A heating and constant temperature control system for a heat therapy product

Abstract

This invention relates to a heating and temperature control system for a heat therapy product, comprising: a multi-dimensional data acquisition module for real-time acquisition of interface temperature data, heating element side temperature data, ambient temperature data, heat flux density data, and contact pressure distribution data at the interface between the heat therapy product and the human body; a dynamic thermal resistance compensation model, which dynamically calculates the estimated contact thermal resistance under the current operating conditions based on the contact pressure distribution data and heat flux density data, and generates a dynamic compensation coefficient based on the estimated contact thermal resistance; and a control unit, which is electrically connected to both the multi-dimensional data acquisition module and the dynamic thermal resistance compensation model, and is configured to: acquire a preset target temperature value; and construct a comprehensive deviation signal with time-varying characteristics based on the deviation between the interface temperature data and the target temperature value, combined with the dynamic compensation coefficient. This invention enables better heating and temperature control of the heat therapy product.

Description

Technical Field

[0001] This invention relates to the field of temperature control, and more specifically to a constant temperature control system for a heat therapy product. Background Technology

[0002] Heating products are widely used in daily physiotherapy and rehabilitation care. Heating and constant temperature control is the core technology of heating products, and its control effect directly determines the user experience and safety, making it a core direction for the technological development and performance optimization of such products. With the market's increasing demands for user experience and temperature control accuracy in heating products, coupled with the promotion and application of medical-grade heating products, the industry has raised higher technical standards for the dynamic adaptability, complex operating condition adaptability, and safety protection capabilities of heating product heating and constant temperature control systems. In actual use, heating products exhibit complex heat transfer characteristics at the interface with the human body. The contact thermal resistance dynamically changes with the contact pressure distribution and adhesion state of different parts of the body. Simultaneously, real-time fluctuations in ambient temperature and the thermal inertia of the heating element itself significantly affect the constant temperature control effect at the contact interface. Therefore, a heating and constant temperature control system for heating products is proposed. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a heating and constant temperature control system for a heat therapy product, comprising: The multi-dimensional data acquisition module is used to acquire in real time interface temperature data, heating element side temperature data, ambient temperature data, heat flux density data, and contact pressure distribution data of the interface between the heat therapy product and the human body. The dynamic thermal resistance compensation model is based on contact pressure distribution data and heat flux density data. It dynamically calculates the estimated contact thermal resistance under the current operating conditions and generates dynamic compensation coefficients based on the estimated contact thermal resistance. The control unit is electrically connected to both the multidimensional data acquisition module and the dynamic thermal resistance compensation model. The control unit is configured as follows: Obtain the preset target temperature value; Based on the deviation between the interface temperature data and the target temperature value, and combined with the dynamic compensation coefficient, a comprehensive deviation signal with time-varying characteristics is constructed. An adaptive PID calculation is performed based on the comprehensive deviation signal to generate the initial heating drive power; The initial heating drive power is corrected by a thermal inertial energy scheduling mechanism, and the final heating drive power is output to control the operation of the heating element.

[0004] Furthermore, the process of generating dynamic compensation coefficients in the dynamic thermal resistance compensation model includes: Obtain the average contact pressure value after spatial integration processing of the contact pressure distribution data; Acquire heat flux density data, interface temperature data, and temperature data on the heating element side; The estimated contact thermal resistance is obtained by performing thermal resistance inversion calculations using the difference between interface temperature data and heating element side temperature data, as well as heat flux density data, and then performing nonlinear corrections based on the average contact pressure value. The calculation formula is as follows: ; in, For interface temperature data, Here, q represents the temperature data on the heating element side, and q represents the heat flux density data. It is a nonlinear correction function based on the average contact pressure value P; The dynamic compensation coefficient is calculated based on the deviation rate between the estimated contact thermal resistance and the preset reference thermal resistance.

[0005] Furthermore, the process by which the control unit constructs the comprehensive deviation signal includes: Obtain the static deviation between the interface temperature data and the target temperature value; Ambient temperature data is acquired as a feedforward perturbation signal; The rate of change of interface temperature data over time is used as a temperature trend prediction signal. The comprehensive deviation signal is obtained by fusing the product of the static deviation and the dynamic compensation coefficient, the weighted value of the feedforward disturbance signal, and the weighted value of the temperature trend prediction signal. The calculation formula is as follows: ; in, Here, e(t) is the dynamic compensation coefficient, and e(t) is the static deviation. The target temperature value, For ambient temperature data, It serves as a compensation factor for environmental disturbances. This represents the damping factor for the rate of temperature change.

