ULTRASOUND SENSOR AND OBJECT DETECTION SYSTEM

Abstract

Ultrasonic sensor (10) for transmitting a test wave signal from test waves at each transmission time, comprising: a transmission section (14) which includes a piezoelectric element (141) and is configured such that the piezoelectric element (141) oscillates based on electrical energy supplied to it in order to transmit the test wave signal; a transmission circuit (13) that supplies the electrical energy to the piezoelectric element (141); and a transmission control section (12) that is configured to: Driving the transmission circuit (13) for each transmission time to cause the transmission section (14) to send the test wave signal; Switching from a first transmission characteristic of the test wave signal to a second transmission characteristic when a predetermined interval has elapsed since the start of the transmission of the test wave signal, wherein each of the first and second transmission characteristics of the test wave signal includes at least a phase, a frequency, a period and an amplitude of the test wave signal; Setting a switch-off period to interrupt the supply of electrical energy from the transmission circuit (13) to the piezoelectric element (141) when switching from the first transmission characteristic of the test wave signal to the second transmission characteristic of the same; and Switching for each transmission time whether the shutdown period should be provided, whereby the shutdown period is provided in at least one of the transmission times and is not provided in at least one other of the transmission times.

Description

[Technical field]

[0001] The invention relates to an ultrasonic sensor and an object recognition system. [State of the art]

[0002] In the prior art, ultrasonic sensors were implemented which transmit ultrasonic waves as test waves, receive reflected waves reflected by an object, and detect the distance and relative velocity of the object.

[0003] Such an ultrasonic sensor is described in JP 4 283 170 B2. In the ultrasonic sensor described in JP 4 283 170 B2, after transmitting test waves with a specific phase, the transmission of test waves with a different phase is continued. When received waves containing reflected waves are received, a comparison of the phase of the received waves with the phase of the test waves determines whether the received waves are reflected waves.

[0004] When the phase, etc., is switched, as in the ultrasonic sensor described in JP 4 283 170 B2, a waveform disturbance occurs during the transition from oscillation in phase before the switch to oscillation in phase after the switch. This means that there are time periods or intervals in which the accuracy of the phase control, etc., is reduced, and in which the accuracy of determining whether the received waves are reflected waves is also reduced.

[0005] US Patent 4,905,207 A discloses a device for measuring distances from a source to an object, in particular using at least two signals of different frequencies to perform distance measurements.

[0006] DE 10 2012 211 630 A1 teaches a driver assistance system for a vehicle with at least one ultrasonic sensor for determining the distance of the vehicle to an obstacle, wherein the sensor is supplied with electrical energy by an on-board network of the vehicle, as well as a corresponding method for operating such a driver assistance system.

[0007] The object of the present invention is to provide an ultrasonic sensor which, while enabling the switching of the phase etc. during the transmission of the test waves, enables greater stability of the test waves after switching as well as the detection of objects at short distances.

[0008] The problem is solved by the subject matter of the independent claims. Advantageous further developments are specified in the dependent claims.

[0009] According to the invention, since a switch-off period is provided at the time when the transmission characteristics are switched, the oscillation of the transmission characteristics prior to the switching of the piezoelectric element is attenuated during this switch-off period. Thus, the transmission of the test waves can begin in a more stable state after the switching of the transmission characteristics has been performed. Furthermore, if the test waves are transmitted using energy supplied by a capacitor, the switch-off time can be used to charge the capacitor. This ensures that sufficient energy is supplied to the piezoelectric element to transmit the test waves after the switching of the transmission characteristics, and that the test waves can be transmitted in a more stable state after the switching of the transmission characteristics. [Brief description of the drawings]

[0010] The foregoing objective and other objectives, features, and advantages of the invention will become more apparent from the following detailed description, which refers to the accompanying drawings. These show: Fig. 1. A diagram showing the configuration of an object detection system. Fig. 2 a diagram showing the configuration of a transmitter-receiver circuit. Fig. 3 a diagram showing an amplitude and a phase when no shutdown period is provided. Fig. 4 a diagram showing an amplitude and a phase when a shutdown period is provided. Fig. 5 a diagram showing a transmission phase of an object recognition system according to a second embodiment. Fig. 6 a diagram showing a transmission phase of an object recognition system according to a third embodiment. Fig. 7 a diagram showing a transmission phase of an object recognition system according to a fourth embodiment. Fig. Figure 8 shows a diagram illustrating a transmission phase of an object recognition system according to a fifth embodiment. Fig. 9 a diagram showing a transmission phase of an object recognition system according to a sixth embodiment. Fig. 10 a diagram showing a transmission phase of an object recognition system according to a seventh embodiment. Fig. 11 a diagram showing a transmission phase of an object recognition system according to an eighth embodiment. Fig. 12 a diagram showing a modified example of an object recognition system according to the eighth embodiment. Fig. 13 a diagram showing a transmission frequency of an object detection system according to a ninth embodiment. Fig. 14 a diagram showing a transmission frequency of an object detection system according to a tenth embodiment. Fig. 15 a diagram showing a transmission frequency of an object recognition system according to an eleventh embodiment. Fig. 16 a diagram showing a transmission frequency of an object detection system according to a twelfth embodiment. (Examples of implementation)<Erstes Ausführungsbeispiel>

[0011] An object detection system according to the present embodiment is mounted on a vehicle, which is a moving body, and includes an ultrasonic sensor. At each predetermined transmission time, the ultrasonic sensor sends a test wave signal containing ultrasonic waves and receives a reception wave signal at each predetermined reception time. This reception wave signal consists of waves reflected from an object in the vicinity of the vehicle. The ultrasonic sensor then determines the distance between the vehicle and the object by measuring the time elapsed between the transmission of the test wave signal and the reception of the reception wave signal. If the distance between the vehicle and the object is less than a predetermined distance, the driver is notified that the object is approaching, or a braking device provided on the vehicle is activated.

[0012] Fig. Figure 1 is a configuration diagram of an object detection system according to the exemplary embodiment. The object detection system includes a plurality of ultrasonic sensors 10 and an electronic control unit or ECU 21, which is connected to communicate with the ultrasonic sensors 10.

[0013] The ultrasonic sensors 10 are arranged at a distance from each other, and when test waves are emitted by one of the ultrasonic sensors 10 and reflected by an object in the vicinity, the reflected waves can be received by any of the ultrasonic sensors 10. That is, an ultrasonic sensor 10 can receive both direct waves, which are the reflected waves of the test waves transmitted by that sensor, and indirect waves, which are the reflected waves of the test waves transmitted by another sensor.

[0014] Each ultrasonic sensor 10 includes a communication section 11, which communicates with the ECU 21; a transmission control section 12, which receives a test wave transmission control start signal from the communication section 11 and performs the transmission control of the test waves; and a transmission circuit 13, which is controlled by the transmission control section 12. When the transmission circuit 13 is controlled by a control signal from the transmission control section 12, a control current with a predetermined frequency is supplied to the transceiver or transmitter-receiver section 14.

[0015] The transmission control section 12 receives a modulation signal from the modulation section 17 and transmits a driver or control signal based on the modulation signal to the transmission circuit 13. In particular, the modulation section 17 detects pulse trains, each consisting of a plurality of pulses from the signal generation section 16, and changes the phase of each pulse train in accordance with a code sequence consisting of a combination of a plurality of codes. A pulse train whose phase has been changed is fed to the transmission control section 12 as a modulation signal.

[0016] The transmitter-receiver section 14 has a known configuration which includes a piezoelectric element. The drive current with a predetermined frequency is supplied to the piezoelectric element by the transmission circuit 13, causing the piezoelectric element to vibrate and transmit ultrasonic waves as the test waves.

[0017] If the test waves are reflected by an object in the vicinity after being emitted, the reflected waves, which are reflected ultrasonic waves, reach the transmitter-receiver section 14. Furthermore, if a device that generates ultrasonic waves, such as another ultrasonic sensor, is nearby, the ultrasonic waves emitted by this device will also reach the transmitter-receiver section 14. Such ultrasonic waves emitted by another device are called interference waves.

[0018] The piezoelectric element contained in the transmitter-receiver section 14 is set into vibration by the received waves and generates an electrical signal with a frequency equal to the frequency of the received wave signal and a voltage proportional to the amplitude of the received wave signal. The electrical signal generated by the piezoelectric element is fed to the receiving circuit 15.

[0019] The transmission circuit 13, the transmitter-receiver section 14 and the receiving circuit 15 configured as described above are referred to below. Fig. 2 described in more detail.

[0020] The transmission circuit 13 includes a first coil 131 with a center tap and a second coil 132, which is magnetically coupled to the first coil 131. One end of each of switches 133 and 134 is connected to the respective ends of the first coil 131, and the other ends of switches 133 and 134 are connected to ground. A current source 136 is connected to the center tap of the first coil 131 via a resistor 135. One end of a capacitor 137 is connected between the center tap of the first coil 131 and the resistor 135, and the other end of the capacitor 137 is connected to ground.

