed while the vehicle is traveling straight on a snowy road, and FIG. 1C is an explanatory diagram showing the rotational speed of each wheel. DETAILED DESCRIPTION OF THE INVENTION

[0063] [1. Configuration of electronic devices] Figures 1 and 2 show a radar detector 1, which is a preferred embodiment of an electronic device that constitutes the system of the present invention. Figure 1(a) is a perspective view of the front side (the side facing the rear of the vehicle (the driver's side)) of the radar detector 1, and Figure 1(b) is a perspective view of the rear side. Figure 2 is a block diagram of the radar detector 1.

[0064] The radar detector 1 has a thin rectangular case body 2, and is attached and fixed to the dashboard of a vehicle or the like using a bracket 3 attached to the lower rear side of the case body 2.

[0065] A display 5 is provided on the front surface of the case body 2 (the surface facing the rear of the vehicle (driver's side)). The display 5 is a 3.2-inch color TFT LCD display. A touch panel 6 is provided on this display 5 to detect which part of the display 5 has been touched. A volume adjustment button 7 is also provided on the right side of the front surface of the case body 2, and various operation buttons 8 are provided on the left side.

[0066] The right side of the case body 2 is provided with a card insertion slot 9 for inserting a memory card 11 as a removable recording medium, and a memory card reader 10 is built into the card insertion slot 9 inside the case body 2. By inserting the memory card 11 through this card insertion slot 9, the memory card 11 is attached to the memory card reader 10. The memory card reader 10 takes in the data stored in the attached memory card 11. More specifically, the data stored in the memory card 11 includes updated information such as information on new alarm targets (location information such as longitude and latitude, type information, etc.), and this updated information is stored (downloaded) into a database 19 built into the device under the control of the control unit 18, thereby updating the data.

[0067] The database 19 can be realized by a non-volatile memory (for example, an EEPROM) inside the microcomputer of the control unit 18 or externally attached to the microcomputer. Note that map data and information on certain alarm targets are registered in the database 19 at the time of shipment, and data on alarm targets that are added later is updated as described above.

[0068] A GPS receiver 13 is placed inside the upper center of the back side of the case body 2, and a microwave receiver 14 and a radio receiver 15 are placed next to it. The GPS receiver 13 receives GPS signals from GPS satellites and outputs current position (longitude and latitude) information. The microwave receiver 14 receives microwaves of a predetermined frequency emitted from the speed measurement device. The radio receiver 15 receives incoming radio waves of a predetermined frequency. A speaker 16 is also built into the bottom of the case body 2. The speaker port is located on the bottom of the case body 2.

[0069] A DC jack 12 is disposed on the lower side of the side of the case body 2. This DC jack 12 is for connecting a cigarette lighter plug cord (not shown), and is connected to a cigarette lighter socket of a vehicle via the cigarette lighter plug cord to receive power supply.

[0070] In addition to the above-mentioned display 5, a lamp 31, a remote control receiver 32, and an infrared communication device 34 are arranged on the front of the case main body 2 (omitted from FIG. 1). The lamp 31 warns by shining in various colors depending on the type and urgency of the alarm. The remote control receiver 32 communicates data with a remote control (portable device: slave device) 33 via infrared rays and performs various settings for the device. The infrared communication device 34 sends and receives data to and from a communication device with a built-in infrared communication device, such as a mobile phone 35.

[0071] The case body 2 contains a geomagnetic sensor 36 and an acceleration sensor 37. The geomagnetic sensor 36 detects geomagnetism to determine which direction north is relative to the direction of travel. The acceleration sensor 37 detects the acceleration of the vehicle in the forward / backward, left / right, and up / down directions.

[0072] The radar detector 1 of this embodiment also includes a connection cable 22 that connects to an OBD-II (II is the Roman numeral "2," and hereinafter "OBD-II" will be referred to as "OBD2") connector installed in the vehicle. A plug 23 that can be detachably attached to the OBD2 connector of the vehicle is attached to the tip of this connection cable 22. The OBD2 connector is also called a fault diagnosis connector, and is connected to the vehicle's ECU to output various vehicle information.

[0073] The other end of the connection cable 22 is provided with a connector terminal 25 for connection to a socket 24 provided on the side of the case body 2 of the radar detector 1, so that the connection cable 22 can be attached and detached to the radar detector 1. Of course, the connection cable 22 may also be connected directly to the radar detector 1.

[0074] By connecting plug 23 attached to connection cable 22 to the OBD2 connector on the vehicle body, control unit 18 is connected to an in-vehicle network that controls the vehicle and acquires various vehicle information every 0.5 seconds. This vehicle information includes, for example, vehicle speed, engine speed, engine load factor, throttle degree, ignition timing, remaining fuel percentage, intake manifold pressure, intake air flow rate (MAF), injection open time, engine coolant temperature (coolant temperature), temperature of air taken into the engine (intake air temperature), air temperature outside the vehicle (outside air temperature), amount of fuel remaining in the fuel tank (remaining fuel amount), fuel flow rate, instantaneous fuel consumption, accelerator position, turn signal information (operation of left and right turn signals (ON / OFF)), brake position, steering wheel rotation angle information, etc.

[0075] The control unit 18 is a computer equipped with a CPU, ROM, RAM, non-volatile memory, I / O, etc., and is connected to the above-mentioned units to execute predetermined processing based on information input from various input devices (touch panel 6, GPS receiver 13, microwave receiver 14, wireless receiver 15, etc.), and output predetermined warning messages using output devices (display 5, speaker 16, etc.). These basic configurations can be basically the same as conventional ones. For example, for audio output, audio PCM data is stored in EEPROM, which is non-volatile memory, and the control unit 18 reproduces this PCM data and outputs the audio from the speaker 16.

[0076] [2. Basic functions of electronic devices] The functions of the radar detector 1 of this embodiment are stored in the EEPROM of the control unit 18 as programs executed by the computer that is the control unit 18, and are realized by the computer executing these programs. Functions realized by the computer through the programs stored in the control unit 18 include a GPS log function, a standby screen display function, a map display function, a GPS warning function, a radar wave warning function, and a wireless warning function.

[0077] The GPS log function is a function in which the control unit 18 associates the current position detected by the GPS receiver 13 every second with the time of detection and the speed (vehicle speed) and stores the result in a non-volatile memory as a position history. This position history is recorded in, for example, NMEA format.

[0078] The standby screen display function is a function for displaying a predetermined standby screen on the display device 5. Fig. 3(a) shows an example of the standby screen, which shows the speed, latitude, longitude, and altitude of the vehicle detected by the GPS receiver 13.

