JP4914787B2 - Vehicle object detection device - Google Patents

Description

  The present invention relates to a vehicle object detection device.

Conventionally, for example, when the relative speed is obtained from the distance between the preceding vehicle and the own vehicle detected by the radar device, and the vehicle speed of the own vehicle is controlled so as to maintain the predetermined distance from the preceding vehicle, the following distance There is known an inter-vehicle distance control device (see, for example, Patent Document 1) that changes a time constant of a filter process that reduces an error in relative speed due to a variation (that is, a detection error) in accordance with an inter-vehicle distance and a vehicle speed.
In this inter-vehicle distance control device, for example, when the inter-vehicle distance is small or the vehicle speed is high, the time constant is reduced to improve control responsiveness.For example, when the inter-vehicle distance is large or the vehicle speed is low, the time constant is increased. It is designed to improve control stability.
JP-A-6-40270

By the way, in the inter-vehicle distance control device according to the above prior art, the time constant of the filter processing for reducing the error of the relative speed due to the variation in the inter-vehicle distance with respect to the preceding vehicle is changed, but the contact with the objects around the own vehicle In the control for avoiding the above, it is desired to reduce the error of the relative velocity accompanying the variation in the position of the object detected by the radar device or the like.
For example, when the shape of the electromagnetic wave scanned in the horizontal direction is substantially fan-shaped, the detection accuracy of the lateral position of the object (that is, the position in the direction crossing the traveling direction of the host vehicle) decreases as the distance increases. become. And when performing the filter process which reduces the dispersion | variation in this horizontal position, it is desired to prevent that the control which avoids a contact with a delay arises.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle object detection device capable of ensuring desired response while reducing an object position detection error.

In order to solve the above-described problems and achieve the object, the vehicle object detection device according to the first aspect of the present invention transmits an electromagnetic wave over a predetermined angle around the vehicle at a predetermined time interval. Transmitting and receiving means (for example, the radar device 15 in the embodiment) for receiving the reflected wave of the electromagnetic wave from an object existing in the vicinity, and a relative position and a relative distance between the own vehicle and the object based on the reflected wave Relative state quantity calculating means for calculating a relative state quantity (for example, a relative state quantity calculating unit 32 in the embodiment) and a relative for calculating a relative speed between the vehicle and the object based on the relative state quantity. Speed calculation means (for example, relative speed calculation section 33 in the embodiment), and relative speed correction means for correcting the relative speed by a predetermined filter time constant (for example, relative speed correction section 34 in the embodiment); The state of movement of the vehicle Travel locus prediction means for predicting a travel locus of the vehicle based on the vehicle (for example, the vehicle locus estimation section 31 in the embodiment), and the relative speed correction means is based on the distance of the object to the travel locus. The filter time constant is changed , and absolute position calculating means for calculating the absolute position of the object based on the movement state of the own vehicle and the relative position (for example, the absolute position calculating unit 36 in the embodiment). ) wherein the absolute position calculating means, when the change amount in the time series of the absolute position is less than the predetermined value, the absolute position of the lateral direction with respect to the vehicle traveling direction is recognized not changed.

Furthermore, in the vehicle object detection device according to the second aspect of the present invention, the absolute position calculation means sets the predetermined value based on the relative distance.

Furthermore, in the vehicle object detecting device according to the third aspect of the present invention, the relative speed correction means, said relative distance, based on the distance of the object relative to the travel path, the equivalent relative vehicle The filter time constant is changed with respect to the object having the relative distance such that the filter time constant changes in an increasing tendency as the distance of the object with respect to the traveling locus of the host vehicle increases. .