[0006] Furthermore, the adaptive PID calculation specifically includes: The proportional coefficient is dynamically adjusted based on the spatial dispersion index of the contact pressure distribution data. The spatial dispersion index is obtained by normalizing the variance of the contact pressure distribution data. When the spatial dispersion index is higher than the preset threshold, the proportional coefficient is increased to improve the system response speed. The integral coefficient is adjusted piecewise nonlinearly based on the time accumulation of the comprehensive deviation signal to suppress integral saturation. The differential coefficients are adaptively adjusted according to the fluctuation range of the temperature change rate to suppress system overshoot; The initial heating drive power is obtained by performing proportional, integral, and differential operations on the comprehensive deviation signal combined with the dynamically adjusted proportional coefficient, integral coefficient, and derivative coefficient.

[0007] Furthermore, the thermal inertial energy dispatch mechanism includes: The energy pre-scheduling unit is used to estimate the heat reserve threshold required to reach steady state based on interface temperature data, target temperature value and contact thermal resistance estimate, using a thermal balance inversion algorithm. An energy dissipation unit is used to monitor the residual heat accumulation status of the heating element; The final output heating drive power is obtained in the following way: when the difference between the initial heating drive power and the current actual output power exceeds the heat storage threshold, the thermal inertia energy scheduling mechanism intervenes, replacing the abrupt shutdown with a step-decreasing power curve, and performing virtual energy discharge compensation through the energy discharge unit to eliminate temperature overshoot.

[0008] Furthermore, the process by which the thermal inertial energy dispatch mechanism executes a step-decreasing power curve includes: Obtain the preset thermal inertia time constant of the heating element; Calculate the power decrease step size based on the thermal inertia time constant and the current rate of change of the interface temperature data; The stepped decreasing power curve is generated by gradually reducing the initial heating drive power to zero power in progressively decreasing steps, where the duration of each step is monotonically positively correlated with the estimated contact thermal resistance.

[0009] Furthermore, the interface temperature data is multi-point distributed temperature data; the control system also includes a contact state adaptive compensation module, which identifies local detached areas based on the contact pressure distribution data. When a local detached area is identified, the control unit shields the temperature acquisition signal corresponding to the local detached area in the adaptive PID calculation, and reconstructs the comprehensive deviation signal based on the pressure gradient distribution of adjacent areas to maintain a constant temperature in the contact area.

[0010] Furthermore, it also includes an independent redundant verification loop, which operates in parallel with the control unit to compare the absolute value of the deviation between the interface temperature data and the target temperature value in real time, and to monitor the fluctuation range of the dynamic compensation coefficient. When the absolute value of the deviation exceeds the first safety threshold or the dynamic compensation coefficient exceeds the second safety threshold, the independent redundant verification loop directly cuts off the power supply circuit of the heating element and simultaneously forces the integral accumulation term of the adaptive PID calculation to freeze.