[0079] As shown in Fig. 3(b), the map display function is a function that accesses the database 19 based on the current position detected by the GPS receiver 13, and reads and displays the map data stored therein. The map display function also has a function that searches for objects to be warned about around the current position based on the position information stored in the database 19, and if an object to be warned about is found in the vicinity, displays information indicating the object to be warned about (such as a target icon 112) superimposed on the corresponding position on the map. Specific display modes are as follows:

[0080] The control unit 18 displays the map so that the vehicle's traveling direction always faces upward in the main display area R1 that occupies almost the entire surface of the display device 5. The control unit 18 displays the map so that the current vehicle position is at the center of the lower side of the main display area R1, and also displays the vehicle icon 111 at that position.

[0081] The control unit 18 displays status information in a status area R2 set above the main display area R1. The status information displayed in the status area R2 includes, from left to right, a current time 121 (in the figure, "15:10"), a GPS radio wave reception level display icon 122 (in the figure, three parallel lines of different lengths indicate the maximum reception level), a no-parking area icon 123 (displayed when the vehicle is in a most important parking area or a priority parking area), a reception sensitivity mode display icon 124 indicating the radar reception sensitivity (in the figure, "SE" indicates the highest sensitivity), a vehicle speed 125 (in the figure, "30 km / h"), and a compass 126. The status area R2 is a transparent area and is positioned using a layer above the main display area R1. This allows the map located below to be seen in places within the status area R2 where no status information is displayed.

[0082] The control unit 18 displays the current scale information (reduction scale) in a scale display area R3 set on the left side of the main display area R1. The scale is set such that the vehicle position is 0 m, and the distance from the vehicle position to the vertical center position of the main area R1 ("500" in the figure) and the distance to the upper position ("1000" in the figure) are displayed in units of "m." When the control unit 18 detects that the main display area R1 has been touched twice consecutively, it displays a map scale change button (not shown) at a predetermined position in the main display area R1 (a position along the scale display area R3) and changes the map scale in response to the touch on the map scale change button. In other words, the control unit 18 changes the scale of the map displayed in the main display area R1 to match the scale of the changed map scale, and also changes the scale information displayed in the scale display area R3.

[0083] When the control unit 18 detects a single touch on the display unit 5 while the standby screen display function is being executed as shown in Fig. 3(a), the control unit 18 displays a menu screen. When the control unit 18 detects that a screen switching button provided on the menu screen has been touched, the control unit 18 switches to the map display function as shown in Fig. 3(b). Similarly, when the control unit 18 detects a single touch on the display unit 5 while the map display function is being executed, the control unit 18 displays a menu screen. When the control unit 18 detects that a screen switching button provided on the menu screen has been touched, the control unit 18 performs processing to switch to the standby screen display function.

[0084] While the standby screen display function or map display function (hereinafter these functions are collectively referred to as the standby functions) is being executed, the control unit 18 executes processing to realize each function such as the GPS warning function, radar wave warning function, and wireless warning function in response to an event that has occurred, and returns to processing the original standby function when the processing of the function has ended. The priority of each function is set in descending order: radar wave warning function, wireless warning function, and GPS warning function.

[0085] The GPS warning function is a process executed at predetermined time intervals (1 second intervals) in response to an event from a timer in the control unit 18. This process calculates the distance between the latitude and longitude of the warning target stored in the database 19 and the latitude and longitude of the current position detected by the GPS receiver 13, and when the calculated distance reaches a predetermined approach distance, displays a GPS warning display 130 (a schematic diagram of the warning target, remaining distance, etc.) as a warning screen on the display 5 as shown in Fig. 4(a), and outputs an approach warning sound from the speaker 16 indicating that the warning target is approaching.

[0086] Such warning targets include locations of drowsy driving accidents, speed measurement devices (radar type, loop coil type, H system, LH system, photocell type, mobile type, etc.), speed limit change points, enforcement areas, checkpoint areas, no parking monitoring areas, N system, traffic monitoring systems, intersection monitoring points, red light ignorance prevention systems, police stations, accident-prone areas, areas with high rates of vehicle theft, sharp / continuous curves (expressways), branching / merging points (expressways), ETC lane advance guidance (expressways), service areas (expressways), parking areas (expressways), highway oases (expressways), smart interchanges (expressways), gas stations in PAs / SAs (expressways), tunnels (expressways), highway radio receiving areas (expressways), prefectural border announcements, roadside stations, view point parking, etc. Information on the type of these targets, latitude and longitude information indicating their positions, schematic diagram or photograph data to be displayed on the display 5, and audio data are associated with each other and stored in the database 19.

[0087] FIG. 4(a) shows an example of a display of the radar wave warning function. This radar wave warning function is an alarm function that displays a GPS warning display 131 as an alarm screen on the display 5 and outputs an alarm sound from the speaker 16 when the microwave receiver 14 detects a signal corresponding to microwaves in a frequency band emitted by a speed measurement device (such as a mobile radar (hereinafter simply referred to as "radar")). For example, when the microwave receiver 14 detects microwaves in the frequency band of microwaves emitted by a radar, as shown in FIG. 4(b), a schematic diagram or photo of a radar stored in the database 19 is displayed as an alarm screen on the display 5, and audio data stored in the database 19 is read and output from the speaker 16 saying, "This is radar. Watch your speed." The distance to be displayed may be, for example, a distance estimated from the electric field strength.

[0088] The radio alarm function is a function that issues an alarm when radio waves emitted by an emergency vehicle or the like are received by radio receiver 15 to prevent interference with the vehicle's travel. The radio alarm function scans frequencies for police radios, car location radios, digital radios, special small radios, police station activity radios, police telephones, police activity radios, tow truck radios, helicopter radios, fire helicopter radios, fire department radios, emergency radios, highway radios, and security radios. When a radio signal is received at a scanned frequency, a schematic diagram indicating that a radio signal corresponding to the frequency stored for that radio type in database 19 has been received is displayed on display 5 as an alarm screen. Audio data stored for each radio type in database 19 is read, and an audio alarm indicating the radio type is output from speaker 16. For example, when a police radio signal is received, an audio message such as "This is a police radio signal. Watch your speed." is output.

[0089] [3. Vehicle driving state detection function] The following describes the vehicle running state detection function realized by the control unit 18 in addition to the above basic functions. The vehicle running state detection function includes a function to acquire information about wheel rotation, a function to detect changes in vehicle direction, a function to detect abnormal conditions in the vehicle, etc.

