CN113866775A

CN113866775A - Ultrasonic sensor and detection method

Info

Publication number: CN113866775A
Application number: CN202111144314.5A
Authority: CN
Inventors: 陈武强
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-09-28
Filing date: 2021-09-28
Publication date: 2021-12-31

Abstract

The invention discloses an ultrasonic sensor and a detection method, wherein in the detection period of a single modulation signal, the sensor sequentially generates n different modulation signals at uniform and close time intervals, and the n different modulation signals drive a microphone to work in turn to generate ultrasonic waves at different time intervals and/or different working frequencies; transmitting ultrasonic waves and receiving reflected waves of an object at the same time interval and the same working frequency, and generating echo signals after pairing; in the detection period of a single modulation signal, the sensor transmits n times of ultrasonic waves and receives n times of reflected waves at uniform and close time intervals to finish n times of detection so as to improve the detection response speed of the ultrasonic sensor. The invention improves the detection reaction speed of the ultrasonic sensor without increasing the number of the microphones, has low cost and high performance, and is conveniently applied to various vehicles and electronic and electrical equipment facilities such as automobiles, unmanned aerial vehicles, unmanned vehicles, robots, household appliances, security protection and the like.

Description

Ultrasonic sensor and detection method

Technical Field

The invention relates to the field of ultrasonic detection, in particular to an ultrasonic sensor and a detection method.

Background

The ultrasonic sensor is widely applied to various vehicles such as automobiles, unmanned planes, unmanned vehicles and robots and electronic and electrical equipment facilities.

At present, a conventional ultrasonic sensor is usually a single-microphone sensor and a single-cycle single-modulation signal detection method, fig. 1 is a schematic structural diagram of the single-microphone sensor, and fig. 2 is a schematic timing diagram of the single-cycle single-modulation signal detection of the conventional single-microphone sensor, it can be seen that the microphone transmits only modulation signals S1-10a1 in a single detection cycle Tf, and usually only one echo signal E1-10a1 is used for detecting an object at a certain distance.

In air, because the ultrasonic wave is limited by the propagation speed (the sound velocity v is usually 340 m/s), if the detection range Lf of the sensor is large, the detection period Tf is large (Tf is 2 × Lf/v), and it is difficult to meet the requirement of fast response (refresh) in many applications.

In order to increase the detection response speed of the ultrasonic sensor, the present inventors proposed a solution in the applied invention CN 105549022A: the single sensor integrates a plurality of microphones (also called transducers) with different frequency specifications, works according to a certain time sequence, and forms n times of emission and reception in a single microphone detection period Tf so as to improve the detection response speed of the sensor, but the sensor has to be provided with two or more microphones according to the CN105549022A scheme. When the sensor is provided with two microphones, the detection reaction speed is increased to two times of the reaction speed of the traditional single-microphone sensor, when the sensor is provided with three microphones, the detection reaction speed is increased to three times of the reaction speed of the traditional single-microphone sensor, and when the sensor is provided with n microphones, the detection reaction speed is increased to n times of the reaction speed of the traditional single-microphone sensor; however, the scheme increases the number of microphones and the cost, and simultaneously, the detection response speed is improved by a limited multiple, and the comprehensive performance is not improved.

Disclosure of Invention

In view of the problems in the prior art, an object of the present invention is to provide an improved ultrasonic sensor and a detection method using the same.

In order to achieve the purpose, the ultrasonic sensor comprises a receiving and transmitting integrated microphone, wherein in a detection period of a single modulation signal, the sensor sequentially generates n different modulation signals at uniform and close time intervals, n is more than or equal to 2, and the n different modulation signals drive the microphone to work in turn to generate ultrasonic waves at different time intervals and/or different working frequencies;

transmitting ultrasonic waves and receiving reflected waves of an object at the same time interval and the same working frequency, and generating echo signals after pairing;

in the detection period of a single modulation signal, the sensor transmits n times of ultrasonic waves and receives n times of reflected waves at uniform and close time intervals to finish n times of detection so as to improve the detection response speed of the ultrasonic sensor.

Furthermore, the ultrasonic waves are transmitted at different time intervals and different working frequencies, so that the ultrasonic waves generate reflected waves at different time intervals and different working frequencies, the transmitted ultrasonic waves and the reflected waves have the same time interval parameters and the same working frequencies, and the echo signals are determined to be effective after pairing.

