Milk foam generation control method of stirrer

Abstract

The invention discloses a milk foam generation control method of a stirrer, a milk foam generation process comprises an initial stirring stage, a main foaming stirring stage and a stabilization stage, the control method comprises the following steps: in the initial stirring stage, stirring blades are controlled to carry out low-speed stirring at a preset low-speed stirring rotation speed for preset low-speed stirring time; in the main foaming stirring stage, stirring blades are controlled to perform high-speed foaming at a preset basic stirring rotating speed for preset basic stirring time; in the stable stage, the stirring blades are controlled to stir at a preset refining stirring speed for a preset basic refining stirring time so as to refine the generated milk foam; wherein the preset basic stirring rotating speed is greater than the preset refining stirring rotating speed, and the preset refining stirring rotating speed is greater than the preset low-speed stirring rotating speed. According to the invention, the consistency of milk foam products of the stirrer in different environments can be ensured, so that standardized quality control of cross-regional stores is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of blender program control, and in particular to a method for controlling milk foam generation of a blender. Background Art

[0002] With the rapid development of the ready-made coffee and tea beverage industry, the performance of the milk frother, as one of the core equipment, directly determines the quality and taste of the beverage. As an important component of coffee and tea beverages, milk foam not only affects the visual presentation of the beverage, but also profoundly shapes the consumer's taste experience through characteristics such as fineness, stability and viscosity. In the field of coffee beverage production, the handheld blender has brought a revolutionary breakthrough in milk foam production with its lightweight, easy-to-carry, and compact design advantages. Its compact shape is easy to hold and store, suitable for high-frequency operations in stores, and can easily cope with temporary outdoor production scenarios, greatly improving the flexibility of milk foam production.

[0003] However, current handheld blenders on the market rely on standardized control parameters (such as fixed speed and blending time) during the milk froth production process, making them unable to adapt to the complex environmental differences found in stores across China. Different regions inevitably introduce new factors that affect the fineness, stability, and viscosity of milk froth, such as varying altitudes and the temperature difference between room temperature and milk in different stores. Even with the same equipment using the same control parameters, significant differences in milk froth quality can still occur in these complex environments. This makes it impossible to ensure consistent milk froth production across different environments, making standardized quality control difficult across stores across regions. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a method and system for controlling milk foam generation in a blender, which can ensure the consistency of milk foam produced by the blender in different environments.

[0005] The technical solution of the present invention is achieved as follows:

[0006] In one aspect, the present invention provides a method for controlling milk foam generation of a blender. The milk foam generation process includes an initial stirring stage, a main foaming stirring stage, and a stabilization stage. The control method includes the following steps:

[0007] In the initial stirring stage, the stirring blade is controlled to perform low-speed stirring at a preset low-speed stirring speed for a preset low-speed stirring time;

[0008] During the main foaming and stirring stage, the stirring blades are controlled to perform high-speed foaming at a preset basic stirring speed for a preset basic stirring time;

[0009] During the stable stage, the stirring blade is controlled to stir at a preset refined stirring speed for a preset basic refined stirring time to refine the generated milk foam;

[0010] The preset basic stirring speed is greater than the preset refined stirring speed, and the preset refined stirring speed is greater than the preset low-speed stirring speed.

[0011] Preferably, the preset low-speed stirring speed includes a first preset low-speed stirring speed and a second preset low-speed stirring speed, and the preset low-speed stirring time includes a first preset low-speed stirring time and a second preset low-speed stirring time;

[0012] In the initial stirring stage, the stirring blade is first controlled to rotate at a first preset low-speed stirring speed for a first preset low-speed stirring time, and then the stirring blade is controlled to rotate at a second preset low-speed stirring speed for a second preset low-speed stirring time.

[0013] Preferably, the first preset low-speed stirring speed range is 2000-3000 rpm, the second preset low-speed stirring speed range is 3000-4000 rpm, the preset basic stirring speed range is 7000-8000 rpm, and the preset refined stirring speed range is 2000-5000 rpm.

[0014] Preferably, the mixer is provided with a first temperature sensor for detecting the ambient temperature in real time and a second temperature sensor for detecting the temperature of the foaming liquid in real time;

[0015] In the initial stirring stage, the initial temperature difference is determined based on the initial ambient temperature and the initial foaming liquid temperature, and then it is determined whether the initial temperature difference is greater than the preset temperature difference threshold. If so, the stirring blade is controlled to enter the initial stirring stage for low-speed stirring; if not, the stirring blade is controlled to enter the main foaming stirring stage.

