Vehicle body clearance surface difference measuring method and system based on robot cooperative follow-up

Abstract

The invention relates to the technical field of vehicle body clearance and surface difference measurement, and discloses a vehicle body clearance and surface difference measurement method and system based on robot collaborative follow-up. And then the multiple robots adjust and carry the cameras to collect vehicle body data of all measuring points on the vehicle head, the vehicle tail, the vehicle roof and the two sides of the vehicle body according to the pose transformation matrix, and a gap plane difference result is calculated. On-line accompanying measurement of the gap surface difference of the vehicle body is realized by adopting a mode of cooperative work of a plurality of robots, the production takt is not occupied, and the on-line measurement requirement of a line body can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle body gap and flush measurement, and particularly to a method and system for measuring vehicle body gap and flush based on robot collaborative follow-up. Background Art

[0002] With the profound transformation that the automotive manufacturing industry is undergoing, the traditional automotive industrial pattern is being reshaped by the rapid development of technologies such as artificial intelligence, Internet of Things, and new energy. In vehicle quality measurement, gap and flush involve multiple aspects such as vehicle appearance quality and vehicle sealing performance, and are key factors in ensuring vehicle quality. However, a vehicle has multiple types of gaps and flushes, multiple vehicle body colors, and high production rhythm requirements.

[0003] Currently, in vehicle production and manufacturing quality measurement, the measurement of gap and flush mainly uses the traditional method of manually using a thickness gauge to measure all types of gaps and flushes, or uses a handheld gap and flush measurement sensor for on-line dynamic or static measurement through manual operation or by installing it at the end of the robot flange, or achieves the purpose of gap measurement by installing a 3D sensor at the end of the robot flange for on-line measurement in a static or dynamic manner. In practice, the traditional manual measurement method has problems such as slow measurement, inconvenient measurement at individual measurement points, and low measurement efficiency; handheld gap measurement equipment usually has a high cost, and when manually held for inspection, it is time-consuming and requires a dedicated person to complete this task; while the static measurement method using a robot carrying a 3D structured light sensor requires occupying the production rhythm and has a relatively high cost, and the current method of using a robot carrying a 3D laser camera for dynamic measurement is affected by the position of the incoming vehicle body, and the stability cannot be guaranteed. Therefore, there is an urgent need to provide a measurement method that can not only ensure the production rhythm but also achieve good measurement results within a controllable cost budget. Summary of the Invention

[0004] The present invention provides a method and system for measuring vehicle body gap and flush based on robot collaborative follow-up to solve the problems in the above background art.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] In a first aspect, the present invention provides a method for measuring vehicle body gap and flush based on robot collaborative follow-up, which is applied to a system for measuring vehicle body gap and flush based on robot collaborative follow-up. The system includes a transfer roller table, multiple robots arranged on both sides of the transfer roller table, a code reader arranged on one side of the transfer roller table, and an encoder group arranged on the transfer roller table; the method includes:

[0007] S1: When the vehicle body flows into the measurement station, the code reader reads the vehicle body information and tracks the vehicle body position based on the vehicle body information and the encoder;

[0008] S2: When the vehicle body moves to the set position, trigger the cameras on both sides of the transfer roller table to collect vehicle body data according to the vehicle body information and the value of the encoder.

[0009] S3: Perform data splicing on the vehicle body data to generate a vehicle body point cloud, and estimate the vehicle body pose through the point cloud features of the vehicle body point cloud to obtain the current vehicle body pose.

[0010] S4: Perform matrix solution on the current vehicle body pose and the standard vehicle body pose to obtain a pose transformation matrix, and send the pose transformation matrix to multiple robots on both sides of the transfer roller table.

[0011] S5: Multiple robots adjust to carry cameras to collect the gap surface difference data of all measurement points on the front, rear, top, and both sides of the vehicle body according to the pose transformation matrix.