[0090] [Function to obtain information about wheel rotation] The function for obtaining information about wheel rotation is a function for obtaining information about wheel rotation from the in-vehicle network that controls the vehicle. Details of this function are as follows:

[0091] First, as described above, by connecting the plug 23 of the connection cable 22 connected to the radar detector 1 to the OBD2 connector on the vehicle body side, the control unit 18 is connected to the in-vehicle network that controls the vehicle.

[0092] This in-vehicle network is a CAN (Controller Area Network) that connects computers (ECUs) located in various parts of the vehicle for vehicle control and through which data used to control the vehicle itself flows. In this way, it is sufficient to simply connect the control unit 18 to the CAN that controls the vehicle. There is no need to install new sensors on multiple different wheels and connect these sensors with wires.

[0093] The control unit 18 does not query the ECU by transmitting a remote frame or the like. The control unit 18 acquires information about the rotation of each wheel at 10 ms intervals, which is transmitted to the CAN and used to control the vehicle itself. This information is used by the ABS (anti-lock braking system) and is information about the rotation speed of each wheel output from sensors that detect the rotational status of each of the four wheels. The resolution of the information about the rotation speed of the wheels from the sensors used by the ABS is 10 to 100 times higher than the vehicle speed (in 1 km / h steps).

[0094] In the case of a vehicle equipped with a steering angle sensor, steering wheel rotation angle information (steering wheel angle) can be obtained from the OBD2 as described above. However, not all vehicles are equipped with a steering angle sensor. In this embodiment, whether the vehicle is equipped with a steering angle sensor or not, it is possible to detect changes in vehicle direction and abnormal conditions based on information output from the sensor used in the ABS.

[0095] [Vehicle direction change detection function] The vehicle direction change detection function is a function that the control unit 18 detects a change in the direction of the vehicle as information about a change in the vehicle's traveling direction based on the relationship between information about the rotation of two different wheels acquired by the information acquisition function. Details of this function are as follows.

[0096] First, the database 19 stores information about the rotational speed of each wheel that is acquired by the control unit 18 and transmitted over the CAN every 10 ms. Then, the control unit 18 calculates the ratio between the instantaneous values ​​of the information about the rotational speeds of the two wheels at the same time, and subtracts 1 from this ratio. In this embodiment, the value calculated in this way is called the wheel difference ratio.

[0097] The two wheels that can be used to calculate the wheel difference ratio are as follows: Left and right front wheels Left and right rear wheels Left front and left rear wheels Right front and right rear wheels Left front wheel and right rear wheel Right front wheel and left rear wheel

[0098] (Example of wheel difference ratio measurement during actual driving) An example will be described in which the wheel difference ratio between the left front wheel and the right front wheel was calculated by driving on an actual road. The route traveled was a gourd-shaped road connected to a straight road, as shown in Figure 5, and the vehicle entered the gourd-shaped road from the straight road, went around in a clockwise direction, and then exited onto the straight road again.

[0099] FIG. 6 is a graph in which the vertical axis represents the wheel difference ratio (%) calculated by the control unit 18 as described above while traveling along the route in FIG. 5, and the horizontal axis represents time (seconds). The total measurement time, measured on the horizontal axis, is 94 seconds. The graph in FIG. 6 also shows, on the right vertical axis, steering wheel rotation angle information (steering wheel angle) in degrees (°) that the control unit 18 obtained from the OBD 2 simultaneously with the measurement. The graph in FIG. 6 can be displayed on the display 5 during or after the measurement, based on the data calculated by the control unit 18 and stored in the database 19 as described above.

[0100] The measurement results will be explained in detail below with reference to Figures 5 and 6. The curves (1) to (9) on the route in Figure 5 correspond to (1) to (9) in Figure 6. The arrows in Figure 5 indicate the direction of travel of the vehicle. First, the vehicle travels straight along the straight route on the left side of Figure 5 and enters a gourd-shaped route. At this point, the vehicle turns left at the T-junction (1). Then, the steering angle reaches approximately +290.0° and the wheel difference ratio reaches approximately +29.00.

[0101] Next, the vehicle passes through a gentle left-hand curve (2). At this time, the steering angle reaches approximately +20.0° and the wheel differential ratio reaches approximately +2.00. Then, the vehicle passes through a right-hand curve (3). At this time, the steering angle reaches approximately -40.0° and the wheel differential ratio reaches approximately -4.00.

[0102] The vehicle then passes through a gentle right-hand curve (4). At this time, the steering angle reaches approximately -20.0° and the wheel differential ratio reaches approximately -2.00. The vehicle then passes through a right-hand curve (5). At this time, the steering angle reaches approximately -30.0° and the wheel differential ratio reaches approximately -3.00.

[0103] Next, the vehicle passes through a left-hand curve (6). At this time, the steering angle reaches approximately +50.0° and the wheel differential ratio reaches approximately +5.00. Then, the vehicle passes through a right-hand curve (7). At this time, the steering angle reaches approximately -60.0° and the wheel differential ratio reaches approximately -6.00. After that, the route becomes almost straight, so both the steering angle and wheel differential ratio remain near 0.

[0104] The vehicle then passes through a right-hand curve at (8). At this time, the steering angle reaches approximately -40.0° and the wheel differential ratio reaches approximately -4.00. The vehicle then turns left at a T-junction at (9) and exits onto a straight road. At this time, the steering angle reaches approximately +300.0° and the wheel differential ratio reaches approximately +30.00.

[0105] As a result of the above, it can be seen that the wheel difference ratio is almost identical to the steering angle. The control unit 18 can detect that the steering wheel is turned left if the wheel difference ratio is positive, and that the steering wheel is turned right if the wheel difference ratio is negative. In other words, it is possible to determine not only right and left turns but also the traveling direction of the vehicle with an accuracy equivalent to the steering angle. Furthermore, it is possible to detect whether a right or left turn has been made at an intersection, T-junction, L-junction, etc., based on a threshold value set in the database 19. For example, it is possible to detect a left turn if the wheel difference ratio is a threshold value of +10.00 or more, and a right turn if the wheel difference ratio is a threshold value of -10.00 or less.

[0106] The control unit 18 may also calculate the wheel difference ratio as follows: An instantaneous value of information relating to the rotation speed of the left front wheel is considered to be one value, and an average value of a predetermined number of consecutive values ​​is calculated. Also, an instantaneous value of information relating to the rotation speed of the right front wheel at the same time is considered to be one value, and an average value of a predetermined number of consecutive values ​​is calculated. A ratio is calculated between the average value of the left front wheel and the average value of the right front wheel calculated in this way, and 1 is subtracted from this ratio. After calculating a value using the average value of the multiple values, the wheel difference ratio is calculated as described above using the successively calculated average values.