[0016] Preferably, in the initial stirring stage, the stirring blade is controlled to rotate at a preset low stirring speed, and the real-time temperature difference is calculated in real time according to the detected ambient temperature and the temperature of the foaming liquid. When any of the following conditions is met, the stirring blade is controlled to perform high-speed foaming:

[0017] When the real-time temperature difference is less than or equal to the preset temperature difference threshold;

[0018] When the real-time temperature difference value is greater than the preset temperature difference threshold, but the low-speed stirring duration is greater than or equal to the preset low-speed stirring time.

[0019] Preferably, in the main foaming and stirring stage, the compensation coefficient is calculated based on the detected altitude parameter or the acquired altitude parameter, and the real-time temperature difference is determined based on the real-time detected ambient temperature and the foaming liquid temperature; then the stirring speed is dynamically adjusted based on the compensation coefficient, the real-time temperature difference and the preset basic stirring time, the stirring time is determined based on the compensation coefficient, and the stirring blade is controlled to perform high-speed foaming with the determined stirring time and the adjusted stirring speed.

[0020] Preferably, the step of dynamically adjusting the stirring speed based on the compensation coefficient and the real-time temperature difference value includes:

[0021] Determine in real time whether the temperature difference is greater than a preset temperature difference threshold;

[0022] If yes, then the stirring speed N is determined by the following formula: N = N base K1 (1 + α ΔT), where N base is the preset basic stirring speed, K1 is the compensation coefficient, α is the temperature difference compensation coefficient, and ΔT is the temperature difference value;

[0023] If not, the stirring speed N is determined by the following formula: N = N base ·K1.

[0024] Preferably, the specific steps of determining the stirring time according to the compensation coefficient include:

[0025] The stirring compensation time Δt is determined according to the compensation coefficient K1, specifically by the following formula: Δt = 2(K1-1), where P sea_level is the standard sea level pressure value, P current is the ambient air pressure at that time.

[0026] According to the preset basic stirring time t base The final stirring time t is determined by the stirring compensation time Δt, which is specifically determined by the following formula: t = t base +Δt.

[0027] Preferably, the mixer is further provided with an optical viscometer for detecting the viscosity of the foaming liquid, and the stirring speed of the stirring blade in the main foaming and stirring stage is adjusted in real time according to the viscosity of the foaming liquid detected by the optical viscometer;

[0028] The specific steps of adjusting the stirring speed of the stirring blade in the main foaming and stirring stage according to the viscosity of the foaming liquid detected by the optical viscometer include:

[0029] Determine the target viscosity value η based on the temperature difference ΔT and the compensation coefficient K1 target , specifically determined by the following formula: target =η base (1 + 0.005 ΔT) (1 + 0.03 (1-K1), where η base is the preset basic target viscosity value;

[0030] Using PID closed-loop control algorithm, the real-time viscosity value η current and target viscosity value η target The deviation is used as input and the stirring speed compensation value ΔN is calculated according to the following formula:

[0031]

[0032] e(t)=η target -η current ; where K p ,K i ,K d Calibrate parameters for the experiment;

[0033] The stirring speed of high-speed foaming is corrected in real time according to the calculated stirring speed compensation value ΔN.

[0034] Preferably, the mixer is further provided with an optical sensor for detecting the distribution of bubble diameters, and the stirring time in the stable stage is adjusted according to the bubble diameter distribution ratio fed back by the optical sensor;

[0035] The specific steps of adjusting the stirring time in the stabilization phase according to the bubble diameter distribution ratio fed back by the optical sensor in the stabilization phase include:

[0036] During the stabilization phase, the stirring blade is controlled to rotate alternately at high and low speeds or in forward and reverse directions for a preset basic refined stirring time. During this process, the proportion of bubbles in the milk foam with a diameter greater than a preset diameter threshold is continuously detected to see if it is greater than a preset proportion threshold. If so, the stirring time is extended by a preset unit time; otherwise, the stabilization phase ends;

[0037] After the stirring blade stirs for the preset basic refined stirring time, when it is detected that the proportion of bubbles in the milk foam with a diameter greater than the preset diameter threshold is still greater than the preset proportion threshold, the stirring time is extended by at most twice the preset unit time and then ends.

