JPH11334470A - Parking auxiliary device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain effective information on longitudinal parking or parking in the garage with a simple displaying method, by finding a traveling estimated locus of a vehicle on the basis of the steering angle from a steering sensor for detecting the steering angle and variably displaying it to a display according to the steering angle. SOLUTION: Signals from a CCD camera 17 for picking up an image of the rear part of a vehicle, a steering sensor 2 for detecting the steering angle, a shift lever reverse switch 3, a parking switch 4 for operating a parking assist function in parking, and light and left wheel speed sensors 5, 6 are input to a controller 16. The controller 16 displays an image of the rear part of the vehicle and a traveling estimated locus 2O on a display 13 on the basis of these signals. Moreover, an acoustic composite output is emitted from a speaker 8 by an acoustic composite circuit 7. On the display 13, any one of light, left or middle display markers 14 is turned on according to the steering state of a steering wheel, and the turning direction of the steering wheel and the rear image are displayed together.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parking assist device for assisting parking such as parallel parking or garage parking of a vehicle. More particularly, the present invention relates to a parking assist device for photographing a rear image with a camera and displaying the rear image on a monitor display in the vehicle. The present invention relates to a parking assist device that assists a parking operation.

[0002]

2. Description of the Related Art Conventionally, there has been known a method of assisting a beginner who is unfamiliar with parking such as parallel parking or garage parking during a parking operation. For example, in JP-A-7-17328, a CCD camera and a distance sensor for measuring a distance are provided around the vehicle body,
The surroundings of the vehicle are detected, and a surrounding image of the surroundings of the vehicle is displayed in a bird's-eye view on a display provided inside the vehicle to provide the driver with the surrounding situation.

In Japanese Patent Application Laid-Open No. 59-201082, a steering angle is detected by a steering sensor, a steering angle is calculated and output by a simple display. In the example shown, the distance to an obstacle (particularly, a car parked next to a parking space to be parked, etc.) is measured by a distance measuring sensor for object detection provided behind the vehicle, and the distance is measured. There has been known a method of detecting a turning start position based on the maximum steering angle in response to the notification and notifying the driver of the turning start position.

[0004]

However, the above-described conventional method is based on the premise that obstacles around the vehicle are detected using various sensing techniques.
The system for the processing becomes complicated. In addition, the method of measuring and notifying the distance to a nearby obstacle using a distance measurement sensor or the like can be used when there is no car parked next to the parking space or when a person or object suddenly jumps out. It is difficult and does not assist parking properly.

The present invention has been made in view of the above-mentioned problems, and aims to assist parking by a simple method and appropriately provide useful information for parallel parking, parking in a garage, and the like. Is a technical issue.

[0006]

The technical means taken to solve the above-mentioned problem is to provide a steering sensor for detecting a steering angle, obtain an expected running trajectory of the vehicle from the steering angle from the steering sensor, and run the vehicle. The expected trajectory is variably displayed on the display in accordance with the steering angle.

According to the above-mentioned technical means, the expected running trajectory of the vehicle is obtained from the steering angle from the steering sensor, and the expected running trajectory is variably displayed on the display in accordance with the steering angle. Since parking can be performed while always checking the predicted travel trajectory corresponding to the angle on the display, the predicted travel trajectory corresponding to the steering angle can be understood from the display. That is, useful information for parking such as parallel parking or garage parking is provided by a simple display method.

In this case, if the predicted traveling trajectory is displayed so as to be superimposed on the rear image from the camera, the predicted traveling trajectory based on the steering angle can be superimposed on the rear image to check the state. Since the predicted running trajectory of whether the vehicle passes through the position can be confirmed at the same time, the visibility at the time of the parking operation is improved, and appropriate assistance at the time of the parking operation becomes possible.

Further, a parking switch for assisting parking is provided, and the predicted travel trajectory is switched between a rear image from the camera and an image in which the predicted travel trajectory is superimposed on the rear image by operating the parking switch. Only when it is necessary at the time of the parking operation, it is possible to display the predicted traveling trajectory superimposed on the rear image.

