CN108519592A - Ultrasonic ranging excitation signal adjustment system and method for reducing blind spots - Google Patents

Abstract

The invention discloses a kind of supersonic sounding pumping signals reducing blind area to adjust system and method, the system comprises pumping signals to adjust module, to adjust the constituent for the pumping signal with specific composition structure for being sent to transmitting-receiving integrated ultrasonic transducer, wherein the signal sequence SS of the pumping signal with specific composition structure is to continue n in chronological order₁The positive periodic signal of a cycle T, the direct current signal that the duration is T/2 and lasting n₂The reversal periods signal of a cycle T.The disclosure accelerates the rate of decay of remained shock wave on transmitting-receiving integrated ultrasonic transducer by adjusting the constituent of the pumping signal with unique composed structure, to reduce the blind area in supersonic sounding.This scheme is easy to realize by software and hardware, and effect is good.

Description

Ultrasonic ranging excitation signal adjustment system and method for reducing blind spots

technical field

The invention belongs to the field of ultrasonic ranging, and in particular relates to an ultrasonic ranging excitation signal adjustment system and method for reducing blind spots.

Background technique

Ultrasound propagates along a straight line in an elastic medium, has good directionality, slow energy consumption, and can travel a long distance. Reflection and refraction will occur at the interface of the medium, and the propagation speed in the same medium is basically constant. Ultrasound is not sensitive to color and illumination, and can be used to identify transparent and poorly reflective objects (such as glass, polished objects); it is not sensitive to external light and electromagnetic fields, and can be used in harsh environments such as darkness, dust, smoke, and strong electromagnetic interference. ; In addition, the ultrasonic transducer has simple structure, small size, low cost, low technical difficulty, simple and reliable information processing, and is easy to miniaturize and integrate. The above-mentioned characteristics of ultrasound make it an important means of distance measurement. The non-contact measurement of distance can be realized by measuring the time (propagation time) it takes for ultrasonic waves to propagate a certain distance in the medium.

In order to improve the accuracy of ultrasonic ranging, it is necessary to accurately measure the propagation time of ultrasonic waves. The premise of accurately measuring the propagation time in the reflective ultrasonic ranging scheme is to correctly identify the ultrasonic echo signal. In the ultrasonic ranging system widely used at present, the ultrasonic transducer is an integrated transceiver, which is used to transmit ultrasonic waves and receive ultrasonic echo signals reflected back by the target. During distance measurement, the transceiver integrated ultrasonic transducer is excited by the excitation electric signal to emit ultrasonic waves for distance measurement. When the excitation electric signal stops, due to mechanical inertia factors, the ultrasonic transducer vibrator will still vibrate for several cycles, resulting in aftershock waves Signal. During the period affected by the aftershock wave, if the echo signal reflected by the obstacle also reaches the integrated ultrasonic transducer, the echo signal and the aftershock wave signal will be aliased so that the echo signal cannot be accurately distinguished. The echo signal can be correctly distinguished after the aftershock signal is attenuated to no effect. The distance that the ultrasonic wave propagates in the medium during the period when the aftershock wave decays to no effect is the blind area of measurement. The blind area of the existing transceiver integrated ultrasonic ranging system is about 30cm.

Contents of the invention

The purpose of one aspect of the present disclosure is to provide an ultrasonic ranging excitation signal adjustment system that reduces blind spots, including an excitation signal adjustment module, which is used to adjust the composition of the excitation signal containing a specific composition structure sent to the transceiver-integrated ultrasonic transducer components to speed up the attenuation speed of aftershock waves on the transceiver integrated ultrasonic transducer. The signal sequence SS of the excitation signal is a positive periodic signal lasting n ₁ periods T, a DC signal lasting T/2 and a reverse periodic signal lasting n ₂ periods T in time order.

In the above-mentioned ultrasonic ranging excitation signal adjustment system for reducing blind spots, the value range of _n1 is 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5 or 20; the value range of _n2 is 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 , 5.5, 6, 6.5, 7, 7.5 or 8.