[0021] The second coil 132 of the transmission circuit 13 is connected to the transmitter-receiver section 14 via the receiver circuit 15. In particular, one end of the second coil 132 is connected via a resistor 151 to one end of the piezoelectric element 141 of the transmitter-receiver section 14, and the other end of the second coil 132 is connected to the other end of the piezoelectric element 141.

[0022] The second coil 132 is connected in series with resistor 151 to form a series circuit. Between the piezoelectric element 141 and the series circuit, a capacitor 152 and a resistor 153 are connected in parallel, in that order, starting from the piezoelectric element 141. A noise filter circuit is configured by the capacitor 152 and the resistor 153, which filters out electrical signals from the piezoelectric element 141 that are within a predetermined frequency band and excludes electrical signals that are outside the predetermined frequency band. The electrical signal passed through the noise filter circuit is output by the voltage output section 154.

[0023] To Fig. Returning to the receiving circuit 15, the electrical signal output is fed to the phase calculation section 18 and the distance calculation section 20. The phase calculation section 18 receives signals from the demodulator 19, which are used to demodulate the received wave signal, and demodulates the received wave signal. Specifically, a sine wave signal and a cosine wave signal, used for quadrature demodulation, are received, and the received wave signal is multiplied by the sine wave signal to obtain an in-phase component and by the cosine wave signal to obtain a quadrature phase component. The phase of the received wave signal is then determined based on the obtained in-phase component and the quadrature phase component.

[0024] The distance calculation section 20 determines the time elapsed from the transmission time of the test wave signal to the reception time of the received wave signal and multiplies half of this time by the speed of sound, with the result being considered the distance from the object. Information regarding the transmission time of the test waves is obtained from the transmission control section 12. The reception time of the received wave signal is defined as the time at which the voltage value received by the receiving circuit 15 exceeds a predetermined threshold.

[0025] The phase of the received wave signal calculated by phase calculation section 18 and the distance calculated by distance calculation section 20 are transmitted by communication section 11 to ECU 21. Communication section 22 of ECU 21 sends the received phase of the received wave signal and the distance to determination section 23. Determination section 23 compares the received phase of the received wave signal with the phase of the test wave signal. If the difference between the received phase of the received wave signal and the phase of the test wave signal does not exceed a predetermined value, it is determined that the received waves are reflected waves of the test waves. ECU 21 uses the received distance to inform the vehicle driver that they are approaching an object in the vicinity or to initiate braking to avoid a collision with the object.

[0026] When the ultrasonic sensor 10, configured as described above, is used to determine the distance of an object in the environment, interference or noise waves that are not reflected waves of the test waves can be received as received waves. Therefore, the transmission control section 12 of the ultrasonic sensor 10, according to the present embodiment, performs a control to change the phase of the test wave signal after a predetermined time has elapsed since the start of the test wave signal transmission. More precisely, if the phase of the test wave signal is 180° at the start of the test wave signal transmission, the test wave signal is transmitted with the phase inverted to 0° after a predetermined time has elapsed. The phase of the test wave signal can be described as a transmit or receive phase.The transmission characteristic can be referred to as the transmission characteristic, and the phase of the received wave signal can be referred to as a receiving characteristic. The phase calculation section 18, which calculates the phase of the received wave signal, can be referred to as a characteristic detection section.

[0027] When implementing the phase inversion control in this manner, sufficient energy is required to transmit the test wave signal with the inverted phase. However, as described above, the transmission of the test wave signal uses electrical energy accumulated in capacitor 152. Therefore, the electrical energy accumulated in capacitor 152 decreases as the test wave signal is transmitted. The amplitude and phase of the test wave signal in this case are determined with reference to Fig. 3 described. The in Fig. The amplitude shown in section 3 represents an envelope of the waveform of the received wave signal.

[0028] Fig. Figure 3 shows an example in which the control of setting the phase of the test wave signal to 180° is started at time t11 and the control is changed to the control of setting the phase of the test wave signal to 0° at time t12, and then the transmission of the test wave signal is stopped at time t13.

[0029] If, at time t11, a drive voltage is applied to the piezoelectric element 141, the amplitude increases accordingly, and the test wave signal is then transmitted with a phase of 180°. The control of the transmission circuit 13 causes the transmission circuit 13 to transmit the test wave signal with a phase of 0° at time t12. In this case, the control of the transmission circuit 13 to transmit the test wave signal with a phase of 180° is terminated when half a period (1 / 2T) has elapsed since the excitation of the piezoelectric element 141 ceased. The excitation of the piezoelectric element 141 is initiated when half a period (1 / 2T) has elapsed since the phase of the test wave signal was controlled to be set to 0°.This results in the interval between the end of the excitation of the piezoelectric element 141 for transmitting the test wave signal with a phase of 180° and the beginning of the excitation of the piezoelectric element 141 for transmitting the test wave signal with a phase of 0° becoming one period (T). Because the piezoelectric element 141 oscillates with a phase of 180°, it is necessary at this point to stop the oscillations of the piezoelectric element 141 and then cause the piezoelectric element 141 to oscillate with a phase of 0°. Since, as described above, the electrical energy stored in the capacitor 152 has decreased, it takes some time for the oscillations of the piezoelectric element 141 with a phase of 0° to stabilize and for a peak value of the amplitude envelope to be reduced.

[0030] From this perspective, the ultrasonic sensor 10, according to the present embodiment, is configured such that the transmission control section 12 defines a switch-off period at a point in time when a predetermined time has elapsed since the start of the transmission of the test wave signal, during which no energy is supplied to the piezoelectric element 141. The length of the switch-off period according to the present embodiment is set to four times the length of period T.

[0031] The amplitude and phase of the test wave signal are determined in this case with reference to Fig. 4 described. The amplitude of the in Fig. The amplitude envelope of the test wave signal shown in Figure 4 represents the test wave signal. Fig. Figure 4 shows an example in which the control of the setting of the phase of the test wave signal to 180° is started at time t21, the switch-off period is set from time t22 to time t23, and after the switch-off period the control of the setting of the phase of the test wave signal to 0° is started at time t23, and then the transmission of the test wave signal is ended at time t24.

[0032] If the application of the drive voltage to the piezoelectric element 141 begins at time t21, the amplitude increases accordingly, and the test wave signal is then transmitted with a phase of 180°. Stopping the excitation of the piezoelectric element 141 for the switch-off period starting at time t22 allows the amplitude envelope to be reduced and the capacitor 152 to be charged. Since the length of the switch-off period is four periods (4T) from the time the control of the transmission circuit 13 for the phase of the test wave signal that becomes 180° is terminated, the transmission of the test wave signal with a phase of 0° begins 4.5 periods (4.5T) later than the end of the control of the transmission circuit 13 for the phase of the test wave signal that becomes 180°.

[0033] Since the shutdown period is provided in this way, capacitor 152 is charged during the shutdown period. Furthermore, the amplitude of the test wave signal is attenuated during the shutdown period. This results, as in Fig. As shown in Figure 4, the phase of the test wave signal stabilizes at 0° or approximately there during the interval from time t23 to time t24. Furthermore, the peak amplitude value following the shutdown period is essentially the same as the peak amplitude value before the shutdown period.

[0034] In this embodiment, the length of the switch-off period is four times the period of the test waves, but the length of the switch-off period is not limited to this. That is, the length of the switch-off period can be longer than a first length, which is the product of a first predetermined value and the period of the test wave signal, and shorter than a second length, which is the product of a second predetermined value and the period of the test wave signal. In this case, the first predetermined value can be set based on the time required for a sufficient amount of charge to accumulate in the capacitor 152 to drive the piezoelectric element 141, while the second predetermined value can be set based on the time required to charge the capacitor 152 to saturation.In other words, the length of the shutdown period is determined by the capacitance of capacitor 152, the current supplied to capacitor 152 by the power source 136, etc.

[0035] If the length of the shutdown period is made longer than a first predetermined value of the test wave period, the amplitude at the beginning of the test wave transmission after switching the transmission characteristics will be sufficiently small, and an adequate charging time for capacitor 152 can be ensured. Furthermore, if the length of the shutdown period is made shorter than a second predetermined value of the test wave period, the length of a single transmission can be limited, while ensuring a sufficient duration for receiving the received waves.

[0036] Furthermore, it would be equally possible for the transmission control section 12 to switch between providing and not providing a shutdown period during each transmission opportunity. If the transmission of test waves and the reception of reflected waves are performed by a transmitter-receiver section 14, the reflected waves cannot be received during the transmission of the test waves. This means that as the length of a transmission opportunity increases, the start of the period in which the received waves can be received is delayed more significantly, making it impossible to detect an object at close range. In particular, since a shutdown period is provided at the time of the switching of the transmission characteristics, the length of a transmission opportunity increases, thus making the detection of objects at close range more difficult.In this context, selectively switching between providing and not providing a shutdown period for each test wave transmission option makes it possible to detect a closely located object in the next transmission option, even if it is difficult to detect such an object in a particular transmission option by providing a shutdown period, since no shutdown period is provided in the next transmission option. Therefore, it is possible to accurately detect objects at close range while the transmission characteristics are being switched.

