JP2015105836A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake device configured to accurately determine whether a detected object is a ghost or not, and to execute brake control on an existing object out of the detected objects more accurately.SOLUTION: A brake device detects an absolute speed of a vehicle, detects an object ahead of the vehicle, calculates a distance from the vehicle to the object and a relative speed, and calculates a predicted distance in a certain point of time, on the basis of a distance and a relative speed obtained earlier than the certain point of time and stored in storage means, determines whether the detected object is a ghost or not, on the basis of the absolute speed, an absolute speed of the object calculated from the relative speed, and a comparison between the predicted distance and the calculated distance, to perform predetermined brake control on the basis of the object determined not to be a ghost.

Description

  The present invention relates to a braking device for avoiding a collision with an obstacle.

  An object detection unit such as an electronic scan type millimeter wave radar may detect a ghost (non-existent object) within a detection range. For example, since a weak transmission wave is transmitted outside the detection range, if there are continuous objects with high reflection intensity outside the detection range, the object with high reflection intensity is a level that can be received by the millimeter wave radar. May return the reflected wave. Therefore, a millimeter wave radar that has received a reflected wave from an object having a high reflection intensity outside the detection range may detect the object as an object within the detection range, that is, a ghost. Further, when braking control is performed for avoiding a collision with an object detected by the millimeter wave radar, braking control for a ghost that does not actually exist in front of the host vehicle is performed, which may give the driver a feeling of strangeness.

  Therefore, conventionally, when a movement trajectory is estimated from the relative positions of objects detected at a plurality of locations in the detection range, and an object is detected on the estimated movement trajectory, it is determined that the detected object is highly likely. A vehicle object detection device has been proposed (for example, Patent Document 1). As a result, it is possible to determine an object with low probability among detected objects, that is, an object with a possibility of ghosting.

JP 2006-292518 A

  However, in the vehicle object detection device according to Patent Document 1, there is a risk that it is determined that the probability of an actual object is low. For example, when an object detected at a plurality of locations in the detection range changes its movement direction, the estimated movement trajectory does not overlap with the actual movement trajectory, and the probability that the detected object is an actual object is low. It can be judged. For this reason, when braking control is performed for avoiding a collision with an object detected by the vehicle object detection device, there is a possibility that the braking control for an actual object cannot be performed accurately.

  Therefore, in view of the above problems, it is possible to more accurately determine whether or not the detected object is a ghost, and it is possible to more accurately execute the braking control on an actual object among the detected objects. The purpose is to provide.

In order to achieve the above object, in one embodiment, a braking device comprises:
Speed detecting means for detecting the absolute speed of the host vehicle;
Object detection means for detecting an object in front of the host vehicle and acquiring information related to the relative position of the object;
Based on the information acquired by the object detection means, a distance calculation means for calculating a distance from the host vehicle to the object;
A relative speed calculating means for calculating a relative speed of the object with respect to the host vehicle based on the information acquired by the object detecting means;
Storage means for storing the distance and the relative speed;
Prediction means for calculating a predicted distance as a predicted value of the distance at the certain time point based on the distance and the relative speed in the past from the certain time point stored in the storage means;
The object detection means based on the absolute speed of the object calculated from the absolute speed and the relative speed calculated by the relative speed calculation means, and a comparison between the predicted distance and the distance calculated by the distance calculation means Determining means for determining whether or not the object detected by the method is a ghost;
Control means for performing predetermined braking control based on an object determined not to be a ghost by the determination means.

  According to the present embodiment, it is possible to more accurately determine whether or not the detected object is a ghost, and to perform braking control that can more accurately execute the braking control on an actual object among the detected objects. An apparatus can be provided.

It is a block diagram which shows an example of a structure of a braking device. It is a figure explaining the characteristic of the ghost target detected by a millimeter wave radar. It is a flowchart which shows operation | movement of the braking device (PCS ECU) which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the braking device (PCS ECU) which concerns on 1st Embodiment. It is a figure explaining the calculation method of prediction distance. It is a flowchart which shows operation | movement of the braking device (PCS ECU) which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the braking device (PCS ECU) which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram illustrating an example of a configuration of a braking device 1 according to the present embodiment.

  The braking device 1 in the present embodiment is mounted on a vehicle and performs braking by intervention in order to avoid collision of the vehicle with an object. The vehicle may be any vehicle, may be a vehicle using an engine as a driving force source, may be a hybrid vehicle, or may be an electric vehicle using only an electric motor as a driving force source. Good. In the following, the “object” is a concept including a moving body and a fixed object that may exist around the host vehicle, and is, for example, another vehicle or a guardrail.

  The braking device 1 includes a millimeter wave radar 10, a stereo camera 15, a millimeter wave radar ECU 20, a stereo camera ECU 25, a wheel speed sensor 30, a yaw rate sensor 35, a PCS ECU 40, a brake ECU 50, a brake actuator 60, and the like. Further, as elements related to the braking device 1, the vehicle on which the braking device 1 is mounted may include a meter ECU 70, a combination meter 80, a notification sound generating device 85, and the like.

  The millimeter wave radar 10 is a means for detecting an object in front of the host vehicle, and may be mounted, for example, near the center of the vehicle front bumper or the front grill in the vehicle width direction (left-right direction). The millimeter wave radar 10 can detect an object by transmitting a radio wave of a millimeter wave band (for example, 60 GHz) toward a predetermined range and receiving the reflected wave. Further, the millimeter wave radar ECU 20 described later recognizes an object based on a reflected wave signal received by the millimeter wave radar 10, and calculates a relative position (distance, azimuth) and relative speed of the object with respect to the host vehicle. be able to. Specifically, the distance from the object to the vehicle is calculated based on the time difference (frequency difference) between the transmitted radio wave and the received reflected wave, and the transmitted radio wave and the received reflected wave are calculated using the Doppler effect. Based on the change in frequency, the relative speed of the object with respect to the host vehicle may be calculated. Further, the millimeter wave radar 10 has a plurality of antennas that receive reflected waves from the object, and the direction of the object viewed from the own vehicle by the phase difference of the reflected waves from the obstacle received by the plurality of antennas. It may be calculated. In the following, “object relative distance” means the distance from the host vehicle to the object, and “object relative speed” means the object relative speed with respect to the host vehicle, and “object orientation”. Means the orientation of the object as seen from the host vehicle.

  The stereo camera 15 is an imaging unit that images the front of the host vehicle. A stereo camera ECU 25 to be described later can detect an object ahead of the host vehicle based on image information captured by the stereo camera 15 and calculate a relative position (distance, azimuth) of the object with respect to the host vehicle.

  The millimeter wave radar ECU 20 is communicably connected to the millimeter wave radar 10 via an in-vehicle LAN, a direct line, etc. As described above, based on the reflected wave signal received from the millimeter wave radar 10, the relative position of the detected object, Calculate the relative speed. The millimeter wave radar ECU 20 outputs information (target information) about the detected object including the calculated relative position and relative speed of the object to the PCS ECU 40 described later.

