1. A detection system is provided with:

a detection unit (2) having an output function of outputting a detection wave to the periphery of the vehicle and a detection function of detecting an object in the periphery of the vehicle on the basis of a reflected wave formed by reflecting the detection wave by the object; and

a control unit (3) that executes obstacle detection processing in the vicinity of the vehicle when the vehicle is traveling at a speed less than a predetermined speed, and executes rainfall estimation processing and obstacle misdetection suppression processing when the vehicle is traveling at a speed greater than or equal to the predetermined speed,

the control portion determines whether a shift lever of the vehicle is in a parking position after activation of the detection system,

causing the output function in the detection section to operate to transmit the detection wave and detect vibration during transmission and reverberation vibration after the transmission period ends in a case where a shift lever of the vehicle is in a parking position,

when the vibration of the transmission period and the reverberation vibration after the end of the transmission period are correctly detected, the detection unit is determined to be normal,

when the detection part is judged to be normal,

the control unit determines that the object is present in the vicinity of the vehicle if the number of times of detection of the object detected by the detection function of the detection unit exceeds a predetermined number of times in the obstacle detection process;

in the rainfall estimation process, the control unit performs control so that the output function of the detection unit is not executed but the detection function is executed,

in the obstacle erroneous-detection suppressing process, when the number of times of detection of the object by the detection function executed by the control unit is 2 or more, the control unit increases the predetermined number of times,

the control unit determines whether or not the object is present using the increased predetermined number of times in the obstacle detection process executed after the obstacle misdetection suppression process,

the control unit increases the predetermined number of times as the number of times of detection of the object detected by the detection function functioning is increased by the control unit.

2. The detection system of claim 1,

the control unit decreases the predetermined number of times when the predetermined number of times is increased and when the number of times of detection of the object by the detection function functioning by the control unit is not less than 2 times.

3. The detection system of claim 1,

a plurality of the detection portions are arranged in the vehicle,

the control unit increases the predetermined number of times when the plurality of detection units detect the object 2 or more times when the vehicle travels at the predetermined speed or more.

4. The detection system according to any one of claims 1 to 3,

the detection wave is an ultrasonic wave.

5. The detection system of claim 1,

the detection unit (2) is provided with a piezoelectric ceramic vibrator,

the control unit determines that rain has hit the piezoelectric ceramic oscillator when the reflected wave is detected in a state where the detection function is executed without executing the output function.

Background

Systems for detecting obstacles around a vehicle by ultrasonic waves or the like have been developed. For example, in such a system, ultrasonic sensors having a function of transmitting (outputting) ultrasonic waves and a function of receiving (detecting) ultrasonic waves are disposed at a plurality of positions on a bumper of a vehicle. When ultrasonic waves are transmitted from these sensors and then received by the same sensors, the received ultrasonic waves are regarded as reflected waves reflected by objects around the vehicle, and the distance to the object is calculated from the time from transmission to reception, for example, and the distance is reported to the driver when the distance is equal to or less than a predetermined distance.

A technique for suppressing false detection by the ultrasonic sensor is important. For example, patent document 1 listed below discloses an ultrasonic sensor that outputs ultrasonic waves by vibrating a transducer at a frequency different from the resonance frequency of the transducer of the ultrasonic sensor, and determines that the ultrasonic sensor is abnormal when the frequency of a received signal is the resonance frequency.

The present inventors have found that, in a system for detecting an obstacle in the vicinity of a vehicle as described above, when a rain or the like falls and hits a sensor, the sensor may be erroneously detected as receiving a reflected wave. Since rain and the like are frequently occurring phenomena, such false detection may result in a great reduction in reliability of the obstacle detection system. Therefore, development of a system for suppressing such false detection is strongly desired.

Patent document 1: japanese laid-open patent publication No. 2013-104689

Disclosure of Invention

The present disclosure provides a detection system for detecting an object in the vicinity of a vehicle, which reduces the possibility of erroneous detection due to the influence of rainfall or the like.

