JP2011002355A - Navigation device and vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a navigation device and a vehicle control device which determines reliability of detected present place information.SOLUTION: A sensor fusion part 21 obtains the newest detection value detected by sensors 22a-22d, and detects a present place. Then, the sensor fusion part 21 calculates each sensor error and an index value showing sureness of the detected present place, and outputs the index value to a determination part 24. A sensor monitoring part 23 monitors each state of the sensors 22a-22d, and outputs an abnormality signal to the determination part 24 when a specific sensor is in an abnormal state. First of all, the determination part 24 examines whether the index value output from the sensor fusion part 21 is higher than a prescribed threshold or not. When it is higher, the determination part 24 cuts off a switch 25, and prevents output of present place information to one's own vehicle 2. Meanwhile, when the index value is lower than the prescribed threshold, the determination part 24 predicts an index value after a fixed time, When the index value after the fixed time is higher than the threshold, the determination part 24 informs the own vehicle 2 of the time.

Description

  The present invention relates to a navigation device and a vehicle control device having a function of detecting a current location.

  Various sensors such as a speed sensor and an acceleration sensor are mounted on current navigation devices and vehicles. The navigation device and the vehicle control device perform predetermined control based on information output from these sensors. Among such devices, there are devices that recognize the surrounding environment from information output from the sensor and notify the user that the control is stopped when it is determined that the environment is difficult to control. To do. For example, Patent Document 1 discloses a vehicle driving support device that recognizes a road condition during traveling and notifies the driver that the control may be stopped if there is a possibility that the driving support control may be hindered. It is shown.

JP 2003-205805 A

  In the prior art, a road condition is recognized based on information obtained from a sensor, and it is determined whether or not the road condition can be correctly recognized in the future. However, it does not take into account that the reliability of the information itself obtained from the sensor decreases, for example, the accuracy of the sensor decreases due to a failure. Therefore, if such a failure occurs, it is impossible to obtain a behavior expected.

The invention according to claim 1 detects the present location by executing input of a plurality of detection values respectively output from a plurality of sensors and predetermined sensor fusion processing based on the plurality of detection values. Based on the current location detection means, error calculation means for calculating error information representing errors of the plurality of detection values based on the current location, the plurality of detection values, and the probability of the current location based on the error information. A navigation apparatus comprising: index value calculating means for calculating an index value representing the position; and reliability determining means for determining the reliability of the current location based on the index value.
The invention according to claim 9 is the vehicle control device using the output signal from the navigation device according to any one of claims 4 to 8 as one of the vehicle control signals.

  According to the present invention, it is possible to accurately determine the reliability of the detected current location information even when some of the plurality of sensors are abnormal.

It is a block diagram which shows the whole structure of the navigation apparatus in 1st Embodiment. Is a flowchart showing the detecting process of the current position by the navigation apparatus in the first embodiment. It is a flowchart which shows the detection process of the present location by the navigation apparatus in 2nd Embodiment. Is a flowchart showing the detecting process of the current position by the navigation apparatus in the third embodiment. It is a block diagram which shows the whole structure of the navigation apparatus in 4th Embodiment. Is a flowchart showing the detecting process of the current position by the navigation apparatus in the fourth embodiment.

-First embodiment-
FIG. 1 is a block diagram showing the overall configuration of the navigation device according to this embodiment.

  The navigation device 1 includes a control circuit 11, a storage device 12, a display monitor 13, an input device 14, a touch panel control unit 15, a touch panel 16, a sensor fusion unit 21, a vibration gyro 22a, a speed sensor 22b, an acceleration sensor 22c, a GPS sensor 22d, A sensor monitoring unit 23 and a determination unit 24 are included.

  The control circuit 11 includes a microprocessor and its peripheral circuits, and performs various controls by executing a control program stored in the storage device 12. The storage device 12 is a ROM that stores a control program, a RAM that is used as a work area for the control program, an HDD that stores map data, and the like. When the control circuit 11 performs a predetermined route search process based on the map data stored in the storage device 12, the processing result is displayed on the display monitor 13 as a recommended route.

