Drive device, ultrasonic sensor, and vehicle

Abstract

To provide a drive device capable of detecting a state of a signal path.SOLUTION: A drive device (1) drives an ultrasonic sensor element (2) via a transformer (Tr). The drive device comprises: a current driver (12) for supplying a first current to the transformer during a drive period to drive the ultrasonic sensor element for distance measurement, and supplying a second current smaller than the first current to the transformer during a state detection period not overlapping with the drive period; and a detection circuit (168) for detecting a state of a signal path including the ultrasonic sensor element and the transformer based on a terminal voltage of the ultrasonic sensor element during the state detection period.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a drive unit, an ultrasonic sensor, and a vehicle. [Background technology]

[0002] An ultrasonic sensor generates ultrasonic waves, measures the time it takes for the ultrasonic waves to hit an object and return to the ultrasonic sensor, and uses the measured time to determine the distance from the ultrasonic sensor to the object (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-35323 A

[0004] [overview] The ultrasonic sensor determines that an object does not exist when the reflected wave is not returned, so even if the ultrasonic sensor is broken or the characteristics of the ultrasonic sensor are fluctuating and the reflected wave cannot be received, the ultrasonic sensor may determine that an object does not exist.

[0005] The driving device according to the present disclosure is a driving device configured to drive an ultrasonic sensor element via a transformer, and includes a current driver configured to supply a first current to the transformer during a driving period for driving the ultrasonic sensor element for distance measurement, and to supply a second current smaller than the first current to the transformer during a state detection period that does not overlap with the driving period, and a detection circuit configured to detect a state of a signal path including the ultrasonic sensor element and the transformer based on a terminal voltage of the ultrasonic sensor element during the state detection period.

[0006] An ultrasonic sensor according to the present disclosure includes the drive device configured as described above, the ultrasonic sensor element, and the transformer.

[0007] A vehicle according to the present disclosure includes an ultrasonic sensor having the above-described configuration. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a vehicle equipped with an ultrasonic sensor according to an embodiment and an object. [Diagram 2] FIG. 2 is a diagram showing the configuration of the ultrasonic sensor according to the embodiment. [Diagram 3] FIG. 3 is a perspective view of the external appearance of the signal processing device. [Figure 4] FIG. 4 is a diagram showing an equivalent circuit on the secondary side of a transformer. [Diagram 5] FIG. 5 is a diagram showing a schematic waveform of an output signal of the envelope portion during a state detection period. [Figure 6] FIG. 6 is a diagram showing impedance characteristics of the ultrasonic sensor element.

[0009] [Detailed Description] The ultrasonic sensor described below is assumed to be mounted on a vehicle as an example, and can be used for an alarm function, an automatic braking function, an automatic parking function, and the like by measuring the distance between the vehicle and an object.

[0010] 1 is a schematic diagram showing a vehicle 200 equipped with an ultrasonic sensor 100 according to an embodiment (hereinafter referred to as "ultrasonic sensor 100"), and an object (obstacle) 300. Ultrasonic waves transmitted from the ultrasonic sensor 100 are reflected by the object 300 and received by the ultrasonic sensor 100 as reflected waves.

[0011] FIG. 2 is a diagram showing the configuration of the ultrasonic sensor 100.

[0012] <Ultrasonic sensor> The ultrasonic sensor 100 includes a signal processing device 1, a transformer Tr, capacitors C1 and C2, and an ultrasonic sensor element 2. The ultrasonic sensor element 2 is externally connected to the signal processing device 1 via the transformer Tr and the capacitors C1 and C2. Note that the capacitors C1 and C2 are not necessarily provided.

[0013] The signal processing device 1 is both a driving device that drives the ultrasonic sensor element 2 via a transformer Tr, and a receiving device that receives reflected waves from an object (obstacle) 300. The signal processing device 1 is a semiconductor integrated circuit device. FIG. 3 is an external perspective view of the signal processing device 1. The signal processing device 1 is an electronic component formed by sealing a semiconductor integrated circuit chip in a housing (package) made of resin. A plurality of external terminals are exposed on the housing of the signal processing device 1, and the plurality of external terminals include terminals T1 to T5 shown in FIG. 2. Note that the number of external terminals of the signal processing device 1 and the external appearance of the signal processing device 1 shown in FIG. 3 are merely examples.

