An automatic lane marking following control system and method based on old line recognition

Abstract

This invention discloses an automatic road marking following control system and method based on old line recognition, belonging to the field of road marking construction technology. The system includes modules such as laser-assisted positioning, a vision sensor, boom position monitoring, audible and visual alarms, spray gun and status monitoring, glass bead application, and a human-machine interface display, as well as a control module. During operation, laser-assisted positioning guides the vehicle into position, the vision sensor acquires images of the old lines, and after image preprocessing and old line recognition, the calculation and control module calculates the adjustment amount of the boom and spray gun to control their precise positioning. Simultaneously, each monitoring module monitors the equipment status in real time; audible and visual alarms are triggered in case of abnormalities, and the spray gun applies the road markings when normal. After completion, the glass bead application module applies the beads. The human-machine interface display allows operators to view the system status, adjust parameters, and perform various operations. This invention can improve the accuracy, efficiency, stability, and quality of road marking construction, reduce labor intensity and costs, and is suitable for road marking maintenance and renewal operations.

Description

Technical Field

[0001] This invention relates to the field of road marking construction technology, and in particular to a control system and method that can identify old road markings through a vision system, automatically control the spray gun on the boom to follow the old road markings for operation, and has multiple intelligent monitoring and processing functions. Background Technology

[0002] In the maintenance and renewal of road markings, accurately applying new markings along existing ones is crucial for improving construction efficiency and quality. Traditional marking application methods often rely on manual labor, which is not only labor-intensive but also makes it difficult to guarantee the consistency and accuracy of the markings. With the development of automation technology, using vision systems to identify old markings and automatically control the spray gun to follow the application is becoming a trend. However, existing technologies still have shortcomings in terms of system stability, intelligence, and ability to handle complex situations. Summary of the Invention

[0003] The present invention aims to provide an automatic road marking following control system and method based on old line recognition, so as to solve the problems existing in the prior art and realize efficient, accurate and intelligent road marking construction operations.

[0004] An automatic lane marking following control system based on old line recognition includes: a laser-assisted positioning module, a vision sensor module, a boom position monitoring module, a human-machine interface display, an audible and visual alarm module, a spray gun and status monitoring module, and a glass bead spreading module.

[0005] The laser-assisted positioning module is installed at the front end of the spray gun frame and is used to emit lasers to provide the driver with a vehicle position reference. The driver can drive the vehicle to a roughly suitable position by comparing the position of the laser with that of the old line, so that the equipment can capture the old line information more accurately and improve the accuracy of subsequent identification and operation.

[0006] The vision sensor module is installed at the front end of the spray gun frame. It uses a high-resolution, high-sensitivity vision sensor to collect road surface image information including old lines. It can adjust the angle to provide basic data for subsequent image processing and recognition.

[0007] The boom position monitoring module is installed inside the telescopic boom. It uses a high-precision position sensor to monitor the actual position of the boom and compares it with the position expected by the calculation and control module. By providing real-time feedback on the boom position information, it determines whether the boom position deviation is within the allowable range. If it exceeds the allowable range, it adjusts the boom position in time to ensure that the spray gun can always accurately carry out the spraying operation along the old line.

[0008] The human-machine interface display is installed in the driver's cab and connected to the control module. It displays the system's operating status, parameter settings, fault information, and operation prompts. Drivers and operators can operate the system via the touchscreen, such as adjusting system parameters, viewing historical data, and starting or pausing certain functions. This facilitates convenient human-machine interaction, improves operational convenience and flexibility, and helps operators better understand the system's operation, enabling timely maintenance and adjustments.

[0009] The audible and visual alarm module is installed in the cab. When the system malfunctions, such as failure to identify the old line, the boom adjustment exceeding the maximum stroke, or abnormal spray gun status, it will promptly issue an audible and visual alarm to remind the driver and operators to take appropriate action, ensuring the safety and stability of the construction process.

[0010] The spray gun and status monitoring module monitor the working status of the spray gun in real time, including the spray gun pressure, paint flow rate, and whether the nozzle is clogged. It collects relevant data through pressure sensors, flow sensors, and other devices, and compares it with preset normal operating parameter ranges. If any abnormality is detected, an alarm is immediately issued and corresponding pause or adjustment measures are taken to ensure the stability and consistency of the spraying quality.