Another object of the present disclosure is to provide a method for adjusting an excitation signal for ultrasonic ranging to reduce blind spots, which includes the following steps: Step 1: Setting the shortest duration threshold Ty of the excitation signal, the optimal number of reverse cycles N ₂ , the maximum The number of adjustments M, the number of forward cycles n ₁ and the number of reverse cycles n ₂ take a predetermined value; Step 2: Send an excitation signal to the transceiver integrated ultrasonic transducer, and the signal sequence SS of the excitation signal is n ₁ in chronological order A positive periodic signal with a period T, a DC signal with a duration of T/2, and a reverse periodic signal with a duration of n ₂ periods T; Step 3: Detect the excitation signal and the remaining vibration signal for a duration of t; if the time t is less than Ty, Go to step 4; otherwise go to step 7; step 4: judge whether the maximum number of adjustments is reached, if yes, go to step 5; otherwise go to step 6; step 5: update N ₂ , that is, set N ₂ = n ₂ , then go to Step 7; Step 6: update Ty and N ₂ , that is, Ty=t, N ₂ =n ₂ , then change the size of n ₂ in the signal sequence SS in a predetermined way and go to step 2 again; Step 7: take n ₁ Predetermined value, n ₂ =N2 The determined signal sequence SS is used as the selected ranging excitation signal to drive the transceiver integrated ultrasonic transducer to generate a formal ultrasonic measurement signal.

In the above-mentioned method for adjusting the excitation signal of the ultrasonic ranging to reduce the blind area, in the step 1, N ₂ =1.

In the above-mentioned method for adjusting the ultrasonic ranging excitation signal for reducing blind spots, in step 1, the predetermined value of _n1 is 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5 , 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, or 20.

In the above-mentioned method for adjusting the excitation signal of the ultrasonic ranging to reduce the blind area, in the step 1, the predetermined value of n ₂ is 1.

In the above-mentioned method for adjusting the ultrasonic ranging excitation signal for reducing blind spots, in step 6, the size of _n2 is 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8.

The disclosure speeds up the attenuation speed of aftershock waves on the transceiver integrated ultrasonic transducer by adjusting the components of the excitation signal with a unique composition structure, thereby reducing the blind area in ultrasonic distance measurement. This scheme is easy to realize through software and hardware, and the effect is good.

Description of drawings

Fig. 1 is a logic block diagram of an ultrasonic ranging system according to an embodiment of the present disclosure.

Fig. 2 is a flowchart of a method for adjusting an excitation signal according to an embodiment of the present disclosure.

FIG. 3 is a composition structure of an excitation signal sequence SS according to an embodiment of the present disclosure.

Fig. 4 is a flowchart of a method for adjusting an excitation signal according to another embodiment of the present disclosure.

FIG. 5 is a composition structure of an excitation signal sequence SS according to another embodiment of the present disclosure.

Detailed ways

The present disclosure will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the ultrasonic ranging system includes a transceiver integrated ultrasonic transducer and a main control module. The transceiver integrated ultrasonic transducer includes a transceiver integrated ultrasonic probe, an ultrasonic transmitting module, an ultrasonic receiving module and a signal amplification module. The control module includes a single-chip microcomputer system, an excitation signal adjustment module and a signal processing module. The single-chip system controls the excitation signal adjustment module to send the excitation signal sequence SS with a specific composition structure through the ultrasonic transmitting module, drives the transceiver integrated ultrasonic probe to transmit ultrasonic waves and receives the after-vibration signal through the ultrasonic receiving module to obtain the excitation signal and the duration of the after-vibration signal t. Different signal sequences SS correspond to different time t, and the excitation signal adjustment module adjusts the composition of SS, and finally obtains the signal sequence corresponding to the minimum duration t as the selected ranging excitation signal for formal ranging. The formal ranging process is as follows: use the selected ranging excitation signal to drive the transceiver integrated ultrasonic transducer to emit ultrasonic measurement signals, the measurement signals are reflected back by the target object, received by the ultrasonic receiving module, and the received signal passes through the signal amplification module After amplification, it is transmitted to the signal processing module for processing, and the signal processing module counts and calculates the distance value.