Further, the sensor detects a measuring range Lf, and the n different modulation signals include: modulation signal 1, modulation signal 2, … … modulation signal n, the cycle of detecting of single modulation signal is Tf, and in detecting cycle Tf, each modulation signal launches in proper order:

the time interval between the beginning of transmitting the modulation signal 2 and the beginning of transmitting the modulation signal 1 is Tj 1; the time interval between the beginning of transmitting the modulation signal 3 and the beginning of transmitting the modulation signal 2 is Tj 2; the modulation signals are analogized in the same way; the time interval from the beginning of the transmission of the modulation signal 1 of the next period to the transmission of the modulation signal n of the present period is Tjn.

Further, Tj1+ Tj2+ … … + Tjn ≈ Tf, Tj1 ≈ Tj2 ≈ … … ≈ Tjn ≈ Tf/n; n times of emission signals and echo signals are formed in a single modulation signal detection period Tf, so that the detection response speed of the ultrasonic sensor is increased to n times of that of a single modulation signal detection mode.

Further, when the sensor determines that the echo signal is close to or overlaps with a modulation signal to be transmitted, the sensor adjusts the time interval Tj1, the time interval Tj2, and the time interval Tjn of … … to avoid or reduce mutual interference between the transmitted modulation signal and the received echo signal.

Further, after adjustment, when the sensor judges that the echo signal of the object is separated from the modulation signal, the sensor restores the transmission starting time interval of each modulation signal to the original transmission starting time interval so as to restore the uniformity of the transmission starting time interval of each modulation signal and the receiving time interval of each echo signal.

Furthermore, the sensor adjusts the number n of the modulation signals according to the size of the detection range Lf, when the detection range Lf is larger, n is set to be larger, and when the detection range Lf is smaller, n is set to be smaller.

Further, the modulation signal 1, the modulation signal 2, and the modulation signal … … generated by the sensor may be a fixed frequency signal, or a chirp signal, or an FSK signal, or an MSK signal, and the corresponding echo signals are distinguished by different signal types.

Furthermore, the type, the transmitting sequence and the starting transmitting time interval of the modulation signals of the plurality of sensors are all dynamically adjusted.

A detection method of ultrasonic sensor; the method comprises the following steps:

1) the sensor detects a measuring range Lf, and the n different modulation signals comprise: modulating signals 1, 2 and … … to modulate signals n, wherein detection periods of single modulation signals are all Tf, Tf is 2 × Lf/v, and v is sound velocity;

2) the time interval between the beginning of transmitting the modulation signal 2 and the beginning of transmitting the modulation signal 1 is Tj 1;

the time interval between the beginning of transmitting the modulation signal 3 and the beginning of transmitting the modulation signal 2 is Tj 2; the modulation signals are analogized in the same way; the time interval between the beginning of transmitting the next period modulation signal 1 and the beginning of transmitting the current period modulation signal n is Tjn;

3) setting system parameters: tj1+ Tj2+ … … + Tjn Tf, Tj1 Tj2 … … Tjn Tf/n, and different modulation signals are set to different working frequencies;

4) each modulation signal is transmitted in sequence, and n times of transmission signals and echo signals are formed in a single modulation signal detection period Tf;

5) after pairing, determining the transmitting signals and the echo signals with the same time interval parameters and the same working frequency as effective signals;

6) the n effective signals enable the detection period of the sensor to be reduced to Tf/n, so that the detection response speed of the ultrasonic sensor is increased to n times of that of a single modulation signal detection mode.

The ultrasonic sensor and the detection method adopt the single-microphone sensor, greatly improve the detection reaction speed of the ultrasonic sensor without increasing the number of microphones, have low cost and high performance, and are convenient to be widely applied to various vehicles and electronic and electrical equipment facilities such as automobiles, unmanned aerial vehicles, unmanned vehicles, robots, household appliances, security protection and the like.

