A gradient pressure stewing system with multi-frequency ultrasonic wave auxiliary flavoring function

Abstract

This invention discloses a gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function, comprising a sealed stewing chamber, a heating and exhaust assembly, a controllable pressure regulating assembly, a frequency sweeping ultrasonic assembly, a food detection assembly, and a hysteresis adaptive controller. The food detection assembly acquires food thickness, seasoning liquid conductivity, turbidity, and ultrasonic echo. The hysteresis adaptive controller generates a flavor infusion hysteresis coefficient based on the real-time conductivity decrease rate and ultrasonic echo attenuation rate, and controls the chamber pressure to gradually increase to the target pressure in a fast-then-slow manner, forming a hyperbolic pressure-breathing fluctuation near the target pressure. Simultaneously, it controls the frequency sweeping ultrasound to shift from cavitation-type low frequency to penetration-type high frequency. When the flavor infusion hysteresis coefficient increases, the pressure rise slope is reduced, the breathing fluctuation time is prolonged, and the proportion of high-frequency sweeping is increased; when it remains below a threshold, the frequency sweeping ultrasound is stopped, and stable pressure cooking is initiated, improving the uniformity of flavor infusion in thick food pieces and reducing the risk of tissue damage.

Description

Technical Field

[0001] This invention relates to the field of intelligent cooking equipment technology, and more specifically to a gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function. Background Technology

[0002] With the development of home intelligent cooking equipment, central kitchen pre-prepared food processing equipment, and standardized catering processing equipment, stewing equipment has gradually evolved from traditional open-flame stew pots to electric pressure cookers, intelligent stew pots, pressure steaming equipment, and automated seasoning and processing equipment. Existing stewing equipment typically achieves food cooking through sealed heating, pressure increase and holding, timed pressure release, and temperature program control. Its basic principle is to use increased pressure to raise the boiling point of the liquid, accelerating the softening of the food at a higher temperature. The salt, sugar, amino acids, and spices in the seasoning liquid naturally diffuse to the surface and interior of the food due to the concentration difference. For meat, poultry, bean products, root vegetables, and pre-prepared semi-finished products, the stewing process not only requires the food to be cooked but also requires the seasoning components to penetrate the food relatively evenly, thereby forming a stable level of saltiness, flavor profile, and consistent taste.

[0003] While existing pressure cooking equipment can shorten cooking time, its control over the "flavor infusion process" remains relatively crude. Most equipment simply executes fixed heating, pressurizing, holding, and depressurizing programs based on preset menus, without assessing the real-time migration of seasoning liquid into the food. For thick cuts of meat, ingredients with tendons and membranes, dense bean products, or large root vegetables, seasoning components often concentrate on the surface first, leaving the interior under-seasoned. Extending the cooking time to improve internal flavor penetration can easily lead to excessive tenderness of the outer layer, shrinkage of meat fibers due to dehydration, cloudiness of the broth, loss of flavor compounds through volatilization, and damage to nutrients, making it difficult to achieve both even flavor infusion and tissue integrity.

[0004] To enhance mass transfer, some food processing techniques employ methods such as stirring, circulating spraying, vacuum marinating, or ultrasonic-assisted treatment. Ultrasonic waves, through cavitation, acoustic microfluidics, and mechanical disturbance, promote contact between the seasoning liquid and the food surface, improving penetration efficiency to a certain extent. However, existing ultrasonic-assisted flavoring methods typically use fixed frequencies, fixed power, or simple segmented outputs, focusing more on the marinating or cleaning stages and failing to precisely link with the pressure changes during pressure cooking, such as pressurization, holding, and depressurization. While low-frequency ultrasound has a strong cavitation effect, which helps open the surface channels of food, excessive or continuous use can easily cause surface damage and cloudiness in the broth. High-frequency ultrasound is gentler and beneficial for diffusion disturbances in micropores, but without the initial mass transfer driving force, it is difficult to effectively address the problem of insufficient flavor penetration into thicker food pieces. Therefore, single-frequency or simple frequency switching methods cannot meet the continuous changes in the food's flavor requirements, from surface disturbance to internal penetration.

[0005] Furthermore, existing pressure control methods mostly employ linear pressure increase, constant pressure holding, or one-time pressure release. Pressure changes primarily serve cooking efficiency and safe venting, without utilizing the liquid absorption, drainage, and retention effects generated by the pores and fiber gaps of the food under pressure changes. If the pressure rises too quickly, the surface tissue of the food may be rapidly compacted, reducing the ability of subsequent seasoning liquid to penetrate further. Excessive pressure fluctuations may cause food breakage, broth splashing, or deterioration of texture. Existing equipment lacks a control mechanism capable of adjusting the pressure increase slope, pressure fluctuation time, and ultrasonic frequency distribution in real time according to the difficulty of flavor absorption.

[0006] Meanwhile, existing intelligent stewing equipment has limited ability to sense the state of ingredients, typically only detecting temperature, pressure, or time, making it difficult to determine the migration rate of the seasoning liquid, the liquid absorption state inside the ingredients, and the degree of tissue relaxation. The conductivity of the seasoning liquid can reflect changes in soluble seasoning components such as salt to some extent; ultrasonic echo attenuation can reflect changes in the interface between the ingredients and the seasoning liquid, as well as changes in the internal tissue state; and turbidity changes can reflect changes in ingredient breakage or increased precipitates. However, existing equipment has not yet combined these parameters to establish control indicators characterizing the difficulty of the seasoning liquid continuing to migrate into the ingredients. Therefore, current technology still needs a gradient pressure stewing system that can comprehensively consider changes in conductivity, ultrasonic echo, and pressure control to dynamically determine the flavor absorption resistance, and accordingly adjust the pressure trajectory and sweeping ultrasonic output to improve the uniformity of flavor absorption inside the ingredients, shorten stewing time, and reduce the risk of tissue damage. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function, comprising a sealed stewing chamber, a heating and exhaust assembly, a controllable pressure regulating assembly, a sweeping ultrasonic assembly, a food detection assembly, and a hysteresis adaptive controller. The food detection assembly acquires food thickness, seasoning liquid conductivity, turbidity, and ultrasonic echo. The hysteresis adaptive controller generates a flavor infusion hysteresis coefficient based on the real-time conductivity decrease rate and ultrasonic echo attenuation rate, and controls the chamber pressure to gradually increase to the target pressure in a fast-then-slow manner, forming a hyperbolic pressure-breathing fluctuation near the target pressure. Simultaneously, it controls the sweeping ultrasonic frequency to shift from cavitation-type low frequency to penetration-type high frequency. When the flavor infusion hysteresis coefficient increases, the pressure rise slope is reduced, the breathing fluctuation time is prolonged, and the proportion of high-frequency sweeping is increased; when it remains below a threshold, the sweeping ultrasonic frequency is stopped, and stable pressure cooking is initiated, improving the uniformity of flavor infusion in thick food pieces and reducing the risk of tissue damage.

[0008] This application provides a gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function, including: a sealed stewing chamber, a heating and exhaust assembly, a controllable pressure regulating assembly, a sweeping ultrasonic assembly, a food detection assembly, and a resistance adaptive controller;

[0009] The food detection component includes a food thickness acquisition unit, a conductivity sensor, a turbidity sensor, and an ultrasonic echo transceiver unit, used to acquire food thickness, seasoning liquid conductivity, seasoning liquid turbidity, initial ultrasonic echo, and real-time ultrasonic echo.

[0010] The adaptive controller for retardation includes a flavor retardation coefficient generation module, a hyperbola cooperative trajectory generation module, and an adaptive correction module.

[0011] The flavor penetration resistance coefficient generation module is used to generate a flavor penetration resistance coefficient based on the real-time conductivity decrease rate and the ultrasonic echo attenuation rate, and the flavor penetration resistance coefficient increases as the real-time conductivity decrease rate and the ultrasonic echo attenuation rate decrease.

[0012] The hyperbolic collaborative trajectory generation module is used to control the controllable pressure regulating component and the frequency sweeping ultrasound component according to the ingestion blockage coefficient, so that the intracavitary pressure rises to the target pressure in a hyperbolic asymptotic manner with a fast initial pressure followed by a slow pressure later, and forms a hyperbolic pressure respiratory fluctuation around the target pressure. At the same time, the frequency sweeping ultrasound component migrates from cavitation type low frequency to permeation type high frequency in a continuous frequency sweep or multi-transducer overlapping switching mode. The hyperbolic pressure respiratory fluctuation is a periodic pressure rise and fall around the target pressure, and both the pressure rise slope and the pressure fall slope change with a fast initial pressure followed by a slow pressure later.

[0013] The adaptive correction module is used to reduce the pressure ramp slope, prolong the hyperbolic pressure-respiratory fluctuation time and increase the proportion of high-frequency sweep when the ingestion resistance coefficient increases relative to the previous sampling cycle, and to stop the sweep ultrasound and switch to the stable pressure maturation state when the ingestion resistance coefficient is lower than the preset threshold within a preset number of consecutive sampling cycles.

[0014] Preferably, the pressure control trajectory generated by the hyperbolic collaborative trajectory generation module includes an asymptotic pressure increase segment and a respiratory fluctuation segment; in the asymptotic pressure increase segment, the rate of pressure increase in the cavity gradually decreases with the increase of running time, so that the pressure gradually approaches the target pressure in a way that avoids pressure overshoot; in the respiratory fluctuation segment, the cavity pressure rises and falls periodically around the target pressure, and the pressure increase slope and pressure decrease slope in each cycle change from fast at the beginning to slow at the end.

[0015] Preferably, the frequency-sweeping ultrasound component includes a broadband transducer capable of covering 20–500 kHz, or includes a low-frequency cavitation transducer with an operating frequency of 20–45 kHz, a mid-frequency mass transfer transducer with an operating frequency of 45–120 kHz, and a high-frequency penetrating transducer with an operating frequency of 120–500 kHz. The hyperbolic frequency sweep method is as follows: in the initial stage of the frequency sweep, the residence time in the cavitation-type low-frequency region of 20–45 kHz is relatively short and the frequency sweep change rate is relatively large; in the middle stage of the frequency sweep, it passes through the mass transfer transition frequency region of 45–120 kHz; in the later stage of the frequency sweep, the residence time in the penetrating high-frequency region of 120–500 kHz increases and the frequency sweep change rate decreases, so that the frequency-sweeping ultrasound migrates from the cavitation-type low-frequency region through the mass transfer transition frequency region to the penetrating high-frequency region.

[0016] Preferably, the flavor penetration resistance coefficient generation module uses the rate of change between the initial conductivity and the real-time conductivity of the seasoning liquid as a measure of the migration speed of the seasoning components, and uses the attenuation rate between the initial ultrasonic echo and the real-time ultrasonic echo as a measure of liquid absorption and tissue relaxation inside the food. The flavor penetration resistance coefficient generation module normalizes the measure of the migration speed of the seasoning components and the measure of liquid absorption and tissue relaxation inside the food, and performs reverse weighted fusion on the normalized measure of the migration speed of the seasoning components and the measure of liquid absorption and tissue relaxation inside the food to generate the flavor penetration resistance coefficient.

[0017] Preferably, when the ingestion resistance coefficient increases relative to the previous sampling period, the adaptive correction module performs at least one of the following control actions: reducing the pressure increase per unit time of the controllable pressure regulating component, reducing the frequency of hyperbolic pressure respiratory fluctuations and prolonging a single respiratory cycle, increasing the residence time of the sweep ultrasound in the permeable high-frequency region, reducing the output power in the cavitation low-frequency region, and increasing the pressure holding time near the target pressure.

[0018] Preferably, the controllable pressure regulating component includes a pressure boosting unit, a proportional pressure relief valve, and a pressure buffer chamber; the pressure boosting unit is used to form an asymptotic pressure increase segment, the proportional pressure relief valve is used to form a hyperbolic pressure reduction process in the respiratory fluctuation segment according to the pressure relief opening signal output by the hysteresis adaptive controller, and the pressure buffer chamber is used to weaken pressure abrupt changes, so that the pressure rise and fall amplitude in the respiratory fluctuation segment is kept within a preset proportional range of the target pressure.

[0019] Preferably, the ultrasonic echo transceiver unit emits probe ultrasound during the interval when the sweep frequency ultrasonic component stops outputting, and receives echo signals from the interface between the food and the seasoning liquid and the interface between the internal tissues of the food, so as to avoid interference of the sweep frequency ultrasonic output signal with the calculation of the flavor absorption resistance coefficient.

[0020] Preferably, the adaptive controller further includes a food thickness correction module; the food thickness correction module is used to correct the target pressure, hyperbolic asymptotic pressure rise time and high-frequency sweep ratio according to the food thickness; the greater the food thickness, the longer the hyperbolic pressure respiratory fluctuation time near the target pressure, and the higher the high-frequency sweep ratio.

[0021] Preferably, the damping adaptive controller further includes a tissue protection module; the tissue protection module judges the risk of food tissue damage based on ultrasonic echo mutations, abnormal conductivity fluctuations and / or abnormal increases in turbidity of the seasoning liquid; when the risk of food tissue damage exceeds a preset risk threshold, it restricts cavitation-type low-frequency output, reduces the amplitude of hyperbolic pressure respiration fluctuations and / or prolongs the hyperbolic pressure respiration fluctuation period.

[0022] Preferably, the pressure stabilization and maturation state is as follows: stop the frequency sweeping ultrasound or only retain the low-power penetrating high-frequency ultrasound, control the intracavitary pressure to maintain within the maturation target pressure range, and determine the end of the pressure stabilization and maturation process based on the slowing down of real-time conductivity changes, the stabilization of ultrasound echo attenuation, and the flavor penetration resistance coefficient being lower than a preset threshold.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] (1) This invention uses a food ingredient detection component to acquire real-time changes in the conductivity of the seasoning liquid and changes in the attenuation of the ultrasonic echo. A flavor penetration resistance coefficient generation module generates a flavor penetration resistance coefficient that characterizes the difficulty of the seasoning liquid continuing to migrate into the food, so that the system no longer relies solely on a fixed time or fixed pressure program for stewing. When a decrease in the rate of decrease in conductivity and the rate of decrease in echo attenuation are detected, it indicates that the migration of the seasoning liquid into the interior is hindered. The system then promotes the continued entry of the seasoning liquid into the pores and fiber gaps of the food by extending the hyperbolic pressure breathing fluctuation time and increasing the proportion of high-frequency sweep frequency, thereby improving the problem of flavor penetration on the surface of thick meat, bean products and root vegetables while the core is bland.

[0025] (2) This invention employs a hyperbolic asymptotic pressure-increasing method with a fast initial pressure followed by a slow pressure increase. This allows the intracavitary pressure to rapidly establish mass transfer driving force in the initial stage, and then gradually approach the target pressure in the later stage, avoiding the sudden compaction or damage to the surface of the food due to linear rapid pressure increase. At the same time, a hyperbolic pressure breathing fluctuation is formed near the target pressure, causing the pores inside the food to produce a gentle liquid absorption and retention effect during the small pressure increase and decrease process. The frequency sweeping ultrasound gradually shifts from cavitation-type low frequency to penetration-type high frequency, reducing the risk of surface breakage, soup turbidity, and fiber breakage caused by long-term low-frequency cavitation, making the flavor enhancement process more gradual, continuous, and controllable.

