Integrated control method for drying and impurity removal of bacterial rod based on multi-parameter cooperation

Abstract

The application relates to the field of agricultural material processing and automatic control technology, and discloses a bacteria rod drying and impurity removing integrated control method based on multi-parameter cooperation, which comprises the following steps: under a basic drying state, collecting the inlet and outlet air temperature and humidity, material bed pressure difference and fan frequency, calculating the surface dehydration rate derivative and airflow damping coefficient; when the set conditions are met, locking the inlet and outlet air channels and increasing the temperature, increasing the circulating fan speed to the peak frequency; after the preset time, opening the quick-opening bypass valve to build a negative pressure boundary, driving the airflow chopping baffle to alternately open and close to generate pulsed jet flow; during the period, calculating the material bed pressure difference change rate, and when the absolute value is lower than the steady-state threshold value, controlling the basic drying state to be restored. The technical scheme of extracting the surface dehydration rate derivative and the airflow damping coefficient and synchronously monitoring the attenuation trend of the two is adopted, so that the technical effect of accurately locking the critical window of the impurity adhesion force decrease is achieved.

Description

Technical Field

[0001] This invention relates to the field of agricultural material processing and automated control technology, specifically to an integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy. Background Technology

[0002] Before entering large-scale cultivation or processing, the substrate of mushroom spawn typically contains high initial moisture content, and its surface is often covered with a large amount of culture medium debris, dust, and other impurities. If these impurities are not cleaned, they will directly clog the air pores inside the substrate bed, severely weakening the ventilation and heat transfer efficiency of subsequent processes. In a suitable temperature and humidity drying environment, the accumulated impurities can easily become a breeding ground for miscellaneous microorganisms, thus reducing the overall yield of the spawn. Therefore, implementing efficient impurity removal simultaneously during the drying process is a necessary industrial step to ensure the quality of spawn processing and maintain smooth fluid flow within the system.

[0003] Currently, open-loop impurity removal systems based on time series are commonly used in industrial settings. Operators pre-set the running minutes for each stage of basic drying and forced-air impurity removal on the control panel. After the equipment starts, the main control program drives the fan to operate systematically, continuously inputting a large volume of hot air into the drying chamber. Some equipment also incorporates conventional electric dampers in the main air duct, using periodic opening and closing of mechanical structures to change the airflow direction or volume. This control architecture is highly streamlined, resulting in lower initial equipment development and deployment costs. For fixed production lines with relatively standard moisture content and a single type of impurity, this solution provides stable and continuous dehumidification power, and daily parameter debugging and maintenance are relatively intuitive and convenient.

[0004] Existing solutions reveal underlying control logic flaws when dealing with complex operating conditions. The moisture content of the mushroom substrate entering the furnace fluctuates significantly. Residual moisture between impurities and the substrate creates strong capillary adhesion. Fixed-time control cannot detect changes in this physical bonding force. The impurity removal program often starts blindly before the liquid bridge dissipates, at which point a constant high airflow is insufficient to cut off the interface adhesion. Directly creating flow field disturbances through high-frequency opening and closing of dampers causes the obstructed circulating airflow to quickly accumulate pressure locally. Traditional pipelines lack energy release paths, and the backlash from airflow shock waves easily triggers fan surges. Furthermore, flow field oscillations caused by mechanical movements severely interfere with the signal acquisition of differential pressure sensors. Faced with large fluctuations in noise, the control system cannot determine whether the pores inside the material bed are truly clear. This forces the continued use of a crude timed shutdown mechanism, frequently resulting in equipment running at full load and consuming power, or the program terminating prematurely before the resistance decreases. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an integrated control method for mushroom stick drying and impurity removal based on multi-parameter coordination. This method solves the problems of existing mushroom stick drying and impurity removal systems that rely on fixed timing, resulting in blind switching of operating conditions; the inability to destroy the capillary adsorption force of moisture on the surface of impurities by simply maintaining a constant large air volume; the easy occurrence of local air duct pressure buildup and fan surge due to mechanical disturbances; and the lack of a closed-loop feedback mechanism to determine the endpoint of impurity removal under complex flow field interference.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides an integrated control method for drying and removing impurities from mushroom spawn based on multi-parameter synergy, comprising the following steps:

[0008] The industrial programmable logic controller operates the basic control module to control the terminal execution equipment to be in the basic drying state, and collects status data in real time through the front-end sensing device according to the set system global sampling cycle.

[0009] The dynamic feature extraction module calculates the surface dehydration rate derivative and airflow damping coefficient in real time based on the collected state data;

[0010] The critical state determination module continuously monitors the surface dehydration rate derivative and the airflow damping coefficient, and confirms that the system has entered the phase change critical state window and outputs a program trigger signal when the set determination conditions are met.

[0011] The energy storage and excitation execution module responds to the program trigger signal, closes the air inlet and outlet channels and stops the dehumidification fan to control the system to force the temperature to rise, and at the same time controls the circulating fan to increase the speed to build up rotational inertia reserves.

[0012] The collaborative stripping control module controls the pneumatic quick-opening bypass valve to release airflow and build a negative pressure boundary, while controlling the mechanical chopper circuit to alternately cut off the circulating airflow to generate pulse jets;

[0013] The closed-loop feedback reset module monitors the bed resistance status parameters, resets the working posture of each terminal execution device after the differential pressure change rate converges, and reactivates the basic control module.

[0014] Preferably, the state data includes inlet air temperature, outlet air temperature, inlet air relative humidity, outlet air relative humidity, pressure difference across the material bed, and basic airflow velocity in the duct. The specific method for calculating the derivative of the surface dehydration rate is as follows: the inlet air relative humidity and outlet air relative humidity, combined with synchronously collected temperature data, are converted into inlet air absolute humidity and outlet air absolute humidity. The first derivative of the difference between the outlet air absolute humidity and the inlet air absolute humidity with respect to time is then calculated as the derivative of the surface dehydration rate, used to characterize the degree of attenuation of the intensity of moisture evaporation from the material surface.

[0015] Preferably, the specific method for calculating the airflow damping coefficient is as follows: divide the collected pressure difference across the material bed by the square of the basic airflow velocity of the duct; wherein, the basic airflow velocity of the duct is obtained by reading the actual operating frequency value of the circulating fan inverter and converting it with the cross-sectional area of ​​the duct. This coefficient is used to reflect the evolution of fluid resistance caused by material shrinkage due to water loss and changes in the porosity of the material bed.

[0016] Furthermore, before calculating the airflow damping coefficient, the system is configured with a lower limit amplitude protection logic for the basic airflow rate of the duct. When the basic airflow rate of the duct approaches the critical low value, the system automatically stops the calculation of the current cycle and calls the valid historical value of the previous sampling cycle to prevent overflow error in the underlying division operation.