[0037] With the above configuration, an ultrasonic sensor according to this embodiment has the following effects.

[0038] Since a switch-off time is provided at the time of the phase switch, this switch-off time can be used to charge the capacitor 152. This allows sufficient energy to be supplied to the piezoelectric element 141 to transmit the test waves after the phase switch has taken place, and enables the transmission of the test waves to be carried out in a more stable state after the switching of the transmission characteristics.

[0039] Since a shutdown period is provided at the time of the phase switch, the phase oscillation of the piezoelectric element 141 is reduced during the shutdown period. This allows the transmission of the test waves to begin in a more stable state after the switching of the transmission characteristics. <Zweites Ausführungsbeispiel>

[0040] In the present embodiment, the ultrasonic sensors contained in the object detection system have a specific arrangement. The arrangement of the ultrasonic sensors contained in the object detection system is described below with reference to Fig. 5 described.

[0041] As in Fig. As shown in Figure 5, the first to fourth front sensors 31 to 34 are provided at the front end of the vehicle, arranged in sequence starting from the left side and spaced apart (adjacent to each other). At the rear end of the vehicle, the first to fourth rear sensors 41 to 44 are provided, arranged in sequence starting from the left side and spaced apart (adjacent to each other). The first and second left-side sensors 51 and 52 are provided on the left side of the vehicle, arranged in sequence from front to rear and spaced apart (adjacent to each other). Additionally, two right-side sensors 61 and 62 are provided on the right side of the vehicle, arranged in sequence from front to rear and spaced apart (adjacent to each other).The first front sensor 31 and the first left-side sensor 51 are arranged adjacent to each other. The fourth front sensor 34 and the first right-side sensor 61 are arranged adjacent to each other. The first rear sensor 41 and the second left-side sensor 52 are arranged adjacent to each other. The fourth rear sensor 44 and the second right-side sensor 62 are arranged adjacent to each other.

[0042] The first to fourth front sensors 31 to 34, the first left-side sensor 51, and the first right-side sensor 61 are mounted on the front bumper of the vehicle. The first to fourth rear sensors 41 to 44, the second left-side sensor 52, and the second right-side sensor 62 are mounted on the rear bumper of the vehicle. The specific configurations of the first to fourth front sensors 31 to 34, the first to fourth rear sensors 41 to 44, the first and second left-side sensors 51 and 52, and the first and second right-side sensors 61 and 62 are as follows. These configurations are the same as those of the ultrasonic sensor 10 of the first embodiment. That is, sensors 31 to 34, 41 to 44, 51, 52, 61, and 62 have a common configuration.

[0043] In Fig. Sensor 5, indicated by a triangle, transmits test waves with a modified phase, while sensor 5, indicated by a circle, transmits test waves with an unchanged phase. This means that the first to fourth front sensors 31 to 34 and the first to fourth rear sensors 41 to 44 are configured to transmit test waves with a modified phase, while the first and second left-side sensors 51 and 52, and the first and second right-side sensors 61 and 62, are configured to transmit test waves with an unchanged phase.

[0044] In an object detection system with the above configuration, sensors that are spaced close to each other can receive, in addition to the reflected waves of the test waves transmitted by the sensor itself, the reflected waves of test waves transmitted by another sensor.

[0045] The following description details the left front sensor group of the vehicle, i.e., the first front sensor 31, the second front sensor 32, and the first left-side sensor 51. The right front sensor group, the left rear sensor group, and the right rear sensor group of the vehicle have the same functions as the left front sensor group and are not described in detail.

[0046] In the left front sensor group of the vehicle, the first front sensor 31 can receive, in addition to receiving the reflected waves of the test waves transmitted by the first front sensor 31 itself, the reflected waves based on the test waves of the second front sensor 32, as well as the reflected waves based on the test waves of the left-side sensor 51. Furthermore, the first left-side sensor 51 can receive, in addition to the reflected waves of the test waves transmitted by the first left-side sensor 51 itself, the reflected waves of the test waves of the first front sensor 31.

[0047] As described above, the first front sensor 31 and the second front sensor 32 are configured to transmit a test wave with a changed phase, and the first left-side sensor 51 is configured to transmit a test wave with an unchanged phase. That is, the first front sensor 31 and the first left-side sensor 51, which are located adjacent to each other on the vehicle, transmit test waves with different phases (transmission characteristics).

[0048] Since the presence or absence of a phase change of the test waves is determined in this way, it is then possible, when the second front sensor 32 and the first left-side sensor 51 transmit test waves, to determine, for reflected waves incident on the first front sensor 31, which sensor emitted the test waves on which these reflected waves are based.

[0049] Furthermore, if the first front sensor 31 and the first left-side sensor 51 transmit test waves, it is possible to determine, for reflected waves incident on the first front sensor 31, which sensor emitted the test waves on which these reflected waves are based, and it is also possible to determine, for reflected waves incident on the first left-side sensor 51, which sensor emitted the test waves on which these reflected waves are based. <Drittes Ausführungsbeispiel>

[0050] In this embodiment, the overall configuration of the object detection system is the same as that of the second embodiment, while some of the transmission phases defined by the respective sensors differ from those of the second embodiment. An object detection system according to this embodiment is described below with reference to Fig. 6 described.

[0051] In Fig. As in the second embodiment, a sensor that emits test waves with a changed phase is indicated by a triangle, and a sensor that emits test waves with an unchanged phase is indicated by a circle. That is to say, the first to fourth front sensors 31 to 34, the second left-hand sensor 52, and the second right-hand sensor 62 are configured to emit test waves with a changed phase, while the rear sensors 41 to 44, the first left-hand sensor 51, and the first right-hand sensor 61 are configured to emit test waves with a unchanged phase.

[0052] When the object detection system is configured as described above, the first left-hand sensor 51 can receive the reflected waves of test waves transmitted by the adjacent second left-hand sensor 52, and the second left-hand sensor 52 can receive the reflected waves of test waves transmitted by the adjacent first left-hand sensor 51. The first right-hand sensor 61 can receive the reflected waves of test waves transmitted by the adjacent second right-hand sensor 62, and the second right-hand sensor 62 can receive the reflected waves of test waves transmitted by the adjacent first right-hand sensor 61.Since the phase of the test waves transmitted by the first left-hand sensor 51 is not changed, and the phase of the test waves transmitted by the second left-hand sensor 52 is changed, it is possible to determine that received waves are reflected waves of test waves transmitted by which of the first left-hand sensor 51 and the second left-hand sensor 52. Similarly, since the phase of the test waves transmitted by the first right-hand sensor 61 is not changed, and the phase of the test waves transmitted by the second right-hand sensor 62 is changed, it is possible to determine that received waves are reflected waves of test waves transmitted by which of the first right-hand sensor 61 and the second right-hand sensor 62.

[0053] The left front sensor group, the right front sensor group, the left rear sensor group and the right rear sensor group of the vehicle have the same functions as those of the second embodiment, so a specific description is omitted.

[0054] An object recognition system according to the present embodiment exhibits the same effects as those of the first embodiment due to the above configuration.

[0055] Furthermore, three or more sensors can be provided on the left side, with the transmission phases (transmission characteristics) of the respective test waves of adjacent sensors differing from one another. This means that at least two sensors (object detection devices) are provided adjacent to each other on the left side of the vehicle, with the respective transmission characteristics of adjacent sensors differing from one another. This also applies to the sensors on the right side. <Viertes Ausführungsbeispiel>

[0056] In this embodiment, the overall configuration of the object detection system is the same as that of the second embodiment, while parts of the transmission phases of the respective sensors differ from those of the second embodiment. An object detection system according to the present embodiment is described below with reference to Fig. 7 described.

[0057] In Fig. As in the second embodiment, a sensor that transmits test waves whose phase is changed is indicated by a triangle, and a sensor that transmits test waves whose phase does not change is indicated by a circle. In other words, the first and second front sensors 31, 32, the third and fourth rear sensors 43, 44, the second left-side sensor 52, and the first right-side sensor 61 are configured to emit test waves whose phase is changed. The third and fourth front sensors 33 and 34, the first and second rear sensors 41 and 42, the first left-side sensor 51, and the second right-side sensor 62 are configured to emit test waves whose phase is unchanged.

[0058] The following description refers to the sensor group at the front of the vehicle, i.e., the first to fourth front sensors 31 to 34. The sensor group at the rear of the vehicle, i.e., the first to fourth rear sensors 41 to 44, has the same functions as the sensor group at the front of the vehicle, so a detailed description of it is omitted.

[0059] In the object detection system configured as described above, the second front sensor 32 can receive, in addition to the reflected waves of the test waves emitted by the second front sensor 32 itself, reflected waves based on the test waves of the adjacent first front sensor 31, and can furthermore receive reflected waves based on the test waves of the adjacent third front sensor 33. The third front sensor 33 can receive, in addition to reflected waves based on the test waves emitted by the third front sensor 33 itself, reflected waves of the test waves of the adjacent second front sensor 32, and can furthermore receive reflected waves based on the test waves of the adjacent fourth front sensor 34.