[0107] FIG. 7 shows a graph with the wheel difference ratio calculated in this way on the vertical axis and time on the horizontal axis. This graph also shows the steering angle that the control unit 18 simultaneously acquired from the OBD2. As is clear from this graph, the wheel difference ratio calculated from the average value of multiple instantaneous values ​​of information related to the wheel rotation speeds also nearly coincides with the steering angle. Furthermore, by using the average value, even if there is a value among the multiple values ​​that is extremely different from the others, it is smoothed to a value that is closer to the steering angle.

[0108] (Example of measuring the rotational speed of each wheel during actual driving) To demonstrate why a direction change can be detected from the wheel difference ratio as described above, Fig. 8 shows data obtained by the control unit 18 measuring and comparing the rotational speeds of each wheel when the vehicle simply drives straight through a parking lot, turns right, and then goes straight again. The graph in Fig. 8 can also be displayed on the display unit 5 during or after the measurement, based on the data acquired by the control unit 18 and stored in the database 19 as described above.

[0109] FIG. 8(a) is a graph showing vehicle speed. This vehicle speed may be a value obtained from OBD2 or a value based on GPS. One hundredth of the value on the vertical axis indicates the speed in km / h. The value on the horizontal axis indicates seconds. The measurement time is 30.9 seconds.

[0110] Figure 8(b) is a graph showing the rotational speed of each wheel measured simultaneously with the vehicle speed. The vertical axis shows the instantaneous value of the information related to the rotational speed of each wheel. The acquisition timing is approximately every 0.01 seconds. The numbers on the horizontal axis show seconds.

[0111] As shown in Figure 8(a), the vehicle speed increases from 2.3 to 4.5 seconds after the start of measurement. At this time, the vehicle is traveling straight, so the rotational speeds of each wheel are almost the same, as shown in Figure 8(b). Then, from 4.5 to 23.0 seconds, the vehicle is traveling clockwise, so there is a difference in the rotational speed of each wheel. Furthermore, from around 24.3 seconds, as the vehicle speed decreases, the vehicle returns to traveling straight, and the rotational speeds of each wheel once again become equal.

[0112] As shown in Figure 8(b), when the vehicle is traveling clockwise, the inner right front and right rear wheels rotate slowly, while the outer left front and left rear wheels rotate quickly. The left front wheel rotates fastest and the right rear wheel rotates slowest.

[0113] Therefore, in the case of a simple right turn, the wheel difference ratio between the diagonally opposite wheels, the left front wheel and the right rear wheel, will be the largest. Conversely, it can be easily inferred that in the case of a left turn, the wheel difference ratio between the right front wheel and the left rear wheel will be large. The wheel difference ratios with the next largest are between the left front wheel and the right front wheel, or between the left rear wheel and the right rear wheel. The wheel difference ratios between the left front wheel and the left rear wheel, or between the right front wheel and the right rear wheel, are smaller than the others, but the differences are clearly evident. For example, in Figure 8(b), the numerical values ​​showing the rotational speed of each wheel around 10 seconds are 623 for the left front wheel, 576 for the left rear wheel, 507 for the right front wheel, and 457 for the right rear wheel.

[0114] As described above, it is clear that the rotational speeds of the wheels differ when the vehicle changes direction. Therefore, the control unit 18 can detect a change in direction by comparing information about the rotational speeds of any two wheels.

[0115] [Vehicle abnormality detection function] The vehicle abnormality detection function is a function in which the control unit 18 detects slippage of a specific wheel as an abnormal condition of the vehicle based on the relationship between information about the rotation of at least two different wheels. Note that the control unit 18 can also display the graphs shown below on the display unit 5 based on the data stored in the database 19 during or after measurement.

[0116] (Sudden braking on snowy roads) Figure 9 is a graph showing the slip state when a front-wheel drive vehicle suddenly brakes while traveling straight on a snowy road. The vertical axis of Figure 9(a) represents vehicle speed, and the horizontal axis represents time. Vehicle speed can be a value obtained from OBD2 or a value based on GPS. One-hundredth of the value on the vertical axis represents speed (km / h). The value on the horizontal axis represents seconds. The total measurement time on the horizontal axis is 95 seconds. The vertical axis of Figure 9(b) represents the instantaneous value of information about the rotational speed of each wheel measured simultaneously with the vehicle speed. The acquisition timing is approximately 0.01 second intervals. The value on the horizontal axis represents seconds.

[0117] First, as shown in Figure 9(a), stable driving continues from the start of measurement until around 25 seconds, and the rotational speeds of each wheel are almost the same. Then, around 25 seconds, the brakes are applied hard. Without the ABS, the wheels would be locked and the rotational speed of each wheel would be almost zero. However, because the ABS is active, the rotational speed of each wheel only drops slightly. The ABS controls each wheel appropriately using control values. However, as a result, the actual rotational speed of each wheel differs. This is due to differences in the steering angle, road surface conditions, and the contact state of each wheel with these conditions, among other factors.

[0118] For this reason, as shown in Fig. 9(b), the left front wheel has the slowest rotation speed and is slipping the most. Here, when the control unit 18 determines that there is slip based on a threshold value previously set in the database 19, it warns the user by displaying a speech bubble saying "Left front wheel is slipping" on the display 5, superimposed on the graph, as shown in Fig. 9(b). The warning display area is an area that avoids the lines that indicate the data.

[0119] The threshold value may be, for example, when the rotation speed of a specific wheel drops by more than one-third of the rotation speed of any of the other wheels. Note that the threshold value for issuing a warning may be determined based on experiments, etc., and it is not necessary to issue a warning every time a difference in the rotation speed of the wheels occurs.

[0120] After this, the brakes continue to be applied from around 25 to 47 seconds. As a result, the vehicle gradually decelerates, as shown in FIG. 9(a). In particular, around 33 seconds, the right front wheel exhibits the slowest rotational speed and is slipping significantly, as shown in FIG. 9(b). At this point, the control unit 18 warns the user by displaying a speech bubble on the display 5 saying "Right front wheel is slipping" over the graph.

[0121] Then, from around 47 to 56 seconds, the brakes are not applied. As a result, the vehicle speed decreases very gradually, as shown in Figure 9(a). At this time, the rotational speeds of each wheel are stable and nearly identical, as shown in Figure 9(b). Then, around 56 seconds, the brakes are applied again, which causes the vehicle speed to suddenly decrease, as shown in Figure 9(a).