According to the vehicle object detection device of the first aspect of the present invention, the filter time constant is changed based on the distance of the object with respect to the traveling locus of the own vehicle, so that it is relatively far from the traveling locus of the own vehicle. The position detection error can be appropriately reduced with respect to the object, and the object relatively close to the traveling locus of the own vehicle (for example, other vehicles crossing the traveling locus of the own vehicle). Can quickly detect the position.
Furthermore , when the amount of change in the absolute position in time series is less than a predetermined value, it is recognized that the absolute position in the lateral direction with respect to the traveling direction of the vehicle has not changed. Can be prevented.
According to the vehicle object detection device of the second aspect of the present invention, since the predetermined value is set according to the degree of the position detection error that changes according to the relative distance, the absolute position error due to the position detection error is calculated. Outage can be prevented more accurately.
According to the vehicle object detection device of the third aspect of the present invention, the filter time constant is changed on the basis of the distance and relative distance of the object with respect to the traveling locus of the own vehicle. For objects that are relatively distant from the position, the position detection error can be reduced appropriately, and for objects that are relatively close to the traveling locus of the host vehicle and the position of the host vehicle, Position detection can be performed quickly.

Hereinafter, a vehicle object detection device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, for example, the vehicle object detection device 10 according to the embodiment of the present invention includes a yaw rate sensor 11, a steering angle sensor 12, a vehicle speed sensor 13, a navigation device 14, a radar device 15, and a control. A device 16, a brake actuator 17, and an alarm device 18 are provided.

The yaw rate sensor 11 detects the yaw rate of the host vehicle, that is, the amount of change in the yaw angle, which is the rotation angle around the vertical axis of the center of gravity of the vehicle.
The steering angle sensor 12 detects an actual steering angle (steering angle) according to the steering angle of the host vehicle (for example, the direction and magnitude of the steering angle input by the driver).
The vehicle speed sensor 13 detects the speed (vehicle speed) of the host vehicle.
The navigation device 14 detects the current position of the host vehicle from a positioning signal received from, for example, an artificial satellite, a base station, or the like, or an autonomous navigation calculation process based on detection signals from the sensors 11 and 13, and Map matching is performed on predetermined road data based on the information, and the detection result of the current position is corrected. In addition, while controlling the map display on a monitor (not shown) with respect to the current position or appropriate position information input by an operator via various input devices (for example, a touch panel), Processing such as route search and route guidance is performed.

The radar device 15 transmits an electromagnetic wave such as a laser beam or a millimeter wave toward a detection area ahead of the traveling direction of the own vehicle, and the transmitted electromagnetic wave is reflected by an object existing in the detection area. A beam scan radar 21 that receives the generated reflected wave and a control unit 22 that generates a beat signal by mixing the transmitted electromagnetic wave and the received electromagnetic wave (reflected wave) are provided.
The detection area of the radar apparatus 15 is divided into a plurality of scanning areas set with respect to the three-dimensional angular direction, and the radar apparatus 15 scans the detection area divided into the plurality of scanning areas.

  For example, the control device 16 includes a host vehicle trajectory estimation unit 31, a relative state quantity calculation unit 32, a relative speed calculation unit 33, a relative speed correction unit 34, an object distance calculation unit 35, and an absolute position calculation unit 36. The absolute position storage unit 37 and the vehicle control unit 38 are provided.

  The own vehicle trajectory estimation unit 31 estimates the travel trajectory of the own vehicle based on the detection signals of the sensors 11, 12, and 13 and information on the current position of the own vehicle calculated by the navigation device 14.

Based on the beat signal output from the control unit 22 of the radar device 15, the relative state quantity calculation unit 32 detects the position where the reflected wave received by the radar 21 is generated, that is, the electromagnetic wave transmitted from the radar 21 is generated by the own vehicle. A reflection point at the time of reflection on the surface of an object existing in the outside world is calculated, and a relative state quantity including a relative position and a relative distance between the vehicle and the object is calculated from the reflection point.
The relative speed calculation unit 33 is based on a relative state quantity composed of a relative position and a relative distance between the own vehicle and the object detected by the radar 21, for example, a relative speed between the own vehicle and the object from a time series change of the relative state quantity. Is calculated.

The relative speed correction unit 34 uses a filter based on a predetermined filter time constant (for example, a low-pass filter) to statistically change the relative speed between the vehicle and the object detected by the radar 21 (that is, variation error). Perform correction to reduce.
Further, the relative speed correction unit 34 changes the filter time constant based on the distance of the object with respect to the travel locus of the host vehicle calculated by the object distance calculation unit 35 and the relative distance between the host vehicle and the object.