[0060] As described above, the first and second front sensors 31 and 32 are configured to emit test waves whose phase is changed, and the third and fourth front sensors 33 and 34 are configured to emit test waves whose phase is not changed.

[0061] Since the presence or absence of a phase shift in the test waves is determined in this way when the first front sensor 31 and the third front sensor 33 transmit test waves, it is possible to determine, for reflected waves that reach the second front sensor 32, which of the sensors emitted the test waves on which these received waves are based. Similarly, when the second front sensor 32 and the fourth front sensor 34 transmit test waves, it is possible to determine, for reflected waves that reach the third front sensor 33, which of the sensors emitted the test waves on which these received waves are based.

[0062] Furthermore, if the second front sensor 32 and the third front sensor 33 transmit test waves, it is possible to determine that incident reflected waves are based on test waves transmitted by which of the second front sensor 32 and the third front sensor 3.

[0063] The left front sensor group, the right front sensor group, the left rear sensor group and the right rear sensor group of the vehicle have the same functions as those in the second embodiment, so a detailed description of them is omitted.

[0064] An object recognition system according to the present embodiment has the same effects via the above configuration as those of the first embodiment.

[0065] Furthermore, for all of the first to fourth front sensors 31 to 34, the transmission phases (transmission characteristics) of the respective test waves of adjacent sensors can differ from one another. This means that at least two sensors (object detection devices) that are adjacent to each other are provided at the front end of the vehicle, and the transmission characteristics of adjacent sensors in these at least two sensors can differ from one another. This also applies to the sensors provided at the rear of the vehicle. <Fünftes Ausführungsbeispiel>

[0066] In this embodiment, the overall configuration of the object recognition system is the same as that of the second embodiment, while part of the processing differs from that of the second embodiment. An object recognition system according to the present embodiment is described below with reference to Fig. 8 described.

[0067] In the present embodiment, a first setting or adjustment mode (shown in Fig. 8(a)), in which the transmission phase is defined in the same way as in the second embodiment, and a second setting or adjustment mode (shown in Fig. 8(b)), in which the transmission phase is defined differently than in the second embodiment, by switching between them.

[0068] In the second setting mode, as in Fig. As shown in Figure 8B, in the case of a sensor that transmits test waves with a changed phase in the first setting mode, the sensor transmits the test waves with the unchanged phase, while in the case of a sensor that transmits test waves with an unchanged phase in the first setting mode, the sensor transmits the test waves with the changed phase. That is, the first to fourth front sensors 31 to 34 and the first to fourth rear sensors 41 to 44 are set to transmit the test waves with the unchanged phase, while the first and second left-side sensors 51 and 52 and the first and second right-side sensors 61 and 62 are set to transmit the test waves with a changed phase.

[0069] The switch between the first and second setting modes occurs at each of the respective predefined periods or time intervals. The predefined period can be a period in which a transmitter-receiver control is executed once for each sensor, or it can be defined as a period in which the transmitter-receiver control is executed multiple times for each sensor.

[0070] An object recognition system according to the present embodiment exhibits the following effects via the above configuration.

[0071] If another ultrasonic sensor is located near the object detection system and transmits test waves with a presence / absence of a phase change common to that of the object detection system, then test waves transmitted by this other ultrasonic sensor can be received and incorrectly identified as reflected waves based on test waves transmitted by the object detection system itself. In this regard, in the present embodiment, since the presence / absence of phase changes is switched at each of the prescribed periods, the presence / absence of a phase change can be differentiated from that of another ultrasonic sensor, thus suppressing interference. <Sechstes Ausführungsbeispiel>

[0072] In this embodiment, the overall configuration of the object detection system is the same as that of the second embodiment, while part of the transmission phase of each sensor differs from that of the second embodiment. An object detection system according to the present embodiment is described below with reference to Fig. 9 described.

[0073] In the present embodiment, a phase change is performed for each of the sensors, and the phases in which a change can be performed are a first phase, a second phase, and a third phase.

[0074] In Fig. Sensor 9, which transmits test waves in the first phase, is indicated by a triangle; sensor 9, which transmits test waves in the second phase, is indicated by a circle; and sensor 1, which transmits test waves in the third phase, is indicated by a square. That is to say, the first to fourth front sensors 31 to 34 and the first to fourth rear sensors 41 to 44 are designated to transmit test waves in the first phase; the first and second left-side sensors 51 and 52 are designated to transmit test waves in the third phase; and the first and second right-side sensors 61 and 62 are designated to transmit test waves in the second phase.

[0075] By setting the transmission frequency in this way, an object detection system according to this embodiment has the following effects in addition to the effects shown by an object detection system according to the second embodiment.

[0076] When a vehicle with an object detection system according to the present embodiment and a vehicle with the same object detection system are moving parallel to each other, the left side of one vehicle and the right side of the other vehicle are close together. At this point, the smaller the distance between the vehicles, the easier it is to receive test waves transmitted by the sensors of the other vehicle. Since, according to this embodiment, the phases of the first and second left-side sensors 51 and 52 differ from the phases of the first and second right-side sensors 61 and 62 when the vehicles are positioned side by side and test waves transmitted by the object detection system of the other vehicle are received, the determining clause 103 can stipulate that the received waves are by test waves, etc.This can prevent interference caused by another object detection system and avoid using these received waves for its own distance measurement. Accordingly, when vehicles with object detection systems with a configuration equivalent to those of the present embodiment are positioned side by side, crosstalk can be suppressed.

[0077] Furthermore, the first to fourth front sensors 31 to 34 may be omitted, the first to fourth rear sensors 41 to 44 may be omitted, or the first to fourth front sensors 31 to 34 and the first to fourth rear sensors 41 to 44 may be omitted. <Siebtes Ausführungsbeispiel>

[0078] In this embodiment, the overall configuration of the object detection system is the same as that of the second embodiment, while part of the transmission phase of each sensor differs from that of the second embodiment. An object detection system according to the present embodiment is described below with reference to Fig. 10 described.

[0079] In the present embodiment, as in the sixth embodiment, a first phase, a second phase and a third phase are used.

[0080] In Fig. Sensor 10, which transmits test waves in the first phase, is indicated by a triangle; sensor 2, which transmits test waves in the second phase, is indicated by a circle; and sensor 3, which transmits test waves in the third phase, is indicated by a square. That is, the first to fourth front sensors 31 to 34 are designated to transmit test waves in the second phase, and the first to fourth rear sensors 41 to 44 are designated to transmit test waves in the third phase. The first and second left-side sensors 51 and 52, and the first and second right-side sensors 61 and 62, are designated to transmit the test waves in the first phase.

[0081] By setting the transmission frequency in this way, an object detection system according to this embodiment provides the following effects in addition to the effects shown by an object detection system according to the second embodiment.

[0082] When vehicles, each equipped with an object detection system with the same configuration as that of the exemplary embodiment, are arranged in a line, for example, when traveling along a congested road, the front end of one vehicle and the rear end of another will approach each other. The smaller the distance between the vehicles, the more easily test waves transmitted by the object detection system of one vehicle will be received by another vehicle at that time.In the present embodiment, the phases of the front sensors 31 to 34 and the phases of the rear sensors 41 to 44 differ from each other. Therefore, if the vehicles are arranged in a row and one vehicle has received the test waves of an object detection system provided in another vehicle, the determining section 103 can determine that the received waves are caused by the test waves, etc., of another object detection system and can avoid using them for its own distance measurement. Thus, if vehicles with object detection systems with a configuration equivalent to that of the present embodiment are arranged in a row, crosstalk can be suppressed. <Achtes Ausführungsbeispiel>

[0083] In this embodiment, the overall configuration of the object detection system is the same as that of the second embodiment, while part of the transmission phase of each sensor differs from that of the second embodiment. An object detection system according to the present embodiment is described below with reference to Fig. 11 described.

[0084] In this embodiment, as in the sixth and seventh embodiments, a first phase, a second phase and a third phase are used.

[0085] In Fig. Sensor 11, which transmits test waves in the first phase, is indicated by a triangle; sensor 11, which transmits test waves in the second phase, is indicated by a circle; and sensor 21, which transmits test waves in the third phase, is indicated by a square. That is, the first front sensor 31, the fourth front sensor 34, the first rear sensor 41, and the fourth rear sensor 44 are designated to transmit test waves in the first phase; the third front sensor 33, the second rear sensor 42, the first left-side sensor 51, and the second right-side sensor 62 are designated to transmit test waves in the second phase; and the second front sensor 32, the third rear sensor 43, the second left-side sensor 52, and the first right-side sensor 61 are designated to transmit test waves in the third phase.

[0086] By defining this phase, the phase transmitted by each sensor and the phases transmitted by each of its neighboring sensors are distinct. Therefore, even if test waves are transmitted by any one sensor and its neighboring sensors, it is possible to determine that received waves are the reflected waves of the test waves from that specific sensor. This means that even if test waves are emitted essentially simultaneously by all sensors, each sensor can determine which sensor emitted the test waves of the reflected waves that constitute these received waves.