  The stereo camera ECU 25 is communicably connected to the stereo camera 15 via an in-vehicle LAN, a direct line, or the like, and calculates the relative position of the detected object based on the image information received from the stereo camera 15 as described above. Stereo camera ECU25 outputs the information (target information) regarding the detected object containing the calculated relative position of the object to PCS ECU40 mentioned later.

  The wheel speed sensor 30 is a means for detecting the wheel speed of the host vehicle, and can calculate the speed (absolute speed) of the host vehicle from the detected wheel speed. As the wheel speed sensor 30, any sensor may be used as long as it can detect the wheel speed.

  The yaw rate sensor 35 is a means for detecting the yaw rate (rotational angular velocity in the yaw direction) of the host vehicle. As the yaw rate sensor 35, any sensor that can detect the yaw rate of the host vehicle may be used.

  The PCS ECU 40 is an electronic control unit that performs predetermined braking control based on an object detected by the millimeter wave radar 10 and the stereo camera 15, for example, collision avoidance braking control by intervention for avoiding a collision with the detected object. . Specifically, the target information received from the millimeter wave radar ECU 20, the stereo camera ECU 25, the wheel speed sensor 30, the yaw rate sensor 35, etc. that are communicably connected via an in-vehicle LAN or the like and the state of the host vehicle (vehicle speed, yaw rate, etc.) Based on the above, it may be determined whether there is a high possibility that the object and the vehicle collide (collision determination). When it is determined that there is a high possibility that the object and the host vehicle collide with each other, an intervention braking request may be output to a brake ECU 50 described later to generate a braking force due to the intervention. For example, when the TTC (Time To Collision) is calculated from the vehicle speed of the subject vehicle and the relative distance between the subject as an index of the possibility of collision between the subject and the subject vehicle, and the TTC falls below the threshold value It may be determined that the possibility of collision with the object is high. Further, based on the vehicle speed of the host vehicle, the relative distance of the object, and the brake operation (brake operation amount) by the driver, by determining whether it is possible to avoid collision with the object detected by the brake operation, A collision determination may be made. Note that the relative distance of the detected object used when calculating the TTC may be the relative distance calculated by the millimeter wave radar ECU 20. Further, when the object detected by the millimeter wave radar 10 is also detected in the stereo camera 15, the detected object is detected by averaging from the target information transmitted from the millimeter wave radar ECU 20 and the stereo camera ECU 25. The target information may be reconstructed. In this case, the relative distance of the detected object included in the reconstructed target information may be used in the calculation of TTC. Hereinafter, reconstructing the target information based on both the target information of the object detected by the millimeter wave radar 10 and the target information of the object detected by the stereo camera 15 is referred to as “fusion”. When the relative position of the object detected by the millimeter wave radar 10 and the relative position of the object detected by the stereo camera 15 are close, it is determined that the object detected by the millimeter wave radar 10 is detected by the stereo camera 15. To do. For example, when the relative position of the object detected by the stereo camera 15 is included in a predetermined range centered on the relative position of the object detected by the millimeter wave radar 10, the object detected by the millimeter wave radar 10 is a stereo camera. 15 may be determined to be detected.

  Further, the PCS ECU 40 may provide driving assistance for notifying the driver of the possibility of collision with an object detected by the millimeter wave radar 10 and the stereo camera 15 via the meter ECU 70 described later. Specifically, the meter ECU 70 may be connected to a combination meter 80 that performs display notification to the driver, a notification sound generator 85 that performs voice notification to the driver, and the like. The meter ECU 70 controls numerical values, characters, figures, indicator lamps, and the like displayed on the combination meter 80 in response to a notification request from the PCS ECU 40, and also generates an alarm sound or alarm to be notified by the notification sound generator 85. Voice control may be performed. For example, when the PCS ECU 40 determines that there is a high possibility of collision with an object detected by the millimeter wave radar 10 and the stereo camera 15, the PCS ECU 40 notifies the driver of the possibility of collision with the object to the meter ECU 70. May be requested to output an alarm sound or turn on an indicator lamp.

  Further, the PCS ECU 40 determines whether or not the object detected by the millimeter wave radar 10 is a ghost (non-existent object) based on the target information received from the millimeter wave radar ECU 20. Specifically, a ghost probability as a probability that the object detected by the millimeter wave radar 10 is a ghost is calculated based on the target information received from the millimeter wave radar ECU 20, and the ghost probability is equal to or higher than a predetermined threshold value. In some cases, the object is determined to be a ghost. Details of a method for determining whether or not the object detected by the millimeter wave radar 10 is a ghost will be described later.

  Further, when the PCS ECU 40 determines that the object detected by the millimeter wave radar 10 is a ghost, the PCS ECU 40 prohibits the braking control and the driving support based on the detected object (ghost). That is, the PCS ECU 40 does not output an intervention braking request for avoiding a collision with an object determined to be a ghost. In addition, a notification request for notifying the possibility of collision with an object determined to be a ghost is not output. As a result, it is possible to suppress a driver's uncomfortable feeling due to execution of braking control and driving assistance based on an object that does not exist.

  The brake ECU 50 is an electronic control unit that performs braking control of the vehicle, for example, by controlling a brake actuator 60 that operates a hydraulic brake device disposed on each wheel. In the present embodiment, the brake ECU 50 controls the output (wheel cylinder pressure) of the brake actuator 60 in response to an intervention braking request received from the PCS ECU 40 that is communicably connected via an in-vehicle LAN or the like, and generates a braking force due to the intervention. Let For example, when an intervention braking request from the PCS ECU 40 is received, a braking force by intervention necessary to avoid a collision may be determined according to the above-described TTC, and the braking force may be generated. Specifically, the braking force by the intervention may be increased in accordance with a decrease in TTC, which is a direction in which the possibility of collision with a detected object is increased. Further, it may be determined whether or not the braking force generated by the intervention is generated in consideration of the brake operation by the driver. Specifically, when an intervention braking request is received from the PCS ECU 40 and it can be determined that an emergency brake operation has been performed in consideration of the driver's brake operation (brake operation amount and brake operation speed). A braking force by intervention may be generated. Further, when an object detected by the millimeter wave radar 10 is also detected by the stereo camera 15, that is, when the target information of the millimeter wave radar 10 and the stereo camera 15 can be fused, the object is not a ghost, It can be determined that the possibility of being an actual object is very high. Therefore, when the target information of the millimeter wave radar 10 and the stereo camera 15 can be fused, it is generated by intervention for avoiding a collision with an object detected by the millimeter wave radar 10 as compared to the case where the fusion is impossible. The braking force to be applied may be increased. In the case of a hybrid vehicle or an electric vehicle, braking control may be performed by controlling motor output (regenerative operation) based on an intervention braking request from the PCS ECU 40.

