A method and system for controlling the production process of a ceiling panel

Abstract

The application provides a ceiling panel production process control method and system, applied to the technical field of ceiling machines, through obtaining the first acting force and displacement parameters of the pressing mechanism in the contact detection stage, the first-order slope of the acting force and displacement curve and its change rate are monitored in real time. When the slope change rate reaches the mutation threshold, it is determined as a phase switching point, that is, the pressing mechanism is switched from eliminating mechanical clearance to workpiece deformation state. The second acting force and displacement parameters after the switching point are extracted, and the stiffness slope of the panel to be pressed is calculated. According to the deviation of the stiffness slope and the standard slope, the displacement threshold of the position control switching to the torque control is linearly corrected, and the PID gain parameters in the torque control mode are synchronously linearly compensated. The method effectively solves the data distortion problem caused by the mechanical transmission gap, avoids the systematic underestimate of the hardness of the panel and the error adjustment of the control parameters, thereby eliminating the torque overshoot and oscillation, and improving the stability of the pressing process.

Description

Technical Field

[0001] This application relates to the field of ceiling machine technology, and in particular to a method and system for controlling the production process of ceiling machine panels. Background Technology

[0002] In modern industrial production, the pressing process of ceiling panel machines employs an automated pressing system, the core of which is a pressing torque control method applied to a multi-level feedback system. Based on pre-analysis of the stiffness and deformation curves of standard panels, this system sets the pressing head movement trajectory, torque intensity, and position-torque switching threshold, aiming to achieve smooth and precise pressing.

[0003] However, under long-term high-frequency operation, the microscopic wear of the ball screw and guide rail can easily lead to increased transmission chain clearance and reduced motion rigidity. This causes slight speed fluctuations and position feedback deviations during the position control stage. Especially at the initial moment when the pressing head contacts the panel, some of the motor torque is used to eliminate mechanical backlash rather than compress the panel, resulting in a pseudo-elastic region with a low slope in the acquired torque-position data. After linearly fitting the data in the detection window, the system continuously underestimates the actual stiffness of the panel.

[0004] Based on this erroneous judgment, the system adaptively delayed the switch from position control to torque control and increased the gain parameter of the torque controller. When the control switch occurred, the excessively high gain parameter was severely mismatched with the actually stiffer panel characteristics, causing severe instantaneous torque overshoot and high-frequency oscillations, making it difficult to stabilize at the target value. The upper-level correction logic attempted to intervene, but interfered with the lower-level erroneous timing adjustment, amplifying the oscillations instead. Since the root cause of the problem was data distortion due to mechanical backlash, conventional sensors and logs could not directly diagnose it, and traditional troubleshooting methods failed. Ultimately, the system fell into a self-deceptive failure state, not only failing to solve the initial material batch variation problem but also causing more serious pressing instability, forming a systemic technical dilemma that was difficult to troubleshoot.

[0005] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0006] In view of the shortcomings of the prior art, this application provides a method and system for controlling the production process of ceiling panel, which can effectively solve the problem of data distortion caused by mechanical transmission clearance, avoid systematic underestimation of the panel's hardness and incorrect adjustment of control parameters, thereby eliminating torque overshoot and oscillation, and has the advantage of improving the stability of the pressing process.

[0007] A first aspect is a method for controlling the production process of ceiling panel machines, the method comprising the following steps: S1: During the contact detection stage of the pressing mechanism pressing the panel to be pressed, the first force parameter and the first displacement parameter of the pressing mechanism are obtained; S2: Real-time monitoring of the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope; when the rate of change of the first slope reaches a preset abrupt change threshold, the current moment is determined as the phase switching point, and the phase switching point represents the transition of the pressing mechanism from the gap elimination state to the workpiece deformation state; S3: Extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and calculate the material property characterization value of the panel to be pressed based on it. The material property characterization value is the stiffness slope. S4: Based on the deviation between the stiffness slope and the preset standard slope, the displacement threshold for switching from the first control mode to the second control mode is linearly corrected, and the PID gain parameter in the second control mode is linearly compensated simultaneously.

[0008] Furthermore, step S1 includes: S11: Real-time monitoring of the distance between the pressing mechanism and the panel to be pressed, as well as the real-time force output by the pressing mechanism; S12: When the spacing is less than a preset distance threshold and the real-time force reaches a preset activation threshold, it is determined that the pressing mechanism is in the contact detection stage of pressing the panel to be pressed, and the material property detection window is opened. S13: Within the material property detection window, the real-time force is synchronously collected at a preset sampling frequency as the first force parameter, and the displacement parameter is synchronously collected as the first displacement parameter.

[0009] Furthermore, in step S2, real-time monitoring of the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope, includes the following steps: S21: Determine the instantaneous slope based on the ratio of the difference between the first force parameter and the difference between the first displacement parameter at adjacent sampling times; S22: Perform a moving average process on multiple consecutive instantaneous slopes to obtain the first-order slope; S23: Determine the rate of change of the first-order slope based on the ratio of the difference between the first-order slopes at adjacent time points to the difference between the displacement parameters.

[0010] Furthermore, in step S2, when the rate of change of the first-order slope reaches a preset abrupt change threshold, determining the current moment as the phase switching point includes the following steps: S24: Determine whether the number of times the rate of change of the first-order slope exceeds the mutation threshold has reached a preset number threshold. S25: If the preset number threshold is reached, the moment when the rate of change of the first slope first exceeds the abrupt change threshold is determined as the phase switching point.

[0011] Furthermore, step S3 includes: S31: Extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and take the second force parameter and the second displacement parameter during the period when the second force parameter is less than the preset termination threshold as the effective deformation data; S32: Perform linear fitting based on the effective deformation data to obtain the stiffness slope.

