Automobile body repair trace detection device and method

Abstract

The invention relates to the technical field of automobile detection, and discloses an automobile body repair trace detection device and method, and the detection method comprises the following steps: 1, collecting a signal; 2, processing the signal; 3, evaluating a result; 4, repairing trace positioning; the detection device comprises a single-chip microcomputer, a signal acquisition module, a signal processing module, a defect positioning module and a display module. The signal acquisition module is used for acquiring a voltage signal of an automobile body magnetic field, and the signal processing module is used for operating and processing the voltage signal of the automobile body magnetic field acquired by the signal acquisition module into a characteristic curve; the defect positioning module is used for setting a defect threshold value and marking the range of the characteristic curve exceeding the defect threshold value; and the display module is used for displaying the characteristic curve and outputting and displaying the evaluation result. The device and the method for detecting the repairing traces of the automobile body are high in detection speed, comprehensive in detection, free of omission, free of detection blind areas and high in detection precision.

Description

Technical Field

[0001] The present invention relates to the technical field of second-hand car detection, and in particular to a device and method for detecting automobile body repair traces. Background Art

[0002] In the used car market, if a vehicle has been involved in a major collision, its body structure often poses a safety hazard. Even after sheet metal repair and welding, the safety of the vehicle will still be greatly reduced, and its value in used car transactions will also be greatly reduced. Traditional detection methods, such as using a paint film meter, can detect some repair marks on the car, but this method has limitations: it can only detect selected points, the detection efficiency is low, and it is easy to miss other potential problem areas.

[0003] What is even more difficult is that with the advancement of repair technology, such as the use of putty-free sheet metal repair, these advanced repair methods can cleverly avoid the detection of paint film meters, making it difficult for inspectors to accurately judge the true condition of the vehicle. As a result, the evaluation of the overall condition of used cars has become more complicated and difficult, and buyers may face higher risks when purchasing cars.

[0004] To this end, a device and method for detecting automobile body repair marks are provided to solve the above-mentioned problems. Summary of the invention

[0005] In order to make up for the above shortcomings, the present invention provides a method for detecting automobile body repair traces, comprising the following steps: Step 1: Collect the signal A detection sensor including an inductive sensor and an inductive sensor is uniformly scanned over the surface of the automobile body to be detected, a transient multi-frequency electromagnetic signal is input to the inductive sensor of the detection sensor, and a voltage signal of the composite magnetic field of the automobile body is collected by the inductive sensor; Step 2: Process the signal Divide the received voltage signal into several groups of voltage values ​​according to the time relationship, obtain the signal attenuation curve through the several groups of voltage values, screen the valid data in the signal attenuation curve to obtain the effective attenuation curve, select one of the effective signal attenuation curves as the reference curve, divide the voltage values ​​of the remaining effective signal attenuation curves by the voltage value corresponding to the reference curve to obtain the preprocessing characteristic value, divide the preprocessing characteristic value by the standard voltage value to obtain the final characteristic value, construct the characteristic curve with time as the horizontal axis and the final characteristic value as the vertical axis, judge the peak and trough of the characteristic curve, and select the maximum value of the peak of the characteristic curve and the minimum value of the trough of the characteristic curve; Step 3: Evaluate the results A defect threshold is set. If the minimum value of the trough of the characteristic curve is greater than or equal to the lower limit of the defect threshold and the maximum value on the peak of the characteristic curve is less than or equal to the upper limit of the defect threshold, it means that there are no repair marks on the surface of the automobile body; if the minimum value of the trough of the characteristic curve is less than the lower limit of the defect threshold or the maximum value on the peak of the characteristic curve is greater than the upper limit of the defect threshold, it means that there are repair marks on the surface of the automobile body; Step 4: Repair trace positioning The horizontal axis time range corresponding to the vertical axis value of the characteristic curve exceeding the defect threshold is marked, and the position on the automobile body surface swept by the detection sensor corresponding to the time range is the position where the automobile body repair mark is located.

[0006] Further, as a supplement to the above technical solution, the method for filtering valid data in the signal attenuation curve in step 2 to obtain a valid attenuation curve is: It is characterized in that: the method for filtering valid data in the signal attenuation curve in step 2 to obtain a valid signal attenuation curve is: delete the first 5 groups of invalid voltage values ​​of the signal attenuation curve, define each group of voltage values ​​with a slope of 0~1 in the signal attenuation curve as a valid voltage value, define the second group of voltage values ​​after the valid voltage value as the last valid voltage value, delete all voltage values ​​after the last valid voltage value of the signal attenuation curve, and the remaining voltage values ​​after deleting the first 5 groups and all voltage values ​​after the last valid voltage value constitute the valid attenuation curve.