[0122] At this time, as shown in FIG. 9(b), the right front wheel has the slowest rotation speed and is slipping the most. Here, the control unit 18 warns by displaying a speech bubble saying "Right front wheel is slipping" on the display 5, superimposed on the graph. Next, the left front wheel also slows down its rotation speed and is slipping. Here, the control unit 18 warns by displaying a speech bubble saying "Left front wheel is slipping" on the display 5, superimposed on the graph.

[0123] From around 63 seconds, the rotational speed of each wheel stabilizes and becomes almost the same. Stable driving continues thereafter, and from around 70 seconds, the speed gradually increases by stepping on the accelerator without braking.

[0124] (Snowy Road Acceleration 1) Figure 10 is a graph showing the slip state when the accelerator is depressed while driving straight on a snowy road in a front-wheel drive vehicle. In Figure 10(a), the vertical axis from 0 to 6000 rpm represents engine speed, and the horizontal axis represents time (seconds). In Figure 10(b), the vertical axis from 0 to 8000 represents vehicle speed (1 / 100 is speed in km / h), and the horizontal axis represents time (seconds). In Figure 10(c), the vertical axis represents the value indicating the rotational speed of each wheel, and the horizontal axis represents time (seconds), with the total measurement time being 155 seconds.

[0125] As shown in Figure 10(a), when the accelerator is depressed around 3.7 seconds after the start of measurement, the engine speed rises sharply. At around 11.2 seconds, the accelerator is still depressed, but the rate of increase in engine speed slows slightly as the vehicle is going uphill. Following the increase in engine speed around 3.7 seconds, vehicle speed increases around 12 seconds, as shown in Figure 10(b). Note that if the vehicle speed drops, the engine speed will also drop after a delay.

[0126] Here, around 12 seconds after the vehicle speed has increased, the rotational speed of the left front wheel increases and the wheel begins to slip, as shown in Figure 10(c), and about four seconds later, the rotational speed of the right front wheel increases and the wheel begins to slip. When the control unit 18 determines that a wheel is slipping based on a threshold value previously set in the database 19, it warns the user by displaying speech bubbles saying "Left front wheel is slipping" and "Right front wheel is slipping" on the display 5, superimposed on the graph, as shown in Figure 10(c).

[0127] The threshold value may be when the rotational speed of a specific wheel becomes half or more of the rotational speed of any of the other wheels. The threshold value for braking is the same as that for sudden braking on snowy roads described above. The threshold value for the warning can be determined based on experiments, etc., and it is not necessary to issue a warning every time a difference in wheel rotational speed occurs.

[0128] After that, from around 23 to 76 seconds, as shown in Figure 10(a), the engine speed fluctuates, but this is simply due to the accelerator being pressed depending on the terrain. Therefore, as shown in Figure 10(b), the vehicle speed increases gradually until around 82 seconds. Also, as shown in Figure 10(c), the rotational speed of each wheel is consistent.

[0129] Furthermore, as shown in Figure 10(a), the accelerator is suddenly depressed around 76 seconds, and then lightly depressed until around 110 seconds. Then, as shown in Figure 10(b), the vehicle speed suddenly increases around 82 seconds, then drops briefly, and then increases again. At this time, as shown in Figure 10(c), the speeds of the right and left front wheels suddenly increase and both slip, and while the right front wheel returns to normal, the left front wheel continues to slip, and the right front wheel begins to slip again, and at around 117 seconds, both wheels return to normal.

[0130] At this time, the control unit 18 warns of slippage by displaying speech bubbles saying "Left front wheel is slipping" and "Right front wheel is slipping" on the display 5, superimposed on the graph, as shown in Fig. 10(c). The reason why only the front wheels slip on the left and right is because they are the drive wheels. Also, the reason why the behavior of the left and right wheels differs is because there is a difference in slipperiness, such as when the right side is a road and the left side is icy.

[0131] Next, as shown in Figure 10(a), when the accelerator is depressed at around 126 seconds, the engine speed rises sharply. Later, at around 131 seconds, as shown in Figure 10(b), the vehicle speed rises slightly, and the left front wheel slips slightly, as shown in Figure 10(c). However, the control unit 18 does not issue a warning because it considers this level of increase in speed to be a slight slip that does not reach the threshold.

[0132] Finally, as shown in Figure 10(a), when the brake is applied at around 151 seconds, the vehicle speed decreases slightly as shown in Figure 10(b), and the left front wheel slips slightly as shown in Figure 10(c). In this way, a slip caused by braking appears as a decrease in rotational speed, in contrast to a slip caused by the accelerator. Note that the control unit 18 does not issue a warning because it considers this level of slip to be a slight slip that does not reach the threshold.

[0133] (Snowy Road Accel 2) Like Fig. 10, Fig. 11 is a graph showing the slip state when the accelerator is depressed while driving straight on a snowy road in a front-wheel drive vehicle. However, the measurement time on the horizontal axis is longer than that in Fig. 10, at 321 seconds. In Fig. 10(a), the vertical axis from 0 to 7000 indicates vehicle speed (1 / 100 is speed in km / h), and the horizontal axis indicates time (seconds). In Fig. 10(b), the vertical axis indicates the value indicating the rotational speed of each wheel, and the horizontal axis indicates time (seconds).

[0134] As is clear from this graph, when the accelerator is pressed on a snowy road and the vehicle speed increases suddenly, the rotational speed of the right and left front wheels increases, causing a slip, just like in Snowy Road Slip 1.

[0135] [4. Effects of the embodiment] According to the present embodiment described above, the following effects can be obtained. (A) By simply connecting to a network that controls the vehicle, the control unit 18 can obtain information about changes in the direction of travel. Therefore, for example, there is no need to install sensors on multiple different wheels and connect these sensors with wires. This is particularly effective when it is not possible to obtain information such as steering angle from the network that controls the vehicle, or when the data format is not publicly available and it is difficult to obtain such information.

[0136] (B) In a configuration in which information regarding a change in the vehicle's traveling direction is obtained by GPS, information regarding a change in the vehicle's traveling direction cannot be obtained in places where GPS radio waves are blocked and positioning is not possible, but the control unit 18 can obtain information regarding the rotation of at least two different wheels to obtain information regarding the change in the vehicle's traveling direction. Note that the control unit 18 may be configured to correct the travel distance obtained by GPS based on the information regarding the change in the vehicle's traveling direction.

