A method and system for flow control in automotive parts painting lines

Abstract

This invention discloses a flow control method and system for automotive parts painting lines, relating to the field of flow control in automotive parts painting lines, used to improve painting quality and production efficiency. The method includes: before painting, evaluating the electrical connection status of the workpiece hanger to obtain electrical connection status information; the electrical connection status information includes the electrical loop resistance between the workpiece hanger and the conveyor chain ground wire; the workpiece hanger is used to fix the automotive parts to be painted; adjusting the initial electrostatic voltage and initial paint flow rate based on the electrical connection status information; during painting, monitoring the current flowing through the workpiece grounding loop to obtain the real-time deposition current; dynamically adjusting the electrostatic voltage and paint flow rate based on the deviation between the real-time deposition current and the target deposition current; the adjustment priority of the electrostatic voltage is greater than the adjustment priority of the paint flow rate.

Description

Technical Field

[0001] This invention relates to the field of flow control in automotive parts painting lines, and more particularly to a method and system for flow control in automotive parts painting lines. Background Technology

[0002] In the automotive manufacturing industry, the painting process for automotive parts is a crucial step in determining the final appearance quality and corrosion resistance of the product. Painting lines typically require precise control of paint flow to ensure uniformity and thickness of the paint film. During the painting process, workpieces are secured by specialized hangers and fed into the painting area by a conveyor chain. To ensure the efficiency of electrostatic spraying, electrical contact between the hangers and the workpiece, as well as between the hangers and the conveyor chain, is essential.

[0003] However, during prolonged production operations, the contact points of the hangers may gradually deteriorate due to wear, paint accumulation, or dust adhesion from the environment. This slight increase in contact resistance leads to less than ideal grounding of the workpiece. When grounding is poor, the charge on the workpiece surface cannot be effectively discharged, the electrostatic field strength weakens, and the adsorption force of charged paint particles decreases. As a result, some paint that should have been deposited on the workpiece will be oversprayed due to insufficient electrostatic adsorption, ultimately depositing on the spray booth walls or waste collection tank instead of the workpiece surface. In this case, although the flow meter shows accurate paint output, the actual paint transfer efficiency is reduced, resulting in a lower-than-expected effective paint film thickness on the workpiece.

[0004] Furthermore, to improve production line flexibility and efficiency, automotive factories often produce multiple models, materials, or geometries of parts on the same painting line. The painting system needs to frequently switch painting programs between different workpieces. This significantly increases the frequency of fixture grounding degradation. Existing flow control systems, whose core logic is to ensure a constant volumetric flow rate from the spray gun, cannot detect fluctuations in actual deposition efficiency caused by changes in system auxiliary conditions (such as fixture grounding status) during the interaction between the paint and the workpiece surface after spraying. Therefore, even with precise volumetric flow rate control, the final paint film quality may still exhibit batch-to-batch or intra-workpiece inconsistencies due to these "invisible" factors, leading to increased rework rates and impacting production efficiency and material utilization. Summary of the Invention

[0005] This invention provides a flow control method for automotive parts painting lines to improve painting quality and production efficiency.

[0006] In a first aspect, to solve the above-mentioned technical problems, the present invention provides a flow control method for an automotive parts painting line, comprising: before painting, evaluating the electrical connection status of the workpiece hanger to obtain electrical connection status information; the electrical connection status information includes the electrical loop resistance between the workpiece hanger and the ground wire of the conveyor chain; the workpiece hanger is used to fix the automotive parts to be painted; adjusting the initial electrostatic voltage and initial paint flow rate of the painting according to the electrical connection status information; during the painting process, monitoring the current flowing through the workpiece grounding loop to obtain the real-time deposition current; dynamically adjusting the electrostatic voltage and paint flow rate of the painting according to the deviation between the real-time deposition current and the target deposition current; the adjustment priority of the electrostatic voltage is greater than the adjustment priority of the paint flow rate.

[0007] Optionally, the electrostatic voltage and paint flow rate of the spraying process are dynamically adjusted based on the deviation between the real-time deposition current and the target deposition current. This includes: acquiring environmental parameters of the spraying area and the current paint type information; determining an adjustment strategy for the spraying parameters based on the environmental parameters and paint type information; and performing dynamic adjustments based on the deviation between the real-time deposition current and the target deposition current. Specifically, when the adjustment strategy indicates that environmental conditions are unfavorable for electrostatic adsorption, the adjustment priority of the paint flow rate is greater than that of the electrostatic voltage; when the adjustment strategy indicates that environmental conditions are favorable for electrostatic adsorption, the adjustment priority of the electrostatic voltage is greater than that of the paint flow rate.

[0008] Optionally, based on environmental parameters and coating type information, a spraying parameter adjustment strategy is determined, including: acquiring the rate of change of environmental parameters; determining whether the real-time deposition current has not recovered to the target deposition current range after electrostatic voltage adjustment; when the rate of change of environmental parameters is greater than or equal to a preset threshold, or when the real-time deposition current has not recovered to the target deposition current range after electrostatic voltage adjustment, determining the spraying parameter adjustment strategy to indicate that environmental conditions are unfavorable for electrostatic adsorption; when the rate of change of environmental parameters is less than a preset threshold, and when the real-time deposition current recovers to the target deposition current range after electrostatic voltage adjustment, determining the spraying parameter adjustment strategy to indicate that environmental conditions are favorable for electrostatic adsorption.

[0009] Optionally, dynamic adjustments are performed based on the deviation between the real-time deposition current and the target deposition current, including: acquiring the rate of change of the deviation between the real-time deposition current and the target deposition current; updating the adjustment parameters of electrostatic voltage and coating flow rate based on the rate of change of the deviation; the adjustment parameters include adjustment step size and adjustment frequency; and adjusting the electrostatic voltage and coating flow rate based on the deviation between the real-time deposition current and the target deposition current, and in conjunction with the updated adjustment parameters.

[0010] Optionally, the electrostatic voltage and paint flow rate of the spraying are dynamically adjusted based on the deviation between the real-time deposition current and the target deposition current. This includes: acquiring information on the type of paint being sprayed and the ambient temperature of the spraying area; determining the dominant parameters of electrostatic voltage and paint flow rate on the paint deposition efficiency under the current operating conditions based on the paint type information and ambient temperature information; and dynamically adjusting the electrostatic voltage and paint flow rate of the spraying based on the deviation between the real-time deposition current and the target deposition current, as well as the dominant parameters. The adjustment priority of the dominant parameters is greater than that of the non-dominant parameters.