  Map data stored in the storage unit 12 includes map display data, and route search data. The map display data and the route search data include road link information and node information stored in the map data. The link information, travel time of each link (below, link travel time) contains the information of. The map display data has map data of a plurality of scales from wide areas to details, and the scale of the display map can be changed according to a user request. The storage device 12 in which the map data is stored may be a recording medium other than the HDD, such as a DVD-ROM or a CD-ROM.

  The display monitor 13 provides the user with various information such as a road map near the vehicle position as a screen display based on various information such as map data. The input device 14 has an input switch for a user to set various commands, and is realized by an operation panel, a remote controller, or the like. The user sets the destination by operating the input device 14 in accordance with instructions on the display screen of the display monitor 13.

  The touch panel 16 is a transparent touch switch laminated on the surface of the display monitor 13, and an image displayed on the display monitor 13 is displayed through the touch panel 16. The touch panel 16 sends a signal corresponding to the operation position on the touch panel 16 to the touch panel control unit 15. Then, the touch panel control unit 15 calculates the pressed position of the touch panel 16.

  The sensor fusion unit 21 is a circuit that detects the current location of the vehicle based on sensor values acquired from the plurality of sensors (22a to 22d). The current location information including the current location detected by the sensor fusion unit 21 is output to the control circuit 11. The control circuit 11 determines a map display range, a route search start point, and the like based on the current location information, and displays the current location on the map.

  In addition to the above processing, the control circuit 11 outputs the current location information output from the sensor fusion unit 21 to the host vehicle 2 via the switch 25. The own vehicle 2 uses the current location information output from the control circuit 11 to execute vehicle control such as automatically decelerating before a sharp curve or automatically stopping before a temporary stop line.

  The sensors used by the sensor fusion unit 21 are a vibration gyro 22a, a speed sensor 22b, an acceleration sensor 22c, and a GPS (Global Positioning System) sensor 22d. The sensor fusion unit 21 may use a sensor other than these in order to detect the current location. The sensor fusion unit 21 acquires the latest detection value detected by these sensors each time a predetermined time elapses or travels a predetermined distance, and detects the current location. In this embodiment, it detects the current position from the detection value of each sensor using a Kalman filter.

  The vibration gyro 22a is a sensor for acquiring the traveling direction of the vehicle, the speed sensor 22b is a sensor for acquiring the speed of the vehicle, and the acceleration sensor 22c is a sensor for acquiring the acceleration of the vehicle. The GPS sensor 22d detects a GPS signal from a GPS satellite.

  After detecting the current location, the sensor fusion unit 21 calculates an error included in the detection value of each sensor with respect to the current location. In this embodiment, this error is the value of the error covariance matrix used in the Kalman filter.

  Next, the sensor fusion unit 21 uses the error in each sensor and the detected current location to calculate an index value representing the probability of the detected current location, and outputs it to the determination unit 24. This index value is a numerical value that decreases when the probability that the detected current location is different from the actual current location is low, and increases when the probability that the detected current location is different from the actual current location is high. That is, if the detected current location has high reliability, the index value becomes low. In this embodiment, the Mahalanobis distance of the detection value of each sensor with respect to the current location is calculated and used as an index value.

  Sensor monitoring unit 23 monitors the state of each of the sensor the sensor fusion unit 21 is used. When it is detected that a specific sensor is in an abnormal state, an abnormal signal is output to the determination unit 24. The abnormal state is, for example, that the sensor does not output the detection value for a certain period, the sensor does not output the detection value at the timing when the detection value should be output, or the detection value including an obvious error for a certain period has been continuously output. States. Whether or not a certain detection value includes an obvious error may be determined, for example, based on whether or not the detection value is included in a predetermined range, or detection estimated from the current location calculated by the sensor fusion unit 21 You may determine by the difference with a value exceeding a predetermined threshold value.

  The determination unit 24 first checks whether or not the index value output from the sensor fusion unit 21 exceeds a predetermined threshold value. If the index value exceeds a predetermined threshold value, the current location information output from the sensor fusion unit 21 is determined to be unreliable information, and the switch 25 is shut off. As a result, the current location information is not output to the host vehicle 2, and the host vehicle 2 does not perform control using the current location information.

