JP2009294094A - System and method for detecting obstacle, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method for detecting an obstacle, and a computer program, which enable accurate detection of a relative position of the obstacle even in the case when the obstacle is detected from a moving mobile object. <P>SOLUTION: When a parking support processing program is implemented, an ultrasonic wave is transmitted from ranging sensors 5A and 5B to the lateral side of a vehicle 2, while a reflected wave from the obstacle is received after a prescribed time passes. A point P of reflection of the reflected wave received by the vehicle is calculated thereafter, based on a distance of movement of the vehicle from the position of transmission of the ultrasonic wave to the position of reception of the reflected wave, measured distance values of the ranging sensors 5A and 5B, etc., and the obstacle is detected from stroke data on the point P of reflection of the reflected wave. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an obstacle detection device, an obstacle detection method, and a computer program for detecting an obstacle.

  2. Description of the Related Art Conventionally, there is a parking assistance device that displays a camera image that captures the environment behind a vehicle during parking and assists a driver's parking operation with respect to the vehicle. In such a parking assistance device, the situation of the backward direction side with respect to the vehicle is displayed as an image to assist the driver's parking operation with respect to the vehicle, or the vehicle travels based on the signal from the steering angle sensor. There is known one that supports a driver's parking operation with respect to a vehicle by calculating a prediction curve and displaying the calculated progress prediction curve superimposed on the captured camera image as described above. Furthermore, the parking assist device not only simply displays an image of the rear environment, but also calculates the travel route of the vehicle until parking is completed in the target parking space, and the vehicle follows the calculated travel route. A technique for assisting steering so that the vehicle travels is known.

And in order to perform the above parking assistance appropriately, it is important to specify correctly the position and size of the parking space used as parking object. Here, conventionally, a method of detecting a parking space using a distance measuring sensor such as an ultrasonic sensor attached to the side of the vehicle is generally used (for example, JP-A-2004-85214). In such a distance measuring sensor, for example, an ultrasonic wave, a millimeter wave, or the like is transmitted, and the position of the obstacle with respect to the vehicle is detected based on a time interval until the reflected wave reflected by the obstacle is received.
JP 2004-85214 A (pages 4-7, FIG. 3, FIG. 4)

  However, the method for detecting a parking space by the distance measuring sensor described in Patent Document 1 does not consider the movement of the vehicle at the time of detection. That is, when the vehicle detects the parking space, the parking space is detected by the distance measuring sensor while traveling at a predetermined speed. Therefore, the vehicle position differs between the transmission position where the transmission wave is transmitted and the reception position where the reflected wave is received. In particular, when an ultrasonic sensor is used as a distance measuring sensor, the propagation speed of ultrasonic waves in the air is slower than that of electromagnetic waves, so that the vehicle position differs greatly. As a result, the following problems have occurred.

  In FIG. 8, as an example of the detection of the parking space by the parking execution vehicle, a case where an obstacle that forms a parking space in the parking lot or on the side of the road is detected by the distance measuring sensor 102 as the parking execution vehicle 101 moves. Show. FIG. 8 shows the transmission position of the transmission wave and the reception position of the reflected wave of the vehicle 101, respectively. Here, the parameter that can be detected by the distance measuring sensor 102 is the distance R (= the reception position) from the position A of the distance measuring sensor 102 of the vehicle 101 at the transmission position to the reflection point B where the reflected wave received is reflected. The distance to the reflection point B where the reflected wave received from the position C of the distance measuring sensor 102 of a certain vehicle is reflected. However, even if the distance from the position A of the distance measuring sensor 102 to the reflection point B can be detected, the reflection point B with respect to the vehicle 101 cannot be accurately specified.

This is because the position of the reflection point B with respect to the vehicle 101 is displaced by the vehicle speed of the vehicle 101. That is, when the vehicle speed is high, the difference between the reception position and the transmission position of the vehicle widens, so that the reflection point B moves further in the traveling direction of the vehicle. On the other hand, when the vehicle speed is low, the difference between the reception position and the transmission position of the vehicle is narrowed, and the reflection point B moves in the direction opposite to the traveling direction of the vehicle. In particular, when the vehicle is stopped, the reflection point B is the front position of the distance measuring sensor 102. Since the obstacle is detected based on the point sequence data of the reflection point B, if the position of the reflection point B cannot be accurately specified, the position of the obstacle, that is, the shape of the parking space is determined from the vehicle. There was a problem that could not be accurately identified.
The above problem is not limited to the case where the parking space is detected from the vehicle, but is a problem that generally occurs when an obstacle is detected from a moving moving object.