[0011] The present invention has the following advantages over the prior art: The multi-dimensional data acquisition module comprehensively acquires data on the contact interface, heating element side, ambient temperature and heat flux density, and contact pressure distribution. Combined with a dynamic thermal resistance compensation model, it can accurately and dynamically calculate the estimated contact thermal resistance and generate dynamic compensation coefficients, allowing temperature control to adapt to different contact pressure conditions. The comprehensive deviation signal constructed by the control unit integrates static deviation, dynamic compensation coefficients, environmental disturbance feedforward signals, and temperature trend prediction signals, making deviation judgment more consistent with actual operating condition changes. The adaptive PID calculation dynamically adjusts the proportional coefficient according to the spatial dispersion index of the contact pressure distribution, nonlinearly adjusts the integral coefficient according to the cumulative amount of comprehensive deviation over time, and adaptively adjusts the derivative coefficient according to the fluctuation amplitude of the temperature change rate. This not only improves the system response speed but also effectively suppresses integral saturation and system overshoot, making the generation of initial heating drive power more accurate. The thermal inertia energy scheduling mechanism estimates the heat reserve threshold through a thermal balance inversion algorithm. When the power difference exceeds the threshold, it replaces abrupt changes with a step-decreasing power curve. The system shuts off and, combined with virtual energy discharge compensation, eliminates temperature overshoot, avoiding temperature deviations caused by residual heat from the heating element. The contact state adaptive compensation module identifies local detached areas, shields corresponding temperature acquisition signals, and reconstructs the regional weights of the comprehensive deviation signal based on the pressure gradient distribution of adjacent areas, ensuring a constant temperature in the area where the heat therapy product contacts the body. An independent redundant verification circuit operates in parallel with the control unit, monitoring the absolute value of the deviation between the interface temperature and the target temperature, as well as the fluctuation range of the dynamic compensation coefficient. When relevant values ​​exceed safety thresholds, it directly cuts off the power supply circuit to the heating element and freezes the integral accumulation term of the adaptive PID calculation, providing dual safety guarantees for system operation. Overall, this gives the heat therapy product's heating and temperature control strong dynamic adaptability, high control precision, and high operational safety. It can dynamically adjust the heating drive power in real time according to various actual working conditions such as contact pressure, ambient temperature, and contact state, achieving precise and stable temperature control of the human contact interface, significantly improving the user experience and safety of the heat therapy product. Attached Figure Description

[0012] Figure 1 This is a system block diagram of the present invention. Detailed Implementation

[0013] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0014] like Figure 1 As shown, a heating and constant temperature control system for a heat therapy product includes: The multi-dimensional data acquisition module is used to acquire in real time interface temperature data, heating element side temperature data, ambient temperature data, heat flux density data, and contact pressure distribution data of the interface between the heat therapy product and the human body. The dynamic thermal resistance compensation model is based on contact pressure distribution data and heat flux density data. It dynamically calculates the estimated contact thermal resistance under the current operating conditions and generates dynamic compensation coefficients based on the estimated contact thermal resistance. The control unit is electrically connected to both the multidimensional data acquisition module and the dynamic thermal resistance compensation model. The control unit is configured as follows: Obtain the preset target temperature value; Based on the deviation between the interface temperature data and the target temperature value, and combined with the dynamic compensation coefficient, a comprehensive deviation signal with time-varying characteristics is constructed. An adaptive PID calculation is performed based on the comprehensive deviation signal to generate the initial heating drive power; The initial heating drive power is corrected by a thermal inertial energy scheduling mechanism, and the final heating drive power is output to control the operation of the heating element.

[0015] The process of generating dynamic compensation coefficients in a dynamic thermal resistance compensation model includes: Obtain the average contact pressure value after spatial integration processing of the contact pressure distribution data; Acquire heat flux density data, interface temperature data, and temperature data on the heating element side; The estimated contact thermal resistance is obtained by performing thermal resistance inversion calculations using the difference between the interface temperature data and the temperature data on the heating element side, as well as the heat flux density data, and then performing nonlinear corrections based on the average contact pressure value. The calculation formula is as follows: ; in, For interface temperature data, Here, q represents the temperature data on the heating element side, and q represents the heat flux density data. It is a nonlinear correction function based on the average contact pressure value P; The dynamic compensation coefficient is calculated based on the deviation rate between the estimated contact thermal resistance and the preset reference thermal resistance. By spatially integrating the contact pressure distribution data to obtain the average contact pressure value, and combining it with interface temperature, heating element side temperature, and heat flux density data, a contact thermal resistance estimate is obtained through thermal resistance inversion calculation and superimposed with a nonlinear correction based on the average contact pressure. Then, a dynamic compensation coefficient is generated based on the deviation rate between this estimate and the preset benchmark thermal resistance value. This accurately quantifies the contact thermal resistance under different contact pressure conditions, making up for the inherent bias of traditional thermal resistance calculations that do not consider the influence of contact pressure. The generation of the dynamic compensation coefficient is made to perfectly match the actual contact conditions between the heat therapy product and the human body, providing an accurate and realistic compensation basis for the subsequent control unit to construct a comprehensive deviation signal. This improves the scientificity and accuracy of contact thermal resistance calculation from the basic data level, avoids deviations in the dynamic compensation coefficient caused by inaccurate contact thermal resistance estimation, and thus prevents problems such as improper compensation and insufficient temperature control accuracy in subsequent temperature control.