[0012] In a second aspect, the present application also provides a vehicle body gap surface difference measurement system based on robot collaborative follow-up. The system includes a transfer roller table, multiple robots arranged on both sides of the transfer roller table, a code reader arranged on one side of the transfer roller table, an encoder group arranged on the transfer roller table, and a processor. The processor is used to execute the following steps:

[0013] S1: When the vehicle body flows into the measurement station, control the code reader to read the vehicle body information, and track the vehicle body position based on the vehicle body information and the encoder.

[0014] S2: When the vehicle body moves to the set position, trigger the cameras on both sides of the transfer roller table to collect vehicle body data according to the vehicle body information and the value of the encoder.

[0015] S3: Perform data splicing on the vehicle body data to generate a vehicle body point cloud, and estimate the vehicle body pose through the point cloud features of the vehicle body point cloud to obtain the current vehicle body pose.

[0016] S4: Perform matrix solution on the current vehicle body pose and the standard vehicle body pose to obtain a pose transformation matrix, and send the pose transformation matrix to multiple robots on both sides of the transfer roller table.

[0017] S5: Control multiple robots to adjust to carry cameras to collect all measurement point vehicle body data on the front, rear, top, and both sides of the vehicle body according to the pose transformation matrix, and calculate the gap surface difference result.

[0018] Beneficial effects:

[0019] The method for measuring the body gap and surface difference based on robot collaborative follow-up provided by the present invention drives the vehicle body to move in the conveying direction through a transfer roller path. First, the pose transformation matrix during the movement is calculated, and then multiple robots are used to adjust the cameras carried according to the pose transformation matrix to collect the vehicle body data of all measurement points at the front of the vehicle, the rear of the vehicle, the roof, and both sides of the vehicle body, and calculate the gap and surface difference results. In this way, the on-line follow-up measurement of the body gap and surface difference is realized by using the collaborative work of multiple robots, without occupying the production rhythm, and the on-line measurement requirements of the line body can be met.

[0020] In a further solution, through hand-eye calibration and joint calibration of the positioning camera, the follow-up pose deviation of the robot is corrected to eliminate the position deviation of the incoming vehicle body.

[0021] In a further solution, through the follow-up encoder and the control system, the connection and linkage with the production line are realized, which can cope with different production line situations and ensure the effectiveness of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of a system for measuring the body gap and surface difference based on robot collaborative follow-up according to a preferred embodiment of the present invention;

[0023] Figure 2 It is one of the flowcharts of a method for measuring the body gap and surface difference based on robot collaborative follow-up according to a preferred embodiment of the present invention;

[0024] Figure 3 It is the second flowchart of a method for measuring the body gap and surface difference based on robot collaborative follow-up according to a preferred embodiment of the present invention.

[0025] REFERENCE SIGNS:

[0026] 1. Encoder group; 2. 3D structured light sensor; 3. Code reader; 4. Robot base; 5. Robot control cabinet; 6. Industrial control cabinet; 7. Electrical control cabinet; 8. Safety fence; 9. Robot; 10. 3D laser sensor; 11. Display screen; 12. Photoelectric sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a quantity limitation, but mean that there is at least one. The terms "connected" or "coupled" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0029] It should be understood that in the assembly process of the automobile production line, in the existing body gap and flushness measurement technology, there are problems such as a large number of body colors, a large number of measurement points, and a large measurement target area, resulting in low measurement efficiency, difficult measurement, and low measurement accuracy. Therefore, the present invention proposes a method for measuring the body gap and flushness based on robot collaborative follow-up.

[0030] This method is applied to a body gap and flushness measurement system based on robot collaborative follow-up. Please refer to Figure 1 , this system includes a robot base 4 installed inside the safety fence 8, an industrial robot 9 installed on the robot base 4, a 3D laser sensor 10 installed at the end of the robot 9, a robot control cabinet 5 installed in the middle of the robot base 4, 3D structured light sensors 2 installed on both sides of the transfer roller conveyor, photoelectric sensors 12 installed on both sides of the roller conveyor, an RFID reader 3 installed on one side of the transfer roller conveyor, an encoder assembly installed below the transfer roller conveyor, as well as an industrial computer and an industrial computer cabinet 6, an electrical control cabinet 7, and a display screen 11 above the production line at the measurement station and the station conveyor.