[0010] The predicted running trajectory can be displayed by any one of a predicted track of the vehicle in which the passing point of the tire is known, a vehicle-wide band in which contact with the surroundings of the vehicle can be determined, and a ladder-like display capable of recognizing the distance. In addition, a sense of distance can be recognized at the time of parking operation, and visibility is improved.

If the display color of the predicted travel trajectory is changed according to the steering state in the expression method, it is possible to identify the neutral state of the steering by the display color.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram of the parking assist device 1. In this figure, a controller 16 for controlling the parking assist device 1 includes a CCD camera (hereinafter, referred to as a camera) 17 for photographing the rear of the vehicle, and a steering sensor for detecting a steering angle of a steering wheel (hereinafter, referred to as a steering) 21. 2. A shift lever reverse switch 3 for detecting a reverse (reverse) state of a shift lever of a transmission, a parking switch 4 for operating a parking assist function at the time of a parking operation, and a wheel speed sensor 5 for detecting left and right wheel speeds of driven wheels. , 6 are input, and based on these signals, the controller 16 can display an image behind the vehicle and a predicted travel trajectory 20 to be described later on the display 13. 7, a voice is output from the speaker 8 to the driver by the voice synthesis output. It has become the jar.

In the controller 16, C for controlling
PU 11, a graphics drawing circuit 12 for drawing graphics on the display 13, a superimposing circuit 9 for superimposing a graphics signal and a rear image from the camera 17, a synchronization signal is extracted from the camera image and sent to the graphics drawing circuit 12. Supply synchronization separation circuit 10,
An image recognition device 15 for detecting a parking section that receives a signal from the camera 17 and performs image recognition of the parking section is provided. The image recognition device 15 can be provided separately from the controller 16.

On the display 13, there is provided a steering angle state display (display marker) 14 whose lighting state changes depending on the steering angle state of the steering wheel. And
The direction to which the steering wheel 21 is steered can be recognized together with the rear image.

FIG. 2 is a mounting diagram when the parking assist device 1 is mounted on a vehicle. A camera 17 for imaging the rear is mounted near the upper center of the license plate at the rear of the vehicle, and is installed with the optical axis directed downward. Specifically, FIG.
As shown in the figure below, in the center behind the vehicle (approximately 30 degrees)
The camera itself is secured with a wide-angle lens to ensure a 140 degree field of view in the left and right directions, and can capture an area up to about 8 m behind.

A display 13 is provided on a panel surface of a center console in the cabin of the vehicle.
Above the glove box, a controller 16 is provided inside. Further, the parking switch 4 for issuing a request for assisting parking is provided near the center console which is easy for the driver to operate.

Here, regarding the steering sensor 2,
This will be described with reference to FIG. The steering sensor 2 is a commercially available one and detects the steering angle of the steering 21. This is the steering column shaft 23
A slit plate 2a is attached so as to rotate integrally with the photoreceptor, and two sets of photointerrupters 2c and 2b having a phase difference of 90 ° are attached. In this configuration, by turning on / off the phototransistor by passing or blocking light by rotating a plurality of slits provided on the disk plate 2a in a circumferential shape, two A-phase and B-phase signal pulses are generated. Output. This means that the phase B is delayed by 90 ° or advanced ahead of the phase A depending on the rotation direction of the steering 21. In this case, the steering angle is 1 ° / pulse. Used.

Next, the processing of the controller 16 will be described with reference to FIG. When the controller 16 is turned on (the accessory switch is turned on), the program shown in FIG. 5 is started.

In step S101, various initial values are set in a memory required for this processing. Then, step S10
At step 2, the state of the shift reverse switch 3 is checked, and if it is off (not reverse), the display on the display 13 is stopped at step S111 and the process returns to step S102.
On the other hand, when the shift reverse switch 3 is turned on (reverse lever state), step S103 is performed. In step S103, the display 13 is switched to the camera image mode so that the image behind the vehicle can be displayed as a raw image. That is, it is a normal back monitor camera.

