CN-121973306-A - Intelligent control system for hot press forming process of short fiber reinforced fiberboard

CN121973306ACN 121973306 ACN121973306 ACN 121973306ACN-121973306-A

Abstract

The invention discloses an intelligent control system for a hot press forming process of a short fiber reinforced fiberboard, which relates to the technical field of intelligent control and comprises the steps of capturing stress wave pulses through a monitoring window which is dynamically opened and closed along with pressure load under the constraint of initial forming reference parameters, projecting acoustic emission signals to a time-frequency cooperative domain, extracting fiber damage variables through the intensity stripping of energy distribution, mapping the fiber damage variables into structural disturbance parameters of an internal structural evolution state of the short fiber reinforced fiberboard, carrying out coupling analysis on the structural disturbance parameters and pressure change information detected in the forming process to form structural disturbance estimation parameters, mapping the structural disturbance estimation parameters into synchronous abnormal phase compensation components, injecting transient driving correction instructions which counteract disturbance energy in a pressure control loop, outputting a forming state data stream, reducing layering burst and warping risks of a finished product and improving the comprehensive mechanical property of the short fiber reinforced fiberboard.

Inventors

LIU PEISHENG
ZHANG YIBIN
ZHANG YUECHANG

Assignees

濮阳市森大木业有限公司

Dates

Publication Date: 20260505
Application Date: 20260210

Claims (10)