[0031] The transfer roller conveyor is used to drive the body to move in the conveying direction. The industrial robot 9 is used to carry the 3D laser camera to move. The 3D laser camera is used to collect point cloud data of the gap and flushness points. The 3D laser cameras on both sides of the transfer roller conveyor are used to collect body feature data for body pose estimation. The RFID is used to read body-related information. The display screen 11 is used to graphically display the measurement results.

[0032] Please refer to Figure 2 , a method for measuring the body gap and flushness based on robot collaborative follow-up provided by the present application is applied to a body gap and flushness measurement system based on robot collaborative follow-up. The system includes a transfer roller conveyor, multiple robots 9 arranged on both sides of the transfer roller conveyor, a reader 3 arranged on one side of the transfer roller conveyor, and an encoder group arranged on the transfer roller conveyor. The method includes:

[0033] S1: When the vehicle body enters the measurement station, the code reader 3 reads the vehicle body information and tracks the position of the vehicle body based on the vehicle body information and the encoder.

[0034] S2: When the vehicle body moves to the set position, cameras on both sides of the transfer roller table are triggered according to the vehicle body information and the values of the encoder to collect vehicle body data.

[0035] S3: The vehicle body data is stitched to generate a vehicle body point cloud, and the pose of the vehicle body is estimated through the point cloud features of the vehicle body point cloud to obtain the current vehicle body pose.

[0036] In this step, the point cloud features include the height (longitudinal) change data of the vehicle, the vehicle angle data, and the left - right (lateral) change data of the vehicle.

[0037] S4: The matrix solution is performed between the current vehicle body pose and the standard vehicle body pose to obtain a pose transformation matrix, and the pose transformation matrix is sent to multiple robots 9 on both sides of the transfer roller table.

[0038] In this step, the detailed steps of the matrix solution include:

[0039] Regarding the current vehicle body pose as A and the standard vehicle body pose as B, the formula for the matrix solution satisfies AX = B, where X is the obtained pose transformation matrix. Further, the pose transformation matrix X is sent to multiple robots 9 on both sides of the transfer roller table.

[0040] S5: Multiple robots 9 adjust to collect vehicle body data of all measurement points on the front, rear, top, and both sides of the vehicle body with cameras carried according to the pose transformation matrix, and calculate the gap surface difference result.

[0041] The above - mentioned method for measuring the vehicle body gap surface difference based on robot collaborative follow - up drives the vehicle body to move in the conveying direction through the transfer roller table. First, the pose transformation matrix during the movement is calculated, and then multiple robots 9 adjust to collect vehicle body data of all measurement points on the front, rear, top, and both sides of the vehicle body with cameras carried according to the pose transformation matrix, and calculate the gap surface difference result. In this way, the on - line follow - up measurement of the vehicle body gap surface difference is realized by adopting the method of multiple robots working together, without occupying the production beat, and can meet the on - line measurement requirements of the production line.

[0042] Next, as Figure 3 shown, a complete example is used to describe the steps of the above - mentioned method for measuring the vehicle body gap surface difference based on robot collaborative follow - up in detail as follows:

[0043] Step 1: After installing equipment such as the robot base 4, industrial robot 9, follow - up encoder, 3D camera, induction switch, and industrial computer, perform tests such as zero calibration of robot 9, hand - eye calibration of the laser camera robot 9, combined calibration of the deviation - correcting structured light camera and the laser camera, and follow - up teaching of robot 9.

[0044] Step 2: After Step 1 is completed, the vehicle body is grabbed by the robot 9 at the front-end process station and placed on the conveyor line. Before flowing into the measurement station, the measurement system senses the arrival position of the vehicle body through the line body photoelectric sensor 12. When the vehicle body is sensed, an induction signal is output to notify the measurement system to obtain the current encoder value and perform vehicle body travel position tracking.