[0012] Furthermore, in step S4, the first control mode is a position control mode, and the second control mode is a torque control mode.

[0013] Furthermore, step S4 includes: S41: Calculate the deviation between the stiffness slope and the preset standard slope; S42: Based on the deviation value, calculate the dimensionless stiffness deviation rate, and then use the product of the stiffness deviation rate and the preset adjustment coefficient as a correction factor to proportionally correct the standard displacement threshold to obtain the displacement threshold. S43: Using the product of the stiffness deviation rate and the preset compensation coefficient as a compensation factor, proportional compensation is performed on the standard PID gain parameter to obtain the PID gain parameter.

[0014] Furthermore, after step S4, the method further includes: S5: Monitor in real time whether the displacement parameter reaches the corrected displacement threshold; S6: When the displacement parameter reaches the displacement threshold, the control of the pressing mechanism is switched from the first control mode to the second control mode, and the compensated PID gain parameter is loaded for closed-loop control.

[0015] Furthermore, the closed-loop control of the compensated PID gain parameters includes the following steps: S61: Obtain the real-time feedback torque value of the pressing mechanism at the switching moment, and set the real-time feedback torque value as the initial command value of the second control mode; S62: Calculate the torque compensation difference based on the initial command value and the preset target pressing torque value; S63: Within a preset gain smoothing period, the control gain of the pressing mechanism is linearly increased from the current real-time gain value to the compensated PID gain parameter, and torque compensation is performed synchronously according to the torque compensation difference, so that the force of the pressing mechanism smoothly transitions to the target pressing torque value.

[0016] Secondly, a ceiling panel production process control system, the system being used to implement the steps of any of the methods described above, the system comprising: The acquisition module is used to acquire the first force parameter and the first displacement parameter of the pressing mechanism during the contact detection stage when the pressing mechanism presses the panel to be pressed. The switching module is used to monitor in real time the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope; when the rate of change of the first slope reaches a preset abrupt change threshold, the current moment is determined as the phase switching point, and the phase switching point represents the transition of the pressing mechanism from the gap elimination state to the workpiece deformation state. An extraction module is used to extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and calculate the material property characterization value of the panel to be pressed, wherein the material property characterization value is the stiffness slope. The correction module is used to linearly correct the displacement threshold when switching from the first control mode to the second control mode based on the deviation between the stiffness slope and the preset standard slope, and simultaneously linearly compensate the PID gain parameter in the second control mode.

[0017] Beneficial Effects: The ceiling panel production process control method and system proposed in this application acquires the first force parameter and first displacement parameter of the pressing mechanism during the contact detection stage of the pressing mechanism pressing the panel to be pressed; monitors in real time the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope; when the rate of change of the first slope reaches a preset abrupt change threshold, the current moment is determined as the phase switching point, which represents the pressing mechanism transitioning from a gap elimination state to a workpiece deformation state; extracts the second force parameter and second displacement parameter after the phase switching point, and calculates the material property characterization value of the panel to be pressed based on this, which is the stiffness slope; based on the deviation value of the stiffness slope from the preset standard slope, linearly corrects the displacement threshold for switching from the first control mode to the second control mode, and simultaneously linearly compensates the PID gain parameter in the second control mode. Therefore, this method effectively solves the data distortion problem caused by mechanical transmission gaps, avoids the systematic underestimation of the panel's hardness and softness and the incorrect adjustment of control parameters, thereby eliminating torque overshoot and oscillation, and has the advantage of improving the stability of the pressing process. Attached Figure Description

[0018] Figure 1 This is a flowchart of a method for controlling the production process of ceiling panel machines proposed in this application.

[0019] Figure 2 This is a structural diagram of a ceiling panel production process control system proposed in this application.

[0020] Figure 3 This application presents a control logic block diagram for a ceiling panel production process control system.

[0021] Labeling explanation: 1. Pressing mechanism; 2. Panel to be pressed; 201. Acquisition module; 202. Switching module; 203. Extraction module; 204. Correction module. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The components of the embodiments of this application described and marked 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 represents 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.

[0023] 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.

[0024] To address the technical challenge of data distortion caused by transmission backlash in the pressing mechanism, which leads to a persistent underestimation of the panel's hardness and incorrect adjustment of control parameters, ultimately resulting in torque overshoot and oscillation, please refer to [reference needed]. Figure 1 This application provides a method for controlling the production process of ceiling panel machines, the method including the following steps: S1: During the contact detection stage of the pressing mechanism 1 pressing the panel 2 to be pressed, the first force parameter and the first displacement parameter of the pressing mechanism 1 are obtained; S2: Real-time monitoring of the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope; when the rate of change of the first slope reaches the preset abrupt change threshold, the current moment is determined as the phase switching point, and the phase switching point represents the transition of the pressing mechanism 1 from the gap elimination state to the workpiece deformation state. S3: Extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and calculate the material property characterization value of the panel 2 to be pressed based on this. The material property characterization value is the stiffness slope. S4: Based on the deviation between the stiffness slope and the preset standard slope, the displacement threshold for switching from the first control mode to the second control mode is linearly corrected, and the PID gain parameter in the second control mode is linearly compensated simultaneously.

[0025] The core idea of ​​this application is to no longer treat the initial contact stage between the pressing head and the panel as a single physical process, but instead automatically identify the boundary point between two different physical stages—gap elimination and workpiece deformation—based on the changing characteristics of force and displacement data. By accurately finding this switching point, only the workpiece deformation stage data is used to calculate the true material properties of the panel, and subsequent control strategies are dynamically adjusted based on these true properties, thereby fundamentally solving the problem of data distortion.