[0087] It would be equally possible, as in Fig. Figure 12 shows a configuration in which the first front sensor 31, the third front sensor 33, the first right-side sensor 61, the second rear sensor 42, the fourth rear sensor 44, and the second left-side sensor 52 are configured to transmit test waves in the first phase (transmission characteristic), while the second front sensor 32, the fourth front sensor 34, the first rear sensor 41, the third rear sensor 43, the first left-side sensor 51, and the second right-side sensor 62 are configured to transmit test waves in the second phase (transmission characteristic). In this configuration, the second front sensor 32, the third front sensor 33, the second rear sensor 42, and the third rear sensor 43 can be omitted, or the first left-side sensor 51, the second left-side sensor 52, the first right-side sensor 61, and the second right-side sensor 62 can be omitted.This means that at least eight sensors (object detection devices) are provided adjacent to each other on the outer circumference of the vehicle, with the transmission characteristics of adjacent sensors being different. <Neuntes Ausführungsbeispiel>

[0088] In this embodiment, the overall configuration of the object recognition system is the same as that of the second embodiment, while part of the processing differs from that of the second embodiment. The processing performed in the present embodiment is described below with reference to Fig. 13 described.

[0089] In the present embodiment, the first setting mode (shown in Fig. 13(a)) and the second setting mode (shown in Fig. 13(b)) by switching between the same.

[0090] In the first setup mode, as in Fig. As shown in Figure 13(a), the second front sensor 32, the third rear sensor 43, the second left-side sensor 52, and the first right-side sensor 61 are configured to generate test waves in the first phase. The third front sensor 33, the second rear sensor 42, the first left-side sensor 51, and the second right-side sensor 62 are configured to transmit the test waves in the second phase. The first front sensor 31, the fourth front sensor 34, the first rear sensor 41, and the fourth rear sensor 44, shown in dashed lines, do not transmit test waves.

[0091] In the second setting mode, as in Fig. As shown in Figure 13(b), the sensors that transmit test waves in the first setting mode do not transmit test waves, while the sensor that does not transmit test waves in the first setting mode does transmit test waves. That is, the fourth front sensor 34 and the first rear sensor 41 are configured to transmit test waves in the first phase, while the first front sensor 31 and the fourth rear sensor 44 are configured to transmit test waves in the second phase. The second front sensor 32, the third front sensor 33, the second rear sensor 42, the third rear sensor 43, the first left-side sensor 51, the second left-side sensor 52, the first right-side sensor 61, and the second right-side sensor 62 do not transmit test waves.

[0092] The switch between the first and second setting modes occurs at each of predefined periods. The predefined period can be a period in which the transmitter-receiver control is executed once for each sensor, or it can be a period in which the transmitter-receiver control is executed multiple times for each sensor.

[0093] An object recognition system according to the present embodiment with the above configuration exhibits the following effects.

[0094] For example, in the sensor group on the left front of the vehicle, the second front sensor 32 and the first left-side sensor 51, each with different transmission characteristics, are arranged at a distance from each other. Therefore, based on the reception characteristics detected by this sensor, the first front sensor 31 can determine that received waves with these characteristics are reflected waves of test waves transmitted by the second front sensor 32 or the first left-side sensor 51. This also applies to the right front sensor group, the left rear sensor group, and the right rear sensor group of the vehicle.

[0095] Since the transmission frequency is switched at predetermined times or periods, the transmission frequency of the test waves of each of the ultrasonic sensors can deviate from or be made different from the transmission frequencies of the test waves of the other ultrasonic sensors, and interference can thus be suppressed.

[0096] The same effects are observed as in the first embodiment. <Zehntes Ausführungsbeispiel>

[0097] In this embodiment, the overall configuration of the object recognition system is the same as in the second embodiment, while part of the processing differs from that of the second embodiment. The processing performed in the present embodiment is described below with reference to [reference to...]. Fig. 14 described.

[0098] In the present embodiment, the first setting mode (shown in Fig. 14(a)) and the second setting mode (shown in Fig. 14(b)) by switching between the same.

[0099] As in Fig. As shown in 14(a), the first setting mode is the same as in Fig. 13(a) of the ninth embodiment.

[0100] In the second setting mode, as in Fig. As shown in Figure 14(b), the first right-hand sensor 61 transmits, in addition to the setting mode, which is the same as in Figure 14(b). Fig. 13(b) of the ninth embodiment, test waves in the second phase. The second right-hand sensor 62 is configured to transmit test waves in the first phase. That is, the first left-hand sensor 51, the second left-hand sensor 52, the first right-hand sensor 61, and the second right-hand sensor 62 always emit test waves.

[0101] An object detection system according to the present embodiment with the configuration described above provides similar effects to those of the ninth embodiment. Furthermore, since the first left-side sensor 51, the second left-side sensor 52, the first right-side sensor 61, and the second right-side sensor 62 always transmit or emit test waves, objects located laterally can always be detected or captured. <Elftes Ausführungsbeispiel>

[0102] In this embodiment, the overall configuration of the object recognition system is the same as that of the second embodiment, while part of the processing differs from that of the second embodiment. The processing performed in the present embodiment is described below with reference to Fig. 15 described.

[0103] In the present embodiment, the first setting mode (shown in Fig. 15(a)) and the second setting mode (shown in Fig. 15(b)) by switching between the same.

[0104] In the first setup mode, as in Fig. As shown in Figure 15(a), the first front sensor 31, the fourth rear sensor 44, the second left-side sensor 52, and the first right-side sensor 61 are configured to transmit test waves in the first phase. The third front sensor 33 and the second rear sensor 42 are configured to transmit test waves in the second phase. The second front sensor 32, the fourth front sensor 34, the first rear sensor 41, the third rear sensor 43, the first left-side sensor 51, and the second right-side sensor 62, each represented by dashed lines, do not transmit test waves.

[0105] In the second setting mode, as in Fig. As shown in Figure 15(b), each sensor that emits test waves in the first setting mode does not transmit test waves, while each sensor that does not emit test waves in the first setting mode does transmit test waves. That is, the second front sensor 32 and the second right-side sensor 62 are configured to transmit test waves in the first phase, and the fourth front sensor 34 and the first left-side sensor 51 are configured to transmit test waves in the second phase. The first front sensor 31, the third front sensor 33, the second rear sensor 42, the fourth rear sensor 44, the second left-side sensor 52, and the first right-side sensor 61, each represented by dashed lines, do not transmit test waves.

[0106] The switch between the first and second setting modes occurs at each of predefined periods. The predefined period can be a period in which the transmitter-receiver control is executed once for each sensor, or it can be a period in which the transmitter-receiver control is executed multiple times for each sensor.

[0107] An object recognition system according to the present embodiment with the above configuration has the following effects.

[0108] For example, in the sensor group at the front of the vehicle, the second front sensor 32 and the first left-side sensor 51, each with different transmission characteristics, are spaced apart from each other. Therefore, the first front sensor 31 can determine, based on the reception characteristics it detects, that received waves with these characteristics are reflected waves of test waves transmitted by the second front sensor 32 or the first left-side sensor 51. The third front sensor 33 can determine, based on the reception characteristics it detects, that received waves with these characteristics are reflected waves of test waves transmitted by the second front sensor 32 or the fourth front sensor 34. This also applies to the sensor group at the rear of the vehicle.

[0109] Since the transmission frequency is switched at each of the prescribed periods, the transmission frequency of the test waves of each of the ultrasonic sensors can differ from the transmission frequencies of the test waves of the other ultrasonic sensors, and thus interference can be suppressed.

[0110] The same effects are observed as in the first embodiment. <Zwölftes Ausführungsbeispiel>

[0111] In this embodiment, the overall configuration of the object recognition system is the same as that of the second embodiment, while part of the processing differs from that of the second embodiment. The processing performed in the present embodiment is described below with reference to Fig. 16 described.

[0112] In the present embodiment, the first setting mode (shown in Fig. 16(a)) and the second setting mode (shown in Fig. 16(b)) by switching between the same.

[0113] In the first setup mode, as in Fig. 16(a) shown, in addition to the setting mode, which is the same as in Fig. 15(a) of the eleventh embodiment, the first left sensor 51 and the second right sensor 62 are specified to transmit test waves in the second phase.

[0114] In the second setting mode, as in Fig. As shown in 16(b), in addition to the setting mode, which is the same as in Fig. In paragraph 15(b) of the eleventh embodiment, the second left-hand sensor 52 and the first right-hand sensor 61 are specified to transmit test waves in the first phase. That is, the first left-hand sensor 51, the second left-hand sensor 52, the first right-hand sensor 61, and the second right-hand sensor 62 always transmit test waves.

[0115] An object detection system according to the present embodiment with the configuration described above provides similar effects to that of the eleventh embodiment. Furthermore, since the first left-side sensor 51, the second left-side sensor 52, the first right-side sensor 61, and the second right-side sensor 62 always transmit test waves, objects located laterally can always be detected. <modifikationen>

[0116] Each of the embodiments involves switching the phase of the test waves; however, it would also be possible to switch the frequency of the test waves instead of the phase. In this case, the frequency of the test waves can also be described as a transmit or transmission characteristic and a receive characteristic, just like the phase.