[0026] (3) The present invention is equipped with an adaptive correction module, an ingredient thickness correction module, and a tissue protection module. It can dynamically correct the target pressure, asymptotic pressure rise time, pressure breathing fluctuation period, and high-frequency sweep ratio based on information such as ingredient thickness, changes in flavor penetration resistance coefficient, abnormal turbidity of seasoning liquid, abnormal fluctuation of conductivity, and abrupt changes in ultrasonic echo. For thicker or denser ingredients, the system automatically extends the breathing fluctuation time and increases the proportion of penetrating high-frequency action; for fragile ingredients or situations where there is a risk of tissue damage, it limits the cavitation low-frequency output and reduces the pressure fluctuation amplitude, thereby improving the consistency of stewing results for different batches and types of ingredients. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall working connection of a gradient pressure stewing system with multi-frequency ultrasonic assisted flavor infusion function.

[0028] Figure 2 This is a schematic diagram of the structure of the food detection component of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the sealed stewing chamber, heating and exhaust assembly, controllable pressure regulating assembly, and frequency sweeping ultrasonic assembly of the present invention;

[0030] Figure 4 This is the functional block diagram of the damping adaptive controller of the present invention. Detailed Implementation

[0031] Those skilled in the art will understand that, in order to make the above-mentioned objects, features, and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1 This application provides a gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function, including: a sealed stewing chamber, a heating and exhaust assembly, a controllable pressure regulating assembly, a sweeping ultrasonic assembly, a food detection assembly, and a resistance adaptive controller;

[0032] This embodiment provides a gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function, such as... Figure 3 As shown, it includes a sealed stewing chamber 1, a heating and exhaust assembly 2, a controllable pressure regulating assembly 3, a sweeping ultrasonic assembly 4, a food detection assembly 5, and a resistance adaptive controller 6.

[0033] The sealed stewing chamber 1 is used to contain the ingredients to be stewed and the seasoning liquid. The sealed stewing chamber 1 includes a chamber body 11, a sealed chamber cover 12, an inner pot 13, and a sealing ring 14. The inner pot 13 is located inside the chamber body 11 and is made of food-grade stainless steel or corrosion-resistant ceramic-coated metal material to adapt to the long-term stewing environment of seasoning liquids containing salt, acid, sugar, and spices. The sealed chamber cover 12 is connected to the chamber body 11 by a locking structure or a screw-locking structure. The sealing ring 14 is located between the opening edge of the sealed chamber cover 12 and the inner pot 13 to maintain the seal inside the chamber during heating and pressurization. The sealed chamber cover 12 is provided with an exhaust port, a pressure detection interface, a pressure relief interface, and an ultrasonic echo detection interface. The side wall or bottom of the chamber body 11 is provided with a heating installation area and an ultrasonic transducer installation area.

[0034] The heating and exhaust assembly 2 includes a bottom heating plate 21, a side wall auxiliary heating element 22, an exhaust channel 23, and an electrically controlled exhaust valve 24. The bottom heating plate 21 is located at the bottom of the sealed stewing chamber 1 and is used to transfer the main heat to the inner pot 13. The side wall auxiliary heating element 22 is arranged circumferentially along the side wall of the chamber body 11 to reduce the temperature difference between the upper and lower parts of the chamber and the temperature lag in the side wall area. The exhaust channel 23 is connected to the upper part of the sealed stewing chamber 1, and the electrically controlled exhaust valve 24 is located on the exhaust channel 23. After the system is started, the damping adaptive controller 6 first controls the bottom heating plate 21 and the side wall auxiliary heating element 22 to operate at low to medium power, so that the air and some water vapor in the chamber are discharged through the exhaust channel 23. When the temperature in the chamber reaches the preset exhaust end temperature or the exhaust time reaches the set time, the electrically controlled exhaust valve 24 closes, so that the sealed stewing chamber 1 enters a pressurized state.

[0035] The controllable pressure regulating component 3 includes a pressure boosting unit 31, a proportional pressure relief valve 32, a pressure buffer chamber 33, a safety pressure relief valve 34, and a pressure sensor 35. The pressure boosting unit 31 can be formed by the steam pressure generated by the heating exhaust component 2, and may further include a miniature pressure-resistant air pump or steam generator, used to increase the pressure inside the sealed stewing chamber 1. The proportional pressure relief valve 32 is located at the pressure relief port on the sealed chamber cover 12 or the upper part of the chamber, and is electrically connected to the damping adaptive controller 6, used to achieve continuously adjustable pressure relief according to the pressure relief opening signal output by the controller. The pressure buffer chamber 33 is located between the proportional pressure relief valve 32 and the exhaust outlet, used to absorb short-term pressure surges, preventing violent pressure relief, soup splashing, or food tumbling during pressure fluctuations. The safety pressure relief valve 34 is a mechanical or electromechanical composite pressure limiting valve, automatically releasing pressure when the pressure inside the chamber exceeds the safe upper limit. The pressure sensor 35 is used to collect the pressure inside the chamber in real time and feed the pressure signal back to the damping adaptive controller 6.

[0036] The sweeping ultrasonic component 4 includes a low-frequency cavitation transducer 41, a mid-frequency mass transfer transducer 42, a high-frequency permeation transducer 43, and an ultrasonic drive power supply 44. In one embodiment, the low-frequency cavitation transducer 41 is disposed at the bottom or lower side wall of the sealed stewing chamber 1, and operates at a frequency of 20–45 kHz. It is used to generate moderate cavitation disturbance in the early stage of stewing, causing bubbles attached to the surface of the food to detach and creating reversible micro-perturbation channels. The mid-frequency mass transfer transducer 42 is disposed on the side wall of the sealed stewing chamber 1, and operates at a frequency of 45–120 kHz. It is used to generate acoustic microflow and weaken the low-concentration boundary layer of seasoning liquid on the surface of the food. The high-frequency permeation transducer 43 is disposed inside the sealed chamber cover 12 or on the upper side wall of the chamber, and operates at a frequency of 120–500 kHz. It is used to generate fine sound pressure disturbance in the pores and fiber gaps inside the food, promoting the diffusion of seasoning liquid into the interior. The ultrasonic drive power supply 44 is connected to each transducer and controlled by the hysteresis adaptive controller 6 to achieve continuous frequency sweep or multiple transducer overlapping switching.

[0037] In another embodiment, the sweep frequency ultrasonic component 4 may also include one or more broadband transducers capable of covering 20 to 500 kHz. The broadband transducers are located at the bottom, side walls and / or cover of the sealed stewing chamber 1. The output frequency, power and duty cycle are adjusted by the ultrasonic drive power supply 44 so that the ultrasonic action gradually shifts from the cavitation type low frequency region through the mass transfer transition frequency region to the penetration type high frequency region.

[0038] The food ingredient detection component 5 includes a food ingredient thickness acquisition unit 51, a conductivity sensor 52, a turbidity sensor 53, and an ultrasonic echo transceiver unit 54. The food ingredient thickness acquisition unit 51 can be a distance sensor located below the cavity cover, a pressure contact thickness gauge, or an image recognition-based thickness estimation unit, used to acquire the average or maximum thickness of the food ingredient. The conductivity sensor 52 is located in the lower part of the sealed stewing cavity 1 or within the seasoning liquid circulation detection channel, used to detect the real-time conductivity of the seasoning liquid, thereby reflecting the changing trend of soluble seasoning components such as salt. The turbidity sensor 53 is located in the seasoning liquid flow area, used to detect the increase in suspended particles, protein precipitates, or food debris in the broth, to determine the risk of food tissue damage. The ultrasonic echo transceiver unit 54 includes a probe ultrasonic transmitter and an echo receiver, preferably located on the side wall of the cavity or inside the cavity cover. It emits probe ultrasonic waves during the gap when the sweep frequency ultrasonic component 4 stops outputting, and receives echo signals from the interface between the food ingredient and the seasoning liquid, as well as the interface between the internal tissues of the food ingredient.

[0039] The hysteresis adaptive controller 6, such as Figure 4The system includes a data acquisition module 61, a flavor penetration resistance coefficient generation module 62, a hyperbola collaborative trajectory generation module 63, an adaptive correction module 64, a food thickness correction module 65, a tissue protection module 66, and an execution control module 67. The data acquisition module 61 is connected to a pressure sensor 35, a food thickness acquisition unit 51, a conductivity sensor 52, a turbidity sensor 53, and an ultrasonic echo transceiver unit 54, respectively, and is used to acquire food thickness, intracavitary pressure, seasoning liquid conductivity, seasoning liquid turbidity, initial ultrasonic echo, and real-time ultrasonic echo. The flavor penetration resistance coefficient generation module 62 generates a flavor penetration resistance coefficient based on the real-time conductivity decrease rate and the ultrasonic echo attenuation rate; when the real-time conductivity decreases and the ultrasonic echo attenuation rate decreases, it indicates that it becomes more difficult for the seasoning liquid to continue migrating into the food, and the flavor penetration resistance coefficient increases accordingly.

[0040] The hyperbolic collaborative trajectory generation module 63 generates a pressure control trajectory and a swept-frequency ultrasonic control trajectory based on the flavor absorption resistance coefficient. Specifically, during the gradual pressurization phase, the pressurization unit 31 and the heating exhaust assembly 2 are controlled to raise the intracavitary pressure to the target pressure in a hyperbolic asymptotic manner, with a faster initial pressurization rate to quickly establish the mass transfer driving force; the pressurization rate gradually decreases in the later stage to avoid pressure overshoot and rapid compaction of the food surface. Near the target pressure, the hyperbolic collaborative trajectory generation module 63 controls the proportional pressure relief valve 32 and the pressurization unit 31 to form a hyperbolic pressure breathing fluctuation, that is, the intracavitary pressure rises and falls slightly and periodically around the target pressure, and the pressurization slope and depressurization slope in each cycle change with a faster initial slope and slower depressurization rate, so that the pores of the food produce a liquid absorption and retention effect under gentle pressure fluctuations.

[0041] Meanwhile, the hyperbolic collaborative trajectory generation module 63 controls the frequency sweeping ultrasonic component 4 to perform hyperbolic frequency sweep output. In the initial stage of the frequency sweep, the ultrasonic frequency is located in the cavitation-type low-frequency region of 20-45kHz, with a short residence time and a large frequency sweep change rate, which is used to form short-term surface disturbances; in the middle stage of the frequency sweep, the ultrasonic frequency passes through the mass transfer transition frequency region of 45-120kHz, which is used to enhance the exchange of seasoning liquid near the surface of the food; in the later stage of the frequency sweep, the ultrasonic frequency migrates to the penetrating high-frequency region of 120-500kHz, with an increased residence time and a decreased frequency sweep change rate, which is used to promote the diffusion of seasoning liquid along the micropores and fiber gaps inside the food.

[0042] The adaptive correction module 64 adjusts subsequent control parameters based on the changing trend of the flavor penetration resistance coefficient. When the flavor penetration resistance coefficient increases relative to the previous sampling period, the adaptive correction module 64 reduces the pressure ramp slope in subsequent control periods, prolongs the hyperbolic pressure-respiratory fluctuation time, and increases the proportion of the sweep frequency ultrasound in the permeable high-frequency region. When the flavor penetration resistance coefficient is lower than the preset threshold within a preset number of consecutive sampling periods, it indicates that the resistance to the continued migration of the seasoning liquid into the food is small or the flavor penetration process tends to be stable. The adaptive correction module 64 controls the sweep frequency ultrasound component 4 to stop the sweep frequency output and puts the system into a stable pressure cooking state.

[0043] The food thickness correction module 65 is used to correct the target pressure, hyperbolic asymptotic pressure ramp duration, and high-frequency sweep ratio based on the food thickness. For thicker beef chunks, pig trotters, chicken legs, or root vegetables, the food thickness correction module 65 increases the hyperbolic pressure respiratory fluctuation time near the target pressure and increases the residence ratio in the osmotic high-frequency region; for thinner or fragile foods, it reduces the target pressure, shortens the respiratory fluctuation time, or limits low-frequency cavitation output.

[0044] The tissue protection module 66 is used to determine the risk of food tissue damage based on abrupt changes in ultrasonic echo, abnormal fluctuations in conductivity, and / or an abnormal increase in the turbidity of the seasoning liquid. When the turbidity sensor 53 detects a rapid increase in the turbidity of the seasoning liquid, or when the ultrasonic echo transceiver unit 54 detects a sudden change in echo attenuation, the tissue protection module 66 determines that the food may experience surface breakage, fiber breakage, or increased protein precipitation, thereby limiting the cavitation-type low-frequency output, reducing the amplitude of hyperbolic pressure respiration fluctuations, and / or extending the hyperbolic pressure respiration fluctuation period. The execution control module 67 is connected to the heating exhaust assembly 2, the controllable pressure regulating assembly 3, and the frequency sweeping ultrasonic assembly 4, respectively, and is used to convert the control parameters generated by the hyperbolic cooperative trajectory generation module 63 and the adaptive correction module 64 into heating power signals, proportional pressure relief valve opening signals, pressurization control signals, ultrasonic frequency signals, ultrasonic power signals, and ultrasonic duty cycle signals.

[0045] During the operation of this embodiment, the overall structure is as follows: Figure 2As shown, after the user places the ingredients and seasoning liquid into the sealed stewing chamber 1, the system first acquires the thickness of the ingredients, the initial conductivity of the seasoning liquid, and the initial ultrasonic echo. Then, it performs heating and exhaust to expel air from the chamber and establish an initial thermal environment. Next, it enters a hyperbolic asymptotic pressure ramp-up stage and a hyperbolic pressure respiration fluctuation stage, while the frequency sweeping ultrasonic component 4 gradually migrates from cavitation-type low frequency to penetration-type high frequency. Throughout the process, the hindrance adaptive controller 6 continuously calculates the flavor penetration hindrance coefficient and dynamically adjusts the pressure ramp-up slope, respiration fluctuation time, and high-frequency sweep ratio based on this coefficient. When the flavor penetration hindrance coefficient continuously falls below a preset threshold, the system stops the frequency sweeping ultrasound or retains only low-power penetration-type high-frequency ultrasound, controlling the pressure inside the chamber to remain within the target cooking pressure range, thus completing the stable pressure cooking. Through the above structure and control method, this embodiment enables the migration process of the seasoning liquid into the ingredients to form a closed-loop coordination with pressure changes, ultrasonic frequency sweeping, and ingredient status feedback, thereby improving the uniformity of flavor penetration in thick ingredients, reducing tissue damage caused by excessive low-frequency cavitation or rapid pressure ramp-up, and improving the cooking consistency of different batches of ingredients. The food ingredient detection component includes a food ingredient thickness acquisition unit, a conductivity sensor, a turbidity sensor, and an ultrasonic echo transceiver unit, used to acquire food ingredient thickness, seasoning liquid conductivity, seasoning liquid turbidity, initial ultrasonic echo, and real-time ultrasonic echo. In this embodiment, the food ingredient detection component 5 is disposed in the sealed stewing chamber 1 and its associated detection channel, used to acquire food ingredient thickness, seasoning liquid conductivity, seasoning liquid turbidity, initial ultrasonic echo, and real-time ultrasonic echo before stewing begins and during stewing. The food ingredient detection component 5 includes a food ingredient thickness acquisition unit 51, a conductivity sensor 52, a turbidity sensor 53, and an ultrasonic echo transceiver unit 54, each detection unit being connected to the data acquisition module of the resistance adaptive controller 6.

