JP2011140270A - Parking assistance device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking assistance device appropriately assisting parking when retreating a vehicle for parking. <P>SOLUTION: An ECU of the parking assistance device reads a vehicle location coordinate detected by a GPS and a vehicle front-back azimuth detected by a geomagnetic sensor, and calculates an angle difference δ between a vehicle front-back direction and a vehicle traveling direction based on the vehicle location coordinate and the vehicle front-back azimuth. When an absolute value of the angle difference δ is larger than a predetermined differential threshold A<SB>2</SB>, the ECU turns a guide line display flag OFF. When the absolute value of the angle difference δ is the predetermined differential threshold A<SB>1</SB>or more and the predetermined differential threshold A<SB>2</SB>or less, the ECU turns the guide line display flag ON and turns a guide line correction flag ON. When the absolute value of the angle difference δ is smaller than the predetermined differential threshold A<SB>1</SB>, the ECU turns the guide line display flag ON and turns the guide line correction flag OFF. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a parking assist device that assists in parking a vehicle when the vehicle is parked backward.

  As a conventional parking assistance device, for example, as described in Patent Document 1, when a vehicle is parked in a parking frame from the rear, a steering angle of a steering is detected by a steering angle sensor, and based on the steering angle. It is known to calculate a predicted trajectory of a vehicle and display the predicted trajectory on a display device as a guide line.

JP 2008-49889 A

  When a vehicle is parked in a parking frame in a narrow space or in a parking frame in which other vehicles or buildings exist on the left and right sides, high prediction accuracy is required as a guide line displayed on the display device. However, when there is an angle difference between the vehicle front-rear direction and the vehicle traveling direction at the straight-ahead steering angle due to a change in rear wheel alignment, the generation of a rear wheel steering angle, etc., the guide line will be displayed deviated. . However, in the above prior art, no consideration is given to the deviation (error) of the guide line caused by the angle difference between the vehicle longitudinal direction and the vehicle traveling direction.

  The objective of this invention is providing the parking assistance apparatus which can perform suitable parking assistance, when reversing and parking a vehicle.

  The present invention relates to a parking assist apparatus for displaying a predicted parking locus line of a vehicle when the vehicle is parked while reversing the vehicle, an angle difference detecting means for detecting an angle difference between a front-rear direction of the vehicle and a traveling direction of the vehicle, and an angle And a display mode determining unit that determines a display mode of the parking prediction trajectory line based on an angle difference between the front-rear direction of the vehicle and the traveling direction of the vehicle detected by the difference detection unit.

  As described above, in the parking assist device of the present invention, when the vehicle is retracted and parked, an angular difference between the front-rear direction of the vehicle and the traveling direction of the vehicle is detected, and the parking prediction trajectory line is determined based on the angular difference. The display mode is determined. At this time, for example, when the angle difference between the vehicle front-rear direction and the vehicle traveling direction is large, by not displaying the parking prediction locus line, the driver is notified that the display error of the parking prediction locus line is large. When the angle difference is small, it is possible to improve the display accuracy of the predicted parking track line by correcting the display of the predicted parking track line. This makes it possible to perform appropriate parking assistance.

  Preferably, the display mode determining means determines to prohibit the display of the parking prediction trajectory line when the angle difference between the front-rear direction of the vehicle and the traveling direction of the vehicle is larger than the first predetermined value. In this case, since the parking prediction locus line is not displayed, erroneous parking guidance to the driver is prevented.

  At this time, when the angle difference between the front-rear direction of the vehicle and the traveling direction of the vehicle is larger than the second predetermined value and smaller than the first predetermined value, the display mode determining means It is preferable to determine to correct based on the above. In this case, since the display accuracy of the parking predicted locus line is increased, correct parking guidance can be performed for the driver.

  Preferably, the angle difference detection means is based on a geomagnetic sensor that detects the front-rear direction of the vehicle, a GPS receiver that detects the current position of the vehicle, the front-rear direction of the vehicle, and the current position of the vehicle. Means for calculating an angle difference between the front-rear direction and the traveling direction of the vehicle. In this case, the angular difference between the front-rear direction of the vehicle and the traveling direction of the vehicle can be detected without incurring high costs.

