A domestic intelligent electric baking pan and a using method thereof

Abstract

The application discloses a household intelligent electric baking pan and a use method thereof, and belongs to the technical field of intelligent kitchen appliances. The household intelligent electric baking pan comprises the following steps: S1, an upper disc and a lower disc and a flexible hinge are arranged, and an annular waveguide type ultrasonic array is arranged on the edge of the lower disc; S2, food materials are placed, and the pre-tightening force of a spring is adjusted to make the upper disc flexibly contact the surface of the food materials; S3, heating is started, a heat field is modulated through an independent high-frequency duty cycle, and internal heat flow of the food materials is directionally guided; S4, ultrasonic assistance is started, and micro-vibration is conducted by using an annular array standing wave, thereby breaking a steam film effect and improving efficiency; and S5, an acoustic impedance feedback signal is acquired in real time, and doneness is determined according to signal mutation characteristics and cooking is stopped. The application realizes self-adaptive optimization of micro-environment pressure during cooking.

Description

Technical Field

[0001] This invention relates to the field of intelligent kitchen appliances, specifically to a household intelligent electric griddle and its usage method. Background Technology

[0002] In the process of cooking and processing food, conventional commercially available household electric griddles mainly rely on preset timers and simple dual-plate heating mechanisms. This traditional physical architecture and control strategy has significant limitations:

[0003] Uneven thermal resistance distribution and poor adaptability: The hinges of traditional equipment mostly adopt fixed shafts or simple elongated hole slide structures. When handling food of different thicknesses, it is impossible to achieve a dynamic balance between the thermal expansion force of the food and the clamping force of the upper plate. This means that for thicker food, rigid pressure can easily damage the food structure or restrict its expansion, while for thin food, it may result in poor contact, generating great thermal resistance and affecting heat conduction efficiency.

[0004] Low accuracy in determining the cooking endpoint: Existing technologies rely on a single logic for determining doneness, primarily depending on manually set time or simple feedback from the plate temperature. Since plate temperature is not equivalent to the core temperature of the food, and the physical properties of food with different moisture contents and initial temperatures vary greatly, relying solely on experience to time the cooking process is insufficient to accurately capture the physical points of protein denaturation or starch gelatinization, easily leading to overcooking or undercooking of the food, resulting in inconsistent cooking outcomes.

[0005] Limited boundary heat transfer efficiency: During the heating process, the evaporation of moisture from the food forms a steam film on the plate surface. As a gaseous medium, the steam film has extremely high thermal resistance, and traditional equipment lacks the physical means to break this film, resulting in low thermal energy utilization and a prolonged cooking cycle.

[0006] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a household smart electric griddle and its usage method to solve the problems mentioned in the background art. Specifically, the technical solution of this invention is as follows:

[0008] A household smart electric griddle and its usage method, including:

[0009] S1. An upper plate assembly, a lower plate assembly, and a flexible hinge mechanism are provided. A ring-shaped waveguide ultrasonic array is installed on the edge of the lower plate base of the lower plate assembly. The flexible hinge mechanism connects the upper plate assembly and the lower plate assembly. A nonlinear stiffness spring mechanism is provided inside the flexible hinge mechanism.

[0010] S2. Place the food to be processed on the cooking surface of the lower plate assembly, and adjust the initial prestress of the nonlinear stiffness spring mechanism to make the upper plate assembly and the food surface form a flexible contact.

[0011] S3. Start heating and execute dynamic asymmetric thermal field modulation. By independently modulating the power of the upper plate assembly and the lower plate assembly with high frequency duty cycle, the heat flow is guided directionally inside the food.

[0012] S4. During the heating process, ultrasonic assistance is activated. The standing wave generated by the ring-shaped guided ultrasonic array is used to transmit micro-vibrations to the bottom of the food through the lower plate assembly, so as to break the vapor film effect at the bottom of the food and improve the heat conduction efficiency.

[0013] S5. Perform online cooking monitoring, acquire the acoustic impedance feedback signal of the ring-shaped guided ultrasonic array in real time, determine the cooking status of the food based on the abrupt change characteristics of the acoustic impedance feedback signal, and stop cooking.

[0014] Preferably, step S3 includes:

[0015] The control system outputs a pulse width modulation signal with a preset carrier frequency to independently adjust the heat power distribution ratio between the upper and lower plates according to the type of food.

[0016] Preferably, step S4 includes:

[0017] The annular guided ultrasonic array is installed on the cold end of the lower plate assembly using a ceramic heat insulation layer. The ultrasonic excitation frequency generated by the annular guided ultrasonic array causes the cooking surface of the lower plate assembly to produce a micron-level amplitude.

[0018] Preferably, step S5 includes:

[0019] The current feedback curve of the ring-shaped guided ultrasonic array is monitored. When the acoustic impedance feedback signal reaches the preset phase transition threshold, it is determined that the protein denaturation or starch gelatinization of the food has been completed, and a cooking completion signal is output.

[0020] Preferably, in step S2:

[0021] The flexible hinge mechanism passively adjusts the pressing force of the upper plate assembly on the food through the nonlinear stiffness spring mechanism according to the expansion displacement of the food during the heating process, thereby maintaining thermal contact while forming a steam venting micro-gap.

