An automobile body repair trace detection device and method

Abstract

The present invention relates to the technical field of vehicle detection, and discloses a vehicle body repair trace detection device and method. The detection method includes the following steps: Step 1: Collect signals; Step 2: Process signals; Step 3: Evaluate results; Step 4: Locate repair traces. The detection device includes a single-chip microcomputer, a signal acquisition module, a signal processing module, a defect location module, and a display module. The signal acquisition module is used to collect the voltage signal of the magnetic field of the vehicle body. The signal processing module is used to calculate and process the voltage signal of the magnetic field of the vehicle body collected by the signal acquisition module into a characteristic curve. 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 used to display the characteristic curve and output and display the evaluation result. The vehicle body repair trace detection device and method have a fast detection speed, are comprehensive and without omission in detection, have no detection blind area, and have high detection accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of used car detection, and particularly to a detection device and method for automobile body repair traces. Background Art

[0002] In the used car market, if a vehicle has experienced a major collision accident, its body structure often poses potential safety hazards. Even after being processed by means such as sheet metal repair and welding, the safety of the vehicle will still be significantly reduced, and its value in the used car transaction will also be greatly discounted. Traditional detection methods, such as using a paint thickness gauge, although can detect some repair traces of the car, but this method has limitations: it can only detect selected points, with low detection efficiency and prone to missing other potential problem areas.

[0003] More troublesome is that with the progress of repair technology, such as the use of non-putty sheet metal repair and other means, these advanced repair methods can cleverly avoid the detection of the paint thickness gauge, 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 becomes more complex and difficult, and buyers may face higher risks when purchasing a car.

[0004] Therefore, a detection device and method for automobile body repair traces are provided to solve the above problems. Summary of the Invention

[0005] To make up for the above deficiencies, the present invention provides a detection method for automobile body repair traces, including the following steps:

[0006] Step 1: Signal acquisition

[0007] A detection sensor including an induced sensor and an induction sensor is evenly swept across the surface of the automobile body to be detected, a transient multi-frequency electromagnetic signal is input into the induced sensor of the detection sensor, and a voltage signal of the composite magnetic field of the automobile body is collected through the induction sensor.

[0008] Step 2: Signal processing

[0009] The received voltage signal is divided into several groups of voltage values according to the time relationship, a signal attenuation curve is obtained through the several groups of voltage values, effective data in the signal attenuation curve are screened to obtain an effective attenuation curve, one of the effective signal attenuation curves is selected as a reference curve, the voltage values of the remaining effective signal attenuation curves are divided by the voltage value corresponding to the reference curve to obtain a preprocessed eigenvalue, the preprocessed eigenvalue is divided by the standard voltage value to obtain a final eigenvalue, a characteristic curve is constructed with time as the abscissa and the final eigenvalue as the ordinate, the peaks and valleys of the characteristic curve are judged, and the maximum value of the peak of the characteristic curve and the minimum value of the valley of the characteristic curve are selected;

[0010] Step 3: Result evaluation

[0011] Set a defect threshold. 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 indicates that there are no repair marks on the surface of the car 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 indicates that there are repair marks on the surface of the car body.

[0012] Step Four: Locate the repair marks

[0013] Mark the horizontal coordinate time range corresponding to the vertical coordinate value of the characteristic curve exceeding the defect threshold. The position on the surface of the car body scanned by the detection sensor corresponding to this time range is the position where the repair marks on the car body are located.

[0014] Furthermore, as a supplement to the above technical solution, the method for screening the effective data in the signal attenuation curve to obtain the effective attenuation curve in Step Two is as follows: The method for screening the effective data in the signal attenuation curve to obtain the effective signal attenuation curve in Step Two is characterized in that: delete the first 5 groups of invalid voltage values in the signal attenuation curve, define that the voltage values with a slope of 0 to 1 in the signal attenuation curve are all valid voltage values, define the second voltage value after the valid voltage value as the last valid voltage value, delete all the voltage values after the last valid voltage value in the signal attenuation curve, and the remaining voltage values after deleting all the voltage values before the first 5 groups and after the last valid voltage value form the effective attenuation curve.

[0015] Furthermore, as a supplement to the above technical solution, in Step One, the speed at which the detection sensor scans the surface of the car body to be detected uniformly is 3 m / min to 6 m / min.

[0016] Furthermore, as a supplement to the above technical solution, in Step Two, the standard voltage value is a set reference value, and the value is 5.