  The brake actuator 60 may include a pump that generates high-pressure oil (and a motor that drives the pump), various valves, a hydraulic circuit, and the like. The hydraulic circuit configuration is arbitrary, and any configuration that can increase the wheel cylinder pressure regardless of the amount of depression of the driver's brake pedal is acceptable. Typically, a high-pressure hydraulic source other than the master cylinder (high-pressure oil is used). It only has to be provided with a pump or accumulator to be generated. A circuit configuration typically used in a brake-by-wire system represented by ECB (Electric Control Braking System) may be employed.

  The millimeter wave radar ECU 20, the stereo camera ECU 25, the PCS ECU 40, and the brake ECU 50 described above may be configured by a microcomputer and execute various control processes by executing various programs stored in the ROM on the CPU. The functions of the millimeter wave radar ECU 20, the stereo camera ECU 25, the PCS ECU 40, and the brake ECU 50 may be realized by arbitrary hardware, software, firmware, or a combination thereof. Further, some or all of the functions of the millimeter wave radar ECU 20, the stereo camera ECU 25, the PCS ECU 40, and the brake ECU 50 may be realized by another ECU. Further, the millimeter wave radar ECU 20, the stereo camera ECU 25, the PCS ECU 40, and the brake ECU 50 may realize part or all of the functions of other ECUs. For example, some or all of the functions of the millimeter wave radar ECU 20 may be realized by the PCS ECU 40, and some or all of the functions of the stereo camera ECU 25 may be realized by the PCS ECU 40. Further, part or all of the functions of the PCS ECU 40 may be realized by the brake ECU 50, and part or all of the functions of the brake ECU 50 may be realized by the PCS ECU 40.

  Next, a method for determining whether or not the object detected by the braking device 1 is a ghost will be specifically described.

  The braking device 1 according to the present embodiment determines whether or not the detected object is a ghost based on the characteristics of the ghost detected by the millimeter wave radar 10. First, the characteristics of the ghost detected by the millimeter wave radar 10 will be described with reference to FIG.

  FIG. 2 is a diagram for explaining the characteristics of a ghost target detected by a millimeter wave radar. A situation in which the vehicle 100 on which the braking device 1 (millimeter wave radar 10) is mounted is traveling at a vehicle speed Vc from the bottom to the top in the figure is shown in plan view. The millimeter wave radar 10 is provided at the center of the front end of the vehicle 100, and transmits a detection wave having strong directivity to the vehicle front side and a symmetrical detection range 10a. For example, the detection range 10a may be set as an angle range of α ° (for example, 15 °) from the millimeter wave radar 100 with respect to the traveling direction of the vehicle 100 in plan view. In addition, an object (hereinafter referred to as a reflector row) 200 having a high reflection intensity is installed beside the lane in which the vehicle 100 travels.

  The transmission wave transmitted from the millimeter wave radar 10 is transmitted so as to have a high intensity in the detection range 10a. However, in principle, there is no transmission wave outside the detection range. Therefore, the reflector 300 in the reflector row 200 beside the lane may return a weak transmitted wave as a reflected wave having an intensity that can be detected by the millimeter wave radar 10.

  As described above, the millimeter wave radar 10 (millimeter wave radar ECU 20) calculates the direction of the detected object based on the phase difference of the reflected waves received by the plurality of antennas. However, in the angle range exceeding the detection range, the phase difference of the reflected waves received by the plurality of antennas exceeds 2π, so the direction of the detected object cannot be uniquely determined. Therefore, since the phase difference of the reflected wave from the reflector 300 outside the detection range received by the plurality of antennas exceeds 2π, the millimeter wave radar 10 (millimeter wave radar ECU 20) accurately detects the orientation of the reflector 300. In some cases, the reflector 300 may be detected (calculated) as a ghost target 300g within the detection range. And since the continuous reflector 300 is installed as the reflector row | line | column 200, the ghost target 300g may be detected continuously.

  Here, the following three are mentioned as the characteristics of the ghost target 300g. Hereinafter, the features of (1) to (3) will be listed and specifically described with reference to FIG.

(1) The range in which the ghost target 300g is detected is limited to a short distance.
The ghost target 300g is detected (calculated) as a target having the same relative distance as the reflector 300 by the millimeter wave radar 10 (millimeter wave radar ECU 20). Therefore, when the reflector 300 returns a weak transmission wave outside the detection range as a reflected wave that can be detected by the millimeter wave radar 10, the ghost target 300g is detected. The possibility of being detected as a target 300 g is low. That is, the range in which the ghost target 300g is detected is limited to a short distance.

(2) The relative speed of the ghost target 300g is detected (calculated) as a speed approaching the vehicle 100 by the millimeter wave radar 10 (millimeter wave radar ECU 20), but the relative position of the ghost target 300g is substantially changed. do not do.
As described above, the millimeter wave radar 10 (millimeter wave radar ECU 20) detects (calculates) the relative speed of the reflector 300 based on the Doppler effect. Therefore, the detected relative speed is the relative speed Vre0 of the reflector 300 (the magnitude is equivalent to the vehicle speed (absolute speed) Vc of the vehicle 100, and the direction is opposite to the traveling direction of the vehicle 100). A line segment direction component Vre1 connecting the reflector 300 and the millimeter wave radar 10 (hereinafter referred to as a radar direction component Vre1). The radar direction component Vre1 is a relative speed in a direction approaching the vehicle 100 (millimeter wave radar 10). Therefore, the relative speed Vre2 of the ghost target 300g has the same magnitude as the radar direction component Vre1 and has a direction component approaching the vehicle 100 (millimeter wave radar 10), that is, opposite to the traveling direction of the vehicle 100. Detected as speed.
On the other hand, the ghost target 300g continuously detected by the millimeter wave radar 10 is obtained by detecting a different reflector 300 from time to time, and is reflected in the same direction as viewed from the vehicle 100 (millimeter wave radar 10). Since the body 300 is detected, the relative position hardly fluctuates.

(3) The ghost target 300g is detected by the millimeter wave radar 10 (millimeter wave radar ECU 20) as a vehicle traveling in front of the vehicle 100, not a stationary object.
Since the reflector 300 is a fixed object (stationary object) beside the lane, the reflector 300 has a relative speed Vre0 equivalent to the vehicle speed Vc of the vehicle 100 in the direction opposite to the traveling direction of the vehicle 100. However, as described above, the relative speed of the reflector 300 detected (calculated) by the millimeter wave radar 10 (millimeter wave radar ECU 20) is a line segment connecting the reflector 300 and the millimeter wave radar 10 in the relative speed Vre0. It is detected (calculated) as the direction component Vre1. The radar direction component Vre1 is a relative speed in a direction approaching the vehicle 100 (millimeter wave radar 10) as described above. Therefore, the magnitude of the relative speed Vre2 of the ghost target 300g is detected as a speed having a direction component that is smaller than the absolute speed of the vehicle speed Vc of the vehicle 100 and approaches the vehicle 100 (millimeter wave radar 10). Therefore, the absolute speed of the ghost target calculated as the sum of the vehicle speed Vc of the vehicle 100 and the relative speed of the ghost target 300g has an absolute value larger than 0 and is the speed in the same direction as the traveling direction of the vehicle 100. Detected. That is, the millimeter wave radar 10 (millimeter wave radar ECU 20) recognizes the ghost target 300g as a vehicle traveling in front of the vehicle 100.