Drawings

FIG. 1: the single microphone sensor structure schematic diagram;

FIG. 2: a single-period and single-modulation signal detection timing diagram of a traditional single microphone sensor;

FIG. 3: the invention discloses a single-period double-modulation signal detection timing sequence diagram of a single microphone sensor;

FIG. 4: the invention discloses a timing diagram for interference-free detection of a sensor monocycle double-modulation signal.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

As shown in fig. 1, 2, 3, and 4, in the ultrasonic sensor of the present invention, the sensor 10 includes a transceiver integrated microphone 10a1, as shown in fig. 1, when the sensor detects an object, in a detection period Tf of a single modulation signal, the sensor 10 sequentially generates n (n is greater than or equal to 2) different modulation signals at uniform and close time intervals, the n different modulation signals drive the microphone 10a1 to work in turn, and the microphone 10a1 externally emits ultrasonic waves, receives a reflected wave of the object, and generates an echo signal; in the detection period Tf of a single modulation signal, the sensor 10 completes n detections at uniform and close time intervals, so as to increase the detection response speed of the ultrasonic sensor 10.

The ultrasonic sensor of the invention is implemented by a detection method; the method comprises the following steps:

In the present invention, the sensor is provided with 2 modulated emission signals, i.e. n is 2, as shown in fig. 3, a schematic diagram of a single-period and double-modulated signal detection timing sequence of the single-microphone sensor of the present invention is shown. In a single modulation signal detection period Tf, the sensor 10 generates modulation signals S1-10a1 and S2-10a1 at uniform and close time intervals, the modulation signal S1-10a1 starts to emit after-interval Tj1, the modulation signal S2-10a1 starts to emit, the modulation signal S2-10a1 starts to emit after-interval Tj2, the next-period modulation signal S1-10a1 starts to emit, Tj1+ Tj2 is Tf, and Tj1 is substantially equal to Tj2 and is substantially equal to Tf/2. After the modulation signal is transmitted, the transmitting-receiving integrated microphone 10a1 emits ultrasonic waves, the ultrasonic waves are reflected by an object, the microphone 10a1 receives the reflected waves, echo signals generated by modulation signals S1-10a1 on the object at a distance L1 (L1-T1 v/2) are E1-10a1, and echo signals generated by modulation signals S2-10a1 on the object at the same position are E2-10a 1.

Assuming the object is stationary or has a small relative velocity with respect to the sensor, the detection time of the two modulation signals for the object at the same location is equal, which is T1. It can be seen that the time interval between the microphone 10a1 receiving the echo signal E2-10a1 and the echo signal E1-10a1 is Tj1, the time interval between the microphone receiving the next cycle echo signal E1-10a1 and the current cycle echo signal E2-10a1 is Tj2, Tj1+ Tj2 ≈ Tf, and Tj1 ≈ Tj2 ≈ Tf/2. When the relative velocity between the object and the sensor is relatively high, a certain deviation exists between the time interval of receiving the echo signal and the transmission time interval of the transmission signal in the single detection period Tf, and therefore a certain deviation allowable range is usually set for the two. Such processing methods are not inconsistent with the claims that are appended to this invention.

The single-period double-modulation signal sensor forms 2 times of emission signals and echo signals in a single modulation signal detection period Tf, and the detection period of the sensor is reduced to Tf/2, so that the detection response speed of the sensor is 2 times of that of the traditional single-period single-modulation signal sensor.

In analogy, in a single modulation signal detection period Tf, the sensor 10 sequentially generates n (n > 2) different modulation signals at uniform and close time intervals, and the n different modulation signals drive the microphone 10a1 to work in turn, so that the detection response speed of the sensor 10 can be increased to n times (n > 2) of the response speed in a single modulation signal detection mode. According to the invention, under the condition that the number of the microphones is not increased, the detection reaction speed of the sensor is greatly improved by increasing different modulation signals in a single detection period and working in sequence.

The ultrasonic sensor and the detection method thereof have the advantages that the starting transmission time intervals of modulation signals are Tj1, Tj2, … … and Tjn, Tj1+ Tj2+ … … + Tjn is Tf, Tj1 is approximately equal to Tj2 and approximately equal to Tjn … … and approximately equal to Tjn/n, when Tj1 is equal to Tj2 and approximately equal to Tjn … … and is equal to Tjn/n, the starting transmission time intervals of the transmission signals of the sensor are most uniform, and the receiving time intervals of echo signals are also most uniform.