[0011] Optionally, based on coating type information and ambient temperature information, determine the dominant parameters of electrostatic voltage and coating flow rate on coating deposition efficiency under the current operating conditions. This includes: under the operating conditions indicated by the current coating type information and ambient temperature information, performing small-amplitude disturbances on electrostatic voltage and coating flow rate before or at the initial stage of spraying; monitoring the changes in real-time deposition current after electrostatic voltage disturbance and the changes in real-time deposition current after coating flow rate disturbance; comparing the changes in real-time deposition current caused by electrostatic voltage disturbance with the changes in real-time deposition current caused by coating flow rate disturbance; and determining the dominant parameters of electrostatic voltage and coating flow rate on coating deposition efficiency under the current operating conditions based on the comparison results.

[0012] Optionally, comparing the changes in real-time deposition current caused by electrostatic voltage disturbances with the changes in real-time deposition current caused by coating flow rate disturbances includes: applying multiple disturbances of different amplitudes to the electrostatic voltage and monitoring the changes in real-time deposition current after each disturbance to obtain the correspondence between the electrostatic voltage disturbances and the changes in real-time deposition current; applying multiple disturbances of different amplitudes to the coating flow rate and monitoring the changes in real-time deposition current after each disturbance to obtain the correspondence between the coating flow rate disturbances and the changes in real-time deposition current; calculating the unit disturbance impact of electrostatic voltage on real-time deposition current based on the correspondence between the electrostatic voltage disturbances and the changes in real-time deposition current; calculating the unit disturbance impact of coating flow rate on real-time deposition current based on the correspondence between the coating flow rate disturbances and the changes in real-time deposition current; and comparing the unit disturbance impact of electrostatic voltage with the unit disturbance impact of coating flow rate.

[0013] Optionally, monitoring the real-time deposition current change after each disturbance includes: acquiring the real-time current signal; performing digital filtering on the real-time current signal; and performing time averaging on the digitally filtered real-time current signal to obtain the real-time deposition current change value.

[0014] Optionally, based on the electrical connection status information, the initial electrostatic voltage and initial paint flow rate of the spraying are adjusted, including: increasing the initial electrostatic voltage of the spraying and decreasing the initial paint flow rate when the electrical circuit resistance is greater than a preset resistance value; and controlling the initial electrostatic voltage and initial paint flow rate of the spraying to remain unchanged when the electrical circuit resistance is less than or equal to a preset resistance value.

[0015] Secondly, the present invention provides a flow control system for an automotive parts painting line, the system comprising:

[0016] The status assessment module is used to assess the electrical connection status of the workpiece hanger before spraying and obtain electrical connection status information. The electrical connection status information includes the electrical loop resistance between the workpiece hanger and the ground wire of the conveyor chain. The workpiece hanger is used to fix the automotive parts to be sprayed.

[0017] The initial parameter adjustment module is used to adjust the initial electrostatic voltage and initial paint flow rate of the spraying process based on the electrical connection status information.

[0018] The deposition current monitoring module is used to monitor the current flowing through the workpiece grounding circuit during the spraying process to obtain the real-time deposition current.

[0019] The dynamic parameter adjustment module is used to dynamically adjust the electrostatic voltage and paint flow rate of the spraying process based on the deviation between the real-time deposition current and the target deposition current; the adjustment priority of the electrostatic voltage is higher than that of the paint flow rate.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This application discloses a flow control method for automotive parts painting lines. By assessing the electrical connection status of the workpiece fixture before painting and adjusting the initial electrostatic voltage and paint flow rate accordingly, and by monitoring the current flowing through the workpiece grounding circuit in real time during painting and dynamically adjusting the electrostatic voltage and paint flow rate based on its deviation from the target deposition current, this method effectively solves the problems of reduced paint deposition efficiency, unstable paint film quality, and material waste caused by poor fixture grounding in existing technologies. Specifically, by introducing an electrical connection status assessment, this application can identify potential grounding problems in advance and compensate for initial parameters, avoiding quality defects in the early stages of painting. Simultaneously, by monitoring the deposition current in real time and dynamically adjusting painting parameters, this application can perceive the actual deposition effect of the paint on the workpiece surface in real time and perform precise feedback control based on deviations, ensuring effective paint deposition throughout the painting process and maintaining stable paint film quality and thickness even under fluctuating fixture grounding status or mixed production modes. Compared to traditional methods that only control the volumetric flow rate of the spray gun, this application can fundamentally improve the transfer efficiency and utilization rate of the coating, reduce overspray, lower production costs, and significantly improve product consistency and pass rate, thereby overcoming the impact of "invisible" factors on coating quality in the prior art. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a flow control method for an automotive parts painting line provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of another method for controlling the flow rate of an automotive parts painting line provided in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of a flow control system for an automotive parts painting line provided in an embodiment of the present invention. Detailed Implementation

[0025] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0026] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] The following specific embodiments will provide a detailed description and explanation of a flow control method for an automotive parts painting line provided in this application.

[0028] Reference Figure 1 This invention provides a method for flow control in an automotive parts painting line, comprising the following steps:

[0029] S1. Before spraying, assess the electrical connection status of the workpiece hanger to obtain electrical connection status information.

[0030] The electrical connection status information includes the electrical loop resistance between the workpiece hanger and the conveyor chain ground wire. This resistance value directly reflects the quality of the grounding effect. A smaller resistance value indicates a better electrical connection and a more ideal grounding effect; conversely, a larger resistance value indicates a problem with the electrical connection and a poorer grounding effect.

[0031] Among them, the workpiece hanger is used to fix the automotive parts to be painted.

[0032] In electrostatic spraying, the conveyor chain ground wire refers to the wire or conductive structure connected to the conveyor chain in the spraying production line and providing a grounding path. During electrostatic spraying, the workpiece forms an electrical circuit with the conveyor chain ground wire via a hanger, allowing the charge accumulated on the workpiece surface during spraying to be effectively discharged, thus ensuring the electrostatic adsorption effect.

[0033] As one possible implementation, the system can use a resistance meter to directly measure the resistance between the workpiece hanger and the ground wire of the conveyor chain to obtain electrical connection status information.

[0034] In practice, the two probes of the resistance measuring instrument can be contacted with the conductive part of the workpiece fixture and the ground wire of the conveyor chain, respectively, to obtain the electrical circuit resistance.