A detection system according to an aspect of the present disclosure includes: a detection unit having an output function of outputting a detection wave to the periphery of the vehicle and a detection function of detecting an object in the periphery of the vehicle based on a reflected wave formed by the detection wave being reflected by the object; a determination unit that determines that an object is present in the vicinity of the vehicle if the number of times of detection of the object detected by the detection function of the detection unit exceeds a predetermined number of times; a control unit that controls the detection unit so that the output function is not executed but the detection function is executed when the vehicle is traveling at or above a predetermined speed; and an adjustment unit that performs adjustment so as to increase the number of times of the determination unit when the object is detected by the detection function that the control unit executes when the vehicle is traveling at or above a predetermined speed.

According to the detection system of the present disclosure, when the detection function of the detection unit is executed while traveling at or above the predetermined speed and rain or the like is detected as an object, for example, the number of times of detection of the object around the vehicle is increased. This can effectively reduce the possibility of erroneously detecting an object that is originally not desired to be detected, such as rain.

According to the detection system of the present disclosure, it is possible to reduce the possibility of erroneous detection due to the influence of rainfall or the like and detect an object in the vicinity of the vehicle.

Drawings

These and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings, there is shown in the drawings,

figure 1 is a block diagram of one embodiment of a detection system,

fig. 2 is a flowchart showing an example of the processing procedure.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. First, fig. 1 is a schematic diagram of an apparatus configuration of a detection system 1 according to an embodiment of the present disclosure. The detection system 1 is provided in a vehicle, for example, and includes an ultrasonic sensor 2, an ECU3, a display unit 4, an audio output unit 5, a shift lever 6, and a speed sensor 7.

The ultrasonic sensor 2 (hereinafter, referred to as a sensor) is a sensor for detecting an obstacle around the vehicle. The sensor 2 has a structure having not only a microphone function of receiving (receiving, detecting) the ultrasonic wave but also a speaker function of transmitting (transmitting, outputting) the ultrasonic wave. Specifically, the sensor 2 includes a vibrator 20 and a circuit unit 21. The circuit unit 21 includes a transmission circuit 22 and a reception circuit 23, where the transmission circuit 22 is an electronic circuit for transmitting ultrasonic waves and the reception circuit 23 is an electronic circuit for receiving ultrasonic waves. The vibrator 20 may be, for example, a piezoelectric ceramic vibrator.

The detection function is an example of the detection function for detecting an obstacle in the vicinity of the vehicle, that is, detecting an object based on a reflected wave formed by reflecting an ultrasonic wave by the object in the vicinity of the vehicle. In addition, transmitting ultrasonic waves to the periphery of the vehicle to detect waves is an example of an output function.

In the speaker function, the transducer 2 vibrates the transducer 20 by a so-called piezoelectric effect in response to an electric signal transmitted from the wave transmitting circuit 22, thereby transmitting an ultrasonic wave. In the microphone function, ultrasonic waves arriving from the outside vibrate the transducer 20, and an electric signal is generated by the piezoelectric effect and transmitted to the reception circuit 23.

The wave receiving circuit 23 may include, for example, a distance calculating circuit 24. The distance calculation circuit 24 is a circuit for calculating a distance from an object (obstacle) in the vicinity of the vehicle when the received ultrasonic wave is reflected by the object, which is present in the vicinity of the vehicle, as if the ultrasonic wave transmitted from the sensor 2 were received. Specifically, the distance calculation circuit 24 has, for example, a timer function, and may calculate the distance to the obstacle by multiplying the time required from the transmission to the reception of the ultrasonic wave by the speed of the ultrasonic wave and dividing by 2. In addition, the wave receiving circuit 23 may include a filter, a waveform shaping circuit, and the like for removing noise from the received ultrasonic wave.

As shown in fig. 1, the sensor 2 may be provided in plurality on the vehicle. The arrangement positions may be, for example, a plurality of positions at the bumper of the vehicle, for example, two left and right positions of the front bumper, four positions at the rear bumper that are bilaterally symmetrical, and the like. It should be noted that only one sensor 2 may be provided.

The electronic control unit 3(ECU) manages all of the obstacle detection processing in the periphery of the vehicle. The ECU3 has the same configuration as a normal computer, that is, includes a CPU that performs various calculations and information processing, a RAM that is a volatile storage unit as a work area of the CPU, and a memory 30 that is a non-volatile storage unit that stores programs and data necessary for work in the CPU. The memory 30 may store a program 31 used for the processing of the present disclosure.