  The angle difference detection means calculates an angle difference between the vehicle front-rear direction and the vehicle traveling direction based on the ground vehicle speed sensor that detects the vehicle front-rear speed and the left-right speed, and the vehicle front-rear speed and the left-right speed. May have a means to do. In this case, the angle difference between the front-rear direction of the vehicle and the traveling direction of the vehicle can be detected using a simple calculation process.

  ADVANTAGE OF THE INVENTION According to this invention, when parking a vehicle backward, suitable parking assistance can be performed. As a result, the burden on the driver can be reduced.

It is a block diagram which shows schematic structure of one Embodiment of the parking assistance apparatus concerning this invention. It is a figure which shows a mode that a vehicle is reverse | retreated and it parks in a parking lot. It is a figure which shows the example of a display of the guide line in the back guide monitor shown in FIG. It is a figure which shows the relationship between a vehicle front-back direction and a vehicle advancing direction. It is a flowchart which shows the detail of the procedure of the guide line display setting process performed by the guide line display setting part shown in FIG. It is a figure which shows the difference in the driving | running | working locus | trajectory of a vehicle in case there exists a difference in the direction of a rear wheel, and the error of the guide line displayed on a back guide monitor. It is a block diagram which shows schematic structure of other embodiment of the parking assistance apparatus concerning this invention. It is a flowchart which shows the detail of the procedure of the guide line display setting process performed by the guide line display setting part shown in FIG. It is a figure which shows the relationship between vehicle front-rear speed and vehicle left-right speed, a vehicle front-back direction, and a vehicle advancing direction.

  Hereinafter, a preferred embodiment of a parking assistance apparatus according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a parking assistance apparatus according to the present invention. As shown in FIG. 2, the parking assist device 1 according to the present embodiment is a device that assists the parking of the vehicle A when the vehicle A is retracted and parked in the parking frame W in a parking lot or the like.

  In FIG. 1, a parking assist device 1 receives a vehicle speed sensor 2 that detects the speed of a vehicle, a steering angle sensor 3 that detects a steering angle of the vehicle, and a radio wave from a GPS (Global Positioning System) satellite. GPS receiver (hereinafter simply referred to as GPS) 4, a geomagnetic sensor 5 that detects the longitudinal direction of the vehicle, an ECU (Electronic Control Unit) 6, and a back guide monitor 7. And.

  As shown in FIG. 3, the back guide monitor 7 displays a line (guide line) G that guides a predicted trajectory that the vehicle is about to travel when the vehicle moves backward, and is provided for navigation, for example. . The travel locus of the vehicle forming the guide line G is obtained from the steering angle (front wheel turning angle) (see FIG. 2). As shown in FIG. 3, in addition to the guide line G, the back guide monitor 7 may also display a trajectory H when the vehicle travels straight forward.

  The ECU 6 includes a CPU, a memory such as a ROM and a RAM, an input / output circuit, and the like. The ECU 6 includes a guide line display setting unit 8 and a guide line display control unit 9.

  The guide line display setting unit 8 calculates an angle difference δ between the vehicle longitudinal direction P and the vehicle traveling direction Q as shown in FIG. 4 based on detection signals of the vehicle speed sensor 2, the steering angle sensor 3, the GPS 4, and the geomagnetic sensor 5. Based on the calculation result, whether to display the guide line G (see FIG. 3) on the back guide monitor 7 or whether to correct the display of the guide line G on the back guide monitor 7 is determined. The details of the procedure of the guide line display setting process executed by the guide line display setting unit 8 are shown in FIG.

  In FIG. 5, the straight travel continuation counter is first initialized to 0 (procedure S101), and the angle difference δ (see FIG. 4) between the vehicle longitudinal direction P and the vehicle traveling direction Q is initialized to 0 (procedure S102). Subsequently, the vehicle speed SPD detected by the vehicle speed sensor 2, the steering angle STR detected by the steering angle sensor 3, the vehicle position coordinates (longitude LNG, latitude LAT) detected by the GPS 4, and the geomagnetic sensor 5 The detected vehicle longitudinal direction AZM is read (step S103).

  Subsequently, it is determined whether or not the vehicle is running, that is, whether or not the vehicle speed SPD is equal to or higher than a predetermined speed threshold (step S104). When it is determined that the vehicle is in a traveling state, it is determined whether the vehicle is in a straight traveling state, that is, whether the absolute value of the steering steering angle STR is equal to or smaller than a predetermined steering angle threshold (step S105). When it is determined that the vehicle is in the straight traveling state, the straight traveling continuation counter is incremented (step S106).