[0011] The glass bead spreading module is installed on the spray gun holder, behind the spray gun. After the spray gun finishes spraying the markings, the module can evenly spread reflective glass beads on the newly sprayed markings according to preset parameters and control logic, thereby improving the reflectivity of the markings and enhancing the safety of driving at night.

[0012] The control module is installed on the vehicle and includes: image preprocessing function, old line recognition function, calculation control function, spray gun status monitoring function, and calculation control function.

[0013] Image preprocessing function: The image acquired by the vision sensor is converted to grayscale, reducing the amount of data while highlighting the contour information of the image; advanced noise reduction algorithm is used to remove noise interference in the image to ensure image clarity; image enhancement technology is used to improve the contrast between the old line and the background, making the features of the old line more obvious, which is convenient for subsequent feature extraction and recognition operations.

[0014] Old road marking recognition function: Extracts key information such as geometric and texture features of old road markings from pre-processed images and performs matching operations with pre-stored old road marking templates to determine the location and direction of the old road markings. This module adopts optimized feature extraction algorithms and efficient matching algorithms, enabling it to quickly and accurately identify old road markings in complex road environments. Even if the old road markings have a certain degree of wear, fading, or partial occlusion, it can still strive to ensure a high success rate of recognition.

[0015] Calculation and control function: Based on the old line position determined by the old line identification module and the actual position of the current boom and spray gun, the extension and retraction amount of the boom telescopic drive cylinder and the adjustment amount of the spray gun frame height control drive cylinder are calculated through a precise mathematical model to achieve accurate following of the spray gun to the old line; at the same time, this module is also responsible for the logical control and coordination of the entire system to ensure the orderly operation of each module.

[0016] An automatic lane marking following control method based on old line recognition includes the following steps: 1. Startup and Initialization: After system startup, the system first performs initialization operations on each device, including calibrating each sensor, initializing controller parameters, and resetting each actuator, ensuring the entire system is in normal working condition and ready for subsequent work processes. Simultaneously, the human-machine interface display starts and shows system initialization completion information and a welcome screen, prompting operators to begin work.

[0017] 2. Laser-Assisted Positioning: The laser-assisted positioning module emits a laser, and the driver guides the vehicle to a roughly suitable position based on the laser indication. This allows the vision sensor to better capture the image of the road, initially improving the system's starting accuracy. At this time, the human-machine interface display shows the relative relationship between the vehicle and the laser-indicated position, as well as the recommended fine-tuning direction and distance based on the laser positioning, helping the driver to more accurately position the vehicle in the appropriate location.

[0018] 3. Image Acquisition and Preprocessing: After the visual sensor acquires road surface images, the image preprocessing module performs grayscale conversion, noise reduction, and enhancement to optimize image quality, highlight old road features, and provide a good data foundation for old road identification. During this process, the human-machine interface display shows the real-time image acquisition process (appropriately processed for operator viewing), as well as the progress of image preprocessing and related parameters, such as grayscale algorithm and noise reduction level, allowing operators to understand the internal workings of the system.

[0019] 4. Old Line Identification and Judgment: The old line identification module performs feature extraction and template matching on the preprocessed image to determine whether the old line identification is successful. If the identification is successful, it proceeds to the step of calculating the adjustment amount of the boom and spray gun positions; if the identification fails, an audible and visual alarm is triggered, indicating that the old line identification has failed, and a re-identification attempt is made. After re-identification, the module again determines whether it is successful. If successful, it proceeds to the step of calculating the adjustment amount; if it still fails, it prompts for manual intervention. After the manual intervention is completed, it returns to the step of image acquisition by the vision sensor.

[0020] 5. Position Adjustment Calculation and Judgment: The calculation and control module calculates the adjustment amount of the boom telescopic drive cylinder and the spray gun frame height control drive cylinder based on the old line position and the current equipment position, and judges whether the boom adjustment amount exceeds the maximum stroke; if it exceeds, an audible and visual alarm is triggered to remind the driver to wait for processing, and the judgment is made again after processing is completed; if it does not exceed, the process of adjusting the boom and spray gun positions is initiated.