[0022] A household smart electric griddle includes:

[0023] The upper and lower plate components are each equipped with independent heating elements;

[0024] A flexible hinge mechanism is connected between the upper plate assembly and the lower plate assembly, and its interior integrates a nonlinear stiffness spring mechanism with nonlinear stiffness characteristics.

[0025] An ultrasonic generating assembly includes a ring-shaped waveguide ultrasonic array mounted on the edge of the lower plate assembly and a ceramic heat insulation layer disposed between the ring-shaped waveguide ultrasonic array and the lower plate substrate.

[0026] The control system is electrically connected to the heating element and the ring-shaped waveguide ultrasonic array, respectively, and is used to realize power modulation and acoustic impedance signal acquisition.

[0027] Preferably, the material of the lower plate assembly is aluminum alloy waveguide medium, and the annular waveguide ultrasonic array is installed on the cold end of the base of the lower plate assembly through the ceramic heat insulation layer.

[0028] Preferably, the prestress adjustment end of the nonlinear stiffness spring mechanism is exposed outside the flexible hinge mechanism for manually or automatically matching the initial thickness of different types of ingredients.

[0029] Preferably, the control system includes a multi-channel data acquisition module, which is connected to a temperature sensor embedded in the center of the upper and lower plate components.

[0030] Preferably, the annular guided wave ultrasonic array forms a uniformly distributed standing wave field on the cooking surface of the lower plate assembly, and the amplitude of the standing wave field is sufficient to overcome the adhesion between the food and the plate surface.

[0031] Compared with the prior art, the present invention has the following improvements and advantages:

[0032] 1. The equipment can match the initial pressure through the prestress adjustment end according to the initial height of different ingredients such as dough or thick-cut meat. During the heating process, the flexible hinge passively adjusts the clamping force according to the expansion displacement of the ingredients, which not only ensures the physical contact required for heat conduction, but also discharges supersaturated steam through the steam discharge micro gaps to prevent condensate backflow from affecting the taste, thus achieving adaptive optimization of the cooking micro-environment pressure.

[0033] 2. A microprocessor with multi-channel PWM output is used to generate pulse width modulation signals from 1Hz to 10Hz. These signals, combined with temperature signals acquired by a multi-channel data acquisition module, enable asymmetric heat distribution. For example, when cooking steak, a high duty cycle in the lower plate promotes the Maillard reaction, while a low output in the upper plate maintains internal moisture. This allows for the directional guidance of heat flow from the high-temperature zone to the low-temperature zone within the food, improving thermal efficiency without increasing hardware costs.

[0034] 3. Ultrasonic excitation generates micron-level amplitudes of 10 to 20 microns on the cooking surface of the lower plate assembly, forming a uniformly distributed standing wave field on the plate surface. This high-frequency vibration breaks the vapor film effect at the bottom of the food, turning indirect gaseous heat transfer back into direct solid-solid contact heat transfer, significantly shortening cooking time. At the same time, the local acceleration generated by the standing wave field overcomes the adhesion between the food and the plate surface, enabling quasi-suspended cooking with little or no oil, reducing cleaning difficulty;

[0035] 4. Since the ingredients are part of the sound path, protein denaturation or starch gelatinization within them can cause abrupt changes in density and elastic modulus. This solution extracts the abrupt change characteristics of acoustic impedance and automatically stops cooking when the signal crosses a preset physical phase transition threshold. This physical feedback-based determination method changes the ambiguity of traditional experience-based timing, ensuring the scientific validity and reproducibility of cooking results for ingredients in different initial states. Attached Figure Description

[0036] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0037] Figure 1 This is a schematic diagram of the overall external structure of an electric griddle;

[0038] Figure 2 This is a schematic diagram of the back structure of an electric griddle;

[0039] Figure 3 This is a structural diagram of the lower plate assembly;

[0040] Figure 4 This is a schematic diagram of the process flow of the method of the present invention.

[0041] In the figure: 100, upper plate assembly; 110, nonlinear stiffness spring mechanism; 120, flexible hinge mechanism; 200, lower plate assembly; 210, ring-shaped waveguide ultrasonic array; 220, ceramic heat insulation layer; 230, lower plate base; 300, control system. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0043] Example 1:

[0044] Please see Figure 1-4 This invention provides a household smart electric griddle and its usage method, including:

[0045] S1. An upper plate assembly 100, a lower plate assembly 200, and a flexible hinge mechanism 120 are provided. The lower plate assembly 200 has a ring-shaped waveguide ultrasonic array 210 installed on the edge of the lower plate base 230. The flexible hinge mechanism 120 connects the upper plate assembly 100 and the lower plate assembly 200. A nonlinear stiffness spring mechanism 110 is provided inside the flexible hinge mechanism 120.

[0046] S2. Place the food to be processed on the cooking surface of the lower plate assembly 200, and adjust the initial prestress of the nonlinear stiffness spring mechanism 110 to make the upper plate assembly 100 and the food surface form a flexible contact.

[0047] S3. Start heating and execute dynamic asymmetric heat field modulation. By independently modulating the power of the upper plate component 100 and the lower plate component 200 at high frequency, the heat flow is guided directionally inside the food.

[0048] S4. During the heating process, ultrasonic assistance is activated. The standing wave generated by the ring-shaped waveguide ultrasonic array 210 is transmitted to the bottom of the food through the lower plate assembly 200 to break the vapor film effect at the bottom of the food and improve the heat transfer efficiency.