[0046] The food thickness acquisition unit 51 is used to acquire the thickness information of the food to be stewed. The thickness information can be the maximum thickness, average thickness, or thickness of the main heated area of ​​the food. In one embodiment, the food thickness acquisition unit 51 includes a temperature-resistant distance sensor disposed inside the sealed cavity cover and a support reference surface disposed at the bottom of the sealed stewing cavity. After the food to be stewed is placed on the support reference surface, the temperature-resistant distance sensor emits a distance measurement signal to the upper surface of the food to acquire the distance from the cavity cover reference position to the upper surface of the food; the damping adaptive controller 6 determines the food thickness based on the difference between the known distance from the sealed cavity cover to the support reference surface and the measured distance.

[0047] In another embodiment, the food thickness acquisition unit 51 includes multiple lateral ranging sensors disposed on the sidewall of the cavity. These sensors are spaced apart along the height of the cavity to identify occlusion or reflection of the food at different heights. The hindrance adaptive controller 6 obtains the food stacking height and local thickness distribution based on the detection results of the multiple lateral ranging sensors. For thick food items such as whole pieces of beef, chicken legs, pig's trotters, and radish chunks, the system can use the maximum detected thickness as a control parameter; for sliced ​​or mixed block food items, the system can use the average thickness corresponding to multiple detection points as a control parameter. In yet another embodiment, the food thickness acquisition unit 51 may further include a weighing sensor and a liquid level sensor. The weighing sensor obtains the food weight, and the liquid level sensor obtains the liquid level change after the addition of seasoning liquid. The hindrance adaptive controller 6 estimates the equivalent thickness of the food based on the food weight, liquid level change, and preset food type parameters. This method is suitable for situations where the food stacking state within the cavity is irregular, and single-point ranging is insufficient to accurately reflect the overall thickness. By acquiring the thickness of the food ingredients, the adaptive controller 6 can correct the target pressure, the hyperbolic asymptotic pressure ramp time, the proportion of high-frequency sweep, and the hyperbolic pressure-breathing fluctuation time. The greater the thickness of the food ingredients, the longer the mass transfer path required for the seasoning liquid to enter the core of the food ingredients is determined by the system. Therefore, the pressure-breathing fluctuation time near the target pressure is appropriately extended, and the proportion of permeation-type high-frequency ultrasound is increased.

[0048] The conductivity sensor 52 is used to acquire the conductivity of the seasoning liquid, including the initial conductivity and the real-time conductivity during the stewing process. In one embodiment, the conductivity sensor 52 is located in the lower liquid collection area of ​​the sealed stewing chamber 1, and the sensor probe extends into the seasoning liquid. The probe of the conductivity sensor 52 is provided with a heat-resistant protective sleeve and an anti-adhesion filter cover. The anti-adhesion filter cover is used to prevent food debris, spice particles, or condensates from directly adhering to the probe surface, reducing detection errors.

[0049] In another embodiment, a detection branch is provided on the lower side of the sealed stewing chamber 1. The detection branch includes a liquid inlet, a micro-sampling chamber, and a liquid return outlet. The conductivity sensor 52 is disposed in the micro-sampling chamber. During stewing, a small amount of seasoning liquid flows through the micro-sampling chamber under pressure difference or the action of a circulation pump, allowing the conductivity sensor 52 to perform detection under a relatively stable flow condition. This structure can prevent food from directly colliding with the probe and can also reduce the influence of uneven local soup concentration on the detection results.

[0050] After system startup, before heating and venting or at the initial stage of venting, the conductivity sensor 52 collects the initial conductivity of the seasoning liquid. This initial conductivity represents the initial concentration level of ionic or polar flavoring components such as salt, acidulants, and soluble umami substances in the seasoning liquid. During stewing, the conductivity sensor 52 collects real-time conductivity according to a preset sampling period. The hysteresis adaptive controller 6 obtains the real-time conductivity decrease rate based on the changes in real-time conductivity within adjacent sampling periods. Generally, when soluble flavoring components in the seasoning liquid migrate towards the surface and interior of the food, the conductivity of the seasoning liquid will show a decreasing trend; when the decrease rate gradually decreases, it indicates that the speed at which flavoring components continue to migrate into the interior of the food is decreasing. To reduce the influence of temperature on conductivity detection, the conductivity sensor 52 can work in conjunction with a temperature detection unit. The hysteresis adaptive controller 6 performs temperature compensation on the conductivity detection value based on the current temperature of the seasoning liquid, so that the conductivity changes collected at different stewing stages better reflect the migration state of flavoring components, rather than simply reflecting conductivity fluctuations caused by temperature changes.

[0051] The turbidity sensor 53 is used to acquire the turbidity of the seasoning liquid to determine the extent of food tissue damage, protein precipitation, starch release, or increased food debris. In one embodiment, the turbidity sensor 53 is disposed within the flow area of ​​the seasoning liquid, preferably in the detection branch at the lower part of the sealed stewing chamber 1, adjacent to the conductivity sensor 52. The turbidity sensor 53 includes a light-emitting unit and a light-receiving unit. The light-emitting unit emits detection light into the seasoning liquid flowing through the detection branch, and the light-receiving unit receives transmitted or scattered light and generates a turbidity signal based on changes in the received light intensity.

[0052] In another embodiment, the turbidity sensor 53 is disposed on the inner wall of the sealed stewing cavity 1, with its detection window facing the liquid area inside the cavity. A transparent heat-resistant protective sheet is disposed on the outer side of the detection window, and the outer surface of the protective sheet may be coated with a hydrophobic and oleophobic coating to reduce the adhesion of grease, protein coagulation, or seasoning particles. To avoid food directly obstructing the detection window, the turbidity sensor 53 is preferably arranged in a position that avoids obstruction of the liquid reflux area, the bottom confluence area, or the side wall of the cavity.

[0053] During the stewing process, the turbidity sensor 53 periodically collects the turbidity of the seasoning liquid. When the adaptive controller 6 determines that the turbidity rises rapidly in a short period of time, or that the change in turbidity exceeds the preset risk threshold, it indicates that there may be issues such as surface breakage of ingredients, meat fiber breakage, cracking of bean products, excessive starch precipitation, or increased emulsification of the broth. At this time, the tissue protection module can limit the output of cavitation-type low-frequency ultrasound, reduce the amplitude of hyperbolic pressure respiration fluctuations, or extend the period of hyperbolic pressure respiration fluctuations to make pressure changes smoother, thereby reducing the risk of further damage to the food tissue. The turbidity sensor 53 enables the system to not only pursue flavor absorption efficiency but also protect the integrity of the ingredients. For example, when the low-frequency cavitation ultrasound is too strong, the turbidity of the seasoning liquid may rise rapidly; the system accordingly reduces the output power of the cavitation-type low-frequency region or shortens its residence time to avoid causing turbidity in the broth and breakage of ingredients in order to enhance flavor absorption.

[0054] The ultrasonic echo transceiver unit 54 is used to acquire initial and real-time ultrasonic echoes, and reflects the acoustic state of the interface between the food and seasoning liquid, as well as the internal tissue interface of the food, based on echo changes. In one embodiment, the ultrasonic echo transceiver unit 54 includes a probe ultrasonic transmitter, an echo receiver, and an isolation drive circuit. The probe ultrasonic transmitter and echo receiver can be respectively disposed on opposite sidewalls of the sealed stewing cavity 1, or they can be integrated into a transceiver probe and disposed on the sidewall of the cavity or inside the cavity cover. Preferably, the detection direction of the ultrasonic echo transceiver unit 54 is towards the main area where the food is placed, so that the probe ultrasonic can sequentially pass through the seasoning liquid, the surface interface of the food, and the internal tissue area of ​​the food. The frequency of the probe ultrasonic can be selected to be a different detection frequency than that of the sweep frequency ultrasonic component 4, or short pulse detection can be performed during the interval when the sweep frequency ultrasonic component 4 stops outputting, so as to avoid interference of the sweep frequency ultrasonic output signal with the echo detection.

[0055] Before stewing begins, the ultrasonic echo transceiver unit 54 transmits probe ultrasound and receives initial ultrasonic echoes. These initial ultrasonic echoes represent the acoustic response of the food when it has not fully absorbed liquid and has not softened significantly. During stewing, the ultrasonic echo transceiver unit 54 transmits probe ultrasound at preset sampling times or during frequency sweep intervals to acquire real-time ultrasonic echoes. The hysteresis adaptive controller 6 compares the real-time ultrasonic echoes with the initial ultrasonic echoes to obtain the ultrasonic echo attenuation amount and the ultrasonic echo attenuation rate.

[0056] When food absorbs seasoning liquid, the liquid content in its internal pores increases, or its tissues gradually relax, the reflection, scattering, and attenuation characteristics of ultrasound waves at the food-seasoning liquid interface and the internal tissue interface change. Typically, as the food absorbs liquid and softens, the echo amplitude, echo arrival time, echo envelope shape, and attenuation level change accordingly. The hysteresis adaptive controller 6 can generate an ultrasonic echo attenuation rate based on the echo amplitude decrease rate, echo energy attenuation rate, or echo envelope change rate, to characterize the process of liquid absorption and tissue relaxation within the food. To ensure detection stability, the ultrasonic echo transceiver unit 54 can use multiple short-pulse sampling and averaging to reduce the impact of factors such as air bubbles in the cavity, slight movement of the food, and floating seasoning particles on the results of a single echo. For cases with a large food thickness, the system can also adjust the detection ultrasonic emission intensity, receiving gain, and echo sampling time window based on the thickness information provided by the food thickness acquisition unit 51, ensuring that the echo signal covers the surface interface and part of the internal tissue interface of the food.

[0057] The food detection component 5 works in conjunction with the adaptive resistance controller 6. The data collected by the food detection component 5 is not used in isolation, but is input together into the adaptive resistance controller 6. Specifically, the food thickness acquisition unit 51 provides the food thickness, which is used to correct the target pressure, the hyperbolic asymptotic pressure increase duration, and the high-frequency sweep ratio; the conductivity sensor 52 provides the conductivity of the seasoning liquid, which is used to calculate the real-time conductivity decrease rate; the ultrasonic echo transceiver unit 54 provides the initial ultrasonic echo and the real-time ultrasonic echo, which is used to calculate the ultrasonic echo attenuation rate; and the turbidity sensor 53 provides the turbidity of the seasoning liquid, which is used to determine the risk of food tissue damage.

[0058] The adaptive resistance controller 6 first records the initial conductivity and initial ultrasonic echo of the seasoning liquid before stewing begins, serving as a benchmark for subsequent changes. During stewing, the adaptive resistance controller 6 collects real-time conductivity and real-time ultrasonic echo according to a preset sampling period, and calculates the conductivity decrease rate and ultrasonic echo attenuation rate. When both the conductivity decrease rate and ultrasonic echo attenuation rate decrease simultaneously, it indicates that the difficulty for the seasoning liquid to continue migrating into the food increases, and the flavor absorption resistance coefficient increases. When the conductivity change slows down, the ultrasonic echo attenuation stabilizes, and the flavor absorption resistance coefficient is lower than a preset threshold, the system determines that the flavor absorption process is stabilizing, and can stop the frequency sweeping ultrasound and enter the pressure stabilization cooking process or determine that the pressure stabilization cooking process has ended. Through the structural design and data acquisition method of the above-mentioned food detection component 5, this embodiment can provide multi-dimensional detection basis for the generation of the flavor absorption resistance coefficient, avoiding the reliance solely on time, temperature, or pressure to judge the flavor absorption status of the food, thereby improving the adaptability of the gradient pressure stewing system to different thicknesses, different tissue densities, and different seasoning liquid formulas.

[0059] The adaptive controller for retardation includes a flavor retardation coefficient generation module, a hyperbola cooperative trajectory generation module, and an adaptive correction module.

[0060] In this embodiment, the hysteresis adaptive controller 6 is mounted on the control circuit board of the stewing system and can be composed of a microcontroller, an embedded processor, a memory, a signal acquisition circuit, an ultrasonic drive interface, a heating control interface, a proportional pressure relief valve control interface, and a safety protection circuit. The hysteresis adaptive controller 6 is connected to the food detection component, the heating and exhaust component, the controllable pressure regulating component, and the frequency sweeping ultrasonic component, respectively, and is used to generate pressure control parameters and frequency sweeping ultrasonic control parameters based on food thickness, seasoning liquid conductivity, seasoning liquid turbidity, ultrasonic echo, and intracavitary pressure data. The hysteresis adaptive controller 6 includes a flavor absorption hysteresis coefficient generation module 62, a hyperbola cooperative trajectory generation module 63, and an adaptive correction module 64. These modules can be implemented using control programs, logic circuits, or a combination of hardware and software. Among them, the flavor penetration resistance coefficient generation module 62 is used to determine the ease or difficulty of the seasoning liquid continuing to migrate into the food; the hyperbola collaborative trajectory generation module 63 is used to generate pressure change trajectory and frequency sweep ultrasound change trajectory based on the flavor penetration resistance coefficient; the adaptive correction module 64 is used to dynamically correct the subsequent pressure rise slope, pressure respiration fluctuation time and high frequency sweep ratio based on the changing trend of the flavor penetration resistance coefficient.

[0061] The implementation of the flavor absorption resistance coefficient generation module 62 involves connecting the module to a conductivity sensor, an ultrasonic echo transceiver unit, and a data storage unit. Before the system begins stewing, the flavor absorption resistance coefficient generation module 62 first records the initial conductivity and initial ultrasonic echo of the seasoning liquid, using these as subsequent judgment criteria.

[0062] During the stewing process, the conductivity sensor acquires the real-time conductivity of the seasoning liquid according to a preset sampling period, and the ultrasonic echo transceiver unit acquires real-time ultrasonic echoes during the intervals when the sweeping ultrasonic component stops outputting. The flavor absorption hindrance coefficient generation module 62 obtains the real-time conductivity decrease rate based on the change in the conductivity of the seasoning liquid within adjacent sampling periods; simultaneously, it obtains the ultrasonic echo attenuation rate based on the amplitude change, energy change, or envelope attenuation change between the real-time ultrasonic echo and the initial ultrasonic echo. Specifically, the real-time conductivity decrease rate is used to characterize the speed at which soluble flavoring components in the seasoning liquid migrate to the food. When the real-time conductivity decreases rapidly, it indicates that salt, umami substances, or other soluble components in the seasoning liquid are still continuously migrating to the surface and interior of the food; when the real-time conductivity decrease rate gradually decreases, it indicates that the migration speed of the flavoring components continues to decrease, and the continued absorption of the seasoning liquid by the food slows down. The ultrasonic echo attenuation rate is used to characterize the liquid absorption and tissue relaxation state inside the food. When food absorbs seasoning liquid, the liquid content in the pores increases, or the internal fibrous tissue gradually loosens, the amplitude, energy, and echo envelope shape of the ultrasonic echo will change. When the ultrasonic echo attenuation rate gradually decreases, it indicates that the change in liquid absorption inside the food is slowing down, and it becomes more difficult for the seasoning liquid to continue to migrate inward.