The detection system 1 further includes a display unit 4, an audio output unit 5, a shift lever 6, and a speed sensor 7 as a configuration related to the present disclosure. The display unit 4 and the sound output unit 5 are configured to report that an obstacle is detected. For example, the display unit 4 may also use an operation display in the vehicle cabin for the purpose of the present disclosure, and report the detection of an obstacle around the vehicle to the vehicle cabin by displaying characters, patterns, and the like. The sound output unit 5 is, for example, a speaker or the like provided in the vehicle interior, and notifies the vehicle interior of the detection of an obstacle in the vicinity of the vehicle by sound (buzzer sound, bell sound, voice, or the like).

As is well known, the shift lever 6 is a part that is operated by a driver to change gears or the like in a transmission of a vehicle, and a current position (shift position) of the shift lever 6 is detected by a position sensor 60. The speed sensor 7 includes a rotation detection unit such as a rotary encoder and detects rotation of a wheel to calculate a speed of the vehicle (or generate information corresponding to the speed of the vehicle). The above devices are connected by an in-vehicle communication line and can exchange information with each other.

The detection system 1 performs a series of processes of the obstacle detection processing of the vehicle periphery, which introduces the new processing of the present disclosure, on the basis of the structure. An example of this process is shown in fig. 2. The processing shown in fig. 2 may be programmed in advance and stored in the memory 30 as the program 31, and the ECU3 may call the program and automatically execute the program.

In the processing of fig. 2, the ECU3 first performs a predetermined initialization processing in S10, and then determines whether or not the shift lever 6 is in the P range (parking range ) based on the output of the position sensor 60 in S20. The process proceeds to S30 when the shift is in the P range (S20: Yes), and proceeds to S60 when the shift is not in the P range (S20: No).

In the case of proceeding to S30, the ECU3 executes the sensor failure detection process at the time of parking through the processes of S30 to S50. Specifically, first in S30, the ECU3 transmits ultrasonic waves from the sensor 2. The sensor 2 has the function of transmitting and receiving ultrasonic waves as described above, but the wave receiving circuit 23 also detects the vibration of the transducer 20 at the time of transmission of ultrasonic waves. The vibration of transducer 20 during ultrasonic transmission includes vibration during a period in which an electric signal for transmission is transmitted from wave transmitting circuit 22 and reverberation vibration of transducer 20 after the end of the period.

In S40, ECU3 determines whether or not all the vibrations until the reverberation is considered to be complete can be accurately detected by the wave receiving circuit 23. If the vibration until reverberation can be accurately detected, it is determined that the sensor 2 is normal, and if the vibration cannot be detected, it is determined that the sensor 2 has failed due to reasons such as freezing of the transducer 20 or disconnection at a position from the transducer 20 to the ECU 3.

If the sensor 2 is determined to be normal (S40: yes), the process returns to S20, and if the sensor is determined to be faulty (S40: no), the process proceeds to S50. When the process proceeds to S50, ECU3 reports to the vehicle cabin that an abnormality of sensor 2 has been detected. The reporting method may be, for example, display by the display unit 4, or voice (voice) output by a voice output unit.

Next, when the process proceeds to S60, ECU3 determines whether the speed of the vehicle is lower or higher than a predetermined speed, based on information from speed sensor 7. If the speed is lower than the predetermined speed (yes in S60), the routine proceeds to S70, and if the speed is higher than the predetermined speed (no in S60), the routine proceeds to S130. The predetermined speed here may be, for example, 10km per hour.

In the case of proceeding to S70, the ECU3 executes obstacle detection processing of the vehicle periphery at the time of low speed through the processing of S70 to S120. On the other hand, when the vehicle enters S130, the ECU3 executes the rainfall estimation process at the time of non-low-speed travel and the process for suppressing erroneous obstacle detection accompanying the rainfall estimation process as the main part of the present disclosure through the processes of S130 to S190.