  Hereinafter, a method in which the braking device 1 (PCS ECU 40) determines whether or not the detected object is a ghost will be specifically described using the above-described (1) to (3) that are characteristics of the ghost. In the following determination method, all of the ghost features (1) to (3) are used. For example, the determination may be performed using (2) which is the main ghost feature, The determination may be performed using the ghost features (2) and (3).

  3 and 4 are flowcharts showing the operation of the braking device 1 (PCS ECU 40) according to the present embodiment. Specifically, it is a flowchart showing a process of calculating a ghost probability of the detected object by the braking device 1. 3 and 4 is executed every predetermined period, for example, every update period of the millimeter wave radar 10, from when the ignition switch of the vehicle is turned on until it is turned off. In the following, the update timing of the millimeter wave radar 10 in which the processing shown in FIGS. 3 and 4 is performed will be referred to as “update timing”.

  Here, for simplicity of explanation, symbols are defined. The relative distance of the object detected by the millimeter wave radar 10 is assumed to be Ds (hereinafter simply referred to as the relative distance Ds). The relative velocity of the object detected by the millimeter wave radar 10 is assumed to be Vs (hereinafter simply referred to as relative velocity Vs). Further, the absolute velocity (target velocity) of the object detected by the millimeter wave radar 10 is assumed to be Vtgt (hereinafter simply referred to as the target velocity Vtgt). The vehicle speed (absolute speed) of the host vehicle is Vc (hereinafter simply referred to as vehicle speed Vc). Further, the relative distance (predicted distance) of the object detected by the millimeter wave radar 10 predicted from the relative distance and relative speed of the object detected by the millimeter wave radar 10 at the update time of the past millimeter wave radar 10 is represented by Dest ( Hereinafter, it is simply referred to as a predicted distance Dest). A measurement error related to the distance of the millimeter wave radar 10 is assumed to be ΔDs (hereinafter simply referred to as measurement error ΔDs). In the following, for each speed (absolute speed, relative speed), the traveling direction of the host vehicle is positive, and the direction toward the host vehicle is negative. 3 and 4, the object detected by the millimeter wave radar 10 is simply referred to as “detected object”.

  3 and 4, the PCS ECU 40 sets three parameters, a ghost candidate flag, a ghost counter, and a ghost probability, and confirms the set ghost candidate flag and ghost counter values. Proceed with the process. The ghost candidate flag, the ghost counter, and the ghost probability are maintained as long as the object is continuously detected by the millimeter wave radar 10. The ghost candidate flag is a flag set as a ghost candidate. The flag is turned on when it is determined that the detected object is a ghost candidate, and is turned off when it is determined that the detected object is not a ghost candidate. The ghost counter is a counter for determining whether or not to move to the processing flow of FIG. 4 (step S106 below). Further, the millimeter wave radar 10 (millimeter wave radar ECU 20) cannot determine whether the detected object is a new target or an object that is continuously detected because the received reflected wave is weak. There is a case. Therefore, an indeterminate flag is set as a flag indicating whether or not the detected object is a new target or a continuously detected object. The millimeter wave radar ECU 20 may include an indeterminate flag in the target information. If the determination cannot be made, the millimeter wave radar ECU 20 sets the indeterminate flag to ON and transmits it to the PCS ECU 40. Further, when the uncertain flag is ON, the PCS ECU 40 executes the following processing flow assuming that the detected object is an object that is continuously detected.

  Steps S101 to S105 determine whether or not the newly detected object (new target) is an object (ghost candidate) that may be a ghost, and the ghost candidate flag, ghost counter, and initial ghost probability This is a step for setting.

  First, in step S101, it is determined whether or not the detected object is a new target. If the detected object is not a new target, the process proceeds to step S105. If the detected object is a new target, the process proceeds to step S102.

  In step S102, it is determined whether or not the newly detected object matches the above-described ghost features (1) and (3). Specifically, the relative distance Ds is equal to or less than a predetermined distance TH1 (characteristic (1) described above), and the target speed Vtgt (= vehicle speed Vc + relative speed Vs) is equal to or higher than a predetermined speed TH2 (described above (3)). It is determined whether or not it is a feature of the above. If the condition is satisfied, the process proceeds to step S103. If the condition is not satisfied, the process proceeds to step S105. The predetermined distance TH1 may be determined as appropriate based on, for example, the attenuation rate with respect to the distance of the transmission wave from the millimeter wave radar 10, the reflectance of the reflector on the side of the assumed lane, and experiments on these. . The predetermined speed TH2 may be set, for example, as the maximum value of the relative speed measurement error detected (calculated) by the millimeter wave radar 10 (millimeter wave radar ECU 20).

  Here, whether or not the detected object matches the above-described feature (2) depends on the relative distance Ds and the relative update time of the millimeter-wave radar 10 in the past, as shown in step S118 in FIG. This is determined by comparison with the relative distance (predicted distance) Dest of the detected object predicted from the distance and the relative speed. That is, the determination can be made based on whether or not the relative distance Ds of the detected object is greater than the prediction distance Dest by the measurement error ΔDs of the millimeter wave radar 10 or more. However, when the relative velocity Vs detected (calculated) by the millimeter wave radar 10 (millimeter wave radar ECU 20) is small, whether the detected relative velocity is due to the measurement error of the millimeter wave radar 10 or the actually detected object It may be difficult to determine whether the relative speed is. Therefore, for example, it is determined whether or not the above condition is satisfied by the relative distance Ds at the update time of the millimeter wave radar 10 this time, the relative distance Ds at the update time of the previous millimeter wave radar, and the predicted distance Dest by the relative velocity Vs. Then, accurate determination may not be performed due to the measurement error ΔDs. Therefore, in the processing flow of FIG. 3 (specifically, step S111 described later), the relative distance Ds and the relative speed Vs are stored (buffered) in a history, and the relative position before a plurality of times (predetermined number N times). Is used as a reference to calculate a predicted distance Dest. Thereby, in the case where the detected object is a ghost, a sufficient difference between the relative distance Ds and the predicted distance Dest can be provided, so that the influence of the measurement error can be suppressed. In this flowchart, the number of times the relative distance Ds and relative speed Vs of the detected object are buffered is counted by counting up the ghost counter.

  Returning to the flowchart, in step S103, the ghost candidate flag is set to “ON” for the newly detected object, the ghost probability is set to “20%” as an initial value, and the process proceeds to step S104. In step S104, the relative distance Ds and the relative speed Vs at the update time of the current millimeter wave radar are stored (buffered) in the internal RAM or the like, the ghost counter is set to “1”, and the current process is performed. finish.