[0038] Compared with the prior art, the present invention has the following advantages: the present invention controls the milk foam generation process in three stages, namely the initial stirring stage, the main foaming stirring stage and the stabilization stage, wherein the stirring blades in different stages rotate at different speeds, and the preset basic stirring speed is greater than the preset refined stirring speed, and the preset refined stirring speed is greater than the preset low-speed stirring speed; after using the initial stirring stage to balance the temperature difference between room temperature and the foaming liquid, the main foaming stirring stage is used for high-speed foaming, and finally the stabilization stage is used to balance the diameter of the generated milk foam, so as to improve the fineness of the milk foam and ensure the stability of the milk foam structure, thereby ensuring that the blender can prepare consistent milk foam in different environments and realize standardized quality control across regional stores. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 The figure is a flow chart of the milk foam generation control method of the blender of the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] See also Figure 1 The embodiment of the present invention discloses a method for controlling milk foam generation of a blender, wherein the milk foam generation process includes an initial stirring stage, a main foaming stirring stage, and a stabilization stage. The control method includes the following steps:

[0043] S1, in the initial stirring stage, the stirring blade is controlled to stir at a preset low speed for a preset low speed stirring time;

[0044] It is understandable that the temperature difference between room temperature and the foaming liquid (such as milk) varies in different store environments in different regions. Before stirring, if the temperature difference between the milk and the environment is large, it will lead to different rates of protein denaturation, which in turn affects the milk foam structure and taste. For example, directly stirring low-temperature milk (such as refrigerated 4°C) in a high-temperature environment (such as 30°C in summer) at high speed will cause local protein denaturation (denaturation rate difference >20% when the temperature gradient is >10°C), resulting in an uneven milk foam structure. Therefore, in this application, before stirring, low-speed stirring is used to promote uniform heat distribution, thereby reducing the impact of the temperature difference between room temperature and the foaming liquid on the formation of the milk foam structure.

[0045] S2, during the main foaming and stirring stage, the stirring blades are controlled to perform high-speed foaming at a preset basic stirring speed for a preset basic stirring time;

[0046] In this embodiment, the main frothing and stirring stage is a key stage that affects the quality of milk foam. After solving the influence of the foaming liquid on the generation of milk foam under different ambient temperature differences in the initial stirring stage, high-speed frothing is performed through the main frothing and stirring stage, thereby greatly reducing the differences in milk foam products in different environments, and thus realizing standardized quality control across regional stores.

[0047] S3, in the stable stage, the stirring blade is controlled to stir at a preset refined stirring speed for a preset basic refined stirring time to refine the generated milk foam;

[0048] The preset basic stirring speed is greater than the preset refined stirring speed, and the preset refined stirring speed is greater than the preset low-speed stirring speed.

[0049] It is understandable that, since the diameters of the milk foams generated in the main frothing and stirring stage vary greatly, a stabilization stage is required to balance the diameters of the generated milk foams in order to increase the fineness of the milk foams.

[0050] In this embodiment, the milk foam generation process is divided into three stages by controlling the initial stirring stage, namely the main foaming stirring stage and the stabilization stage. The stirring blades in different stages rotate at different speeds, and the preset basic stirring speed is greater than the preset refined stirring speed, and the preset refined stirring speed is greater than the preset low-speed stirring speed. First, in the initial stirring stage, the stirring blades are controlled to balance the temperature difference between the room temperature and the foaming liquid at the lowest speed to reduce the influence of subsequent different ambient temperatures on the generation of milk foam. Then, rapid foaming is performed at the highest speed during the main foaming stirring stage. Finally, the diameter of the generated milk foam is balanced at a medium speed during the stabilization stage to increase the fineness of the milk foam and ensure the stability of the milk foam structure, thereby ensuring that the blender can prepare consistent milk foam in different environments and realize standardized quality control across regional stores.

[0051] Furthermore, the preset low-speed stirring speed includes a first preset low-speed stirring speed and a second preset low-speed stirring speed, and the preset low-speed stirring time includes a first preset low-speed stirring time and a second preset low-speed stirring time, wherein the first preset low-speed stirring speed is less than the second preset low-speed stirring speed;

[0052] In the initial stirring stage, the stirring blade is first controlled to rotate at a first preset low-speed stirring speed for a first preset low-speed stirring time, and then the stirring blade is controlled to rotate at a second preset low-speed stirring speed for a second preset low-speed stirring time.

[0053] It is understood that during the initial stirring stage, before the blender begins operation, the temperature difference between room temperature and the foaming liquid is greatest. Therefore, it is necessary to first control the stirring blades to rotate at a first, preset, low stirring speed to initially balance the temperature difference between room temperature and the foaming liquid. Then, the stirring blades are controlled to rotate at a second, higher, preset low stirring speed to quickly balance the temperature difference. This embodiment allows the temperature difference between room temperature and the foaming liquid to be balanced quickly without denaturing the protein in the foaming liquid, thereby meeting the store's needs for rapid supply.

[0054] Preferably, the first preset low-speed stirring speed range is 2000-3000 rpm, the second preset low-speed stirring speed range is 3000-4000 rpm, the preset basic stirring speed range is 7000-8000 rpm, and the preset refined stirring speed range is 2000-5000 rpm.

