JP2019143977A - Determination system, sensor system, and detection method - Google Patents

Abstract

To enable the accuracy of determining the presence of a detection target to be improved.SOLUTION: An acquisition unit 4 acquires a received wave signal Sig1. The received wave signal Sig1 indicates the received wave intensity of a reflected wave W2 generated as a repeatedly transmitted detection wave W1 is reflected by an object 7. An output unit 6 outputs the determination result of the determination unit 5. A determination unit 5 determines that a detection target exists when a first detection count reaches a first intended count and a second detection count is greater than or equal to a second intended count. The first detection count is the number of times a received wave signal Sig1 that indicates received wave intensity exceeding a first threshold is detected. The second detection count is the number of times a received wave signal Sig1 that indicates received wave intensity exceeding a second threshold is detected in the received wave signal Sig1 having indicated received wave intensity exceeding the first threshold.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a determination system, a sensor system, and a determination method. More specifically, the present disclosure relates to a determination system that determines whether a detection target exists, a sensor system that includes the determination system, and a determination method that determines whether a detection target exists.

  As a conventional example, an obstacle detection device for a vehicle described in Patent Document 1 is illustrated. The vehicle obstacle detection device described in Patent Literature 1 includes a signal transmission unit, a signal reception unit, and an obstacle determination unit. The signal transmission means transmits a predetermined signal around the vehicle. The signal receiving means receives the reflected signal of the predetermined signal from the signal transmitting means. The obstacle determining means determines that there is an obstacle around the vehicle when the reflected signal received by the signal receiving means satisfies a predetermined condition. More specifically, the obstacle determination unit is configured such that the number of continuous receptions of the reflected signal in the signal receiving unit is equal to or greater than a predetermined number, or the reception level of the reflected signal received by the signal receiving unit is equal to or greater than a predetermined threshold If there is an obstacle around the vehicle.

JP 2008-058234 A

  However, in the vehicle obstacle detection device described in Patent Document 1, when the reflected signal from an object other than the obstacle (detection target) is received by the signal reception means, the obstacle determination means is said to have an obstacle. There is a possibility of making a wrong judgment. In the vehicle obstacle detection device described in Patent Document 1, for example, the reception level of the reflected signal from the obstacle is temporarily reduced to a value smaller than a predetermined threshold due to disturbance due to wind fluctuation around the obstacle. May be reduced. At this time, the obstacle determination means may determine an erroneous determination that there is no obstacle.

  An object of the present disclosure is to provide a determination system, a sensor system, and a determination method that can improve the determination accuracy of the presence or absence of a detection target.

  In order to solve the above problem, a determination system according to an aspect of the present disclosure includes an acquisition unit, a determination unit, and an output unit. The acquisition unit acquires a received signal. The received signal indicates the received intensity of the reflected wave that is generated when the detection wave that is repeatedly transmitted is reflected by the object. A determination part determines the presence or absence of the object applicable to a detection target among objects based on the received wave signal acquired in the acquisition part. The output unit outputs the determination result of the determination unit. The determination unit determines that the detection target exists when the first detection number reaches the first target number and the second detection number is equal to or greater than the second target number. The first number of detections is the number of detections of the received signal indicating the received signal intensity exceeding the first threshold. The second number of detections is the number of detections of the received signal that indicates the received intensity exceeding the second threshold in the received signal that indicates the received intensity exceeding the first threshold. The second threshold is greater than the first threshold. The second target number is less than the first target number.

  A sensor system according to an aspect of the present disclosure includes a determination system and a sensor. The sensor transmits the detection wave, converts the reflected wave into a reception signal, and outputs the received signal to the acquisition unit.

  The determination method according to an aspect of the present disclosure includes an acquisition step, a determination step, and an output step. In the acquisition step, a received signal is acquired. The received signal indicates the received intensity of the reflected wave that is generated when the detection wave that is repeatedly transmitted is reflected by the object. In the determination step, the presence / absence of an object corresponding to the detection target among the objects is determined based on the received wave signal acquired in the acquisition step. In the output step, the determination result in the determination step is output. In the determination step, when the first number of detections reaches the first target number and the second number of detections is equal to or greater than the second target number, it is determined that the detection target exists. The first number of detections is the number of detections of the received signal indicating the received signal intensity exceeding the first threshold. The second number of detections is the number of detections of the received signal that indicates the received intensity exceeding the second threshold in the received signal that indicates the received intensity exceeding the first threshold. The second threshold is greater than the first threshold. The second target number is less than the first target number.

  The determination system, the sensor system, and the determination method according to an aspect of the present disclosure can improve the determination accuracy of the presence / absence of a detection target.

FIG. 1 is a block diagram of a sensor system according to the first embodiment. FIG. 2 is a flowchart showing an operation example of the sensor system. 3A to 3C are plan views of a vehicle including the sensor system described above. 4A to 4C are graphs showing the relationship between the distance between the wave receiving unit and the object and the crest value and the measurement result of the crest value in the above sensor system. FIG. 5 is a graph showing the relationship between the distance between the wave receiving unit and the object and the peak value in the sensor system according to the second embodiment.

  Hereinafter, a determination system, a sensor system, and a determination method according to embodiments will be described with reference to the drawings. However, each embodiment described below is only a part of various embodiments of the present disclosure. Each embodiment described below can be variously modified according to the design or the like as long as the object of the present disclosure can be achieved.

(Embodiment 1)
(Configuration of sensor system)
As shown in FIG. 1, the sensor system 1 of this embodiment includes a sensor 2 and a determination system 3. The sensor 2 has a plurality (two in FIG. 1) of sensor units 20. The sensor system 1 is provided in a vehicle 10 (see FIG. 3A) such as an automobile, for example. The determination system 3 includes an acquisition unit 4, a determination unit 5, and an output unit 6. The determination system 3 further includes a first counter 51, a second counter 52, and a storage unit 53.