When the sensor detects that the echo signal of the object coincides with the modulation signal transmitted by the sensor, the echo signal and the modulation signal generate mutual interference, which can cause the problems of reduction of the identification rate of the echo signal, deformation of the waveform of the modulation signal, and the like. In order to solve the problem of signal interference, the present invention adopts 4 available schemes to improve the signal interference resistance.

1. In the detection period of a single modulation signal, the sensor sequentially generates n different modulation signals at different time intervals, namely the time intervals are used as a limiting parameter, and the transmitting signals and the echo signals with the same time interval parameter are paired and confirmed to be effective signals.

2. In the detection period of a single modulation signal, the sensor sequentially generates n different modulation signals at different working frequencies, namely the working frequency is used as a limited parameter, and when a transmitting signal and an echo signal with the same working frequency are paired, the transmitting signal and the echo signal are confirmed to be effective signals. In this embodiment, the operating frequency of the microphone may be a resonant frequency of the microphone, or may be a fixed operating frequency with a deviation from the resonant frequency, or may be an unfixed operating frequency with a signal encoding function and a change around the resonant frequency, for example, when the operating mode is a Chirp (Chirp) signal, an FSK signal, an MSK signal, or other modulation signal mode.

3. When the sensor judges that the echo signal of the object is close to or overlapped with the modulation signal, the sensor adjusts the time interval Tj1 for starting transmission of the modulation signal 2 and the modulation signal 1, the time interval Tj2 for starting transmission of the modulation signal 3 and the modulation signal 2, … …, the time interval Tjn for starting transmission of the modulation signal 1 in the next period and the modulation signal n in the current period so as to avoid or reduce mutual interference between the transmitted modulation signal and the received echo signal.

The present invention is exemplified by a sensor having 2 modulated emission signals, and fig. 4 is a timing diagram of interference-free detection of a sensor with a single-period and double-modulated signal according to the present invention. As can be seen from the figure, when the echo signal E1-10a1 of the sensor 10 is close to and coincident with the original modulation signal S2-10a1, i.e. the distance L2(L2 ═ T2 ×/2) of the measured object is close to or at the distance Lj1(Lj1 ═ Tj1 ×/2), the sensor adjusts the start transmission time interval Tj1 of the modulation signals S2-10a1 and S1-10a1 to Tj1a, so as to avoid interference between the modulation signals S2-10a1 and the echo signals E1-10a1 of the modulation signals S1-10a1, and accordingly, the starting transmission time interval Tj2 between the next period modulation signal S1-10a1 and the present period modulation signal S2-10a is adjusted to be Tj2a (Tj1a + Tj2a ═ Tf), so as to avoid the interference between the next period modulation signal S1-10a1 and the echo signal E2-10a1 of the present period modulation signal S2-10a 1. When the sensor judges that the echo signal of the object is separated from the original modulation signal, the sensor restores the time interval from the starting transmission of each modulation signal to the original time interval from the starting transmission of each modulation signal so as to restore the uniformity of the time interval from the starting transmission of each modulation signal and the time interval from the receiving of each echo signal.

4. The modulation signal 1, the modulation signal 2, and the modulation signal … … generated by the sensor of the present invention may be a fixed frequency signal, or a Chirp (Chirp) signal, or an FSK signal, or an MSK signal, or other types of modulation signals. During detection, the sensor judges the object detection result of each modulation signal according to the consistency of the echo signal and the type of the transmitted signal, different modulation signals adopt different signal types so as to be convenient for identification, confusion is avoided, and corresponding echo signals are distinguished through different signal types.

According to the ultrasonic sensor, the number n of the modulation signals transmitted in a single period is adjusted by the sensor according to the size of the detection range Lf, when the detection range Lf is larger, n is set to be larger, and when the detection range Lf is smaller, n is set to be smaller. For example, when the detection range of the sensor is 8 to 10 meters, n is set to 4 or 5, when the detection range is 6 to 8 meters, n is set to 3 or 4, when the detection range is 4 to 6 meters, n is set to 2 or 3, and when the detection range is 2 to 4 meters, n is set to 2. The ultrasonic sensor and the detection method ensure that the sensor has higher detection response speed under different measuring ranges by flexibly setting the number of the modulation signals.