[0049] S5. Perform online cooking monitoring, acquire the acoustic impedance feedback signal of the ring-shaped guided wave ultrasonic array 210 in real time, determine the cooking status of the food based on the abrupt change characteristics of the acoustic impedance feedback signal, and stop cooking.

[0050] In the embodiments of the above-mentioned method of using a household smart electric griddle, the starting point of the technical means lies in the coordinated arrangement of the hardware physical layer. In view of the technical defects of the existing traditional electric griddles such as the SLG6028 prototype in terms of uneven thermal resistance distribution when processing ingredients of different thicknesses and low accuracy due to the reliance on timers to determine the cooking endpoint, this embodiment introduces high-frequency mechanical vibration into the cooking environment by arranging a ring-shaped guided ultrasonic array 210 on the edge of the lower plate base 230 of the lower plate assembly 200. This arrangement avoids the extreme high temperature zone directly below the heating plate. By using the aluminum alloy substrate of the lower plate assembly 200 as a waveguide medium, the ultrasonic energy is evenly distributed on the cooking surface in the form of standing waves. When the operator performs step S1, the upper plate assembly 100 and the lower plate assembly 200 are physically connected through a flexible hinge mechanism 120. The nonlinear stiffness spring mechanism 110 integrated inside the flexible hinge mechanism 120 provides the upper plate with adjustable degrees of freedom. In the operation process of step S2, the introduction of the nonlinear stiffness spring mechanism 110 makes the equipment no longer a rigid pressing. Instead, according to the initial height of different ingredients such as leavened bread or thick-cut meat, the prestress is adjusted manually or automatically, so that the upper plate assembly 100 covers the surface of the ingredients with a moderate pressure. The significance of this flexible contact is that it can ensure the physical contact required for heat conduction, while not damaging the internal structure of the ingredients or restricting their space for thermal expansion due to excessive rigid pressure.

[0051] Entering the heating stage of step S3, the control system 300 begins operation. In this embodiment, the control system 300 uses an STM32F103VCT6 microcontroller as its core computing unit. Dynamic asymmetric thermal field modulation is executed through power drive circuits independently connected to the heating elements of the upper plate assembly 100 and the lower plate assembly 200. Specifically, the power drive is achieved using an IR2110 driver chip in conjunction with a high-power MOSFET. A full-bridge rectifier circuit is integrated into the power circuit to convert mains power into high-voltage DC power before high-frequency duty cycle modulation. In this operating mode, the heating power of the upper and lower plates is no longer synchronized, but rather asymmetric heat input is achieved based on the real-time state of the food. For example, when cooking steak, the lower plate power can be set to a higher duty cycle to form the caramelized layer required for the Maillard reaction, while the upper plate power maintains a lower output through high-frequency modulation to preserve internal moisture. This achieves directional guidance of heat flow from the high-temperature zone to the low-temperature zone within the food.

[0052] In step S4, the ring-shaped guided ultrasonic array 210 is activated. The ultrasonic array consists of multiple sets of PZT-4 piezoelectric ceramic transducers, installed at the cold end of the lower plate assembly 200. When the ultrasonic energy is turned on, the cooking surface of the lower plate assembly 200 will generate micron-level micro-vibrations due to the presence of standing waves. The physical significance of this micro-vibration is that it can break the vapor film formed on the plate surface due to the evaporation of moisture from the food. The vapor film, as a gaseous medium, has a large thermal resistance. The micro-vibration breaks this vapor film through mechanical energy. At the same time, the shear force generated by the standing wave field on the cooking surface overcomes the intermolecular adhesion force between the protein components in the food and the aluminum alloy surface, realizing a quasi-suspended cooking state. This results in a significant increase in the heat conduction efficiency of the food in direct contact with the metal plate surface. This process not only shortens the cooking time, but also allows heat to penetrate deeper into the food fibers due to the cavitation effect of the sound field on local moisture.

[0053] In step S5, the system utilizes the acoustic impedance feedback characteristics of the ring-shaped guided ultrasonic array 210 to monitor cooking doneness. As proteins denature or starches gelatinize within the food, the acoustic impedance of the food changes significantly. The control system 300 monitors the current feedback curve in the ultrasonic drive circuit in real time, extracting the abrupt change characteristics of the acoustic impedance. When the acoustic impedance signal crosses a preset physical phase transition threshold, the system determines that the food has reached the ideal degree of cooking and automatically cuts off the power. This physical feedback-based determination method changes the ambiguity of traditional experience-based timing, enabling consistent cooking results for foods with different moisture contents and initial temperatures.

[0054] The steps in S3 include:

[0055] The control system 300 outputs a pulse width modulation signal with a preset carrier frequency to independently adjust the heat power distribution ratio between the upper and lower plates according to the type of food.

[0056] In the embodiments supporting the above, the method of control system 300 for precise control of the thermal field through refined power distribution is described in detail. The STM32F103VCT6 controller selected by control system 300 has multiple advanced timers and can generate pulse width modulation signals with a frequency range of 1Hz to 10Hz. For different types of cooking objects, such as high-moisture batter or high-fiber meat, their thermophysical properties are completely different. Batter undergoes rapid phase change and volume expansion during heating, while meat exhibits more water loss and protein shrinkage.