[0045] Step 3: When the vehicle body flows into the measurement station, the photoelectric sensor 12 senses that the vehicle enters the measurement station, and the system triggers the RFID reader 3 to work, synchronously reads the vehicle information. Further, the system accesses the SMO platform according to the encoded information read by the RFID, and obtains information such as the vehicle model, body color, and suspension version according to the vehicle VIN number and feeds it back to the measurement system; further, the measurement system tracks the vehicle position through the encoder.

[0046] It is worth pointing out that the VIN code is a string of numbers and characters, which contains information such as vehicle model, configuration, and color.

[0047] Step 4: When the vehicle body travels to the position where the 3D structure camera collects data, the system triggers the positioning cameras on both sides of the conveyor line to collect vehicle body data according to the RFID information and the value of the tracking encoder. After the data collection is completed, the data is spliced to generate a vehicle body point cloud. The vehicle body pose is estimated through the point cloud features to obtain the current vehicle body pose. By performing matrix solution with the standard vehicle body pose P, a pose transformation matrix T of the vehicle body is obtained, and this matrix is sent to the 4 robots 9 on both sides of the conveyor line.

[0048] Step 5: When the system measures that the vehicle body travels to the position where the 3D laser camera takes pictures, the robot 9 automatically adjusts the pose when carrying the camera to collect the gap surface difference data of all measurement points on the front, rear, top, and both sides of the vehicle body according to the deviation correction data (referring to the transformation matrix T) and information such as vehicle model and body color feedback by the system in Step 4. After the robot 9 runs to each point position, it performs follow-up tracking according to the value of the encoder, and the measurement system performs on-line data collection and real-time data analysis.

[0049] In this step, the following method of the robot 9 is that when the vehicle body passes through the opposed sensor, a signal is output to the 4 robots 9. The robot 9 records the encoder value of the following starting point. When the vehicle body enters the reach range of the robot 9, the robot 9 starts to follow the vehicle body for measurement. In this embodiment, all measurement points of the vehicle body are divided according to the working range of the robot 9 to ensure that there is no crossover situation for the robot 9.

[0050] In this step, the 4 robots work together without interfering with each other, carry cameras to collect data of different measurement points, and achieve the effect of being relatively stationary with the vehicle body according to the position of the conveyor line input by the encoder in real time during the collection process.

[0051] In this step, the measurement system can adapt to different roller conveyor speeds, and adjust the timing of movement and following nodes according to different conveyor speeds; the measurement of the body gap and surface difference is completed after the body flows out of the measurement station at a constant or variable speed.

[0052] In this step, when the body is moving, if there is a normal stop of the conveyor line, the robot 9 automatically stops after identifying the measurable points, and after the conveyor line starts, the robot 9 starts to measure following the movement.

[0053] Furthermore, the gap measurement method is to scan the measurement point area data with a laser camera, extract the point cloud set of the gap from it, filter the point cloud set to remove abnormal point data, fit a straight line on the point cloud, and determine the gap direction by finding the optimal direction vector, thereby obtaining the gap value.

[0054] In an example, the gap calculation steps are as follows:

[0055] (1) Preprocess the point cloud data, including filtering, smoothing, and clustering segmentation.

[0056] (2) After preprocessing, obtain the contour point cloud data at the left and right body gaps. Extract the contour endpoints from the left and right contour data respectively, and these endpoints are the key points for calculating the gap value.

[0057] (3) Calculate the Euclidean distance between the left and right endpoints, and project this distance onto the reference plane required by the process, which is the gap value.

[0058] In this way, referring to the actual manufacturing process and taking points in the way of simulating manual measurement can make the measurement more accurate without data compensation.

[0059] The surface difference measurement method is to scan the measurement point area with a laser camera to extract the surface difference point set, define the reference plane and the points to be measured according to the measurement specification, and calculate the surface difference value according to the point-to-plane measurement scheme.