[0021] 6. Boom and spray gun position adjustment: Based on the calculated adjustment amount, control the boom telescopic drive cylinder and the spray gun frame height control drive cylinder to precisely adjust the position of the boom and spray gun so that they are aligned with the old line, preparing for subsequent spraying operations.

[0022] 7. Spray Gun Status Monitoring and Judgment: The spray gun status monitoring module checks the pressure, flow rate, and nozzle blockage of the spray gun system to determine if the spray gun status is normal. If normal, it proceeds to the boom position monitoring stage; if abnormal, it issues an alarm and suspends operation, awaiting handling. After handling is completed, the spray gun status is judged again.

[0023] 8. Boom Position Monitoring and Adjustment: The boom position monitoring module monitors the actual boom position and compares it with the expected position to determine if the boom position deviation is within the allowable range. If it is within the allowable range, the marking line is sprayed; if it is not within the allowable range, the boom position is adjusted to the allowable range, and then the deviation is checked again.

[0024] 9. Spraying the markings: With the boom and spray gun in the correct positions and the spray gun in normal condition, the spray gun is used to spray the old lines according to the preset spraying parameters to ensure the quality and accuracy of the markings.

[0025] 10. Spreading glass beads: After the spray gun finishes spraying the markings, the glass bead spreading module evenly spreads reflective glass beads on the newly sprayed markings to improve the reflectivity of the markings.

[0026] The advantages of this invention are: Improved construction accuracy and efficiency: Through precise old line identification, intelligent position calculation and automatic control, the spray gun can closely follow the old line for spraying, which greatly improves the accuracy and efficiency of road marking construction and reduces errors and labor intensity caused by manual operation.

[0027] Enhanced system stability and adaptability: The system has multiple monitoring and anomaly handling mechanisms, such as retrying and manual intervention for old line identification failures, boom travel over-limit alarms, and spray gun status monitoring. It can maintain stable operation in complex construction environments and equipment failures, improving the system's adaptability and reliability to different working conditions.

[0028] Improving the quality and safety of road markings: The precise control and stable operation of the entire system help ensure the uniformity, continuity and clarity of the road markings, thereby improving the overall quality of the road markings. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the road marking vehicle of the present invention; Figure 2 This is a schematic diagram of the automatic marking mechanism of the present invention; Figure 3 This is a schematic diagram of the control system of the present invention; Figure 4 This is a schematic diagram of the first part of the control method of the present invention; Figure 5 This is a schematic diagram of the second part of the control method of the present invention; Figure 6 This is a schematic diagram of the third part of the control method of the present invention.

[0030] In the picture: 1. Spray gun holder folding boom; 2. Spray gun holder; 3. Paint tank; 4. Telescopic boom; 5. Control module; 6. Housing; 7. Human-machine interface display; 8. Audible and visual alarm module; 9. Chassis; 10. Vision sensor module; 201. Laser-assisted positioning module; 202. Spray gun and status monitoring module; 203. Glass bead spreading module; 204. Boom telescopic drive cylinder; 501. Encoder; 502. Tilt sensor; 503. Spray gun holder height control drive cylinder; 101. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0032] After system startup, each device performs self-checks and calibrations according to the preset initialization procedure. The calculation and control module zeroes all sensors within the system to ensure the accuracy of data acquisition; the boom telescopic drive cylinder and the spray gun frame height control drive cylinder return to their initial positions, ready to receive subsequent control commands; the vision sensor performs lens cleanliness detection and automatic focus adjustment to ensure the clarity and accuracy of image acquisition; the spray gun status monitoring module initializes and reads various parameters of the spray gun, recording initial pressure, flow rate, and other data to provide a benchmark for subsequent real-time monitoring.

[0033] Guided by the laser pointer emitted by the laser-assisted positioning module, the driver slowly maneuvers the vehicle towards the area where the old work line is located. When the vehicle approaches the appropriate position, the driver receives a feedback signal from the system via a display screen or indicator light inside the vehicle, indicating that the vehicle is in the optimal starting position for operation.

