A three-probe array ultrasonic rangefinder

Abstract

A three-probe array ultrasonic rangefinder includes a triangular base, each base of the triangular base is provided with an ultrasonic probe, there is a height difference between the three ultrasonic probes, the three ultrasonic probes have different transmitting ultrasonic frequencies, the three ultrasonic probes are all connected to a control unit, the control unit includes: a monitoring module for monitoring the three ultrasonic probes to transmit and receive return sound waves simultaneously and in sequence, a ranging module for calculating the distance according to the transmission and reception timing of the three probes and according to the least square method, the monitoring module is connected to the start controlled end of the three ultrasonic probes, and the transmission and reception timing signal output ends of the three generating probes are connected to the monitoring module. The present invention provides a three-probe array ultrasonic rangefinder that is independent of a temperature compensation mechanism, has good operating reliability, and has high precision.

Description

Technical Field

[0001] The invention relates to an ultrasonic rangefinder. Background Art

[0002] Ultrasonic rangefinders or ultrasonic radars are widely used in unmanned driving, industrial control and other fields. Ultrasonic radar arrays play a key role in obstacle detection during motion due to their ability to perform “continuous detection”, but there is no way to implement multi-sensor fusion for distance measurement during relative stillness. In addition, most ultrasonic rangefinders that have certain requirements for accuracy have attached temperature measurement modules and apply them to distance calculations, which is the so-called temperature compensation mechanism. Summary of the invention

[0003] In order to overcome the shortcomings of the existing ultrasonic ranging method that relies on the temperature compensation mechanism, has poor operating reliability and low precision, the present invention provides a three-probe array ultrasonic ranging instrument that does not rely on the temperature compensation mechanism, has good operating reliability and high precision.

[0004] The technical solution adopted by the present invention to solve the technical problem is:

[0005] A three-probe array ultrasonic rangefinder comprises a triangular base, wherein an ultrasonic probe is arranged on each base of the triangular base, wherein the three ultrasonic probes have a height difference, and the three ultrasonic probes have different transmitting ultrasonic frequencies, and the three ultrasonic probes are all connected to a controllable unit, wherein the control unit comprises: a monitoring module for monitoring the three ultrasonic probes to transmit and receive return sound waves simultaneously and in sequence, and a ranging module for calculating the distance according to the transmission and reception timing of the three probes and the least square method, wherein the monitoring module is connected to the start controlled ends of the three ultrasonic probes, and the transmission and reception timing signal output ends of the three generating probes are connected to the monitoring module.

[0006] Furthermore, the triangular base is provided with pads with different heights, and different height differences are achieved by using different pads with different heights.

[0007] Furthermore, the height differences of the three ultrasonic probes are equal from low to high.

[0008] Preferably, the triangular base is in the form of an equilateral triangle. Of course, it can also be in the form of other triangles.

[0009] Furthermore, the three ultrasonic probes emit ultrasonic frequencies which are octaves different from each other.

[0010] The control unit is an industrial control board, which is located in the center of the triangular base and is connected to a power module.

[0011] The industrial control board outputs to a remote display screen through a communication interface, and the display screen is located on the back side of the triangular base.

[0012] The height difference of the three ultrasonic probes is 4 cm. In the distance measurement module, the distance between probe A and the target is s, and the ultrasonic sound speed is v. The sending and receiving time of the three probes A, B, and C is determined to be t. A ,t B ,t C .

[0013]

[0014]

[0015]

[0016] Written in matrix form

[0017]

[0018] Using the least squares method, we get

[0019]

[0020] The distance s is calculated.

[0021] The beneficial effects of the present invention are mainly manifested in that the array of three ultrasonic transceiver probes does not require a temperature compensation module, and the distance between the array and the target object is accurately calculated by data fusion of the three probes. In application, the array can be regarded as a separate ultrasonic radar and deployed in multi-array ultrasonic radar array occasions. The array device itself can achieve distance measurement with higher accuracy than that with an attached temperature compensation mechanism, and does not rely on a temperature module, making the system design simple, reliable in use, and high in accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the three-probe layout.

[0023] Figure 2 This is a schematic diagram of the height difference of the three probes on the triangular base.

[0024] Figure 3 It is a diagram of the computing architecture. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Reference Figure 1 to Figure 3A three-probe array ultrasonic rangefinder comprises a triangular base, on each base of the triangular base an ultrasonic probe is arranged, there is a height difference between the three ultrasonic probes, the three ultrasonic probes have different transmitting ultrasonic frequencies, the three ultrasonic probes are all connected to a control unit, the control unit comprises: a monitoring module for monitoring the three ultrasonic probes to transmit and receive return sound waves simultaneously and in sequence, a ranging module for calculating the distance according to the transmission and reception timing of the three probes and according to the least squares method, the monitoring module is connected to the start-controlled ends of the three ultrasonic probes, and the transmission and reception timing signal output ends of the three generating probes are connected to the monitoring module.

[0027] Furthermore, the triangular base is provided with pads with different heights, and different height differences are achieved by using different pads with different heights.