[0060] In an example, the surface difference calculation steps are as follows:

[0061] (1) Determine which side, the left or the right, is the reference plane according to the process document

[0062] (2) For the point cloud contour determined as the reference plane, intercept a 10-mm ROI area starting from the endpoint, and for the point cloud contour of the non-reference plane, intercept a 5-mm ROI area starting from the endpoint.

[0063] (3) Calculate the center point coordinates of this area according to the 5-mm data, fit the reference line for the 10-mm data area, and the distance from the center point to the reference line is the surface difference. If the center point is below the reference plane, the surface difference is negative, otherwise it is positive.

[0064] Step 6: After all measurement points are measured, the vehicle body exits the measurement station. The system determines the measurement results, checks whether the determination results are qualified, outputs the determination information and displays it on the software platform. At the same time, the measurement results and the equipment operation status are synchronously transmitted to the SMO platform and visually displayed in the form of pictures on the large display screens 11 on both sides of the conveyor line for the convenience of the staff to view.

[0065] This application also provides a vehicle body gap and flushness measurement system based on robot collaborative follow-up. The system includes a transfer roller table, multiple robots 9 arranged on both sides of the transfer roller table, a code reader 3 arranged on one side of the transfer roller table, an encoder group arranged on the transfer roller table, and a processor. The processor is used to execute the following steps:

[0066] S1: When the vehicle body enters the measurement station, control the code reader 3 to read the vehicle body information and track the vehicle body position based on the vehicle body information and the encoder.

[0067] S2: When the vehicle body moves to the set position, trigger the cameras on both sides of the transfer roller table to collect vehicle body data according to the vehicle body information and the values of the encoders.

[0068] S3: Perform data stitching on the vehicle body data to generate a vehicle body point cloud, and estimate the vehicle body pose through the point cloud features of the vehicle body point cloud to obtain the current vehicle body pose.

[0069] S4: Solve the matrix between the current vehicle body pose and the standard vehicle body pose to obtain a pose transformation matrix, and send the pose transformation matrix to the multiple robots 9 on both sides of the transfer roller table.

[0070] S5: Control the multiple robots 9 to adjust the cameras carried to collect the vehicle body data of all measurement points on the front, rear, top, and both sides of the vehicle body according to the pose transformation matrix, and calculate the gap and flushness results.

[0071] Optionally, cameras are provided at the ends of the multiple robots 9.

[0072] In this example, the camera can be a 3D laser camera, a 3D structured light camera, a multi-line 3D laser camera, a binocular camera, or other similar 3D sensor acquisition devices that can achieve the same effect.

[0073] Optionally, the above system further includes a human-machine interaction large-screen display connected to the processor. Through the display, it is convenient for the staff to view the judgment results in a timely manner.

[0074] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field according to the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall fall within the protection scope determined by the claims.

Claims

1. A method for measuring the body gap and surface difference based on robot collaborative follow-up, which is applied to a body gap and surface difference measurement system based on robot collaborative follow-up. The system includes a transfer roller table, multiple robots arranged on both sides of the transfer roller table, a code reader arranged on one side of the transfer roller table, and an encoder group arranged on the transfer roller table; it is characterized in that, The method includes: S1: When the vehicle body flows into the measurement station, the code reader reads the vehicle body information, and based on the vehicle body information and the encoder, tracks the position of the vehicle body; S2: When the vehicle body travels to the set position, according to the vehicle body information and the values of the encoder, trigger the cameras on both sides of the transfer roller table to collect vehicle body data; S3: Perform data stitching on the vehicle body data to generate a vehicle body point cloud, and estimate the vehicle body pose through the point cloud features of the vehicle body point cloud to obtain the current vehicle body pose; S4: Perform matrix solution on the current vehicle body pose and the standard vehicle body pose to obtain a pose transformation matrix, and send the pose transformation matrix to multiple robots on both sides of the transfer roller table; S5: The multiple robots adjust to carry cameras to collect vehicle body data of all measurement points on the front, rear, roof, and both sides of the vehicle body according to the pose transformation matrix, and calculate the gap surface difference result.