[0057] During the actual execution process, the control system 300 internally stores a heat power allocation table for different ingredients;

[0058] This allocation table is essentially a multidimensional thermal resistance network coupling model, which takes into account the thickness of the food ingredients. Moisture content Using the input variable, the thickness of the caramelized layer is calculated by simulating the vertical heat conduction path within the food. With internal ripeness The power time series required for optimal balance guides the real-time output of the pulse width modulation signal;

[0059] This model logically represents the dynamic heat transfer path from the upper and lower heating elements, through the metal plate surface, contact boundary thermal resistance, the charred layer on the food surface, to the internal moist core. By simulating the change in thermal diffusivity under different moisture contents, the model can calculate and compensate for the increase in thermal resistance caused by moisture loss in real time, thereby outputting the optimal duty cycle command. The specific calculation logic is based on the variational correction of the one-dimensional steady-state heat conduction equation. ,in, The total heat flow per unit time, in units of ; This refers to the real-time temperature difference between the heating plate and the core of the food; considering the overall thermal resistance. The thickness and thermal conductivity of each layer of medium Decide;

[0060] The model is corrected based on real-time temperature feedback. The curve showing the change in water loss, and the specific compensation logic follow the formula. ,in, The initial thermal conductivity of the food. This is a moisture thermal resistance correction factor. and The system measures the real-time and initial moisture content of the ingredients to dynamically compensate for the nonlinear increase in boundary thermal resistance. The control system maps the calculated values ​​to the duty cycle output command of the PWM controller in real time, and precisely adjusts the instantaneous heat power of the heating element by changing the high-frequency pulse width to ensure that the heat flux density matches the real-time physical phase change stage of the ingredients.

[0061] When the operator selects a specific mode, the controller outputs two independent pulse width modulation (PWM) signals. The first signal acts on the heating element of the upper assembly 100, and the second signal acts on the heating element of the lower assembly 200. By adjusting the duty cycle percentage of these two signals, asymmetrical heat distribution can be achieved.

[0062] For example, when processing a 3cm thick tomahawk steak, the system sets the duty cycle of the bottom plate to 80% to ensure that the bottom can generate enough high temperature to caramelize the surface; while the duty cycle of the top plate is dynamically adjusted between 30% and 50% based on temperature feedback to prevent the top from hardening too early and preventing heat from being conducted to the center.

[0063] The significance of this independent adjustment lies in its breaking through the limitations of traditional electric griddles that heat up synchronously. It allows the device to simulate the flipping effect of open-flame cooking without manual intervention. By controlling the carrier frequency settings of the 300 system, mechanical fatigue caused by frequent relay operation is effectively avoided. Stepless power adjustment using electronic switching devices ensures stable temperature fluctuations in the heating plate. This power distribution based on the physical characteristics of the ingredients makes the vertical heat gradient distribution more consistent with the natural cooking process, thus improving heat utilization efficiency through algorithmic logic without increasing hardware costs.

[0064] The steps in S4 include:

[0065] A ring-shaped waveguide ultrasonic array 210 is installed on the cold end of the lower plate assembly 200 using a ceramic heat insulation layer 220. The ultrasonic excitation frequency generated by the ring-shaped waveguide ultrasonic array 210 causes the cooking surface of the lower plate assembly 200 to produce a micron-level amplitude.

[0066] In the embodiments supporting the above, the structural safety and physical effects achieved in the acoustic-thermal synergy are described in detail. The cooking surface of a household electric griddle typically needs to achieve... to The high-temperature range is crucial, and conventional piezoelectric transducers experience irreversible demagnetization failure when their Curie point temperature is exceeded. To resolve this engineering dilemma, this embodiment incorporates a 2mm to 5mm thick ceramic heat insulation layer 220 between the annular waveguide ultrasonic array 210 and the lower plate base 230 of the lower plate assembly 200. The ceramic heat insulation layer 220 is made of alumina ceramic material with low thermal conductivity and high sound transmission efficiency. The acoustic impedance of alumina ceramic material is... Should meet ,in The acoustic impedance of the lower aluminum alloy substrate is used to achieve efficient coupling and transmission of acoustic energy.

[0067] In terms of mechanical assembly structure, the annular guided ultrasonic array 210 is pressed onto one side of the ceramic heat insulation layer 220 by bolt pre-tightening force, while the other side of the ceramic heat insulation layer 220 is tightly attached to the cold end edge of the lower plate base 230. This cold end installation method utilizes the physical span from the center of the heat source and the thermal resistance of the ceramic material to ensure that the working environment temperature of the piezoelectric ceramic is maintained below 80 degrees Celsius. At the same time, the acoustic impedance of the alumina ceramic is matched with the aluminum alloy lower plate assembly 200, ensuring that the ultrasonic energy can efficiently penetrate the heat insulation medium and enter the guided wave medium.

[0068] When the driving voltage is applied to the ring-shaped guided ultrasonic array 210, the resulting excitation frequency is controlled between 28kHz and 40kHz. This frequency range can generate significant mechanical resonance, which is transmitted to the cooking surface through the aluminum alloy structure of the lower plate assembly 200. According to the principle of interference, the sound waves are reflected on the plate surface to form a stable standing wave field. Measurements by the multi-channel data acquisition module show that the normal amplitude of the cooking surface remains between 10 and 20 micrometers. Although this micrometer-level displacement is difficult to perceive with the naked eye, the resulting local acceleration is sufficient to overcome the intermolecular forces between the food and the plate surface. When the steam at the bottom of the food expands due to heat and attempts to form a continuous gas film, this high-frequency vibration breaks the gas film through sound pressure, causing heat conduction to return from indirect gas-to-gas heat transfer to direct solid-to-solid contact heat transfer. This method not only avoids high-temperature losses in the transducer but also improves the boundary heat transfer conditions of the cooking surface through purely physical mechanical vibration.