  Each of the plurality of sensor units 20 includes a wave transmission unit 21 and a wave reception unit 22. Each of the plurality of wave transmitting units 21 repeatedly transmits the detection wave W1. More specifically, the transmission unit 21 transmits the detection wave W1 intermittently (for example, at intervals of 200 ms). The detection wave W1 is, for example, an ultrasonic wave. Each of the plurality of wave receiving units 22 receives a reflected wave W2 generated by the detection wave W1 being reflected by the object 7. Thereby, the sensor system 1 can detect the object 7 present around the vehicle 10. The wave receiver 22 converts the reflected wave W2 into a received signal Sig1 and outputs it to the acquisition unit 4. The received wave signal Sig1 is a signal indicating the received wave intensity (voltage value) of the reflected wave W2 measured by the wave receiving unit 22. More specifically, the received signal Sig1 is a signal obtained by converting the reflected wave W2 into an electric signal. The received signal Sig1 has information on the waveform of the reflected wave W2. The detection wave W1 is not limited to an ultrasonic wave, and may be a radio wave such as a millimeter wave radar.

  The sensor system 1 is configured not to detect an object 7 other than the detection target while detecting the object 7 corresponding to the detection target such as an obstacle. In the following description, among the objects 7, the object 7 corresponding to the detection target may be referred to as “detection target”, and the object 7 other than the detection target may be referred to as “non-target object”.

  In the present embodiment, the detection target is, for example, an obstacle, and more specifically, a vehicle other than the vehicle 10, a wall, a fence, and a pole such as a utility pole. An example of the non-target object is an object having a smaller size than the detection target (for example, an object having a height of 10 cm or less with respect to the road surface), for example, an object that forms a step with respect to the road surface. A specific example of the non-target object is a curbstone.

  The acquisition unit 4 acquires a plurality of reception signals Sig1 output from the plurality of reception units 22. The acquisition unit 4 includes, for example, an analog-digital conversion circuit, converts the received signal Sig1 from an analog signal to a digital signal, and outputs the converted signal to the determination unit 5. The determination unit 5 determines the presence or absence of the detection target based on the plurality of received signals Sig1 acquired by the acquisition unit 4. The output unit 6 outputs the determination result of the determination unit 5.

  More specifically, the output unit 6 outputs the determination result of the determination unit 5 to the vehicle control circuit 8 by a signal Sig2 (electric signal). The vehicle control circuit 8 is provided as a configuration outside the sensor system 1. Each of the sensor system 1 and the vehicle control circuit 8 is a partial configuration of an ECU (Electronic Control Unit) of the vehicle 10 (see FIG. 3A). The vehicle control circuit 8 controls at least one of the buzzer provided in the vehicle 10 and the brake of the vehicle 10 according to the determination result of the determination unit 5. For example, when the determination unit 5 determines that a detection target exists, the vehicle control circuit 8 notifies the driver of the presence of the detection target by controlling a buzzer provided in the vehicle 10 to sound a warning sound. To do. In addition, the vehicle control circuit 8 may control the brake of the vehicle 10 to operate the brake instead of controlling the buzzer to sound the warning sound, or may control the buzzer to sound the warning sound. In addition to the above, the brake of the vehicle 10 may be controlled to operate the brake.

  In the present embodiment, the peak value H1 (see FIG. 4A) of the reflected wave W2 received by the wave receiving unit 22 is handled as the received wave intensity of the reflected wave W2. The received signal Sig1 acquired by the acquisition unit 4 has information on the waveform of the reflected wave W2, including information on the peak value H1 of the reflected wave W2. The determination unit 5 compares the peak value H1 of the reflected wave W2 indicated by the received signal Sig1 with the first threshold value V1 (see FIG. 4A), thereby receiving the received peak value H1 that exceeds the first threshold value V1. The signal Sig1 is detected. Further, the determination unit 5 compares the peak value H1 of the reflected wave W2 indicated by the received signal Sig1 with a second threshold value V2 (see FIG. 4A), thereby indicating a peak value H1 that exceeds the second threshold value V2. A received signal Sig1 is detected. Furthermore, the determination unit 5 determines the presence / absence of a detection target based on a result of comparing the peak value H1 with the first threshold value V1 and the second threshold value V2. The first threshold value V1 and the second threshold value V2 are determined in advance and are stored in the storage unit 53. Hereinafter, operation | movement of the sensor system 1 until the determination part 5 determines the presence or absence of a detection target is demonstrated in detail. Here, in order to simplify the description, it is assumed that the sensor 2 has only one sensor unit 20.

  In the sensor system 1, the transmission unit 21 of the sensor unit 20 transmits the detection wave W1, and the reception unit 22 of the sensor unit 20 receives the reflected wave W2 that is generated when the detection wave W1 is reflected by the object 7. The process is repeated.

  When the transmitting unit 21 transmits the detection wave W1 and the receiving unit 22 receives the reflected wave W2, the receiving unit 22 converts the reflected wave W2 into a received signal Sig1 and outputs it to the acquiring unit 4. That is, as shown in FIG. 2, the acquisition unit 4 acquires the received signal Sig1 (step S1: acquisition step).

  The determination unit 5 determines whether there is a detection target. The determination unit 5 determines whether the peak value H1 (see FIG. 4A) of the reflected wave W2 indicated by the received signal Sig1 acquired by the acquisition unit 4 exceeds the first threshold value V1 (see FIG. 4A). The count number (first detection count) of the counter 51 is increased by one. The first number of detections corresponds to the number of detections by the determination unit 5 of the received signal Sig1 indicating the peak value H1 exceeding the first threshold value V1. In addition, in the received signal Sig1 indicating the peak value H1 exceeding the first threshold value V1, the determination unit 5 outputs the second value when the peak value H1 exceeds the second threshold value V2 (see FIG. 4A). The count number (second detection count) of the counter 52 is increased by one. In other words, when the peak value H1 of the reflected wave W2 indicated by the received signal Sig1 detected as exceeding the first threshold value V1 by the determination unit 5 exceeds the second threshold value V2, the determination unit 5 The count number (second detection count) of the second counter 52 is increased by one. The second number of detections corresponds to the number of detections by the determination unit 5 of the received signal Sig1 indicating the peak value H1 exceeding the second threshold value V2. On the other hand, when the peak value H1 of the reflected wave W2 is equal to or less than the first threshold value V1, the determination unit 5 resets the count numbers of the first counter 51 and the second counter 52 to zero.