Next, at step S104, the parking switch 4 for assisting parking during the parking operation is checked. Here, if the parking switch 4 is off (there is no parking assistance request), the graphic screen of the display 13 is cleared in step S112, and only the rear raw image is displayed on the display 13, and the process returns to step S102. . On the other hand, if the parking switch 4 is on (there is a request for parking assistance) in step S104, the process proceeds to step S105, where a predetermined audio signal is output to the audio synthesizing circuit 7 and audio is output from the speaker 8. . In other words, depending on the situation, "Parking assist. Adjust the trajectory to the desired position and back while paying attention to the surroundings.", "The parking guide will start now. Turn the steering wheel so that the tip of the (track) display points toward the parking space. "," Be careful on the right (left). " Give guidance.

Next, in step S106, a steering sensor value N is read from the steering sensor 2, and
The current turning radius R at the time of the parking operation is calculated based on the value. Specifically, the reading of the steering sensor 2 is A
When the rising edge of the phase signal is detected, an interrupt is generated in the main program, and the interrupt processing shown in FIG. 6 is executed. That is, the state of the B-phase signal is checked in step S201 of FIG. 6, and if the B-phase signal is high (H: high potential), the steering count value N is incremented in step S202, and if low (L: low potential), it is decremented. Then, the value is stored in the memory. In this case, since one pulse is 1 °, the steering count value N is θ =
N.

However, since the absolute steering angle of the steering wheel 21 becomes unstable only by counting the steering value N shown above, the neutral point of the steering angle is detected by the method shown in FIG. Score points.

The determination of the neutral point will now be described with reference to FIG. This process is executed by a timer interrupt having a one-second cycle. Here, the vehicle speed is also normally calculated from signals from the known left and right wheel speed sensors 5 and 6 provided on the wheels. Step S301, step S30
In 2, the signals (pulses) from the left and right wheel speed sensors 5, 6
Is counted by a hardware counter built in the CPU 11 in the controller, the left and right wheel speeds are read out in this timer interrupt routine, and are stored in NR and NL of a memory in which wheel speed sensor values are stored. After reading, the counter itself is cleared, and NR and NL indicate the number of pulses per second.

In the next step S303, the average value (NR + NL) / 2 is calculated from NR and NL, and this value is multiplied by the circumference of the tire, so that the vehicle speed V can be easily obtained by a known method. Next, regarding the reference setting of the steering sensor 2, in steps S304 to S306, when the vehicle speed is equal to or higher than the predetermined speed (10 km / h), the vehicle is driven in a state where there is almost no pulse difference between the left and right wheel speed sensors 5 and 6. Assuming that the vehicle is in the straight traveling state, the steering counter N is reset to zero in step S306, and the neutral point of the steering angle is obtained.

On the other hand, in the main routine shown in FIG. 5, in step S107, the parameters of the predicted traveling trajectory 20 are calculated, and in step S108, the predicted traveling trajectory 20 obtained by a method described later is graphically drawn on the display 13 so as to overlap the rear image. . In step S109, the parking switch 4 is checked again. If the parking switch 4 is off (no parking assistance request), the process returns to step S102 and the same processing from step S102 is repeated, but on (the parking assistance request is present). In step S110, the shift reverse switch 3
Is checked, and if it is not reverse (reverse), the process returns to step S102. If it is in the reverse state, the same processing from step S106 to step S110 is repeated. That is, if a request for assisting parking is issued by the parking switch 4, the predicted travel trajectory 20 is repeatedly calculated, and the predicted travel trajectory 20 is variably displayed on the rear screen according to the steering angle (see FIG. 13). .

Next, a method of obtaining the predicted traveling locus 20 will be described. This is because, as shown in FIG. 8, the turning center O at a low speed (here, 10 km / h or less) exists on the extension of the axle behind the vehicle, and the steering angle (steering angle) ) The turning radius R is derived from θ and the wheel base L by a relational expression of R = L / tan θ. Note that, in this case, when the steering angle θ is 0, the vehicle is traveling straight ahead, and R
= ∞.