[0069] The steps in S5 include:

[0070] The current feedback curve of the ring-guided ultrasonic array 210 is monitored. When the acoustic impedance feedback signal reaches the preset phase transition threshold, it is determined that the protein denaturation or starch gelatinization inside the food has been completed, and a cooking completion signal is output.

[0071] In the embodiments supporting the above, the intelligent cookedness determination logic is described in detail. Traditional determination methods often rely on detecting the temperature of the pan surface, but the pan surface temperature is not entirely equivalent to the core temperature inside the food. Since the ring-shaped waveguide ultrasonic array 210 is acoustically coupled to the food, the food itself becomes part of the sound path. During cooking, the mechanical properties of the food undergo drastic changes. For example, during the transition from raw to cooked meat, the muscle fibers change from a loose state to a tight state, and the internal moisture content also decreases.

[0072] During step S5, the control system 300 acquires the loop current signal driving the ultrasonic array in real time via a precision current transformer. Changes in acoustic impedance are directly reflected in the electrical impedance of the ultrasonic transducer, thereby altering the amplitude and phase of the current. The control system 300 records the current feedback curve at a sampling frequency of 100 times per second through its internal analog-to-digital conversion channel. In the initial stage of cooking, due to the high water content and soft texture of the ingredients, the acoustic impedance is relatively high, and the feedback current waveform exhibits a stable low amplitude state.

[0073] As heating progresses, when the food reaches the temperature point where proteins denature, the density and elastic modulus of the food undergo a sudden change, leading to an increase in the sound transmission efficiency along the sound path. At this physical moment, the acoustic impedance feedback signal will exhibit a significant step-like jump or peak shift. The logic program within the controller will compare the real-time signal change rate with the phase transition threshold preset in the EEPROM memory.

[0074] This phase transition threshold is based on the specific slope inflection point of the acoustic impedance curve caused by a nonlinear abrupt change in the shear modulus of a particular food during protein denaturation or starch gelatinization. This inflection point is identified by the first derivative of the current feedback envelope. Determine, when When the rate of change exceeds a preset change threshold for three consecutive sampling periods, it is used to characterize the physical critical state of food changing from raw to cooked.

[0075] Once the signal slope exceeds the set range and remains at the preset time step, the system determines that the food has completed its core phase transition, thus meeting the cooking requirements. The specific processing flow is as follows: The control system 300 acquires the real-time driving current signal of the ring-guided ultrasonic array 210 through a current transformer; it extracts the current envelope through high-frequency sampling and filters out ripple interference from the heating pulse; then, it calculates the first derivative of the current envelope to identify impedance transition points; when this transition characteristic satisfies the preset characteristic vector for three consecutive sampling cycles, it outputs the cooking result. At this point, the control system 300 immediately stops heating and drives a buzzer or LCD screen to display a cooking completion signal. The advantage of this judgment logic is that it does not rely on the time set by the operator, but directly performs real-time non-destructive testing of the physical state of the food, thereby ensuring the scientific validity and reproducibility of the cooking results.

[0076] In step S2:

[0077] The flexible hinge mechanism 120 passively adjusts the pressing force of the upper plate assembly 100 on the food through the nonlinear stiffness spring mechanism 110 according to the expansion displacement of the food during the heating process, thereby forming a steam venting micro-gap while maintaining thermal contact.

[0078] In the embodiments supporting the above, the adaptive fit between mechanical structure and thermodynamics is described in detail. The hinge of a traditional electric griddle usually adopts a fixed shaft or a simple elongated slide structure, which cannot achieve a dynamic balance between expansion force and clamping force. The flexible hinge mechanism 120 in this embodiment contains a nonlinear stiffness spring mechanism 110, which has a variable cross-section design, so that its stiffness increases exponentially with the increase of deformation.

[0079] In the practical application of step S2, when the operator places a leavened dough and closes the lid, the upper plate assembly 100 contacts the dough surface due to its own weight and the initial prestress of the spring. As heating proceeds, the carbon dioxide and water vapor inside the leavened dough expand due to heat, generating an upward thrust. At this time, the flexible hinge mechanism 120 begins to function. After sensing a small expansion displacement, the nonlinear stiffness spring mechanism 110 automatically generates a corresponding reverse compressive force. Due to its nonlinear characteristics, the resistance provided by the spring is minimal in the initial stage of expansion, allowing the ingredients to grow freely, which ensures the fluffiness of the dough's internal structure.

[0080] The initial prestress refers to the static pressure applied to the nonlinear stiffness spring mechanism 110 by the adjustment end before cooking begins. Its value is positively correlated with the thickness of the food and aims to eliminate the air thermal resistance gap between the upper plate and the food.