[0026] The entire pressing process is controlled by a high-performance industrial-grade programmable logic controller (PLC), such as the Siemens S7-1500 series. The power source for pressing mechanism 1 is a high-precision servo motor, which converts the rotational motion of the motor into the precise linear motion of the pressing head through a ball screw and linear guide mechanism.

[0027] During the contact detection stage of the pressing mechanism 1 pressing the panel 2 to be pressed, the driver of the high-precision servo motor will provide real-time feedback on its output torque or current value. After calibration, this value can represent the force applied by the pressing mechanism 1, i.e., the first force parameter.

[0028] The force signal is transmitted to the analog input module of the programmable logic controller at a frequency of 1kHz through the driver's built-in analog output interface, and is converted into a digital force value. At the same time, the precise position of the pressing head, i.e., the first displacement parameter, is measured in real time by a high-precision incremental encoder mounted on the motion axis, such as the Heidenhain ERM series encoder with a resolution of up to the micrometer level.

[0029] The encoder's pulse signal is directly input to the programmable logic controller via a high-speed counting module, providing precise position data of the pressing head at a frequency of 1kHz, which is completely synchronized with the force information. This high-frequency, synchronized data acquisition ensures that the subtle dynamic changes between the force and displacement at the moment of initial contact can be captured.

[0030] Furthermore, step S1 includes: S11: Real-time monitoring of the distance between the pressing mechanism 1 and the panel 2 to be pressed, as well as the real-time force output by the pressing mechanism 1; S12: When the spacing is less than the preset distance threshold and the real-time force reaches the preset start threshold, it is determined that the pressing mechanism 1 is in the contact detection stage of pressing the panel 2 to be pressed, and the material property detection window is opened. S13: Within the material property detection window, real-time force is synchronously acquired at a preset sampling frequency as the first force parameter, and displacement parameter is synchronously acquired as the first displacement parameter.

[0031] The spacing is calculated using the displacement encoder reading of the pressing head and the pre-calibrated panel surface position. Then, when the detected spacing is less than a preset distance threshold, such as 0.5 mm, indicating that the pressing head is about to contact the panel, and simultaneously the detected real-time force rises from zero to a preset activation threshold, such as 1 N·m, indicating that physical contact has actually occurred, the controller determines that the pressing process has entered the contact detection stage and immediately opens the logic window for material property detection. This dual-condition judgment mechanism effectively avoids false triggering caused by sensor zero-point drift or mechanical vibration. Finally, during the period when this material property detection window is activated, the controller synchronously and continuously collects and caches the real-time force as the first force parameter at a preset sampling frequency, such as 1 kHz, and synchronously collects the displacement parameter as the first displacement parameter, forming a series of force and displacement data pairs arranged in chronological order, providing high-quality raw data for subsequent slope analysis.

[0032] At the initial moment of contact, due to the mechanical transmission gap, the force increases relatively slowly, and the slope of the force-displacement curve is low. Once the gap is completely eliminated, the force begins to act directly on the panel, causing elastic deformation. At this point, the force increases rapidly with even a small displacement, leading to a sudden increase in the slope of the force-displacement curve. This abrupt change in slope marks the boundary between the gap-elimination state and the workpiece deformation state. The rate of change of the first-order slope, i.e., the second derivative of the force-displacement curve, is the most sensitive indicator for capturing this abrupt change.

[0033] Furthermore, in step S2, real-time monitoring of the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope, includes the following steps: S21: Determine the instantaneous slope based on the ratio of the difference between the first force parameter and the difference between the first displacement parameter at adjacent sampling times; S22: Perform a moving average on multiple consecutive instantaneous slopes to obtain the first-order slope; S23: Determine the rate of change of the first slope based on the ratio of the difference in the first slope to the difference in the displacement parameters at adjacent times.

[0034] The calculation in step S21 essentially uses the finite difference method to approximate the derivative of the curve at a certain point. For example, the instantaneous slope of the i-th sampling point can be obtained by... The calculation yields the result. However, since sensor data inevitably contains high-frequency noise, directly using the instantaneous slope may lead to drastic fluctuations in the results. Therefore, it is necessary to perform a moving average processing on multiple consecutive calculated instantaneous slopes to obtain a smoother first-order slope that better reflects the true trend. For example, the average of the most recent 5 instantaneous slope values ​​can be taken as the first-order slope at the current moment.

[0035] Moving average processing is a real-time filtering algorithm for sampled data streams. A fixed-length array is reserved in memory as a sliding window. As the sampling clock advances, newly acquired instantaneous slope values ​​are continuously added to the array, while the earliest values ​​added to the array are removed.

[0036] The controller calculates the arithmetic mean of all values ​​within the window and outputs the result as the current first-order slope. The length of the sliding window is set according to the ratio of the sampling frequency to the mechanical vibration frequency. It is usually selected to be long enough to filter out high-frequency electromagnetic noise without causing severe phase lag, thus providing a smooth and stable data basis for subsequent rate of change calculations.

[0037] Finally, the rate of change of the first-order slope is determined by the ratio of the difference in the smoothed first-order slope calculated at adjacent time points to the difference in the corresponding displacement parameters. This calculation process also uses the finite difference method, which is equivalent to differentiating the first-order slope sequence again, thereby obtaining the second derivative of the force-displacement curve.

[0038] Furthermore, in step S2, when the rate of change of the first-order slope reaches a preset abrupt change threshold, determining the current moment as the phase switching point includes the following steps: S24: Determine whether the number of times the rate of change of the first-order slope exceeds the mutation threshold has reached the preset number threshold. S25: If the preset number of times threshold is reached, the moment when the rate of change of the first slope first exceeds the mutation threshold is determined as the phase switching point.