[0035] As another possible implementation, the system can set dedicated contact points on the hanger and use automated detection equipment to automatically contact these points and measure the resistance before the workpiece enters the spraying area to obtain electrical connection status information.

[0036] As another possible implementation, the system can also integrate a micro-sensor on the hanger to monitor its continuity with the ground wire in real time, and convert the continuity data into a resistance value to obtain electrical connection status information.

[0037] S2. Adjust the initial electrostatic voltage and initial paint flow rate for spraying based on the electrical connection status information.

[0038] The preset timeout threshold can be set as needed, for example, 500 milliseconds or 1 second, which represents the maximum allowed processing time for a single data packet or a batch of data packets.

[0039] As one possible implementation, the system can increase the initial electrostatic voltage of the spraying and reduce the initial flow rate of the paint when the electrical circuit resistance is greater than a preset resistance value.

[0040] When the electrical circuit resistance is less than or equal to the preset resistance value, the initial electrostatic voltage and initial paint flow rate of the control spray remain unchanged.

[0041] For example, on an automotive parts painting line, after repeated use, the surface of the workpiece hanger may accumulate a small amount of paint mist or dirt, causing the electrical circuit resistance between it and the conveyor chain ground wire to gradually increase. Before painting, the system first evaluates the electrical connection status of the workpiece hanger. If it detects an electrical circuit resistance of 500 ohms, while the preset resistance value is set to 300 ohms, the system determines that the current electrical circuit resistance is greater than the preset value. At this time, to ensure effective paint deposition, the system automatically increases the initial electrostatic voltage of the spraying from the usual 60kV to 70kV, while reducing the initial paint flow rate from the usual 300cc / min to 250cc / min.

[0042] In this way, even under less than ideal grounding conditions, sufficient electrostatic adsorption can be maintained, and waste or dripping caused by excessive coating can be avoided.

[0043] Conversely, if the system evaluates a newly replaced workpiece fixture with an electrical circuit resistance of 50 ohms, while the preset resistance is set to 100 ohms, the system determines that the current electrical circuit resistance is less than or equal to the preset resistance. Under these ideal grounding conditions, the system will maintain an initial electrostatic voltage of 60kV and an initial paint flow rate of 300cc / min for spraying without requiring additional adjustments, thus ensuring efficient spraying under optimal conditions.

[0044] Understandably, when the electrical circuit resistance is high, the system can proactively increase the electrostatic voltage to compensate for the loss of electrostatic adsorption force and reduce the paint flow rate to avoid over-spraying and waste, ensuring effective paint deposition even under unfavorable grounding conditions. Conversely, when the electrical circuit resistance is within the ideal range, the system maintains standard parameters, avoiding unnecessary adjustments, thereby ensuring the stability and efficiency of the spraying process. This adaptive adjustment mechanism based on electrical connection status allows the spraying line to better adapt to the actual conditions of the workpiece fixture, optimizing the initial spraying effect.

[0045] S3. During the spraying process, monitor the current flowing through the workpiece grounding circuit to obtain the real-time deposition current.

[0046] Real-time deposition current refers to the actual current flowing through the workpiece grounding circuit during the spraying process. This current is a key indicator for measuring the deposition efficiency of paint particles on the workpiece surface. When charged paint particles are deposited on the workpiece surface, the charge they carry is discharged through the workpiece grounding circuit, forming a current. Therefore, the magnitude of the real-time deposition current can indirectly reflect the actual amount of paint deposited.

[0047] As one possible implementation, a current sensor is connected in series in the workpiece grounding loop. The system can monitor the current flowing through the workpiece grounding loop by the current sensor to obtain the real-time deposited current.

[0048] In one example, the current sensor can be a Hall effect sensor, a shunt resistor, or a current transformer. When charged paint particles are deposited onto the workpiece surface, the charge they carry is discharged through the workpiece grounding loop, forming a current. This current signal is captured by the current sensor and converted into an electrical signal. This electrical signal is then transmitted to the control system, and after signal processing (such as filtering and amplification), the real-time deposition current value can be obtained. Monitoring the real-time deposition current is crucial for dynamically adjusting spraying parameters, as it directly reflects the actual deposition efficiency of the paint.

[0049] S4. Based on the deviation between the real-time deposition current and the target deposition current, dynamically adjust the electrostatic voltage and paint flow rate during spraying.

[0050] Among these, the adjustment priority of electrostatic voltage is higher than that of paint flow rate. The target deposition current refers to the preset deposition current value based on the ideal spraying effect and process requirements. During the spraying process, the real-time deposition current should be as close as possible to the target deposition current to ensure the uniformity and thickness of the paint film.

[0051] As one possible implementation, when the real-time deposition current is less than the target deposition current, the system will first attempt to increase the electrostatic voltage to enhance electrostatic attraction and promote coating deposition. If increasing the electrostatic voltage still fails to reach the target value, or if the electrostatic voltage has reached its upper limit, the system will then consider increasing the coating flow rate. Conversely, when the real-time deposition current is greater than the target deposition current, the system will first attempt to decrease the electrostatic voltage to reduce the amount of coating deposited. If decreasing the electrostatic voltage still results in a real-time deposition current higher than the target value, or if the electrostatic voltage has reached its lower limit, the system will then consider decreasing the coating flow rate.

[0052] This priority setting is based on the rapid response and direct impact of electrostatic voltage on coating deposition efficiency, enabling the real-time deposition current to be adjusted to the target range more quickly and accurately.

[0053] As another possible implementation, the system can dynamically adjust the electrostatic voltage and paint flow rate during spraying through the following steps:

[0054] S41. Obtain environmental parameters of the spraying area and the current paint type information.

[0055] Environmental parameters may include information such as temperature, humidity, air pressure, and air velocity. Information about the coating type may include physicochemical properties such as conductivity, dielectric constant, viscosity, solids content, and particle size distribution.

[0056] These environmental parameters directly affect the charged state of coating particles, the distribution of the electrostatic field, and the atomization and transport efficiency of the coating. For example, high humidity may increase the conductivity of air, reducing the electrostatic adsorption effect; while temperature may affect the viscosity and volatility of the coating. The type and properties of the current coating determine its response characteristics in the electrostatic field and its deposition behavior on the workpiece surface.

[0057] As one possible approach, operators can manually input the environmental parameters of the spraying area and the current paint type information into the system, and the system will then obtain the environmental parameters of the spraying area and the current paint type information.