1. An intelligent control system for a hot press forming process of a short fiber reinforced fiberboard is characterized by comprising: The acquisition module acquires slab multidimensional physical property characteristic parameters of the short fiber reinforced slab to be processed, and performs environmental noise suppression on the acoustic emission acquisition channel to obtain initial forming reference parameters; The damage sensing module captures stress wave pulses through a monitoring window which is dynamically opened and closed along with pressure load under the constraint of initial forming reference parameters, projects acoustic emission signals to a time-frequency cooperative domain, and extracts fiber damage variables through the intensity stripping of energy distribution; The disturbance module maps the fiber damage variable into a structural disturbance parameter of an internal structural evolution state of the short fiber reinforced slab, and performs coupling analysis on the structural disturbance parameter and pressure change information detected in the forming process to form a structural disturbance estimation parameter; The adjusting module maps the structural disturbance estimation parameters into synchronous heterogeneous phase compensation components, injects transient driving correction instructions which are counteracted with disturbance energy into the pressure control loop, and outputs a molding state data stream; and the pressure relief module is used for judging the solidification completion state based on the molding state data flow and driving the hot pressing executing mechanism to execute nonlinear stress relaxation and pressure reduction control according to the structural disturbance estimation parameters.
2. An intelligent control system for a hot press forming process of a short fiber reinforced plastic sheet according to claim 1, wherein the method for obtaining initial forming reference parameters comprises: Collecting information of fiber content, slab thickness, initial density and water content of a short fiber reinforced slab to be processed, and carrying out parameter standardization treatment to obtain multidimensional physical characteristic parameters of the slab; And performing dynamic zero calibration on the acoustic emission acquisition channel by using the environmental noise characteristic parameters, and performing multidimensional characteristic association mapping by combining the multidimensional physical characteristic parameters of the plate blank to construct a molding initial reference parameter.
3. The intelligent control system for a hot press forming process of a short fiber reinforced fiberboard according to claim 2, wherein the method for obtaining the fiber damage variable comprises the steps of: Determining an execution range of a monitoring window which is dynamically opened and closed along with the pressure load by combining with the real-time pressure load partition based on the upper limit of the amplitude of the environmental background signal in the initial forming reference parameter as an opening threshold; Capturing stress wave pulses in an execution range of a monitoring window, and carrying out band-pass filtering to obtain an acoustic emission signal; performing energy gravity center positioning on the three-dimensional distribution map, and extracting an energy threshold value according to the deviation degree of the background energy plane and the energy amplitude of the gravity center area; And performing amplitude sampling and counting accumulation on the characteristic frequency components to obtain a pulse characteristic set, performing contribution coupling on the acoustic emission energy release rate and the pulse accumulation counting in the pulse characteristic set, and extracting fiber damage variables.
4. A system for intelligently controlling a hot press forming process of a short fiber reinforced fiberboard according to claim 3, wherein the method for mapping fiber damage variables into structural disturbance parameters of an internal structural evolution state of the short fiber reinforced fiberboard comprises: Performing smoothing treatment on the fiber damage variable to obtain a fiber damage variable change rate, performing characteristic gain fusion on the fiber damage variable change rate and a molding initial reference parameter to obtain a transient energy consumption characteristic value of energy fluctuation at the current moment; performing associated gain mapping based on stiffness sensitivity on microscopic energy consumption increment in the short fiber reinforced plate blank by using the initial molding reference parameters, and determining a structural degradation index for representing the stiffness attenuation degree of the fiber skeleton; And converting the structural degradation index into a feedback compensation value consistent with the pressure unit to obtain the structural disturbance parameter of the internal structural evolution state of the short fiber reinforced slab.
5. The intelligent control system for a hot press forming process of a short fiber reinforced plastic sheet according to claim 4, wherein the method for forming the structural disturbance estimation parameter comprises: acquiring a real-time pressure feedback value of an executing mechanism of the hot press by using a pressure sensor, and acquiring pressure change information detected in the forming process by extracting fluctuation displacement characteristics of adjacent sampling positions; performing time axis translation on the structural disturbance parameter according to the time stamp difference value of the structural disturbance parameter and the pressure change information, and realizing phase alignment of the structural disturbance parameter and the pressure change information detected in the forming process; intercepting a continuous fixed length sequence of the structural disturbance parameter and pressure change information detected in the forming process before the current sampling time, executing time sequence association, matching and fusion between the sequences, evaluating waveform similarity based on the change trend of fusion feature quantity along with time, and extracting a pressure fluctuation component caused by internal structural evolution; and performing gain correlation fusion on the structural disturbance parameters by using the pressure fluctuation component, and filtering out mechanical error interference to form structural disturbance estimation parameters.
6. The intelligent control system for a hot press forming process of a short fiber reinforced plastic sheet according to claim 5, wherein the method for mapping the structural disturbance estimation parameter into the synchronous heterogeneous phase compensation component comprises: the transient phase is identified through the waveform slope and the amplitude polarity of the structural disturbance estimation parameter, and the complementary phase value is selected from the phase coordinate system according to the transient phase, so as to determine the reverse compensation phase offset; And loading the image amplitude signal to the reverse compensation phase offset, performing signal recombination of amplitude and phase by locking a sampling time reference, and taking the recombined reverse hedging waveform as a synchronous heterophase compensation component.
7. The intelligent control system for a hot press forming process of a short fiber reinforced plastic panel according to claim 6, wherein the method for outputting the forming state data stream comprises: the method comprises the steps of extracting the opening degree of a servo valve and the displacement of a hydraulic pump of an actuating mechanism in a pressure control loop in real time, analyzing and obtaining the current control gain of the pressure control loop, performing scale coordination conversion on a synchronous heterophase compensation component and the current control gain of the pressure control loop, and determining the amplitude of an electric signal of a transient driving correction instruction; Adding the amplitude of the electric signal to the original given signal of the pressure control loop to finish the injection of a transient driving correction instruction which counteracts disturbance energy in the pressure control loop; and collecting feedback pressure, displacement change rate and slab surface temperature of the hydraulic actuating mechanism under the action of the transient driving correction instruction in real time, packaging the feedback pressure, displacement change rate and slab surface temperature into a continuous data sequence with a timestamp mark, and outputting a molding state data stream.
8. The intelligent control system for hot press forming process of short fiber reinforced fiber board according to claim 7, wherein the method for driving the hot press actuator to perform nonlinear stress relaxation and depressurization control comprises: Analyzing the compression rate of the slab based on the feedback pressure and the displacement change rate with the timestamp mark in the molding state data stream, and judging to enter a solidification completion state when the feedback pressure is kept constant and the compression rate of the slab is continuously lower than a preset displacement creep threshold value; determining an initial pressure relief slope by utilizing the amplitude of the structural disturbance estimation parameter, and establishing a pressure relief pressure guiding reference which changes along with time by combining a pressure attenuation evolution criterion to construct a nonlinear stress relaxation depressurization control track; And regulating the opening degree of the servo valve according to the nonlinear stress relaxation depressurization control track, so that the actual pressure of the hot pressing executing mechanism is depressurized along the track.
9. A system for intelligently controlling a thermal compression molding process of a short fiber reinforced fiberboard according to claim 3, wherein the method for identifying characteristic frequency components by intensity peeling of energy distribution comprises: Marking a background energy plane determined by the characteristic parameters of the environmental noise in the three-dimensional distribution map, positioning an energy concentration center in a non-background area through a sliding search window, and executing local energy distribution position analysis based on centroid logic; The energy threshold value is determined according to the deviation degree between the background energy plane and the energy amplitude of the gravity center region by taking the gravity center coordinate as a reference, discrete energy components which are lower than the energy threshold value and are irrelevant to the gravity center coordinate in the three-dimensional distribution map are zeroed and erased by taking the energy threshold value as a judging condition, and high-energy clusters representing fiber damage characteristics are stripped; and mapping and projecting the high-energy cluster group to a frequency axis, and extracting the center frequency and the frequency bandwidth corresponding to the high-energy cluster group to identify characteristic frequency components.
10. The intelligent control system for hot press forming process of short fiber reinforced fiber board according to claim 5, wherein the method for extracting the pressure fluctuation component caused by the internal structure evolution comprises the following steps: Performing point-to-point association comparison and energy fusion on the structural disturbance parameters and pressure change information detected in the forming process in a sliding window to generate a cross-correlation coefficient sequence sliding along with sampling points; Performing slope analysis on the cross-correlation coefficient sequence, and judging the correlation strength of macroscopic pressure fluctuation and microstructure damage according to the slope change trend; and projecting the pressure change information detected in the forming process onto a time characteristic axis of the structural disturbance parameter by using the cross-correlation coefficient as a proportional gain coefficient, and stripping to obtain a pressure fluctuation component caused by internal structure evolution.