  On the other hand, when the index value is equal to or less than the predetermined threshold value, the determination unit 24 determines whether the index value is output from the sensor fusion unit 21 and the signal output from the sensor monitoring unit 23 after a predetermined time. The index value of is predicted. This prediction is made on the assumption that the state of the sensor does not change from the current state. That is, the determination unit 24 predicts how the index value changes when the host vehicle continues to travel for a certain period of time in the current state. When it is predicted that the index value exceeds the threshold value after a certain time, the host vehicle 2 is notified that the index value exceeds the threshold value after a certain time. In response to this notification, the host vehicle 2 notifies the user that the current location information of the vehicle cannot be used, or automatically stops the control after a certain time.

  After the switch 25 is shut off by the determination unit 24, when the cause of the switch 25 being shut off is resolved, the determination unit 24 connects the switch 25 again. As a result, the current location information is output to the own vehicle 2 again. For example, when the switch 25 is shut off because a specific sensor continues to output a detection value including an obvious error for a certain period, the determination is made when this sensor outputs a correct detection value again. The switch 25 is connected by the unit 24.

  It should be noted that a certain interval may be provided after the switch 25 is shut off until it is connected again. For example, even if the index value is temporarily increased and the switch 25 is shut off, and the index value drops below the threshold value after 1 second, the switch 25 remains connected until at least 5 seconds have passed. It may not be done.

  Next, the current location detection process by the navigation device 1 will be described with reference to the drawings. FIG. 2 is a flowchart showing the current location detection process performed by the navigation device 1. First, in step S11, the latest detection value is acquired from the sensors 22a to 22d. In step S12, a Kalman filter is applied to the detection value acquired from the sensor to calculate the current location. At step S13, and outputs the current position calculated in step S12 as a location to the vehicle 2. In step S14, it calculates an error covariance matrix using a detection value obtained from the sensor.

  In step S15, the Mahalanobis distance of the error covariance matrix calculated in step S14 is calculated and used as an index value of the detected current location. In step S16, it is determined whether or not the index value calculated in step S15 exceeds a predetermined threshold value. When the index value is larger than the threshold value, an affirmative determination is made in step S16, and the process proceeds to step S17. In step S17, the current location information output from the sensor fusion unit 21 to the host vehicle 2 is blocked, and the process ends. On the other hand, if a negative determination is made by the step S16, the process proceeds to step S18.

  At step S18, it determines whether the sensor monitoring unit 23 is notified of the abnormality of the sensor. If the sensor monitoring unit 23 does not output an abnormal signal, a negative determination is made in step S18, and the process ends. On the other hand, if the determination is affirmative in step S18, the process proceeds to step S19.

  In step S19, an index value after a predetermined time is predicted based on the index value and the model of the host vehicle 2 used for detection of the current location. In step S20, it is determined whether or not the index value is predicted to be larger than the threshold value within a certain period. When it is predicted that the index value will be larger than the threshold value, an affirmative determination is made in step S20, and the process proceeds to step S21. In step S21, the time when the index value is expected to be larger than the threshold value is output to the host vehicle 2, and the process ends. On the other hand, if a negative determination is made by the step S20, the process ends.

According to the navigation apparatus according to the first embodiment described above, the following operational effects can be obtained.
(1) The sensor fusion unit 21 detects the current location by executing sensor fusion processing based on a plurality of detection values respectively output from the plurality of sensors 22a to 22d. Then, based on the detected current value, an error of a plurality of detected values corresponding to each sensor is calculated, and then an index value representing the probability of the current location is calculated. The determination unit 24 determines the reliability of the detected current location based on the index value. Thereby, it is possible to recognize how certain the detected current location is.

(2) The determination unit 24 determines the reliability of the detected current location by predicting an index value after a predetermined time from the current time. Thereby, it is possible to grasp in advance whether the current location detected in the future is reliable.

(3) The sensor monitoring unit 23 monitors the states of the sensors 22a to 22d, and when there is an abnormal sensor, notifies the determination unit 24 to that effect. Upon receiving this notification, the determination unit 24 determines the reliability of the current location detected by predicting the index value. Thereby, the influence on the reliability of the present location by the failure of a sensor etc. can be confirmed at an early stage.

(4) The control circuit 11 outputs the current location where the sensor fusion unit 21 is detected to the host vehicle 2, and the determination unit 24 predicts that the index value exceeds a predetermined threshold value within a predetermined time. The time when the value exceeds the threshold value is output to the host vehicle 2. Thereby, the own vehicle 2 can notify a user in advance that there is a possibility of stopping the control.