[0014] <Signal processing device> The signal processing device 1 includes a DAC (Digital to Analog Converter) 11, a current driver 12, an LNA (Low Noise Amplifier) ​​13, a PGA (Programmable Gain Amplifier) ​​14, an ADC (Analog to Digital Converter) 15, a digital processing unit 16, a reverberation period determination unit 17, and external terminals T1 to T5.

[0015] The DAC 11 performs D / A conversion on the transmission wave signal output from the transmission wave signal generating unit 161 included in the digital processing unit 16 from a digital signal to an analog signal, and outputs the D / A converted signal to the current driver 12 .

[0016] The output terminals of the differential pair of the current driver 12 are connected to the primary side of a transformer Tr via external terminals T1 and T2. A capacitor C T , resistance R T, and the ultrasonic sensor element 2 are connected. The current driver 12 supplies a current to the transformer Tr based on the output signal of the DAC 11 to drive the ultrasonic sensor element 2. The current supplied from the current driver 12 to the transformer Tr is a sink current. In other words, the current driver 12 sinks a current from the transformer Tr based on the output signal of the DAC 11 to drive the ultrasonic sensor element 2. The current driver 12 is configured to include, for example, a variable current source that varies the output current based on the analog signal output from the DAC 11, and a current sink type current mirror circuit that generates a mirror current corresponding to the output current of the variable current source.

[0017] The ultrasonic sensor element 2 has a piezoelectric element (not shown) and transmits and receives ultrasonic waves. In other words, the ultrasonic sensor element 2 is an ultrasonic transmission / reception device that functions as both a sound source and a receiver. The ultrasonic sensor element 2 may have a common piezoelectric element for transmitting and receiving waves, or may have a piezoelectric element dedicated to transmitting and a piezoelectric element dedicated to receiving waves.

[0018] The input terminals of the differential pair of the LNA13 are connected to the secondary side of the transformer Tr via external terminals T3 and T4 and capacitors C1 and C2. The LNA13 amplifies the differential signal received from the external terminals T3 and T4, converts it to a single-ended signal, and outputs it to the PGA14. The LNA13 also performs clipping so that the single-ended signal does not exceed a predetermined level. The PGA14 amplifies the signal received from the LNA13 and outputs it to the ADC15. The ADC15 A / D converts the output signal of the PGA14 from an analog signal to a digital signal, and outputs the A / D converted signal to the BPF162.

[0019] The digital processing unit 16 includes a control unit 160, a transmission signal generating unit 161, a BPF (Band Pass Filter) 162, an ABS (Absolute value processing unit) 163, an envelope unit 164, a reflected wave detecting unit 165, a TOF measuring unit 166, an interface 167, and a detection circuit 168. The digital processing unit 16 is formed of, for example, a digital signal processor.

[0020] The control unit 160 controls each part of the digital processing unit 16 based on commands received via an interface 167 from an ECU (Electronic Control Unit) (not shown) mounted on a vehicle 200 (see FIG. 1).

[0021] The transmission signal generating unit 161 is configured to generate a transmission signal for transmitting ultrasonic waves. More specifically, when the signal processing device 1 (particularly the control unit 160) receives a transmission command (distance measurement command) from an ECU (not shown) mounted on the vehicle 200 (see FIG. 1) via the interface 167, the transmission signal generating unit 161 generates a transmission signal including a predetermined number of waves in accordance with the control by the control unit 160, and outputs the transmission signal to the DAC11.

[0022] The BPF 162 passes only a predetermined frequency band of the output signal of the ADC 15 and attenuates frequency bands other than the predetermined frequency band. The BPF 162 has a frequency characteristic according to the frequency setting of the transmission signal. For example, the predetermined frequency band is set to match the frequency band of the transmission signal.

[0023] The ABS 163 performs absolute value processing on the output signal of the BPF 162. That is, the ABS 163 performs inversion processing on the negative output signal of the BPF 162 to convert it into a positive signal.

