CN108801133B - Method for detecting vehicle body characteristic line position drop - Google Patents

Abstract

According to an embodiment of the present invention, a method for detecting a vehicle body characteristic line position drop is provided, including: making section lines perpendicular to the characteristic lines at the matching positions of the characteristic lines; determining a starting point and an end point of the characteristic line on the section line; determining a comparison reference point on the section line according to the starting point and the end point; the positional drop of the characteristic line is determined based on the comparison reference point. The detection method of the vehicle body characteristic line position drop can determine comparison reference points in a unified mode, and each comparison reference point is placed in the same reference coordinate system, so that quantized position drop data can be obtained, and evaluation and correction are facilitated.

Description

Detection method of position drop of body characteristic line

technical field

The invention relates to a detection technology in the process of automobile manufacturing, and more particularly, to a method for detecting the positional difference of a feature line of a vehicle body between different parts.

Background technique

With the change of people's aesthetics of automobile appearance and the improvement of stamping process, various decorative lines are used more and more on the body to decorate the appearance of the vehicle. At present, the body characteristic line (also known as the rib line or waist line) has become an indispensable feature in the design of automobile exterior. Figure 1 discloses a schematic diagram of the vehicle body characteristic lines involved in the whole vehicle design process.

However, the entire body is composed of multiple parts, such as four doors, front and rear covers, side panels, fenders, front and rear bumpers, and front and rear headlights. In order to pursue the beauty and integrity of the body appearance, the same feature Lines often run through several components. Figure 2 shows a schematic diagram of the same feature line running through several components. According to the design, the same feature line that runs through several parts should be continuous, that is, at the matching junction of each part, the body feature lines need to be aligned with each other. However, in fact, due to the deviation caused by the manufacturing and assembly process, when two adjacent parts are matched, the same feature line is often misaligned.

Figures 3a and 3b are schematic diagrams showing the position drop of the same feature line on different parts. Fig. 3b is a partial enlarged view of Fig. 3a. From the overall point of view, there is a positional gap between the feature lines on the two components and they are not aligned. However, since the feature line usually has a certain width, and the cross-section of the feature line is not a regular arc or regular geometric shape, it is difficult to determine the exact position of the feature line, and it is difficult to quantify the position drop of the feature line. Evaluation. This results in a very low correction efficiency for the problem of the position drop of the characteristic line. Since there is no accurate quantitative data, we can only rely on the overall observation to evaluate whether the feature lines are aligned, resulting in low evaluation accuracy and efficiency.

SUMMARY OF THE INVENTION

The present invention aims to provide a method capable of detecting the drop of the characteristic line of the vehicle body at the matching position of the vehicle body parts.

According to an embodiment of the present invention, a method for detecting a position drop of a characteristic line of a vehicle body is provided, including:

Make a section line perpendicular to the feature line at the matching position of the feature line;

Determine the start point and end point of the feature line on the section line;

determining a comparison reference point on the section line according to the starting point and the ending point;

The position drop of the feature line is determined based on the comparison reference point.

In one embodiment, the detection method further includes acquiring point cloud information on the surface of the vehicle body parts through an optical device, and performing the above detection method based on the point cloud information.

In one embodiment, determining the start and end points of the feature line on the section line includes:

Build a curvature value curve along the section line;

Find the sudden change point of the curvature of the section line, the sudden change point is the starting point and the end point of the characteristic line on the section line.

In one embodiment, determining the comparison reference point on the section line according to the start point and the end point includes:

Construct the starting point tangent at the starting point, the starting point tangent is tangent to the section line and the starting point is the tangent point;

Construct the end point tangent at the end point, the end point tangent is tangent to the section line and the end point is the tangent point;

Determine the intersection of the start point tangent and the end point tangent;

Determine the projection point of the intersection point on the section line, and the projection point is the reference point for comparison.

In one embodiment, determining the projection point of the intersection point on the section line includes:

Find the vertical line that passes through the intersection and is perpendicular to the section line;

The intersection of the vertical line and the section line is the projection point.

In one embodiment, the detection method further includes: setting a reference coordinate system, placing each comparison reference point in the reference coordinate system to obtain a coordinate value, and calculating a position drop value of the characteristic line based on the coordinate value.