  For example, the relative speed correction unit 34 changes the filter time constant to an increasing tendency as the distance of the object with respect to the traveling locus of the own vehicle increases with respect to the object having the same relative distance to the own vehicle. For example, in the example shown in FIG. 2 and FIG. 3, for the first to third objects having the same relative distance L with respect to the own vehicle, the travel locus of the own vehicle (own vehicle locus) The first filter time constant C1 is set when the distance D with respect to is less than or equal to zero and less than the predetermined first threshold value D_THR1, and the distance D is greater than or equal to the predetermined first threshold value D_THR1 and less than the predetermined second threshold value D_THR2 (> D_THR1). In this case, the second filter time constant C2 (> C1) is set, and the third filter time constant C3 (> C2) is set when the distance D is equal to or greater than a predetermined second threshold value D_THR2.

The absolute position calculation unit 36 is based on the detection signals of the sensors 11, 12, 13 and the information on the current position of the host vehicle calculated by the navigation device 14, and the relative position between the host vehicle and the object. Based on the above, the absolute position of the object is calculated.
The absolute position storage unit 37 stores the absolute position of the object calculated by the absolute position calculation unit 36 as time series data.
Further, the absolute position calculation unit 36 determines that the absolute position in the lateral direction relative to the traveling direction of the own vehicle (that is, the lateral ground position) has not changed when the amount of change in time series of the absolute position of the object is less than a predetermined value. The predetermined value which is the threshold value of this determination process is set based on the relative distance between the vehicle and the object.
For example, the absolute position calculation unit 36 converts the lateral relative speed between the host vehicle and the object (that is, the relative speed in the lateral direction orthogonal to the traveling direction of the host vehicle) to the lateral ground speed based on the vehicle speed and yaw rate of the host vehicle. If the amount of change in the lateral ground position from the start of detection is equal to or less than a predetermined value, the calculated lateral ground speed is ignored.

  For example, the vehicle control unit 38 outputs the relative speed between the vehicle and the object output from the relative speed calculation unit 33 or the relative speed corrected by the relative speed correction unit 34 and the absolute position output from the absolute position calculation unit 36. Depending on the situation, the alarm output timing and output contents are set, and the travel control that controls the traveling state of the vehicle so as to avoid or reduce the damage caused by collision between the object and the vehicle The execution timing and control content (for example, deceleration during deceleration control, etc.) are set. Then, according to the set control content, a control signal for controlling the deceleration operation by the brake actuator 17, a control signal for controlling the steering operation of the own vehicle steering mechanism (not shown), and the own gear shifting mechanism (not shown). A control signal for controlling the speed change operation, a control signal for controlling the notification operation of the alarm device 18, and the like are output.

For example, as illustrated in FIG. 4, the relative state quantity calculation unit 32 outlines an object from a plurality of reflection points detected on the side surface of an object (for example, another vehicle) existing in the detection area of the radar device 15. Based on the relative speed between the vehicle and the object and the absolute position of the object, a linear movement trajectory with respect to the center of gravity position of the object is calculated. It is calculated as a moving area. Then, the vehicle control unit 38 centers on the moving region of the object and the traveling locus of the own vehicle estimated by the own vehicle locus estimating unit 31 (the own vehicle locus: for example, a linear movement locus with respect to the center of gravity position of the own vehicle). A region intersecting with a belt-like region having a width corresponding to the vehicle width of the own vehicle is set as a collision prediction region.
Then, the vehicle control unit 38 determines the distance Dt from the front end of the host vehicle to the collision prediction area in the travel locus of the host vehicle, the distance Dy1 from the front end of the object to the collision prediction region in the object movement track, and the vehicle of the host vehicle. Based on the distance Dy2 obtained by adding the width corresponding to the width and the length in the direction of the moving locus of the object to the distance Dy1, the vehicle speed Vo of the own vehicle, and the speed Vy in the direction of the moving locus of the object, The vehicle arrival time TTCt (= Dt / Vo) required for the vehicle to reach the collision prediction area, the object arrival time TTCy1 (= Dy1 / Vy) required for the object to reach the collision prediction area, and the object collision An object passage time TTCy2 (= Dy2 / Vy) required for passing through the prediction region is calculated.
Then, the vehicle control unit 38 may cause collision between the own vehicle and the object when the own vehicle arrival time TTCt is longer than the object arrival time TTCy1 and the own vehicle arrival time TTCt is shorter than the object passage time TTCy2. Judge that there is.