[0017] Preferably, the specific conditions for satisfying the set judgment criteria include: the thermodynamic adhesion attenuation judgment condition being met, i.e., the surface dehydration rate derivative is less than a preset dehydration derivative threshold and the first derivative of the surface dehydration rate derivative with respect to time is less than 0; and the kinetic pore shrinkage judgment condition being met, i.e., the first derivative of the airflow damping coefficient with respect to time is less than 0. The system thus combines the characteristics of bed moisture evaporation and macroscopic resistance to identify state switching.

[0018] Furthermore, the system is confirmed to have entered the critical phase change state window if and only if the thermodynamic adhesion attenuation criterion and the dynamic pore shrinkage criterion are simultaneously maintained within multiple consecutive system global sampling cycles, so as to eliminate false triggering caused by transient fluctuations in the flow field.

[0019] Preferably, the specific operation of the control system for forced heating is as follows: output a zero-opening command to the air valves of the air inlet channel and the main exhaust duct, keep the pneumatic quick-opening bypass valve closed, control the frequency converter of the exhaust fan to output zero frequency, and adjust the output power of the proportional regulating heater to full load to increase the internal circulating air temperature, thereby increasing the internal heat energy reserve of residual moisture through sealed heating.

[0020] Furthermore, the specific operation of controlling the circulating fan to increase its speed and establish rotational inertia reserve is as follows: within a preset time period, the circulating fan is controlled to climb from the basic operating frequency to the preset peak frequency, and during this period, the louvered airflow chopper baffle in the mechanical chopper circuit is kept in a fully open state to establish the mechanical rotational inertia of the circulating flow field in advance, so as to prevent the subsequent physical cut-off operation of the airflow from causing the flow machine to surge.

[0021] Preferably, the specific operation for constructing a negative pressure boundary is as follows: A step-opening command is sent to the pneumatic quick-opening bypass valve in the dual-path exhaust valve assembly to switch it to the fully open state, and the output frequency of the exhaust fan inverter is simultaneously adjusted to the preset peak exhaust frequency. This operation utilizes the ambient pressure drop to cause localized vaporization and expansion of moisture, thereby weakening the physical bonding force between impurities and the material matrix.

[0022] Furthermore, the specific operation for generating pulse jets is as follows: a pulse control signal of a set frequency is sent to the servo motor in the mechanical chopper circuit to drive the louvered airflow chopper baffle to perform alternating cut-off and conduction actions, modulating the constant circulating airflow into pulse jets, and enhancing the surface scouring effect through periodic airflow pulsation.

[0023] Furthermore, during the alternating interruption of the circulating airflow, when the obstructed air pressure in a local duct exceeds the opening spring resistance of the passive mechanical pressure relief valve installed in the bypass pressure relief circuit, the pressurized gas flows back to the negative pressure side of the air inlet of the circulating fan through the bypass pressure relief circuit to buffer and release the transient local overpressure inside the duct.

[0024] Preferably, the specific operation for monitoring the bed resistance state parameters and calculating the differential pressure change rate is as follows: calling a low-pass filtering algorithm with a cutoff frequency lower than the mechanical chopper circuit operation frequency to smooth the collected historical differential pressure data sequence at both ends of the bed and extract the differential pressure baseline trend sequence; and performing differential time differentiation on the differential pressure baseline trend sequence to obtain the differential pressure change rate.

[0025] Furthermore, the specific condition for resetting the working posture of each terminal execution device after the differential pressure change rate converges is: the absolute value of the differential pressure change rate is lower than the preset differential pressure steady-state threshold within a continuous preset number of system global sampling cycles.

[0026] Furthermore, the specific operations for resetting the working posture of each terminal execution device include: sending a closing command to the pneumatic quick-opening bypass valve to stop the mechanical chopper circuit from operating and lock the airflow chopper baffle in the fully open position, and controlling the circulating fan and the dehumidifying fan to return to the basic operating frequency according to the set deceleration slope.

[0027] This invention also provides an integrated control system for drying and removing impurities from mushroom spawn based on multi-parameter coordination, including front-end sensing devices, terminal execution devices, and an industrial programmable logic controller (PLC). The PLC is configured to execute the steps of the above-described method. The PLC internally includes a basic control module, a dynamic feature extraction module, a critical state determination module, an energy storage and excitation execution module, a collaborative stripping control module, and a closed-loop feedback reset module.

[0028] The present invention also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the above method.

[0029] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0030] This invention provides an integrated control method for drying and removing impurities from mushroom spawn based on multi-parameter synergy. It has the following beneficial effects:

[0031] 1. This invention employs a technical solution that extracts the derivative of the surface dehydration rate and the airflow damping coefficient while simultaneously monitoring their attenuation trends. This achieves the technical effect of accurately locking the critical window for the decrease in impurity adhesion. Compared to the open-loop control scheme in existing technologies that relies on fixed time nodes, this invention solves the problem of timing errors caused by blindly switching impurity removal modes in traditional systems.

[0032] 2. This invention employs a pre-locked heating process to establish mechanical rotational inertia, followed by opening a bypass valve to create negative pressure and drive baffles to alternately intercept flow. This achieves the technical effect of enhancing impurity separation by utilizing the superposition of transient pressure drop and pulse jet. Compared to existing technologies that use a large volume of constant airflow for continuous purging, this invention overcomes the shortcomings of single pneumatic scouring, which is difficult to destroy capillary bridges, and the tendency of directly opening dampers to induce shock waves in the pipeline network.

[0033] 3. This invention employs a low-pass filter to remove pulsating components to obtain the pressure difference baseline trend, and triggers a working posture reset when the absolute value of the pressure difference change rate converges. This achieves the technical effect of online closed-loop quantization of the endpoint of the internal flow field reconstruction of the material bed. Compared with the existing technology that relies on empirical parameters or preset time to forcibly terminate the operation, this invention solves the problem of insufficient real-time resistance feedback in the later stage of impurity removal, which leads to ineffective drying energy consumption. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the system architecture according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the method flow according to an embodiment of the present invention;

[0036] Figure 3 This is a flowchart illustrating the basic control and parameter acquisition process in an embodiment of the present invention.

[0037] Figure 4 This is a flowchart illustrating the dynamic feature parameter calculation process according to an embodiment of the present invention.

[0038] Figure 5 This is a flowchart illustrating the phase transition critical state determination process according to an embodiment of the present invention.

[0039] Figure 6 This is a flowchart of the quasi-closed energy storage and kinetic energy pre-excitation magnetic control according to an embodiment of the present invention;

[0040] Figure 7 This is a schematic diagram illustrating the multi-field coupling collaborative stripping execution process and principle of an embodiment of the present invention;

[0041] Figure 8 This is a flowchart of the closed-loop feedback monitoring and state reset process according to an embodiment of the present invention;

[0042] Figure 9This is a timing diagram of the macroscopic operating state parameters of the system according to an embodiment of the present invention;

[0043] Figure 10 The diagram shows the system characteristic parameter determination and closed-loop feedback convergence process in an embodiment of the present invention, where (a) is the phase transition critical state determination process and (b) is the pressure difference signal filtering and steady-state convergence process.