[0063] In this embodiment, the flavor penetration resistance coefficient generation module 62 normalizes the real-time conductivity decrease rate and the ultrasonic echo attenuation rate, respectively, to convert them to the same evaluation scale. After normalization, the flavor penetration resistance coefficient generation module 62 performs inverse weighted fusion on the characterization of the migration rate of seasoning components and the characterization of liquid absorption and tissue relaxation inside the food to generate the flavor penetration resistance coefficient. The so-called inverse weighted fusion means that the lower the real-time conductivity decrease rate and the lower the ultrasonic echo attenuation rate, the larger the generated flavor penetration resistance coefficient; when the real-time conductivity decrease rate and the ultrasonic echo attenuation rate are high, the generated flavor penetration resistance coefficient is small. For example, the normalized value corresponding to the real-time conductivity decrease rate can be used as the first migration factor, and the normalized value corresponding to the ultrasonic echo attenuation rate can be used as the second migration factor. When both the first and second migration factors are small, the flavor penetration resistance coefficient generation module 62 determines that the resistance to the seasoning liquid entering the food is large, and outputs a high flavor penetration resistance coefficient. When both the first and second migration factors are large, it determines that the seasoning liquid is still in a relatively active migration state, and outputs a low flavor penetration resistance coefficient. To avoid control fluctuations caused by single sampling errors, the flavor penetration resistance coefficient generation module 62 can perform a moving average processing on the real-time conductivity decrease rate, ultrasonic echo attenuation rate, and flavor penetration resistance coefficient over multiple consecutive sampling periods. When a sampling point becomes abnormal due to food movement, bubble interference, or instantaneous sensor fluctuations, the flavor penetration resistance coefficient generation module 62 can remove the abnormal value or reduce its weight in the fusion process. In this way, the flavor penetration resistance coefficient generation module 62 can combine the "change in seasoning liquid concentration" and the "change in the acoustic state inside the food," no longer relying solely on stewing time or pressure value to judge the flavor penetration process, thus providing a dynamic basis for subsequent hyperbolic pressure control and frequency sweep ultrasonic control.

[0064] The hyperbolic collaborative trajectory generation module 63 is connected to the flavor absorption resistance coefficient generation module 62, the adaptive correction module 64, the controllable pressure adjustment component, and the frequency sweeping ultrasound component, respectively, and is used to generate pressure control trajectories and frequency sweeping ultrasound control trajectories based on the flavor absorption resistance coefficient. In this embodiment, the pressure control trajectory generated by the hyperbolic collaborative trajectory generation module 63 includes an asymptotic pressure increase segment and a respiratory fluctuation segment. In the asymptotic pressure increase segment, the hyperbolic collaborative trajectory generation module 63 controls the heating exhaust component and the controllable pressure adjustment component to make the pressure inside the sealed stewing chamber rise to the target pressure in a hyperbolic asymptotic manner with a faster initial rise followed by a slower rise. That is, in the initial stage of pressure increase, the system adopts a larger pressure increase slope to make the pressure inside the chamber rise rapidly, so as to quickly establish the pressure driving force required for the migration of the seasoning liquid into the interior of the ingredients; as the pressure gradually approaches the target pressure, the pressure increase slope gradually decreases, so that the pressure approaches the target pressure in a way that does not have obvious overshoot, avoiding rapid pressure changes that could cause the surface tissue of the ingredients to be compacted or ruptured, or the soup to churn violently.

[0065] During the respiratory fluctuation phase, the hyperbolic collaborative trajectory generation module 63 controls the pressurization unit and the proportional pressure relief valve to periodically increase and decrease the intracavitary pressure around the target pressure, forming a hyperbolic pressure respiratory fluctuation. Each respiratory cycle includes a small pressurization process and a small depressurization process, with both the pressurization and depressurization slopes changing rapidly at the beginning and slowly at the end. Thus, when the pressure rises, the seasoning liquid is gently pressed into the pores of the food surface; when the pressure drops, a slight pressure difference is formed between the inside of the food and the external seasoning liquid, which facilitates the inhalation of the seasoning liquid along the pores, interfiber spaces, and interstitial spaces of the food; during the next pressure rebound, the seasoning liquid that has entered the food pores is retained inside, reducing reverse outflow. Simultaneously, the hyperbolic collaborative trajectory generation module 63 also generates a swept-frequency ultrasound control trajectory. This swept-frequency ultrasound control trajectory is used to control the swept-frequency ultrasound component to migrate from the cavitation-type low-frequency region through the mass transfer transition frequency region to the penetration-type high-frequency region. Specifically, in the initial stage of the frequency sweep, the ultrasonic frequency is located in the cavitation-type low-frequency region of 20–45 kHz, with a short residence time and a large sweep rate of change, which is used to form short-term cavitation disturbances, causing the bubbles attached to the surface of the food to detach and form reversible micro-perturbation channels; in the middle stage of the frequency sweep, the ultrasonic frequency passes through the mid-frequency mass transfer region of 45–120 kHz, which is used to enhance the exchange of seasoning liquid near the surface of the food and weaken the low-concentration boundary layer on the surface of the food; in the later stage of the frequency sweep, the ultrasonic frequency enters the penetrating high-frequency region of 120–500 kHz, with an increased residence time and a decreased sweep rate of change, which is used to promote the continued diffusion of seasoning liquid along the micropores and fiber gaps inside the food under a gentler sound field.

[0066] In one specific embodiment, the hyperbolic cooperative trajectory generation module 63 maintains a correspondence between the pressure control trajectory and the swept-frequency ultrasonic control trajectory: in the early stage of the asymptotic pressure ramping phase, the swept-frequency ultrasonic enters the cavitation-type low-frequency region in a shorter time; in the later stage of the asymptotic pressure ramping phase to near the target pressure, the swept-frequency ultrasonic gradually enters the mid-frequency mass transfer region; during the hyperbolic pressure respiration fluctuation, the swept-frequency ultrasonic increases the residence time in the permeation-type high-frequency region, so that the pressure-induced liquid absorption effect and the high-frequency permeation effect act simultaneously on the interior of the food. In another specific embodiment, the hyperbolic cooperative trajectory generation module 63 can modify the target pressure, asymptotic pressure ramping duration, and swept-frequency trajectory according to the thickness of the food. For thicker beef chunks, pig trotters, chicken legs, whole bean products, or root vegetables, the system increases the sweep frequency ratio in the permeation-type high-frequency region and prolongs the hyperbolic pressure respiration fluctuation time near the target pressure; for thinner or more fragile foods, the system reduces the output power and residence time in the cavitation-type low-frequency region and reduces the amplitude of the pressure respiration fluctuation. With the above settings, the hyperbola collaborative trajectory generation module 63 makes the pressure change no longer a simple linear increase or fixed pressure maintenance, and also makes the ultrasonic output no longer a fixed frequency action, but forms a pressure-ultrasonic collaborative trajectory that matches the state of the ingredients being seasoned.

[0067] The adaptive correction module 64 is connected to the flavor penetration resistance coefficient generation module 62, the hyperbola cooperative trajectory generation module 63, the tissue protection module, and the execution control module, respectively, and is used to adjust the pressure parameters and ultrasonic parameters of subsequent control cycles according to the changing trend of the flavor penetration resistance coefficient. In this embodiment, the adaptive correction module 64 judges the change of the flavor penetration resistance coefficient on a sampling cycle basis. When the flavor penetration resistance coefficient increases relative to the previous sampling cycle, it indicates that the difficulty of the seasoning liquid continuing to migrate into the food has increased. At this point, the adaptive correction module 64 sends a correction command to the hyperbolic collaborative trajectory generation module 63, causing the subsequent control cycle to execute at least one of the following control actions: First, reduce the pressure ramp rate in the subsequent control cycle to make the pressure change smoother, preventing further compaction of the food surface and thus preserving pore channels for the continued migration of the seasoning liquid into the interior; Second, extend the hyperbolic pressure breathing fluctuation time, allowing the food to experience more small pressure rises and falls near the target pressure, enhancing the pore absorption and retention of liquid; Third, increase the proportion of high-frequency sweep frequency, allowing the sweep frequency ultrasound to remain in the penetrating high-frequency region for a longer time, reducing the damage of low-frequency cavitation to the food surface, while promoting the diffusion of seasoning liquid in the internal micropores and fiber gaps; Fourth, reduce the output power of the cavitation-type low-frequency region or shorten the low-frequency residence time to avoid blindly enhancing low-frequency cavitation when the flavor absorption resistance increases, which could cause the food surface to break down; Fifth, increase the holding time near the target pressure, further stabilizing the internal temperature and tissue relaxation of the food, providing more sufficient conditions for the diffusion of the seasoning liquid. When the flavor penetration resistance coefficient is lower than a preset threshold within a preset number of consecutive sampling periods, the adaptive correction module 64 determines that the resistance to the continued migration of the seasoning liquid into the food is low, or that the flavor penetration process has stabilized. At this time, the adaptive correction module 64 controls the frequency sweeping ultrasonic component to stop the frequency sweeping ultrasonic output, or retains only low-power penetrating high-frequency ultrasonic, and controls the system to switch to a stable pressure cooking state. In the stable pressure cooking state, the system mainly maintains the cooking of the food through temperature and pressure, and no longer performs strong cavitation or high-intensity frequency sweeping processing, thereby reducing energy consumption and lowering the risk of tissue damage.

[0068] In a further embodiment, the adaptive correction module 64 also receives abnormal signals from the turbidity sensor and the ultrasonic echo transceiver unit. When the turbidity of the seasoning liquid rises abnormally, the ultrasonic echo changes abruptly, or the conductivity fluctuates abnormally, the adaptive correction module 64 prioritizes the execution of tissue protection strategies. For example, it limits the cavitation-type low-frequency output, reduces the amplitude of hyperbolic pressure respiration fluctuations, prolongs a single respiratory cycle, or enters a low-power stable-pressure cooking state earlier. This prevents the system from continuing to amplify ultrasonic or pressure disturbances when the ingredients are already showing signs of breaking down. During a stewing process, the retardation adaptive controller 6 can operate according to the following process: First, before heating and venting, the system acquires the thickness of the ingredients, the initial conductivity of the seasoning liquid, and the initial ultrasonic echo, and stores them as initial parameters. Second, the heating and venting assembly operates, causing the sealed stewing chamber to expel air and establish an initial thermal environment. After venting is completed, the retardation adaptive controller 6 activates the flavor absorption retardation coefficient generation module 62, and begins periodically acquiring real-time conductivity and real-time ultrasonic echoes. Then, the flavor penetration resistance coefficient generation module 62 generates a flavor penetration resistance coefficient based on the real-time conductivity decrease rate and ultrasonic echo attenuation rate, and inputs the flavor penetration resistance coefficient into the hyperbolic collaborative trajectory generation module 63. Next, the hyperbolic collaborative trajectory generation module 63 generates an asymptotic pressure increase trajectory, a hyperbolic pressure respiration fluctuation trajectory, and a hyperbolic sweep frequency ultrasonic trajectory based on the current flavor penetration resistance coefficient, so that the controllable pressure regulating component and the sweep frequency ultrasonic component work synchronously. During operation, the adaptive correction module 64 continuously compares the flavor penetration resistance coefficient of the current sampling period with that of the previous sampling period. When the flavor penetration resistance coefficient increases, it indicates that it is becoming more difficult for the seasoning liquid to continue to migrate inward. The adaptive correction module 64 reduces the subsequent pressure increase slope, prolongs the pressure respiration fluctuation time, and increases the proportion of high-frequency sweep frequency. When the flavor penetration resistance coefficient is continuously lower than the preset threshold, the adaptive correction module 64 stops the sweep frequency ultrasonic and switches the system to a stable pressure maturation state. Finally, in the pressure stabilization and maturation state, the resistance adaptive controller 6 determines whether the pressure stabilization and maturation process has ended based on the slowing down of the real-time conductivity change, the stabilization of the ultrasonic echo attenuation, and the flavor absorption resistance coefficient being lower than the preset threshold. It then controls the heating exhaust component, the controllable pressure regulating component, and the frequency sweeping ultrasonic component to stop or enter the heat preservation state.

[0069] The technical advantages of this embodiment are achieved by incorporating a flavor penetration resistance coefficient generation module 62, which integrates changes in the conductivity of the seasoning liquid and changes in ultrasonic echoes into a control parameter that reflects the difficulty of flavor penetration, thus avoiding insufficient or excessive flavor penetration caused by fixed-time stewing. By incorporating a hyperbolic collaborative trajectory generation module 63, this embodiment enables the intracavitary pressure to approach the target pressure in a rapid-then-slow manner, forming a gentle pressure breathing fluctuation near the target pressure. Simultaneously, the ultrasonic output gradually shifts from cavitation-type low frequency to penetration-type high frequency, thereby achieving continuous coordination of surface disturbance, enhanced mass transfer, and internal penetration. By incorporating an adaptive correction module 64, this embodiment dynamically adjusts the subsequent control cycle based on the changing trend of the flavor penetration resistance coefficient. This enhances high-frequency penetration and pressure breathing when flavor penetration is hindered, and promptly stops the sweeping ultrasound when flavor penetration stabilizes, reducing the risk of tissue damage and improving the consistency of stewing results.

[0070] The flavor penetration resistance coefficient generation module is used to generate a flavor penetration resistance coefficient based on the real-time conductivity decrease rate and the ultrasonic echo attenuation rate, and the flavor penetration resistance coefficient increases as the real-time conductivity decrease rate and the ultrasonic echo attenuation rate decrease.

[0071] In some embodiments, the flavor penetration resistance coefficient generation module operates as follows: In this embodiment, the flavor penetration resistance coefficient generation module is disposed within the resistance adaptive controller and is connected to the conductivity sensor, the ultrasonic echo transceiver unit, the data storage unit, and the hyperbolic cooperative trajectory generation module, respectively. The flavor penetration resistance coefficient generation module is used to generate a flavor penetration resistance coefficient that characterizes the difficulty of the seasoning liquid continuing to migrate into the food based on the changes in the conductivity of the seasoning liquid and the changes in the ultrasonic echo of the food. After the system is started, the user adds the food to be stewed and the seasoning liquid to the sealed stewing chamber. Before heating and venting or at the beginning of heating and venting, the conductivity sensor collects the initial conductivity of the seasoning liquid, and the ultrasonic echo transceiver unit emits probe ultrasound to the area where the food is located and receives the initial ultrasonic echo. The initial conductivity is used to represent the initial concentration state of soluble seasoning components in the seasoning liquid, and the initial ultrasonic echo is used to represent the acoustic response state of the food before it has fully absorbed the liquid and softened significantly. The flavor penetration resistance coefficient generation module stores the above-mentioned initial conductivity and initial ultrasonic echo as reference data.

[0072] During the stewing process, the conductivity sensor collects real-time conductivity data according to a preset sampling period. This sampling period can be set based on the type of food and the stewing mode, for example, collecting data every 5, 10, or 30 seconds. To avoid interference from changes in the temperature of the seasoning liquid on conductivity detection, the flavor absorption resistance coefficient generation module can use temperature detection data to compensate for the real-time conductivity, making the compensated conductivity changes more accurately reflect the migration of salt, umami substances, and other soluble seasoning components into the food.