[0039] When the calculated rate of change of the first-order slope reaches a preset abrupt change threshold, for example... The controller then determines the current moment as the phase switching point. The mutation threshold is a critical value stored within the logic control unit used to determine changes in the mechanical state. The specific process of determining this value involves a no-load and load comparison experiment conducted during the equipment commissioning phase.

[0040] By simulating the motion of the pressing mechanism 1 under different lubrication conditions and component wear levels, multiple sets of second-derivative characteristic curves of torque as a function of displacement were obtained. The sudden change in characteristic current generated at the moment of gap elimination was converted into a slope change rate in a physical sense, and a slope change rate average that can completely cover mechanical background noise interference and has significant discrimination was selected as the sudden change threshold.

[0041] During production, the controller compares the real-time second derivative with the preset value to determine whether the gap in the mechanical transmission chain has been completely closed. This phase switching point physically clearly indicates that the pressing mechanism 1 has completely overcome the transmission gap and has officially transitioned from the gap elimination state to the workpiece deformation state.

[0042] To further enhance the reliability of the judgment and avoid misjudgments caused by noise spikes in a single data point, the process of determining the phase switching point also includes a confirmation mechanism. Specifically, the controller determines whether the rate of change of the first-order slope has exceeded a preset threshold number of consecutive times, such as three consecutive times. Only when this condition is met is a true and sustained slope abrupt change confirmed. Furthermore, if the preset threshold is reached, the controller accurately determines the moment when the rate of change of the first-order slope first exceeds the threshold as the final phase switching point. This backtracking approach ensures that the determined switching point is as close as possible to the true starting point of the physical state transition.

[0043] It is worth noting that while a simple pressure detector installed between the pressing head and the panel can determine whether contact has occurred, in situations with mechanical transmission backlash (such as idle stroke caused by ball screw wear), the pressure detector will output a tiny force signal at the initial moment the pressing head contacts the panel. This force signal does not originate from the elastic deformation of the panel, but rather from the force generated by the motor overcoming the transmission chain backlash. If a simple pressure threshold is used (for example, determining that workpiece deformation has begun when the detected force exceeds a certain preset value), the entire backlash elimination stage will be misjudged as the workpiece deformation stage. This will lead to a large amount of pseudo-elasticity data being mixed into the subsequent stiffness calculation data, ultimately systematically underestimating the actual stiffness of the panel. In other words, a simple force threshold detection can only indicate whether contact has occurred, but cannot distinguish whether the contact has been effectively transmitted to the panel, let alone accurately identify the critical moment when the mechanical backlash has been completely eliminated and the workpiece begins to undergo true elastic deformation.

[0044] Therefore, this application uses a method based on the first-order slope change rate to identify the phase switching point. Compared with the traditional simple pressure threshold detection, this method identifies the phase switching point between gap elimination and workpiece deformation by calculating the first-order slope change rate of the force-displacement curve in real time. This can effectively eliminate the pseudo-elastic data interference caused by mechanical transmission gaps, obtain the true stiffness characteristics of the panel, and thus fundamentally avoid the incorrect adjustment of control parameters, achieving adaptive and stable pressing.

[0045] Furthermore, step S3 includes: S31: Extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and take the second force parameter and the second displacement parameter during the period when the second force parameter is less than the preset termination threshold as the effective deformation data; S32: Perform linear fitting based on the effective deformation data to obtain the stiffness slope.

[0046] First, from the acquired complete data sequence, all second force and second displacement parameters recorded after the phase switching point are extracted. This eliminates all interference data containing distorted information generated during the gap elimination stage. However, not all extracted data is used for calculation. To ensure that the analysis focuses on the linear elastic deformation stage of the panel, an upper limit for the force needs to be set.

[0047] Therefore, all second force parameters and second displacement parameters in the extracted data that are less than a preset termination threshold, such as 10 N·m, are taken as the final effective deformation data. This termination threshold is set to prevent the panel from entering the nonlinear or plastic deformation region when the force is too large, thus ensuring that the data points used for calculation fall within a stable elastic range. Then, based on these rigorously selected effective deformation data, linear fitting is performed to obtain the stiffness slope. The most commonly used linear fitting method is the least squares method, which calculates the slope of a straight line that best represents the distribution trend of these effective data points. This calculated slope is the true stiffness slope of the current panel 2 to be pressed, accurately characterizing its true hardness.

[0048] Furthermore, in step S4, the first control mode is the position control mode, and the second control mode is the torque control mode.

[0049] In step S4, linear correction and linear compensation are based on deviation-driven dynamic parameter adjustment logic. A linear proportional mathematical relationship is established within the controller. This relationship associates the measured value of material stiffness with the optimal value of the control parameters. When the calculated stiffness slope deviates from the standard value, the deviation is input to the proportional calculation stage. The adjustment coefficient is responsible for converting the stiffness difference into the advance or delay of the displacement switching point.

[0050] The compensation coefficients are responsible for converting stiffness differences into increases or decreases in the controller's proportional and integral gains. The values ​​of these coefficients were obtained through extensive pressing envelope tests on panels of different materials, ensuring that the control algorithm can achieve a constant pressing effect through parameter compensation even when material properties fluctuate slightly. The standard slope here is based on benchmark values ​​measured from numerous standard panel experiments. The first control mode in the entire pressing process is a position control mode, whose task is to drive the pressing head to the predetermined position quickly and accurately. The second control mode is a force control mode, whose task is to apply and maintain a precise target pressing force after the pressing head contacts the panel.