The method for detecting the position difference of the vehicle body feature line of the present invention can determine the comparison reference points in a unified manner, and put each comparison reference point in the same reference coordinate system, and can obtain quantified position difference data, which is convenient for evaluation and correction.

Description of drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which like reference numerals refer to like features throughout, wherein:

Figure 1 discloses a schematic diagram of the vehicle body characteristic lines involved in the whole vehicle design process.

Figure 2 shows a schematic diagram of the same feature line running through several components.

Figures 3a and 3b are schematic diagrams showing the position drop of the same feature line on different parts.

FIG. 4 discloses a schematic diagram of a cross-sectional line of a feature line in a method for detecting a position drop of a feature line of a vehicle body according to an embodiment of the present invention.

5 discloses a schematic diagram of a curvature value curve of a cross-sectional line in a method for detecting a position drop of a characteristic line of a vehicle body according to an embodiment of the present invention.

6 discloses a schematic diagram of the starting point and the end point of the characteristic line in the method for detecting the position drop of the characteristic line of the vehicle body according to an embodiment of the present invention.

FIG. 7 discloses a schematic diagram of a starting point tangent and an ending point tangent in a method for detecting a position drop of a feature line of a vehicle body according to an embodiment of the present invention.

FIG. 8 discloses a schematic diagram of determining the intersection point of the starting point tangent and the ending point tangent in the method for detecting the position drop of the vehicle body characteristic line according to an embodiment of the present invention.

FIG. 9 shows a schematic diagram of determining a comparison reference point in a method for detecting a position drop of a characteristic line of a vehicle body according to an embodiment of the present invention.

FIG. 10 shows a schematic diagram of determining the position drop value in the method for detecting the position drop of the vehicle body feature line according to an embodiment of the present invention.

Detailed ways

The present invention aims to provide a method for detecting the positional difference of the characteristic line of the vehicle body. In one embodiment, the method includes the following steps:

102. Obtain point cloud information on the surface of body parts through optical equipment. In one embodiment, the detection method is based on point cloud information.

104. Make a section line perpendicular to the feature line at the matching position of the feature line. FIG. 4 discloses a schematic diagram of a cross-sectional line of a feature line in a method for detecting a position drop of a feature line of a vehicle body according to an embodiment of the present invention. Referring to FIG. 4 , at the matching positions of adjacent components, a section line 204 perpendicular to the feature line 202 is made. Usually the characteristic line has a curved surface, so the section line 204 is a curve.

106. Determine the start and end points of the feature line on the section line. In one embodiment, determining the start point and end point of the feature line on the section line includes the following steps:

Constructs a curvature value curve along the section line. 5 discloses a schematic diagram of a curvature value curve of a cross-sectional line in a method for detecting a position drop of a characteristic line of a vehicle body according to an embodiment of the present invention. Referring to FIG. 5 , a curvature value curve 206 is constructed along section line 204 .

Find the sudden change point of the curvature of the section line, the sudden change point is the starting point and the end point of the characteristic line on the section line. Since the feature line is protruding or recessed from the surface of the vehicle body, there is a relatively obvious demarcation at the junction between the feature line and the surface of the vehicle body. From the perspective of the curvature value curve of the section line, there is a sudden change in the section curvature at the junction between the characteristic line and the body surface. Therefore, the point where the curvature value of the section line suddenly changes is the start and end points of the characteristic line. 6 discloses a schematic diagram of the starting point and the end point of the characteristic line in the method for detecting the position drop of the characteristic line of the vehicle body according to an embodiment of the present invention. Referring to FIG. 6 , the starting point 208 and the ending point 210 of the characteristic line are determined according to the abrupt change point of the curvature value of the section line.

108. Determine the comparison reference point on the section line based on the start and end points. In one embodiment, determining the comparison reference point on the section line according to the start point and the end point includes the following steps:

Builds a start tangent at the start point, the start tangent is tangent to the section line and the start point is the tangent point.

Constructs an end tangent at the end point, where the end tangent is tangent to the section line and the end point is the tangent point.

FIG. 7 discloses a schematic diagram of a starting point tangent and an ending point tangent in a method for detecting a position drop of a feature line of a vehicle body according to an embodiment of the present invention. Referring to FIG. 7, a starting point tangent 212 is constructed at the starting point 208, the starting point tangent 212 is tangent to the section line 204 and the starting point 208 is the tangent point. An end point tangent 214 is constructed at the end point 210, the end point tangent 214 being tangent to the section line 204 and the end point 210 being the tangent point.