[0073] The flavor penetration resistance coefficient generation module obtains the real-time conductivity decrease rate based on the real-time conductivity changes within adjacent sampling periods. Specifically, when salt and soluble flavoring components in the seasoning liquid continuously migrate towards the surface and interior of the food, the conductivity of the seasoning liquid usually shows a decreasing trend. If the conductivity decreases significantly per unit time, it indicates that the flavoring components are still in a relatively active migration state. If the conductivity decreases gradually less per unit time, it indicates that the rate at which migratable components in the seasoning liquid continue to enter the interior of the food is decreasing, and the flavor penetration process begins to be limited by the reduction in the pore size, fibrous structure, or internal and external concentration difference of the food. Simultaneously, the ultrasonic echo transceiver unit emits probe ultrasound during the intervals when the sweep frequency ultrasonic component stops outputting, and receives real-time ultrasonic echoes from the interface between the food and the seasoning liquid, as well as the interface between the internal tissues of the food. To avoid interference from the sweep frequency ultrasonic output on the detection signal, the probe ultrasound is preferably emitted as a short pulse within the intermittent window of the sweep frequency ultrasonic, or a detection frequency different from the sweep frequency ultrasonic is used. The flavor absorption resistance coefficient generation module compares the real-time ultrasonic echo with the initial ultrasonic echo to obtain the ultrasonic echo attenuation, and further obtains the ultrasonic echo attenuation rate based on the change of ultrasonic echo attenuation in adjacent sampling periods.

[0074] The ultrasonic echo attenuation rate is used to characterize the liquid absorption and tissue relaxation processes within the food. As the pores of the food gradually absorb seasoning liquid, the liquid content in the interfibrous spaces increases, or the tissue structure gradually relaxes, the reflection, scattering, and attenuation characteristics of ultrasound waves propagating within the food change, manifesting as a decrease in echo amplitude, attenuation of echo energy, or a change in the echo envelope shape. A high ultrasonic echo attenuation rate indicates that liquid absorption and tissue relaxation within the food are still progressing significantly; a gradually decreasing ultrasonic echo attenuation rate indicates that the changes in the acoustic state within the food are slowing down, and the effect of the seasoning liquid migrating further inward is weakening.

[0075] To ensure that the real-time conductivity decrease rate and ultrasonic echo attenuation rate can be evaluated on the same scale, the flavor absorption retardation coefficient generation module normalizes both. Specifically, the current real-time conductivity decrease rate is compared with the maximum conductivity decrease rate recorded during the early stages of stewing to obtain a measure of the migration speed of seasoning components; the current ultrasonic echo attenuation rate is compared with the maximum ultrasonic echo attenuation rate recorded during the early stages of stewing to obtain a measure of liquid absorption and tissue relaxation within the food. Both normalized measures represent the activity level of the current flavor absorption process; higher values ​​indicate more complete migration of seasoning liquid and liquid absorption within the food, while lower values ​​indicate a slower flavor absorption process. Subsequently, the flavor absorption retardation coefficient generation module performs inverse weighted fusion of the normalized measures of seasoning component migration speed and liquid absorption and tissue relaxation within the food to generate the flavor absorption retardation coefficient. The so-called reverse weighted fusion refers to the fact that the smaller the value of the migration speed of seasoning components and the smaller the value of liquid absorption and tissue relaxation inside the food, the larger the flavor absorption resistance coefficient; conversely, the larger the value of the migration speed of seasoning components and the larger the value of liquid absorption and tissue relaxation inside the food, the smaller the flavor absorption resistance coefficient. Therefore, the flavor absorption resistance coefficient can reflect the difficulty of the seasoning liquid continuing to migrate into the food.

[0076] In one specific implementation, the normalized value corresponding to the conductivity decrease rate can be used as the first activity factor, and the normalized value corresponding to the ultrasonic echo attenuation rate can be used as the second activity factor. When both the first and second activity factors are high, it indicates that the seasoning liquid is still continuously entering the food, and the flavor absorption resistance coefficient is set to a low level. When the first activity factor decreases while the second activity factor remains high, it indicates that the migration rate of soluble components in the seasoning liquid is decreasing, but there is still liquid absorption or tissue relaxation changes inside the food, and the flavor absorption resistance coefficient is at a moderate level. When both the first and second activity factors decrease, it indicates that the change in seasoning liquid concentration is slowing down and the change in the acoustic state inside the food is stabilizing, making it more difficult for the system to judge that the seasoning liquid continues to migrate into the food, and the flavor absorption resistance coefficient increases accordingly. To improve the stability of the judgment, the flavor absorption resistance coefficient generation module can also be equipped with a moving average processing unit and an outlier removal unit. The moving average processing unit is used to smooth the conductivity decrease rate, ultrasonic echo attenuation rate, and flavor absorption resistance coefficient within multiple consecutive sampling periods to avoid frequent fluctuations in control parameters caused by single sampling noise. The outlier removal unit is used to identify abnormal data caused by bubble adhesion, short-term contamination of the conductivity sensor, movement of ingredients, or violent stirring of soup. When a certain sampling value deviates significantly from the previous and subsequent sampling values, the flavor absorption resistance coefficient generation module can reduce the weight of that sampling value or replace it with a smooth value from an adjacent sampling period.

[0077] In a further embodiment, the flavor absorption resistance coefficient generation module can also perform protective correction on the flavor absorption resistance coefficient based on changes in the turbidity of the seasoning liquid. When the turbidity sensor detects a rapid increase in the turbidity of the seasoning liquid, it indicates that there may be surface breakage of the ingredients, protein precipitation, starch release, or a large number of suspended seasoning particles. At this time, even if the rate of decrease in conductivity or the rate of attenuation of ultrasonic echo still indicates that the flavor absorption process is active, the flavor absorption resistance coefficient generation module can also output a tissue protection prompt to the adaptive correction module to avoid the system misjudging that it is necessary to continue to enhance low-frequency cavitation or increase pressure fluctuations.

[0078] After the flavor penetration resistance coefficient is generated, the flavor penetration resistance coefficient generation module outputs the coefficient to the hyperbolic collaborative trajectory generation module and the adaptive correction module. If the flavor penetration resistance coefficient increases compared to the previous sampling period, it indicates that the difficulty of the seasoning liquid continuing to migrate into the food has increased. The adaptive correction module reduces the pressure ramp slope in subsequent control periods, prolongs the hyperbolic pressure respiration fluctuation time, and increases the proportion of sweep frequency ultrasound in the permeable high-frequency region. If the flavor penetration resistance coefficient is lower than the preset threshold within a preset number of consecutive sampling periods, it indicates that the flavor penetration process has become stable or the degree of resistance is low. The system stops sweep frequency ultrasound or only retains low-power permeable high-frequency ultrasound and enters the stable pressure cooking state.

[0079] Taking beef stew as an example, in the initial stage of stewing, the conductivity of the seasoning liquid decreases at a relatively high rate, and the ultrasonic echo attenuation rate is also relatively high. This indicates that salt and umami substances continue to migrate to the surface and interior of the beef, and the internal tissues of the beef gradually absorb the liquid and relax. At this time, the flavor absorption resistance coefficient is low. As stewing progresses, if the conductivity decreases significantly and the ultrasonic echo attenuation rate also decreases, it indicates that the beef is finding it more difficult to continue absorbing the seasoning liquid, and the flavor absorption resistance coefficient increases. Based on this, the system extends the hyperbolic pressure breathing fluctuation time near the target pressure and increases the residence ratio of penetrating high-frequency ultrasound, allowing the seasoning liquid to continue migrating into the beef under the combined effect of pressure breathing and high-frequency sound field. Through the above implementation method, the flavor absorption resistance coefficient generation module can integrate the changes in seasoning liquid concentration and the changes in the acoustic state of the food into a flavor absorption difficulty parameter that can be used for closed-loop control. This solves the problem that traditional stewing equipment judges the flavor absorption process based solely on time, temperature, or a fixed pressure program, thereby improving the uniformity of flavor absorption and the stewing stability of ingredients with different thicknesses and tissue structures.

[0080] The hyperbolic collaborative trajectory generation module is used to control the controllable pressure regulating component and the frequency sweeping ultrasound component according to the ingestion blockage coefficient, so that the intracavitary pressure rises to the target pressure in a hyperbolic asymptotic manner with a fast initial pressure followed by a slow pressure later, and forms a hyperbolic pressure respiratory fluctuation around the target pressure. At the same time, the frequency sweeping ultrasound component migrates from cavitation type low frequency to permeation type high frequency in a continuous frequency sweep or multi-transducer overlapping switching mode. The hyperbolic pressure respiratory fluctuation is a periodic pressure rise and fall around the target pressure, and both the pressure rise slope and the pressure fall slope change with a fast initial pressure followed by a slow pressure later.

[0081] In this embodiment, the hyperbolic cooperative trajectory generation module is housed within the hysteresis adaptive controller and is connected to the flavor absorption hysteresis coefficient generation module, the adaptive correction module, the controllable pressure adjustment component, and the frequency sweeping ultrasound component, respectively. The hyperbolic cooperative trajectory generation module receives the flavor absorption hysteresis coefficient and generates a pressure control trajectory and a frequency sweeping ultrasound control trajectory based on this coefficient, ensuring that the pressure changes within the sealed stewing chamber and the frequency sweeping ultrasound output changes maintain a coordinated relationship.

[0082] The controllable pressure regulating component includes a pressure boosting unit, a proportional pressure relief valve, and a pressure buffer chamber. The frequency sweeping ultrasonic component includes a broadband transducer capable of covering 20–500 kHz, or includes a low-frequency cavitation transducer with an operating frequency of 20–45 kHz, a medium-frequency mass transfer transducer with an operating frequency of 45–120 kHz, and a high-frequency permeation transducer with an operating frequency of 120–500 kHz. The hyperbolic collaborative trajectory generation module achieves synchronous control of the pressure trajectory and the ultrasonic trajectory by outputting heating power control signals, pressure boosting control signals, proportional pressure relief valve opening signals, ultrasonic frequency control signals, ultrasonic power control signals, and ultrasonic duty cycle control signals.

[0083] In some embodiments, the generation process of the hyperbolic asymptotic pressure rise trajectory is as follows: After heating and venting are completed, the hyperbolic cooperative trajectory generation module first enters the asymptotic pressure rise control state. The asymptotic pressure rise control state means that the pressure inside the sealed stewing chamber does not rise linearly with a fixed slope, nor does it rise rapidly to the target pressure in a sudden manner. Instead, it approaches the target pressure in a hyperbolic asymptotic manner, with a faster initial pressure rise followed by a gradual slowdown in the later stages. Specifically, the hyperbolic cooperative trajectory generation module determines the target pressure and pressure rise duration based on the food thickness, initial conductivity, initial ultrasonic echo, and current flavor absorption resistance coefficient. For foods with greater thickness, denser tissue, or higher flavor absorption resistance coefficient, the control time near the target pressure is appropriately extended; for foods with less thickness or that are fragile, both the pressure rise slope and the target pressure are appropriately reduced. In the initial stage of pressure rise, the hyperbolic cooperative trajectory generation module controls the pressurization unit and heating and venting components to operate at higher output, causing the chamber pressure to rise rapidly. The purpose of this stage is to quickly establish the pressure driving force required for the migration of the seasoning liquid to the surface and pore areas of the food, enabling the seasoning liquid to quickly adhere to and press against the food surface. As the pressure inside the chamber gradually approaches the target pressure, the hyperbolic collaborative trajectory generation module gradually reduces the output of the pressurization unit or the heating power, thus gradually decreasing the pressurization rate. This stage aims to prevent the pressure from exceeding the target pressure, thus preventing the sudden compaction and rupture of the food's surface tissue or the violent agitation of the seasoning liquid due to rapid pressurization. Through this hyperbolic asymptotic pressurization process, which is fast at the beginning and slow at the end, the system can balance the initial mass transfer driving force with the subsequent tissue protection.

[0084] In one implementation, the hyperbolic cooperative trajectory generation module can divide the pressurization process into a rapid establishment phase, a gradual approach phase, and a target approach phase. In the rapid establishment phase, the intracavitary pressure rises at a relatively high rate; in the gradual approach phase, the pressurization rate gradually decreases over time; and in the target approach phase, the pressure approaches the target pressure with a smaller change and avoids pressure overshoot. These three stages are not fixed steps but are continuously connected by a hyperbolic trajectory, making the pressure changes smoother.

[0085] In some embodiments, the formation process of hyperbolic pressure breathing fluctuations is as follows: when the intracavitary pressure approaches or reaches the target pressure, the hyperbolic cooperative trajectory generation module enters the hyperbolic pressure breathing fluctuation control state. The hyperbolic pressure breathing fluctuation refers to the periodic increase and decrease of intracavitary pressure around the target pressure, with the increase and decrease processes within each cycle exhibiting a rapid initial and slow subsequent change. Specifically, in one pressure breathing cycle, the hyperbolic cooperative trajectory generation module first controls the pressurization unit or heated exhaust assembly to slightly increase the intracavitary pressure, causing the intracavitary pressure to rise from below or near the target pressure to a preset range above the target pressure. During this pressurization process, the initial pressurization rate is high, followed by a gradual decrease in the pressurization rate, allowing the seasoning liquid to be gently pressed into the pores and fiber gaps on the surface of the food.

[0086] Subsequently, the hyperbolic collaborative trajectory generation module controls the proportional pressure relief valve to release pressure in small increments according to a gradually decreasing pressure relief opening, causing the pressure inside the cavity to slowly decrease from above the target pressure to below the target pressure or within a preset range near the target pressure. During this pressure reduction process, the initial pressure reduction rate is high, followed by a gradual decrease. Through this pressure reduction process, a gentle pressure difference is formed between the inside of the food and the external seasoning liquid, which facilitates the absorption of the seasoning liquid into the food along the micropores, fiber gaps, and tissue spaces. In the next pressurization cycle, the seasoning liquid that has entered the pores or fiber gaps of the food is retained inside the food due to external pressure, reducing the reverse outflow that would occur after the pressure drop. Thus, multiple hyperbolic pressure breathing cycles can form a cycle similar to "pressure-absorption-locking," allowing the seasoning liquid to gradually migrate into the food without drastically damaging its structure.

[0087] In this embodiment, the amplitude of the hyperbolic pressure respiration fluctuation is preferably less than a certain proportion of the target pressure to avoid violent splashing of the soup or tumbling of the food. For example, the hyperbolic cooperative trajectory generation module can control the amplitude of the pressure respiration fluctuation within a small range near the target pressure and weaken the instantaneous pressure shock caused by the opening and closing of the proportional pressure relief valve through the pressure buffer chamber. For fragile food, the hyperbolic cooperative trajectory generation module reduces the amplitude of the pressure respiration fluctuation and prolongs the single respiration cycle; for thick or dense food, the pressure respiration fluctuation time is appropriately prolonged to enhance the pore pumping effect.

[0088] In some embodiments, the sweep ultrasound control, which moves from cavitation-type low frequency to penetration-type high frequency, generates a sweep ultrasound control trajectory simultaneously with the pressure trajectory operation. This sweep ultrasound control trajectory enables the sweep ultrasound component to migrate from cavitation-type low frequency to penetration-type high frequency through continuous frequency sweeping or multi-transducer overlapping switching. In an embodiment employing a broadband transducer, the hyperbolic cooperative trajectory generation module directly controls the output frequency of the broadband transducer, gradually sweeping it from the cavitation-type low frequency region of 20–45 kHz to the mass transfer transition frequency region of 45–120 kHz, and then further sweeping it to the penetration-type high frequency region of 120–500 kHz. In the initial stage of frequency sweeping, the frequency changes rapidly and the low-frequency residence time is short, which is used to generate short-term cavitation disturbances, causing the bubbles attached to the surface of the food to detach and form reversible micro-perturbation channels; in the middle stage of frequency sweeping, the frequency passes through the mass transfer transition region, which is used to enhance the exchange of seasoning liquid on the surface of the food; in the later stage of frequency sweeping, the frequency change gradually slows down and the high-frequency residence time increases, which is used to enhance the diffusion of seasoning liquid in the micropores and fiber gaps inside the food.