  The present invention has been made to solve the above-described conventional problems. For example, even when an obstacle is detected from a moving body such as a parking execution vehicle, the position of the obstacle is accurately detected. An object of the present invention is to provide an obstacle detection device, an obstacle detection method, and a computer program that can be performed.

In order to achieve the object, an obstacle detection apparatus (1) according to claim 1 of the present application receives a transmission means (3) for transmitting a transmission wave and a reflected wave that is the transmission wave reflected by the obstacle. An obstacle position detection means (3) for detecting the position of the obstacle based on a reception means (3) and a transmission position of the mobile body that has transmitted the transmission wave and a reception position of the mobile body that has received the reflected wave It is characterized by having.
The “transmitted wave” corresponds to a sound wave such as an ultrasonic wave or an electromagnetic wave such as a millimeter wave.

  An obstacle detection device (1) according to claim 2 is the obstacle detection device according to claim 1, wherein the obstacle position detection means (3) moves from the transmission position to the reception position. A moving distance calculating means (3) for calculating a moving distance of the body, and a receiving section (5A) that receives the reflected wave at the position of the transmitting section (5A, 5B) that transmitted the transmitting wave at the transmitting position or the receiving position. , 5B), the reflection distance calculation means (3) for calculating the distance from the reflection point received by the reception position to the reflection point, the movement distance calculated by the movement distance calculation means, and the reflection distance calculation means Reflection position calculation means (3) for calculating the position of the reflection spot based on the distance to the reflection spot calculated by the above, and at a plurality of reflection spot positions calculated by the reflection position calculation means. Based on And detecting the position of the obstacle.

  The obstacle detection method according to claim 3 includes a transmission step (S11) for transmitting a transmission wave, a reception step (S14) for receiving a reflected wave that is the transmission wave reflected by the obstacle, and the transmission. An obstacle position detecting step (S4, S5, S17) for detecting the position of the obstacle based on the transmission position of the mobile body that has transmitted the wave and the reception position of the mobile body that has received the reflected wave. It is characterized by.

  A computer program according to claim 4 is installed in a computer and has a transmission function (S11) for transmitting a transmission wave, and a reception function (S14) for receiving a reflected wave that is the transmission wave reflected by an obstacle. An obstacle position detection function (S4, S5, S17) for detecting the position of the obstacle based on the transmission position of the mobile body that has transmitted the transmission wave and the reception position of the mobile body that has received the reflected wave; Is executed.

  According to the obstacle detection device according to claim 1 having the above-described configuration, it is possible to accurately detect the position of the obstacle even when the obstacle is detected from the moving body. As a result, for example, if the present invention is applied to a parking execution vehicle, the position and shape of the parking space can be accurately specified, and appropriate parking assistance can be performed.

  Further, according to the obstacle detection device of the second aspect, by taking into account the moving distance of the moving body from the timing of transmitting the transmission wave to the timing of receiving the reflected wave, the reflected wave received by the moving body The position of the reflection point can be specified accurately. As a result, the position of the obstacle can be accurately detected not only when the moving body is in the stopped state but also when the moving body is in the moving state.

  Further, according to the obstacle detection method of the third aspect, even when the obstacle is detected from the moving body, the position of the obstacle can be accurately detected. As a result, for example, if the present invention is applied to a parking space detection method for a parking execution vehicle, the position and shape of the parking space can be accurately specified, and appropriate parking assistance can be performed.

  Further, according to the computer program of the fourth aspect, even when an obstacle is detected from the moving body, the position of the obstacle can be accurately detected. As a result, for example, if the present invention is executed on a parking execution vehicle, the position and shape of the parking space can be accurately specified, and appropriate parking assistance can be performed.

  Hereinafter, an obstacle detection device according to an embodiment of the present invention will be described in detail with reference to the drawings based on an embodiment. First, a schematic configuration of the obstacle detection apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram of an obstacle detection apparatus 1 according to this embodiment, and FIG. 2 is a block diagram schematically showing a control system of the obstacle detection apparatus 1 according to this embodiment.