According to the ultrasonic sensor and the detection method, in the working process, the type, the transmitting sequence and the starting transmitting time interval of the modulation signal of the sensor are dynamically adjusted. The type, the transmitting sequence and the starting transmitting time interval of the modulation signals of the sensors are regularly or randomly adjusted, and the method has a further filtering function on the same frequency interference and other external interference of other sensors, so that the anti-interference capability of the system is further improved, the misdetection and the misinformation of the system are reduced, and the working reliability and the accuracy of the system are improved.

The ultrasonic sensor and the detection method greatly improve the detection reaction speed of the ultrasonic sensor while not increasing the number of the microphones; meanwhile, the device has the advantages of low cost and high performance, and is convenient to be widely applied to various vehicles such as automobiles, unmanned aerial vehicles, unmanned vehicles, robots, household appliances and security and electronic equipment facilities.

The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, which is defined by the appended claims and their equivalents.

Claims

1. An ultrasonic sensor is characterized by comprising a transceiving integrated microphone, wherein in a detection period of a single modulation signal, the sensor sequentially generates n different modulation signals at uniform and close time intervals, n is more than or equal to 2, and the n different modulation signals drive the microphone to work in turn to generate ultrasonic waves at different time intervals and/or different working frequencies;

2. The ultrasonic transducer according to claim 1, wherein the echo signal is confirmed to be valid by setting the transmitted ultrasonic waves at different time intervals and different operating frequencies so that the transmitted ultrasonic waves and the reflected waves at different time intervals and different operating frequencies are generated, and pairing the transmitted ultrasonic waves and the reflected waves at the same time interval parameter and the same operating frequency.

3. The ultrasonic transducer of claim 1, wherein the transducer detects a range Lf, and the n different modulated signals comprise: modulation signal 1, modulation signal 2, … … modulation signal n, the cycle of detecting of single modulation signal is Tf, and in detecting cycle Tf, each modulation signal launches in proper order:

4. The ultrasonic sensor of claim 3, wherein Tj1+ Tj2+ … … + Tjn ≈ Tf, Tj1 ≈ Tj2 ≈ … … ≈ Tjn ≈ Tf/n; n times of emission signals and echo signals are formed in a single modulation signal detection period Tf, so that the detection response speed of the ultrasonic sensor is increased to n times of that of a single modulation signal detection mode.

5. The ultrasonic transducer of claim 3, wherein the transducer adjusts the time interval Tj1, the time interval Tj2, the time interval Tjn of … … to avoid or reduce interference between the transmitted modulated signal and the received echo signal when the transducer determines that the echo signal is close to or overlaps an upcoming transmitted modulated signal.

6. The ultrasonic transducer of claim 5, wherein after the adjustment, when the transducer determines that the echo signal of the object is separated from the modulated signal, the transducer restores the transmission start time interval of each modulated signal to the predetermined transmission start time interval to restore the uniformity of the transmission start time interval of each modulated signal and the reception time interval of each echo signal.

7. The ultrasonic sensor according to claim 3, wherein the sensor adjusts the number n of the modulation signals according to the magnitude of the detection range Lf, wherein n is set to be larger when the detection range Lf is larger, and n is set to be smaller when the detection range Lf is smaller.

8. An ultrasonic transducer according to claim 3, wherein the modulated signal 1, the modulated signal 2, the modulated signal … …, the modulated signal n, can be a fixed frequency signal or a chirp signal or an FSK signal or an MSK signal, and the respective echo signals are distinguished by different signal types.

9. The ultrasonic transducer of claim 1, wherein the type, the transmission sequence, and the transmission start time interval of the modulation signals of a plurality of said transducers are dynamically adjusted.

10. A detection method of ultrasonic sensor; the detection method is characterized by comprising the following steps:

2) the time interval between the beginning of transmitting the modulation signal 2 and the beginning of transmitting the modulation signal 1 is Tj 1; the time interval between the beginning of transmitting the modulation signal 3 and the beginning of transmitting the modulation signal 2 is Tj 2; the modulation signals are analogized in the same way; the time interval between the beginning of transmitting the next period modulation signal 1 and the beginning of transmitting the current period modulation signal n is Tjn;