[0051] Furthermore, step S4 includes: S41: Calculate the deviation between the stiffness slope and the preset standard slope; S42: Based on the deviation value, calculate the dimensionless stiffness deviation rate, and then use the product of the stiffness deviation rate and the preset adjustment coefficient as a correction factor to proportionally correct the standard displacement threshold to obtain the displacement threshold. S43: The standard PID gain parameters are proportionally compensated based on the product of the stiffness deviation rate and the preset compensation coefficient as the compensation factor to obtain the PID gain parameters.

[0052] The deviation value directly quantifies the difference in hardness and softness between the current panel and the standard panel.

[0053] It should be noted that the above corrections and compensations are based on proportional calculations using the dimensionless stiffness deviation rate, avoiding the mathematical drawbacks of directly adding or subtracting physical quantities with different dimensions. The stiffness deviation rate is defined as (standard slope - true stiffness slope) / standard slope, a purely proportional value. The preset adjustment and compensation coefficients are dimensionless constants calibrated experimentally, and their physical meaning is the relative change ratio of the displacement threshold or gain parameter caused by a unit stiffness deviation rate. This proportional correction method ensures that the dimensions on both sides of the equation are consistent and facilitates parameter transfer and calibration in panel lamination systems of different specifications.

[0054] Next, the standard displacement threshold is proportionally corrected using the product of the calculated dimensionless stiffness deviation rate and the preset adjustment coefficient as a correction factor, thus obtaining a dynamically adjusted displacement threshold. For example, the correction adopts a dimensionless linear correction relationship based on the stiffness deviation ratio.

[0055] First, calculate the relative stiffness deviation rate: Stiffness deviation rate = (Standard slope - True stiffness slope) / Standard slope. This stiffness deviation rate is a dimensionless quantity that reflects the degree of deviation of the current panel stiffness from the standard stiffness.

[0056] Then, the standard displacement threshold is linearly corrected based on the product of the stiffness deviation rate and a preset adjustment coefficient (a dimensionless constant): Corrected displacement threshold = Standard displacement threshold × (1 + Adjustment coefficient × Stiffness deviation rate). The adjustment coefficient is a dimensionless empirical constant, typically ranging from 0 to 1, and is pre-calibrated through pressing experiments on panels with different stiffnesses. If the actual stiffness slope is greater than the standard slope (the panel is stiffer), the stiffness deviation rate is negative, the corrected displacement threshold decreases, and the switching point is advanced; conversely, if the panel is softer, the stiffness deviation rate is positive, the corrected displacement threshold increases, and the switching point is delayed. The dimensions on both sides of this formula are consistent (both are lengths).

[0057] Meanwhile, the product of the dimensionless stiffness deviation rate and the preset compensation coefficient is used as the compensation factor to proportionally compensate the standard PID gain parameters, resulting in dynamically adjusted PID gain parameters. For example, the proportional gain compensation uses the same dimensionless deviation rate for linear compensation: Compensated proportional gain = Standard proportional gain × (1 + Compensation coefficient × Stiffness deviation rate). The compensation coefficient is a dimensionless empirical constant, typically ranging from -1 to 1, and is pre-calibrated through closed-loop control response experiments under different stiffness panels. The stiffness deviation rate is defined as above. If the panel is too stiff (the actual stiffness slope is greater than the standard slope, and the stiffness deviation rate is negative), the compensated proportional gain decreases, resulting in a gentler torque controller response and preventing overshoot; if the panel is too soft (the stiffness deviation rate is positive), the compensated proportional gain increases, ensuring a faster response. The dimensions on both sides of this formula are consistent (both are gain dimensions), making the compensation logic clear. Similarly, the compensation formula for integral gain is: Compensated integral gain = Standard integral gain × (1 + Compensation coefficient _i × Stiffness deviation rate), where the compensation coefficient _i is a dimensionless constant calibrated separately for integral gain.

[0058] As a specific implementation, in a pressing scenario for high-stiffness composite material panels, the pressing mechanism 1 needs to handle workpieces with extremely high surface hardness. In this environment, even minor material deformation can cause drastic jumps in the feedback torque. After obtaining the stiffness slope, the logic unit immediately compares it with the standard slope. If the stiffness of the current panel shows a significant hardening trend, and the deviation value increases positively, the controller will trigger protective parameter offset logic. The linear correction of the displacement threshold will proceed in the direction of reducing the pressing depth, meaning that the position control mode will exit early and be taken over by the torque mode, utilizing the closed-loop flexibility of the torque mode to buffer the mechanical collision at the moment of contact. The synchronous PID gain linear compensation will reduce the proportional gain of the current control loop, suppressing high-frequency oscillations caused by hard contact by weakening the controller's sensitivity. This parameter adaptive strategy based on material stiffness feedback allows the pressing mechanism 1 to reconstruct its control surface in real time according to the actual mechanical performance of each panel, avoiding the fragility of a single static parameter in the face of batch material differences, and ensuring that the force on the pressing interface remains uniform and stable even when there are fluctuations in the workpiece hardness.

[0059] After the dynamic adjustment of the control parameters is completed, the method enters the execution phase. Specifically, after step S4, the method also includes: S5: Real-time monitoring to see if the displacement parameters reach the corrected displacement threshold; S6: When the displacement parameter reaches the displacement threshold, the control of the pressing mechanism 1 is switched from the first control mode to the second control mode, and the compensated PID gain parameter is loaded for closed-loop control.

[0060] When the displacement parameter precisely reaches the displacement threshold corresponding to the current panel 2 to be pressed, the control of the pressing mechanism 1 is immediately switched from the first control mode, i.e., the position control mode, to the second control mode, i.e., the torque control mode, and the compensated PID gain parameter is loaded for closed-loop control.