[0024] The envelope section 164 outputs a signal obtained by envelope detection of the output signal of the ABS 163 .

[0025] The reflected wave detection unit 165 detects a reflected wave when the sound pressure of the envelope detection signal output from the envelope unit 164 exceeds a threshold value. In order to prevent the reflected wave detection unit 165 from erroneously detecting the transmitted wave signal and the reverberation of the transmitted wave signal as a reflected wave, the threshold value used by the reflected wave detection unit 165 is set to a first set value until a predetermined time (a time when reverberation is assumed to disappear) has elapsed since the transmitted wave signal generation unit 161 received a wave transmission command (distance measurement command), and is then transitioned to a second set value smaller than the first set value.

[0026] The TOF measurement unit 166 uses the counter 166A to measure the time (TOF) from when an ultrasonic wave is transmitted until when the reflected wave reflected by the object 300 (see FIG. 1) is received.

[0027] The interface 167 is compliant with, for example, LIN (Local Interconnect Network) and communicates with an ECU (not shown) mounted on the vehicle 200 (see FIG. 1) via an external terminal T5.

[0028] The detection circuit 168 detects the state of the signal path including the ultrasonic sensor element 2 and the transformer Tr based on the terminal voltage of the ultrasonic sensor element 2 during the state detection period. More specifically, the detection circuit 168 detects the state of the signal path from the transmission signal generation unit 161 through the DAC 11, the current driver 12, the transformer Tr, the ultrasonic sensor element 2, the LNA 13, the PGA 14, the ADC 15, the BPF 162, the ABS 163, and the envelope unit 164 to the reflected wave detection unit 165 based on the envelope detection signal (a signal corresponding to the terminal voltage of the ultrasonic sensor element 2) during the state detection period.

[0029] The state detection period is a period that does not overlap with the drive period in which the signal processing device 1 drives the ultrasonic sensor element 2 for distance measurement. The current driver 12 supplies a first current to the transformer Tr during the drive period based on the output signal of the DAC 11, and supplies a second current smaller than the first current to the transformer Tr during the state detection period. That is, the wave transmission signal generating unit 161 generates a wave transmission signal having a different waveform during the drive period and during the state detection period. The number of waves included in the wave transmission signal generated by the wave transmission signal generating unit 161 during the state detection period is, for example, 20, and the duty of the wave transmission signal generated by the wave transmission signal generating unit 161 during the state detection period is, for example, 50%. The numerical values ​​(20 and 50%) of the number of waves and the duty are merely examples and are not limited to these numerical values. The crest value of the second current is, for example, 1 / 10 of the crest value of the first current. This crest value (1 / 10 of the crest value of the first current) is merely an example and is not limited to these numerical values.

[0030] The state detection period is provided, for example, from when the signal processing device 1 receives a distance measurement command until the drive period starts. Alternatively, a plurality of state detection periods may be provided, and the state detection period may be provided at a time other than when the distance measurement command is received until the drive period starts. For example, when the vehicle 200 (see FIG. 1) is equipped with a plurality of ultrasonic sensors 100 at different positions and the plurality of ultrasonic sensors 100 are caused to measure distances in a time-division manner, the state detection period of a certain ultrasonic sensor 100 may be provided so as to overlap with the drive period of another certain ultrasonic sensor 100.

[0031] <Specific operation example of the detection circuit> 4 is a diagram showing an equivalent circuit of the secondary side of the transformer Tr. The equivalent circuit shown in FIG. 4 includes an inductor component Lsec, a resistance component Rt, a capacitor component Ct, a capacitor component Cp, an inductor component Ls, a capacitor component Cs, and a resistance component Rs. The inductor component Lsec is an inductor component of the secondary winding of the transformer Tr. The resistance component Rt is a resistance R T The capacitance component Ct is the resistance component of the capacitor C T are capacitor components. The capacitor components Cp and Cs are capacitor components of the ultrasonic sensor element 2. The inductor component Ls is an inductor component of the ultrasonic sensor element 2. The resistance component Rs is a resistance component of the ultrasonic sensor element 2.

[0032] FIG. 5 is a diagram showing a schematic waveform of the output signal of envelope section 164 during the state detection period.