Determines the intersection of the start and end tangents. FIG. 8 discloses a schematic diagram of determining the intersection point of the starting point tangent and the ending point tangent in the method for detecting the position drop of the vehicle body characteristic line according to an embodiment of the present invention. The starting point tangent 212 and the ending tangent 214 are respectively extended toward the inside (the inside refers to the direction toward the inside of the characteristic line), and the intersection 216 of the starting tangent 212 and the ending tangent 214 is determined.

Determine the projection point of the intersection point on the section line, and the projection point is the reference point for comparison. FIG. 9 shows a schematic diagram of determining a comparison reference point in a method for detecting a position drop of a characteristic line of a vehicle body according to an embodiment of the present invention. In one embodiment, determining the projection point of the intersection point on the section line includes the step of finding a vertical line passing through the intersection point 216 and perpendicular to the section line. The intersection of the vertical line with the section line 204 is the projection point 218 .

110. Determine the position drop of the feature line based on the comparison reference point. In one embodiment, the detection method further includes the steps of: setting a reference coordinate system, placing each comparison reference point in the reference coordinate system to obtain coordinate values, and calculating the position drop value of the characteristic line based on the coordinate values. FIG. 10 shows a schematic diagram of determining the position drop value in the method for detecting the position drop of the vehicle body feature line according to an embodiment of the present invention. Referring to FIG. 10 , the comparison reference point A of the front door component has a Z coordinate of +706.44mm in the reference coordinate system, and the comparison reference point B of the rear door component has a Z coordinate of +704.10mm in the reference coordinate system. Since the comparison reference points A and B are placed in the same reference coordinate system, it can be determined that there is a position drop between the comparison reference points A and B in the Z direction, and the position drop value is (706.44-704.10) mm. According to the above position drop value, the components can be adjusted so that the comparison reference points of each component are aligned with each other.

The method for detecting the position difference of the vehicle body feature line of the present invention can determine the comparison reference points in a unified manner, and put each comparison reference point in the same reference coordinate system, and can obtain quantified position difference data, which is convenient for evaluation and correction.

The above-mentioned embodiments are provided for those skilled in the art to realize or use the present invention. Those skilled in the art can make various modifications or changes to the above-mentioned embodiments without departing from the inventive concept of the present invention. The protection scope of the present invention is not limited by the above-mentioned embodiments, but should be the maximum scope conforming to the innovative features mentioned in the claims.

Claims (4)

1. a detection method for the position drop of the characteristic line of a vehicle body, is characterized in that, comprises: Make a section line perpendicular to the feature line at the matching position of the feature line; Determining the starting point and the end point of the characteristic line on the section line includes: constructing a curvature value curve along the section line; finding the mutation point of the curvature of the section line, where the mutation point is the start point and the end point of the characteristic line on the section line; Determining the comparison reference point on the section line according to the starting point and the ending point, including: constructing a starting point tangent at the starting point, the starting point tangent is tangent to the section line, and the starting point is a tangent point; constructing an ending point tangent at the end point, the ending point tangent Tangent to the section line and the end point is the tangent point; determining the intersection of the start point tangent and the end point tangent; determining the projection point of the intersection point on the section line, and the projection point is a comparison reference point; The position drop of the feature line is determined based on the comparison reference point. 2 . The method for detecting the position drop of the vehicle body feature line according to claim 1 , further comprising obtaining point cloud information on the surface of the vehicle body parts through an optical device, and performing the detection method based on the point cloud information. 3 . 3. The method for detecting the position drop of the characteristic line of the vehicle body as claimed in claim 1, wherein determining the projection point of the intersection point on the section line comprises: Find the vertical line that passes through the intersection and is perpendicular to the section line; The intersection of the vertical line and the section line is the projection point. 4. The method for detecting the position difference of the vehicle body characteristic line as claimed in claim 1, characterized in that, further comprising: Set the reference coordinate system, place each comparison reference point in the reference coordinate system to obtain the coordinate value, and calculate the position drop value of the characteristic line based on the coordinate value.

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