The excitation signal sequence is a positive periodic signal lasting n ₁ periods T, a DC signal lasting T/2 and a reverse periodic signal lasting n ₂ periods T in time order. The value of n ₁ is 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5 or 20. The value of n ₂ is 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8.

As shown in FIG. 2 , a flow chart of a method for adjusting an excitation signal for ultrasonic ranging to reduce blind spots includes steps 201 to 207 .

Step 201: set the minimum duration threshold of the excitation signal Ty=1 ms, the optimal number of reverse cycles N ₂ =1, the maximum number of adjustments M=14, the number of forward cycles n ₁ and the number of reverse cycles n ₂ take predetermined values, For example _n1 can be 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19 , 19.5 or 20, n ₂ can be 1.

Step 202: Control the IO port of the single-chip microcomputer through the main control module with the STM32 single-chip microcomputer as the core to output the excitation signal sequence SS with a specific composition structure, and start timing at the beginning of sending the excitation signal. As shown in Figure 3, the composition structure of the excitation signal sequence SS is a square wave signal (positive periodic signal) with a duration of n ₁ period T of 0.025ms (frequency 40kHz) and a DC signal with a duration of 0.0125ms in chronological order and a square wave signal (reverse periodic signal) with T of 0.025ms (frequency 40kHz) lasting n ₂ periods.

Step 203: When it is detected that the after-vibration signal on the transceiver-integrated ultrasonic transducer decreases below the predetermined threshold (at this time, the after-vibration disappears), the timing is ended, and the two timing times are subtracted to obtain the excitation signal and the after-vibration signal. time t. If the time t is less than Ty, go to step 204; otherwise, go to step 207.

Step 204: Judging whether the maximum number of adjustments has been reached, if yes, go to step 205, otherwise go to step 206.

Step 205: Update the value of N ₂ , ie N ₂ =n ₂ , and then go to step 207 .

Step 206: Update the values of Ty and N ₂ , that is, set Ty=t, N ₂ =n ₂ , and then change the size of n ₂ in the signal sequence SS in a predetermined way, and the value of n ₂ at this time is adjusted according to the number of times Adjust to 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8, and then perform step 202 again.

Step 207: Taking the signal sequence SS determined by n ₁ to be a predetermined value and n ₂ =N ₂ as the selected ranging excitation signal to drive the transceiver integrated ultrasonic transducer to generate a formal ultrasonic measurement signal.

As shown in FIG. 4 , a flow chart of a method for adjusting an excitation signal for ultrasonic ranging to reduce blind spots includes steps 401 to 407 .

Step 401: set the minimum duration threshold of the excitation signal Ty=1 ms, the optimal number of reverse cycles N ₂ =1, the maximum number of adjustments M=14, the number of forward cycles n ₁ and the number of reverse cycles n ₂ take predetermined values, For example _n1 can be 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19 , 19.5 or 20, n ₂ can be 1.

Step 402: Control the IO port of the single-chip microcomputer through the main control module with the STM32 single-chip microcomputer as the core to output the excitation signal sequence SS with a specific composition structure, and start timing at the beginning of sending the excitation signal. As shown in Figure 3, the composition structure of the excitation signal sequence SS is a sine wave signal (positive periodic signal) with a duration of n ₁ period T of 0.025ms (frequency is 40kHz), and a DC signal with a duration of 0.0125ms and a sine wave signal (reverse periodic signal) with T of 0.025ms (frequency 40kHz) lasting n ₂ periods.

Step 403: When it is detected that the after-vibration signal on the transceiver-integrated ultrasonic transducer has decreased below the predetermined threshold (at this time, the after-vibration is considered to have disappeared), the timing is ended, and the two timing times are subtracted to obtain the excitation signal and the after-vibration signal. time t. If the time t is less than Ty, go to step 404; otherwise go to step 407;

Step 404: Judging whether the maximum number of adjustments has been reached, if yes, go to step 405, otherwise go to step 406.

Step 405 : update the value of N ₂ , ie N ₂ =n ₂ , and then go to step 407 .