[0058] S42. Determine the adjustment strategy for spraying parameters based on environmental parameters and coating type information.

[0059] The adjustment strategy aims to assess the effectiveness of electrostatic adsorption under current operating conditions. For example, if factors such as excessively high ambient humidity, poor paint conductivity, or excessively low temperature are deemed unfavorable for electrostatic adsorption, the adjustment strategy will indicate that the environmental conditions are unfavorable for electrostatic adsorption. Conversely, if environmental conditions are suitable and the paint properties are conducive to electrostatic adsorption, the adjustment strategy will indicate that the environmental conditions are favorable for electrostatic adsorption.

[0060] As one possible implementation, the system can acquire the rate of change of environmental parameters; and determine whether the real-time deposition current has not recovered to the target deposition current range after the electrostatic voltage adjustment; when the rate of change of environmental parameters is greater than or equal to a preset threshold, or when the real-time deposition current has not recovered to the target deposition current range after the electrostatic voltage adjustment, the system determines that the adjustment strategy of the spraying parameters is to indicate that the environmental conditions are not conducive to electrostatic adsorption.

[0061] When the rate of change of environmental parameters is less than the preset threshold, and when the real-time deposition current recovers to the target deposition current range after the electrostatic voltage adjustment, the adjustment strategy for the spraying parameters is determined to indicate that the environmental conditions are conducive to electrostatic adsorption.

[0062] The acquisition of the rate of change of environmental parameters refers to the system's continuous monitoring of environmental parameters within the spraying area, such as temperature, humidity, and air pressure, and the calculation of the magnitude or trend of these parameters' changes within a certain time window. For example, the rate of change can be calculated by comparing the current environmental parameter value with the average value of the previous moment or a period of time. The purpose is to capture dynamic changes in environmental conditions in order to adjust the spraying strategy more promptly.

[0063] The determination of whether the real-time deposition current has not recovered to the target deposition current range after electrostatic voltage adjustment refers to continuously monitoring the change in the real-time deposition current after the system adjusts the electrostatic voltage based on the deviation between the real-time deposition current and the target deposition current. If, after a period of adjustment, the real-time deposition current still has not reached or is close to the target deposition current range, it indicates that adjusting the electrostatic voltage alone may not be sufficient to solve the deposition efficiency problem. Its purpose is to evaluate the effectiveness of the electrostatic voltage adjustment and provide a basis for subsequent strategy decisions.

[0064] The preset threshold can be set based on historical data or expert experience to distinguish between stable and unstable environmental states.

[0065] S43. Perform dynamic adjustment based on the deviation between the real-time deposition current and the target deposition current.

[0066] Specifically, when the adjustment strategy indicates that the environmental conditions are unfavorable for electrostatic adsorption, the adjustment priority of the coating flow rate is greater than that of the electrostatic voltage; when the adjustment strategy indicates that the environmental conditions are favorable for electrostatic adsorption, the adjustment priority of the electrostatic voltage is greater than that of the coating flow rate.

[0067] In some preferred embodiments, a specific example is given below. Suppose that during the spraying process, the humidity in the spraying area suddenly increases, and the paint currently used is a humidity-sensitive type. The system first acquires information about the high humidity environmental parameters and the paint type. Based on a preset strategy or through real-time evaluation, the system determines that the current environmental conditions are unfavorable for electrostatic adsorption. At this point, even if there is a deviation between the real-time deposition current and the target deposition current, the system will prioritize adjusting the paint flow rate over adjusting the electrostatic voltage. This means that during dynamic adjustments, the system will prioritize or significantly adjust the paint flow rate to compensate for insufficient deposition caused by the decreased electrostatic adsorption efficiency, rather than blindly increasing the electrostatic voltage. For example, if the real-time deposition current is lower than the target value, the system will first increase the paint flow rate to ensure sufficient paint reaches the workpiece surface.

[0068] Conversely, in another example, assuming the ambient temperature and humidity of the spraying area are within ideal ranges, and the paint type also has good electrostatic adsorption properties, the system, after acquiring these environmental parameters and paint type information, will determine that the current environmental conditions are favorable for electrostatic adsorption. In this case, the adjustment priority of the electrostatic voltage will remain higher than the adjustment priority of the paint flow rate. When there is a deviation between the real-time deposition current and the target deposition current, the system will prioritize adjusting the electrostatic voltage, because under favorable electrostatic adsorption conditions, a small adjustment of the electrostatic voltage can quickly and effectively affect the deposition current, thereby achieving more precise flow control. For example, if the real-time deposition current is slightly higher than the target value, the system will slightly reduce the electrostatic voltage to precisely adjust the deposition current back to the target range.

[0069] Through the above technical solution, this application can significantly improve the flow control accuracy and adaptability of automotive parts painting lines. Under varying environmental conditions and different paint types, the system can intelligently adjust the control priority of electrostatic voltage and paint flow rate to ensure that the paint is always deposited onto the workpiece surface with optimal efficiency. This not only helps improve painting quality and reduce paint waste, but also increases production efficiency and reduces operating costs. Compared with traditional fixed priority adjustment methods, the solution of this application can better cope with the complexity and uncertainty in actual production, thereby achieving more stable and efficient painting operations.

[0070] In one possible design, such as Figure 2 As shown, in order to perform dynamic adjustments based on the deviation between the real-time deposition current and the target deposition current, this application may further include the following steps:

[0071] S101. Obtain the rate of change of the deviation between the real-time deposition current and the target deposition current.

[0072] Among them, obtaining the rate of change of the deviation between the real-time deposition current and the target deposition current refers to continuously monitoring the deviation between the real-time deposition current and the target deposition current and calculating the trend of these deviation values ​​over time.

[0073] For example, the rate of change can be obtained by calculating the difference between the current deviation and the deviation at the previous moment, or by using more complex mathematical methods (such as difference estimation, derivative estimation, etc.). This rate of change reflects the speed and direction of the deposition current deviating from the target value.

[0074] S102. Update the adjustment parameters of electrostatic voltage and paint flow rate according to the rate of change of the deviation.

[0075] The adjustment parameters include adjusting the step size and adjusting the frequency.

[0076] As one possible approach, when the rate of change of the deviation is large, the system can increase the adjustment step size and / or increase the adjustment frequency to achieve a faster response; when the rate of change of the deviation is small, the system can decrease the adjustment step size and / or decrease the adjustment frequency to avoid over-adjustment and system oscillation, thereby improving the smoothness and accuracy of the adjustment.