[0081] As the displacement increases, the spring stiffness gradually increases, preventing the upper plate assembly 100 from being completely pushed open and causing a large amount of heat loss. A more ingenious design lies in the fact that, in this dynamic equilibrium state, the sealing edges of the upper plate assembly 100 and the lower plate assembly 200 will form a micro-gap with a width between 0.1mm and 0.3mm due to this flexible displacement. The physical significance of this micro-gap is that it can discharge supersaturated water vapor precipitated on the surface of the food in real time, preventing condensate from flowing back onto the plate and causing the food to soften. This passive adjustment mechanism does not require expensive sensors and servo motors; it relies solely on the physical characteristics of the mechanical structure to achieve adaptive control of the cooking microenvironment pressure, maintaining efficient heat contact while also taking into account the humidity requirements for the texture of the food.

[0082] Example 2:

[0083] Please see Figure 1-3 A household smart electric griddle, comprising:

[0084] The upper plate assembly 100 and the lower plate assembly 200 are each equipped with independent heating elements;

[0085] A flexible hinge mechanism 120 is connected between the upper plate assembly 100 and the lower plate assembly 200, and a nonlinear stiffness spring mechanism 110 with nonlinear stiffness characteristics is integrated inside it.

[0086] The ultrasonic generating assembly includes a ring-shaped waveguide ultrasonic array 210 installed on the edge of the lower plate assembly 200 and a ceramic heat insulation layer 220 disposed between the ring-shaped waveguide ultrasonic array 210 and the lower plate substrate.

[0087] The control system 300 is electrically connected to the heating element and the ring-shaped waveguide ultrasonic array 210, respectively, and is used to realize power modulation and acoustic impedance signal acquisition.

[0088] The above embodiments provide a systematic description of the structural integration of the entire device. This household smart electric griddle is physically divided into four core modules that work together to execute the aforementioned advanced cooking methods. The upper plate assembly 100 and the lower plate assembly 200 constitute the main heat exchange components. Each assembly contains an electric heating element with a resistance of 20Ω to 40Ω. These two heating elements are electrically connected in parallel to the mains power supply, but their current flow is managed by the control system 300 through two independent sets of solid-state relays, thus achieving physically independent thermal fields.

[0089] The flexible hinge mechanism 120 connecting the two heating plates is key to achieving physical self-adaptation. The internally integrated nonlinear stiffness spring mechanism 110 uses a double-cone helical spring, whose mechanical response curve can well simulate the mechanical needs of food expansion. The ultrasonic generator component represents a new dimension of energy introduction. The annular waveguide ultrasonic array 210 is not simply attached, but connected to the lower plate assembly 200 through a specific acoustic coupling structure. To protect the core piezoelectric material, a ceramic heat insulation layer 220 is cleverly placed between the two.

[0090] The control system 300, acting as the central nervous system, is connected to the heating element and ultrasonic array via cable bundles. The controller is powered by a switching power supply, capable of adapting to voltage fluctuations from 180V to 240V. Through its internal analog-to-digital converter interface, the control system 300 can capture impedance changes in the ultrasonic circuit in real time and convert them into logical criteria for cooking doneness determination. This device design changes the traditional product's single-function nature and lack of feedback, providing a highly reliable hardware platform for home cooking through deep integration of mechanical, acoustic, and thermal dimensions.

[0091] The lower plate assembly 200 is made of aluminum alloy waveguide medium, and the ring waveguide ultrasonic array 210 is installed on the cold end of the base of the lower plate assembly 200 through the ceramic heat insulation layer 220.

[0092] In the embodiments supporting the above, the impact of material selection and thermal management on acoustic efficiency is explained in detail. The lower plate assembly 200 is made of aluminum alloy not only because of its excellent thermal conductivity, but also because aluminum alloy has a low acoustic attenuation rate in the ultrasonic band at around 30kHz. This material characteristic makes aluminum alloy an ideal waveguide medium, ensuring that mechanical waves excited from the cold end of the base can be transmitted over long distances to the center of the plate without losing too much energy.

[0093] In its specific physical construction, the lower plate assembly 200 is designed with a geometry exhibiting a specific mass effect. A ring-shaped guided ultrasonic array 210 is mounted on the cold end of the base, away from the central axis of the heat source. Since the central region of the lower plate assembly 200 experiences the highest temperature during cooking, a natural cold end region is formed at the base edge through the natural distribution of the heat conduction gradient. The ceramic insulation layer 220 is installed here, maximizing passive heat dissipation by utilizing the ambient temperature difference.

[0094] During installation, to ensure the continuity of acoustic impedance, an ultrasonic coupling adhesive was applied between the ceramic insulation layer 220 and the aluminum alloy interface. This coupling adhesive maintains a stable elastic modulus at high temperatures. This design achieves physical isolation between thermal and acoustic energy, leveraging both the advantages of aluminum alloy as a highly efficient heat conductor and its potential as an acoustic waveguide. This cold-end mounting structure trades space for temperature stability, ensuring the consistency of ultrasonic performance during long-term continuous operation and significantly improving the mean time between failures (MTBF) of the transducer array.

[0095] The prestress adjustment end of the nonlinear stiffness spring mechanism 110 is exposed to the outside of the flexible hinge mechanism 120 for manually or automatically matching the initial thickness of different types of ingredients.

[0096] In the embodiments supporting the above, the adjustment logic between user interaction and mechanical adaptation is described in detail. Since different ingredients have different sensitivities to initial pressure, the nonlinear stiffness spring mechanism 110 is designed as a prestressed adjustable structure. A spiral adjustment knob or a push rod driven by a stepper motor is provided on the housing of the flexible hinge mechanism 120, which constitutes the prestress adjustment end. For intuitive user operation, the control system 300 also includes an interactive panel located on the front side of the lower plate base, which integrates a function for real-time display of doneness. An LCD display showing changing values ​​and a buzzer alarm.