[0034] At this point, the vision sensor module begins to collect road surface image information, including the old line, at a preset frequency. The collected image data is transmitted in real time to the image preprocessing module through a high-speed data transmission line.

[0035] The image preprocessing module performs a series of optimization processes on the input image:

[0036] The first step is grayscale conversion, which transforms the color image into a grayscale image, reducing the amount of data while highlighting the image's contour features. During grayscale conversion, advanced algorithms such as weighted averaging are used to obtain a clearer grayscale image. The second step is to use an adaptive median filtering algorithm to remove noise interference from the image. This algorithm can automatically adjust the size and shape of the filtering window according to the local features of the image, effectively removing noise while preserving the edge details of the image. The third step is to improve the contrast between the old lines and the background by using image enhancement techniques such as histogram equalization, making the features of the old lines more obvious and facilitating subsequent feature extraction and recognition operations.

[0037] The pre-processed image data is quickly transmitted to the old line recognition module.

[0038] The old line recognition module uses a deep learning-based target detection algorithm combined with traditional image processing techniques to extract old line features and match templates from the preprocessed image.

[0039] First, a convolutional neural network is used to automatically learn and extract line features in the image. The network structure is trained and optimized with a large amount of old line sample data, which can accurately identify key information such as the geometric shape, texture features and color features of old lines.

[0040] Then, the extracted features are matched with a pre-stored library of old line templates. The library contains various types of old line templates with different degrees of wear. The location and direction of the old line are determined by feature similarity calculation.

[0041] If the old line identification module successfully identifies the old line within a certain time, it transmits the old line's location and direction information to the computing control module. If identification fails, the audible and visual alarm module is immediately triggered to issue an audible and visual alarm, alerting the operator that there is a problem with the old line identification. At the same time, the system automatically starts a re-identification program, re-processing the image according to the preset number of retries.

[0042] During the re-identification process, the system automatically adjusts the image preprocessing parameters and the threshold of the old line recognition algorithm to adapt to possible environmental changes or complex old lines. If the old line cannot be successfully identified after retries, the system prompts for manual intervention. Operators can view image data and system logs through the vehicle terminal to determine the cause of the problem and take appropriate measures, such as manually adjusting the vehicle position, cleaning the vision sensor lens, or performing simple preprocessing on the old line (such as removing debris covering the old line). After manual processing is completed, the system returns to the vision sensor image acquisition step and restarts the entire recognition process.

[0043] After receiving the position and direction information of the old line, the calculation and control module, combined with the actual position information of the boom and spray gun (provided in real time by the boom position monitoring module and the spray gun status monitoring module), calculates the extension and retraction amount of the boom telescopic drive cylinder and the adjustment amount of the spray gun frame height control drive cylinder through a pre-established precise mathematical model.

[0044] After calculating the adjustment amount, the calculation control module first determines whether the boom adjustment amount exceeds the boom's maximum stroke. If it does, the audible and visual alarm module is immediately triggered, and detailed error information is displayed on the vehicle's screen, including the excessive stroke, possible causes, and suggested corrective measures. This alerts the driver to take appropriate action, such as adjusting the vehicle position or pausing operations, and reassessing and adjusting the operating parameters. After the driver has taken action, feedback is sent to the system via the user interface, and the system again determines whether the boom adjustment amount has returned to the normal range. If it has not exceeded the maximum stroke, the calculation control module sends control signals to the boom telescopic drive cylinder and the spray gun frame height control drive cylinder, controlling them to operate according to the calculated adjustment amount, precisely adjusting the position of the boom and spray gun.

[0045] The boom telescopic drive cylinder and the spray gun holder height control drive cylinder employ a high-precision electric drive system, enabling rapid and accurate response to control signals and achieving precise position adjustment of the boom and spray gun. During adjustment, the boom position monitoring module and the spray gun status monitoring module monitor the actual positions of the boom and spray gun in real time and feed the position information back to the calculation control module. The calculation control module monitors and corrects the adjustment process in real time based on the feedback information, ensuring that the boom and spray gun accurately reach the expected position.

[0046] Once the boom and spray gun positions are adjusted, the spray gun status monitoring module begins real-time monitoring of the spray gun's operating status. This module collects data such as spray gun pressure and paint flow rate using devices like pressure sensors and flow sensors.