[0017] Furthermore, as a supplement to the above technical solution, the set defect threshold in Step Three is 4.5 to 5.75.

[0018] A detection device for repair marks on a car body includes a single-chip microcomputer, a signal acquisition module, a signal processing module, a defect location module, and a display module;

[0019] The signal acquisition module is electrically connected to the single-chip microcomputer. The signal acquisition module is used to collect the voltage signal of the magnetic field of the car body. The acquisition module includes a signal generator and a detection sensor, and the detection sensor is composed of an induced sensor and an induction sensor;

[0020] The signal processing module is electrically connected to the single-chip microcomputer. The signal processing module is used to arithmetically process the voltage signal of the magnetic field of the vehicle body collected by the signal acquisition module into a characteristic curve;

[0021] The defect location module is electrically connected to the single-chip microcomputer. The defect location module is used to set a defect threshold and mark the range where the characteristic curve exceeds the defect threshold;

[0022] The display module is electrically connected to the single-chip microcomputer. The display module is used to display the characteristic curve and output an evaluation result.

[0023] The present invention has the following beneficial effects:

[0024] The vehicle body repair trace detection device and method described in the present invention have a fast detection speed. For the detection of the vehicle body, it can be detected at a speed of 3 - 6 m / min, and the detection of the entire vehicle body can be completed within 30 minutes;

[0025] The vehicle body repair trace detection device and method described are comprehensive and without omission. Signals are transmitted and sensed through the induction sensor and the inductive sensor. Different from the conventional paint layer detection, the present invention performs detection in a mobile detection manner, detects and records all positions on the moving path, and there is no detection blind area;

[0026] The vehicle body repair trace detection device and method described have high detection accuracy. Since it can distinguish the material grade and the resistance change caused by the change of the crystal structure, and the repair work cannot completely restore this part of the change, the present invention can effectively detect the problems in the positions with defects such as deformation, distortion, and welding. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the working process of a vehicle body repair trace detection method described in the present invention;

[0028] Figure 2 It is a system block diagram of a vehicle body repair trace detection device described in the present invention;

[0029] Figure 3 It is a characteristic curve diagram output after the wing panel body of a vehicle body with a twist deformation caused by a certain collision is detected by the present invention;

[0030] Figure 4 It is a characteristic curve diagram output after the door body of a vehicle body without twist deformation is detected by the present invention;

[0031] Figure 5 It is a characteristic curve diagram output after the front bumper body of a vehicle body with a twist deformation caused by a certain collision is detected by the present invention;

[0032] Figure 6 It is a characteristic curve graph output after detection by the present invention for a front engine hood after distortion repair.

[0033] Figure 7 It is a characteristic curve graph output after detection by the present invention for a rear bumper after collision distortion repair.

[0034] Wherein: Figures 3 to 7 The unit of the abscissa is time S, and the unit of the ordinate is voltage mV. Specific implementation mode

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0036] As Figure 1 shown, a method for detecting repair marks on an automobile body includes the following steps:

[0037] Step 1: Collect signals

[0038] A detection sensor including an inductive sensor and an induction sensor is swept across the surface of the automobile body to be detected at a uniform speed of 5 m / min, and a transient multi-frequency electromagnetic signal is input into the inductive sensor of the detection sensor, and the voltage signal of the composite magnetic field of the automobile body is collected through the induction sensor.

[0039] Step 2: Process signals

[0040] The received voltage signals are divided into several groups of voltage values according to the time relationship. A signal attenuation curve is obtained through the several groups of voltage values. The effective data in the signal attenuation curve is screened to obtain an effective attenuation curve. The first 5 groups of invalid voltage values in the signal attenuation curve are deleted. Each group of voltage values with a slope of 0 to 1 in the signal attenuation curve is defined as an effective voltage value. The second group of voltage values after the effective voltage value is defined as the last effective voltage value. All voltage values after the last effective voltage value in the signal attenuation curve are deleted. The remaining voltage values after deleting the first 5 groups and all voltage values after the last effective voltage value form an effective attenuation curve. One of the effective attenuation curves is selected as a reference curve. The voltage values of the remaining effective attenuation curves are divided by the corresponding voltage values of the reference curve to obtain a preprocessed characteristic value. The preprocessed characteristic value is divided by a standard voltage value to obtain a final characteristic value. The standard voltage value is a set reference value, and the numerical value of the standard voltage value is 5. A characteristic curve is constructed with time as the abscissa and the final characteristic value as the ordinate. The peaks and valleys of the characteristic curve are judged, and the maximum value of the peak of the characteristic curve and the minimum value of the valley of the characteristic curve are selected.