As shown in FIGS. 1 and 2, the obstacle detection apparatus 1 according to the present embodiment includes a parking assistance ECU (transmission means, reception means, obstacle position detection means, movement distance calculation means) installed on the vehicle 2. , Reflection distance calculation means, reflection position calculation means) 3, rear camera 4, distance measuring sensors (transmission unit, reception unit) 5A, 5B, liquid crystal display 6, speaker 7, vehicle DB 8, and parking assist ECU 3 It is comprised by various sensors, such as GPS10, the vehicle speed sensor 11, the steering sensor 12, the gyro sensor 13, and the shift lever sensor 14 which were connected to.
The distance measuring sensors 5A and 5B include an ultrasonic sensor using a sound wave such as an ultrasonic wave and a millimeter wave sensor using an electromagnetic wave such as a millimeter wave. In the following embodiments, the ultrasonic sensor is used as the distance measuring sensor 5A. , 5B will be described as an example.

  When parking the vehicle 2 in the parking space, the parking assist ECU (Electronic Control Unit) 3 detects the relative position of the obstacle that forms the parking space with respect to the vehicle 2 using the distance measuring sensors 5A and 5B. Thus, the electronic control unit performs the parking support process (see FIGS. 3 to 5) and the like that identify the shape of the parking space and assist the parking of the parking space whose shape is specified. The parking assist ECU 3 may also be used as an ECU used for controlling the navigation device. The detailed configuration of the parking assist ECU 3 will be described later.

  The rear camera 4 uses a solid-state image sensor such as a CCD, for example, and is installed near the upper center of the license plate mounted on the rear side of the vehicle 2 and installed with the line of sight 45 degrees below the horizontal. The Then, the rear side of the vehicle that is the traveling direction of the vehicle 2 is imaged when the vehicle is moving backward, and the captured image is displayed on the liquid crystal display 6.

  The distance measuring sensors 5A and 5B are installed in a pair of left and right in front of the vehicle 2, and basically include a sound wave transmitting unit and a sound wave receiving unit. Then, an ultrasonic wave is emitted from the sound wave transmitting unit in the left-right direction of the vehicle 2 in the form of a pulse wave, and a reflected wave reflected by an obstacle (specifically, a parked vehicle, a block fence, etc.) is received by the sound wave receiving unit. Receive. As a result, the parking assist ECU 3 can detect the distance to the obstacle located around the vehicle 2 based on the time from the reception of the ultrasonic wave to the reception of the reflected wave. The parking assist ECU 3 in the present embodiment further specifies the detection of the parking space located around the vehicle, the shape of the detected parking space, and the like based on the detection results of the distance measuring sensors 5A and 5B.

  The liquid crystal display 6 is provided on the center console or panel surface of the vehicle 2 and displays the predicted course trajectory of the host vehicle superimposed on the vehicle rear image captured by the rear camera 4 during execution of the parking support process. (So-called back guide monitor). The liquid crystal display 6 may also be used as a navigation device.

  The speaker 7 is provided on the center console or the panel surface in the room of the vehicle 2 and outputs a guidance voice, a warning sound, etc. regarding driving support.

The vehicle DB 8 is a storage unit that stores various parameter information related to the vehicle such as the shape design value of the vehicle 2 and the camera design value. For example, in the vehicle DB 8, the wheel radius of the vehicle 2, the vehicle length, the vehicle width, the vehicle height, the wheel base, the minimum turning radius, the optical axis direction of the rear camera 4, the rear camera 4 with respect to the vehicle 2, and the distance measuring sensors 5 </ b> A and 5 </ b> B. The installation position and the like are stored.
And parking assistance ECU3 calculates the parking route to a parking space by the parking assistance process (refer FIGS. 3-5) mentioned later by using the various parameter information memorize | stored in vehicle DB8 so that it may mention later. Similarly, parking assistance of the vehicle 2 based on the calculated parking route is performed by using various parameter information stored in the vehicle DB 8.

  The GPS 10 can detect the current location and the current time of the vehicle by receiving radio waves generated by an artificial satellite.

  The vehicle speed sensor 11 is a sensor for detecting a moving distance and a vehicle speed of the vehicle, generates a pulse according to the rotation of the wheel of the vehicle 2, and outputs a pulse signal to the parking assist ECU 3. And parking assistance ECU3 calculates the rotational speed and moving distance of a wheel by counting the generated pulse.