[0137] In the case of a vehicle without a steering angle sensor, even if the steering angle sensor is present but its use is limited, or even if the steering angle sensor is broken, the control unit 18 can obtain information regarding changes in the vehicle's direction of travel by obtaining signals related to the rotation of at least two different wheels.

[0138] (C) The resolution of information about wheel rotation in the network through which data used to control the vehicle itself flows is 10 to 100 times higher than the vehicle speed (1 km / h steps). This reduces quantum error, and even when traveling at low speeds, the error in information about changes in the vehicle's direction of travel obtained by the control unit 18 from information about wheel rotation is extremely small. Therefore, the control unit 18 can obtain information about changes in the direction of travel with a level of accuracy comparable to that of a steering angle sensor.

[0139] The control unit 18 can calculate the vehicle speed and mileage from information about wheel rotations in a network through which data used to control the vehicle itself flows, along with information about changes in the vehicle's direction of travel, and can also calculate the gear ratio from separately acquired engine speed and vehicle speed. In this way, errors in the calculated vehicle speed, mileage, gear ratio, etc. can be reduced.

[0140] (D) The network provided in the vehicle is a wired network. Therefore, the control unit 18 can obtain information about changes in the vehicle's traveling direction simply by connecting to one of the network's signal lines (e.g., a group of signal lines) by wire. In particular, the control unit 18 is configured to connect to a detachable connector on the network's signal lines, making the connection easy.

[0141] (E) By using information corresponding to only two wheels, the control unit 18 reduces the amount of information to be processed, enabling simpler and faster processing. Furthermore, the control unit 18 obtains and uses instantaneous values ​​of information relating to the rotation of at least two wheels at approximately the same time from the network every 10 ms. Therefore, this information is sufficient for the control unit 18 to determine information relating to changes in the vehicle's traveling direction.

[0142] (F) The control unit 18 does not collect information by querying devices connected to the network, but reads information flowing through the network, thereby avoiding stress on devices connected to the network. In particular, stress can be avoided for the computer that outputs information about wheel rotation to the network, since it does not need to respond to queries. Moreover, since there is no increase in network traffic, stress on the overall control of the vehicle can also be avoided.

[0143] (G) The control unit 18 displays on the display screen of the display device 5 the information about the steering wheel angle acquired from the network and the information about the steering wheel angle calculated based on the relationship between the information about the rotations of two different wheels. This allows the vehicle occupants, including the driver, to compare the information about the steering wheel angle acquired from the network that controls the vehicle with the information about the steering wheel angle calculated based on the relationship between the information about the rotations of two different wheels. By comparing the two pieces of information about the steering wheel angle in this way, the vehicle occupants can determine whether the vehicle is changing direction or is in an abnormal state based on the degree of difference between the two pieces of information.

[0144] Furthermore, since the abnormal state of the vehicle is displayed on the display screen of the display device 5, vehicle occupants, including the driver, can easily recognize the abnormal state of the vehicle without the hassle of determining the abnormal state themselves. For example, the control unit 18 can make the vehicle occupants aware of the occurrence of a slip by displaying a warning in a speech bubble superimposed on a graph. The control unit 18 can prevent the data from becoming difficult to see by setting the warning display area to an area that avoids the lines that indicate the data. Furthermore, the control unit 18 can prevent the warning from being displayed too frequently, which makes it difficult to recognize the danger, by not issuing a warning for minor slips.

[0145] Furthermore, vehicle occupants, including the driver, who look at the display screen can recognize changes in the vehicle's direction of travel and determine the vehicle's driving status based on these changes in the vehicle's direction of travel, which can be useful for safe and eco-friendly driving.

[0146] (H) The control unit 18 uses signals from sensors used in the ABS (antilock braking system), which saves the effort and expense of adding special sensors. In addition, information based on signals from sensors used in the ABS has higher resolution than a vehicle speed sensor in the transmission, allowing for accurate direction detection.

[0147] Furthermore, even if the information about wheel rotation acquired by the control unit 18 from the network contains a value that is significantly different from the others among multiple values, the value is not used as is, but the average value of the multiple values ​​is used, thereby leveling it to a value that is closer to the steering angle. Therefore, direction detection with higher accuracy is possible, closer to that of a steering angle sensor.

[0148] 5. Other Embodiments The present invention is not limited to the above-described embodiments. (a) "Information about wheel rotation" may be the amount of wheel rotation per unit time, the number of wheel rotations per unit time, or the angle of wheel rotation per unit time. Such information also indicates different values ​​for each wheel when the vehicle changes direction or an abnormal driving state occurs, so that the control unit 18 can detect the direction change or abnormal state, as in the above embodiment.

[0149] (b) The "network for controlling the vehicle" may be a network outside the vehicle. The network may be wired or wireless. For example, by obtaining information about wheel rotation from an external network that collects data while the vehicle is running, a person outside the vehicle can compare information about the steering angle obtained from the network for controlling the vehicle with information about the steering angle calculated based on the relationship between information about the rotation of two different wheels. In this case, the display screen may be a display screen on a display device of a computer installed outside the vehicle and connected to the network.

[0150] In this way, a person outside the vehicle who compares the two pieces of information regarding the steering wheel angle can recognize a change in direction of the vehicle or an abnormal state from the degree of difference between the two pieces of information. Also, by displaying the abnormal state of the vehicle on the display screen as described above, a person outside the vehicle can easily recognize the abnormal state of the vehicle without having to go through the trouble of determining the abnormal state themselves. Furthermore, a person outside the vehicle who views the display screen can recognize a change in the vehicle's traveling direction and determine the driving state of the vehicle based on this change in the vehicle's traveling direction, which can be useful for safe driving and eco-driving.

[0151] For example, a taxi company or a transportation company may check past or present changes in the direction of travel of a driver's vehicle on a display screen installed in the company to determine the driver's driving condition and use the information as an indicator to encourage safe and eco-friendly driving. Also, a driver may check past changes in the direction of travel of their vehicle on a display screen at home to determine the driver's driving condition and use the information as an indicator to promote safe and eco-friendly driving. In this case, as described above, an external computer may obtain information via a network and display it on the display screen, or the information may be recorded on a memory card 11 inserted in a system installed in the vehicle, and the memory card 11 may be read by an external computer to display the information on the display screen.

[0152] (c) The "at least two different wheels" that are the subject of the rotation information may be two or more. For example, information corresponding to two wheels and information corresponding to two other wheels that shows a normal value may be used, or an average of both pieces of information may be used. This enables highly accurate detection. As described above, there may be times when the wheel information shows a value that is extremely different from the others among multiple values. However, the control unit 18 can eliminate or smooth out such values ​​by calculating a normal value or an average value and using it for detection.