FIG. 10 shows graphics display coordinates (x, y) on the camera, and FIG. 12 shows a method of coordinate conversion using the illustrated coordinate system. As shown in FIG. 11, the camera 17 is mounted at a height Hc above the road surface with the optical axis inclined downward by θ from the horizontal state.
The lens is configured to have a wide angle and a large depth of focus, and to render an image of a road surface on a CCD device. Therefore, the following mapping relationship is established between the road surface coordinate system (X, Z) and the coordinate system (x, y) on the display.

Specifically, (X, Y, Z): road surface coordinates,
(X, y): camera coordinates on the CCD element surface, f: lens focal length of the camera, (x ′, y ′, z ′): lens coordinates,
θ: Camera mounting angle, Hc: Mounting height from the road surface, x = fxx / z ′, y = fy ′ / z ′ (1) x ′ = X, y ′ = x Zsinθ + (Y−Hc) cosθ｝ (2) The relational expression z ′ = Zcosθ− (Y−Hc) sinθ (3) holds. Here, if it is limited to only the coordinates on the road surface, Y = 0, and if x and y are obtained by the above relational expression, x = f × X / (Zcos θ + Hc × sin θ) (4) y = f (Zsin θ + Hc · cos θ) / (Zcos θ + Hc · sin θ) (5) That is, when the point (X, Z) on the road surface is photographed by the camera 17, the coordinates (x, y) on the graphics screen on the display can be obtained from the relational expressions of (4) and (5). it can.

When the (x, y) predicted travel locus 20 obtained by the above method is displayed on the display, various display methods are conceivable as shown in FIG. In other words, (a) shows a method of displaying the predicted track through which the left and right wheels of the vehicle pass, (b) shows a vector of the traveling area where the vehicle travels during parking, and (3) shows a constant distance interval (ladder interval: 50 cm). ) Can be displayed in a ladder-like manner so that the user can easily understand the sense of distance and the angle of the vehicle body at each position during the parking operation using (c). In this case, the length l of the predicted vehicle trajectory 20 is set to a fixed length (for example, 3 m) or a fixed angle, and the color is changed between a turning state (green) and a straight traveling state (blue). Alternatively, it is also possible to adopt a method in which only the leading end of the expected trajectory is displayed so that it can be easily distinguished.

FIG. 13 shows an example of a display screen on the display 13, showing a state in which the predicted running trajectory changes according to the steering angle. The parking switch 4 is turned on in an actual image behind the vehicle. Only when the vehicle is in the parking state (in a state where a parking assistance request is present), the ladder-like scheduled traveling trajectories 20 are displayed in an overlapping manner according to the steering angle. In this case, by displaying the predicted traveling trajectory in the rear image, a display marker 14 for displaying the steering angle state is displayed together with a part of the display 13 so that the user can know how much the steering angle is being turned. You can tell how much you actually steer.

In the parking assist device 1 according to the present invention, since the predicted traveling locus 20 is displayed in the rear image, the driver may steer the steering wheel 21 while visually observing the display 13 or the rear, hold the vehicle at an appropriate position, and back the vehicle. . After that, when the vehicle enters the parking space of the parking space horizontally, the steering is straightened, and if the vehicle is backed up to the rear end, the vehicle can enter the parking space properly, and can provide appropriate assistance during the parking operation.

[0033]

According to the present invention, the expected travel trajectory of the vehicle is obtained from the steering angle from the steering sensor, and the expected travel trajectory is variably displayed on the display according to the steering angle. Parking can be performed while always checking the predicted traveling locus corresponding to the vehicle on the display, so that the predicted traveling locus corresponding to the steering angle can be understood from the display. That is, useful information can be provided for parking such as parallel parking or garage parking by a simple display method.