The steering sensor 12 is a sensor that is attached to the inside of the steering device and that can detect the turning angle of the steering.
The gyro sensor 13 is a sensor that can detect the turning angle of the vehicle 2. Further, by integrating the turning angle detected by the gyro sensor 13, the vehicle direction can be detected.
The shift lever sensor 14 is built in a shift lever (not shown), and the shift position is “P (parking)”, “N (neutral)”, “R (reverse)”, “D (drive)”, “2”. It is possible to detect which position is (second) or “L (low)”.

  Next, the details of the parking assistance ECU 3 will be described with reference to FIG. 2. The parking assistance ECU 3 is configured with the CPU 21 as a core, and a ROM 22 and a RAM 23 which are storage means are connected to the CPU 21. The ROM 22 stores various programs necessary for control of the rear camera 4 and the distance measuring sensors 5A and 5B, a parking assistance processing program (FIGS. 3 to 5) described later, and the like. The RAM 23 is a memory for temporarily storing various data calculated by the CPU 21.

  Next, a parking assistance processing program executed by the parking assistance ECU 3 of the obstacle detection apparatus 1 according to this embodiment having the above-described configuration will be described with reference to FIG. FIG. 3 is a flowchart of the parking support processing program in the obstacle detection apparatus 1 according to the present embodiment. Here, the parking support processing program is executed when a predetermined operation is performed by the user, calculates a parking route for allowing the vehicle to enter the detected parking space, and parks the vehicle based on the calculated parking route. It is a program that provides support. The programs shown in the flowcharts of FIGS. 3 to 5 below are stored in the ROM 22 and the RAM 23 provided in the parking assist ECU 3 and are executed by the CPU 21. In the embodiment described below, parking assistance in the case of performing parallel parking will be described.

  First, in step (hereinafter abbreviated as S) 1 in the parking assistance processing program, the CPU 21 performs an initialization process. In this initialization process, the wheel speed pulse count is initialized, and the current vehicle position and direction are set as the vehicle reference position and reference direction in the subsequent parking assistance process. Specifically, the current vehicle position is set as the origin, the vehicle body centerline traveling direction is set as the Y axis, the direction passing through the origin and perpendicular to the Y axis is set as the X axis, and the subsequent vehicle position is its coordinates. The system is configured to be specified (see FIG. 7). The position coordinates of the own vehicle are specified by the coordinates of the center point of the rear wheel axis of the own vehicle.

  Next, in S2, the CPU 21 starts measuring the timer. The timer value is used when calculating the vehicle speed or when calculating the distance values by the distance sensors 5A and 5B.

  Subsequently, in S3, the CPU 21 performs a distance measurement process (FIG. 4) described later. In the distance measurement processing, vehicle information at the timing at which the ultrasonic waves are transmitted by the distance measuring sensors 5A and 5B and vehicle information at the timing at which the transmitted ultrasonic waves are reflected by the obstacle are respectively acquired. This is a process of storing together with the distance measurement value.

  Here, the sub-process of the ranging process executed by the parking assist ECU 3 in S3 will be described with reference to FIGS. FIG. 4 is a flowchart of a sub-processing program for distance measurement processing according to this embodiment. FIG. 6 is a diagram illustrating an example of a parking execution vehicle that executes a parking space detection process.

  First, in S11, the CPU 21 transmits ultrasonic waves from the distance measuring sensors 5A and 5B to the side of the vehicle. Note that S11 corresponds to the processing of the transmission means.

Subsequently, in S12, the CPU 21 acquires various types of vehicle information at the timing at which the ultrasonic waves are transmitted. Specifically, the vehicle information acquired in S12 includes the wheel speed pulse count c1, the current vehicle position coordinates (x1, y1), the steering angle φ1, and the like.
The wheel speed pulse count c1 is counted based on the pulse signal transmitted from the vehicle speed sensor 11.
The current position coordinates (x1, y1) of the host vehicle are specified by a coordinate system in which the host vehicle position detected in S1 is the origin and the vehicle body centerline traveling direction is set to the Y axis. In the initial process, the vehicle speed sensor 11 and the gyro sensor 13 detect the moving distance from the reference position (origin) set in S1 and the turning angle from the reference azimuth (Y axis), so that the position coordinates of the host vehicle are detected. To get. Thereafter, the current vehicle position coordinates in the coordinate system are acquired by detecting the movement distance from the vehicle position at the time when the process of acquiring the previous vehicle position coordinates is performed by the vehicle speed sensor 11. Further, the current vehicle direction in the coordinate system is acquired by detecting the turning angle from the vehicle direction at the time of performing the process of acquiring the previous vehicle direction by the gyro sensor 13.
Further, the steering angle φ1 is acquired based on the detection result of the steering sensor 12.