  As will be described later, when the object 7 does not continue to exist in the certain range RA1 (see FIG. 3A), the determination unit 5 counts the counts of the first counter 51 and the second counter 52. Does not increase.

  As shown in FIG. 2, while the process in which the sensor unit 20 transmits the detection wave W1 and receives the reflected wave W2 is repeated, the peak value H1 is continuously set to the first threshold value in three or more processes. Assume that V1 is exceeded. At this time, the count number (first detection number) of the first counter 51 reaches three, which is the first target number (step S2: Yes). Further, the count number (first detection number) of the first counter 51 reaches the first target number (three times), and at that time, the count number (second detection number) of the second counter 52 is the second number. If it is equal to or more than the target number of times (one time) (step S3: Yes), the determination unit 5 determines that there is a detection target (step S4). The first target number and the second target number are determined in advance and stored in the storage unit 53.

  On the other hand, when the count number (first detection number) of the first counter 51 does not reach the first target number (three times) (step S2: No), the determination unit 5 has a detection target. It is determined not to be performed (step S5). Further, the count number (first detection number) of the first counter 51 reaches the first target number (three times) (step S2: Yes). At that time, the count number (second detection) of the second counter 52 is reached. When the number of times is less than the second target number of times (one time) (step S3: No), the determination unit 5 determines that there is no detection target (step S5).

  Steps S2 to S5 are determination steps in which the determination unit 5 determines whether or not a detection target exists.

  After step S4 or step S5, the output unit 6 outputs the determination result of the determination unit 5 (step S6: output step). The determination method according to the present embodiment includes the above-described acquisition step, determination step, and output step.

  In this way, the determination unit 5 determines that the first detection count reaches the first target count of 3 and the second detection count is 1 or more, which is the second target count. Is determined to exist.

  More specifically, the determination unit 5 continuously detects the received signal Sig1 indicating the peak value H1 exceeding the first threshold value V1 for the first target number of times (three times), and the second detection number is If it is equal to or greater than the second target number of times (one time), the determination unit 5 determines that a detection target exists. In short, the determination unit 5 determines that the detection target exists when the following first condition and second condition are satisfied. The first condition is that when the process in which the sensor unit 20 transmits the detection wave W1 and receives the reflected wave W2 is repeated, the process continues for the first target number of times (three times) in the above process. The peak value H1 is larger than the first threshold value V1. The second condition is that the first target number of times when the peak value H1 of the reflected wave W2 is greater than the first threshold value V1 in the first target number of times (three times) of the above process. The crest value H1 is larger than the second threshold value V2 in the above-described process of 2 or more target times (one time).

  When a detection target exists around the vehicle 10 and a reflected wave W2 is generated at the detection target, the peak value H1 of the reflected wave W2 generated at the detection target is likely to exceed the second threshold value V2. However, when the detection target is, for example, a wall, depending on the distance between the wall and the sensor unit 20, a reflected wave W2 that directly reaches the wave receiving unit 22 from the wall and a road surface of the reflected wave W2 that occurs on the wall, etc. There is a possibility that the peak value H1 of the reflected wave W2 received by the wave receiving unit 22 may decrease due to the interference with the reflected wave W2 that reaches the wave receiving unit 22 after being reflected at. Further, the peak value H1 of the reflected wave W2 may temporarily decrease due to disturbance caused by fluctuations in wind around the detection target.

  In the sensor system 1 of the present embodiment, the determination unit 5 determines that the first number of detections reaches the first target number (3 times), and at that time, the second number of detections is equal to or greater than the second target number (1). If there is, it is determined that a detection target exists. That is, the determination unit 5 determines that the number of times the peak value H1 has exceeded the first threshold value V1 has reached the first target number of times (three times), and the number of times that the peak value H1 has exceeded the second threshold value V2 If it is equal to or greater than the second target number (one time), it is determined that a detection target exists. Therefore, even if the peak value H1 of the reflected wave W2 temporarily decreases to a value greater than the first threshold value V1 and less than or equal to the second threshold value V2, the determination unit 5 may determine that a detection target exists. it can.

  By the way, as shown in FIG. 1, the sensor 2 actually has a plurality of sensor units 20. Hereinafter, it is assumed that the sensor 2 includes a plurality of sensor units 20. When the sensor 2 has a plurality of sensor units 20, the first counter 51 has a peak value of the reflected wave W2 indicated by the received signal Sig1 output from the sensor unit 20 for each sensor unit 20. What is necessary is just to count the frequency | count (1st detection frequency) that H1 exceeded 1st threshold value V1. In addition, the second counter 52 counts the number of times (second value) that the peak value H1 of the reflected wave W2 indicated by the received signal Sig1 output from the sensor unit 20 exceeds the second threshold value V2 for each sensor unit 20. The number of detections) may be counted. For example, in at least one sensor unit 20 among the plurality of sensor units 20, the first detection number reaches the first target number (three times), and at that time, the second detection number is the second target number ( If the condition that it is equal to or greater than (one time) is satisfied, the determination unit 5 may determine that the detection target exists.

  The sensor 2 further includes a control circuit 23 that controls the plurality of sensor units 20. The control circuit 23 shifts the phase of the detection wave W <b> 1 transmitted by each of the transmission units 21 of the plurality of sensor units 20 from each other and transmits the detection wave W <b> 1. Thereby, the detection wave W1 transmitted by the transmission unit 21 of some of the plurality of sensor units 20 and the detection wave W1 transmitted by the transmission unit 21 of another sensor unit 20 are mutually connected. The possibility of interference and the possibility that a plurality of reflected waves W2 interfere with each other are reduced.