[0033] For example, the detection circuit 168 detects the state of the signal path based on the amplitude peak value of the terminal voltage (voltage between terminals T3 and T4) at the start of driving the ultrasonic sensor element 2 during the state detection period. Specifically, the detection circuit 168 measures the amplitude A1 of the envelope detection signal corresponding to the amplitude peak value of the terminal voltage (voltage between terminals T3 and T4) at the start of driving the ultrasonic sensor element 2. At the start of driving the ultrasonic sensor element 2 during the state detection period, no current flows through the ultrasonic sensor element 2 due to the inductor component Ls, so the amplitude A1 of the envelope detection signal increases the resistance R T The resistance component Rt (resistance R T The resistance value of the resistor is calculated.

[0034] For example, the detection circuit 168 measures the convergence time t1 until the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 becomes stable during the state detection period. In this case, the detection circuit 168 includes a counter for measuring the convergence time t1. The counter for measuring the convergence time t1 may be shared with the counter 166A. For example, the detection circuit 168 may determine that the terminal voltage of the ultrasonic sensor element 2 is stable during the state detection period when the change rate (differential value) of the terminal voltage of the ultrasonic sensor element 2 becomes smaller than the judgment value during the state detection period. Then, for example, the detection circuit 168 may determine that the transition to the reverberation time t2 has occurred when the change rate (differential value) of the terminal voltage of the ultrasonic sensor element 2 becomes larger than the judgment value after the terminal voltage of the ultrasonic sensor element 2 becomes stable. The convergence time t1 depends on the inductor component Ls of the ultrasonic sensor element 2 and the Q value of the ultrasonic sensor element 2.

[0035] For example, the detection circuit 168 measures the amplitude value of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 when it is stable during the state detection period. Specifically, the detection circuit 168 measures the amplitude value A2 of the envelope detection signal corresponding to the amplitude value of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 when it is stable during the state detection period. The amplitude value A2 may be measured at any timing when the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 is stable. For example, in the example shown in FIG. 5, the amplitude value A2 at a timing when a certain time has elapsed after the convergence time t1 ends is illustrated. The amplitude value A2 depends on the impedance of the ultrasonic sensor element 2 at the drive frequency.

[0036] For example, the detection circuit 168 measures the integral value of the envelope of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 during the state detection period. Specifically, the detection circuit 168 measures the integral value of the envelope detection signal corresponding to the integral value of the envelope of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 during the state detection period. The integral interval is, for example, the interval from the start of the state detection period to the start of the reverberation time t2.

[0037] For example, the detection circuit 168 measures the reverberation period of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 during the state detection period. Specifically, the detection circuit 168 measures the reverberation time t2 of the envelope detection signal corresponding to the reverberation period of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 during the state detection period.

[0038] For example, the detection circuit 168 measures the reverberation frequency (frequency in the reverberation period) of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 during the state detection period. Specifically, the detection circuit 168 measures the reverberation collection frequency (frequency at reverberation time t2) of the envelope detection signal corresponding to the reverberation frequency (frequency in the reverberation period) of the terminal voltage (voltage between terminals T3 and T4) of the ultrasonic sensor element 2 during the state detection period.

[0039] The detection circuit 168 includes a storage unit that stores expected values ​​(values ​​calculated from design values ​​of circuit constants) corresponding to the above-mentioned measured values, past measured values ​​(previous measured values, averages of the most recent measured values), etc. The storage unit is configured, for example, with a register.

[0040] The detection circuit 168 detects the state of the signal path based on the latest measured value and the value stored in the storage unit. For example, if the difference between the latest measured value and the value stored in the storage unit is smaller than a predetermined allowable value, the detection circuit 168 determines that no abnormality or characteristic fluctuation has occurred in the signal path. On the other hand, if the difference between the latest measured value and the value stored in the storage unit is larger than the predetermined allowable value, the detection circuit 168 determines that an abnormality or characteristic fluctuation has occurred in the signal path, and may notify an ECU (not shown) mounted on the vehicle 200 (see FIG. 1) via the control unit 160 and the interface 167 that an abnormality or characteristic fluctuation has occurred in the signal path of the ultrasonic sensor 100.