(5) When the index value exceeds a predetermined threshold value, the determination unit 24 determines that the detected current location is not reliable, and blocks the current location information output from the control circuit 11 to the host vehicle 2. Thereby, it can avoid that the own vehicle 2 performs control using the present location information which was largely incorrect.

(6) The determination unit 24 releases the blocking of the current location information output from the control circuit 11 to the host vehicle 2 when the index value becomes equal to or less than the threshold value after blocking the current location information. Thereby, even when the sensor is temporarily abnormal due to noise or the like, the host vehicle 2 can start the control again.

  In the first embodiment described above, the sensor monitoring result is used for predicting the index value. In the second embodiment described in detail below, the sensor monitoring result is used to calculate the sensor error.

-Second embodiment-
FIG. 3 is a flowchart showing a current position detection process performed by the navigation device according to the second embodiment. The difference from the processing of the navigation device in the first embodiment shown in FIG. 2 is in step S34 and step 38.

  In step S34, instead of the error covariance matrix, the difference between the detected value of the sensor and the detected value that the sensor would output is taken and used as the sensor error. At this time, if the sensor monitoring unit notifies the abnormality of the sensor, the detection value of the corresponding sensor is treated as including a large error. In the first embodiment, there is a branch based on the monitoring result of the sensor before the index value is predicted. However, there is no such branch before step S38 in the present embodiment.

  According to the navigation device according to the second embodiment described above, the same operation and effect as those obtained with the navigation device according to the first embodiment can be obtained.

  In the second embodiment described above, the sensor monitoring result is used for predicting the index value. In the third embodiment described in detail below, the monitoring result of the sensor is used for calculating the error of the sensor.

--Third embodiment--
FIG. 4 is a flowchart showing a current position detection process performed by the navigation device according to the third embodiment. The difference from the processing of the navigation device in the second embodiment shown in FIG. 3 is in step S44 and step 45.

  In step S44, unlike step S34, the sensor monitoring unit does not use the abnormality notification and determines the sensor error. Instead, in step S45, the index value is calculated in consideration of the notification from the sensor monitoring unit.

  According to the navigation device according to the third embodiment described above, the same operational effects as those obtained with the navigation device according to the second embodiment can be obtained.

  In the above-described third embodiment, the current location information is blocked based on sensor monitoring and index values. In the fourth embodiment described in detail below, the sensor monitoring result is used to calculate the sensor error.

-Fourth embodiment-
FIG. 5 is a block diagram showing the overall configuration of the navigation device according to the fourth embodiment. Unlike the navigation device 1 in the first embodiment, the navigation device 101 does not have a sensor monitoring unit that monitors the state of the sensor and a switch for blocking output of current location information to the host vehicle.

  Figure 6 is a flowchart showing the detecting process of the current position by the navigation apparatus in the fourth embodiment. First, in step S51, the latest detection value is acquired from the sensors 22a to 22d. In step S52, the Kalman filter is applied to the detection value acquired from the sensor to calculate the current location. At step S53, and outputs the current position calculated in step S52 as a location to the vehicle 2. In step S54, the difference between the detected value of the sensor and the detected value that the sensor will output is calculated, and the error of the sensor is calculated.

  In step S55, the index value of the current location detected in step S52 is calculated using the sensor error calculated in step S54. In step S56, an index value after a predetermined time is predicted based on the index value and the model of the host vehicle 102 used for detecting the current location. In step S57, it is determined whether or not the index value is predicted to be larger than the threshold value within a certain period. When it is predicted that the index value will be larger than the threshold value, an affirmative determination is made in step S57, and the process proceeds to step S58. In step S58, the time when the index value is expected to be larger than the threshold value is output to the host vehicle 102, and the process is terminated. On the other hand, if a negative determination is made in step S57, the process ends.

  In the present embodiment, the navigation device 101 continues outputting the current location information to the host vehicle 102 no matter how many errors are included in the current location information. The own vehicle 102 determines whether to use the current location information transmitted from the navigation device 101 based on the information output by the determination unit 124. In addition, when the determination unit 124 outputs the time when the index value is expected to be larger than the threshold value to the own vehicle 102, information indicating whether or not the current index value is larger than the threshold value is also included. It may be output.

