JP2010008095A - Own vehicle position correcting system and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the accuracy of detecting own vehicle position, even when unstable vehicle behavior is produced, when the vehicle travels on a road of low friction coefficient. <P>SOLUTION: Own vehicle position correction system includes: a distance sensor (2) for detecting the travel distance of own vehicle; a direction sensor (3) for detecting the direction of own vehicle; a GPS sensor (4) for receiving a GPS signal and detecting the position of own vehicle; a detection mechanism (5) for condition which has effect on the accuracy of own vehicle position; a position correction means (1a) for correcting the position of own vehicle calculated through the detection outputs of the distance sensor, the direction sensor, and the GPS sensor; and a control means (1b) for controlling the position correction means, on the basis of the detection result of the detection mechanism. The control means controls the position correction means so that own vehicle position correction is performed, with smaller weights carried by the detection outputs of the distance sensor and the direction sensor over a predetermined section, when a condition which has effect on the accuracy of own vehicle position is detected than when the condition is not detected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle position correction system and a program for traveling on a road surface having a low friction coefficient.

Conventionally, in a navigation device for a vehicle, a GPS (Groval Positioning System) sensor, a distance sensor composed of a vehicle speed sensor and an acceleration sensor for detecting the rotational speed of a wheel, and a direction sensor such as a gyro depart from the relative movement distance and the relative movement direction. A technique for calculating the current position of a vehicle by accumulating from a point is known. However, when traveling on a road surface with a low coefficient of friction such as a snowy road, a frozen road, and an unpaved road, a slippage or idling of a wheel occurs and a position detection error occurs. Therefore, when the current position of the vehicle is calculated by counting the number of wheel rotations and multiplying the count value by the distance correction coefficient to determine the current position of the vehicle, the current movement distance per unit time calculated from the number of wheel rotations Calculate the difference (acceleration) of the movement distance from the (speed) and the previous movement distance (speed) per unit time, and if the acceleration is within the allowable limit value, the vehicle will run without slipping or idling, When the acceleration deviates from the allowable limit value, it is determined that the wheel has slipped or slipped, and the movement distance is calculated by regarding the value obtained by adding the allowable limit value to the previous movement distance per unit time as the current movement distance. Has been proposed (Patent Document 1).
JP-A-8-61965

  However, the method of Patent Document 1 determines that the tire has slipped or slipped when the acceleration deviates from the allowable limit value, and calculates the speed using the allowable limit value. In this case, since the behavior of the vehicle becomes unstable depending on which wheel slips, even if the speed is calculated simply using the allowable limit value, there is a limit to improving the detection accuracy of the own vehicle position.

An object of the present invention is to solve the above-described problems, and it is an object of the present invention to perform position correction with high accuracy even when the vehicle travels on a road surface with a low coefficient of friction and the vehicle behaves unstablely.
The present invention affects a distance sensor that detects the travel distance of the host vehicle, a direction sensor that detects the direction of the host vehicle, a GPS sensor that receives a GPS signal and detects the position of the host vehicle, and the position accuracy of the host vehicle. A position detecting means for correcting the position of the vehicle calculated by the detection output of the distance sensor, the direction sensor, and the GPS sensor, and the position correcting means based on the detection result of the detecting mechanism. Control means, and the control means weights the detection outputs of the constant section distance sensor and the azimuth sensor when a situation that affects the vehicle position accuracy is detected by the detection mechanism than when the situation is not detected. The position correction means is controlled so as to make the vehicle position correction smaller.
In addition, the present invention provides a step of detecting a situation that affects the vehicle position accuracy, and when detecting a situation that affects the vehicle position accuracy, the distance between the fixed section distance sensor and the azimuth sensor is greater than when the situation is not detected. It is characterized by causing the computer to execute the step of correcting the vehicle position by reducing the weight of the detection output.

  The present invention can accurately perform position correction even when the vehicle travels on a road with a low coefficient of friction or the like and the vehicle behaves unstablely.

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram showing an example of the vehicle position correction system of the present embodiment.
In a normal state, the control device 1 including a computer that controls the entire system calculates the position of the vehicle based on the detection outputs of the distance sensor 2, the direction sensor 3, and the GPS sensor 4, and the behavior of the vehicle and snowfall described later Position correction means 1a for calculating the position of the vehicle by correcting the weight of the detection output of the distance sensor 2 and the direction sensor 3 smaller than that in a normal state in a certain section and correcting the position obtained last time. The control means 1b for controlling the position correction processing by the position correction means 1a is provided.