[0077] S103. Based on the deviation between the real-time deposition current and the target deposition current, and in conjunction with the adjusted parameters, adjust the electrostatic voltage and coating flow rate.

[0078] As one possible implementation, the system can adjust the electrostatic voltage and coating flow rate with updated adjustment step size and frequency until the deviation between the real-time deposition current and the target deposition current is less than the deviation threshold.

[0079] The deviation threshold can be set as needed. For example, it can be 0.

[0080] In this way, the final adjustment of electrostatic voltage and paint flow rate not only takes into account the current magnitude of the deviation, but also the adjustment step size and frequency determined by the rate of change of the deviation. Therefore, the adjustment process becomes more intelligent and efficient, ensuring precise control of the spraying parameters.

[0081] In some preferred embodiments, a specific example is given below. Suppose that during the spraying process, a sudden change in workpiece shape or a momentary blockage in the spray gun causes a sudden and significant drop in the real-time deposition current, resulting in a large negative deviation from the target deposition current. At this time, the system not only detects a large deviation value but also detects that the rate of change of this deviation is also significantly negative (i.e., the current decreases rapidly). According to the solution of this application, the system immediately adjusts the adjustment parameters of the electrostatic voltage and paint flow rate based on this large rate of change of negative deviation. For example, it increases the adjustment step size of the electrostatic voltage and increases the adjustment frequency, while simultaneously adjusting the adjustment step size of the paint flow rate accordingly. Thus, the system can increase the electrostatic voltage and paint flow rate more quickly and significantly, thereby rapidly bringing the real-time deposition current back to the target range and avoiding prolonged insufficient deposition.

[0082] Conversely, if the deviation between the real-time deposition current and the target deposition current is small, and its rate of change is slow (e.g., slight current drift due to slow fluctuations in ambient temperature), the system will adjust to a smaller adjustment step size and a lower adjustment frequency based on the small rate of change of the deviation. In this case, the adjustment of electrostatic voltage and paint flow rate will be smoother and more precise, effectively avoiding system oscillations caused by over-adjustment, and ensuring the stability of the spraying process and the uniformity of coating quality.

[0083] However, in actual spraying processes, there are many types of coatings, and the ambient temperature of the spraying area may fluctuate. These factors can significantly affect the deposition efficiency of electrostatic spraying. If the dominant roles of electrostatic voltage and coating flow rate on coating deposition efficiency are not fully identified under specific coating types and ambient temperature conditions, the adjustment strategy may not be precise enough, making it difficult to achieve optimal coating deposition results and resource utilization.

[0084] In one possible design, in order to dynamically adjust the electrostatic voltage and paint flow rate during spraying based on the deviation between the real-time deposition current and the target deposition current, this application further includes the following steps:

[0085] S201. Obtain information on the type of paint being sprayed and the ambient temperature of the spraying area.

[0086] The coating type information can include the coating's viscosity, conductivity, dielectric constant, and other physicochemical properties. This information can be obtained through a pre-set database, reading from the markings on the coating packaging, or through real-time detection by sensors.

[0087] Ambient temperature information can be collected in real time using temperature sensors installed within the spraying area. This information collectively defines the current spraying conditions and is a key factor affecting paint deposition efficiency.

[0088] S202. Based on the coating type information and ambient temperature information, determine the dominant parameters of electrostatic voltage and coating flow rate on coating deposition efficiency under the current operating conditions.

[0089] The dominant effect parameter indicates which of the two—electrostatic voltage and paint flow rate—has a more significant or direct impact on the deposition effect of the paint under specific coating and temperature conditions. For example, some high-viscosity or low-conductivity coatings may be more sensitive to changes in electrostatic voltage, while others may respond more significantly to changes in paint flow rate at specific temperatures.

[0090] As one possible implementation, the system can slightly disturb the electrostatic voltage and paint flow rate at the beginning of spraying and monitor the real-time response change of the deposition current, and take the parameter with the largest response change as the dominant parameter.

[0091] As another possible implementation, the system can count the difference between the number of newly added data packets and the number of processed data packets in the pending log queue within a specific time interval, and determine the difference as the growth rate of the pending log queue.

[0092] S203. Based on the deviation between the real-time deposition current and the target deposition current, as well as the dominant parameters, dynamically adjust the electrostatic voltage and paint flow rate during spraying.

[0093] Among them, the adjustment priority of the dominant parameter is greater than that of the non-dominant parameter.

[0094] As one possible implementation, when the real-time deposition current deviates from the target value, the system will prioritize adjusting the parameter that has been determined as the "dominant parameter".

[0095] For example, if the electrostatic voltage is determined to be the dominant parameter, the electrostatic voltage will be adjusted preferentially or with larger steps and higher frequency during adjustment to quickly and effectively correct deviations in the deposition current.

[0096] In some preferred embodiments, a specific example is given below. Suppose that in a painting operation, the automotive parts to be painted require a special high-resistivity paint, and the ambient temperature of the painting area is high. Under these conditions, the system first acquires the type information of the paint (high resistivity) and the ambient temperature information (e.g., 30 degrees Celsius). Then, based on a preset empirical model or through small-amplitude perturbation tests (e.g., making minor adjustments to the electrostatic voltage and paint flow rate and observing changes in the real-time deposition current), the system determines that under this combination of high-resistivity paint and high temperature, the electrostatic voltage has a more significant impact on the charging and adsorption effects of the paint. Therefore, the electrostatic voltage is determined as the dominant parameter. During the painting process, if the deposition current monitoring module detects that the real-time deposition current is lower than the target deposition current, the dynamic parameter adjustment module will prioritize adjusting the electrostatic voltage, for example, increasing the electrostatic voltage in larger steps to rapidly increase the charge and adsorption force of the paint, thereby restoring the deposition current to the target range. Only when the adjustment effect of the electrostatic voltage is not significant or reaches its adjustment upper limit will adjusting the paint flow rate be considered as an auxiliary means. This dynamic adjustment strategy based on the dominant parameters ensures that the most effective control methods can be used to optimize the deposition efficiency of the coating under specific operating conditions.

[0097] Understandably, this prioritization ensures that the most effective control measures can be applied in a complex and ever-changing painting environment, thereby improving the speed and accuracy of adjustments.

[0098] However, this method of determination based on preset information or models may not be able to fully capture the complex dynamic changes and interactions during the spraying process. For example, when there are environmental factors that are not fully modeled or subtle changes in material properties, the pre-determined dominant parameters may not accurately reflect the real impact under actual working conditions, which may limit the accuracy and response speed of dynamic adjustments.

