Detection method for optimizing residual vibration frequency and detection circuit adopting method

Abstract

The invention provides a detection circuit of a detection method for optimizing residual vibration frequency, the detection circuit comprises a driving circuit, an ultrasonic probe to be detected, a signal processing device and two resistors connected in parallel, one resistor is connected with a microcontroller to control a switch connected with the detection circuit; the detection method comprises the following steps: step 1, carrying out residual vibration frequency detection to obtain a detection result; step 2, judging a detection result, and step 3, carrying out residual vibration frequency detection again to obtain a secondary detection result; and 4, comparing the result with a standard value. According to the detection method for optimizing the residual vibration frequency provided by the invention, the resistance on the detection circuit is increased, so that the impedance at the periphery of the sensor is increased, the residual vibration is increased, the residual vibration which cannot be detected originally is expanded to a detection range, detection is realized, part of sensors with weak vibration of a probe are detected again, and the detection efficiency is improved. And the production yield is improved, and the economic benefits of enterprises are increased.

Description

Technical Field

[0001] The invention relates to a detection method for optimizing residual vibration frequency. Background Art

[0002] With the rapid development of science and technology, more and more intelligent devices are installed in cars, making cars more intelligent. However, the terminals of these intelligent devices ultimately need to use sensors to realize them. Ultrasonic sensors are widely used as products with mature and stable technology and high cost performance.

[0003] Therefore, in the production process of ultrasonic sensors, high-efficiency and high-quality control processes are required to maximize the economic benefits of the factory. During the production process, the sensor needs to be tested for residual vibration frequency. Once the residual vibration frequency is found to be excessive, it can only be passively accepted and the product will be scrapped. However, a considerable number of these defective products have no problems with the product itself, and its main function of detecting obstacles is still intact. It is only because of some reasons that the residual vibration is insufficient, resulting in abnormal residual vibration frequency detection results, which in turn causes the sensor to be scrapped, causing unnecessary waste.

[0004] In order to improve the yield rate, manufacturers use the following two methods: One method is to use peripheral circuits, such as changing the capacitance or inductance value in the matching circuit, to put the entire circuit in a frequency mismatch state to extend the residual vibration time, thereby improving the residual vibration frequency detection NG caused by insufficient residual vibration time. However, this method will cause the residual vibration time of all sensors to be too long, thereby increasing the detection blind area of ​​all sensors.

[0005] One method is to improve the residual vibration frequency detection NG caused by insufficient residual vibration time by changing the internal design of the ultrasonic sensor sub-component-probe, such as changing the hardness or ratio of the internal glue to extend the residual vibration time. However, this method will cause the residual vibration time of all sensors to be too long, thereby increasing the detection blind area of ​​all sensors. In addition, the design verification introduction cycle of this change is also very long.

[0006] Therefore, it is necessary to improve the manufacturer's detection method to adapt it to the current residual vibration detection without affecting the structure and use of the sensor itself. Summary of the invention

[0007] The technical problem to be solved by the present invention is: to provide a detection method for optimizing the residual vibration frequency, to achieve the extension of the residual vibration frequency through circuit and software control, so that the residual vibration frequency detection module inside the ASIC can obtain a sufficient number of waveforms, thereby avoiding or reducing the failure of residual vibration frequency detection caused by insufficient number of waveforms; the sound pressure of the sensor using an ultrasonic probe with a low Q value (weaker vibration) can be increased, the requirement for receiving gain can be reduced, and the signal-to-noise ratio can be improved.

[0008] In order to solve the above technical problems, the technical solution of the present invention is: A detection circuit for optimizing a detection method for residual vibration frequency includes a driving circuit, the driving circuit is connected to an ultrasonic probe to be detected, the ultrasonic probe is externally connected to a signal processing device, two parallel resistors are arranged between the ultrasonic probe and the signal processing device, one of the resistors is connected to a microcontroller to control a switch connected to the detection circuit; the detection method is as follows: The first step is to detect the residual vibration frequency and obtain the test results; The second step is to judge the test result, whether the frequency deviation rate is less than the standard value, and if it is less than the standard value, the test is judged to be qualified and the test is completed; when the frequency deviation rate is greater than the standard value, the switch is disconnected by the microcontroller, and one of the two parallel resistors is disconnected, so that the resistance in the detection circuit increases; The third step is to perform the residual vibration frequency test again to obtain the secondary test result; The fourth step is to compare the result with the standard value to see if the frequency deviation rate is less than the standard value. If it is less than the standard value, the test is considered qualified and the test is completed; when the frequency deviation rate is greater than the standard value, the test is considered unqualified and the product is scrapped.

[0009] Furthermore, in the detection circuit, the two parallel resistors may be resistors with the same resistance value or resistors with different resistance values.

[0010] Furthermore, the resistor connected to the microcontroller is replaced by a transistor.

[0011] Furthermore, the transistor is connected to an EEPROM (Electrically Erasable Programmable Read-Only Memory).

[0012] Furthermore, the signal processing device and the microcontroller are both integrated inside the detection chip.

[0013] Furthermore, the EEPROM and transistor are integrated inside the detection chip.

[0014] Furthermore, the standard values ​​used for detection are standard values ​​for residual vibration detection of ultrasonic waves of various specifications, which are used by manufacturers to determine whether ultrasonic sensors are qualified.