[0117] In each of the embodiments, the phase switching of the test waves is performed; however, it would be possible to provide off-periods during which the phase switching of the test waves is not carried out. In this case, providing these off-periods will generate a multitude of peak values ​​in the amplitude envelope of the test waves. If such a multitude of amplitude envelope peaks is generated, a multitude of peaks will also be generated in the amplitude envelope of the reflected waves, making it possible to determine whether received waves are reflected waves of test waves. It should be noted that the number of peak values ​​of the amplitude envelope can also be referred to as the transmission characteristic and the reception characteristic, as with the phase.

[0118] In the exemplary embodiments, the length of the shutdown period is a product of a predetermined value and the period of the test wave signal. In this context, it would also be possible to make the length of the shutdown period longer than the time it takes for the amplitude of the test waves to fall below a first predetermined threshold, and shorter than the time it takes for the amplitude of the test waves to fall below a second predetermined threshold if the second predetermined threshold is lower than the first. If the length is made longer than the time it takes for the amplitude of the test waves to fall below the first predetermined threshold, the amplitude at the beginning of the test wave transmission after the switching of the transmission characteristics is sufficiently small, and an adequate capacitor charging time can be ensured.If the length of the shutdown period is made shorter than the time that elapses until the amplitude of the test waves falls below the second predetermined threshold, the length of a single transmission opportunity can be limited and a sufficient length of period or time span during which received waves are received can be ensured.

[0119] In the second to fifth embodiments, the differentiation of received waves is achieved by using sensors that transmit test waves with a phase change, and also sensors that transmit the test waves without a phase change. It would also be possible to achieve the differentiation by having each of the sensors perform a phase change, using a first phase and / or a second phase that differ from each other as the changed phase.

[0120] In embodiments six through eight, differentiation is achieved by performing the phase change on each of the sensors and by using the first through third phases, which differ from each other, as the changed phases. It would also be possible to achieve differentiation by using sensors that do not change the phase, as well as sensors that transmit with a first or second phase as the changed phase.

[0121] Although the invention has been described by means of examples, it is understood that the invention is not limited to these examples and structures. The invention also includes various modifications and variations, which are subject to an equivalent scope of protection. Furthermore, various combinations and forms, including combinations and forms containing one or more elements, also fall within the scope of protection of the invention.< / modifikationen>