First, when the process proceeds to S70, the ECU3 transmits the ultrasonic wave from the sensor 2 and receives a signal corresponding to the ultrasonic wave or the like from the sensor 2 when an object such as reflected waves or rain (hereinafter, referred to as ultrasonic waves or the like) in which the transmitted ultrasonic wave is reflected by some object reaches the sensor 2. Here, the ECU3 sets, as a processing target for object detection in the next S80, a signal corresponding to an ultrasonic wave or the like in a period after the time at which reverberation is considered to be completed as described above among the received signals. When the sensor 2 receives the ultrasonic wave or the like, it regards it as a reflected wave from an obstacle around the vehicle and calculates the distance to the obstacle as described above. The transmission, reception, and calculation processes described above may be executed a plurality of times for each of all the sensors 2 provided in the vehicle.

Next, in S80, ECU3 determines whether there is a detection input to sensor 2 (i.e., whether sensor 2 receives a signal corresponding to an ultrasonic wave or the like). The process proceeds to S90 when a detection input is present (S80: Yes), and proceeds to S100 when a detection input is not present (S80: No). When the routine proceeds to S90, ECU3 counts the number of detections (which is set to variable a) by 1. If the process proceeds to S100, the ECU3 resets the number of detections.

In S110, the ECU3 determines whether or not the sensor 2 has detected an obstacle more than a predetermined number of times (determination value) at the same distance. If the number of times is equal to or greater than the predetermined number of times (S110: YES), the process proceeds to S120, and if the number of times is less than the predetermined number of times (S110: NO), the process returns to S20 and repeats. Here, the predetermined number of times may be set in advance as appropriate, or may be set by a user using an input unit provided in the vehicle.

When the process proceeds to S120, the ECU3 reports the presence of an obstacle around the vehicle. Specifically, the report can be given by the display of the display unit 4 and the sound (sound) output by the sound output unit 5. The presence of an obstacle around the vehicle is appropriately reported to the driver or the passenger at a low speed by the above processing. In this case, if the object is not detected a plurality of times in the process of S110, the report is not made, that is, even if an object such as rain collides with the sensor and an object is erroneously detected as being present at a fixed distance from the sensor 2, the report is not made until the object is detected a plurality of times at the same distance.

On the other hand, when the routine proceeds to S130, ECU3 executes the rainfall estimation process during non-low-speed travel, which is the main part of the present disclosure, and further executes the process for suppressing erroneous detection of an obstacle, as described above. Specifically, first in S130, the ECU3 sequentially supplies power to each sensor 2 provided in the vehicle to execute them. However, in this case, only the part related to the reception of the ultrasonic wave (i.e., the wave receiving circuit 23, etc.) is executed without executing the part related to the transmission of the ultrasonic wave (i.e., the wave transmitting circuit 22, etc.). Therefore, the ultrasonic wave is not transmitted from the sensor 2, but is received only.

Then in S140, the ECU3 determines whether there is a detection input in each sensor 2. The process proceeds to S150 in the case where there is a detection input (S140: yes), returns to S20 in the case where there is no detection input (S140: no), and repeats the process. When the process proceeds to S150, the ECU3 increments a detection counter that counts the number of detections by each sensor 2 by 1 (self-increment).

Then, in S160, the ECU3 determines whether or not (the wave receiving circuit 23 of) each sensor 2 has been executed 10 times each, and if not (S160: no), returns to S120. When the reception units of the sensors are each executed 10 times (yes in S160), the process proceeds to S170, and it is determined whether or not the number of times of detection of the ultrasonic waves and the like detected by the plurality of sensors 2 is two or more. If the ultrasonic waves or the like are detected twice or more by the plurality of sensors 2 (yes in S170), the process proceeds to S180, and if not detected (no in S170), the process proceeds to S190.

As described above, no ultrasonic wave is output from the sensor 2 in S130. Therefore, the ultrasonic waves and the like received (detected) in S130 are not reflected waves caused by obstacles around the vehicle. The reception in S130 is considered to be caused by rain hitting the vibrator 20, for example.

Therefore, the process proceeds to S180 when rainfall or the like is detected by the sensor 2 during non-low-speed travel, and the process proceeds to S190 when rainfall or the like is not detected. Therefore, in S180, the ECU3 performs a process of increasing the number of detection determinations (the determination value used in S80). Thus, although the number of times of detection of an object such as rainfall may be included in the number of times of detection at S80 during rainfall, the obstacle is not considered to be detected if a relatively large number of times of detection is not detected during rainfall by the processing at S180, and therefore erroneous detection of an obstacle during rainfall can be suppressed.