[0041] Fig. 6 is a diagram showing the impedance characteristics of the ultrasonic sensor element 2. Fig. 6 also shows schematic waveforms of the output signal of the envelope portion 164 during the state detection period at each of a plurality of impedance values ​​of the ultrasonic sensor element 2. At the series resonance point, current flows most easily through the ultrasonic sensor element 2, so that the amplitude value of the output signal of the envelope portion 164 in a stable state is the smallest. On the other hand, at the parallel resonance point, no current flows through the ultrasonic sensor element 2, so that the amplitude value of the output signal of the envelope portion 164 in a stable state is the largest.

[0042] Therefore, the current driver 12 may change the frequency of the second current based on the output signal of the DAC 11, and the detection circuit 168 may obtain the impedance characteristics of the ultrasonic sensor element 2 based on the waveform of the output signal of the envelope part 164 at each frequency of the second current. The detection circuit 168 may obtain the impedance characteristics of the ultrasonic sensor element 2 from the entire waveform of the output signal of the envelope part 164 at each frequency of the second current, for example, by waveform pattern matching, or may extract feature points of the waveform of the output signal of the envelope part 164 at each frequency of the second current and obtain the impedance characteristics of the ultrasonic sensor element 2 using the feature points.

[0043] The pattern for changing the frequency of the second current is not particularly limited, but for example, multiple state detection periods can be provided and the current driver 12 can change the frequency of the second current for each state detection period, thereby determining the impedance characteristics of the ultrasonic sensor element 2 in a short period of time.

[0044] <Other> The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The technical scope of the present disclosure is indicated by the claims, not by the description of the above-described embodiments, and should be understood to include all modifications that fall within the meaning and scope of the claims.

[0045] For example, in the above-described embodiment, detection circuit 168 is configured to obtain various measurement values ​​from the envelope detection signal, but may be configured to obtain various measurement values ​​from, for example, the output signal of LNA 13, the output signal of ADC 15, etc. For example, when detection circuit 168 is configured to obtain various measurement values ​​from the output signal of LNA 13, detection circuit 168 becomes an analog circuit, and, for example, a variable voltage source corresponding to the storage unit used in the above-described embodiment may be provided in the analog circuit. In this case, the value of the voltage output from the variable voltage source corresponds to the value stored in the storage unit.

[0046] <Additional Notes> Regarding the present disclosure, specific configuration examples of which have been shown in the above-mentioned embodiments, additional notes will be provided.

[0047] The driving device (1) of the present disclosure is a driving device configured to drive an ultrasonic sensor element (2) via a transformer (Tr), and includes a current driver (12) configured to supply a first current to the transformer during a driving period for driving the ultrasonic sensor element for distance measurement, and to supply a second current smaller than the first current to the transformer during a state detection period that does not overlap with the driving period, and a detection circuit (168) configured to detect a state of a signal path including the ultrasonic sensor element and the transformer based on a terminal voltage of the ultrasonic sensor element during the state detection period (first configuration).

[0048] According to the driving device of the first configuration, the state of the signal path can be detected.

[0049] The driving device of the first configuration may be configured (second configuration) such that the state detection period exists between when a distance measurement command is received and when the driving period starts.

[0050] In the driving device of the second configuration described above, there may be a plurality of the state detection periods, and the state detection period may exist other than the period from when the distance measurement command is received to when the driving period starts (third configuration).

[0051] In the driving device of any of the above first to third configurations, the detection circuit may be configured to detect the state of the signal path based on the amplitude peak value of the terminal voltage at the start of driving of the ultrasonic sensor element during the state detection period (fourth configuration).

[0052] In the driving device of any of the above first to fourth configurations, the detection circuit may be configured to detect the state of the signal path based on a convergence time until the terminal voltage stabilizes during the state detection period (fifth configuration).

[0053] In the driving device of any of the above first to fifth configurations, the detection circuit may be configured to detect the state of the signal path based on the amplitude value of the terminal voltage when it is stable during the state detection period (sixth configuration).