[0044] Among them, 10 is the basic control module; 20 is the dynamic feature extraction module; 30 is the critical state determination module; 40 is the energy storage and excitation execution module; 50 is the collaborative stripping control module; and 60 is the closed-loop feedback reset module. Detailed Implementation

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Reference Figure 1 This invention provides an integrated control system for drying and removing impurities from mushroom sticks based on multi-parameter coordination, which may include: an industrial programmable logic controller, a front-end sensing device, and a terminal execution device.

[0047] The front-end sensing equipment is arranged inside the drying chamber and in the air duct structure, including inlet air temperature and humidity transmitters, outlet air temperature and humidity transmitters, and a differential pressure transmitter for monitoring the pressure difference across the material bed. The terminal actuators include a proportional heater, a servo proportional inlet valve, a circulating fan system, and a dehumidification exhaust fan system. The circulating fan system is driven by a circulating fan frequency converter. The dehumidification exhaust fan system is driven by an exhaust fan frequency converter.

[0048] A dual-path exhaust valve assembly is installed at the main exhaust duct of the drying chamber. This assembly consists of a servo-proportional exhaust valve and a pneumatic quick-opening bypass valve connected in parallel. The servo-proportional exhaust valve is used for opening adjustment during temperature and humidity tracking. The pneumatic quick-opening bypass valve is used to receive digital commands for state switching.

[0049] A mechanical chopper circuit is installed in the downstream duct of the circulating fan. The mechanical chopper circuit includes a servo motor and a louvered airflow chopper baffle driven by the servo motor. A bypass pressure relief circuit is provided on the local duct wall between the louvered airflow chopper baffle and the circulating fan outlet. A passive mechanical pressure relief valve is installed in the bypass pressure relief circuit, and its outlet end is connected to the negative pressure side of the circulating fan inlet to release stagnant stress inside the duct.

[0050] The industrial programmable logic controller is internally configured with a basic control module 10, a dynamic feature extraction module 20, a critical state determination module 30, an energy storage and excitation execution module 40, a collaborative stripping control module 50, and a closed-loop feedback reset module 60.

[0051] The basic control module 10 is used to execute closed-loop following logic for temperature and humidity, and outputs analog signals to adjust the heater power, servo proportional air inlet valve opening, and servo proportional air outlet valve opening.

[0052] The dynamic feature extraction module 20 is used to calculate the surface dehydration rate derivative and airflow damping coefficient based on real-time data collected by the front-end sensing device.

[0053] The critical state determination module 30 is used to determine the physical state of the system based on the trajectory change law of the surface dehydration rate derivative and the airflow damping coefficient, and output a program trigger signal.

[0054] The energy storage excitation execution module 40 is used to respond to the program trigger signal, output a full load command to the proportional adjustment heater, lock the drying chamber air valve passage, control the exhaust fan frequency converter to output zero frequency, and control the circulating fan frequency converter to execute the acceleration command.

[0055] The collaborative stripping control module 50 is used to output step opening commands to the pneumatic quick-opening bypass valve in the dual-path exhaust valve assembly and the exhaust fan frequency converter at a set time node, and at the same time drive the louvered airflow chopper baffle in the mechanical chopper circuit to perform periodic opening and closing actions.

[0056] The closed-loop feedback reset module 60 is used to calculate the differential pressure change rate based on the feedback data from the differential pressure transmitter, and to stop the mechanical chopper circuit from working after the calculated value reaches the steady-state boundary, control the relevant wind turbine frequency converter to execute the speed reduction command, and trigger the basic control module 10 to resume operation in advance.

[0057] Reference Figure 2 This invention provides an integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy, comprising the following steps:

[0058] S100, the industrial programmable logic controller runs the basic control module 10 to control the terminal execution equipment to be in the basic drying state, and collects status data in real time through the front-end sensing device according to the set sampling period;

[0059] S200, the dynamic feature extraction module 20 calculates the surface dehydration rate derivative and airflow damping coefficient in real time based on the collected state data;

[0060] S300, the critical state determination module 30 continuously monitors the surface dehydration rate derivative and the airflow damping coefficient, and triggers subsequent modules when the set determination conditions are met.

[0061] S400, the energy storage and excitation execution module 40 closes the air inlet and outlet channels and stops the dehumidification fan to control the system to force the temperature to rise, while controlling the circulating fan to increase the speed to build up rotational inertia reserves.

[0062] S500, the collaborative stripping control module 50 controls the pneumatic quick-opening bypass valve to release airflow and build a negative pressure boundary, while controlling the mechanical chopper circuit to alternately cut off the circulating airflow to generate pulse jets;

[0063] S600, the closed-loop feedback reset module 60 monitors the bed resistance status parameters, resets the working posture of each terminal execution device after the differential pressure change rate converges, and reactivates the basic control module 10.

[0064] The following section will provide a detailed explanation of each step in the integrated control method for drying and removing impurities from mushroom substrate based on multi-parameter synergy.

[0065] Reference Figure 3 In this embodiment, the initial control boundary is established and the underlying physical state parameters are obtained by running the basic control module 10. This process specifically includes the following operational stages:

[0066] S110, after the industrial programmable logic controller (PLC) is powered on and reset, the basic control module 10 performs initialization boundary configuration. Specifically, the basic control module 10 reads the drying target process curve pre-stored in its internal memory. The drying target process curve includes multiple time points set for a specific batch of mushroom logs, as well as the target temperature and target relative humidity values ​​corresponding to each time point. The basic control module 10 extracts the target reference value at the current time point and establishes a proportional-integral-derivative closed-loop following logic. The basic control module 10 defines the system's global sampling period. As a preferred approach, considering the high-frequency characteristics of subsequent airflow pulses and the response hysteresis boundary of the actuator, in order to satisfy the Shannon-Nyquist sampling theorem of digital signal processing and avoid spectral aliasing of high-frequency aerodynamic pulse signals during discretization acquisition, the system's global sampling period is [determined]. The value range is usually set between 10ms and 50ms to ensure that the control system has sufficient acquisition density and response margin for transient physical field changes.

[0067] During the normal temperature and humidity tracking process, the basic control module 10 periodically outputs analog control signals to adjust the output power of the proportional heater, the opening degree of the servo proportional air inlet valve, and the opening degree of the servo proportional exhaust valve in the dual-path exhaust valve assembly. During this stage, the pneumatic quick-opening bypass valve in the dual-path exhaust valve assembly remains closed. The basic control module 10 synchronously controls the circulating fan inverter and the exhaust fan inverter to operate at a constant speed at their base frequencies, driving the circulating fan and exhaust fan to provide stable circulation and exhaust airflow. The louvered airflow chopper baffle in the mechanical chopper circuit remains fully open. For the specific discretization calculation steps and parameter tuning rules of the proportional-integral-derivative closed-loop tracking logic, those skilled in the art can refer to existing industrial process control theories for configuration; the algorithm implementation is well-known in the field and will not be elaborated here.