Claims

[1] Ultrasonic sensor (10) for transmitting a test wave signal from test waves at each transmission time, comprising: a transmission section (14) which includes a piezoelectric element (141) and is configured such that the piezoelectric element (141) oscillates based on electrical energy supplied to it in order to transmit the test wave signal; a transmission circuit (13) that supplies the electrical energy to the piezoelectric element (141); and a transmission control section (12) that is configured to: Driving the transmission circuit (13) for each transmission time to cause the transmission section (14) to send the test wave signal; Switching from a first transmission characteristic of the test wave signal to a second transmission characteristic when a predetermined interval has elapsed since the start of the transmission of the test wave signal, wherein each of the first and second transmission characteristics of the test wave signal includes at least a phase, a frequency, a period and an amplitude of the test wave signal; Setting a switch-off period to interrupt the supply of electrical energy from the transmission circuit (13) to the piezoelectric element (141) when switching from the first transmission characteristic of the test wave signal to the second transmission characteristic of the same; and Switching for each transmission time whether the shutdown period should be provided, whereby the shutdown period is provided in at least one of the transmission times and is not provided in at least one other of the transmission times. [2] Ultrasonic sensor (10) according to claim 1, wherein: the transfer circuit (13) includes a capacitor (137) and is configured to supply the charge stored in the capacitor (137) to the piezoelectric element (141) as electrical energy. [3] Ultrasonic sensor (10) according to claim 1 or claim 2, wherein: the length of the shutdown period is longer than a first length, which is a product of a first predetermined value and the period of the test wave signal, and shorter than a second length, which is a product of a second predetermined value and the period of the test wave signal. [4] Ultrasonic sensor (10) according to claim 3, wherein: the first predetermined value is 4. [5] Ultrasonic sensor (10) according to claim 1 or claim 2, wherein: the length of the shutdown period is longer than the time it takes for the amplitude of the test wave signal to fall below a first predetermined threshold, and shorter than the time it takes for the amplitude of the test wave signal to fall below a second predetermined threshold, where the second predetermined threshold is smaller than the first predetermined threshold. [6] Object detection system installed on a vehicle, wherein the object detection system comprises a plurality of ultrasonic sensors (10), each of which is the ultrasonic sensor (10) according to any one of claims 1 to 5, wherein: the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section that receives a received wave signal which includes reflected waves based on the respective test waves, The object recognition system includes: a characteristic detection section (18) which detects a receiving characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the receiving characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal, and the ultrasonic sensors (10) include: four ultrasonic sensors (31 to 34) are provided at a front end of the vehicle as first, second, third and fourth front sensors (31 to 34), wherein the first to fourth front sensors (31 to 34) are arranged sequentially from left to right at intervals from each other, four ultrasonic sensors (41 to 44) are provided at a rear end of the vehicle as first, second, third and fourth rear sensors (41 to 44), wherein the first to fourth rear sensors (41 to 44) are arranged sequentially from left to right at intervals from each other, two ultrasonic sensors (51, 52) are provided on a left side of the vehicle as first and second left-side sensors (51, 52), wherein the first and second left-side sensors (51, 52) are arranged sequentially from front to rear at intervals from each other, two ultrasonic sensors (61, 62) are provided on a right side of the vehicle as first and second right-side sensors (61, 62), wherein the first and second right-side sensors (61, 62) are arranged sequentially from front to rear at intervals from each other, wherein Each of the ultrasonic sensors (10) is configured to switch the transmission characteristic between a first setting mode and a second setting mode at predetermined intervals, Each of the first to fourth front sensors (31 to 34) and the first to fourth rear sensors (41 to 44) is configured to operate in the first setting mode to transmit the test wave signal with a first transmission characteristic as the transmission characteristic, Each of the first and second left-hand sensors (51, 52) and the first and second right-hand sensors (61, 62) is configured to operate in the first setting mode to transmit the test wave signal with a second transmission characteristic that differs from the first transmission characteristic. Each of the first to fourth front sensors (31 to 34) and the first to fourth rear sensors (41 to 44) is configured to operate in the second setting mode to transmit the test wave signal with the second transmission characteristic as the transmission characteristic, Each of the first and second left-hand sensors (51, 52) and the first and second right-hand sensors (61, 62) is configured to operate in the second setting mode to transmit the test wave signal with the first transmission characteristic as the transmission characteristic, and the object recognition system includes a determination section (23) which determines which of the ultrasonic sensors (10) has transmitted the test signal corresponding to the received wave signal, the receiving characteristic of which is detected by the characteristic detection section (18). [7] Object detection system installed on a vehicle and comprising: a plurality of ultrasonic sensors (10), each of which is configured to transmit a test wave signal of test waves at each transmission time, wherein Each of the ultrasonic sensors (10) includes: a transmission section (14) which includes a piezoelectric element (141) and is configured such that the piezoelectric element (141) oscillates based on electrical energy supplied to it in order to transmit the test wave signal; a transmission circuit (13) that supplies the electrical energy to the piezoelectric element (141); a transmission control section (12) that is configured to: Driving the transmission circuit (13) for each transmission time to cause the transmission section (14) to send the test wave signal; Switching from a first transmission characteristic of the test wave signal to a second transmission characteristic when a predetermined interval has elapsed since the start of the transmission of the test wave signal, wherein each of the first and second transmission characteristics of the test wave signal includes at least one phase, one frequency, one period and one amplitude of the test wave signal; Setting a switch-off period to interrupt the supply of electrical energy from the transmission circuit (13) to the piezoelectric element (141) when switching from the first transmission characteristic of the test wave signal to the second transmission characteristic of the same; and Switching for each transmission time whether the shutdown period should be provided, whereby the shutdown period is provided in at least one of the transmission times and is not provided in at least one other of the transmission times; a characteristic detection section (18) which detects a receiving characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the receiving characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal, wherein the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section which receives a received wave signal which includes reflected waves based on the respective test waves, the ultrasonic sensors (10) include: four ultrasonic sensors (31 to 34) are provided at a front end of the vehicle as first, second, third and fourth front sensors (31 to 34), wherein the first to fourth front sensors (31 to 34) are arranged sequentially from left to right at intervals from each other, four ultrasonic sensors (41 to 44) are provided at a rear end of the vehicle as first, second, third and fourth rear sensors (41 to 44), wherein the first to fourth rear sensors (41 to 44) are arranged sequentially from left to right at intervals from each other, two ultrasonic sensors (51, 52) are provided on a left side of the vehicle as first and second left-side sensors (51, 52), wherein the first and second left-side sensors (51, 52) are arranged sequentially from front to rear at intervals from each other, two ultrasonic sensors (61, 62) are provided on a right side of the vehicle as first and second right-side sensors (61, 62), wherein the first and second right-side sensors (61, 62) are arranged sequentially from front to rear at intervals from each other, Each of the ultrasonic sensors (10) is configured to switch the transmission characteristic between a first setting mode and a second setting mode at predetermined intervals, Each of the first to fourth front sensors (31 to 34) and the first to fourth rear sensors (41 to 44) is configured to operate in the first setting mode to transmit the test wave signal with a first transmission characteristic as the transmission characteristic, Each of the first and second left-hand sensors (51, 52) and the first and second right-hand sensors (61, 62) is configured to operate in the first setting mode to transmit the test wave signal with a second transmission characteristic that differs from the first transmission characteristic. Each of the first to fourth front sensors (31 to 34) and the first to fourth rear sensors (41 to 44) is configured to operate in the second setting mode to transmit the test wave signal with the second transmission characteristic as the transmission characteristic, Each of the first and second left-hand sensors (51, 52) and the first and second right-hand sensors (61, 62) is configured to operate in the second setting mode to transmit the test wave signal with the first transmission characteristic as the transmission characteristic, and the object recognition system includes a determination section (23) which determines which of the ultrasonic sensors (10) has transmitted the test signal corresponding to the received wave signal, the receiving characteristic of which is detected by the characteristic detection section (18). [8] Object detection system with a plurality of ultrasonic sensors (10) according to any one of claims 1 to 5, which is installed on a vehicle, wherein: the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section that receives a received wave signal which includes reflected waves based on the respective test waves, The object recognition system includes: a characteristic detection section (18) which detects a receiving characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the receiving characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal, the ultrasonic sensors (10) include: four ultrasonic sensors (31 to 34) are provided at a front end of the vehicle as first, second, third and fourth front sensors (31 to 34), wherein the first to fourth front sensors (31 to 34) are arranged sequentially from left to right at intervals from each other, four ultrasonic sensors (41 to 44) are provided at a rear end of the vehicle as first, second, third and fourth rear sensors (41 to 44), wherein the first to fourth rear sensors (41 to 44) are arranged sequentially from left to right at intervals from each other, two ultrasonic sensors (51, 52) are provided on a left side of the vehicle as first and second left-side sensors (51, 52), wherein the first and second left-side sensors (51, 52) are arranged sequentially from front to rear at intervals from each other, two ultrasonic sensors (61, 62) are provided on a right side of the vehicle as first and second right-side sensors (61, 62), wherein the first and second right-side sensors (61, 62) are arranged sequentially from front to rear at intervals from each other, Each of the first to fourth front sensors (31 to 34) and the first to fourth rear sensors (41 to 44) is configured to transmit the test wave signal with a first transmission characteristic as the transmission characteristic, Each of the third front sensor (33), the second rear sensor (42), the first left-side sensor (51) and the second right-side sensor (62) is configured to transmit the test wave signal with a second transmission characteristic that differs from the first transmission characteristic. each of the second front sensor (32), the third rear sensor (43), the second left-side sensor (52) and the first right-side sensor (61) is configured to transmit the test wave signal with a third transmission characteristic than the transmission characteristic, wherein the third transmission characteristic differs from the first and the second transmission characteristics; and the object recognition system includes a determination section (23) which determines which of the ultrasonic sensors (10) has transmitted the test signal corresponding to the received wave signal, the receiving characteristic of which is detected by the characteristic detection section (18). [9] Object detection system with a plurality of ultrasonic sensors (10) according to any one of claims 1 to 5, installed on a vehicle, wherein: the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section that receives a received wave signal which includes reflected waves based on the respective test waves, The object recognition system includes: a characteristic detection section (18) which detects a receiving characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the receiving characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal, the ultrasonic sensors (10) include: four ultrasonic sensors (31 to 34) are provided at a front end of the vehicle as first, second, third and fourth front sensors (31 to 34), wherein the first to fourth front sensors (31 to 34) are arranged sequentially from left to right at intervals from each other, four ultrasonic sensors (41 to 44) are provided at a rear end of the vehicle as first, second, third and fourth rear sensors (41 to 44), wherein the first to fourth rear sensors (41 to 44) are arranged sequentially from left to right at intervals from each other, two ultrasonic sensors (51, 52) are provided on a left side of the vehicle as first and second left-side sensors (51, 52), wherein the first and second left-side sensors (51, 52) are arranged sequentially from front to rear at intervals from each other, two ultrasonic sensors (61, 62) are provided on a right side of the vehicle as first and second right-side sensors (61, 62), wherein the first and second right-side sensors (61, 62) are arranged sequentially from front to rear at intervals from each other, Each of the ultrasonic sensors (10) is configured to switch the transmission characteristic between a first setting mode and a second setting mode at predetermined intervals, Each of the second front sensor (32), the third rear sensor (43), the second left-side sensor (52) and the first right-side sensor (61) is configured to operate in the first setting mode to transmit the test wave signal with a first transmission characteristic as the transmission characteristic, Each of the third front sensor (33), the second rear sensor (42), the first left-side sensor (51) and the second right-side sensor (62) is configured to operate in the first setting mode to transmit the test wave signal with a second transmission characteristic that differs from the first transmission characteristic. Each of the fourth front sensor (34) and the first rear sensor (41) is configured to operate in the second setting mode to transmit the test wave signal with the first transmission characteristic as the transmission characteristic, Each of the first front sensor (31) and the fourth rear sensor (44) is configured to operate in the second setting mode to transmit the test wave signal with