  In step S105, for the newly detected object, the ghost candidate flag is set to “OFF”, the ghost probability is set to “0%”, and the current process ends.

  Next, steps S106 to S115 are a ghost probability calculation (setting) flow for an object that is continuously detected by the millimeter wave radar 10, and a period (number of times) in which the object is detected by the millimeter wave radar 10. Shows a flow when is relatively short (small).

  First, in step S106, it is determined whether or not a ghost candidate flag is ON. If the ghost candidate flag is ON, the process proceeds to step S106. If the ghost candidate flag is OFF, the current process is stopped.

  In step S107, as described above, it is determined whether or not to move to the flow for calculating the ghost probability including the ghost feature (2). It is determined whether or not the value of the ghost counter, which is the number of times the relative distance Ds and the relative speed Vs are buffered, is smaller than the predetermined number N. If the value of the ghost counter is smaller than the predetermined number N, the process proceeds to step S108. When the value of the ghost counter is equal to or greater than the predetermined number N, the process proceeds to A and proceeds to the flowchart of FIG.

  In step S108, it is determined whether or not the uncertain flag is ON. When the uncertain flag is ON, it is a case where it is not possible to determine whether the detected object is a new target or an object that is continuously detected because the received reflected wave is weak. Therefore, if the uncertain flag is ON, the process proceeds to step S109, where it is considered that the detected object is likely to be a ghost, the ghost probability is increased by 5%, and the current process is terminated. If the uncertain flag is OFF, the process proceeds to step S110.

  When the uncertain flag is ON, the relative distance Ds and the relative speed Vs cannot be calculated by the millimeter wave radar ECU 20, so the relative distance Ds and the relative speed Vs are not buffered, and the ghost counter is also counted up. do not do.

  In step S110, it is determined whether or not the continuously detected object matches the above-described ghost features (1) and (3). Specifically, the relative distance Ds is equal to or less than a predetermined distance TH1 (characteristic (1) described above), and the target speed Vtgt (= vehicle speed Vc + relative speed Vs) is equal to or higher than a predetermined speed TH2 (described above (3)). It is determined whether or not it is a feature of the above. If the condition is satisfied, the process proceeds to step S111. If the condition is not satisfied, the process proceeds to step S113.

  In step S111, the ghost probability is increased by 5%, and the process proceeds to step S112. In step S112, the relative distance Ds and the relative speed Vs at the update time of the current millimeter wave radar 10 are stored (buffered) in an internal RAM or the like, the ghost counter is incremented by 1, and the current process ends. To do.

  In step S113, the ghost probability is reduced by 2%, and the process proceeds to step S114.

  In step S114, it is determined whether the ghost probability is 0% or less. When the ghost probability is 0% or less, the process proceeds to step S115, where the ghost candidate flag of the detected object is turned OFF, and the relative distance Ds and the relative speed Vs that are historically stored in the internal RAM or the like are deleted (buffer) After clearing, the current process is terminated. If the ghost probability is not less than 0%, the current process is terminated.

  Next, a flow for an object having a relatively long (large) period (number of times) detected by the millimeter wave radar 10 will be described. That is, the flow when the value of the ghost counter is large enough to eliminate the influence of the measurement error of the millimeter wave radar 10 when comparing the relative distance Ds and the predicted distance Dest will be described with reference to FIG. To do.

  As described above, when the value of the ghost counter is equal to or greater than the predetermined number N in step S106 in FIG. 3, the process proceeds to the processing flow in FIG. 4 (step S116).

  In step S116, it is determined whether or not the uncertain flag is ON. If the indeterminate flag is ON, the process proceeds to step S117, and similarly to step S109, it is considered that the detected object is likely to be a ghost, the ghost probability is increased by 10%, and the current process is terminated. If the uncertain flag is OFF, the process proceeds to step S118.

  In step S118, a predicted distance Dest that is a relative distance predicted from the relative distance Ds and the relative speed Vs at the update time of the past millimeter wave radar 10 is calculated, and the process proceeds to step S119.

  Here, a method of calculating the predicted distance Dest will be described with reference to FIG.

  FIG. 5 is a diagram illustrating a method for calculating a predicted distance. The ghost counter values ((1) to (10)) are shown on the horizontal axis, and the ranges of the relative distance Ds and the relative speed Vs used for calculating the predicted distance Dest are schematically shown. In this figure, a case where N = 7 will be described as an example of the predetermined number of times N. In the following description, i is an integer equal to or greater than 1, and the relative distance Ds, the relative speed Vs, and the predicted distance Dest corresponding to the ghost counter value i (hereinafter referred to as ghost counter (i)) are set to Ds ( i), Vs (i), Dest (i), and the update period of the millimeter wave radar 10 is Ts.

  As described above, when the value of the ghost counter is between 1 and 6, the predicted distance is not calculated, and the relative distance Ds and the relative speed Vs are buffered by the processing flow of steps S101 to S115.

  When the ghost counter becomes 7 or more, the process proceeds to the flow shown in FIG. 4 by the determination in step S106, and thus the predicted distance is calculated in step S118 as described above.

  When the value of the ghost counter is 7, a predicted distance Dest (8) corresponding to the ghost counter (8) (current update time) is calculated based on the relative distance Ds (1) corresponding to the ghost counter (1). To do. When the ghost counter is 8, the predicted distance Dest (9) corresponding to the ghost counter (9) (current update time) is calculated based on the relative distance Ds (2) corresponding to the ghost counter (2). To do. When the ghost counter is 9, a predicted distance Dest (10) corresponding to the ghost counter (10) (current update time) is calculated with reference to the ghost counter (3).

  Specifically, in the case where the value of the ghost counter is 7, for example, Dest (8) = Ds (1) + Ts × {Vs (1) + Vs (2) + Vs (3) + Vs (4) + Vs (5) The predicted distance Dest may be calculated as + Vs (6) + Vs (7)}.

  Thus, the predicted distance Dest can be calculated using the relative distance Ds and the relative speed Vs for the past update timings N retroactively from the current update timing of the millimeter wave radar 10.

  Returning to FIG. 5, in step S119, it is determined whether or not the detected object matches the above-described ghost features (1) to (3). Specifically, the relative distance Ds is equal to or less than a predetermined distance TH1 (characteristic (1) described above), and the target speed Vtgt (= vehicle speed Vc + relative speed Vs) is equal to or higher than a predetermined speed TH2 (described above (3)). And the relative distance Ds is larger than the predicted distance Dest by the measurement error ΔDs of the millimeter wave radar 10 or more (feature (2) described above). If the condition is satisfied, the process proceeds to step S120. If the condition is not satisfied, the process proceeds to step S122.

  In step S120, the ghost probability is increased by 10%, and the process proceeds to step S121. In step S121, the relative distance Ds and the relative velocity Vs of the object at the update time of the millimeter wave radar 10 are stored (buffered) in an internal RAM or the like, and the ghost counter is incremented by 1 to perform the current process. Exit.