Description

Intelligent control system for hot press forming process of short fiber reinforced fiberboard Technical Field The invention relates to the technical field of intelligent control, in particular to an intelligent control system for a hot press forming process of a short fiber reinforced fiberboard. Background In the field of artificial board industry and composite material processing, the hot press forming process of short fiber reinforced fiber board is a complex physicochemical process involving rheology, heat transfer and material curing kinetics. The traditional control technology mainly relies on a preset pressure-temperature-time curve to carry out open-loop or semi-closed-loop control, and changes of macroscopic physical parameters are monitored through a pressure sensor and a displacement sensor, so that power output of a hydraulic driving system is adjusted. Along with the improvement of the fine production demand, a part of advanced scheme starts to introduce feedback control logic, and linear gain adjustment is performed on an actuating mechanism according to displacement creep rate or pressure feedback deviation so as to improve the density uniformity and mechanical property consistency of slab forming. However, the existing hot press control technology still has limitations in coping with real-time dynamic response of the evolution of the internal structure of the slab. Because the short fiber slab can generate complex fiber recombination, matrix flow and microstructure damage in the hot pressing process, macroscopic pressure signals often contain a large amount of mechanical vibration noise and system hysteresis characteristics, so that the existing feedback mechanism is difficult to accurately peel from disordered macroscopic pressure fluctuation and identify real disturbance caused by microscopic fiber skeleton damage or evolution. The information fault between the macroscopic monitoring and microscopic evolution ensures that the system cannot execute timely phase hedging compensation aiming at the transient energy release of an internal structure, so that transient stress generated by local structural damage in a plate blank cannot be effectively relaxed, microcracks or stress concentration areas are easily formed in a finished product, and quality defects such as layering burst, exceeding thickness expansion rate, macroscopic buckling deformation and the like of a fiber plate are induced when the stress concentration areas are serious. Disclosure of Invention The present invention has been made in view of the above-described problems occurring in the prior art. Therefore, the invention provides an intelligent control system for a hot press forming process of a short fiber reinforced fiberboard, which solves the problems that the pressure disturbance caused by the microstructure evolution in the interior of a slab is difficult to accurately identify and compensate in real time, and then the internal stress defect of the slab is caused. In order to solve the technical problems, the invention provides the following technical scheme: the invention provides an intelligent control system for a hot press forming process of a short fiber reinforced fiberboard, which comprises the following components: The acquisition module acquires slab multidimensional physical property characteristic parameters of the short fiber reinforced slab to be processed, and performs environmental noise suppression on the acoustic emission acquisition channel to obtain initial forming reference parameters; The damage sensing module captures stress wave pulses through a monitoring window which is dynamically opened and closed along with pressure load under the constraint of initial forming reference parameters, projects acoustic emission signals to a time-frequency cooperative domain, and extracts fiber damage variables through the intensity stripping of energy distribution; The disturbance module maps the fiber damage variable into a structural disturbance parameter of an internal structural evolution state of the short fiber reinforced slab, and performs coupling analysis on the structural disturbance parameter and pressure change information detected in the forming process to form a structural disturbance estimation parameter; The adjusting module maps the structural disturbance estimation parameters into synchronous heterogeneous phase compensation components, injects transient driving correction instructions which are counteracted with disturbance energy into the pressure control loop, and outputs a molding state data stream; and the pressure relief module is used for judging the solidification completion state based on the molding state data flow and driving the hot pressing executing mechanism to execute nonlinear stress relaxation and pressure reduction control according to the structural disturbance estimation parameters. Preferably, the method for obtaining the molding initial reference parameters comprises the f