[0061] As a specific implementation method, in a multi-axis linkage production line, to prevent stress spikes and mechanical oscillations in the pressing mechanism due to abrupt changes in control parameters, this embodiment designs a gradual control parameter smooth transition mechanism. This mechanism synchronously and gradually adjusts the control gain and torque command at the instant of control mode switching. The specific implementation steps are as follows: First, the triggering conditions for the smooth transition mechanism are defined. When the real-time displacement parameters of the pressing mechanism 1 fed back by the displacement sensor enter the displacement threshold range after linear correction in the aforementioned step S42 (for example, reaching 90% to 100% of the corrected displacement threshold), the underlying servo driver of the pressing mechanism 1 (hereinafter referred to as the driver) triggers the mode takeover protocol, preparing to switch from position control mode to torque control mode. This protocol defines the behavior sequence of the driver during the switching process, including: freezing the output of the current position loop, buffering the current torque feedback value, and activating the gain smoothing and torque compensation algorithm.

[0062] Secondly, at the moment of switching, initial state locking and mapping are performed. The driver performs the following operations: Read the real-time feedback torque value M_current of the pressing mechanism 1 at the current moment, and set it as the initial value M_initial of the torque command in the torque control mode (i.e., M_initial=M_current). At the same time, preset the integral term (IntegralTerm) of the torque controller to M_initial to achieve a disturbance-free switching.

[0063] The locked M_initial is directly mapped to the initial reference point of the torque control mode to ensure the continuity of the force before and after the switch and avoid jumps in the command value.

[0064] Then, the PID gain parameters are progressively loaded. This application uses a gain weighting function to achieve a smooth online transition of the PID parameters, rather than an instantaneous replacement. Specifically: Define a gain smoothing period T_smooth (e.g., a fixed value between 50 ms and 200 ms, which can be pre-calibrated according to the response speed of the mechanical system). Within this period, define a gain weighting factor λ(t), which is a monotonically increasing function of time t. A preferred linear function form is: λ(t) = t / T_smooth, where t increases from 0 to T_smooth.

[0065] Within each control cycle (e.g., 1 millisecond) of the T_smooth period, the driver calculates the currently used real-time gain K(t) by weighting the old and new gains based on λ(t). The calculation formula is: K(t) = (1-λ(t))*K_old + λ(t)*K_new. Wherein, K_old is the current real-time gain value before the switching instant, i.e., the speed loop proportional gain in position control mode. K_new is the target PID gain parameter obtained after linear compensation in the aforementioned step S43, i.e., the proportional gain (Kp_new) and integral gain (Ki_new) in torque control mode.

[0066] Finally, torque compensation is performed synchronously. While smoothing the gain, the driver performs synchronous torque compensation to compensate for the target torque difference caused by variations in panel stiffness: Calculate the torque compensation difference: Based on the preset target pressing torque value M_target and the initial command value M_initial at the time of switching, calculate the total compensation difference ΔM=M_target-M_initial.

[0067] Synchronization compensation is performed: Within the same gain smoothing period T_smooth, the control torque command M(t) increases linearly from M_initial to M_target according to the same rule as the gain weighting function λ(t). Its expression is: M(t) = M_initial + λ(t) * ΔM.

[0068] Through the above mechanism, during the entire transition period from position control mode to torque control mode, the control gain K(t) and torque command M(t) of the pressing mechanism 1 both achieve smooth and synchronous linear changes. This effectively eliminates force spikes and high-frequency oscillations caused by parameter jumps, ensuring that the drive current transition curve of the servo motor remains continuous and smooth during the process of the pressing head transitioning from a free-moving state to a stressed deformation state, and ultimately stabilizes at the target pressing torque M_target.

[0069] By adjusting the micro-control logic at the millisecond scale, the instantaneous overshoot phenomenon that easily occurs at the end of the long-stroke pressing is solved, and the fault tolerance of the production equipment to complex mechanical environments and workpiece differences is significantly improved.

[0070] To ensure an absolutely smooth transition from position control to torque control and avoid any form of shock or disturbance, further closed-loop control is performed by applying compensated PID gain parameters, including the following steps: S61: Obtain the real-time feedback torque value of the pressing mechanism 1 at the switching moment, and set the real-time feedback torque value as the initial command value of the second control mode; S62: Calculate the torque compensation difference based on the initial command value and the preset target pressing torque value; S63: Within the preset gain smoothing period, the control gain of the pressing mechanism 1 is linearly increased from the current real-time gain value to the compensated PID gain parameter, and torque compensation is performed synchronously according to the torque compensation difference, so that the force of the pressing mechanism 1 is smoothly transitioned to the target pressing torque value.

[0071] First, setting the real-time feedback torque value of the pressing mechanism 1 at the switching moment as the initial command value of the second control mode ensures a seamless transition between the initial target of torque control and the actual state before the switch, avoiding jumps in the command value. Second, a torque compensation difference is calculated based on this initial command value and the final preset target pressing torque value. This difference represents the torque range that needs to be smoothly transitioned. Finally, within a preset, extremely short gain smoothing cycle, the control gain of the pressing mechanism 1 linearly and smoothly increases from the current real-time gain value before the switch to the compensated PID gain parameter. While the gain smoothly increases, torque command compensation is performed synchronously based on the calculated torque compensation difference, so that the force applied by the pressing mechanism 1 can smoothly and without impact transition from the initial torque value at the time of switching to the final target pressing torque value. This combined mechanism, which includes initial value setting, torque difference compensation, and gain smoothing transition, ensures an extremely smooth control switch, fundamentally eliminating the risk of overshoot and oscillation.