  In step S122, the ghost probability is reduced by 5%, and the process proceeds to step S123.

  In step S123, it is determined whether or not the ghost probability is 0% or less. When the ghost probability is 0% or less, the process proceeds to step S124, the ghost candidate flag of the detected object is turned OFF, and the detected object relative distance Ds and relative speed stored in the internal RAM or the like are historically stored. After erasing Vs (buffer clear), the current process is terminated. If the ghost probability is not less than 0%, the current process is terminated.

  Thus, for example, the PCS ECU 40 performs the ghost probability calculation processing according to the flowcharts shown in FIGS. 3 and 4 described above for the object detected by the millimeter wave radar 10 at each update period of the millimeter wave radar 10. Run.

  The PCS ECU 40 determines, for example, whether the calculated ghost probability is equal to or higher than a predetermined threshold Pth1 (for example, 75%) for each update period of the millimeter wave radar 10, and is detected when the condition is satisfied. The determined object is determined to be a ghost. If the condition is not satisfied, it is determined that the detected object is not a ghost. As described above, the ghost probability of the object is maintained during the period in which the object is continuously detected by the millimeter wave radar 10, and the flowcharts of FIGS. Based on this, the ghost probability is also updated. Therefore, when the number of times of continuous detection by the millimeter wave radar 10 increases to some extent, it is determined that the detected object is a ghost.

  When the PCS ECU 40 determines that the detected object is a ghost, as described above, the collision avoidance braking control based on the detected object (the object determined to be a ghost) and the (collision of the object with the driver) Prohibiting driving assistance). In other words, the collision avoidance braking control and the driving assistance are executed based on an object determined not to be a ghost. Accordingly, it is possible to suppress the driver's uncomfortable feeling due to the collision avoidance braking control and the driving assistance based on the ghost target that is an object that does not exist.

  The parameters such as the initial value of the ghost probability, the ghost probability increase range, the ghost probability decrease range, and the predetermined threshold value Pth1 in FIGS. 3 and 4 described above and the predetermined threshold value Pth1 are set before the above-described collision avoidance braking control is executed. It may be set as appropriate so that it can be determined whether or not it is a ghost. For example, when it is desired to determine whether or not the number of times that the object is continuously detected by the millimeter wave radar 10 reaches a predetermined number Nmin, it is determined whether the ghost probability is Pth1 or more by the predetermined number Nmin. The above parameters should be set so that

  Next, the operation of the braking device 1 according to this embodiment will be described.

  The braking device 1 (PCS ECU 40) uses the relative distance Ds and the relative speed Vs of the object detected by the millimeter wave radar 10 and the relative distance Ds and the relative speed Vs calculated by the millimeter wave radar ECU 20, for example, in millimeters. Every time the wave radar 10 is updated, it is stored in a RAM or the like (buffered) in a historical manner. Further, the braking device 1 (PCS ECU 40) calculates the predicted distance Dest based on the relative distance Ds and the relative speed Vs of the object at the update time of the past millimeter wave radar 10 that has been buffered. Further, based on the comparison between the target speed Vtgt (= vehicle speed Vc + relative speed Vs) represented by the relationship between the vehicle speed Vc of the host vehicle and the relative speed Vs, and the relative distance Ds and the predicted distance Dest, the millimeter wave radar 10 It is determined whether or not the object detected by the above is a ghost. Then, predetermined braking control (the collision avoidance braking control or the like) is executed based on the object determined not to be a ghost. Specifically, whether or not the target speed Vtgt represented by the sum of the vehicle speed Vc of the host vehicle and the relative speed Vs is equal to or greater than a predetermined speed TH2, and the relative distance Ds of the millimeter wave radar 10 is greater than the predicted distance Dest. Based on whether or not the measurement error ΔDs is greater than or equal to, it may be determined whether or not the detected object is a ghost. Thus, based on the above-described ghost characteristics (2) and (3), by determining whether or not it is a ghost, a ghost generated by a reflector or the like that is continuously present on the lane side, It becomes possible to accurately determine as a ghost. Further, based on specific ghost characteristics, it is possible to suppress the determination of an actual object as a ghost. Therefore, the collision avoidance braking control based on the actual object detected by the millimeter wave radar 10 can be accurately executed, and the execution of the collision avoidance braking control based on the ghost target can be suppressed.

  Further, the braking device 1 (PCS ECU 40) may determine whether or not the object detected by the millimeter wave radar 10 is a ghost based on whether or not the relative distance Ds is equal to or less than the predetermined distance TH1. As described above, by adding (1) in addition to the ghost features (2) and (3), it is possible to more accurately determine whether or not the detected object is a ghost. Further, even if the object actually exists in the distance range that can be detected by the millimeter wave radar 10, the measurement error of the relative distance Ds and the relative velocity Vs becomes large for a distant object because the intensity of the reflected wave is weakened due to attenuation. The accuracy of the predicted distance Dest may be deteriorated. Therefore, there is a possibility that an actual object is determined to be a ghost. However, such an erroneous determination can be prevented by limiting the object to be determined as a ghost to an object whose relative distance Ds is equal to or less than the predetermined distance TH1 (an object at a short distance).

  Specifically, in the determination of whether or not a ghost, an index value (ghost probability) indicating the possibility that the object detected by the millimeter wave radar 10 is a ghost is calculated. Then, based on the relationship between the ghost probability and the predetermined threshold value Pth1 (whether the ghost probability is equal to or higher than the predetermined threshold value Pth1), it may be determined whether or not the detected object is a ghost. More specifically, the ghost probability of an object that is continuously detected may be updated every update period of the millimeter wave radar 10. When the target speed Vtgt (= vehicle speed Vc + relative speed Vs of the host vehicle) is equal to or higher than the predetermined speed TH2, and the relative speed Ds is larger than the predicted distance Dest by the measurement error ΔDs or more. In addition, the ghost probability may be increased. Further, when the target speed Vtgt (= vehicle speed Vc + relative speed Vs of the host vehicle) is equal to or higher than the predetermined speed TH2, and the relative speed Ds is larger than the predicted distance Dest by the measurement error ΔDs or more. In addition, when the relative distance Ds is equal to or less than the predetermined distance TH1, the ghost probability may be increased. Thus, for each update period of the millimeter wave radar 10, the ghost probability is updated while increasing the ghost probability when the conditions of the ghost characteristics (1) to (3) are satisfied, and the ghost probability and the predetermined threshold Pth1 are updated. It is possible to determine whether or not it is a ghost specifically. In addition, it is determined whether or not a ghost is generated before the above-described collision avoidance braking control or the like based on the detected object by appropriately setting an amount of ghost probability to be increased (a pulling range), an initial value of the ghost probability, or the like. It can be performed.