[0041] Step 3: Evaluation Results

[0042] Set the defect threshold 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 peak of the characteristic curve is less than or equal to 5.75, it indicates that there are no repair marks on the car body surface; if the minimum value of the trough of the characteristic curve is less than 4.5 or the maximum value on the peak of the characteristic curve is greater than 5.75, it indicates that there are repair marks on the car body surface;

[0043] Step 4: Repair Mark Location

[0044] Mark the horizontal coordinate time range corresponding to the vertical coordinate value of the characteristic curve exceeding the defect threshold. The position on the car body surface swept by the detection sensor corresponding to this time range is the location of the car body repair mark.

[0045] As Figure 2 shown, a car body repair mark detection device includes a single-chip microcomputer, a signal acquisition module, a signal processing module, a defect location module, and a display module;

[0046] The signal acquisition module is electrically connected to the single-chip microcomputer. The signal acquisition module is used to collect the voltage signal of the magnetic field of the car body. The acquisition module includes a signal generator and a detection sensor. The detection sensor is composed of an induced sensor and an induction sensor;

[0047] The signal processing module is electrically connected to the single-chip microcomputer. The signal processing module is used to process the voltage signal of the magnetic field of the car body collected by the signal acquisition module into a characteristic curve;

[0048] The defect location module is electrically connected to the single-chip microcomputer. The defect location module is used to set the defect threshold and mark the range where the characteristic curve exceeds the defect threshold;

[0049] The display module is electrically connected to the single-chip microcomputer. The display module is used to display the characteristic curve and output the evaluation result.

[0050] The characteristic curve output after detecting a fender car body with distortion caused by a certain collision by the above-mentioned car body repair mark detection device and method is as Figure 3 shown. In the range of the horizontal coordinate from 20 to 40, there are fluctuations between 4.7 and 5.5 in the curve. This reaction is that the car body is deformed, and after sheet metal repair, defect signal fluctuations can still be detected at the deformed position;

[0051] The characteristic curve output after detecting a door car body without distortion by the above-mentioned car body repair mark detection device and method is as Figure 4 shown. What is detected is a normal position that has not undergone repair, but the nearby structure is complex, which can reflect that the car body structure has no influence on the detection;

[0052] The characteristic curve output after detecting a front bumper body with distortion caused by a collision by the above-mentioned automotive body repair trace detection device and method is as follows Figure 5 shown. In the range of the abscissa from 5 to 7.5 s, the curve fluctuates downward to 4.2. This reaction indicates that when the body is deformed and after sheet metal repair, a defect signal fluctuation can still be detected at the deformed position; in the range of 10 to 12.5 s, the curve fluctuates downward to 3.8. This reaction indicates that when the body is cracked and after welding repair, a defect signal fluctuation is detected at the same position;

[0053] The characteristic curve output after detecting a front engine hood with distortion repaired by the above-mentioned automotive body repair trace detection device and method is as follows Figure 6 shown. At the abscissa from 15 to 23 s, the curve fluctuates downward to 4.1. This reaction indicates that when the body is deformed and after sheet metal repair, a defect signal fluctuation can still be detected at the deformed position;

[0054] The characteristic curve output after detecting a rear bumper with collision distortion repaired by the above-mentioned automotive body repair trace detection device and method is as follows Figure 7 shown. At the abscissa from 43 to 48 s, the curve fluctuates downward to 4.1. This reaction indicates that when the body is deformed and after welding repair, a defect signal fluctuation can still be detected at the deformed position.