  Subsequently, it is determined whether or not the straight travel continuation counter is 1 (procedure S107). If the straight travel continuation counter is 1, the vehicle initial position coordinates (longitude LNG_start, latitude LAT_start) are reset to 0 (procedure In step S108, the vehicle longitudinal direction integrated value sum_AZM is reset to 0 (step S109). Then, the vehicle position coordinates LNG and LAT read in step S103 are set as vehicle initial position coordinates LNG_start and LAT_start (step S110), and the vehicle longitudinal direction AZM read in step S103 is set as a vehicle longitudinal direction integrated value sum_AZM (step S111). . Thereafter, the process proceeds to step S120.

When it is determined in step S107 that the straight traveling continuation counter is not 1 (2 or more), the vehicle longitudinal direction integrated value sum_AZM is calculated by integrating the vehicle longitudinal direction AZM according to the following formula (step S112).
sum_AZM ← sum_AZM + AZM

Subsequently, it is determined whether or not the straight travel continuation counter is N (> 1) (procedure S113). When the straight travel continuation counter is N, the vehicle longitudinal average direction ave_AZM is estimated by the following equation (procedure S114). ).
ave_AZM ← sum_AZM / N

  Note that the vehicle longitudinal direction AZM is likely to fluctuate due to the crosswind received by the vehicle, the road surface cant, the steering wheel fine correction, and the like. Therefore, from the viewpoint of minimizing the influence of such fluctuations in the vehicle longitudinal direction AZM, the vehicle longitudinal average direction ave_AZM is estimated using the vehicle longitudinal direction integrated value sum_AZM.

Further, the vehicle traveling average direction ave_DIR is estimated by the following equation (step S115).
ave_DIR ← Tan ^-1 ((LAT-LAT_start) / (LNG-LNG_start))

Then, a difference value (current difference value) tmp_δ between the vehicle front-rear direction and the vehicle traveling direction at this time is calculated by the following equation (step S116).
tmp_δ ← ave_DIR−ave_AZM

Subsequently, a difference filter calculation is performed using the following equation (step S117). Here, the previous difference value δ and the current difference value tmp_δ are averaged to obtain a new difference value δ.
δ ← (δ + tmp_δ) / 2

  The reason why the difference filter calculation is performed is to reduce the influence of the change in the vehicle posture due to the wind, the road surface cant, and the like as described above. The difference filter calculation method is not particularly limited to the above formula, and many past difference value data may be used.

  Subsequently, the straight running continuation counter is set to 0 (procedure S118), and then the process proceeds to procedure S120.

  If it is determined in step S104 that the vehicle is not in a traveling state, and it is determined in step S105 that the vehicle is not in a straight traveling state, it is determined whether or not the straight traveling continuation counter is not 0 (step S119). When it is determined that the straight travel continuation counter is not 0, the straight travel continuation counter is set to 0 (step S118), and the process proceeds to step S120. When it is determined that the straight travel continuation counter is 0, the process proceeds directly to step S120. Also, when it is determined in step S113 that the straight running continuation counter is not N, the process proceeds to step S120.

In Step S120, it determines whether the absolute value of the difference value δ is larger than a predetermined difference threshold A _2. When the absolute value of the difference value δ is determined to be greater than the predetermined difference threshold value A ₂ is a guide line display flag to OFF (Step S121), the flow returns to step S103.

When the absolute value of the difference value δ is not greater than the predetermined difference threshold value A ₂ turns ON the guide line display flag (Step S122). Subsequently, the absolute value of the difference value δ is not less the predetermined difference threshold A ₁ or more and determines whether a predetermined difference threshold A ₂ or less (Step S123). When the absolute value of the difference value δ is determined to be and and the predetermined difference threshold value A ₂ below the predetermined difference threshold A ₁ or more, and a guide line correction flag to ON (Step S124), the flow returns to step S103. When the absolute value of the difference value δ is determined to be smaller than the predetermined difference threshold value A ₁ is a guide wire correction flag to OFF (Step S125), the flow returns to step S103.