[0099] In one possible design, to determine the dominant parameters of electrostatic voltage and paint flow rate on paint deposition efficiency under current operating conditions, this application further includes the following steps:

[0100] S301. Under the operating conditions indicated by the current coating type information and ambient temperature information, the electrostatic voltage and coating flow rate are slightly disturbed before or at the beginning of spraying.

[0101] In particular, before the start of the spraying operation or in the initial stage of spraying, the electrostatic voltage and paint flow rate can be adjusted in a controlled and small-amplitude instantaneous manner, that is, a "small-amplitude disturbance" can be made.

[0102] This perturbation aims to detect the system's sensitivity to changes in these parameters without significantly affecting normal coating quality. For example, the electrostatic voltage can be briefly increased or decreased by a preset value, and the paint flow rate can be briefly increased or decreased by a preset value. These perturbations are transient to ensure their impact on the final coating effect is minimized, but sufficient to cause a measurable real-time change in the deposition current.

[0103] S302. Monitor the real-time changes in deposition current after electrostatic voltage disturbance and the real-time changes in deposition current after coating flow disturbance.

[0104] As one possible implementation, after performing the aforementioned small-amplitude perturbation, the system immediately monitors the change in real-time deposition current flowing through the workpiece grounding loop. For each perturbation of the electrostatic voltage, the resulting real-time deposition current response is recorded; similarly, for each perturbation of the coating flow rate, the resulting real-time deposition current response is also recorded. This monitoring aims to quantify the direct impact of each parameter change on coating deposition efficiency.

[0105] S303. Compare the changes in real-time deposition current caused by electrostatic voltage disturbance with the changes in real-time deposition current caused by coating flow disturbance.

[0106] As one possible implementation, the system can compare the changes in real-time deposition current caused by electrostatic voltage disturbances with the changes in real-time deposition current caused by coating flow disturbances, based on the magnitude of the change, the rate of change, or a combination of both.

[0107] For example, the change in real-time deposited current caused by a unit disturbance (such as a change in voltage per volt or a change in flow rate per milliliter per minute) can be calculated.

[0108] This comparison allows for a direct assessment of which parameter has a more significant impact on coating deposition efficiency under current operating conditions.

[0109] S304. Based on the comparison results, determine the dominant parameters of electrostatic voltage and coating flow rate on coating deposition efficiency under the current operating conditions.

[0110] In one example, if a disturbance in the electrostatic voltage leads to a larger or faster change in the real-time deposition current, the electrostatic voltage is determined to be the dominant effect parameter; conversely, if a disturbance in the coating flow rate leads to a larger or faster change in the real-time deposition current, the coating flow rate is determined to be the dominant effect parameter.

[0111] In some preferred embodiments, a specific example is given below. Assume that in a certain automotive parts painting operation, the current paint type is water-based, and the ambient temperature is 25 degrees Celsius. To determine the dominant parameters of electrostatic voltage and paint flow rate on paint deposition efficiency under the current conditions, the system can perform the following steps:

[0112] First, during the initial stage of spraying, the system slightly agitates the electrostatic voltage. For example, the electrostatic voltage is briefly increased by 500V from a preset value, and the change in real-time deposition current is monitored. Assume an increase of 10mA in the real-time deposition current is detected. Subsequently, the electrostatic voltage is restored to the preset value.

[0113] Next, the system slightly agitates the coating flow rate. For example, it briefly increases the coating flow rate by 5 ml / min from the preset value and monitors the change in real-time deposition current. Assume that the real-time deposition current increases by 3 mA.

[0114] Comparison revealed that the real-time deposition current change caused by electrostatic voltage disturbance (10mA) was significantly greater than that caused by paint flow rate disturbance (3mA). Based on this comparison, the system can determine that under the current conditions of water-based paint and 25 degrees Celsius, electrostatic voltage is the dominant parameter affecting paint deposition efficiency. Therefore, in subsequent dynamic adjustments, the adjustment priority of electrostatic voltage will be set higher than that of paint flow rate to ensure faster and more effective adjustment of the real-time deposition current to the target deposition current.

[0115] However, in actual implementation, simply comparing the absolute changes in real-time deposition current caused by disturbances may not accurately reflect the true sensitivity of electrostatic voltage and coating flow rate to deposition efficiency, especially when the disturbance amplitude is inconsistent or the system response has a nonlinear relationship, which may lead to an inaccurate judgment of the dominant parameters.

[0116] In this regard, this application further proposes the above-mentioned comparison of the changes in real-time deposition current caused by electrostatic voltage disturbance and the changes in real-time deposition current caused by coating flow disturbance, including:

[0117] S401. Perform multiple perturbations with different amplitudes on the electrostatic voltage and monitor the real-time deposition current change after each perturbation to obtain the correspondence between the electrostatic voltage perturbation and the real-time deposition current change.

[0118] Applying multiple perturbations of different amplitudes to the electrostatic voltage refers to making a series of planned, minute adjustments of varying magnitudes to the currently applied electrostatic voltage during the spraying process.

[0119] For example, based on the current voltage value, multiple preset voltage steps can be increased or decreased. After each disturbance, the system monitors and records the changes in the real-time deposition current flowing through the workpiece grounding loop. By collecting these real-time deposition current change data under different disturbance amplitudes, a correspondence between the disturbance amount of electrostatic voltage and the real-time deposition current change can be established. This correspondence can be represented as a set of data points, a functional relationship, or a lookup table.

[0120] As one possible implementation, the system can digitally filter the real-time current signal after acquiring it, and then perform time averaging on the digitally filtered real-time current signal to obtain the real-time deposition current change value.

[0121] Time averaging refers to sampling a signal within a certain time window and calculating its average value. For example, a moving average window can be set, and multiple sampling points within the window can be averaged to obtain a stable value representing the deposited current within that time period.

[0122] S402. Perform multiple perturbations with different amplitudes on the coating flow rate and monitor the change in real-time deposition current after each perturbation to obtain the correspondence between the perturbation of coating flow rate and the change in real-time deposition current.

[0123] Applying multiple perturbations of different magnitudes to the paint flow rate refers to making a series of small adjustments to the current paint flow rate and monitoring the real-time deposition current change after each perturbation, thereby obtaining the correspondence between the perturbation of the paint flow rate and the real-time deposition current change.