In this case, if the predicted travel trajectory is displayed so as to be superimposed on the rear image from the camera, the state can be confirmed by superimposing the predicted travel trajectory based on the steering angle on the rear image. Since the predicted travel trajectory such as whether to pass through the position can be confirmed at the same time, the visibility at the time of the parking operation is improved, and appropriate assistance at the time of the parking operation can be performed.

Further, a parking switch for assisting parking is provided, and the predicted travel trajectory is switched between a rear image from the camera and an image in which the predicted travel trajectory is displayed on the rear image by superimposing the switch on the parking switch. Only when necessary at the time of the parking operation, the predicted running trajectory can be displayed superimposed on the rear image.

If the predicted traveling trajectory is displayed by any one of a predicted rut of a vehicle, a vehicle-like band, and a ladder-like display capable of recognizing a distance, the visibility such as a sense of distance can be improved during a parking operation. I do.

If the display color of the predicted traveling trajectory is changed according to the steering state, the steering state of the steering can be known from the display color.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a parking assist device according to an embodiment of the present invention.

FIG. 2 is a mounting diagram when the parking assist device according to the embodiment of the present invention is mounted on a vehicle.

FIG. 3 is a diagram illustrating a detection range of a camera according to an embodiment of the present invention.

4A and 4B show a steering sensor according to an embodiment of the present invention, wherein FIG. 4A is a plan view of the steering sensor when attached to a steering column shaft, and FIG. 4B shows an outline of a slit plate and a photo interrupter of the steering sensor. FIG. 3C is a diagram showing the outputs of the A and B phases of the steering sensor.

FIG. 5 is a flowchart illustrating processing of a controller according to the embodiment of the present invention.

FIG. 6 is a flowchart illustrating steering sensor signal processing of a controller according to an embodiment of the present invention.

FIG. 7 is a flowchart illustrating a neutral point process of the steering sensor of the controller according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram used for calculating a predicted traveling trajectory according to an embodiment of the present invention.

FIG. 9 is a diagram showing a display example of a predicted traveling trajectory according to an embodiment of the present invention, wherein (a) shows a display based on a predicted rut;
(B) is a diagram showing a running area belt display for the vehicle width, and (c) is a diagram showing a ladder-like display.

FIG. 10 shows graphics display coordinates of a camera and a display according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating an attached state when the camera of the parking assist device according to the embodiment of the present invention is attached to a vehicle.

FIG. 12 is an explanatory diagram illustrating a coordinate conversion method of the parking assist device according to the embodiment of the present invention.

FIG. 13 is a display screen example of a display according to the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 parking assist device 2 steering sensor 3 shift lever reverse switch 4 parking switch 5 right wheel speed sensor 6 left wheel speed sensor 13 display (display) 14 steering angle state display (marker display) 17 CCD camera (camera) 20 expected travel path

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryo Inoue 2-3-3 Showa-cho, Kariya-shi, Aichi Prefecture Inside Aisin New Hard Co., Ltd.

Claims (5)

[Claims] 1. A parking assist device for detecting the rear of a vehicle by a camera, displaying an image from the camera as a rear image on a display provided in the vehicle, and assisting a driver in a parking operation. A parking sensor for detecting an angle of the vehicle, obtaining a predicted travel trajectory of the vehicle based on a steering angle from the steering sensor, and variably displaying the predicted travel trajectory on the display according to a steering angle. apparatus. 2. The parking assist device according to claim 1, wherein the predicted travel locus is displayed so as to be superimposed on a rear image from the camera. 3. A parking switch for assisting parking is provided, and the predicted trajectory is switched between a rear image from the camera and an image in which the predicted trajectory is superimposed on the rear image by operating the parking switch. The parking assist device according to claim 2. 4. The parking assist device according to claim 3, wherein the predicted traveling trajectory is displayed by one of a predicted rut of a vehicle, a vehicle-shaped band, and a ladder-like display capable of recognizing a distance. 5. The parking assist device according to claim 4, wherein the predicted traveling trajectory changes a display color according to a steering state.