[0047] The nozzle clogging detection device determines nozzle clogging by detecting parameters such as pressure changes and paint spray uniformity at the nozzle. The collected data is compared with preset normal operating parameter ranges. If the spray gun is functioning normally, the system enters the boom position monitoring phase. If abnormal spray gun pressure, insufficient flow, or nozzle clogging is detected, the spray gun status monitoring module immediately issues an alarm and suspends spray gun operation, while simultaneously transmitting the abnormal information to the computing control module and the audible and visual alarm module. Upon receiving the alarm, the operator inspects and maintains the spray gun, such as clearing nozzle blockages and checking the paint supply system. After processing, the operator confirms through the user interface that the spray gun has returned to normal, and the system restarts the spray gun status monitoring program to determine if the spray gun is functioning normally.

[0048] When the spray gun is functioning normally, the boom position monitoring module continuously monitors the actual position of the boom and compares it with the expected position predicted by the calculation and control module. The boom position monitoring module uses a high-precision encoder and tilt sensor to acquire real-time position information of the boom in the left-right and up-down directions. By comparing the actual position with the expected position, it determines whether the boom position deviation is within the allowable range. If the deviation is within the allowable range, the calculation and control module sends a spraying command to the spray gun, which then performs the spraying operation on the old production line according to the preset spraying parameters. During the spraying process, the spray gun status monitoring module continues to monitor the working status of the spray gun in real time to ensure the stability and consistency of the spraying quality. If the boom position deviation exceeds the allowable range, the calculation and control module calculates the adjustment amount based on the magnitude of the deviation and sends an adjustment command to the boom telescopic drive cylinder to adjust the boom position to the allowable range. After adjustment, the boom position deviation is judged again until the deviation meets the requirements.

[0049] Throughout the construction process, the glass bead spreading module remains in standby mode. When the spray gun begins spraying the markings, the calculation and control module sends a trigger signal to the glass bead spreading module. Based on preset spreading parameters, such as the amount of glass beads spread, the spreading range, and the spreading speed, the glass bead spreading module controls the spreading device to evenly spread reflective glass beads onto the newly sprayed markings. The glass bead spreading module is equipped with a glass bead level monitoring device. When the glass bead level is insufficient, it promptly alerts the operator to replenish the glass beads, ensuring the continuity and stability of the spreading operation.

[0050] Through the above detailed implementation methods, the automatic road marking following control system of the present invention can efficiently, accurately and stably complete the road marking spraying operation based on old line recognition in various complex construction environments, significantly improving the quality and efficiency of road marking construction, reducing manual labor intensity and construction costs, and enhancing the safety and durability of road markings.

Claims

1. An automatic line following control system based on old line recognition, characterized by, include: Vision sensor module, boom position monitoring module, audible and visual alarm module, spray gun and status monitoring module, glass bead spreading module, control module, human-machine interface display; The controller, mounted on the vehicle, includes image preprocessing, old lane marking recognition, and computational control functions. The vision sensor module, mounted at the front of the spray gun mount, collects road surface images containing old lane markings. The boom position monitoring module, mounted on the boom, monitors the actual boom position. The audible and visual alarm module, mounted in the cab, issues audible and visual alarms when the system fails to recognize old lane markings, exceeds the maximum travel limit for boom adjustment, or experiences abnormal spray gun status. The spray gun and status monitoring module collects data from pressure sensors, flow sensors, and other devices to monitor the spray gun pressure, paint flow rate, and nozzle blockage in real time. The glass bead spreading module, mounted on the spray gun mount and located behind the spray gun, evenly spreads reflective glass beads onto the new marking line according to preset parameters and control logic after the marking is applied. The human-machine interface display, mounted in the cab and connected to the control module, displays the system's operating status, parameter settings, fault information, and operation prompts.

2. The automatic string following control system based on old line identification according to claim 1, characterized in that, It also includes a laser-assisted positioning module, installed at the front of the spray gun holder, which emits lasers to provide the driver with a reference for the vehicle's position.

3. The old line identification based automatic lane following control system of claim 1, wherein, The position sensors used in the boom position monitoring module include encoders and tilt sensors.