  Returning to FIG. 1, the guide line display control unit 9 controls the display of the guide line G (see FIG. 3) on the back guide monitor 7 according to the result determined by the guide line display setting unit 8. Specifically, the guide line G is not displayed on the back guide monitor 7 when the guide line display flag is OFF.

  When the guide line display flag is ON and the guide line correction flag is OFF, the backward trajectory of the vehicle is predicted and calculated based on the steering steering angle (front wheel turning angle) detected by the steering angle sensor 3, and thereafter A guide line G corresponding to the retraction locus is displayed on the back guide monitor 7.

  When the guide line display flag is ON and the guide line correction flag is ON, the vehicle backward trajectory is predicted and calculated based on the steering angle detected by the steering angle sensor 3, and for example, a guide line display setting unit The backward trajectory is corrected based on the difference value δ obtained by 8, and a guide line G corresponding to the corrected backward trajectory is displayed on the back guide monitor 7.

  In the above, the procedures S101 to S119 in the guide line display setting unit 8 of the vehicle speed sensor 2, the steering angle sensor 3, the GPS 4, the geomagnetic sensor 5, and the ECU 6 detect an angle difference between the vehicle front-rear direction and the vehicle traveling direction. An angle difference detection means is comprised. The steps S120 to S125 in the guide line display setting unit 8 change the display mode of the predicted parking locus line (guide line) based on the angle difference between the vehicle front-rear direction and the vehicle traveling direction detected by the angle difference detection means. Display mode determining means for determining is configured.

  By the way, as shown in FIG. 6A, when a steering angle is generated in the rear wheel or the alignment of the rear wheel is changed, an angle difference δ between the vehicle longitudinal direction P and the vehicle traveling direction Q is generated. For this reason, even if the steering angle of the front wheels is the same, if there is a difference in the direction of the rear wheels, the traveling locus K of the vehicle will be different. In this case, as shown in FIG. 6B, an error (deviation) occurs in the guide line G displayed on the back guide monitor 7.

On the other hand, in the present embodiment, the current position coordinates of the vehicle are detected by the GPS 4 and the front-rear direction of the vehicle is detected by the geomagnetic sensor 5, and the vehicle front-rear direction and the vehicle are detected based on the current position coordinates and front-rear direction of these vehicles. An angle difference δ with respect to the traveling direction is obtained. Then, when the absolute value of the angle difference δ is larger than the predetermined difference threshold value A _2, since the non-display of the guide wire against the back guide monitor 7, it is possible to prevent performing parking guidance incorrect the driver . Further, when the absolute value of the angle difference δ is is and the predetermined difference threshold value A ₂ below the predetermined difference threshold A ₁ or more, since the display by correcting the guide line to the back guide monitor 7, the display of the guide lines Accuracy is ensured. Therefore, correct parking guidance can be performed for the driver.

  Accordingly, even when the vehicle is retracted and parked in a parking frame in a narrow space or in a parking frame in which other vehicles or buildings exist on both left and right sides, appropriate parking assistance can be implemented. As a result, it is possible to sufficiently reduce the burden on the driver.

  FIG. 7 is a block diagram showing a schematic configuration of another embodiment of the parking assistance apparatus according to the present invention. In the figure, the same or equivalent elements as those in the embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, the parking assist device 11 of the present embodiment includes a two-axis ground vehicle speed sensor 12 that collectively detects the longitudinal and lateral speeds of the vehicle, instead of the GPS 4 and the geomagnetic sensor 5 described above. Note that the front-rear speed and the left-right speed of the vehicle may be detected by separate ground vehicle speed sensors.

  FIG. 8 is a flowchart showing details of the procedure of the guide line display setting process executed by the guide line display setting unit 8 of the ECU 6 in the present embodiment. In FIG. 5, first, after steps S101 and S102 are executed as in FIG. 5, the vehicle speed SPD detected by the vehicle speed sensor 2, the steering steering angle STR detected by the steering angle sensor 3, and the biaxial ground vehicle speed. The vehicle longitudinal speed Vx and the vehicle lateral speed Vy (see FIG. 9) detected by the sensor 12 are read (step S131).

  Then, after executing steps S104 to S107 as in FIG. 5, the vehicle longitudinal speed integrated value sum_Vx and the vehicle lateral speed integrated value sum_Vy are reset to 0 (procedure S132). Then, the vehicle longitudinal speed Vx and the vehicle lateral speed Vy read in step S131 are set as the vehicle longitudinal speed integrated value sum_Vx and the vehicle lateral speed integrated value sum_Vy (procedure S133). Thereafter, the process proceeds to step S120.