[0028] Furthermore, the height difference of the three ultrasound probes is equal to the height difference from the lowest to the highest, for example, 4 cm.

[0029] Preferably, the triangular base is in the form of an equilateral triangle. Of course, it can also be in the form of other triangles.

[0030] Furthermore, the three ultrasound probes emit ultrasound with frequencies that are octaves different from each other.

[0031] The control unit is an industrial control board, which is located in the center of the triangular base and is connected to a power module.

[0032] The industrial control board outputs to a remote display screen through a communication interface, and the display screen is located on the back side of the triangular base.

[0033] The height difference of the three ultrasonic probes is 4 cm. In the distance measurement module, the distance between probe A and the target is s, and the ultrasonic sound speed is v. The sending and receiving time of the three probes A, B, and C is determined to be t. A ,t B ,t C .

[0034]

[0035]

[0036]

[0037] Written in matrix form

[0038]

[0039] Using the least squares method, we get

[0040]

[0041] The distance s is calculated.

[0042] In this embodiment, Figure 1 As shown, the three probes can be raised by pads of different heights so that the height difference is 4 cm. The side length of the triangular seat is between 20 cm and 30 cm, which is set according to the probe aperture length. The probe aperture is related to the ultrasonic frequency specifications of each probe. Probe A emits 24K Hz ultrasound, probe B emits 48K Hz, and probe C emits 96K Hz ultrasound. According to the numerical calculation formula of the ultrasonic near-field distance N:

[0043]

[0044] It can be seen that in order to keep the near-field values ​​of the three unchanged, when the frequency f ratio of A:B:C is 1:2:4, the aperture d ratio of A:B:C is 1:(1 / 1.414):(1 / 2).

[0045] Assume that the distance between probe A and the target object is s, and the ultrasonic sound speed is v. Since this solution does not rely on the temperature compensation mechanism, the sound speed v is an unknown quantity. After the system is powered on, the control unit monitors the three probes to transmit simultaneously, and receives the returned sound waves in sequence. Since the frequencies of the sound waves emitted by the three probes differ by an octave, even when the Doppler effect is introduced during movement, based on a slight frequency shift of the returned waveform, it can be determined that probe A has retracted the sound waves emitted by probe A, probe B has retracted the sound waves emitted by B, and probe C has retracted the sound waves emitted by C. The transmission and reception are timed and the time is determined to be t A ,t B ,t C , calculate the distance s according to the least squares method.

[0046] The working process of this embodiment is:

[0047] Step 1: The control unit starts each probe to transmit ultrasound of its own frequency;

[0048] Step 2: Wait until all probes receive echoes and return the timing value;

[0049] Step 3, calculate the distance s using the least squares method introduced above;

[0050] Step 4. Return to step 1.

[0051] In step 2, the echo is received and the frequency is determined. Only the frequency emitted by the current probe (a certain degree of deviation is allowed) can be considered as the echo that needs to be timed out.

[0052] The solution of this embodiment is applied when the array device and the distance measuring object are relatively stationary. When there is relative motion between the array device and the distance measuring object, it is still applicable as long as the frequency offset amplitude caused by the Doppler effect caused by the motion speed is within 50%.

Claims

1. A three-probe array ultrasonic rangefinder, It is characterized in that It comprises a triangular base, on each base of the triangular base an ultrasonic probe is arranged, there is a height difference between the three ultrasonic probes, the three ultrasonic probes have different transmitting ultrasonic frequencies, the three ultrasonic probes are all connected to a control unit, the control unit comprises: a monitoring module for monitoring the three ultrasonic probes to transmit and receive the return sound waves in sequence, a ranging module for calculating the distance according to the transmission and reception timing of the three probes and the least square method, the monitoring module is connected to the start controlled end of the three ultrasonic probes, and the transmission and reception timing signal output ends of the three ultrasonic probes are connected to the monitoring module; the height difference between the three ultrasonic probes is 4cm, in the ranging module, the interval distance between probe A and the target object is s, the ultrasonic sound speed is v, and the transmission and reception time of the three probes A, B, and C is determined to be t A ,t B ,t C ; Written in matrix form Using the least squares method, we get The distance s is calculated.

2. A three-probe array ultrasonic rangefinder as claimed in claim 1, It is characterized in that The triangular base is provided with pads with different heights.

3. A three-probe array ultrasonic rangefinder as claimed in claim 2, It is characterized in that The height differences of the three ultrasonic probes are equal from low to high.

4. A three-probe array ultrasonic rangefinder as claimed in any one of claims 1 to 3, It is characterized in that The triangular base is an equilateral triangle.

5. A three-probe array ultrasonic rangefinder as claimed in any one of claims 1 to 3, It is characterized in that The three ultrasonic probes emit ultrasonic frequencies with different octaves.

6. A three-probe array ultrasonic rangefinder as claimed in any one of claims 1 to 3, It is characterized in that The control unit is an industrial control board, which is located in the center of the triangular base and is connected to a power module.

7. A three-probe array ultrasonic rangefinder as claimed in claim 6, It is characterized in that The industrial control board outputs to a remote display screen through a communication interface, and the display screen is located on the back side of the triangular base.

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