[0072] Through the aforementioned series of steps, the method proposed in this application can perceive and compensate for data distortion introduced by mechanical transmission gaps online and in real time, accurately calculate the true material properties of each panel 2 to be pressed, and make immediate and precise dynamic adjustments to the control strategy accordingly. This closed-loop adaptive control method not only effectively avoids torque overshoot and oscillation, significantly improving the stability of the pressing process and product quality, but more importantly, it frees the entire production process from dependence on ideal mechanical states and the tedious work of repeated manual calibration, achieving a higher level of automation and intelligence.

[0073] Please refer to Figure 2 , Figure 3 A ceiling panel production process control system, the system being used to implement the steps of any of the above methods, the system comprising: The acquisition module 201 is used to acquire the first force parameter and the first displacement parameter of the pressing mechanism 1 during the contact detection stage when the pressing mechanism 1 presses the panel 2 to be pressed. The switching module 202 is used to monitor the first slope of the first force parameter relative to the first displacement parameter and the rate of change of the first slope in real time. When the rate of change of the first slope reaches the preset abrupt change threshold, the current moment is determined as the phase switching point. The phase switching point represents the transition of the pressing mechanism 1 from the gap elimination state to the workpiece deformation state. The extraction module 203 is used to extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and calculate the material property characterization value of the panel 2 to be pressed based on it. The material property characterization value is the stiffness slope. The correction module 204 is used to linearly correct the displacement threshold when switching from the first control mode to the second control mode based on the deviation between the stiffness slope and the preset standard slope, and simultaneously linearly compensate the PID gain parameter in the second control mode.

[0074] Specifically, the acquisition module 201 may include a force sensor, a displacement sensor, and a data acquisition unit. The force sensor is used to measure the first force parameter applied by the pressing mechanism 1 in real time; for example, a piezoelectric force sensor or a strain gauge force sensor may be used. The displacement sensor is used to measure the first displacement parameter of the pressing mechanism 1 in real time; for example, a grating ruler, encoder, or laser displacement sensor may be used. The data acquisition unit is responsible for synchronously acquiring the analog signals output by these sensors at a preset sampling frequency, converting them into digital signals, and storing them in a memory for subsequent processing. As an alternative, the acquisition module 201 may also indirectly acquire the force and displacement parameters by monitoring the current and rotation angle of the motor driving the pressing mechanism 1; for example, the force can be calculated from the current value fed back by the motor driver, and the displacement can be calculated from the rotation angle value fed back by the encoder.

[0075] The switching module 202 can be implemented by a processor in the system executing a specific algorithm. The processor receives the first force parameter and the first displacement parameter acquired by the acquisition module, and calculates in real time the first slope of the first force parameter relative to the first displacement parameter and the rate of change of the first slope. For example, the processor can use a differential calculation combined with a moving average filter to obtain a smooth first slope, and then obtain its rate of change through further differential calculation. When the calculated rate of change of the first slope reaches a preset abrupt change threshold, the processor marks the current moment as a phase switching point. This abrupt change threshold can be determined based on empirical values ​​or through experimental calibration.

[0076] The extraction module 203 can also be implemented by the processor in the system executing data processing algorithms. After receiving the phase switching point determined by the switching module, the processor extracts a segment of force and displacement parameters after the phase switching point from the memory as the second force and second displacement parameters. To ensure the validity of the data, a data extraction range or termination condition can be set, for example, data extraction can be performed within a preset deformation depth range. Subsequently, the processor performs linear fitting on these extracted second force and second displacement parameters, for example, using the least squares method, to calculate the material property characterization value of the panel 2 to be pressed, i.e., the stiffness slope.

[0077] The correction module 204 can also be implemented by the processor in the system executing a control parameter adjustment algorithm. The processor receives the stiffness slope calculated by the extraction module and compares it with a preset standard slope to calculate the deviation value between the two. Based on this deviation value, the processor performs a linear correction on the displacement threshold when switching from the first control mode to the second control mode. For example, the correction amount can be calculated by multiplying the deviation value by a preset adjustment coefficient and then superimposed on the standard displacement threshold. At the same time, the processor also performs linear compensation on the PID gain parameter in the second control mode based on the deviation value. For example, the compensation amount can be calculated by multiplying the deviation value by a preset compensation coefficient and then superimposed on the standard PID gain parameter. The corrected displacement threshold and the compensated PID gain parameter will be loaded into the controller of the pressing mechanism 1 to guide subsequent pressing operations.

[0078] The ceiling panel production process control system of this application represents a significant improvement over existing technologies. In traditional automated pressing systems, mechanical wear leads to increased transmission chain clearance during long-term operation. This causes some of the motor torque to be used to eliminate mechanical clearance rather than effectively compress the panel during the initial contact with the panel. This results in a pseudo-elastic region with a low slope in the collected torque-position data, thus underestimating the actual stiffness of the panel 2 to be pressed. Based on this erroneous stiffness assessment, the system delays the control mode switching and incorrectly increases the gain parameter of the torque controller, ultimately causing severe instantaneous torque overshoot and high-frequency oscillations.

[0079] The control system of this application achieves precise perception and adaptive control of the pressing process by introducing an acquisition module 201, a switching module 202, an extraction module 203, and a correction module 204. Among these, the switching module can accurately identify the phase switching point where the pressing mechanism 1 transitions from a gap elimination state to a workpiece deformation state, which is one of the core innovations of this application. In this way, the system can avoid the data distortion problem caused by mechanical gaps in traditional methods, ensuring that the stiffness slope calculated by the extraction module 203 truly reflects the material properties of the panel. Based on the accurate stiffness slope, the correction module 204 can adaptively perform linear correction and compensation on the displacement threshold and PID gain parameters of the control mode switching. This modular system design and intelligent control strategy enable the control parameters of the pressing process to match the actual stiffness of the panel in real time, thereby effectively suppressing instantaneous torque overshoot and high-frequency oscillations, significantly improving the stability and product quality of the ceiling machine panel pressing process, and overcoming the systemic technical difficulties that are difficult to detect in existing technologies.