[0068] S120, after the terminal execution device enters the basic drying state, the front-end sensing device follows the set system global sampling cycle. Perform synchronous data acquisition. This occurs at any point during system operation during the specific measurement phase. An inlet air temperature and humidity transmitter, positioned at the air inlet of the circulating air duct, synchronously collects and outputs the inlet air temperature and relative humidity. Similarly, an outlet air temperature and humidity transmitter, positioned at the air outlet, synchronously collects and outputs the outlet air temperature and relative humidity. Two pressure taps of a differential pressure transmitter are respectively located on the front windward side and the rear leeward side of the drying chamber's material bed. The differential pressure transmitter collects the static pressure difference signal from both ends and converts it into a digital air pressure differential. To prevent division by zero or overflow anomalies in subsequent feature calculations caused by electromagnetic interference or transient changes in sensors in industrial settings, the aforementioned acquired parameters can be processed by conventional moving average filtering before being written into the system register, in order to ensure the smoothness of the basic feature data and the completeness of the algorithm logic.

[0069] The industrial programmable logic controller (PLC) reads the actual operating frequency of the circulating fan inverter in real time via its internal data bus. The basic control module 10 calls pre-entered system duct cross-sectional geometry parameters and the circulating fan's factory performance flow rate curve, directly converting the actual operating frequency into the duct's basic airflow rate. From the perspective of fluid mechanics principles, under normal drying conditions where the total system resistance does not drastically change, the volumetric flow rate output by the fan is approximately proportional to its driving frequency. Combined with the known constant duct cross-sectional area, the current apparent velocity can be derived. Since directly measuring the physical wind speed in high-dust environments can easily lead to clogging and inaccuracy of Pitot tubes or thermal anemometers, using operating frequency to calculate wind speed usually provides relatively stable basic data support. Inlet air temperature, outlet air temperature, inlet air relative humidity, outlet air relative humidity, and air pressure difference are also considered. and the basic airflow rate of the duct Synchronously write to the register as the underlying representation data of the multidimensional physical state at the current moment.

[0070] Reference Figure 4 In this embodiment, a specific method for deriving core process parameters characterizing thermodynamic and aerodynamic states based on underlying acquired data is disclosed.

[0071] S210, the dynamic feature extraction module 20 retrieves the synchronously recorded inlet and outlet air humidity data from the system register and executes the program to solve for the derivative of the surface dehydration rate. Under a conventional drying environment with constant wind speed and a predetermined temperature, there is a mapping relationship between the amount of moisture carried away from the surface of the substrate by the circulating airflow and the humidity difference between the inlet and outlet air. To eliminate calculation errors caused by the slow drift of the ambient humidity over time, the dynamic feature extraction module 20 calculates the first derivative of the absolute humidity difference between the outlet and inlet air with respect to time to characterize the attenuation trend of the free water evaporation intensity on the surface of the mushroom substrate. The specific algebraic equation for the derivative of the surface dehydration rate is set as follows:

[0072] ;

[0073] in, This represents the derivative of the surface dehydration rate; Indicates time The absolute humidity of the air outlet; Indicates time The absolute humidity of the incoming air; This represents a time variable. Considering that the raw data collected by the front-end transmitter is typically relative humidity, the industrial programmable logic controller (PLC) has a pre-built conventional temperature and humidity conversion algorithm. This algorithm, combined with synchronously acquired temperature data, converts the relative humidity into absolute humidity, which includes a definite unit of moisture (e.g., grams per kilogram of dry air), before substituting it into the formula. In a practical computing environment, for discrete time series, the dynamic feature extraction module 20 calculates the first derivative by performing a backward difference operation on the humidity difference between the current system's global sampling period and the humidity difference between the previous system's global sampling period. For the specific implementation code of the discrete difference algorithm, those skilled in the art can refer to existing industrial digital signal processing methods; its basic code construction is well-known in the field and will not be elaborated upon here.

[0074] S220, accompanying the calculation of the aforementioned thermodynamic parameters, the dynamic feature extraction module 20 reads the differential pressure data uploaded by the differential pressure transmitter and the converted wind speed data, and executes the conversion logic for the airflow damping coefficient. From an aerodynamic perspective, the pressure loss generated when fluid passes through a porous packing medium usually conforms to the square law of resistance, that is, the pressure drop is positively correlated with the square of the apparent velocity. Coupled with the real-time detected pressure loss data and the square of the reference velocity, the calculation can reduce the impact of airflow disturbances caused by grid voltage fluctuations during the operation of the circulating fan, making the calculation results more concentrated in reflecting the physical characteristics of the material bed itself. The corresponding conversion formula is defined as follows:

[0075] ;

[0076] in, It represents the airflow damping coefficient, which is used to characterize the dynamic pore resistance changes inside the material bed caused by the accumulation of loose impurities on the surface or the shrinkage of the material itself due to water loss; Indicates time The air pressure difference between the front and rear ends of the material bed is measured in Pascals. Indicates time The corresponding basic airflow velocity in the duct is measured in meters per second. Based on dimensional analysis, this formula is derived from… In terms of physical dimensions, it is equivalent to the product of air fluid density and dimensionless local drag coefficient, and has definite aerodynamic practical significance.

[0077] As a preferred approach, to ensure the operational stability of the industrial programmable logic controller and prevent algorithmic logic dead zones, the system is internally configured with parameters for the basic airflow rate of the duct before the dynamic feature extraction module 20 performs the aforementioned division operation. The system employs a lower limit amplitude protection logic. When the detected basic airflow velocity in the duct approaches zero due to an external anomaly, the dynamic feature extraction module 20 automatically suspends the airflow damping coefficient calculation for the current cycle and uses the valid historical value from the previous sampling cycle as the current output. This fault-tolerant mechanism is used to avoid register overflow errors caused by the divisor approaching zero, thus maintaining the integrity of the calculation process. The result data obtained after the above calculations will be transmitted to the next level control layer in real time.

[0078] Reference Figure 5 In this embodiment, the core timing determination logic for triggering the system to perform multi-field collaborative noise removal is disclosed.