[0007] Further, as a supplement to the above technical solution, in step one, the speed at which the detection sensor uniformly scans the surface of the automobile body to be detected is 3m / min to 6m / min.

[0008] Further, as a supplement to the above technical solution, in step 2, the standard voltage value is a set reference value, which is 5; Further, as a supplement to the above technical solution, the defect threshold set in step three is 4.5~5.75.

[0009] An automobile body repair trace detection device includes a single chip microcomputer, a signal acquisition module, a signal processing module, a defect positioning module, and a display module; The signal acquisition module is electrically connected to the single-chip microcomputer, and is used to collect the voltage signal of the magnetic field of the automobile body. The acquisition module includes a signal generator and a detection sensor, and the detection sensor is composed of an inductive sensor and an inductive sensor; The signal processing module is electrically connected to the single chip computer, and the signal processing module is used to process the voltage signal of the magnetic field of the automobile body collected by the signal collection module into a characteristic curve; The defect location module is electrically connected to the single chip computer, and the defect location module is used to set a defect threshold and mark the range where the characteristic curve exceeds the defect threshold; The display module is electrically connected to the single chip computer, and is used to display characteristic curves and output evaluation results.

[0010] The present invention has the following beneficial effects: The automobile body repair trace detection device and method of the present invention has a fast detection speed. The automobile body detection can be performed at a speed of 3-6 m / min, and the entire vehicle body detection can be completed within 30 minutes. The automobile body repair trace detection device and method described above can detect comprehensively without omissions, and can transmit and sense signals through inductive sensors and inductive sensors. Different from conventional paint layer detection, the present invention can detect by mobile detection, detect and record all positions on the moving path, and there is no detection blind spot. The device and method for detecting automobile body repair marks have high detection accuracy. Since the material grade and resistance changes caused by crystal structure changes can be distinguished, and the repair work cannot completely restore these changes, the present invention can effectively detect problems at defective locations such as deformation, distortion, and welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of the working process of a method for detecting automobile body repair marks according to the present invention; Figure 2 This is a system block diagram of a vehicle body repair trace detection device described in the present invention; Figure 3 It is a characteristic curve diagram outputted after the fender body that is twisted and deformed due to a collision is detected by the present invention; Figure 4 It is a characteristic curve diagram outputted after a door body without distortion or deformation is detected by the present invention; Figure 5 A characteristic curve diagram outputted after the front bumper body is tested by the present invention due to distortion and deformation caused by a collision; Figure 6 A characteristic curve diagram outputted after a front engine cover with distortion and deformation is repaired and detected by the present invention; Figure 7 A characteristic curve diagram outputted after a rear bumper has been repaired after collision distortion and deformation and is detected by the present invention; in: Figures 3 to 7 The unit of the horizontal axis is time S, and the unit of the vertical axis is voltage mV. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] like Figure 1 As shown, a method for detecting automobile body repair traces comprises the following steps: Step 1: Collect the signal A detection sensor including an inductive sensor and an inductive sensor is scanned over the surface of the automobile body to be detected at a uniform speed of 5 m / min, a transient multi-frequency electromagnetic signal is input to the inductive sensor of the detection sensor, and a voltage signal of the composite magnetic field of the automobile body is collected by the inductive sensor; Step 2: Process the signal Divide the received voltage signal into several groups of voltage values ​​according to the time relationship, obtain the signal attenuation curve through the several groups of voltage values, screen the valid data in the signal attenuation curve to obtain the valid attenuation curve, delete the first 5 groups of invalid voltage values ​​of the signal attenuation curve, define each group of voltage values ​​with a slope of 0~1 in the signal attenuation curve as a valid voltage value, define the second group of voltage values ​​after the valid voltage value as the last valid voltage value, delete all voltage values ​​after the last valid voltage value of the signal attenuation curve, delete the first 5 groups and the remaining voltage values ​​after all the voltage values ​​after the last valid voltage value constitute the valid attenuation curve, select one of the valid attenuation curves as the reference curve, divide the voltage values ​​of the remaining valid attenuation curves with the voltage values ​​corresponding to the reference curve to obtain the preprocessing characteristic value, divide the preprocessing characteristic value with the standard voltage value to obtain the final characteristic value, the standard voltage value is the set reference value, the value of the standard voltage value is 5, construct the characteristic curve with time as the horizontal axis and the final characteristic value as the vertical axis, judge the peak and trough of the characteristic curve, and select the maximum value of the peak of the characteristic curve and the minimum value of the trough of the characteristic curve; Step 3: Evaluate the results The defect threshold is set to 4.5~5.75. If the minimum value of the trough of the characteristic curve is greater than or equal to 4.5 and the maximum value on the crest of the characteristic curve is less than or equal to 5.75, it means that there are no repair marks on the surface of the automobile body; if the minimum value of the trough of the characteristic curve is less than 4.5 or the maximum value on the crest of the characteristic curve is greater than 5.75, it means that there are repair marks on the surface of the automobile body; Step 4: Repair trace positioning The horizontal axis time range corresponding to the vertical axis value of the characteristic curve exceeding the defect threshold is marked, and the position on the automobile body surface swept by the detection sensor corresponding to the time range is the position where the automobile body repair mark is located.