  Next, in S13, the CPU 21 acquires the count value t1 of the timer at the timing when the ultrasonic wave is transmitted.

  Thereafter, in S14, the CPU 21 receives a reflected wave in which the ultrasonic wave transmitted in S11 is reflected by an obstacle. If the reflected wave cannot be received within a predetermined time after transmitting the ultrasonic wave (for example, until the next ultrasonic wave transmission timing), it is determined that the obstacle has not been detected. Further, S14 corresponds to the processing of the receiving means.

  Subsequently, in S15, the CPU 21 acquires various vehicle information at the timing when the reflected wave is received. Specifically, the vehicle information acquired in S15 includes wheel speed pulse count c2, current vehicle position coordinates (x2, y2), steering angle φ2, and the like. Note that the current position coordinates (x2, y2) of the own vehicle are the moving speed and traveling direction from the own vehicle position coordinates (x1, y1) at the time of performing the processing of S12. It is acquired by detecting with the gyro sensor 13 or the like.

  Next, in S16, the CPU 21 obtains the count value t2 of the timer at the timing when the reflected wave is received.

Thereafter, in S17, the CPU 21 calculates a distance measurement value based on a time interval from transmission of the ultrasonic wave to reception of the reflected wave reflected by the obstacle, and the calculated distance measurement value is calculated in S12, S13, S15. , Stored in association with various information acquired in S16. Thereafter, the process proceeds to S4.
In the present embodiment, the distance values calculated by the distance sensors 5A and 5B are the reflections of reflected waves reflected from the sensor position S of the vehicle 2 located at the transmission position where the ultrasonic waves are transmitted as shown in FIG. A distance L to the point P (= a distance from the sensor position S ′ of the vehicle 2 located at the reception position where the reflected wave is received to the reflected point P where the reflected wave is reflected). The distance L is calculated by the following equation (1).
L = V (t2-t1) / 2 (1)
(V: speed of sound)
Note that S17 corresponds to the processing of the reflection distance calculation means.

  Next, in S4, the CPU 21 performs a reflection position calculation process (FIG. 5) described later. The reflection position calculation process is a process for calculating the reflection point of the received reflected wave based on the information acquired in the distance measurement process of S3.

  Here, the reflection position calculation process executed by the parking assist ECU 3 in S4 will be described with reference to FIGS. FIG. 5 is a flowchart of a sub-processing program for reflection position calculation processing according to the present embodiment. In the embodiment described below, it is assumed that the steering angle of the vehicle during distance measurement is always turning at 0 ° or a negligibly small angle in order to simplify the calculation formula.

First, in S21, the CPU 21 calculates the vehicle speed v of the own vehicle during the distance measurement. Specifically, it is calculated by the following equation (2).
v = k (c2-c1) / (t2-t1) (2)
(K: a coefficient for converting the pulse count value into the moving distance of the vehicle, which is the moving distance of the vehicle per pulse)

Next, in S22, the CPU 21 calculates a moving distance Δy of the own vehicle during the distance measurement. Specifically, it is calculated by the following equation (3).
Δy = v × (t2−t1) (3)
(V: Vehicle speed of the vehicle during distance measurement calculated in S21)
Note that S22 corresponds to the processing of the movement distance calculation means.

Next, in S23, the CPU 21 calculates the coordinates (x3, y3) of the position S ′ of the distance measuring sensor of the own vehicle at the reception position. Specifically, it is calculated based on the position coordinates (x2, y2) of the host vehicle at the reception position and the parameters stored in the vehicle DB 8.
It should be noted that the coordinates (x3, y3) of the position sensor S 'of the vehicle's distance measuring sensor at the reception position correspond to the “position of the reception unit that receives the reflected wave at the reception position” of the present invention.
Further, the coordinates of the position S of the distance measuring sensor of the own vehicle at the transmission position correspond to “the position of the transmission unit that transmitted the transmission wave at the transmission position” in the present invention.