  The determination system 3 further includes a position detection unit 54 that detects the position of the object 7. The position detection unit 54 also functions as a distance measurement unit that measures the distance L1 (see FIG. 3A) between the wave receiving unit 22 of each sensor unit 20 and the object 7.

  The position detection unit 54 receives the wave at each sensor unit 20 based on the time elapsed between the transmission timing of the detection wave W1 at each sensor unit 20 and the reception timing of the reflected wave W2 at each sensor unit 20. A distance L1 (see FIG. 3A) between the unit 22 and the object 7 is measured. Further, the position detection unit 54 includes the distance L1 between the wave receiving unit 22 and the object 7 in each sensor unit 20, the vehicle speed of the vehicle 10 acquired by the speedometer of the vehicle 10 (see FIG. 3A), and the vehicle 10 The position of the object 7 is detected based on the steering angle of the vehicle 10 acquired by the steering angle sensor.

  As shown in FIG. 3A, the plurality of sensor units 20 are arranged in a line in the front portion of the vehicle 10. The plurality of sensor units 20 are attached to a bumper of the vehicle 10. Although two sensor units 20 are illustrated in FIG. 3A, actually three or more sensor units 20 are provided side by side in one direction D <b> 1 of the vehicle 10. One direction D1 in which the plurality of sensor units 20 are arranged is a direction along the horizontal direction when the vehicle 10 is on a horizontal road surface, and is a direction orthogonal to the front-rear direction D2 of the vehicle 10. The front-rear direction D2 of the vehicle 10 is a direction along the straight traveling direction of the vehicle 10.

  In each of the plurality of sensor units 20, the process is repeated in which the transmission unit 21 transmits the detection wave W <b> 1 and the reception unit 22 receives the reflected wave W <b> 2 that is generated when the detection wave W <b> 1 is reflected by the object 7. It is. In the following description, the detection waves W1 in the Nth (N is a natural number), N + 1th, and N + 2th processes in each sensor unit 20 are referred to as detection waves W1 [N], W1 [N + 1], and W1 [N + 2], respectively. . In the following description, the reflected waves W2 in the Nth, N + 1th, and N + 2th processes in each sensor unit 20 are referred to as reflected waves W2 [N], W2 [N + 1], and W2 [N + 2], respectively. In the following description, it is assumed that the above processes are executed while the vehicle 10 moves so as to approach the object 7. When the positional relationship between the vehicle 10 and the object 7 is as shown in FIG. 3A, the Nth process is executed, and when it is as shown in FIG. 3B, the N + 1th process is executed, as shown in FIG. 3C. It is assumed that the N + 2th process is executed. As the vehicle 10 or the object 7 moves, the distance L1 changes. In the present embodiment, the description will be made on the assumption that the vehicle 10 moves while the object 7 does not move.

  In the N-th process, each of the plurality of sensor units 20 receives one sensor unit 20 and at least one sensor unit 20 adjacent to the sensor unit 20 (here, one sensor unit 20). It is assumed that the peak value H1 of the reflected wave W2 exceeds the first threshold value V1. In this case, the position detection unit 54 determines whether each of the two sensor units 20 transmits the detection wave W1 [N] and receives the reflected wave W2 [N]. A distance L1 between the wave receiving unit 22 of the sensor unit 20 and the object 7 is calculated. Furthermore, the position detection unit 54 uses the trigonometric method based on the mutual positional relationship between the two sensor units 20 and the distance L1 between the wave receiving unit 22 of each sensor unit 20 and the object 7. The position of the object 7 with respect to is obtained. The position of the object 7 with respect to the vehicle 10 is obtained, for example, as the coordinates of the object 7 when the origin is taken at the position where one specific sensor unit 20 is present among the plurality of sensor units 20.

  3A to 3C, the two sensor units 20 are distinguished from each other and are also indicated as sensor units 20a and 20b, respectively. 3A to 3C, the two sensor units 20 are distinguished from each other, and the distance L1 between the wave receiving unit 22 of each sensor unit 20 and the object 7 is also expressed as distances L1a and L1b, respectively.

  As shown in FIG. 3B, in the N + 1th process, when the detection wave W1 [N + 1] is transmitted and the reflected wave W2 [N + 1] is received, the position detection unit 54 uses the trigonometry to detect the vehicle 10 The position of the object 7 is obtained again. Further, the position detection unit 54 of the vehicle 10 from the time of FIG. 3A (the time of receiving the reflected wave W2 [N]) to the time of FIG. 3B (the time of receiving the reflected wave W2 [N + 1]). The movement amount and the movement direction are obtained based on the vehicle speed and the steering angle of the vehicle 10. The movement amount and the movement direction obtained at this time are referred to as an estimated movement amount M1 and an estimated movement direction, respectively. Between the time point in FIG. 3A and the time point in FIG. 3B, the estimated movement direction is substantially parallel to the front-rear direction D <b> 2 of the vehicle 10. The position detection unit 54 moves from the position of the object 7 obtained by trigonometry at the time of FIG. 3A to the estimated movement direction opposite to the traveling direction of the vehicle 10 by the estimated movement amount M1 in FIG. 3B. The position of the object 7 with respect to the vehicle 10 at the time is estimated.

  The position detection unit 54 represents the position of the object 7 at the time of FIG. 3B estimated based on the position of the object 7 obtained by trigonometry at the time of FIG. 3A, the estimated movement amount M1, and the estimated movement direction. The position of the object 7 obtained by trigonometry at the time point 3B is compared. The position detection unit 54 uses this comparison result to detect whether or not the object 7 is continuously present in the certain range RA1 from the time point of FIG. 3A to the time point of FIG. 3B. The certain range RA1 is a range that does not change even when the vehicle 10 moves, and is a range defined on the road surface, for example. The certain range RA1 is a virtual area set by the position detection unit 54 around the position of the object 7 obtained by the triangulation method by the position detection unit 54 at the time of FIG. 3A. Specifically, the position detector 54 estimates the object at the time of FIG. 3B estimated based on the estimated movement amount M1 of the vehicle 10, the estimated movement direction, and the position of the object 7 obtained by trigonometry at the time of FIG. 3A. When the distance between the position 7 and the position of the object 7 obtained by trigonometry at the time of FIG. 3B is shorter than a predetermined distance, it is detected that the object 7 is continuously present in the certain range RA1.