[0089] In another implementation using multiple transducers, the frequency-sweeping ultrasound component includes a low-frequency cavitation transducer, a mid-frequency mass transfer transducer, and a high-frequency penetrating transducer. The hyperbolic cooperative trajectory generation module controls the start-up and shutdown sequence, output power, and duty cycle of each transducer to create overlapping switching between transducers of different frequencies. For example, at the beginning of the frequency sweep, the low-frequency cavitation transducer starts with a shorter duty cycle, and the mid-frequency mass transfer transducer pre-starts with lower power; subsequently, the power of the low-frequency cavitation transducer is gradually reduced, while the power of the mid-frequency mass transfer transducer is increased; then, the output ratio of the high-frequency penetrating transducer is gradually increased, allowing the ultrasonic effect to smoothly transition from surface cavitation disturbance to internal penetration and diffusion. Through overlapping switching of multiple transducers, an equivalent frequency shift effect can be achieved without relying on a single broadband transducer. During the frequency sweep, the hyperbolic cooperative trajectory generation module can also adjust the dwell time in different frequency regions according to the infiltration resistance coefficient. When the flavor penetration resistance coefficient is low, it means that the seasoning liquid can still enter the food relatively smoothly, and the system can maintain a short high-frequency residence time. When the flavor penetration resistance coefficient increases, it means that the mass transfer inside the food is blocked. The hyperbolic collaborative trajectory generation module increases the residence ratio in the penetrating high-frequency region and reduces the output power in the cavitation low-frequency region to avoid excessive cavitation damaging the surface of the food.

[0090] In some embodiments, the synergistic relationship between the pressure trajectory and the swept-frequency ultrasound trajectory is as follows: the hyperbolic synergistic trajectory generation module does not independently control pressure and ultrasound, but rather coordinates and matches them temporally and mechanistically. In the early stage of hyperbolic asymptotic pressure increase, the intracavitary pressure is rapidly established, and the swept-frequency ultrasound is in the cavitation-type low-frequency region or the low-to-mid-frequency transition region. During this stage, short-term low-frequency cavitation reduces the adhesion of air bubbles to the food surface, opens the micro-perturbation channels on the food surface, and simultaneously uses the pressure increase to force the seasoning liquid towards the food surface. In the later stage of hyperbolic asymptotic pressure increase, the intracavitary pressure gradually approaches the target pressure, and the swept-frequency ultrasound gradually enters the mid-frequency mass transfer region. During this stage, mid-frequency acoustic microfluidics weakens the low-concentration boundary layer on the food surface, ensuring continuous contact between the food surface and the high-concentration seasoning liquid, preventing a rapid decrease in mass transfer rate after only localized surface flavoring. During the hyperbolic pressure respiration fluctuations near the target pressure, the swept-frequency ultrasound remains more in the permeation-type high-frequency region. This stage utilizes small, periodic pressure fluctuations to generate liquid absorption and retention effects, while simultaneously employing high-frequency ultrasound to create subtle sound pressure disturbances within the pores of the food, promoting the diffusion of the seasoning liquid inwards. Thus, the pressure breathing fluctuations and the high-frequency penetrating sound field work together to improve the problem of insufficient flavor absorption in the core of thicker food pieces.

[0091] When the inhalation resistance coefficient increases relative to the previous sampling period, the hyperbolic collaborative trajectory generation module, according to the instructions of the adaptive correction module, reduces the pressure ramp slope in subsequent control periods, prolongs the hyperbolic pressure-respiratory fluctuation time near the target pressure, and increases the residence time of the swept ultrasound in the permeable high-frequency region. When the inhalation resistance coefficient is lower than a preset threshold within a preset number of consecutive sampling periods, the hyperbolic collaborative trajectory generation module stops generating high-intensity swept trajectories, controls the swept ultrasound component to stop sweeping output or retain only low-power permeable high-frequency ultrasound, and switches the pressure control to a stable pressure stabilization mode.

[0092] In some embodiments, the hyperbolic trajectory parameters are corrected as follows: the hyperbolic collaborative trajectory generation module can correct the pressure trajectory and the swept-frequency ultrasonic trajectory based on the food thickness, the flavor penetration resistance coefficient, and the tissue protection signal. When the food thickness is large, the hyperbolic collaborative trajectory generation module extends the asymptotic pressurization time, reduces the later pressurization slope, and increases the number of hyperbolic pressure breathing fluctuation cycles, while increasing the sweep frequency ratio of the permeable high-frequency region. This provides a longer pressure drive and high-frequency diffusion time for the seasoning liquid to enter the food. When the food thickness is small or the system identifies the food as fragile, the hyperbolic collaborative trajectory generation module reduces the target pressure, reduces the pressure breathing fluctuation amplitude, shortens the low-frequency cavitation residence time, and limits the low-frequency output power. This can prevent food surface breakage, bean product cracking, fish meat loosening, or soup turbidity. When the tissue protection module detects an abnormal increase in the turbidity of the seasoning liquid, a sudden change in the ultrasonic echo, or an abnormal fluctuation in conductivity, the hyperbolic collaborative trajectory generation module immediately reduces the pressure breathing fluctuation amplitude, extends the breathing cycle, and reduces or stops the cavitation-type low-frequency output. If the abnormal state persists, it will switch to a stable pressure cooking state in advance.

[0093] In some embodiments, taking beef stew as an example, after the user adds the beef chunks and seasoning liquid to the sealed stewing chamber, the ingredient detection component acquires the thickness of the beef chunks, the initial conductivity of the seasoning liquid, and the initial ultrasonic echo. After heating and venting are completed, the flavor absorption resistance coefficient generation module begins to calculate the flavor absorption resistance coefficient. In the early stage of stewing, the hyperbolic cooperative trajectory generation module controls the pressure inside the chamber to increase rapidly at first and then slowly. At this time, the frequency sweeping ultrasound component briefly enters the 20-45kHz cavitation-type low-frequency region, causing the air bubbles attached to the surface of the beef to detach and form a micro-perturbation channel. Subsequently, as the pressure gradually approaches the target pressure, the frequency sweeping ultrasound migrates to the 45-120kHz mass transfer transition frequency region, allowing the seasoning liquid to maintain a good exchange state on the surface of the beef. When the pressure reaches near the target pressure, the hyperbolic cooperative trajectory generation module controls the proportional pressure relief valve and the pressurization unit to work alternately, causing the pressure inside the chamber to fluctuate slightly around the target pressure. At the same time, the frequency sweeping ultrasound gradually increases the residence time in the 120-500kHz penetrating high-frequency region, allowing the seasoning liquid to diffuse into the interfiber gaps inside the beef under the action of pressure suction and high-frequency sound field.

[0094] If the system detects an increase in the flavor absorption resistance coefficient, it indicates that further flavor absorption into the beef is hindered. The hyperbolic collaborative trajectory generation module extends the pressure respiration fluctuation time and further increases the proportion of high-frequency sweep. If the flavor absorption resistance coefficient is below the threshold within a preset number of consecutive sampling periods, the system stops the frequency sweep ultrasound and switches to stable pressure cooking. Through this process, beef chunks can achieve relatively uniform flavor absorption in a shorter time, while avoiding excessive breakage of the outer layer or excessive turbidity of the broth. Through the above implementation method, the hyperbolic collaborative trajectory generation module can unify intracavitary pressure changes and ultrasonic frequency migration into a continuous collaborative control process, transforming the mass transfer process of the seasoning liquid from simple natural diffusion into a composite process of "gradual pressure increase to establish driving force, pressure respiration to form liquid absorption and retention, and high-frequency sweep to enhance internal diffusion," thereby improving the uniformity of flavor absorption and the stability of stewing for thick-cut ingredients.

[0095] The adaptive correction module is used to reduce the pressure ramp slope, extend the hyperbolic pressure-respiratory fluctuation time and increase the proportion of high-frequency sweep frequency in subsequent control cycles when the ingestion resistance coefficient increases relative to the previous sampling cycle; and to stop the sweep frequency ultrasound and switch to the stable pressure maturation state when the ingestion resistance coefficient is lower than the preset threshold within a preset number of consecutive sampling cycles, and the real-time conductivity change slows down and the ultrasonic echo attenuation stabilizes.

[0096] In this embodiment, the adaptive correction module is housed within the hysteresis adaptive controller and is connected to the flavor penetration resistance coefficient generation module, the hyperbola cooperative trajectory generation module, the sweep frequency ultrasonic component, the controllable pressure regulating component, and the heating and exhaust component, respectively. The adaptive correction module dynamically corrects the pressure control parameters and sweep frequency ultrasonic control parameters in subsequent control cycles based on the changing trend of the flavor penetration resistance coefficient between adjacent sampling cycles. This enhances the internal penetration effect of the system when flavor penetration is hindered and promptly reduces disturbances and transitions to a stable pressure maturation state when flavor penetration stabilizes.

[0097] In some embodiments, the trend of the flavor absorption resistance coefficient is determined by the flavor absorption resistance coefficient generation module outputting the current flavor absorption resistance coefficient according to a preset sampling period during the stewing process. The sampling period can be set according to the type of ingredients, the thickness of the ingredients, and the stewing mode, for example, outputting once every 5 seconds, 10 seconds, 20 seconds, or 30 seconds. The adaptive correction module receives the flavor absorption resistance coefficient of the current sampling period and compares it with the flavor absorption resistance coefficient of the previous sampling period. When the current flavor absorption resistance coefficient is greater than the flavor absorption resistance coefficient of the previous sampling period, or when the current flavor absorption resistance coefficient shows an upward trend over multiple consecutive sampling periods, the adaptive correction module determines that the resistance to the continued migration of the seasoning liquid into the ingredients has increased. The reasons typically include: the surface of the ingredients has already absorbed a large amount of seasoning liquid, the concentration difference between the inside and outside has decreased, mass transfer through the pores inside the ingredients has slowed down, or the ingredients' tissues are gradually shrinking, leading to a decrease in their ability to continue absorbing liquid.

[0098] To avoid misjudgments caused by fluctuations in a single sampling period, the adaptive correction module can be configured with a trend confirmation mechanism. For example, it can be determined as a valid increase only when the current flavor absorption resistance coefficient increases relative to the previous sampling period, and the increase exceeds a preset minimum change; or it can be determined that the flavor absorption resistance coefficient has increased when the flavor absorption resistance coefficient shows an upward trend for two or more consecutive sampling periods. For abnormal values ​​caused by bubble interference, food turning, or instantaneous fluctuations in the sensor, the adaptive correction module can replace the current value with a moving average, or delay the parameter correction by one sampling period.

[0099] In some embodiments, when the flavor absorption resistance coefficient increases, the adaptive correction module first sends a pressure rise slope correction command to the hyperbolic collaborative trajectory generation module when it determines that the flavor absorption resistance coefficient has increased relative to the previous sampling period. This is used to reduce the pressure rise slope in subsequent control periods. Specifically, when the system is still in the hyperbolic asymptotic pressure rise phase, the adaptive correction module reduces the pressure increase per unit time of the pressurization unit or reduces the heating power of the heating exhaust assembly, so that the pressure inside the cavity continues to rise but the rate of rise decreases. This avoids the rapid increase in pressure causing the surface tissue of the food to be compacted, and prevents the formed micro-perturbation channels from contracting and closing, thereby preserving a pathway for the seasoning liquid to continue migrating into the interior of the food.

[0100] When the system has entered the hyperbolic pressure-breathing fluctuation phase, reducing the pressure ramp rate in subsequent control cycles manifests as reducing the small ramp rate within the next breathing cycle, making the pressure move more smoothly from the lower to the upper limit of the fluctuation. This reduces sudden compression of the food during pressure recovery, lowering the risk of seasoning liquid being squeezed out of the food's internal pores. For example, in a specific stewing cycle, if the system detects an increase in the flavor absorption resistance coefficient, the adaptive correction module will adjust the pressure ramp rate of the next control cycle to a preset proportion of the original ramp rate, such as 60% to 90%. This proportion can be adjusted according to the thickness of the food and the level of tissue protection. For dense foods such as beef shank and pig's trotters, the reduction can be smaller to maintain sufficient mass transfer driving force; for fragile foods such as fish pieces and tofu, the reduction can be larger to prioritize the protection of food integrity.

[0101] The hyperbolic pressure respiratory fluctuation time correction module further extends the hyperbolic pressure respiratory fluctuation time when the flavor absorption resistance coefficient increases. This hyperbolic pressure respiratory fluctuation time can manifest as an increase in the total duration of respiratory fluctuations, an increase in the number of respiratory fluctuation cycles, or a lengthening of individual respiratory cycles. In one embodiment, the adaptive correction module determines the number of additional respiratory fluctuation cycles based on the magnitude of the increase in the flavor absorption resistance coefficient. When the flavor absorption resistance coefficient increases slightly, only one or a small number of respiratory cycles are added; when the flavor absorption resistance coefficient increases significantly, multiple respiratory cycles are added, or the duration of each respiratory cycle is lengthened. By increasing the hyperbolic pressure respiratory fluctuation time, the food undergoes more gentle pressure increases and decreases near the target pressure, causing repeated liquid absorption and retention effects in the pores, fiber gaps, and tissue gaps of the food.

[0102] In another implementation, the adaptive correction module reduces the hyperbolic pressure-respiratory fluctuation frequency and extends the individual respiratory cycle. This allows for more thorough depressurization and liquid absorption, and prevents the seasoning liquid from being disturbed by the next pressure change before it can penetrate the food due to excessively rapid pressure fluctuations. For thick-cut meats and root vegetables, this method is beneficial for increasing the migration depth of the seasoning liquid in the core area. For example, when the flavor penetration resistance coefficient increases within a continuous sampling period, the adaptive correction module can extend the originally set pressure-respiratory fluctuation time from a first time length to a second time length, or increase the originally set number of respiratory cycles from a first number of cycles to a second number of cycles. If the tissue protection module simultaneously detects an increase in turbidity, the adaptive correction module prioritizes extending the individual cycle rather than increasing the fluctuation amplitude to prevent food breakage.

[0103] In some embodiments, the high-frequency sweep ratio is corrected when the flavor penetration resistance coefficient increases. When the flavor penetration resistance coefficient increases, the adaptive correction module also increases the high-frequency sweep ratio. The high-frequency sweep ratio refers to the proportion of the residence time or output energy of the sweep ultrasound in the penetrating high-frequency region during the entire sweep cycle. The penetrating high-frequency region is preferably 120–500 kHz. In one embodiment, the adaptive correction module extends the residence time of the sweep ultrasound in the 120–500 kHz region while shortening the residence time in the cavitation low-frequency region of 20–45 kHz. This reduces the continuous disturbance of the food surface by low-frequency cavitation, preventing food surface breakage or turbidity of the soup. At the same time, the subtle disturbance effect of the high-frequency sound field in micropores, fiber gaps, and tissue gaps promotes the continued diffusion of the seasoning liquid into the interior.