The alarm device 18 includes, for example, a tactile transmission device, a visual transmission device, and an auditory transmission device.
The tactile transmission device is, for example, a seat belt device, a steering control device, or the like, and generates a predetermined tension on the seat belt, for example, in response to a control signal input from the vehicle control unit 38 so that the passenger of the own vehicle can feel the tactile sense. There is a possibility of collision with an object by applying a perceptible tightening force or by generating vibration (steering vibration) that can be perceived tactilely by the driver of the vehicle on the steering wheel. Is recognized by the passenger.
The visual transmission device is, for example, a display device or the like, for example, by displaying predetermined alarm information on the display device or blinking a predetermined alarm light in accordance with a control signal input from the vehicle control unit 38. Let the occupant recognize that there is a possibility of collision with the object.
The auditory transmission device is, for example, a speaker or the like, and there is a possibility of occurrence of a collision with an object by outputting a predetermined alarm sound or sound according to a control signal input from the vehicle control unit 38. Is recognized by the passenger.

  The vehicle object detection device 10 according to the present embodiment has the above-described configuration. Next, the operation of the vehicle object detection device 10 will be described.

First, for example, in step S01 shown in FIG. 5, a vehicle state quantity including the vehicle speed, yaw rate, current position, and the like of the host vehicle is acquired.
Next, in step S02, based on the vehicle state quantity of the host vehicle, the travel track of the host vehicle (host vehicle track: for example, a width corresponding to the vehicle width of the host vehicle centered on a linear movement track with respect to the center of gravity position of the host vehicle). Band-like region having

Next, in step S03, the reflection point of the electromagnetic wave transmitted from the radar 21 is calculated, and from this reflection point, the relative position and relative distance between the object present in the detection area of the radar device 15 and the own vehicle are calculated. The relative state quantity is calculated.
Next, in step S04, the relative speed between the vehicle and the object is calculated from the time series change of the relative state quantity.

  Next, in step S05, a filter time constant is set based on the distance of the object with respect to the traveling locus of the own vehicle and the relative distance between the own vehicle and the object. For example, the first filter time constant C1 is set when the distance D with respect to the traveling locus of the own vehicle (the own vehicle locus) is not less than zero and less than a predetermined first threshold value D_THR1, and the distance D is not less than the predetermined first threshold value D_THR1 and The second filter time constant C2 (> C1) is set when it is less than the predetermined second threshold value D_THR2 (> D_THR1), and the third filter time constant C3 (> C2) when the distance D is equal to or greater than the predetermined second threshold value D_THR2. ) Is set.

  Next, in step S06, the relative position between the vehicle and the object (for example, the relative position in the lateral direction orthogonal to the traveling direction of the vehicle, that is, the lateral position) and the relative speed (for example, in the traveling direction of the vehicle) are filtered. Relative velocity in the transverse direction that is orthogonal, that is, lateral velocity) is corrected.

Next, in step S07, a collision prediction area for the vehicle and the object is calculated.
Next, in step S08, the host vehicle arrival time TTCt required for the host vehicle to reach the collision prediction area is calculated.
Next, in step S09, an object arrival time TTCy1 required for the object to reach the collision prediction region and an object passage time TTCy2 required for the object to pass through the collision prediction region are calculated.

Next, in step S10, it is determined whether or not the own vehicle arrival time TTCt is longer than the object arrival time TTCy1 and the own vehicle arrival time TTCt is shorter than the object passage time TTCy2.
When the determination result is “NO”, the series of processes is terminated.
On the other hand, if this determination is “YES”, the flow proceeds to step S11.