  When the position detection unit 54 detects that the object 7 is continuously present in the certain range RA1, the determination unit 5 detects the received signal Sig1 indicating the peak value H1 exceeding the first threshold value V1. The count number by the first counter 51 (the count number of the first detection count) is increased. At this time, when the received signal Sig1 indicating the peak value H1 exceeding the second threshold value V2 is detected, the determination unit 5 increases the count number (the count number of the second detection count) by the second counter 52. .

  When the position detection unit 54 does not detect that the object 7 is continuously present in the certain range RA1, the determination unit 5 can detect the received signal Sig1 indicating the peak value H1 exceeding the first threshold value V1. The number of counts by the first counter 51 (the number of counts of the first detection count) is not increased. At this time, even if the received signal Sig1 indicating the peak value H1 exceeding the second threshold value V2 is detected, the determination unit 5 determines the count number (count number of the second detection count) by the second counter 52. Do not increase.

  Next, FIGS. 4A to 4C illustrate the measured value by the position detection unit 54 of the distance L1 between the wave receiving unit 22 of one sensor unit 20 and the object 7 among the plurality of sensor units 20, and the sensor unit 20. The relationship with the measured value of the peak value H1 of the reflected wave W2 in FIG.

  4A to 4C, the first threshold value V1 and the second threshold value V2 are different values depending on the distance L1 between the wave receiving unit 22 and the object 7 measured by the position detection unit 54. is there. The second threshold value V <b> 2 is a threshold value that is set for detecting a detection target in the object 7. More specifically, the second threshold value V2 is a value of the reflected wave W2 that is generated when the detection wave W1 is reflected by the detection target (the object 7 that is an obstacle of the vehicle 10) existing in a predetermined area in front of the vehicle 10. The value is smaller than the received wave intensity in the wave receiving unit 22. The first threshold value V1 is a threshold value that is smaller than the second threshold value V2. The first threshold value V1 is set to a threshold value that can detect an object 7 that includes a non-target object such as a curb (an object 7 that forms a step with respect to a road surface). More specifically, the first threshold value V <b> 1 is a value smaller than the received wave intensity at the wave receiving unit 22 of the reflected wave W <b> 2 that is generated when the detected wave W <b> 1 is reflected by an untargeted object in front of the vehicle 10.

  The first threshold value V1 monotonously decreases as the distance L1 between the wave receiving unit 22 and the object 7 increases.

  In FIG. 4A, the first distance threshold Th1 and the second distance threshold Th2 are illustrated on the horizontal axis indicating the distance L1. The second distance threshold Th2 is smaller than the first distance threshold Th1.

  The second threshold value V2 when the distance L1 is shorter than the first distance threshold value Th1 is smaller than the second threshold value V2 when the distance L1 is the first distance threshold value Th1. More specifically, when the distance L1 is shorter than the first distance threshold Th1 and equal to or greater than the second distance threshold Th2, the second threshold V2 decreases as the distance L1 decreases. When the distance L1 is shorter than the second distance threshold Th2, the second threshold V2 is substantially equal to the first threshold V1 and is a constant value.

  In the range where the distance L1 is equal to or greater than the first distance threshold Th1, the second threshold V2 is a constant value even if the distance L1 becomes longer for a while. When the distance L1 becomes further longer, the second becomes longer as the distance L1 becomes longer. The threshold value V2 of becomes smaller.

  The difference between the first threshold value V1 and the second threshold value V2 is minimized when the distance L1 is shorter than the second distance threshold value Th2, and is maximized when the distance L1 is the first distance threshold value Th1.

  In the transmission unit 21 of each sensor unit 20, the detection wave W <b> 1 is transmitted along the horizontal direction, for example, and spreads in a conical shape having a vertex on the transmission unit 21 side. The detection wave W <b> 1 spreads farther than in the vicinity of the sensor unit 20. Therefore, the intensity of the detection wave W <b> 1 in the vicinity of the sensor unit 20 and deviated from the front surface of the sensor unit 20 (a position facing the sensor unit 20 in the horizontal direction) is smaller than that far from the sensor unit 20. Sometimes. Therefore, even if there is an object 7 (hereinafter referred to as a small object) that is not a detection target but a size smaller than the detection target in the vicinity of the sensor unit 20, the intensity of the detection wave W1 that has reached the small object is: It may be smaller than the intensity of the detection wave W1 that reaches the detection target. Therefore, the received intensity (crest value H1) of the reflected wave W2 from the small object at the receiving unit 22 is compared with the received intensity (crest value) of the reflected wave W2 from the detection target at the receiving unit 22. Sometimes it is small.

  Therefore, as shown in FIG. 4A, the second threshold V2 when the distance L1 between the wave receiver 22 and the object 7 is shorter than the second distance threshold Th2, and the distance L1 is the first distance threshold Th1. Even if it is smaller than the second threshold value V2 at this time, there is a low possibility that the peak value H1 of the reflected wave W2 generated by the small object will exceed the second threshold value V2. Therefore, even if there is a small object that is not a detection target in the vicinity of the sensor unit 20, there is a low possibility that the determination unit 5 erroneously determines that the detection target exists. On the other hand, the second threshold value V2 when the distance L1 is shorter than the second distance threshold value Th2 is smaller than the second threshold value V2 when the distance L1 is the first distance threshold value Th1. When the detection target exists in the vicinity, the determination unit 5 can more reliably determine that the detection target exists.