[0080] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for controlling the production process of ceiling panel making machines, characterized in that, The method includes the following steps: S1: During the contact detection stage of the pressing mechanism pressing the panel to be pressed, the first force parameter and the first displacement parameter of the pressing mechanism are obtained; S2: Real-time monitoring of the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope; when the rate of change of the first slope reaches a preset abrupt change threshold, the current moment is determined as the phase switching point, and the phase switching point represents the transition of the pressing mechanism from the gap elimination state to the workpiece deformation state; S3: Extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and calculate the material property characterization value of the panel to be pressed based on it. The material property characterization value is the stiffness slope. S4: Based on the deviation between the stiffness slope and the preset standard slope, the displacement threshold for switching from the first control mode to the second control mode is linearly corrected, and the PID gain parameter in the second control mode is linearly compensated simultaneously.

2. The method for controlling the production process of ceiling panel as described in claim 1, characterized in that, Step S1 includes: S11: Real-time monitoring of the distance between the pressing mechanism and the panel to be pressed, as well as the real-time force output by the pressing mechanism; S12: When the spacing is less than a preset distance threshold and the real-time force reaches a preset activation threshold, it is determined that the pressing mechanism is in the contact detection stage of pressing the panel to be pressed, and the material property detection window is opened. S13: Within the material property detection window, the real-time force is synchronously collected at a preset sampling frequency as the first force parameter, and the displacement parameter is synchronously collected as the first displacement parameter.

3. The method for controlling the production process of ceiling panel as described in claim 1, characterized in that, In step S2, real-time monitoring of the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope, includes the following steps: S21: Determine the instantaneous slope based on the ratio of the difference between the first force parameter and the difference between the first displacement parameter at adjacent sampling times; S22: Perform a moving average process on multiple consecutive instantaneous slopes to obtain the first-order slope; S23: Determine the rate of change of the first-order slope based on the ratio of the difference between the first-order slopes at adjacent time points to the difference between the displacement parameters.

4. The method for controlling the production process of ceiling panel as described in claim 3, characterized in that, In step S2, when the rate of change of the first-order slope reaches a preset abrupt change threshold, determining the current moment as the phase switching point includes the following steps: S24: Determine whether the number of times the rate of change of the first-order slope exceeds the mutation threshold has reached a preset number threshold. S25: If the preset number threshold is reached, the moment when the rate of change of the first slope first exceeds the abrupt change threshold is determined as the phase switching point.

5. The method for controlling the production process of ceiling panel as described in claim 1, characterized in that, Step S3 includes: S31: Extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and take the second force parameter and the second displacement parameter during the period when the second force parameter is less than the preset termination threshold as the effective deformation data; S32: Perform linear fitting based on the effective deformation data to obtain the stiffness slope.

6. The method for controlling the production process of ceiling panel as described in claim 1, characterized in that, In step S4, the first control mode is the position control mode, and the second control mode is the torque control mode.

7. The method for controlling the production process of ceiling panel as described in claim 1, characterized in that, Step S4 includes: S41: Calculate the deviation between the stiffness slope and the preset standard slope; S42: Based on the deviation value, calculate the dimensionless stiffness deviation rate, and then use the product of the stiffness deviation rate and the preset adjustment coefficient as a correction factor to proportionally correct the standard displacement threshold to obtain the displacement threshold. S43: Using the product of the stiffness deviation rate and the preset compensation coefficient as a compensation factor, proportional compensation is performed on the standard PID gain parameter to obtain the PID gain parameter.

8. The method for controlling the production process of ceiling panel as described in claim 1, characterized in that, After step S4, the method further includes: S5: Monitor in real time whether the displacement parameter reaches the corrected displacement threshold; S6: When the displacement parameter reaches the displacement threshold, the control of the pressing mechanism is switched from the first control mode to the second control mode, and the compensated PID gain parameter is loaded for closed-loop control.

9. A method for controlling the production process of ceiling panel as described in claim 8, characterized in that, In step S6, loading the compensated PID gain parameters for closed-loop control includes the following steps: S61: Obtain the real-time feedback torque value of the pressing mechanism at the switching moment, and set the real-time feedback torque value as the initial command value of the second control mode; S62: Calculate the torque compensation difference based on the initial command value and the preset target pressing torque value; S63: Within a preset gain smoothing period, the control gain of the pressing mechanism is linearly increased from the current real-time gain value to the compensated PID gain parameter, and torque compensation is performed synchronously according to the torque compensation difference, so that the force of the pressing mechanism smoothly transitions to the target pressing torque value.

10. A control system for the production process of ceiling panel machines, characterized in that, The system is used to implement the steps of the method according to any one of claims 1-9, and the system includes: The acquisition module is used to acquire the first force parameter and the first displacement parameter of the pressing mechanism during the contact detection stage when the pressing mechanism presses the panel to be pressed. The switching module is used to monitor in real time the first slope of the first force parameter relative to the first displacement parameter, and the rate of change of the first slope; when the rate of change of the first slope reaches a preset abrupt change threshold, the current moment is determined as the phase switching point, and the phase switching point represents the transition of the pressing mechanism from the gap elimination state to the workpiece deformation state. An extraction module is used to extract the first force parameter and the first displacement parameter after the phase switching point as the second force parameter and the second displacement parameter, and calculate the material property characterization value of the panel to be pressed, wherein the material property characterization value is the stiffness slope. The correction module is used to linearly correct the displacement threshold when switching from the first control mode to the second control mode based on the deviation between the stiffness slope and the preset standard slope, and simultaneously linearly compensate the PID gain parameter in the second control mode.

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