[0104] In another implementation, if the sweep ultrasound assembly employs a multi-transducer structure consisting of a low-frequency cavitation transducer, a mid-frequency mass transfer transducer, and a high-frequency penetrating transducer, the adaptive correction module increases the proportion of high-frequency sweep by reducing the duty cycle or output power of the low-frequency cavitation transducer and increasing the duty cycle or output power of the high-frequency penetrating transducer. If the sweep ultrasound assembly uses a broadband transducer, the adaptive correction module adjusts the sweep trajectory to allow the device to remain in the penetrating high-frequency region for a longer period in the later stages of the sweep, and further reduces the sweep rate of change. For example, when the ingestion resistance coefficient does not increase, a sweep cycle can be executed in a relatively balanced low-frequency, mid-frequency, and high-frequency migration pattern; when the ingestion resistance coefficient increases, the adaptive correction module adjusts the sweep trajectory to quickly pass through the cavitation low-frequency region and the mass transfer transition frequency region, and prolongs the stay in the penetrating high-frequency region, making high-frequency penetrating action the main ultrasound action mode in subsequent control cycles.

[0105] In some embodiments, the multi-parameter joint correction strategy is as follows: the adaptive correction module does not adjust only one parameter in isolation, but performs joint correction based on the degree of change in the flavor penetration resistance coefficient, the thickness of the ingredients, and the state of tissue protection. When the flavor penetration resistance coefficient increases slightly and the turbidity does not increase abnormally, the adaptive correction module can adopt a mild correction strategy, that is, slightly reduce the subsequent pressure ramp rate and appropriately increase the proportion of high-frequency sweep. When the flavor penetration resistance coefficient increases significantly and the thickness of the ingredients is large, the adaptive correction module adopts an enhanced penetration strategy, that is, reduce the subsequent pressure ramp rate, prolong the hyperbolic pressure respiration fluctuation time, and significantly increase the proportion of high-frequency sweep to enhance the flavor penetration into thick ingredients. When the flavor penetration resistance coefficient increases and the turbidity increases abnormally or the ultrasonic echo shows a sudden change, the adaptive correction module adopts a protective correction strategy, that is, limit or stop the cavitation-type low-frequency output, reduce the hyperbolic pressure respiration fluctuation amplitude, prolong the pressure respiration fluctuation period, and avoid increasing the flavor penetration speed by increasing the low-frequency cavitation intensity. This strategy can reduce surface breakage of ingredients, turbidity of the broth, or excessive damage to the tissue structure.

[0106] In some embodiments, the pressure-stabilized cooking process switches when the flavor penetration resistance coefficient is continuously below a threshold. When the flavor penetration resistance coefficient is below a preset threshold within a preset number of consecutive sampling periods, the adaptive correction module determines that the degree of resistance to the continued migration of the seasoning liquid into the food is already low, or the flavor penetration process has become stable. At this time, the benefits of continuing strong frequency sweeping ultrasound or hyperbolic pressure perturbation are reduced, and it may instead increase the risk of food tissue damage, increased energy consumption, or deterioration in taste. Therefore, the adaptive correction module controls the system to stop frequency sweeping ultrasound and switch to pressure-stabilized cooking.

[0107] The preset number of continuous sampling periods can be set according to the type of food and the stewing mode. For example, for thick pieces of meat, a longer number of continuous sampling periods can be set to avoid premature termination of the sweep ultrasound; for thin slices or fragile foods, a shorter number of continuous sampling periods can be set to allow the system to enter the stable pressure cooking state earlier. When entering the stable pressure cooking state, the adaptive correction module sends a stop sweep command to the sweep ultrasound component, or makes the sweep ultrasound component retain only low-power penetrating high-frequency ultrasound. At the same time, the adaptive correction module sends a pressure stabilization command to the controllable pressure regulating component to maintain the intracavitary pressure within the cooking target pressure range and to prevent significant hyperbolic pressure respiration fluctuations. The heating exhaust component adjusts its power according to the cooking target temperature to complete the cooking processes such as food softening, collagen conversion, starch gelatinization, or flavor fusion. During the stable pressure cooking process, the adaptive correction module can continue to receive real-time conductivity, ultrasonic echo, and turbidity data. When the real-time conductivity changes slowly, the ultrasonic echo attenuation stabilizes, and the flavor absorption resistance coefficient continues to be lower than the preset threshold, the system determines that the pressure stabilization and maturation process can end; if the turbidity increases abnormally, the heating power is reduced in advance or the system enters the heat preservation state.

[0108] In some embodiments, taking beef stew as an example, in the initial stage of stewing, the salt and umami substances in the seasoning liquid rapidly penetrate the surface and some internal tissues of the beef, resulting in a high rate of decrease in real-time conductivity, a high rate of ultrasonic echo attenuation, and a low flavor absorption resistance coefficient. At this time, the adaptive correction module does not make significant corrections, and the system operates according to the basic hyperbolic asymptotic pressure ramp and frequency sweep ultrasonic trajectory. As stewing progresses, the surface and outer fibers of the beef have absorbed a significant amount of seasoning liquid, and the rate of further flavor absorption decreases. If the flavor absorption resistance coefficient increases relative to the previous sampling period, the adaptive correction module reduces the subsequent pressure ramp slope to make the pressure change smoother; at the same time, it extends the hyperbolic pressure respiration fluctuation time near the target pressure, allowing the beef to generate more liquid absorption and retention during small pressure fluctuations; and it increases the proportion of 120–500 kHz penetrating high-frequency ultrasound, so that the high-frequency sound field continuously acts on the internal pores and fiber gaps of the beef.

[0109] After several sampling cycles, when the flavor penetration resistance coefficient continuously falls below the preset threshold, the real-time conductivity changes slowly, and the ultrasonic echo attenuation stabilizes, the adaptive correction module determines that the flavor penetration process has stabilized. It then controls the sweeping ultrasound to stop outputting and puts the system into a stable-pressure cooking state. Subsequently, the system primarily softens the beef by maintaining stable temperature and pressure, preventing further strong ultrasonic treatment from causing the outer layer of the meat to crumble. Through this implementation method, the adaptive correction module can dynamically adjust the pressure and ultrasonic control parameters according to the changing trend of the flavor penetration resistance coefficient. This allows the stewing system to enhance internal penetration when flavor penetration is hindered and to promptly reduce disturbances when flavor penetration stabilizes, thus balancing flavor uniformity, ingredient integrity, and stewing efficiency.

[0110] In some embodiments, the pressure control trajectory generated by the hyperbolic collaborative trajectory generation module includes an asymptotic pressure increase segment and a respiratory fluctuation segment. In the asymptotic pressure increase segment, the rate of pressure increase in the cavity gradually decreases with the increase of running time, so that the pressure gradually approaches the target pressure in a way that avoids pressure overshoot. In the respiratory fluctuation segment, the cavity pressure rises and falls periodically around the target pressure, and the pressure increase slope and pressure decrease slope in each cycle change from fast at the beginning to slow at the end.

[0111] In some embodiments, the frequency-sweeping ultrasound component includes a broadband transducer capable of covering 20–500 kHz, or includes a low-frequency cavitation transducer with an operating frequency of 20–45 kHz, a mid-frequency mass transfer transducer with an operating frequency of 45–120 kHz, and a high-frequency penetrating transducer with an operating frequency of 120–500 kHz. The hyperbolic frequency sweep method is as follows: in the initial stage of the frequency sweep, the residence time in the cavitation-type low-frequency region of 20–45 kHz is short and the frequency sweep change rate is large; in the middle stage of the frequency sweep, it passes through the mass transfer transition frequency region of 45–120 kHz; in the later stage of the frequency sweep, the residence time in the penetrating high-frequency region of 120–500 kHz increases and the frequency sweep change rate decreases, so that the frequency-sweeping ultrasound migrates from the cavitation-type low-frequency region through the mass transfer transition frequency region to the penetrating high-frequency region.

[0112] In some embodiments, the flavor penetration resistance coefficient generation module uses the rate of change between the initial conductivity and the real-time conductivity of the seasoning liquid as a measure of the migration speed of the seasoning components, and uses the attenuation rate between the initial ultrasonic echo and the real-time ultrasonic echo as a measure of liquid absorption and tissue relaxation inside the food. The flavor penetration resistance coefficient generation module normalizes the measure of the migration speed of the seasoning components and the measure of liquid absorption and tissue relaxation inside the food, and performs inverse weighted fusion on the normalized measure of the migration speed of the seasoning components and the measure of liquid absorption and tissue relaxation inside the food to generate the flavor penetration resistance coefficient.

[0113] In some embodiments, when the ingestion resistance coefficient increases relative to the previous sampling period, the adaptive correction module performs at least one of the following control actions: reducing the pressure increase per unit time of the controllable pressure regulating component, reducing the frequency of hyperbolic pressure respiratory fluctuations and prolonging a single respiratory cycle, increasing the residence time of the sweep ultrasound in the permeable high-frequency region, reducing the output power in the cavitation low-frequency region, and increasing the pressure holding time near the target pressure.

[0114] In some embodiments, the controllable pressure regulating component includes a pressure boosting unit, a proportional pressure relief valve, and a pressure buffer chamber; the pressure boosting unit is used to form an asymptotic pressure increase segment, the proportional pressure relief valve is used to form a hyperbolic pressure reduction process in the respiratory fluctuation segment according to the pressure relief opening signal output by the hysteresis adaptive controller, and the pressure buffer chamber is used to weaken pressure abrupt changes, so that the pressure rise and fall amplitude in the respiratory fluctuation segment is kept within a preset proportional range of the target pressure.

[0115] In some embodiments, the ultrasonic echo transceiver unit emits probe ultrasound during the interval when the sweep frequency ultrasonic component stops outputting, and receives echo signals from the interface between the food and the seasoning liquid and the interface between the internal tissues of the food, so as to avoid the sweep frequency ultrasonic output signal interfering with the calculation of the flavor absorption resistance coefficient.

[0116] In some embodiments, the adaptive controller further includes a food thickness correction module; the food thickness correction module is used to correct the target pressure, the hyperbolic asymptotic pressure rise time, and the high-frequency sweep ratio according to the food thickness; the greater the food thickness, the longer the hyperbolic pressure respiratory fluctuation time near the target pressure, and the higher the high-frequency sweep ratio.

[0117] In some embodiments, the hysteresis adaptive controller further includes a tissue protection module; the tissue protection module determines the risk of food tissue damage based on ultrasonic echo mutations, abnormal conductivity fluctuations, and / or abnormal increases in the turbidity of the seasoning liquid; when the risk of food tissue damage exceeds a preset risk threshold, it limits the cavitation-type low-frequency output, reduces the amplitude of hyperbolic pressure respiration fluctuations, and / or prolongs the hyperbolic pressure respiration fluctuation period.

[0118] In some embodiments, the pressure stabilization and maturation state is as follows: stop the frequency sweeping ultrasound or only retain the low-power penetrating high-frequency ultrasound, control the intracavitary pressure to maintain within the maturation target pressure range, and determine the end of the pressure stabilization and maturation process based on the slowing down of real-time conductivity changes, the stabilization of ultrasound echo attenuation, and the flavor penetration resistance coefficient being lower than a preset threshold.

[0119] In some embodiments, the system of this application may include the following hardware: A sealed stewing chamber assembly includes a food-grade stainless steel inner pot, a pressure-resistant outer shell, a sealed chamber cover, a silicone sealing ring, a mechanical safety pressure relief valve, an exhaust port, a sensor mounting interface, and an ultrasonic transducer mounting base. A heating and exhaust assembly includes a bottom heating plate, a sidewall auxiliary heating film or annular heating belt, a temperature sensor, an exhaust channel, and an electrically controlled exhaust valve. A controllable pressure regulating assembly includes a pressure boosting unit, a proportional pressure relief valve, a pressure buffer chamber, a mechanical safety pressure relief valve, and a pressure sensor. A swept-frequency ultrasonic assembly includes a low-frequency cavitation transducer, a medium-frequency mass transfer transducer, a high-frequency permeation transducer, or a broadband ultrasonic transducer group, and is equipped with a swept-frequency ultrasonic drive power supply. A food detection assembly includes a food thickness acquisition unit, a conductivity sensor, a turbidity sensor, an ultrasonic echo transceiver unit, a liquid level detection unit, and a temperature compensation unit. A hysteresis adaptive controller includes a main control MCU or embedded processor, an ADC acquisition circuit, an ultrasonic drive control interface, a proportional valve drive interface, a heating power control interface, a memory, a display and button module, and a power supply module.

[0120] hardware Model or type use Main control chip STM32H743, STM32F407, ESP32-S3 Collect sensor data, calculate the flavor absorption resistance coefficient, and output control commands. pressure sensor TE Connectivity M3200 Series This series of instruments measures pressure within a chamber and can be used for liquid or gas pressure measurement. It is suitable for applications involving steam, contaminated water, and mildly corrosive media. Temperature sensor PT100 / PT1000 stainless steel probes, such as OMEGA-type RTD probes It detects the temperature of the flavoring liquid or cavity wall for heating closed-loop control and conductivity temperature compensation; the OMEGA RTD probe typically uses a 100Ω platinum resistance element. Food thickness acquisition unit MaxBotix MB7389 HRXL-MaxSonar-WRMT, or a high-temperature resistant TOF ranging module. Installed inside the cavity cover, it detects the distance from the top of the food item; the MB7389 features 1mm resolution, 42kHz ranging, and analog / serial / pulse width output. conductivity sensor Atlas Scientific IndustrialConductivity Probe K 1.0 +EZO-EC Circuit For detecting the conductivity of seasoning liquids; the Atlas industrial-grade K1.0 conductivity probe features a 3 / 4-inch NPT thread and integrates a PT1000 temperature sensor for easy temperature compensation. Turbidity sensor DFRobot SEN0189, or industrial online turbidity probe For detecting the turbidity of soup liquids, the SEN0189 is powered by 5V, has analog / digital output, and a response time of less than 500ms. However, its probe top is not waterproof, making it more suitable for placement in an isolated detection branch. Liquid level detection unit OMRON E2K-L series capacitive liquid level sensor For detecting seasoning liquid levels or preventing dry burning; the E2K-L can be used for level detection in non-metallic pipes, powered by 12~24VDC, with a repeatability of ±0.2mm. Proportional pressure regulation / relief unit SMC ITV series electric proportional pressure regulating valve, or steam-resistant proportional pressure relief valve Used to generate hyperbolic pressure breathing ripples; the SMC ITV series are electrical proportional pressure regulators controlled by electrical signals, with some models supporting 24VDC, M12 connection, 12-bit I / O, and IP65 protection. Low-frequency ultrasonic transducer 20kHz, 28kHz, 40kHz piezoelectric ceramic transducers This creates cavitation-type low-frequency effects, which are used for micro-perturbations on the surface of food ingredients. Medium frequency ultrasonic transducer 60kHz, 80kHz, 100kHz piezoelectric ceramic transducers A mass transfer transition sound field is formed, weakening the boundary layer on the surface of the food. High-frequency ultrasonic transducer 150kHz, 200kHz, 300kHz or 500kHz piezoelectric transducers This creates a penetrating, high-frequency effect, promoting the diffusion of the seasoning liquid into the food. Ultrasonic drive power supply DDS sweep frequency driver board + MOSFET power amplifier + impedance matching network Control frequency, power, duty cycle, and transducer overlap switching

[0121] The sealed stewing chamber is connected to the heating and exhaust assembly. An electric heating plate is installed at the bottom of the sealed stewing chamber, which is attached to the bottom of the inner pot via a heat-conducting base plate. A ring-shaped heating strip or flexible heating film can be installed on the side walls to reduce temperature differences. An exhaust channel is located on the top of the chamber lid, and an electrically controlled exhaust valve and a splash-proof liquid-blocking structure are installed sequentially on the exhaust channel. Electrically, the electric heating plate and side wall heating elements are connected to a damping adaptive controller via a solid-state relay or a thyristor power adjustment module. The controller adjusts the heating power based on feedback from temperature and pressure sensors to achieve heating and exhaust, gradual pressure increase, and stable pressure cooking. The sealed stewing chamber is connected to the controllable pressure regulating assembly. A pressure relief port is provided on the sealed chamber lid, which is sequentially connected to a proportional pressure relief valve, a pressure buffer chamber, and an exhaust outlet. The pressure buffer chamber is used to weaken the pressure impact during pressure relief and prevent soup splashing. A pressure sensor is installed on the top of the chamber lid or chamber body and communicates with the gas phase space inside the chamber. In terms of electrical connection, the pressure sensor outputs analog voltage, digital I²C / SPI signal, or 4-20mA signal to the controller; the proportional pressure relief valve is controlled by the controller outputting PWM, 0-10V, or 4-20mA signals for opening degree. The controller generates a hyperbolic pressure breathing fluctuation through "pressure boosting by the boosting unit + slight pressure relief by the proportional pressure relief valve". For the connection between the sealed stewing chamber and the sweeping ultrasonic component, the low-frequency cavitation transducer is preferably installed on the outer bottom or lower side wall of the sealed stewing chamber, transmitting acoustic energy to the seasoning liquid through metal coupling; the mid-frequency mass transfer transducer is installed on the side wall of the chamber; and the high-frequency penetrating transducer is installed on the inner side or upper side wall of the chamber cover. A heat-resistant sealing gasket and an acoustic coupling layer are installed between each transducer and the chamber to ensure that acoustic energy is transmitted to the seasoning liquid without damaging the chamber seal. Electrically, each transducer is connected to the ultrasonic drive power supply. The ultrasonic drive power supply receives frequency control, power control, duty cycle control, and channel selection signals output by the hysteresis adaptive controller. If a wideband transducer is used, the controller controls its frequency to continuously sweep and change through the DDS sweep frequency signal; if multiple fixed frequency transducers are used, the controller switches the power overlay to make the low-frequency, medium-frequency and high-frequency transducers work sequentially or in an overlapping manner.