  The execution subject of the determination system 3, the sensor system 1, and the determination method in the present disclosure includes a computer system. The computer system has one or more computers. The computer system mainly includes a processor and a memory as hardware. When the processor executes the program recorded in the memory of the computer system, a function as an execution subject of the determination system 3, the sensor system 1, and the determination method in the present disclosure is realized. The program may be recorded in advance in the memory of the computer system, but may be provided through an electric communication line, or a non-temporary program such as a memory card, optical disk, or hard disk drive (magnetic disk) that can be read by the computer system. And may be provided by being recorded on a typical recording medium. A processor of a computer system includes one or more electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). The plurality of electronic circuits may be integrated on one chip, or may be distributed on the plurality of chips. The plurality of chips may be integrated into one device, or may be distributed and provided in a plurality of devices.

(Sensor system operation)
Next, the operation in which the sensor system 1 determines whether or not there is a detection target will be described. In the following description, it is assumed that the object 7 (detection target or non-target object) continuously exists in the certain range RA1 during the operation of the sensor system 1.

  4A to 4C illustrate the distance L1 between the wave receiving unit 22 of one sensor unit 20 and the object 7 among the plurality of sensor units 20, and the measured value of the peak value H1 of the reflected wave W2 in the sensor unit 20. Shows the relationship. 4A to 4C, each point on a plurality of pulses (for example, three pulses P1 to P3 in FIG. 4A) is a measured value of the peak value H1. The peak value H1 shown in FIGS. 4A to 4C is a value measured while the vehicle 10 moves so as to approach the object 7 as shown in FIGS. 3A to 3C. In the detection wave W1 and the reflected wave W2, the intensity decreases as the distance travels longer, and therefore the pulse height value H1 tends to decrease as the pulse has a longer distance L1.

  FIG. 4A shows a measurement result of the peak value H1 when a detection target exists around the vehicle 10 and a reflected wave W2 is generated in the detection target. As described above, the sensor unit 20 repeats the process of transmitting the detection wave W1 and receiving the reflected wave W2. Each of the pulses P1 to P3 corresponds to the reflected wave W2 in the N, N + 1, N + 2th process. In the pulse P2, the peak value H1 is small due to interference or disturbance of the reflected wave W2.

  The peak value H1 of the reflected wave W2 generated when the detection wave W1 is reflected by the detection target exceeds the first threshold value V1 and the second threshold value V2 in the pulse P1 and the pulse P3, and exceeds the first threshold value V1 in the pulse P2. It became below 2nd threshold value V2. Therefore, the first number of detections, which is the number of detections by the determination unit 5 of the received signal Sig1 indicating the peak value H1 exceeding the first threshold value V1, reaches the first target number (three times). At that time, the second number of detections, which is the number of detections by the determination unit 5 of the received signal Sig1 indicating the peak value H1 exceeding the second threshold V2, is two times equal to or greater than the second target number (one time). Become. Therefore, the determination unit 5 determines that there is a detection target.

  Thus, even when the detection target exists around the vehicle 10 and the reflected wave W2 is generated in the detection target, even if the peak value H1 is temporarily reduced due to interference or disturbance of the reflected wave W2, The determination unit 5 can determine that a detection target exists.

  FIG. 4B shows another measurement result of the peak value H1 when a detection target exists around the vehicle 10 and a reflected wave W2 is generated in the detection target. Each of the pulses P4 to P8 corresponds to the reflected wave W2 in the N, N + 1, N + 2, N + 3, and N + 4th process, in which the process of transmitting the detection wave W1 and receiving the reflected wave W2 is repeated. .

  The peak value H1 of the reflected wave W2 generated when the detection wave W1 is reflected by the detection target exceeds the first threshold value V1 in the pulse P4, and is equal to or less than the first threshold value V1 in the pulse P5. Therefore, when the reflected wave W2 corresponding to the pulse P5 is detected by the determination unit 5, the first number of detections is reset to zero. At this point, the determination unit 5 determines that there is no detection target.

  Thereafter, the peak value H1 exceeded the first threshold value V1 in the pulses P6 and P7 and became equal to or less than the second threshold value V2, and exceeded the first threshold value V1 and the second threshold value V2 in the pulse P8. Therefore, the first detection number reaches the first target number (three times). At that time, the second detection number is one time which is equal to or more than the second target number (one time). Therefore, the determination unit 5 determines that there is a detection target.

  FIG. 4C shows a measurement result of the peak value H1 when a non-target object (for example, a curb) exists around the vehicle 10 and a reflected wave W2 is generated in the non-target object. Each of the pulses P9 to P11 corresponds to the reflected wave W2 in the N, N + 1, N + 2th process, in which the process of transmitting the detection wave W1 and receiving the reflected wave W2 is repeated.

  The peak value H1 of the reflected wave W2 that is generated when the detection wave W1 is reflected by the detection target exceeds the first threshold value V1 in the pulses P9 to P11 and is equal to or less than the second threshold value V2. Therefore, the first detection number reaches the first target number (three times). At that time, the second number of detections is 0, which is less than the second target number (1). Therefore, the determination unit 5 determines that there is no detection target.

(Modification of Embodiment 1)
Next, modifications of the first embodiment are listed. The following modifications may be implemented in combination as appropriate.

  In the first embodiment, the first threshold value V1 and the second threshold value V2 are stored in the storage unit 53 of the determination system 3. Thus, the first threshold value V1 and the second threshold value V2 may be stored in the configuration of the determination system 3 (or sensor system 1). Alternatively, the first threshold value V1 and the second threshold value V2 may be stored in a configuration outside the determination system 3 (or the sensor system 1). Further, the first threshold value V1 and the second threshold value V2 may be stored in different configurations. For example, the sensor 2 may include a storage unit, the first threshold value V1 may be stored in the storage unit included in the sensor 2, and the second threshold value V2 may be stored in the storage unit 53 of the determination system 3. .