[0015] Compared with the prior art, the present invention provides a detection method for optimizing the residual vibration frequency. By increasing the resistance on the detection circuit, the impedance of the sensor periphery is increased, thereby increasing the residual vibration, and expanding the residual vibration that was originally undetectable to the detection range to achieve detection, thereby re-detecting some sensors that have weak probe vibration, improving the production yield and increasing the economic benefits of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 A schematic flow chart of the method of the present invention is shown.

[0017] Attached Figure 2 The detection circuit diagram in the first embodiment of the present invention is shown.

[0018] Attached Figure 3 The detection circuit diagram in the second embodiment of the present invention is shown.

[0019] Attached Figure 4 A set of experimental test data of the present invention is shown.

[0020] Among them: 1. Ultrasonic probe, 2a. Resistor, 2b. Resistor, 3. Switch, 4. Switch control signal, 5. Microcontroller, 6. Transistor, 7. EEPROM. DETAILED DESCRIPTION

[0021] In one embodiment, Figure 1 and 2 , a detection circuit for optimizing a detection method for residual vibration frequency, the detection circuit used includes a driving circuit, the driving circuit is connected to an ultrasonic probe 1 to be detected, the ultrasonic probe 1 is externally connected to a signal processing device, two parallel resistors 2a and 2b are arranged between the ultrasonic probe 1 and the signal processing device, one of the resistors 2b is connected to a microcontroller 5, and controls a switch 3 connected to the detection circuit; the detection method is as follows: The first step is to detect the residual vibration frequency and obtain the test results; The second step is to judge the test result, whether the frequency deviation rate is less than the standard value, and if it is less than the standard value, the test is judged to be qualified and the test is completed; when the frequency deviation rate is greater than the standard value, the switch is disconnected by the microcontroller, and one of the two parallel resistors is disconnected, so that the resistance in the detection circuit increases; The third step is to perform the residual vibration frequency test again to obtain the secondary test result; The fourth step is to compare the result with the standard value to see if the frequency deviation rate is less than the standard value. If it is less than the standard value, the test is considered qualified and the test is completed; when the frequency deviation rate is greater than the standard value, the test is considered unqualified and the product is scrapped.

[0022] In one embodiment, Figure 1 and 3A detection circuit for optimizing a detection method for residual vibration frequency includes a driving circuit, the driving circuit is connected to an ultrasonic probe 1 to be detected, the ultrasonic probe 1 is externally connected to a signal processing device, and a resistor 2a and a transistor 6 connected in parallel are arranged between the ultrasonic probe 1 and the signal processing device, wherein one transistor 6 is connected to a microcontroller 5 through an EEPROM 7 to control the opening and closing of the transistor 6. The transistor 6, the EEPROM 7 and the microcontroller 5 are all integrated inside the detection chip, and the detection method is the same as that of the first embodiment.

[0023] The specific experimental data are as follows: in one group, the parallel resistances are 4.1KΩ and 8.2KΩ respectively, and the standard value of the measured results is a frequency deviation of 9.36%. Therefore, the test record is labeled "00", and the result is no greater than 3.12%; labeled "01", the result is no greater than 6.24%; labeled "10", the result is no greater than 9.36%; labeled "11", the result is greater than 9.36%.

[0024] In summary, when the chip with number 11 appears, the result is judged as unqualified, and the remaining numbers are all qualified. Figure 4 shown.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than a limiting technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A detection circuit for optimizing a detection method for residual vibration frequency, characterized in that: It includes a driving circuit, the driving circuit is connected to the ultrasonic probe to be detected, the ultrasonic probe is externally connected to a signal processing device, two parallel resistors are arranged between the ultrasonic probe and the signal processing device, one of the resistors is connected to a microcontroller to control a switch connected to the detection circuit; The detection method is as follows: The first step is to detect the residual vibration frequency and obtain the test results; The second step is to judge the test result, whether the frequency deviation rate is less than the standard value. If it is less than the standard value, the test is considered qualified and the test is completed; When the frequency deviation rate is greater than the standard value, the switch is disconnected by the microcontroller, and one of the two resistors connected in parallel is disconnected, so that the resistance in the detection circuit increases; The third step is to perform the residual vibration frequency test again to obtain the secondary test result; The fourth step is to compare the result with the standard value to see if the frequency deviation rate is less than the standard value. If it is less than the standard value, the test is considered qualified and the test is completed; when the frequency deviation rate is greater than the standard value, the test is considered unqualified and the product is scrapped.

2. A detection circuit for optimizing residual vibration frequency according to claim 1, characterized in that: In the detection circuit, the two parallel resistors may be resistors with the same resistance value or resistors with different resistance values.

3. The detection circuit for optimizing the residual vibration frequency according to claim 1, characterized in that: The resistor connected to the microcontroller is replaced by a transistor.

4. The detection circuit for optimizing the residual vibration frequency according to claim 3, characterized in that: The transistor is connected to an EEPROM (Electrically Erasable Programmable Read-Only Memory).

5. The detection circuit for optimizing residual vibration frequency according to claim 1, characterized in that: The signal processing device and the microcontroller are both integrated inside the detection chip.

6. The detection circuit for optimizing residual vibration frequency according to claim 4, characterized in that: The EEPROM and transistor are both integrated inside the detection chip.

7. The method for optimizing the residual vibration frequency according to claim 1, characterized in that: The standard values ​​used for detection are the standard values ​​for residual vibration detection of ultrasonic waves of various specifications, which are used by manufacturers to determine whether ultrasonic sensors are qualified.

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