[0014] like Figure 2 As shown, a vehicle body repair trace detection device includes a single chip microcomputer, a signal acquisition module, a signal processing module, a defect positioning module, and a display module; The signal acquisition module is electrically connected to the single-chip microcomputer, and is used to collect the voltage signal of the magnetic field of the automobile body. The acquisition module includes a signal generator and a detection sensor, and the detection sensor is composed of an inductive sensor and an inductive sensor; The signal processing module is electrically connected to the single chip computer, and is used to process the voltage signal of the magnetic field of the automobile body collected by the signal collection module into a characteristic curve; The defect location module is electrically connected to the single chip computer, and the defect location module is used to set a defect threshold and mark the range where the characteristic curve exceeds the defect threshold; The display module is electrically connected to the single chip computer, and is used to display characteristic curves and output evaluation results.

[0015] The characteristic curve outputted by the above-mentioned automobile body repair trace detection device and method after the fender body that was twisted and deformed due to a collision is as follows: Figure 3 As shown, within the range of 20 to 40 on the horizontal axis, the curve fluctuates between 4.7 and 5.5. This reflects that the body is deformed, and after sheet metal repair, the defect signal fluctuation can still be detected at the deformed position; The characteristic curve outputted by a vehicle door body without distortion and deformation after being detected by the above-mentioned vehicle body repair trace detection device and method is as follows: Figure 4 As shown, the detection is of a normal location that has not been repaired, but has a complex structure nearby, which shows that the vehicle body structure has no effect on the detection; The characteristic curve outputted by the above-mentioned automobile body repair trace detection device and method after the front bumper body that was twisted and deformed due to a collision is as follows: Figure 5 As shown, in the range of 5~7.5s on the horizontal axis, the curve fluctuates downward to 4.2. This reflects that the body is deformed, and the defect signal fluctuation can still be detected at the deformed position after sheet metal repair; in the range of 10~12.5s, the curve fluctuates downward to 3.8. This reflects that the body is cracked, and the defect signal fluctuation is detected at the same position after welding repair; A front hood is distorted and deformed after repair. The characteristic curve outputted after detection by the above-mentioned automobile body repair trace detection device and method is as follows: Figure 6 As shown, the curve fluctuates downward to 4.1 from 15 to 23 seconds on the horizontal axis. This reaction is that the body is deformed, and the defect signal fluctuation can still be detected at the deformed position after the sheet metal repair. A rear bumper with collision distortion and repair is detected by the above-mentioned automobile body repair trace detection device and method. The output characteristic curve is as follows: Figure 7 As shown, the curve fluctuates downward to 4.1 from the horizontal axis 43 to 48 seconds. This reaction is that the car body is deformed, and the defect signal fluctuation can still be detected at the deformed position after welding repair. Working principle:

[0016] The automobile body repair trace detection device is described. The surface of the automobile body to be detected is uniformly scanned by the single-chip microcomputer to control the signal generator to generate a transient multi-frequency electromagnetic signal. The transient multi-frequency electromagnetic signal acts on the inductive sensor and generates an excitation magnetic field. The excitation magnetic field acts on the automobile body and generates an induced eddy current. The induced eddy current generates a secondary induced magnetic field. The excitation magnetic field and the secondary induced magnetic field are superimposed on the automobile body to form a composite magnetic field. Then, the composite magnetic field signal of the automobile body is collected by the inductive sensor. The car body is mainly made of steel and aluminum. The metal welding wire used for welding repair is generally similar to the car body material. However, the welding wire and the car body material are different in material, and there are obvious differences in electrical conductivity and magnetic conductivity. The eddy current will undergo obvious deformation when the welding position is detected in the described car body repair trace detection device and method, resulting in obvious attenuation or enhancement fluctuations in the feedback magnetic field signal; Although the repaired surface of sheet metal is smooth, after a vehicle collision, the metal will change its relative position between the metal atomic layers during the bending process, causing defects in the local crystal structure, increasing electron scattering, and thus increasing resistance, and sheet metal repair will not restore the metal atoms to their original state. The described device and method for detecting traces of automobile body repair will form eddy currents in the metal layer of the vehicle body, and the increased metal resistance at the position after bending will affect the shape and intensity of the eddy current, causing the detection signal at this position to be different from that at other positions, so it can effectively detect signal fluctuations caused by automobile body collisions.