the second transmission characteristic as the transmission characteristic; and the object recognition system includes a determination section (23) which determines which of the ultrasonic sensors (10) has transmitted the test signal corresponding to the received wave signal, the receiving characteristic of which is detected by the characteristic detection section (18). [10] Object detection system installed on a vehicle, wherein the object detection system comprises a plurality of ultrasonic sensors (10), each of which is the ultrasonic sensor (10) according to any one of claims 1 to 5, wherein: the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section that receives a received wave signal which includes reflected waves based on the respective test waves, The object recognition system includes: a characteristic detection section (18) which detects a receiving characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the receiving characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal, the ultrasonic sensors (10) include: four ultrasonic sensors (31 to 34) are provided at a front end of the vehicle as first, second, third and fourth front sensors (31 to 34), wherein the first to fourth front sensors (31 to 34) are arranged sequentially from left to right at intervals from each other, four ultrasonic sensors (41 to 44) are provided at a rear end of the vehicle as first, second, third and fourth rear sensors (41 to 44), wherein the first to fourth rear sensors (41 to 44) are arranged sequentially from left to right at intervals from each other, two ultrasonic sensors (51, 52) are provided on a left side of the vehicle as first and second left-side sensors (51, 52), wherein the first and second left-side sensors (51, 52) are arranged sequentially from front to rear at intervals from each other, two ultrasonic sensors (61, 62) are provided on a right side of the vehicle as first and second right-side sensors (61, 62), wherein the first and second right-side sensors (61, 62) are arranged sequentially from front to rear at intervals from each other, Each of the ultrasonic sensors (10) is configured to switch the transmission characteristic between a first setting mode and a second setting mode at predetermined intervals, Each of the second front sensor (32), the third rear sensor (43), the second left-side sensor (52) and the first right-side sensor (61) is configured to operate in the first setting mode to transmit the test wave signal with a first transmission characteristic as the transmission characteristic, Each of the third front sensor (33), the second rear sensor (42), the first left-side sensor (51) and the second right-side sensor (62) is configured to operate in the first setting mode to transmit the test wave signal with a second transmission characteristic that differs from the first transmission characteristic. Each of the fourth front sensor (34), the first rear sensor (41), the second left-side sensor (52) and the second right-side sensor (62) is configured to operate in the second setting mode to transmit the test wave signal with the first transmission characteristic as the transmission characteristic, Each of the first front sensor (31), the fourth rear sensor (44), the first left-side sensor (51) and the first right-side sensor (61) is configured to operate in the second setting mode to transmit the test wave signal with the second transmission characteristic as the transmission characteristic; and the object recognition system includes a determination section (23) which determines which of the ultrasonic sensors (10) has transmitted the test signal corresponding to the received wave signal, the receiving characteristic of which is detected by the characteristic detection section (18). [11] Object detection system installed on a vehicle, wherein the object detection system comprises a plurality of ultrasonic sensors (10), each of which is the ultrasonic sensor (10) according to any one of claims 1 to 5, wherein: the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section that receives a received wave signal which includes reflected waves based on the respective test waves, The object recognition system includes: a characteristic detection section (18) which detects a receiving characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the receiving characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal, the ultrasonic sensors (10) include: four ultrasonic sensors (31 to 34) are provided at a front end of the vehicle as first, second, third and fourth front sensors (31 to 34), wherein the first to fourth front sensors (31 to 34) are arranged sequentially from left to right at intervals from each other, four ultrasonic sensors (41 to 44) are provided at a rear end of the vehicle as first, second, third and fourth rear sensors (41 to 44), wherein the first to fourth rear sensors (41 to 44) are arranged sequentially from left to right at intervals from each other, two ultrasonic sensors (51, 52) are provided on a left side of the vehicle as first and second left-side sensors (51, 52), wherein the first and second left-side sensors (51, 52) are arranged sequentially from front to rear at intervals from each other, two ultrasonic sensors (61, 62) are provided on a right side of the vehicle as first and second right-side sensors (61, 62), wherein the first and second right-side sensors (61, 62) are arranged sequentially from front to rear at intervals from each other, Each of the ultrasonic sensors (10) is configured to switch the transmission characteristic between a first setting mode and a second setting mode at predetermined intervals, Each of the first front sensor (31), the fourth rear sensor (44), the second left-side sensor (52) and the first right-side sensor (61) is configured to operate in the first setting mode to transmit the test wave signal with a first transmission characteristic as the transmission characteristic, Each of the third front sensor (33) and the second rear sensor (42) is configured to operate in the first setting mode to transmit the test wave signal with a second transmission characteristic that differs from the first transmission characteristic. Each of the second front sensor (32), the first rear sensor (41) and the second right-side sensor (62) is configured to operate in the second setting mode to transmit the test wave signal with the first transmission characteristic as the transmission characteristic, Each of the fourth front sensor (34), the third rear sensor (43) and the first left-side sensor (51) is configured to operate in the second setting mode to transmit the test wave signal with the second transmission characteristic as the transmission characteristic; and the object recognition system includes a determination section (23) which determines which of the ultrasonic sensors (10) has transmitted the test signal corresponding to the received wave signal, the receiving characteristic of which is detected by the characteristic detection section (18). [12] Object detection system installed on a vehicle, wherein the object detection system comprises a plurality of ultrasonic sensors (10), each of which is the ultrasonic sensor (10) according to any one of claims 1 to 5, wherein: the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section that receives a received wave signal which includes reflected waves based on the respective test waves, The object recognition system includes: a characteristic detection section (18) which detects a receiving characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the receiving characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal, the ultrasonic sensors (10) include: four ultrasonic sensors (31 to 34) are provided at a front end of the vehicle as first, second, third and fourth front sensors (31 to 34), wherein the first to fourth front sensors (31 to 34) are arranged sequentially from left to right at intervals from each other, four ultrasonic sensors (41 to 44) are provided at a rear end of the vehicle as first, second, third and fourth rear sensors (41 to 44), wherein the first to fourth rear sensors (41 to 44) are arranged sequentially from left to right at intervals from each other, two ultrasonic sensors (51, 52) are provided on a left side of the vehicle as first and second left-side sensors (51, 52), wherein the first and second left-side sensors (51, 52) are arranged sequentially from front to rear at intervals from each other, two ultrasonic sensors (61, 62) are provided on a right side of the vehicle as first and second right-side sensors (61, 62), wherein the first and second right-side sensors (61, 62) are arranged sequentially from front to rear at intervals from each other, Each of the ultrasonic sensors (10) is configured to switch the transmission characteristic between a first setting mode and a second setting mode at predetermined intervals, Each of the first front sensor (31), the fourth rear sensor (44), the second left-side sensor (52) and the first right-side sensor (61) is configured to operate in the first setting mode to transmit the test wave signal with a first transmission characteristic as the transmission characteristic, Each of the third front sensor (33), the second rear sensor (42), the first left-side sensor (51) and the second right-side sensor (62) is configured to operate in the first setting mode to transmit the test wave signal with a second transmission characteristic that differs from the first transmission characteristic. Each of the second front sensor (32), the first rear sensor (41), the second left-side sensor (52) and the first and second right-side sensors (61, 62) is configured to operate in the second setting mode to transmit the test wave signal with the first transmission characteristic as the transmission characteristic, Each of the fourth front sensor (34), the third rear sensor (43) and the first left-side sensor (51) is configured to operate in the second setting mode to transmit the test wave signal with the second transmission characteristic as the transmission characteristic; and the object recognition system includes a determination section (23) which determines which of the ultrasonic sensors (10) has transmitted the test signal corresponding to the received wave signal, the receiving characteristic of which is detected by the characteristic detection section (18). [13] Object recognition system according to any one of claims 6 to 12, wherein: at least one of the ultrasonic sensors (10) is arranged in such a way that it is able to: Receiving a direct wave signal from direct waves, which are received reflection waves corresponding to the test waves transmitted by at least one of the ultrasonic sensors (10), and Receiving an indirect wave signal from indirect waves, which are received reflection waves of the test waves transmitted by another of the ultrasonic sensors (10); wherein the transmission characteristics of the test wave signal transmitted by at least one of the ultrasonic sensors (10) and the transmission characteristics of the test wave signal transmitted by another of the ultrasonic sensors (10) are different from each other; and the determination section (23) is configured to determine, based on the reception characteristics, whether the received wave signal received by at least one of the ultrasonic sensors (10) is the direct wave signal or the indirect wave signal. [14] Object recognition system according to any one of claims 6 to 13, wherein: at least one of the ultrasonic sensors (10) is arranged in such a way that it is able to: Receiving an indirect wave signal from indirect waves, which are received reflection waves corresponding to the test waves transmitted by other sensors in the ultrasonic sensors (10), wherein the other sensors each have different transmission characteristics; and the determination section (23) is configured to determine, based on the reception characteristics, which of the other sensors transmitted the indirect wave signal received by at least one of the ultrasonic sensors (10). [15] Object detection system installed on a vehicle comprising a plurality of ultrasonic sensors (10), each of which is the ultrasonic sensor (10) according to any one of claims 1 to 5, wherein the transmission section (14) of each of the ultrasonic sensors (10) operates as a transmitter-receiver section that receives a received wave signal which includes reflected waves based on the respective test waves, The object recognition system includes: a characteristic detection section (18) that detects a reception characteristic of a received wave signal transmitted by one of the ultrasonic sensors (10), wherein the reception characteristic of the at least one received wave signal includes at least one phase, frequency, period and amplitude of the at least one received signal; and a defining section (23) which determines that the received wave signal received by at least one of the ultrasonic sensors (10) corresponds to the test wave signal transmitted by one of the other ultrasonic sensors (10), wherein each of the ultrasonic sensors (10) is configured to switch the transmission characteristic to a different transmission characteristic at each predetermined interval. [16] Object recognition system according to claim 15, wherein: the ultrasonic sensors (10) include a right-side sensor (61, 62) provided on the right side of the vehicle and a left-side sensor (51, 52) provided on the left side of the vehicle; and the transmission characteristic of the right-side sensor (61, 62) differs from the transmission characteristic of the left-side sensor (51, 52). [17] Object recognition system according to claim 15, wherein: the ultrasonic sensors (10) include a front sensor (31 to 34) provided at a front end of the vehicle and a rear sensor (41 to 44) provided at a rear end of the vehicle; and the transmission characteristics of the front sensor (31 to 34) differ from the transmission characteristics of the rear sensor (41 to 44). [18] Object recognition system according to claim 15, wherein: the ultrasonic sensors (10) include at least one set of adjacent ultrasonic sensors (31-34, 51, 61, 41-44, 52, 62) which are arranged adjacent to each other, wherein the adjacent ultrasonic sensors (31-34, 51, 61, 41-44, 52, 62) of the at least one set each have different transmission characteristics. [19] Object recognition system according to claim 18, wherein: the adjacent ultrasonic sensors (31-34, 51, 61, 41-44, 52, 62) include: at least two front sensors (31-34) arranged adjacent to each other at a front end of the vehicle, wherein the transmission characteristics of the at least two adjacent front sensors (31-34) differ from each other; and at least two rear sensors (41-44) arranged adjacent to each other at a rear end of the vehicle, wherein the transmission characteristics of the at least two adjacent rear sensors (41-44) differ from each other. [20] Object recognition system according to claim 18 or claim 19, wherein: the adjacent ultrasonic sensors (31-34, 51, 61, 41-44, 52, 62) include: at least two left-side sensors (51, 52) arranged adjacent to each other on the left side of the vehicle, wherein the transmission characteristics of the at least two left-side sensors (51, 52) that are adjacent to each other differ from each other; and at least two right-side sensors (61, 62) arranged adjacent to each other on the right side of the vehicle, wherein the transmission characteristics of the at least two right-side sensors (61, 62) which are adjacent to each other differ from each other. [21] Object recognition system according to any one of claims 18 to 20, wherein: the ultrasonic sensors (10) include at least eight ultrasonic sensors (31-34, 41-44, 51, 52, 61, 62) arranged sequentially on an outer circumference of the vehicle, wherein each adjacent pair of the eight ultrasonic sensors (31-34, 41-44, 51, 52, 61, 62) has the respective transmission characteristics which differ from each other. [22] Object recognition system according to claim 15, wherein: the ultrasonic sensors (10) are arranged apart from each other, wherein the ultrasonic sensors (31-34, 51, 61, 41-44, 52, 62) have the respective transmission characteristics which differ from each other.

Images