  Further, the determination unit 5 may determine the presence / absence of the detection target by using the effective value or the average value as the received wave intensity of the reflected wave W2 instead of the peak value H1 of the reflected wave W2. Or the determination part 5 may determine the presence or absence of a detection target using the received wave intensity itself of the reflected wave W2.

  Further, the determination unit 5 may realize some functions of the position detection unit 54. For example, among the functions of the position detection unit 54, the determination unit 5 realizes a function of detecting whether or not the object 7 is continuously present in the certain range RA <b> 1 based on the vehicle speed and the steering angle of the vehicle 10. May be. At this time, information on the vehicle speed and the steering angle of the vehicle 10 may be input to the determination unit 5. Alternatively, of the functions of the position detection unit 54, the distance between the position of the object 7 obtained by trigonometry and the position of the object 7 estimated based on the estimated movement amount M1 and the estimated movement direction of the vehicle 10 is A function for determining whether or not the distance is shorter than the predetermined distance may be realized by the determination unit 5.

  Further, the second distance threshold Th2 may be equal to the first distance threshold Th1. The second distance threshold Th2 may be a value equal to or smaller than the first distance threshold Th1.

  Further, the sensor system 1 or the external configuration of the sensor system 1 may estimate the course of the vehicle 10 based on the steering angle of the vehicle 10 acquired by the steering angle sensor and output the estimation result to the vehicle control circuit 8. Good. When the object 7 is a detection target and the position of the detection target detected by the position detection unit 54 is outside the estimated course of the vehicle 10, the determination unit 5 determines that the detection target exists. However, the vehicle control circuit 8 may not cause the buzzer to sound a warning sound or operate the brake. That is, in this case, the vehicle control circuit 8 performs processing different from the case where the determination unit 5 determines that the detection target exists and the position of the detection target is within the estimated route of the vehicle 10. Also good.

  The received signal Sig1 is not limited to a signal obtained by converting the reflected wave W2 into an electric signal, and may be a signal indicating the received intensity of the reflected wave W2. For example, the reception signal Sig1 may be a signal indicating the maximum value of the reception intensity of the reflected wave W2.

  In addition, the plurality of sensor units 20 are not limited to being disposed in the front portion of the vehicle 10, and may be disposed in the rear portion, the right portion, and the left portion, for example.

  Further, the number of the sensor units 20 in the sensor 2 is not particularly limited, and may be one or plural.

  Further, in the first embodiment, the determination unit 5 determines whether or not there is a detection target, so that the sensor system 1 is configured to detect the detection target and not detect a non-target object. On the other hand, the determination unit 5 identifies the detection target and the non-target object, and determines whether both the detection target and the non-target object exist, so that the sensor system 1 can detect the detection target and the non-target object. Both of them may be detected. For example, the determination unit 5 reaches the first target number of times when the first number of detections, which is the number of detections of the received signal Sig1 indicating the received wave intensity (the peak value H1) exceeding the first threshold value V1, reaches the first target number. If the second number of detections, which is the number of detections of the received signal Sig1 indicating the received signal intensity exceeding the threshold value V2, is less than the second target number, it may be determined that there is an untargeted object. Alternatively, when the determination unit 5 detects the received signal Sig1 indicating the received wave intensity (crest value H1) exceeding the first threshold value V1 even once, the determination unit 5 determines that there is an out-of-target object. May be.

  In the sensor unit 20, the wave transmitting unit 21 and the wave receiving unit 22 may be provided in a single device, or may be provided separately in a plurality of devices. In the sensor 2, the plurality of sensor units 20 and the control circuit 23 may be provided in a single device, or may be provided separately in a plurality of devices.

(Summary of Embodiment 1)
As described above, the determination system 3 according to the present embodiment includes the acquisition unit 4, the determination unit 5, and the output unit 6. The acquisition unit 4 acquires the received signal Sig1. The received signal Sig1 indicates the received intensity (crest value H1) of the reflected wave W2 that is generated when the detection wave W1 transmitted repeatedly is reflected by the object 7. The determination unit 5 determines the presence / absence of an object corresponding to the detection target among the objects 7 based on the received signal Sig <b> 1 acquired by the acquisition unit 4. The output unit 6 outputs the determination result of the determination unit 5. The determination unit 5 determines that the detection target exists when the first number of detections reaches the first target number and the second number of detections is equal to or greater than the second target number. The first number of detections is the number of detections of the received signal Sig1 indicating the received signal intensity exceeding the first threshold value V1. The second number of detections is the number of detections of the received signal Sig1 indicating the received intensity exceeding the second threshold V2 in the received signal Sig1 indicating the received intensity exceeding the first threshold V1. The second threshold value V2 is larger than the first threshold value V1. The second target number is less than the first target number.

  According to the above configuration, the determination unit 5 uses the two threshold values of the first threshold value V1 and the second threshold value V2, thereby comparing the presence / absence of the detection target as compared with the case where only one threshold value is used. The determination accuracy can be improved.

  Further, in the determination system 3 according to the present embodiment, the determination unit 5 continuously detects the received signal Sig1 indicating the received wave intensity (crest value H1) exceeding the first threshold value V1 by the first target number of times. And when the 2nd detection frequency is more than the 2nd target frequency, it determines with a detection target existing.

  According to the above configuration, the detection wave W1 is reflected by the object 7 that is not the detection target and the reflected wave W2 is generated, and the received wave intensity (the peak value H1) of the reflected wave W2 is temporarily caused by noise or the like. When increasing, the possibility that the determination unit 5 erroneously determines that a detection target exists can be reduced.

  Moreover, the determination system 3 according to the present embodiment further includes a position detection unit 54. The position detection unit 54 detects the position of the object 7. When the position detection unit 54 detects that the object 7 is continuously present in the certain range RA1, the determination unit 5 receives the received signal Sig1 indicating the received intensity (crest value H1) exceeding the first threshold value V1. Is detected, the count number of the first detection count is increased. When the position detection unit 54 does not detect that the object 7 is continuously present in the certain range RA1, the determination unit 5 does not increase the number of first detection times.