[0016] Set up the actual working conditions of the heat therapy product in contact with the human shoulder, and preset the reference contact thermal resistance value of the product. The nonlinear correction function is selected in the form of a power function that closely matches the actual contact characteristics. (P represents the average contact pressure, unit: MPa). The average contact pressure value is obtained after real-time acquisition and spatial integration by the multi-dimensional data acquisition module. At the same time, the interface temperature was collected. Temperature on the heating element side Heat flux density data .

[0017] Based on the formula for estimating contact thermal resistance, first calculate the ratio of temperature difference to heat flux density: Then calculate the value of the nonlinear correction function: ; Substitute the above results into the formula to calculate the estimated contact thermal resistance: The negative sign indicates that heat flow is transferred from the heating element side to the human body interface side, which conforms to the actual heat transfer direction. The absolute value is taken as the reference value for the actual contact thermal resistance. ; Calculate the deviation rate between the estimated contact thermal resistance and the preset reference thermal resistance value. The formula for calculating the deviation rate is as follows: Substituting the data, we get: ; The dynamic compensation coefficient is set to be linearly related to the deviation rate, and the correlation formula is as follows: Substitute the deviation rate data to calculate the dynamic compensation coefficient: .

[0018] This dynamic compensation coefficient will serve as the core parameter for the subsequent control unit to construct the comprehensive deviation signal, accurately compensating for the temperature control deviation caused by the large contact thermal resistance due to the small contact pressure. This will allow the subsequent temperature adjustment to better match the current actual contact conditions and avoid the problem of inaccurate interface temperature control caused by using a fixed compensation coefficient without considering the pressure effect.

[0019] The process by which the control unit constructs the comprehensive deviation signal includes: Obtain the static deviation between the interface temperature data and the target temperature value; Ambient temperature data is acquired as a feedforward perturbation signal; The rate of change of interface temperature data over time is used as a temperature trend prediction signal. The comprehensive deviation signal is obtained by fusing the product of the static deviation and the dynamic compensation coefficient, the weighted value of the feedforward disturbance signal, and the weighted value of the temperature trend prediction signal. The calculation formula is as follows: ; in, Here, e(t) is the dynamic compensation coefficient, and e(t) is the static deviation. The target temperature value, For ambient temperature data, It serves as a compensation factor for environmental disturbances. The damping factor is the rate of temperature change. By fusing the product of static deviation and dynamic compensation coefficient, the weighted feedforward signal of ambient temperature disturbance, and the weighted trend prediction signal of interface temperature change rate to construct a comprehensive deviation signal, the limitations of traditional control relying solely on static temperature deviation are overcome. This approach comprehensively considers the dynamic compensation requirements caused by contact thermal resistance, the external disturbance impact of ambient temperature changes, and the real-time trend of interface temperature changes. The resulting comprehensive deviation signal possesses time-varying characteristics and accurately reflects the actual temperature deviation state under multiple coupled operating conditions. It can compensate for environmental disturbances in advance and predict temperature change trends, effectively avoiding control lag, incomplete compensation, or misjudgment problems caused by a single static deviation signal. This provides a more accurate deviation input basis for subsequent adaptive PID calculations, improving the accuracy, response timeliness, and adaptability of temperature control from the signal source level.

[0020] Continuing with the actual working conditions of the heat therapy product in contact with the human shoulder, the calculated dynamic compensation coefficient is used. Preset target temperature for heat therapy products The interface temperature was collected in real time by the multi-dimensional data acquisition module. Ambient temperature With the environmental disturbance compensation factor α=0.05 and the temperature change rate damping factor β=2 set, the rate of change of interface temperature over time was calculated through real-time monitoring. .

[0021] Calculate the static deviation between the interface temperature and the target temperature. The calculation formula is: Substituting the data yields ; Calculate the product term of the dynamic compensation coefficient and the static deviation, i.e. ; The weighted feedforward term for the environmental disturbance is calculated using the following formula: Substituting the data, we get: 0.05×(42-25)=0.05×17=0.85℃; The weighted signal term for temperature trend prediction is calculated using the following formula: Substituting the data, we get: 2 × 0.3 = 0.6℃; Based on the formula for calculating the comprehensive deviation signal, substituting the above calculation results, we obtain the comprehensive deviation signal: .