Subsequently, in S24, the CPU 21 calculates the coordinates (x4, y4) of the reflection point P where the reflected wave received in S14 is reflected. Specifically, it is calculated by the following formulas (4) to (7).
L ′ = L × cos θ (4)
θ = arcsin ((Δy / 2) / L) (5)
x4 = x3-L ′ (6)
y4 = y3-Δy / 2 (7)
(L ′: distance from S ″ to P, which is an intermediate point between S and S ′)
Note that the calculation formulas (4) to (7) for the coordinates (x4, y4) of the point P are calculation formulas when it is assumed that the host vehicle has moved parallel to the parking space. The time interval from transmission of the transmission wave by 5A, 5B to reception of the reflected wave is very short. Therefore, when the vehicle moves in an oblique direction with respect to the parking space, the error can be ignored even if the coordinates (x4, y4) of the point P are calculated using the calculation formulas (4) to (7). Small enough. That is, there is no problem if the coordinates (x4, y4) of the point P are calculated using the calculation formulas (4) to (7) when the own vehicle moves in an oblique direction with respect to the parking space.
However, the traveling direction angle of the host vehicle with respect to the parking space may be detected, and the coordinates (x4, y4) of the point P may be calculated using the traveling direction angle.
Also, assuming that the coordinates of the position sensor S of the vehicle at the transmission position are (x5, y5), equations (6) and (7) are replaced by the following equations (6-1) and (7-1). It is also possible.
x4 = x5-L ′ (6-1)
y4 = y5 + Δy / 2 (7-1)
Note that S24 corresponds to the processing of the reflection position calculation means.

  In S25, the CPU 21 stores the coordinates (x4, y4) of the reflection point P calculated in S24 in the RAM 23 or the like as point sequence data. Thereafter, the process proceeds to S5.

  In S5, the CPU 21 detects an obstacle from the point sequence data of the reflection point P calculated in S4. Specifically, the end point of the obstacle is obtained from the inclination of the plurality of point sequences, the change rate of the inclination, etc., and the position and shape of the obstacle are specified.

  Further, in S6, the CPU 21 detects a parking space based on the obstacle detected in S5. Specifically, an empty space surrounded by an obstacle is recognized as a parking space, and the shape and position of the parking space are specified.

  Hereinafter, the obstacle and parking space detection processing in S5 and S6 will be described more specifically with reference to FIG. Here, FIG. 7 is an overhead view of the vicinity of the vehicle 2 when performing parallel parking in the parking space 33 surrounded by the other vehicle 31 and the guard rail 32 in the roadside belt.

As shown in FIG. 7, first in S5, as the vehicle 21 moves, the CPU 21 detects obstacles that form a parking space 33 in the parking lot or on the side of the road with the distance measuring sensors 5A and 5B (in FIG. 7, the other vehicle 31 and the guardrail). 32) detect the relative position. The relative position of the obstacle is specified by the point sequence data 34 of the reflection point P where the reflected wave calculated in S24 is reflected.
Next, in S6, the CPU 21 detects the parking space 33 formed by the detected obstacle. For example, in FIG. 7, the parking space 33 surrounded by the other vehicle 31 and the guard rail 32 is detected by the point sequence data 34 of the reflection point P. In the detection of the parking space 33, the shape and position of the parking space 33 (that is, the position coordinates of the parking frame 35) are calculated. Thereby, the shape and position of a parking space are specified. In addition, said S4, S5, S17 is equivalent to the process of a parking space information acquisition means.

  Subsequently, in S7, the CPU 21 determines whether or not the parking space detected in S6 is suitable as a parking target for the own vehicle. For example, when the parking space has a width that is equal to or greater than the width of the vehicle and has a length that is equal to or longer than the vehicle length × 1.5, it is determined that the parking space is suitable as a parking target for the host vehicle.

  If it is determined as a result of the determination in S7 that the parking space detected in S6 is suitable for parking (S7: YES), the process proceeds to S8. On the other hand, when it is determined that the parking space detected in S6 is not suitable as a parking target for the own vehicle (S7: NO), the process returns to S3 and continues to detect the parking space.

  In S8, the CPU 21 calculates a parking route for parking the vehicle in the parking space detected in S6. And parking assistance is started according to the calculated parking route. Specifically, the parking route is displayed on the liquid crystal display 6, and the timing of turning the steering wheel is guided by voice. The parking assistance in S8 ends when the shift position is changed to “P”, when the ignition is turned off, or when a predetermined operation is performed by the user.