  According to said structure, the determination part 5 does not increase the count number of 1st detection frequency, when the position detection part 54 does not detect that the object 7 exists in the fixed range RA1 continuously. Thereby, when the moving object 7 exists, the possibility that the determination unit 5 determines the presence of the object 7 as the detection target can be reduced.

  The sensor system 1 according to this embodiment includes a determination system 3 and a sensor 2. The sensor 2 transmits the detection wave W1, converts the reflected wave W2 into a received signal Sig1, and outputs the received signal to the acquisition unit 4.

  According to said structure, the determination part 5 of the determination system 3 uses two threshold values, the 1st threshold value V1 and the 2nd threshold value V2, and detects compared with the case where only one threshold value is used. The accuracy of determining the presence / absence of a target can be improved.

  Moreover, the determination method according to the present embodiment includes an acquisition step, a determination step, and an output step. In the acquisition step, the received signal Sig1 is acquired. The received signal Sig1 indicates the received intensity (crest value H1) of the reflected wave W2 that is generated when the detection wave W1 transmitted repeatedly is reflected by the object 7. In the determination step, based on the received signal Sig1 acquired in the acquisition step, the presence or absence of an object corresponding to the detection target among the objects 7 is determined. In the output step, the determination result in the determination step is output. In the determination step, when the first number of detections reaches the first target number and the second number of detections is equal to or greater than the second target number, it is determined that the detection target exists. The first number of detections is the number of detections of the received signal Sig1 indicating the received signal intensity exceeding the first threshold value V1. The second number of detections is the number of detections of the received signal Sig1 indicating the received intensity exceeding the second threshold V2 in the received signal Sig1 indicating the received intensity exceeding the first threshold V1. The second threshold value V2 is larger than the first threshold value V1. The second target number is less than the first target number.

  According to the above configuration, in the determination step, by using the two threshold values of the first threshold value V1 and the second threshold value V2, it is determined whether or not the detection target exists compared to the case where only one threshold value is used. Accuracy can be improved.

(Embodiment 2)
Next, Embodiment 2 will be described with reference to FIG.

  In the present embodiment, when the distance L1 between the wave receiver 22 and the object 7 measured by the position detector 54 is shorter than the second distance threshold Th2, the second threshold V2 is the first threshold V1. be equivalent to. When the distance L1 decreases from the first distance threshold Th1 to the second distance threshold Th2, the second threshold V2 decreases until it becomes equal to the first threshold V1.

  On the other hand, when the distance L1 is greater than or equal to the first distance threshold Th1, the second threshold V2 in the present embodiment is the same value as the second threshold V2 in the first embodiment. Further, the first threshold value V1 of the present embodiment is the same value as the first threshold value V1 of the first embodiment.

(Summary of Embodiment 2)
As described above, in the determination system 3 according to the present embodiment, when the measured value of the distance L1 is shorter than the prescribed distance threshold (second distance threshold Th2), the second threshold V2 is the first threshold V1. be equivalent to. The prescribed distance threshold is a value equal to or less than a predetermined distance threshold (first distance threshold Th1).

  According to the above configuration, when the second threshold value V2 is equal to the first threshold value V1, the determination unit 5 compares the received wave intensity (the peak value H1) with the first threshold value V1 and the second threshold value V2. Processing load to be reduced.

  Each embodiment mentioned above may be suitably combined and realized including a modification.

DESCRIPTION OF SYMBOLS 1 Sensor system 2 Sensor 3 Judgment system 4 Acquisition part 5 Judgment part 6 Output part 7 Object 22 Reception part 54 Position detection part H1 Crest value (reception intensity)
RA1 Fixed range Sig1 Received signal V1 First threshold V2 Second threshold W1 Detected wave W2 Reflected wave

Claims (5)

An acquisition unit that acquires a received signal indicating a received intensity of a reflected wave that is generated when a detection wave that is repeatedly transmitted is reflected by an object;
A determination unit that determines the presence or absence of an object corresponding to a detection target among the objects based on the received signal acquired in the acquisition unit;
An output unit that outputs a determination result of the determination unit,
The determination unit reaches the first target number of times, which is the number of detection times of the received signal that indicates the received signal intensity exceeding the first threshold value, and exceeds the first threshold value. In the received signal indicating the wave intensity, a second detection number that is the number of detections of the received signal that indicates the received wave intensity exceeding a second threshold value that is greater than the first threshold value is the first detection value. It is determined that the detection target exists when the number is equal to or more than the second target number less than the target number.
Judgment system. The determination unit continuously detects the reception signal indicating the reception intensity exceeding the first threshold by the first target number of times, and the second detection number is the second target number of times. When it is above, it is determined that the detection target exists.
The determination system according to claim 1. A position detector for detecting the position of the object;
The determination unit detects the reception signal indicating the reception intensity exceeding the first threshold when the position detection unit detects that the object is continuously present in a certain range; Increase the count of the first detection count,
The determination unit does not increase the count number of the first detection times when the position detection unit does not detect that the object is continuously present in the certain range.
The determination system according to claim 1 or 2. The determination system according to any one of claims 1 to 3,
A sensor that transmits the detection wave, converts the reflected wave into the received signal, and outputs the received signal to the acquisition unit;
Sensor system. An acquisition step of acquiring a received signal indicating a received intensity of a reflected wave generated by reflection of a detection wave repeatedly transmitted by an object;
A determination step of determining the presence / absence of an object corresponding to a detection target among the objects based on the received signal acquired in the acquisition step;
An output step for outputting a determination result in the determination step,
In the determination step, the first detection number, which is the number of detections of the received signal that indicates the received signal intensity exceeding the first threshold, reaches the first target number and exceeds the first threshold. In the received signal indicating the wave intensity, a second detection number that is the number of detections of the received signal that indicates the received wave intensity exceeding a second threshold value that is greater than the first threshold value is the first detection value. It is determined that the detection target exists when the number is equal to or more than the second target number less than the target number.
Judgment method.

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