2. The method for measuring the body gap and flushness based on robot collaborative follow-up according to claim 1, wherein The method further includes: S6: After all measurement points are measured, the vehicle body flows out of the measurement station, and determines whether the vehicle body is qualified according to the gap surface difference data of all measurement points, and displays the judgment result.

3. The method for measuring the body gap and flushness based on robot collaborative follow-up according to claim 1, wherein Before S1, the method further includes: Calibrating and teaching the multiple robots.

4. The method for measuring the body gap and flushness based on robot collaborative follow-up according to claim 1, wherein S1 includes: When it is sensed that the vehicle body enters the measurement station, trigger the code reader to work and synchronously read the vehicle information, and the vehicle information is the vehicle VIN number; And access the SMO platform according to the encoded information read by the code reader, obtain the vehicle model, body color, and suspension version information according to the vehicle VIN number, and feedback them to the measurement system; the measurement system tracks the vehicle position through the encoder.

5. The method for measuring the body gap and flushness based on robot collaborative follow-up according to claim 1, wherein S5 includes: The multiple robots automatically adjust to carry cameras to collect vehicle body data of all measurement points on the front, rear, roof, and both sides of the vehicle body according to the pose transformation matrix and the vehicle model and body color information, and calculate the gap surface difference result; After the robot runs to each point, perform follow-up tracking according to the value of the encoder. When the vehicle body passes through the opposed sensor, output a signal to the multiple robots. The multiple robots record the encoder value of the follow-up starting point. When the vehicle body enters the range of the robot's arm span, the robot starts to follow the vehicle body for measurement.

6. The method for measuring the body gap and flushness based on robot collaborative follow-up according to claim 1, characterized in that, Collecting all measurement point gap data in S5 includes: Scan the measurement point area data through the camera installed at the end of the robot, extract the point cloud set of the gap from it, filter the point cloud set, remove abnormal point data, and fit a straight line on the point cloud, and determine the gap direction by finding the optimal direction vector to obtain the gap value.

7. The method for measuring the body gap and flushness based on robot collaborative follow-up according to claim 1, characterized in that Collecting all measurement point surface difference data in S5 includes: Scan the measurement point area data through the camera installed at the end of the robot, extract the surface difference point set, define the reference plane and the measurement point to be measured according to the measurement specification, and calculate the surface difference value according to the point-to-plane measurement scheme.

8. A body gap and flush measurement system based on robot collaborative follow-up, characterized in that The system includes a transfer roller table, multiple robots arranged on both sides of the transfer roller table, a code reader arranged on one side of the transfer roller table, an encoder group arranged on the transfer roller table, and a processor. The processor is used to execute the following steps: S1: When the vehicle body flows into the measurement station, control the code reader to read the vehicle body information, and based on the vehicle body information and the encoder, track the position of the vehicle body; S2: When the vehicle body moves to the set position, trigger the cameras on both sides of the transfer roller table to collect vehicle body data according to the vehicle body information and the value of the encoder; S3: Stitch the vehicle body data to generate a vehicle body point cloud, estimate the vehicle body pose through the point cloud features of the vehicle body point cloud to obtain the current vehicle body pose; S4: Solve the matrix of the current vehicle body pose and the standard vehicle body pose to obtain a pose transformation matrix, and send the pose transformation matrix to multiple robots on both sides of the transfer roller table; S5: Control the multiple robots to adjust the vehicle body data collected by the cameras carried by them according to the pose transformation matrix for all measurement points on the front, rear, roof, and both sides of the vehicle body, and calculate the gap surface difference result.

9. The body clearance and surface difference measurement system based on robot collaborative follow-up according to claim 8, characterized in that, Cameras are provided at the ends of the multiple robots.

10. The body gap and flushness measurement system based on robot collaborative follow-up according to claim 8, wherein It also includes a human-machine interaction display connected to the processor for assisting manual sampling inspection and re-inspection.

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