On the other hand, when the process proceeds to S190, the ECU3 executes a process of resetting the detection determination count (returning to the default value). Thus, even if rainfall is detected once while the vehicle is traveling and the number of detection determinations is increased in S180, the process proceeds to S190 when the vehicle is subsequently stopped by rain, whereby the number of detection determinations can be returned to the default value suitable for non-rainfall. Therefore, it is possible to appropriately avoid a situation in which it is difficult to detect an obstacle while maintaining a state in which the number of detection determinations is increased even after a rain stop. When the ECU3 ends the processing at S180 or S190, the process returns to S20 and repeats the processing.

The above is the process of fig. 2. By executing the above-described procedure, rainfall or the like is effectively detected by using the non-low-speed travel time, and the number of detection determinations is increased when rainfall or the like is detected, whereby erroneous detection of an obstacle due to the influence of rainfall or the like can be effectively suppressed. In addition, in the case of rain stop, the number of detection determinations is automatically restored to the value at the time of non-rainfall as appropriate. Further, by the determination processing in S60, for example, it is possible to effectively use the detection of rainfall or the like during non-low-speed travel before the obstacle detection is performed at a low speed. In the determination processing in S170, the possibility of erroneous detection of rainfall or the like is reduced compared to a case where rainfall or the like is determined by using one sensor to detect 1 time, for example.

Although rainfall is described above, the rainfall is not limited to rainfall, and may include snow, hail, sleet, and the like, and may be applied to all phenomena that can be detected by the sensor 2. The determination processing in S170 in fig. 2 is 2-value determination of rainfall or non-rainfall, but may be changed to include determination regarding the intensity of rain. For this reason, for example, the processing content in S180 may be changed to processing in which the detection determination count is set to a larger value as the detection count of all the sensors increases. This further increases the number of detection determinations in the case of heavy rain, thereby further reducing the possibility of erroneous detection of an obstacle due to rain.

A detection system according to one aspect of the present disclosure includes: a detection unit having an output function of outputting a detection wave to the periphery of the vehicle and a detection function of detecting an object in the periphery of the vehicle based on a reflected wave formed by reflecting the detection wave by the object; a determination unit that determines that the object is present in the vicinity of the vehicle if the number of times of detection of the object detected by the detection function of the detection unit exceeds a predetermined number of times; a control unit that controls the detection unit so that the output function is not executed but the detection function is executed when the vehicle is traveling at or above a predetermined speed; and an adjustment unit that performs adjustment so as to increase the number of times of the determination unit when the object is detected by the detection function that the control unit executes when the vehicle is traveling at or above a predetermined speed.

According to the detection system of the present disclosure, the detection function of the detection unit is executed while traveling at or above a predetermined speed, and the predetermined number of times used for the object detection determination in the vicinity of the vehicle is increased when, for example, rain or the like is detected as an object. This can effectively reduce the possibility of erroneously detecting an object that is originally not desired to be detected, such as rain.

The above-described embodiments may be modified as appropriate within the scope of the subject matter described in the present disclosure. For example, although the case of the ultrasonic sensor is described in the above example, the present disclosure is not limited to the ultrasonic sensor, and the present disclosure can be applied to all detection units that detect objects around the vehicle and can also detect objects such as rainfall. Note that, although the process of fig. 2 is executed by the single ECU3, a configuration may be employed in which, for example, a plurality of CPUs are provided and the processes of the parts in fig. 2 are executed by the respective CPUs.

The flowchart or the processing of the flowchart described in the present application is configured by a plurality of steps (or referred to as sections), and each step is expressed as S10, for example. Each step can be divided into a plurality of substeps, or a plurality of steps can be combined into one step.

Although the embodiments, configurations, and shapes of the detection system according to the present disclosure have been described above, the embodiments, configurations, and shapes of the detection system according to the present disclosure are not limited to the above-described embodiments, configurations, and shapes. For example, embodiments, structures, and shapes obtained by appropriately combining technical elements disclosed in different embodiments, structures, and shapes are also included in the scope of the embodiments, structures, and shapes according to the present disclosure.