[0122] The food thickness acquisition unit is installed inside the cavity cover, with the detection direction facing the upper surface of the food; its output is connected to the controller's digital interface or analog acquisition interface. Due to the high temperature and humidity inside the cavity, the thickness detection unit is preferably located outside the heat-insulated transparent detection window, or a heat-resistant encapsulated probe is used. It is recommended that the conductivity sensor and turbidity sensor not be directly exposed in the high-disturbance area of ​​the main stewing cavity, but rather placed in the seasoning liquid detection branch. Specifically, a liquid intake port is set at the lower side of the sealed stewing cavity, connected to a miniature heat-resistant detection cavity. The conductivity sensor, temperature compensation sensor, and turbidity sensor are sequentially installed inside the detection cavity, and the outlet of the detection cavity returns to the sealed stewing cavity. This reduces the influence of food debris, air bubbles, and localized uneven concentration on the detection results. The ultrasonic echo transceiver unit is installed on the side wall of the cavity or inside the cavity cover, with its detection direction facing the main food placement area. This unit emits detection pulses during the interval when the sweep frequency ultrasonic component stops outputting, and receives echo signals from the interface between the food and seasoning liquid and the internal tissue interface of the food. Its output is connected to the controller's high-speed sampling circuit or dedicated ultrasonic echo processing circuit.

[0123] In some embodiments, the main controller is an STM32H743 or STM32F407; pressure detection is achieved using a TE M3200, with a recommended range of 0–300 kPa or 0–500 kPa gauge pressure; temperature detection uses a PT100 / PT1000 stainless steel probe installed in the seasoning liquid detection branch; food thickness detection uses a heat-resistant ranging unit inside the cavity cover, or a MaxBotix MB7389 with a heat-insulated detection window; conductivity detection uses an Atlas Scientific Industrial Conductivity Probe K1.0 + EZO-EC circuit; turbidity detection uses an industrial online turbidity probe, or a SEN0189 placed in a low-temperature isolated detection branch; and liquid level detection uses an OMRON probe. The E2K-L series is installed on the outside of the non-metallic detection tube; pressure regulation is achieved through a proportional pressure relief valve, a pressure buffer chamber, and a mechanical safety pressure relief valve; ultrasonic operation is achieved through a 40kHz low-frequency transducer, an 80kHz medium-frequency transducer, and a 200kHz high-frequency transducer, each controlled by an independent drive channel; heating is achieved through an 800-1500W bottom heating plate + a 100-300W side wall auxiliary heating strip; safety components include a temperature control fuse, a mechanical pressure limiting valve, a cover locking switch, anti-dry-burn protection, and a leakage protection module.

[0124] In one specific embodiment, a bottom heating plate is provided at the bottom of the sealed stewing chamber, and side wall auxiliary heating elements are provided on the side walls of the sealed stewing chamber. The sealed chamber cover is provided with an exhaust channel and a pressure relief port. The pressure relief port is sequentially connected to a proportional pressure relief valve and a pressure buffer chamber, and a pressure sensor is connected to the gas phase space of the sealed stewing chamber. The sweep-frequency ultrasonic component includes a low-frequency cavitation transducer installed at the bottom of the chamber, a medium-frequency mass transfer transducer installed on the side wall of the chamber, and a high-frequency permeation transducer installed on the chamber cover or upper side wall. Each transducer is connected to an ultrasonic drive power supply. A food thickness acquisition unit is installed inside the sealed chamber cover, a conductivity sensor and a turbidity sensor are installed in the seasoning liquid detection branch, and an ultrasonic echo transceiver unit is installed on the side wall of the chamber facing the food area. A hysteresis adaptive controller is electrically connected to the heating exhaust component, the proportional pressure relief valve, the pressure sensor, the sweep-frequency ultrasonic component, the conductivity sensor, the turbidity sensor, and the ultrasonic echo transceiver unit, respectively, to output heating power, pressure relief opening, ultrasonic frequency, ultrasonic power, and ultrasonic duty cycle control signals based on the food detection data.

[0125] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0126] (1) This invention uses a food ingredient detection component to acquire real-time changes in the conductivity of the seasoning liquid and changes in the attenuation of the ultrasonic echo. A flavor penetration resistance coefficient generation module generates a flavor penetration resistance coefficient that characterizes the difficulty of the seasoning liquid continuing to migrate into the food, so that the system no longer relies solely on a fixed time or fixed pressure program for stewing. When a decrease in the rate of decrease in conductivity and the rate of decrease in echo attenuation are detected, it indicates that the migration of the seasoning liquid into the interior is hindered. The system then promotes the continued entry of the seasoning liquid into the pores and fiber gaps of the food by extending the hyperbolic pressure breathing fluctuation time and increasing the proportion of high-frequency sweep frequency, thereby improving the problem of flavor penetration on the surface of thick meat, bean products and root vegetables while the core is bland.

[0127] (2) This invention employs a hyperbolic asymptotic pressure-increasing method with a fast initial pressure followed by a slow pressure increase. This allows the intracavitary pressure to rapidly establish mass transfer driving force in the initial stage, and then gradually approach the target pressure in the later stage, avoiding the sudden compaction or damage to the surface of the food due to linear rapid pressure increase. At the same time, a hyperbolic pressure breathing fluctuation is formed near the target pressure, causing the pores inside the food to produce a gentle liquid absorption and retention effect during the small pressure increase and decrease process. The frequency sweeping ultrasound gradually shifts from cavitation-type low frequency to penetration-type high frequency, reducing the risk of surface breakage, soup turbidity, and fiber breakage caused by long-term low-frequency cavitation, making the flavor enhancement process more gradual, continuous, and controllable.

[0128] (3) The present invention is equipped with an adaptive correction module, an ingredient thickness correction module, and a tissue protection module. It can dynamically correct the target pressure, asymptotic pressure rise time, pressure breathing fluctuation period, and high-frequency sweep ratio based on information such as ingredient thickness, changes in flavor penetration resistance coefficient, abnormal turbidity of seasoning liquid, abnormal fluctuation of conductivity, and abrupt changes in ultrasonic echo. For thicker or denser ingredients, the system automatically extends the breathing fluctuation time and increases the proportion of penetrating high-frequency action; for fragile ingredients or situations where there is a risk of tissue damage, it limits the cavitation low-frequency output and reduces the pressure fluctuation amplitude, thereby improving the consistency of stewing results for different batches and types of ingredients.

[0129] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products, and therefore this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0130] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function, characterized in that, include: Sealed stewing chamber, heating and exhaust assembly, controllable pressure regulating assembly, sweep frequency ultrasonic assembly, food detection assembly, and resistance adaptive controller; The food detection component includes a food thickness acquisition unit, a conductivity sensor, a turbidity sensor, and an ultrasonic echo transceiver unit, used to acquire food thickness, seasoning liquid conductivity, seasoning liquid turbidity, initial ultrasonic echo, and real-time ultrasonic echo. The adaptive controller for retardation includes a flavor retardation coefficient generation module, a hyperbola cooperative trajectory generation module, and an adaptive correction module. The flavor penetration resistance coefficient generation module is used to generate a flavor penetration resistance coefficient based on the real-time conductivity decrease rate and the ultrasonic echo attenuation rate, and the flavor penetration resistance coefficient increases as the real-time conductivity decrease rate and the ultrasonic echo attenuation rate decrease. The hyperbolic collaborative trajectory generation module is used to control the controllable pressure regulating component and the frequency sweeping ultrasound component according to the ingestion blockage coefficient, so that the intracavitary pressure rises to the target pressure in a hyperbolic asymptotic manner with a fast initial pressure followed by a slow pressure later, and forms a hyperbolic pressure respiratory fluctuation around the target pressure. At the same time, the frequency sweeping ultrasound component migrates from cavitation type low frequency to permeation type high frequency in a continuous frequency sweep or multi-transducer overlapping switching mode. The hyperbolic pressure respiratory fluctuation is a periodic pressure rise and fall around the target pressure, and both the pressure rise slope and the pressure fall slope change with a fast initial pressure followed by a slow pressure later. The adaptive correction module is used to reduce the pressure ramp slope, prolong the hyperbolic pressure-respiratory fluctuation time and increase the proportion of high-frequency sweep when the ingestion resistance coefficient increases relative to the previous sampling cycle, and to stop the sweep ultrasound and switch to the stable pressure maturation state when the ingestion resistance coefficient is lower than the preset threshold within a preset number of consecutive sampling cycles.

2. The gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, The pressure control trajectory generated by the hyperbolic collaborative trajectory generation module includes an asymptotic pressure increase segment and a respiratory fluctuation segment. In the asymptotic pressure increase segment, the rate of pressure increase in the cavity gradually decreases with the increase of running time, so that the pressure gradually approaches the target pressure in a way that avoids pressure overshoot. In the respiratory fluctuation segment, the pressure in the cavity rises and falls periodically around the target pressure, and the pressure increase slope and pressure decrease slope in each cycle change from fast at the beginning to slow at the end.

3. The gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, The frequency sweeping ultrasound component includes a broadband transducer capable of covering 20–500 kHz, or includes a low-frequency cavitation transducer with an operating frequency of 20–45 kHz, a mid-frequency mass transfer transducer with an operating frequency of 45–120 kHz, and a high-frequency penetrating transducer with an operating frequency of 120–500 kHz. The hyperbolic frequency sweeping method is as follows: in the initial stage of the frequency sweep, the residence time in the cavitation-type low-frequency region of 20–45 kHz is relatively short and the frequency sweeping change rate is relatively large; in the middle stage of the frequency sweep, it passes through the mass transfer transition frequency region of 45–120 kHz; in the later stage of the frequency sweep, the residence time in the penetrating high-frequency region of 120–500 kHz increases and the frequency sweeping change rate decreases, so that the frequency sweeping ultrasound migrates from the cavitation-type low-frequency region through the mass transfer transition frequency region to the penetrating high-frequency region.

4. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, The flavor penetration resistance coefficient generation module uses the rate of change between the initial conductivity and the real-time conductivity of the seasoning liquid as a measure of the migration speed of the seasoning components, and the attenuation rate between the initial ultrasonic echo and the real-time ultrasonic echo as a measure of liquid absorption and tissue relaxation inside the food. The flavor penetration resistance coefficient generation module normalizes the measure of the migration speed of the seasoning components and the measure of liquid absorption and tissue relaxation inside the food, and then performs inverse weighted fusion on the normalized measure of the migration speed of the seasoning components and the measure of liquid absorption and tissue relaxation inside the food to generate the flavor penetration resistance coefficient.

5. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, When the inhalation resistance coefficient increases relative to the previous sampling period, the adaptive correction module performs at least one of the following control actions: reducing the pressure increase per unit time of the controllable pressure regulating component, reducing the frequency of hyperbolic pressure respiratory fluctuations and prolonging a single respiratory cycle, increasing the residence time of the sweep ultrasound in the permeable high-frequency region, reducing the output power in the cavitation low-frequency region, and increasing the pressure holding time near the target pressure.

6. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 2, characterized in that, The controllable pressure regulating component includes a pressure boosting unit, a proportional pressure relief valve, and a pressure buffer chamber. The pressure boosting unit is used to form an asymptotic pressure increase segment. The proportional pressure relief valve is used to form a hyperbolic pressure reduction process in the respiratory fluctuation segment according to the pressure relief opening signal output by the hysteresis adaptive controller. The pressure buffer chamber is used to weaken pressure abrupt changes, so that the pressure rise and fall amplitude in the respiratory fluctuation segment is kept within a preset proportional range of the target pressure.

7. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, The ultrasonic echo transceiver unit emits detection ultrasound during the interval when the sweep frequency ultrasonic component stops outputting, and receives echo signals from the interface between the food and the seasoning liquid and the interface between the internal tissues of the food, so as to avoid the sweep frequency ultrasonic output signal interfering with the calculation of the flavor absorption resistance coefficient.

8. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, The adaptive controller also includes a food thickness correction module; the food thickness correction module is used to correct the target pressure, hyperbolic asymptotic pressure rise time and high frequency sweep ratio according to the food thickness; the greater the food thickness, the longer the hyperbolic pressure respiratory fluctuation time near the target pressure, and the higher the high frequency sweep ratio.

9. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, The adaptive controller also includes a tissue protection module; the tissue protection module judges the risk of food tissue damage based on sudden changes in ultrasonic echo, abnormal fluctuations in conductivity and / or abnormal increases in the turbidity of the seasoning liquid. When the risk of food tissue damage exceeds the preset risk threshold, limit the cavitation-type low-frequency output, reduce the amplitude of hyperbolic pressure respiratory fluctuations, and / or prolong the hyperbolic pressure respiratory fluctuation cycle.

10. A gradient pressure stewing system with multi-frequency ultrasonic-assisted flavor infusion function according to claim 1, characterized in that, The pressure stabilization and maturation state is as follows: stop the frequency sweeping ultrasound or only retain the low-power penetrating high-frequency ultrasound, control the pressure inside the cavity to maintain within the maturation target pressure range, and determine the end of the pressure stabilization and maturation process based on the slowing down of real-time conductivity changes, the stabilization of ultrasound echo attenuation, and the flavor penetration resistance coefficient being lower than the preset threshold.

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