[0153] (d) The "information regarding a change in the vehicle's direction of travel" may be, for example, information indicating the degree of difference between information regarding the rotation of at least two wheels. For example, it may be information based on the difference between the values ​​indicated by the information regarding the rotation of the two wheels. Also, for example, it may be information based on the ratio between the values ​​indicated by the information regarding the rotation of the two wheels. Such information also provides values ​​that differ depending on the direction of travel, allowing the control unit 18 to detect a change in the direction of travel.

[0154] The control unit 18 may detect changes in the direction of travel by, for example, only detecting right or left turns at a junction. In this way, the number of directions that the control unit 18 must determine is reduced, allowing for simplified and faster processing. The change in the direction of travel may also be detected as a change in the angle of travel or a change in the steering angle. Since this system is capable of detection with the same accuracy as the steering angle, it can detect even detailed changes in the direction of travel. In this way, the control unit 18 can determine more detailed driving conditions. For example, the control unit 18 can detect changes in the direction of travel within the same lane and changes in the direction of travel when changing lanes. Furthermore, even when GPS positioning is not possible, the control unit 18 can detect changes in the direction of travel at road curves such as at overpasses, underground intersections, and tunnels.

[0155] (e) Information about the steering angle acquired from the network accurately indicates the steering angle, but information about the steering angle calculated based on the relationship between information about the rotation of at least two different wheels may differ from the actual steering angle depending on the state of the vehicle. For this reason, the control unit 18 can also detect an abnormal state of the vehicle based on the relationship between the two pieces of information, such as when the difference between the two pieces of information is greater than a threshold value previously set in the database 19.

[0156] The method for calculating the steering angle based on the relationship of information related to wheel rotation may be as follows. First, the control unit 18 creates a log that acquires steering angle information at approximately the same time and information related to the rotation of at least two different wheels at a time interval required to generate information related to changes in the vehicle's traveling direction according to the application, and stores the log in the database 19. The control unit 18 calculates a function of the correspondence between the relationship of the information related to the rotation of at least two different wheels of the vehicle in the log and the steering angle at the same time, and uses the function to calculate the steering angle based on the relationship of the information related to the wheel rotation. For example, the control unit 18 stores in the database 19 a log in which the difference or ratio between the instantaneous values ​​of the rotation speeds of two different wheels at the same time corresponds to the steering angle at that time, and then stores in the database 19 the correlation between this difference or ratio and the steering angle as a function. The function may be incorporated into the program as a mathematical formula, or a table for calculating the mapping may be created and stored, and the program may perform calculations using the table. Such a program, created based on past information, may be stored in the database 19 in advance, and the control unit 18 may operate based on the program.

[0157] The data format of the information about wheel rotation and steering wheel angle transmitted through the network may differ depending on the vehicle model. The correspondence between this information about wheel rotation and steering wheel angle is calculated in advance for each vehicle model, and a function is calculated and stored in database 19 as a program or data. The system is then provided with a function that allows control unit 18 to automatically detect and set the vehicle model, or for the user to manually set it. Control unit 18 calculates the correspondence between the set vehicle model and the information about wheel rotation and steering wheel angle. Based on the relationship between the steering wheel angle calculated in this way and the steering wheel angle acquired from the network, control unit 18 can detect abnormal vehicle conditions such as a flat tire or slippage. This enables accurate detection even if the vehicle model is different.

[0158] (f) By detecting an abnormal condition of the vehicle when the rotation speed of a particular wheel is significantly different from that of the other wheels, the control unit 18 can detect not only slippage of a particular wheel on snowy, icy or muddy roads, but also abnormal traction, punctures and abnormal tire pressure.

[0159] (g) The manner in which the control unit 18 displays the information about the rotation of the wheels on the display 5 may be any manner that allows for identification of the difference between the information about the steering angle acquired from the network that controls the vehicle and the information about the steering angle calculated based on the relationship between the information about the rotation of at least two different wheels. It is preferable to display the existence of a difference between the two pieces of information, the magnitude of the difference, or the type of abnormality estimated from the difference. In this way, it is possible to easily determine whether the vehicle is changing direction or whether an abnormality is occurring.

[0160] The information regarding the change in the vehicle's traveling direction may be displayed in a manner that allows the driver to determine the driving state of the vehicle based on the presence or absence of a change in the traveling direction. For example, the information may be displayed in a manner that allows the driver to visually grasp the instantaneous change in the traveling direction of the vehicle. This may be a symbolic display such as an arrow on the display screen, or light emitted by lamps such as LEDs located on the left and right.

[0161] The abnormal state may be displayed by a speech bubble as described above, or may be displayed by characters, figures, colors, or changes in these to indicate, for example, a flat tire, abnormal air pressure, slippage of a specific tire, etc. The abnormal state may be displayed on a display screen or by light emission from a lamp such as an LED.

[0162] Furthermore, the display may be configured to allow visual recognition of all changes in the vehicle's direction of travel over a predetermined period of time, such as a period long enough to determine whether the vehicle is repeatedly changing lanes in a short period of time or whether the vehicle is frequently changing direction within the same lane.

[0163] The driving state of the vehicle determined by the vehicle occupants or a person outside the vehicle may be, for example, a driving state that is compatible with or contrary to safe driving or eco-driving. This can be linked to, for example, realizing safe driving or eco-driving by the vehicle driver. For example, repeated lane changes in a short period of time may be determined by the vehicle occupants or a person outside the vehicle as a driving state of frequent overtaking. For example, frequent changes in direction within the same lane may be determined by the vehicle occupants or a person outside the vehicle as a driving state of drunk driving or drowsy driving.

[0164] As a display that can determine the driving condition, it is preferable to display, for example, a graph showing changes in the direction of travel or steering angle over a specified period of time, or numbers showing the frequency of changes in the direction of travel or steering angle over a specified period of time.

[0165] (h) The control unit 18 may determine the driving state of the vehicle based on the information regarding the change in the vehicle's traveling direction as described above, and may control the display of the driving state on the display screen of the display device 5. In this way, the vehicle occupants, including the driver, or persons outside the vehicle who view the display screen can easily recognize the driving state of the vehicle without having to go through the trouble of determining the driving state themselves. The display of the driving state may be, for example, a display that can be recognized by letters, figures, colors, or changes in these, such as danger, safety, drowsiness, drinking, etc.