[0055] It can be understood that a lower stirring speed of 2000-4000 is used for pre-mixing in the initial stirring stage to quickly reduce the temperature difference; then a higher speed of 7000-8000rpm is used for high-speed foaming in the main foaming stirring stage; and after high-speed foaming, since the generated bubbles are not uniform and fine enough, it is necessary to use a lower speed of 2000-5000rpm to break up the bubbles in the stabilization stage; the finished milk foam prepared by the above parameter settings is consistent and of good quality.

[0056] In another embodiment of the present invention, further, a first temperature sensor for detecting the ambient temperature in real time and a second temperature sensor for detecting the temperature of the foaming liquid in real time are provided on the blender;

[0057] In the initial stirring stage, an initial temperature difference is determined according to the initial ambient temperature and the initial foaming liquid temperature, and the stirring blade is controlled to enter the initial stirring stage for low-speed stirring according to the determined initial temperature difference.

[0058] It is understandable that before stirring begins, if the temperature difference between the milk and the surrounding environment is large, it will lead to different rates of protein denaturation, which in turn affects the milk foam structure and taste. For example, directly stirring low-temperature milk (such as refrigerated 4°C) in a high-temperature environment (such as 30°C in summer) at high speed will cause local protein denaturation (denaturation rate difference >20% for a temperature gradient >10°C), resulting in an uneven milk foam structure. Therefore, before stirring begins, when the initial ambient temperature and the initial foaming liquid temperature differ significantly, it is necessary to control the stirring blade to stir at a low speed (typically 2000-3000 rpm) to promote even heat distribution through gentle liquid flow, avoid the impact of sudden temperature changes on milk components, and facilitate uniform distribution of the foaming liquid (such as milk) to avoid local overheating or unevenness during subsequent high-speed stirring. When the initial ambient temperature and the initial foaming liquid temperature differ closely, the impact on high-speed milk foam generation is minimal. Therefore, the stirring blade can be directly controlled to enter the main foaming stirring stage for high-speed foaming to meet the needs of stores for fast supply. Moreover, the initial viscosity of low-temperature milk is too high, and low-speed stirring can gradually reduce the viscosity to 120-130 mPa·s to match the shear force requirements of subsequent high-speed foaming.

[0059] Specifically, in the initial stirring stage, the step of determining whether to control the stirring blade to perform low-speed stirring according to the determined initial temperature difference value includes:

[0060] S101, determining whether the initial temperature difference value is greater than a preset temperature difference threshold;

[0061] S102: If yes, control the stirring blade to stir at a low speed;

[0062] S103: No, then control the stirring blade to perform high-speed foaming.

[0063] In this embodiment, for example, the preset temperature difference threshold can be set to 5°C. When the initial temperature difference value is below 5°C, the impact on high-speed foaming is already very small, and the temperature difference at this time can be adjusted using the stirring speed in the main foaming and stirring stage, so the stirring blade can be controlled to directly enter the main foaming and stirring stage; and if the initial temperature difference value is greater than 5°C, the stirring blade is controlled to perform low-speed stirring at a preset low-speed stirring speed (such as 2000-3000rpm, that is, the first preset low-speed stirring speed) to quickly balance the temperature.

[0064] More specifically, in step S102, in the initial stirring stage, the stirring blade is controlled to rotate at a preset low stirring speed, and a real-time temperature difference is calculated in real time based on the detected ambient temperature and the temperature of the foaming liquid. When any of the following conditions is met, the stirring blade is controlled to perform high-speed foaming:

[0065] When the real-time temperature difference is less than or equal to the preset temperature difference threshold (such as 5°C);

[0066] When the real-time temperature difference value is greater than the preset temperature difference threshold, but the low-speed stirring duration is greater than or equal to the preset low-speed stirring time (such as 10s).

[0067] It is understood that when the temperature difference detected is less than or equal to the preset temperature difference threshold, the low-speed stirring phase is immediately terminated and the main frothing stirring phase is entered, accelerating the blender's milk froth preparation time. To prevent the low-speed stirring phase from looping endlessly due to a malfunction of the first and second temperature sensors, when the real-time temperature difference detected is greater than the preset temperature difference threshold, but the low-speed stirring duration is greater than or equal to the preset low-speed stirring time, the stirring blades are automatically controlled to enter the main frothing stirring phase to prevent the low-speed stirring phase from being extended indefinitely. Furthermore, if the low-speed stirring time is too long, the foaming liquid may experience excessive temperature increase or decrease (for example, prolonged stirring of refrigerated milk in a high-temperature environment may cause the temperature to exceed 15°C, causing fat oxidation or excessive protein denaturation), thus destabilizing the milk froth structure. Furthermore, if the temperature difference between the foaming liquid and the ambient temperature is indeed too large, indefinitely extending the low-speed stirring time is ineffective and may even extend the milk froth preparation time, causing consumers to wait an extended time for their drinks and experiencing a poor experience. In this case, transitioning to the main frothing stirring phase and adjusting the stirring speed would actually accelerate the milk froth preparation time.