Next, in step S11, it is determined whether or not the own vehicle arrival time TTCt is less than a predetermined threshold time TTCthr (for example, 2.5 seconds). The predetermined threshold time TTCthr is, for example, the time required for the vehicle state to actually change with the start of execution of collision avoidance control described later (for example, the brake is actually applied from the start of the deceleration operation by the brake actuator 17). The upper limit of the time until the start etc.).
When the determination result is “NO”, the series of processes is terminated.
On the other hand, if this determination is “YES”, the flow proceeds to step S12.

In step S12, the alarm control for controlling the notification operation of the alarm device 18 so as to avoid the occurrence of a collision between the object and the vehicle or reduce the damage at the time of the collision and the driving for controlling the traveling state of the vehicle. The execution of collision avoidance control including control is started.
In step S13, for example, the execution of the collision avoidance control is stopped after a predetermined set time (for example, 1 second) after the vehicle state actually starts to change with the start of the execution of the collision avoidance control. A series of processing ends.

As described above, according to the vehicle object detection device 10 according to the present embodiment, the filter time constant is changed based on the distance of the object with respect to the traveling locus of the own vehicle. The position detection error can be appropriately reduced for an object that is relatively far away from the vehicle, and an object that is relatively close to the vehicle's travel locus and position (for example, the vehicle's For other vehicles crossing the travel locus, etc., position detection can be performed quickly.
In addition, when the amount of change in the absolute position of the object in the time series is less than a predetermined value, it is recognized that the absolute position in the lateral direction with respect to the traveling direction of the vehicle has not changed. Can be prevented from being erroneously calculated. In addition, since a predetermined value that is a determination threshold is set according to the degree of position detection error that changes according to the relative distance, it is possible to more accurately prevent erroneous calculation of the absolute position due to the position detection error. Can do.

It is a block diagram of the vehicle object detection apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the filter time constant which changes according to the distance of the object with respect to the traveling locus of the own vehicle. It is a figure which shows the 1st-3rd object which has the equivalent relative distance L with respect to the own vehicle. It is a figure which shows an example of the collision prediction area | region with the own vehicle and the object (for example, other vehicle) which exists in the detection area of a radar apparatus. It is a flowchart which shows operation | movement of the vehicle object detection apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle object detection apparatus 15 Radar apparatus (transmission / reception means)
31 Vehicle track estimation unit (travel track prediction means)
32 Relative state quantity calculation unit (relative state quantity calculation means)
33 Relative speed calculation unit (relative speed calculation means)
34 Relative speed correction unit (relative speed correction means)
36 Absolute position calculation unit (absolute position calculation means)

Claims (3)

Transmitting and receiving means for transmitting an electromagnetic wave over a predetermined angle around the vehicle at a predetermined time interval and receiving a reflected wave of the electromagnetic wave from an object existing around the vehicle;
Relative state quantity calculating means for calculating a relative state quantity composed of a relative position and a relative distance between the vehicle and the object based on the reflected wave;
A relative speed calculating means for calculating a relative speed between the vehicle and the object based on the relative state quantity;
A relative speed correcting means for correcting the relative speed by a predetermined filter time constant;
A travel locus prediction means for predicting the travel locus of the vehicle based on the movement state of the vehicle,
The relative speed correction means changes the filter time constant based on the distance of the object with respect to the travel locus ,
Absolute position calculating means for calculating the absolute position of the object based on the movement state of the host vehicle and the relative position;
The absolute position calculation means recognizes that the absolute position in the lateral direction relative to the traveling direction of the vehicle has not changed when the amount of change in the time series of the absolute position is less than a predetermined value . Object detection device. The vehicle object detection device according to claim 1, wherein the absolute position calculation unit sets the predetermined value based on the relative distance. The relative speed correction unit is configured to detect the object having the same relative distance with respect to the own vehicle with respect to the traveling locus of the own vehicle based on the relative distance and the distance of the object with respect to the traveling locus. The vehicle object according to claim 1 or 2 , wherein the filter time constant is changed so that the filter time constant changes in an increasing tendency as the distance of the object increases. Detection device.

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