4. The old line identification based automatic lane following control system of claim 1, wherein, The nozzle clogging detection device in the spray gun and status monitoring module determines whether the nozzle is clogged by detecting pressure changes at the nozzle and the uniformity of paint spraying.

5. An automatic line following control method based on old line recognition, characterized by, Includes the following steps: I. Startup and Initialization: After the system starts up, each device performs initialization operations, including sensor calibration, controller parameter initialization, and actuator reset. At the same time, the human-machine interface display starts up and displays system initialization completion information and a welcome screen. II. Laser-assisted positioning: The laser-assisted positioning module emits a laser, and the driver drives the vehicle to a roughly suitable position according to the laser indication. The human-machine interface display shows the relative relationship between the vehicle and the laser indication position, as well as the vehicle's fine-tuning direction and distance. III. Image Acquisition and Preprocessing: After the visual sensor acquires road surface images, the image preprocessing module performs grayscale conversion, noise reduction, and enhancement processing on them. The human-machine interface display shows the real-time image acquisition, preprocessing progress, and relevant parameters. IV. Old Line Identification and Judgment: The old line identification module performs feature extraction and template matching on the pre-processed image. If the identification is successful, it enters the stage of calculating the adjustment amount of the boom and spray gun positions. If it fails, it triggers an audible and visual alarm and attempts to re-identify. After re-identification, it judges again. If it still fails, it prompts for manual intervention. After manual intervention is completed, it returns to the image acquisition step. The human-machine interaction display shows the old line identification results, feature extraction and matching progress, failure reasons and solutions in real time. V. Position Adjustment Calculation and Judgment: The calculation and control module calculates the adjustment amount of the boom telescopic drive cylinder and the spray gun frame height control drive cylinder based on the old line position and the current equipment position, and judges whether the boom adjustment amount exceeds the maximum stroke. If it exceeds the maximum stroke, an audible and visual alarm is triggered to remind the driver. After the process is completed, the judgment is made again. If it does not exceed the maximum stroke, the module enters the stage of adjusting the position of the boom and the spray gun. The human-machine interface display shows the calculated adjustment amount, the current position of the boom and the spray gun, and the maximum stroke limit, etc. VI. Boom and spray gun position adjustment: Based on the calculated adjustment amount, control the boom telescopic drive cylinder and the spray gun frame height control drive cylinder to precisely adjust the position of the boom and spray gun. VII. Spray Gun Status Monitoring and Judgment: The spray gun status monitoring module checks the pressure, flow rate and nozzle blockage of the spray gun system. If normal, it enters the boom position monitoring stage. If abnormal, it issues an alarm and suspends operation. After the problem is resolved, the spray gun status is judged again.

8. Boom position monitoring and adjustment: The boom position monitoring module monitors the actual position of the boom and compares it with the expected position. If the deviation is within the allowable range, the spray gun is used to spray markings. If it is not within the allowable range, the boom position is adjusted to the allowable range. Then the deviation is judged again to see if it is within the allowable range. The human-machine interface display continuously displays the actual position coordinates, expected position coordinates and deviation value of the boom.

9. Spraying markings with a spray gun: When the boom and spray gun are in the correct position and the spray gun is in normal condition, the spray gun will spray the old line according to the preset spraying parameters. The human-machine interface display shows the spraying progress, the amount of paint remaining and the real-time working parameters of the spray gun.

10. Spreading glass beads: After the spray gun completes the marking, the glass bead spreading module evenly spreads reflective glass beads on the new marking line. The human-machine interface display shows information such as the amount of glass beads spread, the spreading speed, and the remaining amount of glass beads.

6. The old line identification based automatic lane following control method according to claim 5, wherein, If the old line identification module fails to identify the old line within a certain period of time, it is determined to be an identification failure, and the number of retries for re-identification is a preset value.

7. The old line identification based automatic lane following control method of claim 5, wherein, The mathematical model used by the calculation and control module to calculate the adjustment amount of the boom telescopic drive cylinder and the spray gun frame height control drive cylinder takes into account factors such as vehicle speed, road surface smoothness, and changes in the curvature of the old road.

Images