[0079] S310, Critical State Determination Module 30 reads the surface dehydration rate derivative output by Dynamic Feature Extraction Module 20. Thermodynamic adhesion attenuation is assessed. During the mushroom substrate drying process, as surface free water is gradually depleted, the drying process typically transitions from a constant-rate stage to a decreasing-rate stage. At this point, the capillary bridge force between impurity particles and the mushroom substrate decreases due to the reduction in moisture. To identify this physical state transition, the critical state determination module 30 calculates the time first derivative of the surface dehydration rate derivative in real time and combines it with a preset dehydration derivative threshold. A comprehensive evaluation will be conducted. The specific algebraic criteria are as follows:

[0080] ;

[0081] in, This represents the first derivative of the surface dehydration rate with respect to time; a calculated value less than zero indicates a continuously decreasing trend in the intensity of water evaporation. As a preferred approach, a dehydration derivative threshold is used. The value can be adjusted according to the specific material characteristics. In engineering implementation, the conventional practice is to conduct a standard weighing and drying calibration experiment on typical mushroom sticks of the same batch in advance, extract the average dehydration rate derivative of the constant-rate drying stage as a benchmark, and set 10% to 20% of this benchmark value as the dehydration derivative threshold. This tuning method helps to make the judgment conditions relatively objectively map the microscopic thermodynamic state of free water nearing depletion, and to some extent alleviates the problem of poor cross-batch adaptability caused by fixed thresholds.

[0082] S320, while performing the above thermodynamic determination, the critical state determination module 30 simultaneously reads the airflow damping coefficient. The system performs dynamic pore shrinkage determination. When impurities attached to the surface of the substrate lose water, the impurity particles undergo a certain degree of physical shrinkage due to internal moisture loss. This microscopic volume shrinkage often leads to a local expansion trend in the pores within the substrate bed. This physical change is reflected in the macroscopic aerodynamic parameters, specifically, the airflow damping coefficient exhibiting a local extreme value followed by a gradual decrease. The critical state determination module 30 identifies this state by monitoring the sign reversal characteristic of the time first derivative of the airflow damping coefficient. The specific algebraic determination conditions are as follows:

[0083] ;

[0084] in, This represents the first derivative of the airflow damping coefficient with respect to time. In the actual calculation logic, to reduce misjudgments caused by random noise from the sensor, the critical state determination module 30 is equipped with a time window discrimination mechanism. The system only confirms that the dynamic pore shrinkage determination condition is met when the aforementioned first derivative remains negative for multiple consecutive calculation cycles. The meeting of this condition indicates that the impurity body is basically in a dry and loose state, and its mechanical adhesion to the surface of the mushroom stick is relatively weak.

[0085] S330, within the system control cycle, the critical state determination module 30 continuously compares the above two determination conditions. The critical state determination module 30 determines the condition when the surface dehydration rate derivative satisfies the thermodynamic determination condition and the airflow damping coefficient satisfies the kinetic determination condition, and this dual satisfaction condition is maintained continuously. When the system maintains this state continuously within a global sampling period, the critical state determination module 30 confirms that the system has entered the phase transition critical state window. The number of consecutive confirmation periods is... The setting is used to filter transient disturbances in the system. Considering the hysteresis characteristics of thermodynamic and drag changes and the millisecond-level global sampling period of the system, those skilled in the art can set it to an integer between 100 and 300 according to the on-site anti-interference requirements.

[0086] Upon confirmation of entering the critical window, the critical state determination module 30 issues a program trigger signal. The industrial programmable logic controller (PLC) responds to this signal, suspending the operation of the basic control module 10, maintaining the current output state of the temperature and humidity ratio-integral-derivative closed-loop calculation module, and simultaneously activating the lower-level energy storage excitation execution module 40 to take over control of the terminal execution equipment. Through this command flow, the system can switch from a conventional drying state to a multi-field collaborative impurity removal state.

[0087] Reference Figure 6 In this embodiment, the main disclosed system is an operational procedure that establishes specific preconditions for the subsequent collaborative stripping process in order to address the inherent physical response delay of the mechanical actuator.

[0088] S410, after the critical state determination module 30 outputs a program trigger signal, the energy storage excitation execution module 40 takes over the corresponding control authority and executes the quasi-closed thermodynamic energy storage control logic. In specific implementation, the energy storage excitation execution module 40 outputs a zero-opening command to the servo proportional air inlet valve and the servo proportional exhaust valve in the dual-path exhaust valve assembly, while simultaneously keeping the pneumatic quick-opening bypass valve closed. The synchronous locking of these valves cuts off the airflow exchange between the drying chamber and the external environment, creating a relatively isolated quasi-closed space within the system. To prevent the exhaust fan from overloading due to pressure buildup caused by the main exhaust duct locking, the energy storage excitation execution module 40 synchronously controls the exhaust fan inverter to output zero frequency, causing the exhaust fan to enter a stop-and-standby state.

[0089] After the command to complete spatial isolation is issued, the energy storage excitation module 40 adjusts the output power of the proportional regulating heater to 100% full load. In this semi-closed environment, the full-load heating operation causes the temperature of the circulating air in the drying chamber to gradually rise. Since the air contains moisture evaporated from the material in the early stages, the closed heating process causes the air state to tend towards the saturation dew point under the current ambient pressure. This thermodynamic operation aims to increase the system enthalpy of the trace amount of moisture remaining at the interface between impurities and the substrate, allowing it to absorb more heat and provide corresponding internal energy reserves for subsequent local vaporization and expansion of moisture. Considering the safety operation limitations inside the drying chamber, the system is equipped with a temperature upper limit safety interlock logic during full-load heating. When the inlet air temperature and humidity transmitter detects that the ambient temperature reaches the preset material safety threshold, the heater will automatically reduce power or stop operation to prevent material damage or thermal runaway. The system is set to continue this energy storage process for a preset time period. .

[0090] S420, during the thermodynamic heating process, to reduce the risk of flow field turbulence caused by subsequent airflow physical cutoff operations, the energy storage excitation module 40 performs a pre-set time period... Internal synchronous implementation of kinetic energy pre-excitation control for the circulating flow field. The energy storage excitation execution module 40 sends an acceleration command to the circulating fan frequency converter, driving the circulating fan to gradually climb from the base operating frequency to the preset peak frequency. As a preferred method, this peak frequency is usually set to 90% to 100% of the rated operating frequency of the circulating fan to ensure that the system can obtain sufficient initial dynamic pressure. During this period, the louvered airflow chopper baffle in the mechanical chopper circuit remains fully open.

[0091] From the perspective of fluid machinery operation characteristics, the impeller of a large fan, due to its large mass, needs to overcome a certain mechanical inertia to accelerate from low frequency to high frequency. By performing the acceleration action in advance, the system converts the input electrical energy into the high-speed mechanical rotational inertia of the circulating fan rotor, and accumulates the corresponding airflow circulation kinetic energy within the sealed duct. When the fan operates at its peak frequency, its rotor maintains considerable rotational kinetic energy due to its own mass and high speed. When the louvered airflow chopper baffles perform high-frequency opening and closing actions during the subsequent impurity removal stage, causing a sharp fluctuation in the local resistance of the duct, the accumulated rotational inertia can, to a certain extent, suppress the sudden drop in speed and maintain a relatively stable air pressure output, thereby reducing the probability of the fan experiencing surge or stall due to transient overload. As a preferred method, the above-mentioned preset time period... The value of takes into account both the mechanical acceleration and ramp-up response time of the circulating fan and the heat transfer cycle required for closed heating, and is usually set between 30 and 120 seconds.