[0068] In this embodiment, in addition to the influence of the temperature difference between the room temperature and the milk in different stores on the generated milk foam, the altitude of different regions also affects the generated milk foam. Therefore, during the main frothing and stirring stage, the blender is required to be able to automatically adjust the stirring parameters in the main frothing and stirring stage in different environments, so as to more accurately ensure the consistency of milk foam products in different environments and realize standardized quality control across regional stores.

[0069] Therefore, further, in the main foaming and stirring stage in step S2, it is necessary to calculate the compensation coefficient based on the detected altitude parameter or the acquired altitude parameter, and determine the real-time temperature difference value based on the real-time detected ambient temperature and the foaming liquid temperature; then, the stirring speed is dynamically adjusted based on the compensation coefficient, the real-time temperature difference value and the preset basic stirring time, the stirring time is determined based on the compensation coefficient, and the stirring blade is controlled to perform high-speed foaming with the determined stirring time and the adjusted stirring speed.

[0070] It can be understood that the main frothing and stirring stage is a key stage that affects the quality of milk foam. Therefore, in this embodiment, the stirring speed and stirring time in the main frothing and stirring stage are dynamically adjusted according to the compensation coefficient and the real-time temperature difference value, so as to ensure consistent milk foam production in different environments and realize standardized quality control across regional stores.

[0071] Among them, an air pressure sensor for detecting altitude parameters can be set on the blender, or it can be queried through the Internet, and the present invention is not limited here.

[0072] Specifically, in step S2, the step of dynamically adjusting the stirring speed based on the compensation coefficient and the real-time temperature difference value includes:

[0073] S201, determining in real time whether the temperature difference is greater than a preset temperature difference threshold (e.g., 5°C);

[0074] S202: Yes, then the stirring speed N is determined by the following formula: N = N base K1 (1 + α ΔT), where N base is the preset basic stirring speed, K1 is the compensation coefficient, α is the temperature difference compensation coefficient (such as 0.05), and ΔT is the temperature difference value;

[0075] S203: No, then the stirring speed N is determined by the following formula: N = N base ·K1.

[0076] In this embodiment, in the main foaming and stirring stage, when the temperature difference is greater than the preset temperature difference threshold, it proves that the temperature balance in the low-speed stirring stage has not yet reached the requirement, so it is necessary to calculate the temperature by the formula N=N baseK1·(1+α·ΔT) is used to adjust the stirring speed to avoid the impact of large temperature differences on the milk foam production and the milk foam preparation time. When the temperature difference is less than the preset temperature difference threshold, the temperature difference has little effect on the milk foam production. Therefore, the calculation formula N=N base K1 can be used to adjust the stirring speed to ensure the quality of milk foam. It is understandable that the temperature compensation coefficient α can be determined by experimentally testing the quality of milk foam under different temperature differences.

[0077] In addition, in the present application, the above steps S1 and S2 are used for step-by-step control, which also simplifies the algorithm calculation control; when the temperature difference value is still greater than the preset temperature difference threshold after step S1, step S202 will be used to calculate and adjust the stirring speed N, and redundant operations are reduced through intelligent judgment, thereby improving the efficiency of commercial equipment while ensuring the quality of milk foam.

[0078] In addition, in step S2, the specific steps of determining the stirring time according to the compensation coefficient include:

[0079] The stirring compensation time Δt is determined according to the compensation coefficient K1, specifically by the following formula: Δt = 2(K1-1), where P sea_level is the standard sea level pressure value (i.e. the international standard atmospheric pressure is 101.3kPa), P current is the ambient air pressure at that time.

[0080] According to the preset basic stirring time t base The final stirring time t is determined by the stirring compensation time Δt, which is specifically determined by the following formula: t = t base +Δt.

[0081] In this embodiment, in order to ensure that the high-speed foaming time is too long, resulting in excessive shearing of the casein network in the foaming liquid, which leads to excessive viscosity drop and a significant increase in the probability of milk foam stratification, the stirring compensation time in this embodiment is determined only by the compensation coefficient K1 without the need for temperature difference. Moreover, since the core goal of the main foaming and stirring stage is to inject sufficient air and form a stable bubble structure, its time compensation is mainly aimed at the change in air density (determined by altitude) rather than heat exchange efficiency. Therefore, the stirring compensation time Δt does not involve the real-time temperature difference. In this embodiment, the stirring time is only determined by the compensation coefficient K1 and the preset basic stirring time t base The calculation is done without involving the real-time temperature difference, which can also avoid increasing the preparation time of a single cup of coffee and causing significant efficiency loss in commercial scenarios.