[0017] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting automobile body repair traces, characterized in that: The following steps are involved: Step 1: Collect the signal A detection sensor including an inductive sensor and an inductive sensor is uniformly scanned over the surface of the automobile body to be detected, a transient multi-frequency electromagnetic signal is input to the inductive sensor of the detection sensor, and a voltage signal of the composite magnetic field of the automobile body is collected by the inductive sensor; Step 2: Process the signal Divide the received voltage signal into several groups of voltage values ​​according to the time relationship, obtain the signal attenuation curve through the several groups of voltage values, screen the valid data in the signal attenuation curve to obtain the effective attenuation curve, select one of the effective signal attenuation curves as the reference curve, divide the voltage values ​​of the remaining effective signal attenuation curves by the voltage value corresponding to the reference curve to obtain the preprocessing characteristic value, divide the preprocessing characteristic value by the standard voltage value to obtain the final characteristic value, construct the characteristic curve with time as the horizontal axis and the final characteristic value as the vertical axis, judge the peak and trough of the characteristic curve, and select the maximum value of the peak of the characteristic curve and the minimum value of the trough of the characteristic curve; Step 3: Evaluate the results A defect threshold is set. If the minimum value of the trough of the characteristic curve is greater than or equal to the lower limit of the defect threshold and the maximum value on the peak of the characteristic curve is less than or equal to the upper limit of the defect threshold, it means that there is no trace of repair on the surface of the automobile body; If the minimum value of the trough of the characteristic curve is less than the lower limit of the defect threshold or the maximum value on the peak of the characteristic curve is greater than the upper limit of the defect threshold, it means that there are repair marks on the surface of the automobile body; Step 4: Repair trace positioning The horizontal axis time range corresponding to the vertical axis value of the characteristic curve exceeding the defect threshold is marked, and the position on the automobile body surface swept by the detection sensor corresponding to the time range is the position where the automobile body repair mark is located.

2. The method for detecting automobile body repair marks according to claim 1, characterized in that: In step 2, the method of filtering valid data in the signal attenuation curve to obtain a valid signal attenuation curve is as follows: delete the first 5 groups of invalid voltage values ​​of the signal attenuation curve, define each group of voltage values ​​with a slope of 0 to 1 in the signal attenuation curve as a valid voltage value, define the second group of voltage values ​​after the valid voltage value as the last valid voltage value, delete all voltage values ​​after the last valid voltage value of the signal attenuation curve, and the remaining voltage values ​​after deleting the first 5 groups and all voltage values ​​after the last valid voltage value constitute a valid attenuation curve.

3. The method for detecting automobile body repair marks according to claim 2, characterized in that: In step 1, the detection sensor uniformly scans the surface of the automobile body to be detected at a speed of 3m / min to 6m / min.

4. A method for detecting automobile body repair marks according to claim 3, characterized in that: In step 2, the standard voltage value is a set reference value, which is 5.

5. The method for detecting automobile body repair marks according to claim 4, characterized in that: The defect threshold set in step 3 is 4.5~5.

75.

6. A device for implementing the method for detecting automobile body repair marks according to any one of claims 1 to 5, characterized in that: It includes single chip microcomputer, signal acquisition module, signal processing module, defect location module and display module; The signal acquisition module is electrically connected to the single-chip microcomputer, and is used to collect the voltage signal of the magnetic field of the automobile body. The acquisition module includes a signal generator and a detection sensor, and the detection sensor is composed of an inductive sensor and an inductive sensor; The signal processing module is electrically connected to the single chip computer, and is used to process the voltage signal of the magnetic field of the automobile body collected by the signal collection module into a characteristic curve; The defect location module is electrically connected to the single chip computer, and the defect location module is used to set a defect threshold and mark the range where the characteristic curve exceeds the defect threshold; The display module is electrically connected to the single chip computer, and is used to display characteristic curves and output evaluation results.

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