[0166] (i) The control unit 18 may acquire information about the driving operation of the vehicle via the network, and may perform control to display the acquired information about the driving operation of the vehicle together with information about changes in the vehicle's traveling direction on the display screen of the display device 5. In this way, information about the driving operation of the vehicle is displayed together with information about changes in the vehicle's traveling direction, so that passengers in the vehicle, including the driver, or people outside the vehicle who view the display screen can determine the driving state of the vehicle in more detail based on the relationship between changes in the traveling direction and information about the driving operation.

[0167] The information regarding the vehicle driving operation may be, for example, information indicating whether or not a member or mechanism that needs to be operated by the driver while driving has been operated and the timing of such operation. For example, the information regarding the vehicle driving operation may include information such as when a turn signal was turned on, when and how many times the brake was applied, and when and how many times the accelerator was applied. For example, if a turn signal is not turned on before turning right or left, it may be determined that the driving condition is dangerous. For example, if the brake is not applied before turning right or left, and the accelerator is applied, it may be determined that the driving condition is dangerous.

[0168] (j) The control unit 18 may acquire information related to the driving operation of the vehicle, determine the driving state of the vehicle based on the acquired information related to the driving operation of the vehicle and information related to changes in the traveling direction of the vehicle, and perform control to display the driving state on the display screen of the display device 5. In this way, passengers in the vehicle, including the driver, or people outside the vehicle who view the display screen can easily obtain detailed information about the driving state without having to go through the trouble of determining the driving state themselves.

[0169] (k) The control unit 18 may control the speaker 16 to output a sound depending on an abnormal state or driving condition. In this way, by outputting a sound, it is possible to reliably notify vehicle occupants or outsiders who are not looking at the display screen of an abnormal state of the vehicle. For example, it is possible to make vehicle occupants or outsiders aware of a flat tire, abnormal air pressure, slippage of a specific tire, etc. Furthermore, by outputting a sound, it is possible to reliably notify vehicle occupants or outsiders who are not looking at the display screen of the driving condition of the vehicle. For example, it is possible to warn vehicle occupants or outsiders of the vehicle of the dangers of drowsy driving or drunk driving.

[0170] (l) When judging whether a value is greater than or equal to a threshold value for detecting right / left turns or abnormal conditions, or when judging whether a value matches or does not match, it is up to the discretion of the judge to use terms such as "greater than" or "less than," or to use terms such as "greater than," "less than," "exceeds," "does not exceed," "is above," "is below," or "is less than." Therefore, for example, depending on the value settings, it is essentially the same to read "greater than" as "greater than," "exceeds," or "above," and "less than" as "smaller than," "does not exceed," "is below," or "is less than."

[0171] (m) The control unit 18 may be set not to detect the direction of travel of the vehicle when the ABS function is activated. When the ABS is activated, the direction of travel cannot be accurately detected using signals from the sensors. Therefore, by having the control unit 18 not perform detection in such cases, it is possible to prevent erroneous judgments and erroneous operations due to erroneous detection.

[0172] (n) The control means may be realized by one control unit 18 or by multiple control units 18. The entire control unit 18 may be located inside the vehicle, the entire control unit 18 may be located outside the vehicle, or part of the control unit 18 may be located inside the vehicle and the remaining part may be located outside the vehicle. A system may be configured in which at least part of the functions of the control unit 18 are located on a server, the server executes the functions, and the electronic device carried by the user acquires the execution results. Also, some or all of the information to be registered in the database may be registered on the server. A radar detector or other electronic device or apparatus may have a function to communicate with the server, and the control unit may access the server as needed, acquire necessary information, and execute processing.

[0173] (o) The display 5 as a display means may be any display device capable of displaying information that can be visually recognized by the user, etc., including any display device such as a liquid crystal or organic electroluminescence (EL) display screen. Such a display means may be realized by a display device of a computer installed outside the vehicle and connected to a network, as described above. The speaker 16 (including headphones, earphones, etc.) as a sound output means may also be realized by an output device of a computer installed outside the vehicle and connected to a network.

[0174] (p) The system to which the present invention is applied is not limited to the radar detector 1. The present invention can be applied to various types of in-vehicle electronic devices, such as car navigation systems and drive recorders. The functions of the present invention can be easily added by installing a program into an existing system configured as an electronic device. Therefore, vehicle owners can use new functions while keeping costs down.

[0175] (q) The functions of the system of the present invention are configured as a program to be implemented by a computer provided in the control unit 18, but this is not limited to this, and the program may be distributed among multiple computers for distributed processing. [Explanation of symbols]

[0176] 1. Radar detector 2...Case body 3...Bracket 5...Indicator 6...Touch panel 7...Volume adjustment button 8...Work buttons 10...Memory card reader 11...Memory card 12...DC jack 13...GPS receiver 14...Microwave receiver 15...Radio receiver 16...Speaker 18...Control unit 19...Database 22...Connection cable 23...Plug 25...Connector terminal 24...Socket 31...Lamp 32...Remote control receiver 33...Remote control 34...Infrared communication device 35...Mobile phone 36...Geomagnetic sensor 37...Accelerometer 111...Car icon 112...Target icon 121…Current time 122...GPS signal reception level icon 123...No parking area icon 124…Reception sensitivity mode display icon 125...Vehicle speed 126…Compass needle 130,131…GPS alarm display

Claims

1. A system that acquires information about wheel rotation from an external network that collects data while the vehicle is running, and has the function of displaying the information on a display screen of a computer that is installed outside the vehicle and connected to the network, so that a person outside the vehicle can compare information about steering angle acquired from the network that controls the vehicle with information about steering angle calculated based on the relationship between information about the rotation of at least two different wheels.

2. The system according to claim 1, further comprising a function for displaying information that can distinguish between information regarding a steering wheel angle obtained from a network that controls the vehicle and information regarding a steering wheel angle calculated based on the relationship between information regarding the rotation of the at least two different wheels.

3. The system according to claim 2 , further comprising a function of displaying the existence of the difference as a mode for identifying the difference.

4. 4. The system according to claim 2, further comprising a function of displaying the magnitude of the difference as a way of identifying the difference.

5. 5. The system according to claim 2, further comprising a function for displaying the type of abnormality estimated from the difference, as a mode for identifying the difference.

6. 6. The system according to claim 1, further comprising a function of displaying on the display screen a change in the traveling direction of the vehicle so that the change can be recognized.

7. 7. The system according to claim 1, wherein the display screen is a display screen installed in a taxi company or a transportation company.

8. A program for causing a computer to realize the functions of the system according to any one of claims 1 to 7.

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