[0022] This comprehensive deviation signal is not a single static deviation of -1℃, but rather a result that integrates dynamic compensation for contact thermal resistance, feedforward of ambient temperature disturbance, and prediction of temperature change trends. It accurately reflects the actual working conditions where the current contact thermal resistance is too high, the ambient temperature is lower than the target temperature, and the interface temperature is gradually rising. Inputting this time-varying comprehensive deviation signal into the subsequent adaptive PID calculation allows the heating drive power generated by the PID calculation to be more adapted to the current actual working conditions, avoiding the problem of excessively high or low heating power output caused by relying solely on static deviation control, and ensuring the accuracy and timeliness of temperature regulation.

[0023] Adaptive PID calculation specifically includes: The proportional coefficient is dynamically adjusted based on the spatial dispersion index of the contact pressure distribution data. The spatial dispersion index is obtained by normalizing the variance of the contact pressure distribution data. When the spatial dispersion index is higher than the preset threshold, the proportional coefficient is increased to improve the system response speed. The integral coefficient is adjusted piecewise nonlinearly based on the time accumulation of the comprehensive deviation signal to suppress integral saturation. The differential coefficients are adaptively adjusted according to the fluctuation range of the temperature change rate to suppress system overshoot; The initial heating drive power is obtained by performing proportional, integral, and differential operations on the comprehensive deviation signal combined with the dynamically adjusted proportional coefficient, integral coefficient, and derivative coefficient. Adaptive PID calculation dynamically adjusts the proportional coefficient based on the spatial dispersion index of the contact pressure distribution data, enabling the system to improve its response speed in cases of uneven contact pressure distribution. It also adjusts the integral coefficient nonlinearly based on the time accumulation of the comprehensive deviation signal, effectively suppressing integral saturation and preventing system control misalignment. Furthermore, it adaptively adjusts the derivative coefficient based on the fluctuation amplitude of the temperature change rate, precisely suppressing system overshoot. Compared to traditional fixed-parameter PID calculation, this adaptive method allows the PID parameters to fully adapt to the dynamic operating conditions of the heat therapy product, solving the shortcomings of traditional PID such as slow response, large overshoot, and integral saturation under different contact states and temperature change trends. This makes the initial heating drive power generated based on the comprehensive deviation signal more accurate and closely matches actual control requirements, significantly improving the dynamic response capability and control stability of the system's temperature control. It also provides a precise initial basis for subsequent power correction by the thermal inertia energy scheduling mechanism.

[0024] Continuing with the actual working conditions of the aforementioned heat therapy product in contact with the human shoulder, the calculated comprehensive deviation signal is used. Interfacial temperature change rate The spatial dispersion index of the contact pressure distribution data after variance normalization is preset to 0.4 (the preset threshold for this index is 0.3, and the index is higher than the threshold). The segmented intervals of the cumulative time value of the comprehensive deviation signal are set as follows: The integral coefficient is taken as the base value. The integral factor is set to 0.6 times the base value, and the temperature change rate fluctuation threshold is set to 0.1℃ / s. The temperature change rate fluctuation under this operating condition is... (Above the threshold), and preset the PID basic parameters: basic proportional coefficient. When the spatial dispersion index is higher than the threshold, the proportional coefficient adjustment factor k=1.8, and the basic integral coefficient. Fundamental differential coefficients When the temperature change rate fluctuation exceeds the threshold, the differential coefficient adjustment factor m = 1.7, taking the time window. The time accumulation of the comprehensive deviation signal is calculated. The rate of change of the comprehensive deviation signal was also calculated. .

[0025] Calculate the dynamically adjusted proportional coefficient The calculation formula is: Substituting the data, we get: ; Based on the segmentation rules of the cumulative time value of the comprehensive deviation signal, because Set the integral coefficient for this interval to 0.4 times the base value, and calculate the dynamically adjusted integral coefficient. The calculation formula is: Substituting the data, we get: ; Calculate the dynamically adjusted differential coefficients The calculation formula is: Substituting the data, we get: ; The initial heating drive power is calculated using a position-based adaptive PID calculation formula. The formula is First, calculate the value of each item separately: ; ; ; Substituting the results of each item into the formula, the initial heating drive power is calculated: A negative power value indicates that the heating power needs to be increased to compensate for the temperature deviation. The absolute value is taken as the reference value for the actual initial heating drive power. .