[0124] S403. Based on the correspondence between the disturbance of electrostatic voltage and the change of real-time deposition current, calculate the unit disturbance effect of electrostatic voltage on real-time deposition current.

[0125] The effect of a unit disturbance of electrostatic voltage on real-time deposition current can be understood as the change in real-time deposition current when the electrostatic voltage changes by one unit. It can be calculated by the correspondence between the disturbance of electrostatic voltage and the change of real-time deposition current, for example, by the slope or average rate of change of the fitted curve.

[0126] S404. Based on the correspondence between the disturbance of coating flow rate and the change of real-time deposition current, calculate the unit disturbance effect of coating flow rate on real-time deposition current.

[0127] The unit disturbance effect of coating flow rate on real-time deposition current refers to the change in real-time deposition current when the coating flow rate changes by one unit.

[0128] S405. Compare the unit disturbance effect of electrostatic voltage with the unit disturbance effect of paint flow rate.

[0129] For example, the system can compare the magnitudes of the two unit disturbance effects and determine the parameter with the largest unit disturbance effect as the dominant parameter for coating deposition efficiency under the current operating conditions.

[0130] In some preferred embodiments, a specific example is given below. Suppose that under a specific operating condition, to determine the dominant parameters of electrostatic voltage and coating flow rate, a series of perturbations can be applied to the electrostatic voltage, for example, increasing or decreasing it by 1kV, 2kV, and 3kV from a reference voltage, and recording the stable change in real-time deposition current after each perturbation. Using these data points, a curve showing the relationship between the change in electrostatic voltage and the change in real-time deposition current can be plotted, and the slope of this curve can be calculated, i.e., the unit perturbation effect of the electrostatic voltage on the real-time deposition current. Similarly, the coating flow rate can be perturbed, for example, increasing or decreasing it by 5ml / min, 10ml / min, and 15ml / min from a reference flow rate, and the stable change in real-time deposition current after each perturbation can be recorded. Likewise, the unit perturbation effect of the coating flow rate on the real-time deposition current can be calculated. Finally, by comparing the magnitudes of these two unit perturbation effects, it is possible to accurately determine which has a stronger dominant effect on coating deposition efficiency under the current operating condition: electrostatic voltage or coating flow rate.

[0131] The above technical solution enables a more accurate and reliable determination of the dominant parameters affecting coating deposition efficiency under current operating conditions, namely electrostatic voltage and coating flow rate. This precise determination helps avoid misjudgments caused by simple comparisons, allowing subsequent dynamic adjustment strategies to more effectively optimize the dominant parameters, significantly improving coating deposition efficiency and spraying quality, reducing coating waste, and enhancing production line stability.

[0132] like Figure 3 As shown in the figure, this embodiment of the invention also provides a flow control system for an automotive parts painting line. The system includes:

[0133] The status assessment module is used to assess the electrical connection status of the workpiece hanger before spraying and obtain electrical connection status information. The electrical connection status information includes the electrical loop resistance between the workpiece hanger and the ground wire of the conveyor chain. The workpiece hanger is used to fix the automotive parts to be sprayed.

[0134] The initial parameter adjustment module is used to adjust the initial electrostatic voltage and initial paint flow rate of the spraying process based on the electrical connection status information.

[0135] The deposition current monitoring module is used to monitor the current flowing through the workpiece grounding circuit during the spraying process to obtain the real-time deposition current.

[0136] The dynamic parameter adjustment module is used to dynamically adjust the electrostatic voltage and paint flow rate of the spraying process based on the deviation between the real-time deposition current and the target deposition current; the adjustment priority of the electrostatic voltage is higher than that of the paint flow rate.

[0137] For example, a computer program can be divided into one or more modules / units, one or more of which are stored in memory and executed by a processor to complete the present invention. One or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in a terminal device.

[0138] Terminal devices can be computing devices such as desktop computers, laptops, PDAs, and smart tablets. Terminal devices may include, but are not limited to, processors and memory. Those skilled in the art will understand that the above-described components are merely examples of terminal devices and do not constitute a limitation on the terminal device. The device may include more or fewer components than described above, or a combination of certain components, or different components. For example, a terminal device may also include input / output devices, network access devices, buses, etc.

[0139] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device through various interfaces and lines.

[0140] Memory can be used to store computer programs and / or modules. The processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory. Memory can mainly include a program storage area and a data storage area. The program storage area can store the operating system, application programs required for at least one function (such as sound playback function, image playback function, etc.), etc.; the data storage area can store data created based on the use of the mobile phone (such as audio data, phonebook, etc.). In addition, memory can include high-speed random access memory, and can also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, SmartMedia Card (SMC), Secure Digital (SD) card, Flash Card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0141] If the modules / units integrated into the terminal device are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or system capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0142] It should be noted that the system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the system embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0143] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention in detail. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A flow control method for an automotive parts painting line, characterized in that, Includes the following steps: Before spraying, the electrical connection status of the workpiece hanger is evaluated to obtain electrical connection status information; the electrical connection status information includes the electrical loop resistance between the workpiece hanger and the ground wire of the conveyor chain; the workpiece hanger is used to fix the automotive parts to be sprayed; Based on the electrical connection status information, adjust the initial electrostatic voltage and initial paint flow rate for spraying; During the spraying process, the current flowing through the workpiece grounding circuit is monitored to obtain the real-time deposition current; Based on the deviation between the real-time deposition current and the target deposition current, the electrostatic voltage and paint flow rate of the spraying are dynamically adjusted. The adjustment of electrostatic voltage has a higher priority than the adjustment of paint flow rate; The step of dynamically adjusting the electrostatic voltage and paint flow rate of the spraying based on the deviation between the real-time deposition current and the target deposition current includes: Obtain environmental parameters of the spraying area and information on the current paint type; Based on the environmental parameters and the coating type information, determine the adjustment strategy for the spraying parameters; Dynamic adjustments are performed based on the deviation between the real-time deposition current and the target deposition current; Specifically, when the adjustment strategy indicates that the environmental conditions are unfavorable for electrostatic adsorption, the adjustment priority of the coating flow rate is greater than the adjustment priority of the electrostatic voltage; when the adjustment strategy indicates that the environmental conditions are favorable for electrostatic adsorption, the adjustment priority of the electrostatic voltage is greater than the adjustment priority of the coating flow rate. The step of adjusting the initial electrostatic voltage and initial paint flow rate based on the electrical connection status information includes: When the resistance of the electrical circuit is greater than a preset resistance value, the initial electrostatic voltage of the spraying is increased and the initial flow rate of the coating is reduced. When the resistance of the electrical circuit is less than or equal to the preset resistance value, the initial electrostatic voltage and initial paint flow rate of the spraying are kept constant.