[0082] Furthermore, the blender is equipped with an optical viscometer for detecting the viscosity of the foaming liquid. The speed of the stirring blades during the main foaming and stirring phase is adjusted in real time based on the viscosity of the foaming liquid detected by the optical viscometer. The optical viscometer analyzes the rheological properties of the foaming liquid using near-infrared spectroscopy and outputs a real-time viscosity value. In this embodiment, considering that the viscosity of the foaming liquid directly reflects the real-time state of the milk froth, the stirring speed is adjusted in real time based on the viscosity feedback from the optical viscometer, further ensuring the quality of the milk froth.

[0083] The specific steps of adjusting the stirring speed of the stirring blade in the main foaming and stirring stage according to the viscosity of the foaming liquid detected by the optical viscometer include:

[0084] Determine the target viscosity value η based on the temperature difference ΔT and the compensation coefficient K1 target , specifically determined by the following formula: target =η base (1 + 0.005 ΔT) (1 + 0.03 (1-K1), where η base is the preset basic target viscosity value;

[0085] Using PID closed-loop control algorithm, the real-time viscosity value η current and target viscosity value η target The deviation is used as input and the stirring speed compensation value ΔN is calculated according to the following formula:

[0086]

[0087] e(t)=η target -η current ;

[0088] where K p ,K i ,K d It is the experimental calibration parameter, which can be obtained through step response test optimization, such as K p ,K i ,K d Possible values are: K p =0.8, K i =0.2,K d =0.1;

[0089] According to the calculated stirring speed compensation value ΔN, the stirring speed of high-speed foaming is corrected in real time, that is, the final stirring speed is N 最终 =N+ΔN.

[0090] In the embodiment of the present invention, since the initial viscosity of different foaming liquids is different (for example, the initial viscosity of whole milk is higher and the initial viscosity of skim milk is lower), and the viscosity of the foaming liquid decreases with increasing temperature, and the viscosity decreases in different foaming liquids has different laws, for example, the viscosity of milk decreases by about 15% for every 10°C increase in temperature, the target viscosity needs to be dynamically adjusted according to the temperature difference and the compensation coefficient, and then the real-time viscosity value η is adjusted using the PID closed-loop control algorithm. current and target viscosity value η target The deviation is used as input to calculate the stirring speed compensation value ΔN to ensure the quality of milk foam.

[0091] In step S3, further, after the high-speed foaming stirring time, the stirring blade is controlled to rotate alternately at high and low speeds or forward and reverse directions to refine the generated milk foam.

[0092] It's understood that when the diameters of milk bubbles after high-speed frothing vary significantly, the resulting milk bubbles can be refined by alternating high and low speeds, or by alternating forward and reverse rotation, to improve the fineness of the froth. For example, the stirring blades can be controlled in a pulsed mode. For example, a high pulse period of 5000-6000 rpm for 0.5 seconds generates strong shear force to break up large bubbles; a low pulse period of 2000-3000 rpm for 0.5 seconds allows liquid to fill the gaps between bubbles and distribute evenly, with alternating high and low speeds.

[0093] Furthermore, the blender is equipped with an optical sensor for detecting bubble diameter distribution. During the stabilization phase, the blending time is adjusted based on the bubble diameter distribution ratio reported by the optical sensor. It is understood that after the main frothing and blending phase, the generated milk foam has a larger and more uneven diameter, so it is necessary to switch the blending blade to a pulse mode (e.g., alternating 5000 rpm and 2000 rpm) to eliminate large bubbles. In this embodiment of the present invention, by using an optical sensor to detect the diameter distribution of the generated milk foam and adjust the blending time during the stabilization phase, the fineness of the milk foam can be further improved, ensuring a stable milk foam structure.

[0094] Specifically, the specific steps of adjusting the stirring time in the stabilization stage according to the bubble diameter distribution ratio fed back by the optical sensor in the stabilization stage include:

[0095] During the stabilization phase, the stirring blade is controlled to rotate alternately at high and low speeds or in forward and reverse directions for a preset basic refined stirring time. During this process, the proportion of bubbles in the milk foam with a diameter greater than a preset diameter threshold is continuously detected to see if it is greater than a preset proportion threshold. If so, the stirring time is extended by a preset unit time; otherwise, the stabilization phase ends;

[0096] After the stirring blade stirs for the preset basic refined stirring time, when it is detected that the proportion of bubbles in the milk foam with a diameter greater than the preset diameter threshold is still greater than the preset proportion threshold, the stirring time is extended by at most twice the preset unit time and then ends.