According to the navigation device according to the fourth embodiment described above, the following operation and effect are obtained in addition to the operation and effect obtained by the navigation device according to the third embodiment.
(1) The current location information output from the control circuit 111 is always input to the host vehicle 102 and is not blocked by the determination unit 124. Thereby, the own vehicle 2 can freely determine whether or not the control is continued.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(1) The sensor fusion unit may use an algorithm other than the Kalman filter for detecting the current location. For example, the current location may be detected by a Bayes filter, a least square method, maximum likelihood estimation, or the like.

(2) A value other than the error covariance matrix may be used as the sensor error. For example, the difference between the estimated value and the detected value of the sensor may be the sensor error, and the variance of the detected value of the sensor may be the sensor error.

(3) A value other than the Mahalanobis distance may be used as the index value. For example, a variance value of sensor detection values may be used as an index value, and an S / N ratio of sensor detection values may be used as an index value.

(4) The determination unit 24 may output information other than the time at which the index value exceeds the threshold value to the host vehicle 2. For example, a binary value indicating whether the current location is reliable may be output, or a numerical value indicating the reliability of the current location may be output.

(5) Any navigation device that calculates the current location using a plurality of sensors may be used for in-vehicle use. In addition, the reliability determination result may be output to a device other than the vehicle. For example, a portable PND (Personal Navigation Device) that displays the reliability of the current location on a liquid crystal monitor may be used.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1,101 Navigation apparatus 2,102 Own vehicle 11,111 Control circuit 21 Sensor fusion part 22a Vibration gyro 22b Speed sensor 22c Acceleration sensor 22d GPS sensor 24,124 Determination part

Claims (10)

Input means for inputting a plurality of detection values respectively output from a plurality of sensors;
A current position detecting means for detecting a current position by executing a predetermined sensor fusion process based on the plurality of detection values;
Error calculation means for calculating error information representing errors of the plurality of detection values based on the current location;
Index value calculation means for calculating an index value representing the probability of the current location based on the plurality of detection values and the error information;
Reliability determination means for determining the reliability of the current location based on the index value;
A navigation device comprising: The navigation device according to claim 1, wherein
Index value predicting means for predicting an index value after a predetermined time from the current time based on the index value calculated by the index value calculating means,
The navigation apparatus according to claim 1, wherein the reliability determination unit determines the reliability of the current location based on the index value predicted by the index value prediction unit. The navigation device according to claim 1 or 2,
Further comprising a state identifying means for identifying the states of the plurality of sensors,
The navigation apparatus according to claim 1, wherein the reliability determination unit determines the reliability of the current location by using the states of the plurality of sensors identified by the state identification unit. In the navigation device according to any one of claims 1 to 3,
A navigation device that outputs the current location to a vehicle on which the navigation device is mounted when the reliability determination means determines that the reliability of the current location is reliable. The navigation device according to any one of claims 1 to 4,
The said reliability judgment means outputs the result which judged the reliability of the said present location to the vehicle by which the said navigation apparatus is mounted, The navigation apparatus characterized by the above-mentioned. The navigation device according to claim 5, wherein
The reliability judgment means outputs the prediction result by the index value prediction means to the vehicle when the index value prediction means predicts that the index value exceeds a predetermined threshold value within a predetermined time from the present time. A navigation device characterized by that. The navigation device according to claim 5, wherein
The reliability determination means outputs information indicating that the current location is reliable to the vehicle while the index value prediction means predicts that the index value does not exceed a predetermined threshold value within a predetermined time from the present time. A navigation device characterized by continuing to do so. In the navigation device according to any one of claims 5 to 7,
The navigation apparatus according to claim 1, wherein the current position detecting means cuts off the output of the current position to the vehicle when the reliability determining means determines that the current position is unreliable. The navigation device according to claim 8, wherein
The current location detection means restarts the output of the current location to the vehicle when the reliability determination means determines that the current location is reliable after blocking the output of the current location. Navigation device.   The vehicle control apparatus characterized by using an output signal from the navigation apparatus according to any one of claims 5 to 9 as one of the vehicle control signals.

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