2. The method for flow control in an automotive parts painting line according to claim 1, characterized in that, The step of determining the adjustment strategy for spraying parameters based on the environmental parameters and the coating type information includes: Obtain the rate of change of the environmental parameters; Determine whether the real-time deposition current has not returned to the target deposition current range after the electrostatic voltage adjustment; When the rate of change of the environmental parameters is greater than or equal to the preset threshold, or when the real-time deposition current fails to recover to the target deposition current range after the electrostatic voltage is adjusted, the adjustment strategy for the spraying parameters is determined to indicate that the environmental conditions are unfavorable for electrostatic adsorption. When the rate of change of the environmental parameters is less than a preset threshold, and when the real-time deposition current recovers to the target deposition current range after the electrostatic voltage adjustment, the adjustment strategy for the spraying parameters is determined to indicate that the environmental conditions are conducive to electrostatic adsorption.

3. The method for flow control in an automotive parts painting line according to claim 1, characterized in that, The step of performing dynamic adjustment based on the deviation between the real-time deposition current and the target deposition current includes: The rate of change of the deviation between the real-time deposition current and the target deposition current is obtained; The adjustment parameters for the electrostatic voltage and paint flow rate are updated based on the rate of change of the deviation; the adjustment parameters include the adjustment step size and the adjustment frequency. Based on the deviation between the real-time deposition current and the target deposition current, and in conjunction with the updated adjustment parameters, the electrostatic voltage and coating flow rate are adjusted.

4. The method for flow control in an automotive parts painting line according to claim 1, characterized in that, The step of dynamically adjusting the electrostatic voltage and paint flow rate of the spraying based on the deviation between the real-time deposition current and the target deposition current includes: Obtain information on the type of paint being sprayed and the ambient temperature of the spraying area; Based on the coating type information and the ambient temperature information, determine the dominant parameters of electrostatic voltage and coating flow rate on coating deposition efficiency under the current operating conditions; Based on the deviation between the real-time deposition current and the target deposition current, and the dominant action parameter, the electrostatic voltage and paint flow rate of the spraying are dynamically adjusted; the adjustment priority of the dominant action parameter is greater than the adjustment priority of the non-dominant action parameter.

5. The method for flow control in an automotive parts painting line according to claim 4, characterized in that, The step of determining the dominant parameters of electrostatic voltage and paint flow rate on paint deposition efficiency under the current operating conditions based on the paint type information and the ambient temperature information includes: Under the conditions indicated by the current coating type and ambient temperature information, the electrostatic voltage and coating flow rate are slightly disturbed before or at the beginning of spraying. Monitor the real-time changes in deposition current after electrostatic voltage disturbance and the real-time changes in deposition current after coating flow disturbance; Compare the changes in real-time deposition current caused by the electrostatic voltage disturbance with the changes in real-time deposition current caused by the coating flow rate disturbance; Based on the comparison results, the dominant parameters for the coating deposition efficiency under the current operating conditions were determined to be electrostatic voltage and coating flow rate.

6. The method for flow control in an automotive parts painting line according to claim 5, characterized in that, The comparison of the real-time deposition current change caused by the electrostatic voltage disturbance with the real-time deposition current change caused by the coating flow rate disturbance includes: Multiple perturbations with different amplitudes were applied to the electrostatic voltage, and the changes in the real-time deposition current after each perturbation were monitored to obtain the correspondence between the perturbation of the electrostatic voltage and the changes in the real-time deposition current. Multiple perturbations with different amplitudes were applied to the coating flow rate, and the changes in real-time deposition current after each perturbation were monitored to obtain the correspondence between the perturbation of coating flow rate and the changes in real-time deposition current. Based on the correspondence between the disturbance of the electrostatic voltage and the change of the real-time deposition current, the unit disturbance effect of the electrostatic voltage on the real-time deposition current is calculated. Based on the correspondence between the disturbance of the coating flow rate and the change of real-time deposition current, the unit disturbance effect of the coating flow rate on the real-time deposition current is calculated. Compare the unit disturbance effect of the electrostatic voltage with the unit disturbance effect of the coating flow rate.

7. The method for flow control in an automotive parts painting line according to claim 6, characterized in that, The monitoring of changes in the real-time deposited current after each disturbance includes: Acquire real-time current signals; The real-time current signal is digitally filtered. The real-time current signal after digital filtering is averaged over time to obtain the real-time deposition current change value.

8. A flow control system for an automotive parts painting line, characterized in that, The system includes: The status assessment module is used to assess the electrical connection status of the workpiece hanger before spraying and obtain electrical connection status information; the electrical connection status information includes the electrical loop resistance between the workpiece hanger and the ground wire of the conveyor chain; the workpiece hanger is used to fix the automotive parts to be sprayed; The initial parameter adjustment module is used to adjust the initial electrostatic voltage and initial paint flow rate of the spraying process based on the electrical connection status information. It is also used to increase the initial electrostatic voltage of spraying and reduce the initial flow rate of paint when the resistance of the electrical circuit is greater than a preset resistance value. When the resistance of the electrical circuit is less than or equal to the preset resistance value, the initial electrostatic voltage and initial paint flow rate of the spraying are kept constant. The deposition current monitoring module is used to monitor the current flowing through the workpiece grounding circuit during the spraying process to obtain the real-time deposition current. The dynamic parameter adjustment module is used to dynamically adjust the electrostatic voltage and paint flow rate of the spraying based on the deviation between the real-time deposition current and the target deposition current; the adjustment priority of the electrostatic voltage is greater than the adjustment priority of the paint flow rate. It is also used to obtain environmental parameters of the spraying area and information on the type of the current coating. Based on the environmental parameters and the coating type information, determine the adjustment strategy for the spraying parameters; Dynamic adjustments are performed based on the deviation between the real-time deposition current and the target deposition current; Specifically, when the adjustment strategy indicates that the environmental conditions are unfavorable for electrostatic adsorption, the adjustment priority of the coating flow rate is greater than the adjustment priority of the electrostatic voltage; when the adjustment strategy indicates that the environmental conditions are favorable for electrostatic adsorption, the adjustment priority of the electrostatic voltage is greater than the adjustment priority of the coating flow rate.

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