Step 406: Update the values of Ty and N ₂ , that is, set Ty=t, N ₂ =n ₂ , and then change the size of n ₂ in the signal sequence SS in a predetermined way, and the value of n ₂ at this time is adjusted according to the number of times Adjust to 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8, and then perform step 402 again.

Step 407: Taking the signal sequence SS determined by n ₁ to be a predetermined value and n ₂ =N ₂ as the selected ranging excitation signal to drive the transceiver-integrated ultrasonic transducer to generate a formal ultrasonic measurement signal.

The initial values of parameters such as the minimum duration threshold Ty, the optimal number of reverse cycles N ₂ , the maximum number of adjustments M, the number of forward cycles n ₁ and the number of reverse cycles n ₂ involved in this disclosure are not limited to the above-mentioned embodiments As disclosed in , other values can also be adopted, as long as they do not depart from the spirit and scope of the present invention.

Claims (7)

1. a kind of supersonic sounding pumping signal reducing blind area adjusts system, which is characterized in that module is adjusted including pumping signal, To adjust the constituent for the pumping signal containing specific composition structure for being sent to transmitting-receiving integrated ultrasonic transducer, encourage The signal sequence SS of signal is to continue n in chronological order₁The positive periodic signal of a cycle T, the direct current that the duration is T/2 are believed Number and continue n₂The reversal periods signal of a cycle T.

2. the pumping signal according to claim 1 for reducing blind area adjusts system, which is characterized in that the n₁Value model Enclose for 8,8.5,9,9.5,10,10.5,11,11.5,12,12.5,13,13.5,14,14.5,15,15.5,16,16.5,17, 17.5,18,18.5,19,19.5 or 20；The n₂Value range be 1,1.5,2,2.5,3,3.5,4,4.5,5,5.5,6, 6.5,7,7.5 or 8.

3. a kind of supersonic sounding pumping signal method of adjustment reducing blind area, which is characterized in that include the following steps：

Step 1：Set pumping signal minimum length in time threshold value Ty, optimal reversal periods number N₂, maximum adjustment number M, positive week Issue n₁With reversal periods number n₂Take predetermined value；

Step 2：Supersonic sounding pumping signal is sent to transmitting-receiving integrated ultrasonic transducer, the signal sequence SS of pumping signal is on time Between sequentially be continue n₁The positive periodic signal of a cycle T, the direct current signal that the duration is T/2 and lasting n₂A cycle T it is anti- To periodic signal；

Step 3：Pumping signal and its remained shock signal duration t are detected, if time t is less than Ty, goes to step 4；Otherwise it goes to step 7；

Step 4：Judge whether to reach maximum adjustment number, if so, going to step 5；Otherwise step 6 is gone to；

Step 5：Update N₂Even N₂=n₂, then go to step 7；

Step 6：Update Ty and N₂Even Ty=t, N₂=n₂, then change n in signal sequence SS in a predetermined manner₂Size Pass again to step 2；

Step 7：It will be by n₁Take predetermined value, n₂=N₂Identified signal sequence SS drives as selected ranging pumping signal and receives Hair integral type ultrasonic transducer generates formal ultrasonic measuring signal.

4. the supersonic sounding pumping signal method of adjustment according to claim 3 for reducing blind area, which is characterized in that the step In rapid 1, N₂=1.

5. the supersonic sounding pumping signal method of adjustment according to claim 3 for reducing blind area, which is characterized in that the step In rapid 1, n₁Predetermined value be 8,8.5,9,9.5,10,10.5,11,11.5,12,12.5,13,13.5,14,14.5,15, 15.5,16,16.5,17,17.5,18,18.5,19,19.5 or 20.

6. the supersonic sounding pumping signal method of adjustment according to claim 3 for reducing blind area, which is characterized in that the step In rapid 1, n₂Predetermined value be 1.

7. the supersonic sounding pumping signal method of adjustment according to claim 6 for reducing blind area, which is characterized in that the step In rapid 6, n₂Size according to the number being adjusted be followed successively by 1.5,2,2.5,3,3.5,4,4.5,5,5.5,6,6.5,7,7.5 or 8。