[0097] In the embodiment of the present invention, assuming that the preset diameter threshold is 0.5 mm, if the proportion of bubbles with a diameter greater than 0.5 mm in the milk foam is continuously detected to be greater than the preset proportion threshold (such as 10%) during the stable stage, the stirring time for refining the milk foam is extended by a preset unit time, that is, the stirring time for refining the milk foam = the preset basic refining stirring time + the preset unit time; after the stirring blade stirs for the preset basic refining stirring time (such as 5 seconds), when it is detected that the proportion of bubbles with a diameter greater than 0.5 mm in the milk foam is still greater than the preset proportion threshold, the preset unit time is further extended, and the extension is no more than twice at most, so as to avoid the milk foam preparation time being too long, and also to avoid excessive stirring causing excessive stretching of the protein (especially casein) fiber network in the milk, resulting in a decrease in its elasticity, and also easily causing the milk foam to stratify. For example, assuming that the preset basic refined stirring time is 5s, the preset proportion threshold is 10%, and the preset diameter threshold is 0.5mm, when the proportion of bubbles >0.5mm is detected to be 12% at the 3rd second, the preset unit time (such as 1 second) is triggered to be extended. When the proportion of bubbles >0.5mm is detected to be 11% at the 5th second, the preset unit time (such as 1 second) is further extended. When the proportion of bubbles >0.5mm is detected to be 8% at the 6th second, the detection standard is met and the refined milk foam stage is terminated, and the milk foam preparation is completed.

[0098] The embodiment of the present invention can ensure that the blender can prepare milk foam at the fastest speed under different environments and ensure the consistency of milk foam products under different environments, thereby realizing standardized quality control of stores across regions.

[0099] In summary, the present invention divides the process of controlling milk foam generation into three stages: a low-speed stirring stage, a high-speed foaming stage, and a fine milk foaming stage. Since the high-speed foaming stage is a key stage affecting the quality of milk foam, in this process, a compensation coefficient is calculated based on the detected or acquired altitude parameter, a real-time temperature difference is determined based on the real-time detected ambient temperature and the temperature of the foaming liquid, and then the stirring speed is dynamically adjusted based on the compensation coefficient and the real-time temperature difference. The stirring time is determined based on the compensation coefficient, and the stirring blade is controlled to perform high-speed foaming with the determined stirring time and the adjusted stirring speed. This ensures that the blender can automatically adjust the stirring parameters in different environments, thereby ensuring the consistency of milk foam products in different environments and achieving standardized quality control for stores across regions. In addition, the present invention also determines whether to control the stirring blade to stir at a low speed based on the initial temperature difference to ensure that the blender can produce consistent milk foam in the shortest time to meet the needs of stores for rapid supply.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling milk foam generation of a blender, characterized in that: The milk foam generation process includes an initial stirring stage, a main foaming stirring stage, and a stabilization stage. The control method includes the following steps: In the initial stirring stage, the stirring blade is controlled to perform low-speed stirring at a preset low-speed stirring speed for a preset low-speed stirring time; During the main foaming and stirring stage, the stirring blades are controlled to perform high-speed foaming at a preset basic stirring speed for a preset basic stirring time; During the stable stage, the stirring blade is controlled to stir at a preset refined stirring speed for a preset basic refined stirring time to refine the generated milk foam; The preset basic stirring speed is greater than the preset refined stirring speed, and the preset refined stirring speed is greater than the preset low-speed stirring speed.

2. The method for controlling milk foam generation of a blender according to claim 1, characterized in that: The preset low-speed stirring speed includes a first preset low-speed stirring speed and a second preset low-speed stirring speed, and the preset low-speed stirring time includes a first preset low-speed stirring time and a second preset low-speed stirring time, wherein the first preset low-speed stirring speed is less than the second preset low-speed stirring speed; In the initial stirring stage, the stirring blade is first controlled to rotate at a first preset low-speed stirring speed for a first preset low-speed stirring time, and then the stirring blade is controlled to rotate at a second preset low-speed stirring speed for a second preset low-speed stirring time.

3. The method for controlling milk foam generation of a blender according to claim 2, characterized in that: The first preset low-speed stirring speed range is 2000-3000 rpm, the second preset low-speed stirring speed range is 3000-4000 rpm, the preset basic stirring speed range is 7000-8000 rpm, and the preset refined stirring speed range is 2000-5000 rpm.