As described in detail above, in the obstacle detection device 1 according to the present embodiment, the obstacle detection method by the obstacle detection device 1, and the computer program executed by the obstacle detection device 1, a parking assistance processing program is executed. Then, ultrasonic waves are transmitted from the distance measuring sensors 5A and 5B to the side of the vehicle 2 (S11), and a reflected wave reflected by an obstacle is received after a predetermined time (S14). Thereafter, the reflection point P of the reflected wave received by the vehicle is calculated based on the moving distance of the vehicle from the transmission position of the ultrasonic wave to the reception position of the reflected wave, the distance values of the distance measuring sensors 5A and 5B, and the like (S24). Since the obstacle is detected from the point sequence data of the reflection point P of the reflected wave (S5), even when the obstacle is detected from the moving body such as the parking execution vehicle, the relative position of the obstacle is determined. It becomes possible to detect accurately.
And based on the detected obstacle, it becomes possible to pinpoint the position and shape of a parking space correctly, and appropriate parking assistance can be performed.
Moreover, the position of the reflection point of the reflected wave received by the vehicle 2 can be accurately specified by considering the moving distance of the vehicle 2 from the timing of transmitting the ultrasonic wave to the timing of receiving the reflected wave. As a result, the relative position of the obstacle can be accurately detected not only when the vehicle 2 is stopped but also when the vehicle 2 is moving.

Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.
For example, in this embodiment, parking spaces and obstacles are detected by using ultrasonic sensors as the distance measuring sensors 5A and 5B, but they may be detected by using a millimeter wave sensor using millimeter waves. good.

  Moreover, although the example which detects the parking space at the time of performing parallel parking was demonstrated in this embodiment, this invention is applicable also when performing parking (for example, parallel parking) other than parallel parking.

It is a schematic block diagram of the obstruction detection apparatus which concerns on this embodiment. It is a block diagram which shows typically the control system of the obstacle detection apparatus which concerns on this embodiment. It is a flowchart of the parking assistance guidance processing program which concerns on this embodiment. It is a flowchart of the sub process program of the distance measurement process which concerns on this embodiment. It is a flowchart of the sub process program of the reflection position calculation process which concerns on this embodiment. It is a figure explaining the obstacle detection method of the present invention. It is a bird's-eye view of the vehicle periphery in the case of carrying out parallel parking to the parking space enclosed by the other vehicle and guardrail in a roadside zone. It is a figure explaining the conventional obstacle detection method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Obstacle detection apparatus 2 Vehicle 3 Parking assistance ECU
5A, 5B Ranging sensor 21 CPU
22 RAM
23 ROM

Claims (4)

A transmission means for transmitting a transmission wave;
Receiving means for receiving a reflected wave that is the transmitted wave reflected by an obstacle;
An obstacle position detecting means for detecting a position of the obstacle based on a transmission position of the mobile body that has transmitted the transmission wave and a reception position of the mobile body that has received the reflected wave; Object detection device. The obstacle position detecting means includes
A moving distance calculating means for calculating a moving distance of the moving body from the transmitting position to the receiving position;
Reflection for calculating the distance from the position of the transmitter that transmitted the transmission wave at the transmission position or the position of the reception unit that received the reflected wave at the reception position to the reflection point where the reflected wave received at the reception position was reflected A distance calculating means;
Reflection position calculation means for calculating the position of the reflection point based on the movement distance calculated by the movement distance calculation means and the distance to the reflection point calculated by the reflection distance calculation means;
With
The obstacle detection apparatus according to claim 1, wherein the position of the obstacle is detected based on the positions of the plurality of reflection points calculated by the reflection position calculation unit. A transmission step of transmitting a transmission wave;
A receiving step of receiving a reflected wave that is the transmitted wave reflected by an obstacle;
An obstacle position detecting step for detecting the position of the obstacle based on a transmission position of the mobile body that has transmitted the transmission wave and a reception position of the mobile body that has received the reflected wave. Object detection method. On the computer,
A transmission function for transmitting a transmission wave;
A receiving function for receiving a reflected wave that is the transmitted wave reflected by an obstacle; and
An obstacle position detection function for detecting the position of the obstacle based on the transmission position of the mobile body that has transmitted the transmission wave and the reception position of the mobile body that has received the reflected wave;
A computer program for executing

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