[0092] Reference Figure 7In this embodiment, the main disclosure is the specific physical process by which the system generates stripping force at both the microscopic and macroscopic levels to separate impurities through the coordinated operation of specific physical mechanisms.

[0093] S510, with the completion of the quasi-closed thermodynamic energy storage stage, the system transitions from the basic control state to the multi-field coupling collaborative stripping execution state. At this time, the collaborative stripping control module 50 outputs a step-opening command to the pneumatic quick-opening bypass valve in the dual-path exhaust fan assembly, and simultaneously wakes up and adjusts the output frequency of the exhaust fan inverter of the exhaust fan system to the preset peak exhaust frequency, driving the exhaust fan to perform high-speed suction. Driven by the pneumatic actuator, the pneumatic quick-opening bypass valve switches from a completely closed state to a fully open state within a short time (e.g., within 1 to 2 seconds). Since the air inlet valve is still in a closed state at this time, the air inside the drying chamber is rapidly drawn out, and the ambient static pressure drops accordingly, thus creating a transient negative pressure boundary within the drying chamber.

[0094] From the perspective of basic thermodynamics, a sudden drop in environmental pressure often disrupts the vapor pressure equilibrium of residual moisture at the microscopic interface. When the environmental pressure drops below the saturated vapor pressure of water at the current temperature, the boiling point of water decreases accordingly. Water that has accumulated a high system enthalpy during the quasi-closed energy storage phase is prone to local flash vaporization under this transient negative pressure environment. The transformation of water from liquid to gas phase is accompanied by significant volume expansion, which creates an outward microscopic physical thrust at the interface between impurities and the substrate. This microscopic physical thrust helps reduce the capillary bond strength between impurities and the material matrix, providing a prerequisite for interfacial desorption during subsequent macroscopic airflow scouring.

[0095] S520, while constructing the transient negative pressure boundary, the collaborative stripping control module 50 drives the mechanical chopper circuit located in the downstream duct of the circulating fan to generate the kinetic conditions required for macroscopic stripping. The specific action sequence is as follows: the collaborative stripping control module 50 sends a pulse control signal of a set frequency to the servo motor in the mechanical chopper circuit, causing the louvered airflow chopper baffle to perform alternating cut-off and conduction actions. This alternating action physically modulates the constant circulating airflow output by the circulating fan into a high-frequency pulse jet. When the pulsed airflow acts on the surface of the material bed, the resulting dynamic impact pressure... The following fluid dynamics formula can be used to characterize it:

[0096] ;

[0097] in, Indicates time The dynamic impact pressure of a pulsed airflow has a standard physical dimension of Pascal. This indicates the fluid density of the air inside the drying room, and its physical unit is kilograms per cubic meter. This indicates the basic apparent velocity provided by the circulating fan in the pre-excited state, and its physical unit is meters per second. The dimensionless cross-sectional modulation function related to the opening and closing action of the airflow chopper baffle is expressed, and its value varies periodically between 0 and 1. Dimensional analysis of this formula shows that the derivation result on the right side of the equation possesses complete pressure physical dimensions, indicating that the pulsed airflow macroscopically generates a periodically varying dynamic pressure impact force. This pulsed jet applies intermittent shear and purging stresses to impurities in a microscopically loosened state, thereby promoting the physical stripping of impurities from the material surface. As a preferred approach, the operating frequency of the airflow chopper baffle can be set to 2 Hz to 10 Hz, a frequency band that typically produces a mechanical impact effect matching the desorption of typical impurities. For the specific structural coordination between the mechanical linkage transmission and motor drive of the louver mechanism, those skilled in the art can refer to existing industrial damper modulation mechanisms for implementation; its basic transmission principle is well-known in the field and will not be elaborated upon here.

[0098] In the S530 process, during the aforementioned airflow chopping, when the louvered airflow chopper is in a fully closed position, the kinetic energy of the airflow output by the circulating fan is partially blocked. Considering that the circulating fan rotor has accumulated a relatively large moment of inertia during the pre-excitation stage, this forced flow interception often causes a rapid increase in air pressure in the local air duct between the louvered airflow chopper and the circulating fan outlet, forming an aerodynamic shock wave effect. To prevent transient stagnant stress feedback from causing surge or blade damage in the circulating fan, the system is equipped with a physical aerodynamic water hammer prevention mechanism.

[0099] In terms of specific structural implementation, a bypass pressure relief circuit is provided on the local duct wall between the louvered airflow chopper and the outlet of the circulating fan. The passive mechanical pressure relief valve configured in this bypass pressure relief circuit remains closed under normal conditions to maintain the system's airtightness. When the local air pressure rises due to the shock wave effect and exceeds the inherent opening spring resistance of the pressure relief valve, the pressurized gas will spontaneously flow back through the bypass pressure relief circuit and be discharged into the negative pressure side of the circulating fan's inlet. This design, which returns passively depressurized gas to the system interior, avoids the ineffective loss of internal system heat energy caused by the direct discharge of pulsating high-pressure gas into the external environment, and also acts as a pneumatic buffer, limiting the back pressure of the circulating fan within the designed operating range, thus helping to maintain the operational stability of the system's power mechanism during multi-field coupling and stripping operations.

[0100] Reference Figure 8 In this embodiment, the main disclosure is the convergence logic and specific operation sequence of the system after performing collaborative impurity removal, which identifies the steady-state limit of impurity stripping and safely restores the system to the normal basic drying operation state.

[0101] S610, as the collaborative stripping operation continues, impurities gradually detach from the surface of the substrate and are discharged with the airflow. This process directly leads to an expansion of the physical accumulation pores inside the substrate bed, and the local resistance of the fluid passing through the substrate bed also decreases. This change in microstructure and flow field resistance characteristics is macroscopically manifested as a decreasing trend in the differential pressure difference across the substrate bed detected by the differential pressure transmitter. To track the stripping process in real time, the closed-loop feedback reset module 60 extracts the historical data sequence uploaded by the differential pressure transmitter. Considering that the high-frequency pulsed airflow generated by the mechanical chopper circuit during the multi-field coupled collaborative stripping stage will cause severe periodic pulsations in the substrate bed pressure difference, directly performing differential differentiation on the original acquired data will cause severe numerical oscillations, which can easily lead to the failure of the subsequent steady-state determination logic. Therefore, before calculating the derivative, the closed-loop feedback reset module 60 first calls a preset low-pass filter algorithm to smooth the historical pressure difference data sequence. The cutoff frequency of this low-pass filter is set to a fundamental frequency band lower than the operating frequency of the airflow chopper baffle (e.g., 0.5 Hz to 1 Hz) to filter out high-frequency chopper pulsation components and extract a pressure difference baseline trend sequence that can truly characterize the overall flow resistance evolution of the material bed. Subsequently, based on the filtered pressure difference baseline trend sequence, the closed-loop feedback reset module 60 calculates the first derivative of the pressure difference with respect to time in real time, thereby obtaining the pressure difference change rate parameter reflecting the macroscopic impurity removal process. In actual industrial programmable logic controller operations, this derivative is usually approximated using a time discrete difference method. The specific calculation formula is expressed as follows:

[0102] ;

[0103] in, Indicates time The rate of change of pressure difference, whose physical unit is Pascal per second; Indicates time The baseline value of the pressure difference across the material bed after the above low-pass filtering process is expressed in Pascals. From a fluid dynamics perspective, it can be seen that when impurity desorption is nearing completion, the physical state of the material bed tends to stabilize, the downward trend of the pressure difference gradually slows down, and the value of the rate of change of pressure difference approaches zero.