  Further, in the calculation of the predicted distance Dest, specifically, based on the relative speed of the predetermined number of times N with reference to the relative distance of the predetermined number N times before the update time of the current millimeter wave radar 10. It is good to calculate. Thereby, based on the ghost feature (2), when comparing the relative distance Ds and the predicted distance Dest, the influence of the measurement error of the millimeter wave radar 10 is eliminated, and whether or not the ghost is accurately determined. Can be determined. That is, when the relative speed Vs is small, it may not be possible to determine whether the relative speed Vs is the actual detected object relative speed or due to a measurement error. Thus, the difference between the relative speed Ds and the predicted distance Dest can be increased to such an extent that the influence of the measurement error can be eliminated.

[Second Embodiment]
Next, a second embodiment will be described.

  The braking device 1 in this embodiment is the same as that in the first embodiment in that the ghost probability of the detected object is calculated based on the above-described ghost features (1) to (3). However, the braking device 1 according to the present embodiment is different from the first embodiment in that the ghost probability is changed based on whether or not the object detected by the millimeter wave radar 10 is detected by the stereo camera 15. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and different portions will be mainly described.

  Since the structure of the braking device 1 in this embodiment is represented in FIG. 1 as in the first embodiment, the description thereof is omitted.

  Next, a method in which the braking apparatus 1 (PCS ECU 40) according to the present embodiment determines whether or not the detected object is a ghost will be specifically described.

  6 and 7 are flowcharts showing the operation of the braking device 1 (PCS ECU 40) according to the present embodiment. Specifically, it is a flowchart showing a process of calculating a ghost probability of the detected object by the braking device 1. 6 and 7 is executed every predetermined period, for example, every update period of the millimeter wave radar 10, from when the ignition switch of the vehicle is turned on until it is turned off.

  In the flowchart shown in FIG. 6, steps S201 to S212 and steps S216 to 217 are the same as steps S101 to S112 and steps S114 to S115 of FIG. 3 in the first embodiment. Description will be omitted. In the flowchart shown in FIG. 7, steps S220 to S225 and steps S229 to S230 are the same as steps S116 to S121 and steps S123 to 124 of FIG. 4 in the first embodiment. Description is omitted. The following description will focus on steps S213 to S215, steps S218 to S219, and steps S226 to S228 that are different from the first embodiment.

  3 and 4 of the first embodiment, the relative distance Ds, the relative speed Vs, the target speed Vtgt, the vehicle speed Vc, the predicted distance Dest, and the measurement error ΔDs are used. In the following description, as in the first embodiment, each speed (absolute speed, relative speed) is positive in the traveling direction of the host vehicle and negative in the direction toward the host vehicle. In the description of the flowcharts of FIGS. 6 and 7, an object detected by the millimeter wave radar 10 is simply referred to as “detected object”.

  Steps S206 to S217 in FIG. 6 are a flow for setting (calculating) a ghost probability for an object that is continuously detected by the millimeter wave radar 10, and the period (number of times) detected by the millimeter wave radar 10 is compared. The flow when the target is short (less) is shown.

  In step S210, it is determined whether or not the continuously detected object matches the above-described ghost features (1) and (3). Specifically, the relative distance Ds received from the millimeter wave radar ECU 20 is equal to or less than the predetermined distance TH1 (characteristic (1) described above), and the target speed Vtgt (= vehicle speed Vc + relative speed Vs) is the predetermined speed TH2. Whether it is the above (characteristic of (3) mentioned above) is determined. If the condition is satisfied, the process proceeds to step S211. If the condition is not satisfied, the process proceeds to step S213.

  Here, in the first embodiment, if the condition, that is, the condition related to the ghost feature is not satisfied, the possibility of existence increases, so the uniform ghost probability is reduced by 5% (step S113 in FIG. 3). However, in the present embodiment, the ghost probability reduction range is changed according to whether or not the object detected by the millimeter wave radar 10 is also detected by the stereo camera 15. That is, an image target (hereinafter referred to as a fusion image target) that can be fused with an object detected by the millimeter wave radar 10 in an object (image target) in an image captured by the stereo camera 15. ) Is changed depending on whether or not) is included. Hereinafter, a specific description will be given.

  In step S213, it is determined whether there is a fusion image target. If there is a fusion image target, since the object detected by the millimeter wave radar 10 is also detected by the stereo camera 15, the possibility that the object actually exists is further increased. Therefore, the process proceeds to step S 214, and the ghost probability is reduced by 5%. . On the other hand, if there is no fusion image target, the process proceeds to step S215, and the ghost probability is lowered by 2% while suppressing the decrease in the ghost probability as compared with the case where there is a fusion image target.

  Further, in the steps S226 to S228 in the flow (steps S218 to S230 in FIG. 7) for an object whose period (number of times) detected by the millimeter wave radar 10 is relatively long (large), the ghost probability is lowered by the same concept. Change the width.

  In step S223, it is determined whether or not the detected object matches the above-described ghost features (1) to (3). Specifically, the relative distance Ds received from the millimeter wave radar ECU 20 is equal to or less than the predetermined distance TH1 (characteristic (1) described above), and the target speed Vtgt (= vehicle speed Vc + relative speed Vs) is the predetermined speed TH2. It is determined whether or not the above (feature (3) described above) and the relative distance Ds is larger than the predicted distance Dest by the measurement error ΔDs of the millimeter wave radar 10 (feature (2) mentioned above). If the condition is satisfied, the process proceeds to step S223. If the condition is not satisfied, the process proceeds to step S226.

  In step S226, it is determined whether there is a fusion image target. If there is a fusion image target, since the object detected by the millimeter wave radar 10 is also detected by the stereo camera 15, the possibility that the object actually exists is further increased. Therefore, the process proceeds to step S 227 and the ghost probability is reduced by 10%. . On the other hand, if there is no fusion image target, the process proceeds to step S215, and the ghost probability is reduced by 5% while suppressing the ghost probability from being lowered compared to the case where the fusion image target is present.

  In this manner, the accuracy of the ghost probability can be further improved by changing the ghost probability reduction range according to whether or not the object detected by the millimeter wave radar 10 is also detected by the stereo camera 15.

  By the way, when the ghost probability has already been relatively high, if it is determined that there is a fusion image target, the ghost probability will be greatly reduced, and thus it may take unnecessary time until the ghost probability is determined. is there. As a result, before it is determined that the object is a ghost, there is a risk that the collision avoidance braking control based on the object that is the ghost or the driving assistance that informs the driver of the possibility of collision with the object may be executed first. There is a risk of discomfort. Therefore, when the ghost probability is relatively high, the fusion of the object (target information) detected by the millimeter wave radar 10 and the image target (target information) by the stereo camera 15 is not performed. (Fusion release). Hereinafter, a specific description will be given.

  In step S218 of FIG. 7, it is determined whether or not the ghost probability is smaller than a predetermined threshold value Pth2 (<Pth1). If the condition is satisfied, the process proceeds to step S220. When the condition is not satisfied, that is, when the ghost probability is relatively high and is equal to or greater than the predetermined threshold value Pth2, the process proceeds to step S219, where the object detected by the millimeter wave radar 10 and the object detected by the stereo camera 15 are fused. Is prohibited (fusion release). Thereby, in step S226, the determination condition is not satisfied, and the process proceeds to step S228. Therefore, it is possible to suppress a decrease in the ghost probability. Therefore, it is possible to suppress an increase in time until it is determined that the detected object is a ghost.