[0054] In the driving device of any of the above first to sixth configurations, the detection circuit may be configured to detect the state of the signal path based on an integral value of the envelope of the terminal voltage during the state detection period (seventh configuration).

[0055] In the driving device of any of the above first to seventh configurations, the detection circuit may be configured to detect the state of the signal path based on the reverberation period of the terminal voltage during the state detection period (eighth configuration).

[0056] In the driving device of any of the above first to eighth configurations, the detection circuit may be configured to detect the state of the signal path based on the reverberation frequency of the terminal voltage during the state detection period (ninth configuration).

[0057] In the drive device of any of the first to ninth configurations above, the current driver may be configured to change the frequency of the second current (tenth configuration).

[0058] In the driving device of any of the first to tenth configurations above, there may be a plurality of the state detection periods, and the current driver may be configured to change the frequency of the second current for each state detection period (an eleventh configuration).

[0059] An ultrasonic sensor (100) according to the present disclosure has a configuration (twelfth configuration) including the drive device of any one of the first to eleventh configurations, the ultrasonic sensor element, and the transformer.

[0060] A vehicle (200) of the present disclosure has a configuration (thirteenth configuration) including the ultrasonic sensor of the twelfth configuration. [Explanation of symbols]

[0061] 1. Signal Processing Device 2. Ultrasonic sensor element 11 DAC 12 Current Driver 13 LNA 14 PGA 15 ADC 16 Digital Processing Section 160 Control section 161 Transmission signal generator 162 BPF 163 ABS 164 Envelope Section 165 Reflected wave detector 166 TOF Measurement Unit 166A Counter 167 Interface 168 Detection Circuit 100 EMBODIMENT OF THE ULTRASOUND SYSTEM 200 vehicles 300 Object (obstacle) C1, C2, C T Capacitor Cp, Cs, Ct Capacitor components Ls, Lsec inductor components Rs, Rt resistance component R T resistance T1~T5 External terminals Tr Transformer

Claims

1. A driving device configured to drive an ultrasonic sensor element via a transformer, a current driver configured to supply a first current to the transformer during a drive period in which the ultrasonic sensor element is driven for distance measurement, and to supply a second current, the second current being smaller than the first current, to the transformer during a state detection period that does not overlap with the drive period; a detection circuit configured to detect a state of a signal path including the ultrasonic sensor element and the transformer based on a terminal voltage of the ultrasonic sensor element during the state detection period; A drive device comprising:

2. The drive device according to claim 1 , wherein the state detection period exists between when a distance measurement command is received and when the drive period starts.

3. There are a plurality of the state detection periods, The drive device according to claim 2 , wherein the state detection period exists other than a period from when the distance measurement command is received until when the drive period starts.

4. 2. The drive device according to claim 1, wherein the detection circuit is configured to detect the state of the signal path based on a peak value of the amplitude of the terminal voltage at the start of driving of the ultrasonic sensor element during the state detection period.

5. The drive device according to claim 1 , wherein the detection circuit is configured to detect the state of the signal path based on a convergence time required for the terminal voltage to become stable during the state detection period.

6. The drive device according to claim 1 , wherein the detection circuit is configured to detect the state of the signal path based on an amplitude value of the terminal voltage in a stable state during the state detection period.

7. The drive device according to claim 1 , wherein the detection circuit is configured to detect the state of the signal path based on an integral value of an envelope of the terminal voltage during the state detection period.

8. The drive device according to claim 1 , wherein the detection circuit is configured to detect the state of the signal path based on a reverberation period of the terminal voltage during the state detection period.

9. The driving device according to claim 1 , wherein the detection circuit is configured to detect the state of the signal path based on a reverberation frequency of the terminal voltage during the state detection period.

10. The drive arrangement of claim 1 , wherein the current driver is configured to vary a frequency of the second current.

11. There are a plurality of the state detection periods, The drive device according to claim 10 , wherein the current driver is configured to change a frequency of the second current for each state detection period.

12. A drive device according to any one of claims 1 to 11, The ultrasonic sensor element; The transformer; An ultrasonic sensor comprising:

13. A vehicle comprising the ultrasonic sensor of claim 12.

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