[0104] S620: Considering the inherent turbulent fluctuations in the industrial flow field and the interference of quantization noise from the sensor itself, the differential derivative value calculated from a single sampling often exhibits transient fluctuations, which can easily lead to false triggering if directly applied. Therefore, the closed-loop feedback reset module 60 introduces a time window discrimination mechanism to comprehensively determine the absolute value of the differential pressure change rate. Its logical judgment conditions are set as follows:

[0105] ;

[0106] in, This is a preset steady-state threshold for differential pressure. When the absolute value of the rate of change of differential pressure is continuously... When the above inequality is continuously satisfied within the global sampling period of the system, the closed-loop feedback reset module 60 determines that the system has reached the impurity-free steady-state convergence boundary. As a preferred method, since the low-pass filter used in the early stage has an inherent signal delay, in order to ensure that the system obtains a truly physical steady state after filtering, the number of periods is confirmed. Typically, the value is taken as an integer between 50 and 200 to balance system response speed and anti-interference capability. Reaching this steady-state boundary indicates that the impurity stripping process on the bed surface is basically complete. If the high-energy-consuming multi-field coupling state is maintained, the resulting process gain is relatively limited. In addition, a preset differential pressure steady-state threshold is used. The value of is usually calibrated through an initial no-load benchmark test of the system. This involves recording the extreme value of the derivative of the background pressure difference fluctuation caused by the pulsed airflow in the drying chamber when there is no material, and taking 1.2 to 1.5 times this extreme value as 1.2 to 1.5 times the value of . The setting parameters. This tuning method based on background noise provides an objective reference for judging the reliability of the logic.

[0107] S630: Once the system confirms that the steady-state convergence boundary conditions are met, the closed-loop feedback reset module 60 intervenes to execute a smooth reset operation, aiming to reduce the transient impact of the operating mode switch on the power supply network and mechanical transmission components. During this process, the closed-loop feedback reset module 60 sends a closing command to the pneumatic quick-opening bypass valve in the dual-path exhaust valve assembly, releasing the transient negative pressure boundary inside the drying chamber by cutting off the pressure relief bypass branch. Along with the closing of the bypass valve, the system simultaneously sends a stop pulse to the mechanical chopper circuit, stopping the servo motor and locking the louvered airflow chopper baffle in its normal fully open conduction position, thereby terminating the generation of the high-frequency pulse jet. After the airflow disturbance source is eliminated, the closed-loop feedback reset module 60 simultaneously sends a smooth deceleration command to the circulating fan inverter and the exhaust fan inverter, driving the circulating fan and exhaust fan to recover from their previous peak frequency to their base operating frequency according to the set deceleration slope. To prevent pressure buildup and surge caused by the exhaust fan expelling air into the closed duct during speed reduction after the bypass valve closes, the closed-loop feedback reset module 60 outputs a reset completion signal simultaneously with the aforementioned speed reduction command, prematurely waking up the basic control module 10. The basic control module 10 then takes over control of the proportional heater, servo proportional air inlet valve, and servo proportional exhaust valve, reopening the servo proportional exhaust channel based on the basic closed-loop logic, allowing the system to smoothly return to the normal closed-loop drying state of temperature and humidity.

[0108] The following example illustrates the collaborative working process of the system's modules through a specific work scenario. This example uses the drying process of a batch of standard bagged mushroom logs as an example, setting the system's global sampling period to 20 milliseconds.

[0109] During the time period from t0 to t1, the system is in a basic drying state. For example... Figure 9 As shown, the basic control module 10 controls the heater and various air valves according to the process objectives. The frequency converters of the circulating fan and the exhaust fan maintain a basic operating frequency of 35 Hz. Front-end sensors collect temperature, humidity, and air pressure difference data. At this time, the system is in a constant-speed dehydration stage, and the relative humidity of the outlet air and the relative humidity of the inlet air maintain a fixed difference.

[0110] Approaching time t1, the free water on the surface of the mushroom substrate is almost completely consumed. For example... Figure 10 As shown in (a), the derivative of the surface dehydration rate calculated by the dynamic feature extraction module 20 decreases and crosses the preset dehydration derivative threshold line, with its first time derivative being less than zero. Simultaneously, the airflow damping coefficient is monitored to begin decreasing after reaching a local maximum. The critical state determination module 30 confirms that the above indicators meet the conditions within 200 consecutive sampling periods, determines that the system has entered the phase transition critical state window, and outputs a program trigger signal at time t1.

[0111] During the time period from t1 to t2, the system executes quasi-closed thermodynamic energy storage control. The energy storage excitation actuator module 40 takes over control, cutting off the air intake and exhaust channels. The dehumidification exhaust fan reduces its frequency to 0 Hz, the proportional regulating heater outputs full power, and the frequency of the circulating fan inverter increases to 50 Hz according to the slope. Figure 9 As shown, the temperature curve rises linearly during this stage, and the air inside the drying chamber approaches saturation. This operation lasts for 60 seconds, allowing internal energy to be accumulated for moisture flash evaporation and for the fan rotor to establish rotational inertia.

[0112] At time t2, the system transitions to a multi-field coupled collaborative stripping execution state. The collaborative stripping control module 50 controls the pneumatic quick-opening bypass valve to open, and the exhaust fan frequency converter jumps to 50 Hz. A transient negative pressure is generated inside the drying chamber. Simultaneously, the servo motor starts, driving the louvered airflow chopper baffle to perform opening and closing actions at a frequency of 5 Hz. The circulating airflow is modulated into a pulsed jet. During this period, the passive mechanical pressure relief valve opens intermittently to return the local overpressure gas.

[0113] Figure 10 (b) shows the fluid resistance variation during the time period from t2 to t3. Due to the influence of 5 Hz mechanical chopping, the raw differential pressure data exhibits high-frequency pulsation. The closed-loop feedback reset module 60 calls a low-pass filtering algorithm with a cutoff frequency of 1 Hz to process the data, obtaining a smoothly decreasing baseline trend sequence of differential pressure. After differential differentiation of this baseline sequence, the obtained rate of change of differential pressure converges to zero in the negative range.