[0055] Working principle:

[0056] The above-mentioned automotive body repair trace detection device sweeps uniformly across the surface of the automotive body to be detected. The single-chip microcomputer controls the signal generator to generate transient multi-frequency electromagnetic signals. The transient multi-frequency electromagnetic signals act on the induction sensor and generate an excitation magnetic field. The excitation magnetic field acts on the automotive 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 automotive body to form a composite magnetic field, and then the signal of the composite magnetic field of the automotive body is collected through the induction sensor;

[0057] The main materials of the automotive body are steel and aluminum. Generally, metal welding wires similar to the body material itself are used for welding repair. However, there are material differences between the welding wire and the body material itself, and there are obvious differences in electrical conductivity and magnetic conductivity. When the above-mentioned automotive body repair trace detection device and method detect the welding position, the eddy current will undergo obvious deformation, resulting in obvious attenuation or enhancement fluctuations in the feedback magnetic field signal;

[0058] Sheet metal repair, although the repaired surface is flat, after a vehicle collision, the relative positions of metal atomic layers change during the bending process of the metal, resulting in defects in the local crystal structure, increasing electron scattering, thereby increasing the resistance, and sheet metal repair does not restore the metal atoms to their original state. The described device and method for detecting repair marks on an automobile body will form eddy currents in the metal layer of the vehicle body, and the increased resistance of the metal at the bent position will affect the shape and intensity of the eddy currents, resulting in a detection signal at this position being different from that at other positions. Therefore, it can effectively detect the signal fluctuations caused by automobile body collisions.

[0059] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for detecting repair marks on an automobile body, characterized in that: It includes the following steps: Step 1: Signal acquisition: Uniformly sweep a detection sensor including an induced sensor and an induction sensor across the surface of the vehicle body to be detected, input a transient multi-frequency electromagnetic signal into the induced sensor of the detection sensor, and collect the voltage signal of the composite magnetic field of the vehicle body through the induction sensor; Step 2: Signal processing: Divide the received voltage signal into several groups of voltage values according to the time relationship, obtain a signal attenuation curve through the several groups of voltage values, screen the valid data in the signal attenuation curve to obtain a valid attenuation curve, select one of the valid signal attenuation curves as a reference curve, divide the voltage values of the remaining valid signal attenuation curves by the voltage values corresponding to the reference curve to obtain a preprocessing eigenvalue, divide the preprocessing eigenvalue by the standard voltage value to obtain a final eigenvalue, construct a characteristic curve with time as the abscissa and the final eigenvalue as the ordinate, judge the peaks and valleys of the characteristic curve, and select the maximum value of the peak of the characteristic curve and the minimum value of the valley of the characteristic curve; Step 3: Result evaluation: Set a defect threshold. If the minimum value of the valley of the characteristic curve is greater than or equal to the lower limit of the defect threshold and the maximum value of the peak of the characteristic curve is less than or equal to the upper limit of the defect threshold, it indicates that there is no repair trace on the surface of the vehicle body; If the minimum value of the valley of the characteristic curve is less than the lower limit of the defect threshold or the maximum value of the peak of the characteristic curve is greater than the upper limit of the defect threshold, it indicates that there is a repair trace on the surface of the vehicle body; Step 4: Repair trace positioning: Mark the time range of the abscissa corresponding to the value of the ordinate of the characteristic curve exceeding the defect threshold. The position of the surface of the vehicle body swept by the detection sensor corresponding to this time range is the position where the repair trace of the vehicle body is located; The method of screening the valid data in the signal attenuation curve to obtain a valid signal attenuation curve in Step 2 is: delete the first 5 groups of invalid voltage values in the signal attenuation curve, define that the voltage values of each group with a slope of 0 to 1 in the signal attenuation curve are valid voltage values, define the second group of voltage values after the valid voltage values as the last valid voltage value, delete all the voltage values after the last valid voltage value in the signal attenuation curve, and the remaining voltage values after deleting the first 5 groups and all the voltage values after the last valid voltage value form a valid attenuation curve; In Step 1, the speed at which the detection sensor uniformly sweeps across the surface of the vehicle body to be detected is 3 m / min to 6 m / min; In Step 2, the standard voltage value is a set reference value, and the value is 5; In Step 3, the set defect threshold is 4.5 to 5.

75.

2. An apparatus for implementing the method for detecting repair marks on an automobile body according to claim 1, characterized in that: It 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. The signal acquisition module is used to collect the voltage signal of the magnetic field of the vehicle body. The signal acquisition module includes a signal generator and a detection sensor. The detection sensor is composed of an induced sensor and an induction sensor; The signal processing module is electrically connected to the single-chip microcomputer. The signal processing module is used to operationally process the voltage signal of the magnetic field of the vehicle body collected by the signal acquisition module into a characteristic curve; The defect location module is electrically connected to the single-chip microcomputer, 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 microcomputer, and the display module is used to display the characteristic curve and output an evaluation result.

Images