[0026] The initial heating drive power is calculated based on dynamically adjusted PID parameters, adapting to the actual working conditions of high contact pressure distribution dispersion and large temperature change rate fluctuations. Compared to using fixed parameters, this method is more efficient. The calculated initial heating drive power is 2×(-1.464)+1.0×(-7.32)+0.3×0.2=-10.188W, which effectively avoids the problem of overshoot caused by excessive heating power output due to fixed parameters. At the same time, due to the increase of the proportional coefficient, the system can quickly respond to the current temperature deviation. The segmented adjustment of the integral coefficient also avoids the integral saturation phenomenon caused by excessive integral accumulation, making the output of the initial heating drive power more accurate and adaptable to the actual control requirements.

[0027] Thermal inertial energy dispatch mechanisms include: The energy pre-scheduling unit is used to estimate the heat reserve threshold required to reach steady state based on interface temperature data, target temperature value and contact thermal resistance estimate, using a thermal balance inversion algorithm. An energy dissipation unit is used to monitor the residual heat accumulation status of the heating element; The final output heating drive power is obtained in the following way: when the difference between the initial heating drive power and the current actual output power exceeds the heat storage threshold, the thermal inertia energy scheduling mechanism intervenes, replacing the sudden shutdown with a step-decreasing power curve, and performing virtual energy discharge compensation through the energy discharge unit to eliminate temperature overshoot. The thermal inertia energy scheduling mechanism accurately predicts the heat reserve threshold required to reach steady state through the thermal balance inversion algorithm of the energy pre-scheduling unit. At the same time, it relies on the energy discharge unit to monitor the residual heat accumulation status of the heating element in real time. When the difference between the initial heating drive power and the current actual output power exceeds the threshold, it intervenes and adjusts in a timely manner. It replaces the traditional abrupt shutdown method with a step-decreasing power curve. It also eliminates the temperature overshoot problem caused by the thermal inertia of the heating element through virtual energy discharge compensation. It effectively avoids the situation where the interface temperature deviates from the target value due to the continuous release of residual heat after abrupt shutdown. It accurately matches the thermal inertia characteristics of the heating element, making the power adjustment smoother and more in line with the energy release pattern of the heating element. It corrects the initial heating drive power from the energy scheduling level, so that the final output heating drive power is more suitable for the actual temperature control requirements, greatly reducing the probability of temperature overshoot. It further improves the accuracy and stability of the constant temperature control of the hot compress product and ensures that the temperature of the human body contact interface always fits the target temperature.

[0028] Continuing with the actual working conditions of the aforementioned heat therapy product in contact with the human shoulder, the previously calculated estimated value of contact thermal resistance is used. Initial heating drive power Preset target temperature Interface temperature Set the thermal inertia coefficient The formula for calculating the heat reserve threshold in the heat balance inversion algorithm is as follows: The formula for converting the power difference threshold is: (Take time factor) Set the current actual output power. Virtual energy release compensation amount The single-stage step size of the stepped decreasing power curve .

[0029] The heat reserve threshold is calculated based on the heat balance inversion algorithm. Substituting the data, we get: ; Calculate the power difference threshold and substitute the data to get: ; The formula for calculating the actual difference between the initial heating drive power and the current actual output power is as follows: Substituting the data, we get: ; ; The intervention was triggered by the thermal inertial energy scheduling mechanism; The initial heating drive power is corrected in stages using a stepped decreasing step size. The power after the first stage correction is... Power after second-stage correction This continues until the difference between the corrected power and the actual output power approaches the power difference threshold. Virtual energy discharge compensation is performed on the power after the step-decreasing step, and the final heating drive power calculation formula is as follows: (Take the power after the second stage correction) Substituting the data, we get: .

[0030] The final heating drive power is the result of correction by the thermal inertia energy scheduling mechanism. Instead of directly increasing the power from 3.0W to 8.0964W in a step-by-step manner, it uses a gradual decrease to offset the accumulation of residual heat in the heating element. This avoids the sudden increase in heat caused by the power change and the resulting temperature overshoot. Compared with the method of directly outputting the initial heating drive power without scheduling correction, it allows the heat release of the heating element to be more gradual. This ensures that there is no obvious overshoot during the process of the interface temperature increasing from 41℃ to 42℃, and it stably matches the target temperature. This effectively solves the temperature control deviation problem caused by the thermal inertia of the heating element.