[0097] When a user is preparing to cook thinner ingredients such as jianbing (Chinese crepes), the initial compression of the spring can be reduced by adjusting the end, so that the upper plate component 100 is suspended on the ingredients with almost zero pressure. This prevents the batter from being pressed too thin, resulting in uneven crispness. When cooking thick-cut steaks or leavened pancakes that are several centimeters thick, the user or the automatic control program can increase the prestress of the adjusting end. This increased prestress provides a stable downward pressure in the early stage of the food's expansion, forcing heat to be quickly transferred to the center of the food through the physical pressing interface.

[0098] The connection between the adjustment end and the nonlinear stiffness spring mechanism 110 adopts a worm gear reduction mechanism. This structure has self-locking properties, ensuring that the prestress will not shift due to the violent expansion of the food during cooking. This exposed adjustment end design greatly enhances the flexibility of the equipment, enabling a single piece of hardware to cover a wide range of cooking objects, from ultra-thin to ultra-thick media. Through precise intervention in the initial mechanical state, the pre-optimization of thermal resistance boundary conditions is achieved.

[0099] The control system 300 includes a multi-channel data acquisition module, which is connected to a temperature sensor embedded in the center of the upper plate assembly 100 and the lower plate assembly 200.

[0100] In the embodiments supporting the above, the implementation of multi-dimensional sensing is described in detail. In order to cooperate with the acoustic impedance signal and achieve more accurate thermal field guidance, the control system 300 integrates a multi-channel data acquisition module based on the ADS1115 conversion chip. This module has a high resolution of 16 bits and can accurately capture the small fluctuations of the temperature signal.

[0101] At the geometric center of the upper plate assembly 100 and the lower plate assembly 200, WRNK-191 type K thermocouples are embedded as temperature sensors. The probes of these sensors are protected by ceramic tubes and are directly embedded deep into the aluminum alloy substrate, only 2mm away from the cooking surface. This embedded design greatly reduces the measurement delay caused by thermal inertia.

[0102] The multi-channel data acquisition module transmits these two temperature signals to the core controller of the control system 300 in real time. By comparing the temperature rise rates at the center of the upper and lower plates, the controller can correct the aforementioned asymmetric power distribution strategy in real time. For example, if the acquisition module shows that the temperature rise of the lower plate is much higher than that of the upper plate, and the ultrasonic feedback signal indicates that the bottom moisture is evaporating too quickly, the controller will automatically reduce the power duty cycle of the lower plate and increase the heat input of the upper plate. This temperature-acoustic coupled sensing mode provides comprehensive data support for the cooking process. The acquisition of multi-channel data is not only used for real-time control but also provides sample data for subsequent algorithm iterations, ensuring that every heat distribution is traceable and improving the overall intelligence level of the system.

[0103] The ring-shaped guided ultrasonic array 210 forms a uniformly distributed standing wave field on the cooking surface of the lower plate assembly 200, and the amplitude of the standing wave field is sufficient to overcome the adhesion between the food and the plate surface.

[0104] In the embodiments supporting the above, the contribution of the standing wave physical field to the taste and cleanliness of cooking is described in detail. The ring-shaped waveguide ultrasonic array 210 is designed with acoustic topology optimization. Specifically, it uses equally spaced ring-shaped reinforcing ribs on the back of the lower plate assembly 200 to reflect and interfere with sound waves, thus offsetting the attenuation of sound energy as the radius increases. This ensures that the uniformity deviation of the standing wave field on the cooking surface is less than 15%. The distribution position and excitation phase are precisely calibrated to excite a special bending vibration mode on the cooking plane of the lower plate assembly 200. This mode results in a grid-like distribution of standing wave field on the plate surface.

[0105] The characteristic of a standing wave field lies in the presence of fixed amplitude maxima and minima in spatial location. These high-frequency alternating amplitude points exert a continuous shear force on the bottom of the food. When cooking batter-like ingredients, the batter, upon heating and solidifying, easily chemically bonds with the aluminum alloy pan surface, causing it to stick. The micro-vibrations excited by the standing wave field, through high-frequency reciprocating mechanical motion, continuously break these bonds at the microscopic level.

[0106] Experiments have verified that when the amplitude of the standing wave field reaches 10μm to 20μm, the resulting local acceleration is hundreds of times greater than the acceleration due to gravity. Through high-frequency reciprocating motion, an instantaneous acoustic pressure membrane is formed between the food and the plate surface, achieving a quasi-suspended state. This energy density is sufficient to ensure that even with little or no oil, the food maintains a quasi-suspended state on the plate. This state not only makes heat conduction more uniform, avoiding burning caused by localized overheating, but also allows the food to easily slide off the plate after cooking, greatly reducing the difficulty of cleaning. The uniform distribution of the standing wave field ensures that the food enjoys the same ultrasonic gain effect regardless of its position on the plate, fundamentally improving the problem of food sticking and breaking in traditional electric griddles, and enhancing the visual appeal and overall quality of the cooked product.