[0114] At time t3, the absolute value of the differential pressure change rate is lower than the preset differential pressure steady-state threshold for 100 consecutive sampling periods. The closed-loop feedback reset module 60 confirms that the impurity removal process has reached the steady-state boundary, and the system enters the state reset phase.

[0115] After time t3, the closed-loop feedback reset module 60 closes the pneumatic quick-opening bypass valve, stops the servo motor, and locks the airflow chopper baffle in the fully open position. The frequency converters of the circulating fan and the exhaust fan return to 35 Hz according to the set slope. Figure 9 As shown, the operating frequency curve exhibits a smooth downward segment. Subsequently, the basic control module 10 resumes operation, and the system returns to the temperature and humidity following drying state dominated by the closed-loop PID algorithm.

[0116] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-parameter synergistic integrated control method for drying and removing impurities from mushroom logs, characterized in that: The method is applied to a programmable logic controller and includes the following steps: The control terminal executes the equipment in the basic drying state, and collects the inlet air temperature and humidity, outlet air temperature and humidity, pressure difference at both ends of the material bed and the actual operating frequency of the circulating fan according to the sampling cycle; The surface dehydration rate derivative is calculated based on the inlet air temperature and humidity and the outlet air temperature and humidity; the airflow damping coefficient is calculated based on the pressure difference between the two ends of the material bed and the actual operating frequency. The derivative of the surface dehydration rate and the airflow damping coefficient are monitored, and a program trigger signal is generated when the set judgment conditions are met. In response to the program trigger signal, the air inlet and outlet channels are locked and the heater is heated, and the circulating fan is accelerated to the peak frequency and maintained for a preset time period. After the preset time period ends, the pneumatic quick-opening bypass valve is opened to create a negative pressure boundary, while the airflow chopper baffle is driven to open and close alternately to generate a pulse jet. During the generation of the pulse jet, the rate of change of the pressure difference between the two ends of the material bed is calculated. When the absolute value of the rate of change of the pressure difference is lower than the preset steady-state threshold of the pressure difference, the terminal execution device is controlled to return to the basic drying state.

2. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 1, characterized in that, The steps for calculating the derivative of the surface dehydration rate and the airflow damping coefficient include: The inlet air temperature and humidity and the outlet air temperature and humidity are converted into inlet air absolute humidity and outlet air absolute humidity, and the first derivative of the difference between the outlet air absolute humidity and the inlet air absolute humidity with respect to time is calculated to obtain the derivative of the surface dehydration rate. The basic airflow velocity of the air duct is calculated based on the actual operating frequency and the cross-sectional area of ​​the air duct. The airflow damping coefficient is obtained by dividing the pressure difference between the two ends of the material bed by the square of the basic airflow velocity of the air duct.

3. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 2, characterized in that, During the calculation of the airflow damping coefficient, a lower limit amplitude protection logic is set for the basic airflow rate of the duct. When the basic airflow rate of the duct is detected to be lower than the set critical low value, the division calculation of the current sampling period is stopped and the airflow damping coefficient recorded in the previous sampling period is called.

4. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 1, characterized in that, The set judgment conditions include thermodynamic judgment conditions and kinetic judgment conditions; The thermodynamic determination condition is that the surface dehydration rate derivative is less than a preset dehydration derivative threshold, and the first derivative of the surface dehydration rate derivative with respect to time is less than 0. The dynamic determination condition is that the first derivative of the airflow damping coefficient with respect to time is less than 0.

5. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 4, characterized in that, When the thermodynamic determination condition and the kinetic determination condition are simultaneously maintained within a preset number of consecutive sampling periods, it is determined that the set determination condition is met and the program trigger signal is generated.

6. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 1, characterized in that, The operation of responding to the program trigger signal, locking the inlet and outlet air channels, controlling the heater to heat up, and increasing the speed of the circulating fan to the peak frequency and maintaining it for a preset time period includes: Output zero-opening command to the air valves of the air inlet channel and the main exhaust duct, keep the pneumatic quick-opening bypass valve in the terminal execution device closed, control the dehumidification fan to output zero frequency, and control the output power of the proportional adjustment heater to full load. The circulating fan is controlled to increase its speed to the peak frequency, and the airflow chopper baffle in the terminal execution device is kept in a fully open position to establish the mechanical rotational inertia of the circulating airflow inside the duct.

7. The integrated control method for drying and removing impurities from mushroom logs based on multi-parameter synergy as described in claim 1, characterized in that, After the preset time period ends, the operation of opening the pneumatic quick-opening bypass valve to create a negative pressure boundary, and simultaneously driving the airflow chopper baffle to alternately open and close to generate a pulse jet includes: A step opening command is output to the pneumatic quick-opening bypass valve at the main exhaust duct to switch the pneumatic quick-opening bypass valve to the fully open state, and the operating frequency of the dehumidification exhaust fan is simultaneously adjusted to the preset peak exhaust frequency to generate a transient pressure drop in the drying chamber. A pulse control signal of a set frequency is sent to the servo motor that drives the airflow chopper baffle, causing the airflow chopper baffle to periodically perform cut-off and conduction actions, generating the pulse jet that applies dynamic impact pressure to the surface of the material.

8. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 7, characterized in that, During the alternating opening and closing of the airflow chopper baffle, when the internal air pressure in a local duct exceeds the opening resistance of the passive mechanical pressure relief valve installed in the bypass pressure relief circuit due to the airflow interruption, the pressurized gas breaks through the passive mechanical pressure relief valve and flows back to the negative pressure side of the air inlet of the circulating fan through the bypass pressure relief circuit.

9. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 1, characterized in that, The operation of calculating the rate of change of the pressure difference across the two ends of the bed includes: A low-pass filtering algorithm with a set cutoff frequency is used to smooth the collected differential pressure data sequence at both ends of the material bed, and the differential pressure baseline trend sequence after filtering out high-frequency pulsation components is extracted. The set cutoff frequency is lower than the alternating opening and closing frequency of the airflow chopper baffle. The differential pressure trend sequence is differentiated with respect to time to obtain the differential pressure change rate.

10. The integrated control method for drying and removing impurities from mushroom sticks based on multi-parameter synergy as described in claim 1, characterized in that, The operation of controlling the terminal to restore the device to the basic drying state includes: Send a closing command to the pneumatic quick-opening bypass valve in the terminal execution device to stop driving the airflow chopper baffle and lock the airflow chopper baffle in the fully open position; The circulating fan and the dehumidifying exhaust fan in the terminal execution device are controlled to return to the basic operating frequency according to the set deceleration slope; The servo proportional exhaust valve controls the reopening of the main exhaust duct and restores closed-loop regulation of temperature and humidity.

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