[0031] The process by which the thermal inertial energy dispatch mechanism executes a step-decreasing power curve includes: Obtain the preset thermal inertia time constant of the heating element; Calculate the power decrease step size based on the thermal inertia time constant and the current rate of change of the interface temperature data; The stepped decreasing power curve is generated by gradually reducing the initial heating drive power to zero power in steps, where the duration of each step is monotonically positively correlated with the estimated contact thermal resistance. Specific quantitative rules are established for the execution process of the stepped power reduction curve of the thermal inertia energy dispatching mechanism. By presetting the thermal inertia time constant of the heating element and combining it with the current rate of change of the interface temperature, the power reduction step size is accurately calculated. At the same time, the duration of each step is monotonically positively correlated with the estimated contact thermal resistance. This makes the stepped power reduction curve no longer a fixed parameter control, but a complete adaptation to the thermal inertia characteristics of the heating element itself and the actual contact thermal resistance between the current heat therapy product and the human body. This avoids the problem of power reduction being too fast or too slow caused by fixed step size and fixed duration. The rhythm and magnitude of power reduction are highly matched with the heat release law of the heating element and the actual contact thermal resistance state, further improving the scientificity and accuracy of power reduction, maximizing the smoothness of power adjustment, and completely eliminating the possibility of temperature overshoot from the execution level of the stepped curve. This continuously optimizes the control effect of the thermal inertia energy dispatching mechanism, making the final output of heating drive power more in line with the dynamic requirements of actual constant temperature control.

[0032] Continuing with the actual working conditions of the aforementioned heat therapy product in contact with the human shoulder, the previously calculated estimated value of contact thermal resistance is used. Interfacial temperature change rate Initial heating drive power The thermal inertia time constant of the heating element of the heat therapy product is preset. The formula for calculating the power decrease step size is set as follows: (The coefficient 0.02 is the power adjustment coefficient for the compatible heat therapy product, unit: The formula for calculating the duration of the steps is as follows: (Coefficient 100 is the time adjustment coefficient for adapting contact thermal resistance, unit: The stepped power reduction curve needs to gradually decrease from the initial heating drive power to the zero power state.

[0033] Calculate the power decrease step size according to the formula, and substitute the values ​​to get: This step size is a fixed amount of power reduction for each stage; Calculate the duration of each step using the formula, and substitute the values ​​to get: That is, the power after each level of decrease must be maintained for 2.914 seconds before the next level of decrease is performed; The formula for calculating the total number of steps in a step-decreasing sequence is as follows: ( (This is the floor sign), substituting the data, we get: class; Generate the power values ​​for each stage of the stepped decreasing power curve. The power calculation formula for the nth stage is as follows: Such as the first level of power Level 2 power Level 135 power Take 0W as the final decreasing power; The total duration of the stepped power decline curve is determined by the following formula: Substituting the data, we get: That is, the curve takes 393.39 seconds to gradually decrease from the initial power to zero power.

[0034] The step size of this stepped power reduction curve is determined by the thermal inertia of the heating element and the rate of change of the interface temperature. The duration is positively correlated with the estimated contact thermal resistance, which is perfectly suited to the current actual working conditions. Compared with a stepped curve with a fixed step size of 0.5W and a fixed duration of 2s, the precise quantitative stepped curve under this condition allows the power release of the heating element to better match its own thermal inertia. This avoids insufficient heating caused by excessive power reduction and also avoids a sudden drop in heat caused by excessively short duration. It keeps the heat release smooth and completely eliminates the temperature overshoot problem caused by unreasonable power reduction parameters, ensuring that the process of the interface temperature rising to the target temperature is always stable.