  Instead of steps S218 to S219, a determination step similar to step S218 may be provided between steps S223 and S226. In this case, if the determination condition of the step (whether the ghost probability is smaller than the predetermined threshold Pth2) is satisfied, the process proceeds to step S226 as it is, and the amount of decrease in the ghost probability is changed depending on whether there is a fusion image. It's okay. If the condition is not satisfied, the ghost probability is relatively high. Therefore, the process proceeds to step S228, and the ghost probability is preferably reduced. Thereby, the same effect as Steps S218 to S219 described above can be obtained. Further, processing similar to steps S218 to S219 may be set between step S207 and step S208 in FIG.

  In this way, the PCS ECU 40 executes the ghost probability calculation processing according to the flowcharts shown in FIGS. 6 and 7 described above for the detected object, for example, every update period of the millimeter wave radar 10.

  As in the first embodiment, the PCS ECU 40 determines, for example, whether the calculated ghost probability is equal to or higher than a predetermined threshold Pth1 (for example, 75%) for each update period of the millimeter wave radar 10, and If the condition is satisfied, it is determined that the detected object is a ghost. If the condition is not satisfied, it is determined that the detected object is not a ghost. As described above, during the period in which the object is continuously detected by the millimeter wave radar 10, the ghost probability of the object is maintained, and for each update period of the millimeter wave radar 10, based on the flowcharts of FIGS. The ghost probability is also updated. Therefore, when the number of times of continuous detection by the millimeter wave radar 10 increases to some extent, it is determined that the detected object is a ghost.

  When the PCS ECU 40 determines that the detected object is a ghost, the collision avoidance braking control based on the detected object (the object determined to be a ghost) and (to the driver) as in the first embodiment. Prohibiting driving assistance (notifying the possibility of collision with an object). Accordingly, it is possible to suppress the driver's uncomfortable feeling due to the collision avoidance braking control and the driving assistance based on the ghost target that is an object that does not exist.

  The parameters such as the initial value of the ghost probability, the ghost probability increase range, the ghost probability decrease range and the predetermined threshold value Pth1 in FIGS. 6 and 7 described above and the predetermined threshold value Pth1 are set as appropriate, as in the first embodiment. Good.

  Next, the operation of the braking device 1 according to this embodiment will be described. Note that operations similar to those of the first embodiment will be omitted, and operations unique to the present embodiment will be mainly described.

  The braking device 1 (PCS ECU 40) is based on whether the stereo camera 15 that detects an object ahead of the host vehicle has detected an object detected by the millimeter wave radar 10 based on a principle different from that of the millimeter wave radar 10. Then, it is determined whether or not the object detected by the millimeter wave radar 10 is a ghost. Specifically, when an object detected by the millimeter wave radar 10 is detected by the stereo camera 15 in the ghost probability calculation process, the ghost probability is reduced and the width is increased. In this way, by comparing with an object detected by other object detection means (stereo camera 15), it is possible to better prevent an actual object from being determined to be a ghost.

  Further, when the ghost probability is equal to or greater than the predetermined threshold Pth2, even if an object detected by the millimeter wave radar 10 is detected by the stereo camera 15, the ghost probability is not increased. As a result, the ghost probability is relatively high, and for an object that is highly likely to be determined to be a ghost, it is possible to suppress an increase in the time until it is determined to be a ghost unnecessarily, and collision avoidance braking control, etc. It can be determined whether or not it is a ghost before it is executed.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

1 Braking device 10 Millimeter wave radar (object detection means)
15 Stereo camera (other object detection means)
20 millimeter wave radar ECU (object detection means, relative distance calculation means, relative speed calculation means)
25 Stereo camera ECU (other object detection means)
30 Wheel speed sensor (speed detection means)
35 Yaw rate sensor 40 PCS ECU (storage means, determination means, control means)
50 Brake ECU (control means)
60 Brake actuator 70 Meter ECU
80 Combination meter 85 Notification sound generator

Claims (7)

Speed detecting means for detecting the absolute speed of the host vehicle;
Object detection means for detecting an object in front of the host vehicle and acquiring information related to the relative position of the object;
Based on the information acquired by the object detection means, a distance calculation means for calculating a distance from the host vehicle to the object;
A relative speed calculating means for calculating a relative speed of the object with respect to the host vehicle based on the information acquired by the object detecting means;
Storage means for storing the distance and the relative speed;
Prediction means for calculating a predicted distance as a predicted value of the distance at the certain time point based on the distance and the relative speed in the past from the certain time point stored in the storage means;
The object detection means based on the absolute speed of the object calculated from the absolute speed and the relative speed calculated by the relative speed calculation means, and a comparison between the predicted distance and the distance calculated by the distance calculation means Determining means for determining whether or not the object detected by the method is a ghost;
Control means for performing predetermined braking control based on an object determined not to be a ghost by the determination means,
Braking device. The determination means includes
Determining whether the object detected by the object detection means is a ghost based on whether the distance calculated by the distance calculation means is equal to or less than a predetermined distance;
The braking device according to claim 1. The determination means includes
An index value indicating the possibility that the object detected by the object detection means is a ghost is calculated, and whether or not the object detected by the object detection means is a ghost based on the relationship between the index value and a predetermined threshold value To determine,
The braking device according to claim 1 or 2. The determination means includes
The absolute speed of the object calculated as the sum of the absolute speed and the relative speed calculated by the relative speed calculation means is a predetermined speed or more, and the distance calculated by the distance calculation means is Increasing or decreasing the index value to a side where it is determined that the object detected by the object detection means is a ghost when greater than a predetermined distance than the predicted distance;
The braking device according to claim 3. The determination means includes
The absolute speed of the object calculated as the sum of the absolute speed and the relative speed calculated by the relative speed calculation means is a predetermined speed or more, and the distance calculated by the distance calculation means is The object detected by the object detection means is determined to be a ghost when the distance is greater than a predetermined distance by the predetermined distance and the distance calculated by the distance calculation means is less than or equal to the predetermined distance. Increase or decrease the indicator value to the side,
The braking device according to claim 3. Based on a principle different from that of the object detection means, it comprises an object detection means for detecting an object ahead of the host vehicle and acquiring information related to the relative position of the object with respect to the host vehicle,
The determination means includes
Determining whether the object detected by the object detection means is a ghost based on whether the object detected by the object detection means is detected by the other object detection means;
The braking device according to any one of claims 1 to 5. The object detection means includes
Detects objects ahead of the vehicle by transmitting electromagnetic waves and receiving reflected waves,
The other object detection means includes
The front of the host vehicle is imaged, and an object in front of the host vehicle is detected from the captured image.
The braking device according to claim 6.

Images