[0107] Under the combined operation of all the above embodiments, this household smart electric griddle constructs an advanced cooking system with multi-physics coupling through nonlinear flexible adjustment of mechanical structure, electrical energy guidance of asymmetric dynamic heat field, and ultrasonic synergistic enhancement under ceramic heat insulation protection. This system is not merely a simple superposition of components, but rather solves the ambiguity in determining the doneness of ingredients, the uneven distribution of thermal resistance, and the uniformity of texture control through the organic coordination of sound, heat, electricity, and force. All the micro-electric push rods, such as the adjustment end that drives the displacement of the flexible hinge, can be selected as power support components. This functionally-oriented, layer-by-layer progressive design method ensures that every detail of the technical solution directly serves the final cooking effect, providing a detailed engineering practice path for the intelligent evolution of household kitchen appliances.

[0108] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method of using a household intelligent electric griddle, characterized in that, include: S1. An upper plate assembly (100), a lower plate assembly (200), and a flexible hinge mechanism (120) are provided. The lower plate assembly (200) has a ring-shaped waveguide ultrasonic array (210) installed on the edge of the lower plate base (230). The flexible hinge mechanism (120) connects the upper plate assembly (100) and the lower plate assembly (200). The flexible hinge mechanism (120) is provided with a nonlinear stiffness spring mechanism (110). S2. Place the food to be processed on the cooking surface of the lower plate assembly (200), and adjust the initial prestress of the nonlinear stiffness spring mechanism (110) to make the upper plate assembly (100) and the food surface form a flexible contact. S3. Start heating and execute dynamic asymmetric thermal field modulation. By independently modulating the power of the upper plate assembly (100) and the lower plate assembly (200) with high frequency duty cycle, the heat flow is directed inside the food. S4. During the heating process, ultrasonic assistance is activated. The standing wave generated by the ring-shaped guided ultrasonic array (210) is used to conduct micro-vibrations to the bottom of the food through the lower plate assembly (200) to break the vapor film effect at the bottom of the food and improve the heat conduction efficiency. S5. Perform online cooking monitoring, acquire the acoustic impedance feedback signal of the ring-shaped guided ultrasonic array (210) in real time, determine the cooking status of the food according to the abrupt change characteristics of the acoustic impedance feedback signal, and stop cooking.

2. The method of using a household intelligent electric griddle according to claim 1, characterized in that, The steps in S3 include: The control system (300) outputs a pulse width modulation signal with a preset carrier frequency, and independently adjusts the heat power distribution ratio between the upper and lower plates according to the type of food.

3. The method of using a household intelligent electric griddle according to claim 1, characterized in that, The steps in S4 include: The annular waveguide ultrasonic array (210) is mounted on the cold end of the lower plate assembly (200) using a ceramic heat insulation layer (220). The ultrasonic excitation frequency generated by the annular waveguide ultrasonic array (210) causes the cooking surface of the lower plate assembly (200) to produce a micron-level amplitude.

4. The method of using a household intelligent electric griddle according to claim 1, characterized in that, The steps in S5 include: The current feedback curve of the ring-shaped guided ultrasonic array (210) is monitored. When the acoustic impedance feedback signal reaches the preset phase transition threshold, it is determined that the protein denaturation or starch gelatinization of the food has been completed, and a cooking completion signal is output.

5. The method of using a household intelligent electric griddle according to claim 1, characterized in that, In step S2: The flexible hinge mechanism (120) passively adjusts the pressing force of the upper plate assembly (100) on the food through the nonlinear stiffness spring mechanism (110) according to the expansion displacement of the food during the heating process, thereby forming a steam venting micro-gap while maintaining thermal contact.

6. A household intelligent electric griddle, used to implement the method of using the household intelligent electric griddle as described in any one of claims 1 to 5, characterized in that, include: The upper plate assembly (100) and the lower plate assembly (200) are each equipped with independent heating elements; A flexible hinge mechanism (120) is connected between the upper plate assembly (100) and the lower plate assembly (200), and a nonlinear stiffness spring mechanism (110) with nonlinear stiffness characteristics is integrated inside it. The ultrasonic generating assembly includes an annular waveguide ultrasonic array (210) mounted on the edge of the lower plate assembly (200) and a ceramic heat insulation layer (220) disposed between the annular waveguide ultrasonic array (210) and the lower plate substrate. The control system (300) is electrically connected to the heating element and the ring-shaped waveguide ultrasonic array (210) respectively, and is used to realize power modulation and acoustic impedance signal acquisition.

7. A household intelligent electric griddle according to claim 6, characterized in that, The material of the lower plate assembly (200) is aluminum alloy waveguide medium, and the ring waveguide ultrasonic array (210) is installed on the cold end of the base of the lower plate assembly (200) through the ceramic heat insulation layer (220).

8. A household intelligent electric griddle according to claim 6, characterized in that, The prestress adjustment end of the nonlinear stiffness spring mechanism (110) is exposed outside the flexible hinge mechanism (120) for manually or automatically matching the initial thickness of different types of ingredients.

9. A household intelligent electric griddle according to claim 6, characterized in that, The control system (300) includes a multi-channel data acquisition module, which is connected to a temperature sensor embedded in the center of the upper plate assembly (100) and the lower plate assembly (200).

10. A household intelligent electric griddle according to claim 6, characterized in that, The ring-shaped guided ultrasonic array (210) forms a uniformly distributed standing wave field on the cooking surface of the lower plate assembly (200), and the amplitude of the standing wave field is sufficient to overcome the adhesion between the food and the plate surface.

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