4. The method for controlling milk foam generation of a blender according to claim 1, wherein: The mixer is provided with a first temperature sensor for detecting the ambient temperature in real time and a second temperature sensor for detecting the temperature of the foaming liquid in real time; In the initial stirring stage, the initial temperature difference is determined based on the initial ambient temperature and the initial foaming liquid temperature, and then it is determined whether the initial temperature difference is greater than the preset temperature difference threshold. If so, the stirring blade is controlled to enter the initial stirring stage for low-speed stirring; if not, the stirring blade is controlled to enter the main foaming stirring stage.

5. The method for controlling milk foam generation of a blender according to claim 4, characterized in that: In the initial stirring stage, the stirring blade is controlled to rotate at a preset low stirring speed, and the real-time temperature difference is calculated in real time based on the detected ambient temperature and the temperature of the foaming liquid. When any of the following conditions is met, the stirring blade is controlled to perform high-speed foaming: When the real-time temperature difference is less than or equal to the preset temperature difference threshold; When the real-time temperature difference value is greater than the preset temperature difference threshold, but the low-speed stirring duration is greater than or equal to the preset low-speed stirring time.

6. The method for controlling milk foam generation of a blender according to claim 4, characterized in that: During the main foaming and stirring phase, a compensation coefficient is calculated based on the detected or acquired altitude parameters, and a real-time temperature difference is determined based on the real-time detected ambient temperature and the foaming liquid temperature; Then, the stirring speed is dynamically adjusted based on the compensation coefficient, the real-time temperature difference and the preset basic stirring time, the stirring time is determined based on the compensation coefficient, and the stirring blade is controlled to perform high-speed foaming with the determined stirring time and the adjusted stirring speed.

7. The method for controlling milk foam generation of a blender according to claim 6, characterized in that: The step of dynamically adjusting the stirring speed based on the compensation coefficient and the real-time temperature difference comprises: Determine in real time whether the temperature difference is greater than a preset temperature difference threshold; If yes, then the stirring speed N is determined by the following formula: N = N base K1 (1 + α ΔT), where N base is the preset basic stirring speed, K1 is the compensation coefficient, α is the temperature difference compensation coefficient, and ΔT is the temperature difference value; If not, the stirring speed N is determined by the following formula: N = N base ·K1.

8. The method for controlling milk foam generation of a blender according to claim 6, characterized in that: The specific steps of determining the stirring time according to the compensation coefficient include: The stirring compensation time Δt is determined according to the compensation coefficient K1, specifically by the following formula: Δt = 2(K1-1), where P sea_level is the standard sea level pressure value, P current is the ambient air pressure at that time. According to the preset basic stirring time t base The final stirring time t is determined by the stirring compensation time Δt, which is specifically determined by the following formula: t = t base +Δt.

9. The method for controlling milk foam generation of a blender according to claim 4, characterized in that: The mixer is also equipped with an optical viscometer for detecting the viscosity of the foaming liquid. The stirring speed of the stirring blade in the main foaming and stirring stage is adjusted in real time according to the viscosity of the foaming liquid detected by the optical viscometer. The specific steps of adjusting the stirring speed of the stirring blade in the main foaming and stirring stage according to the viscosity of the foaming liquid detected by the optical viscometer include: Determine the target viscosity value η based on the temperature difference ΔT and the compensation coefficient K1 target , specifically determined by the following formula: target =η base (1 + 0.005 ΔT) (1 + 0.03 (1-K1), where η base is the preset basic target viscosity value; Using PID closed-loop control algorithm, the real-time viscosity value η current and target viscosity value η target The deviation is used as input and the stirring speed compensation value ΔN is calculated according to the following formula: e(t)=η target -η current ; where K p ,K i ,K d Calibrate parameters for the experiment; The stirring speed of high-speed foaming is corrected in real time according to the calculated stirring speed compensation value ΔN.

10. The method for controlling milk foam generation of a blender according to claim 1, characterized in that: The mixer is also equipped with an optical sensor for detecting the distribution of bubble diameters. During the stabilization phase, the stirring time is adjusted according to the bubble diameter distribution ratio fed back by the optical sensor. The specific steps of adjusting the stirring time in the stabilization stage according to the bubble diameter distribution ratio fed back by the optical sensor in the stabilization stage include: During the stabilization phase, the stirring blade is controlled to rotate alternately at high and low speeds or in forward and reverse directions for a preset basic refined stirring time. During this process, the proportion of bubbles in the milk foam with a diameter greater than a preset diameter threshold is continuously detected to see if it is greater than a preset proportion threshold. If so, the stirring time is extended by a preset unit time; otherwise, the stabilization phase ends; After the stirring blade stirs for the preset basic refined stirring time, when it is detected that the proportion of bubbles in the milk foam with a diameter greater than the preset diameter threshold is still greater than the preset proportion threshold, the stirring time is extended by at most twice the preset unit time and then ends.

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