When it is determined in step S107 that the straight traveling continuation counter is not 1 (2 or more), the vehicle longitudinal speed Vx is accumulated by the following formula to calculate the vehicle longitudinal speed integrated value sum_Vx, and the vehicle lateral speed Vy Are integrated to calculate a vehicle left-right speed integrated value sum_Vy (step S134).
sum_Vx ← sum_Vx + Vx
sum_Vy ← sum_Vy + Vy

Subsequently, as in FIG. 5, it is determined whether or not the straight travel continuation counter is N (> 1) (step S113). When the straight travel continuation counter is N, as shown in FIG. A difference value (current difference value) tmp_δ between the vehicle front-rear direction P and the vehicle traveling direction Q is calculated (step S135).
tmp_δ ← Tan ⁻¹ (sum_Vy / sum_Vx)

  Thereafter, steps S117 and S118 are executed in the same manner as in FIG. 5, and the procedure proceeds to step S120. And procedures S120-S125 are performed like FIG.

  In the above, the procedures S101 to S102, S104 to S107, S113, S117 to S119, and S131 to S135 in the vehicle speed sensor 2, the steering angle sensor 3, the biaxial ground speed sensor 12, and the guide line display setting unit 8 of the ECU 6 are as follows. An angle difference detecting means for detecting an angle difference between the front-rear direction of the vehicle and the traveling direction of the vehicle is configured.

  As described above, in the present embodiment, the vehicle longitudinal speed and the vehicle lateral speed are detected by the biaxial ground speed sensor 12, and the vehicle longitudinal direction and the vehicle traveling direction are determined based on the vehicle longitudinal speed and the vehicle lateral speed. Since the angle difference δ is obtained and display / non-display and correction / non-correction of the guide line with respect to the back guide monitor 7 are determined using the angle difference δ, the vehicle is moved backward and parked in the same manner as in the above-described embodiment. Appropriate parking assistance can be implemented.

  DESCRIPTION OF SYMBOLS 1 ... Parking assistance apparatus, 2 ... Vehicle speed sensor (angle difference detection means), 3 ... Steering angle sensor (angle difference detection means), 4 ... GPS receiver (angle difference detection means), 5 ... Geomagnetic sensor (angle difference detection means) ), 6... ECU, 7... Back guide monitor, 8... Guide line display setting unit (angle difference detecting means, display mode determining means), 9... Guide line display control unit, 11. Vehicle speed sensor (angle difference detection means).

Claims (5)

In the parking assistance device that displays the predicted parking locus line of the vehicle when the vehicle is retracted and parked,
Angle difference detection means for detecting an angle difference between the front-rear direction of the vehicle and the traveling direction of the vehicle;
And a display mode determining unit that determines a display mode of the predicted parking locus line based on an angular difference between the front-rear direction of the vehicle and the traveling direction of the vehicle detected by the angle difference detection unit. Parking assistance device.   The display mode determining means determines to prohibit the display of the parking prediction trajectory line when the angle difference between the front-rear direction of the vehicle and the traveling direction of the vehicle is larger than a first predetermined value. The parking support apparatus according to claim 1.   The display mode determining means displays the parking prediction trajectory line when the angular difference between the front-rear direction of the vehicle and the traveling direction of the vehicle is larger than a second predetermined value and smaller than the first predetermined value. The parking support apparatus according to claim 2, wherein the determination is made so as to correct based on the angle difference.   The angle difference detecting means is based on a geomagnetic sensor that detects the front-rear direction of the vehicle, a GPS receiver that detects the current position of the vehicle, the front-rear direction of the vehicle, and the current position of the vehicle. The parking assist device according to any one of claims 1 to 3, further comprising means for calculating an angle difference between a front-rear direction of the vehicle and a traveling direction of the vehicle. The angle difference detecting means includes an anti-ground vehicle speed sensor that detects a longitudinal speed and a lateral speed of the vehicle, and an angle between a longitudinal direction of the vehicle and a traveling direction of the vehicle based on the longitudinal speed and the lateral speed of the vehicle. The parking assist device according to claim 1, further comprising a means for calculating a difference.

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