The situation detection mechanism 5 is a mechanism that detects whether or not a situation that adversely affects the detection accuracy of the vehicle position by the distance sensor, the azimuth sensor, and the GPS sensor has occurred.
(A) A mechanism that detects a side slip when turning from a wheel speed sensor, a rudder angle sensor, a lateral acceleration sensor, etc., and brakes the inner or outer front wheel or rear wheel to prevent the side slip, and monitors the wheel rotation. The operation of a vehicle stabilizer such as an anti-lock brake system that releases the brake by lowering the hydraulic pressure by judging that the brake is locked when it detects that the other wheels are rotating but not a specific wheel. (B) The tire idling, that is, the wheel spin at the time of starting and acceleration, which is grasped from the vehicle speed and the rotational speed of each tire, is detected, that is, wheel spin is detected, and the driving force transmitted to the driving wheel causing the idling is adjusted. The traction control etc. which cancels the idling state is activated. (C) Normally, it runs on two-wheel drive, and when the driving wheel idles, the standby 4WD system transmits the driving force to the remaining two wheels. Transition to four-wheel drive (d) Acquires temperature conditions and snowy weather information around the vehicle position where the road surface may freeze by using a temperature sensor and a communication device that obtains traffic information to be distributed Control On the premise that the wheel is traveling without slipping by gripping the road surface, the device 1 is controlled at a predetermined timing by a distance sensor 2 composed of a vehicle speed sensor and an acceleration sensor, an azimuth sensor 3 composed of a gyro and the like, and a GPS sensor 4. The current position is calculated every time, and the previously calculated position is corrected. However, when the situations (i) to (d) are detected by the situation detection mechanism 5, wheel slip or the like occurs, and an accurate detection output cannot be obtained from the distance sensor 2. Therefore, when (i) to (d) are detected by the situation detection mechanism 5, the position correction means 1a is more in the fixed section, the distance sensor 2, and the direction sensor 3 than when (b) to (d) are not detected. The current position is calculated by decreasing the weight of the detection output and increasing the weight of the detection output of the GPS sensor 4. The GPS sensor receives radio waves from multiple satellites, calculates the current position based on the principle of triangulation, and outputs it. Regardless of the slipping of the wheels, regardless of the above situations (a) to (d) This is because the vehicle position can be obtained. Note that the current position may be calculated based on only the detection output of the GPS sensor 4 without using the detection output of the fixed section, the distance sensor 2 and the direction sensor 3.

  With such control, the control device 1 that can obtain the current position with high accuracy regardless of changes in the situation reads various data such as map data, road data, and facility data stored in the storage device 6. It also has a function of displaying and guiding on the display device 7 and using the current position information calculated as described above, performing map matching to display the current vehicle position on the map and displaying surrounding facilities and the like I will guide you. At this time, the driver may be informed to the display device of which sensor weighting is reduced or increased to guide the display device.

Next, detection and position correction by the situation detection mechanism when traveling on a low friction road surface will be described with reference to FIGS.
In FIG. 2, if the vehicle 10 is traveling on the road 20 and detects any of the above conditions (A) to (D) at the position P1, the distance sensor and the direction sensor are The position correction is performed by decreasing the weight of the detection output and increasing the weight of the detection output of the GPS sensor. If any one of the above conditions (a) to (d) is not detected for a certain period L from the position P1, the current position correction method is restored to the original position at the position P2 that is a certain distance L from P1. Position correction is performed based on the detection output of the sensor, direction sensor, and GPS sensor. When the vehicle further travels and any of the above situations (a) to (d) is detected at the position P3, the weights of the detection outputs of the distance sensor and the azimuth sensor are reduced between the position P3 and the fixed section L. Then, the position correction is performed by increasing the weight of the detection output of the GPS sensor.

  In FIG. 3, if any one of the above conditions (A) to (D) is detected at the vehicle position P1, the weights of the detection outputs of the distance sensor and the azimuth sensor are reduced during the certain section L from the vehicle position P1. The position is corrected by increasing the weight of the detection output of the GPS sensor. If any one of the above conditions (a) to (d) is not detected for a certain period L from the position P1, the current position correction method is restored. In the case of FIG. Since any one of the above conditions (A) to (D) is newly detected at the position P4, the weights of the detection outputs of the distance sensor and the azimuth sensor are reduced during the certain period L from the position P4, and the GPS sensor The position is corrected by increasing the weight of the detection output. Then, since any one of the above conditions (A) to (D) is detected at the position P5 in the fixed section, the detection output of the distance sensor and the azimuth sensor is weighted from the position P5 to the fixed section L. The position is corrected by reducing the weight and increasing the weight of the detection output of the GPS sensor.

It is a block diagram which shows the example of the own vehicle position correction system of this embodiment. It is a figure explaining the detection and position correction by a condition detection mechanism. It is a figure explaining the detection and position correction by a condition detection mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Control apparatus, 1a ... Position correction means, 1b ... Control means, 2 ... Distance sensor, 3 ... Direction sensor, 4 ... GPS sensor, 5 ... Situation detection mechanism, 6 ... Memory | storage device, 7 ... Display apparatus.

Claims (4)

A distance sensor that detects the travel distance of the vehicle;
A direction sensor that detects the direction of the vehicle,
A GPS sensor that receives a GPS signal and detects the position of the vehicle;
A detection mechanism that affects the vehicle position accuracy,
A position correction means for correcting the vehicle position calculated by the detection output of the distance sensor, the direction sensor, and the GPS sensor;
Control means for controlling the position correction means based on the detection result of the detection mechanism,
When the control unit detects a situation that affects the vehicle position accuracy by the detection mechanism, the weight of the detection output of the constant section distance sensor and the azimuth sensor is made smaller than when the situation is not detected. An own vehicle position correction system characterized by controlling position correction means to perform correction. Detection of the situation affecting the vehicle position accuracy by the detection mechanism includes detection of vehicle stabilizer operation, detection of wheel spin, detection of four-wheel drive in a standby type 4WD vehicle, and acquisition of weather information such as low outside temperature and snowfall. The own vehicle position correcting system according to claim 1, wherein: When detecting a situation that affects the vehicle position accuracy within the fixed section, the control means corrects the vehicle position by reducing the weights of the detection outputs of the fixed section distance sensor and the direction sensor from the detected position. 2. The vehicle position correction system according to claim 1, wherein the position correction means is controlled as described above. Detecting a situation that affects the vehicle position accuracy;
When detecting a situation that affects the vehicle position accuracy, performing a correction of the vehicle position by reducing the weighting of the detection output of the constant section distance sensor and the azimuth sensor compared to when not detecting the situation;
A program that causes a computer to execute.

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