[0035] The interface temperature data is multi-point distributed temperature data; the control system also includes a contact state adaptive compensation module. The contact state adaptive compensation module identifies local detached areas based on the contact pressure distribution data. When a local detached area is identified, the control unit shields the temperature acquisition signal corresponding to the local detached area in the adaptive PID calculation, and reconstructs the comprehensive deviation signal based on the pressure gradient distribution of adjacent areas to maintain the constant temperature of the contact area. By setting the interface temperature data to a multi-point distributed acquisition method and adding a contact state adaptive compensation module, the system can accurately identify the local detached areas of the heat therapy product in contact with the human body through contact pressure distribution data. In the adaptive PID calculation, invalid temperature acquisition signals in these areas are shielded. At the same time, the comprehensive deviation signal is reconstructed by regional weighting based on the pressure gradient distribution of adjacent areas. This avoids the abnormal temperature signals of local detached areas interfering with the overall temperature control judgment, and solves the temperature control deviation problem caused by local detachment in traditional temperature acquisition methods. The comprehensive deviation signal accurately reflects only the true temperature state of the contact area, ensuring that the temperature of the area where the heat therapy product is in contact with the human body remains constant. The multi-point distributed temperature acquisition also makes temperature monitoring more comprehensive and accurate, further improving the system's dynamic adaptation capability to different contact states and the regional accuracy of constant temperature control.

[0036] Continuing with the actual working conditions of the aforementioned heat therapy product in contact with the human shoulder, the pre-set dynamic compensation coefficient will be used. Target temperature Ambient temperature The environmental disturbance compensation factor α=0.05 and the temperature change rate damping factor β=2 are used. The interface temperature is set using a 4×4 array multi-point distributed acquisition, with a total of 16 temperature acquisition points. Corresponding to different contact areas on the shoulder, the contact state adaptive compensation module identifies the contact points. The contact pressure value is 0 MPa, which is determined to be a localized detached area; the rest... For the bonding area, the average interface temperature is collected in real time for each bonding area. Average rate of change of interface temperature in the bonding area The formula for reconstructing regional weights is set as follows: ( To determine the contact pressure value for the fitting area i, (This is the sum of pressure values ​​in all bonding areas). The reconstructed comprehensive deviation signal is the weighted average of the deviation signals at each point in the bonding area.

[0037] The contact state adaptive compensation module identifies After defining the local off-body region, the temperature acquisition signals of the two points are directly shielded in the adaptive PID calculation to eliminate the interference of invalid temperature data on the temperature control calculation. The weight value of each bonding region is calculated based on the pressure gradient distribution of adjacent regions, and the sum of the weight values ​​of all bonding regions is then calculated. The formula for calculating the weighted average static deviation of the mating area is: Substituting the data yields ; Calculate the product term of the dynamic compensation coefficient and the reconstructed static deviation, i.e. ; The weighted feedforward term for calculating environmental disturbances is given by the following formula: Substituting the data yields ; The weighted signal term for calculating the temperature trend prediction of the fitted area is given by the following formula: Substituting the data yields ; The reconstructed comprehensive deviation signal is calculated based on the comprehensive deviation signal formula. Substituting the data yields ; If the regional weights are not reconstructed, the off-body region will be... Low temperature data ( The average interface temperature of the 16 points was 40.1℃, and the corresponding comprehensive deviation signal was -1.685℃. This value is significantly different from the actual deviation of the bonding area due to interference from the detached area.

[0038] In this operating condition, the shielding and reconstruction operation of the contact state adaptive compensation module ensured that the comprehensive deviation signal accurately reflected the actual temperature deviation of the shoulder contact area, avoiding the distortion of the comprehensive deviation signal caused by the low temperature data of the detached area. This enabled the subsequent adaptive PID calculation to generate heating drive power based on the actual contact area deviation, ensuring that the temperature of the shoulder contact area could be stably adjusted towards the target temperature of 42℃. The final temperature control deviation of the contact area could be controlled within ±0.2℃, which is far lower than the ±1.0℃ deviation range when shielding and reconstruction were not performed.

[0039] It also includes an independent redundant verification loop, which runs in parallel with the control unit to compare the absolute value of the deviation between the interface temperature data and the target temperature value in real time, and to monitor the fluctuation range of the dynamic compensation coefficient. When the absolute value of the deviation exceeds the first safety threshold or the dynamic compensation coefficient exceeds the second safety threshold, the independent redundant verification loop directly cuts off the power supply circuit of the heating element and simultaneously forces the integral accumulation term of the adaptive PID calculation to freeze. The added independent redundant verification loop operates in parallel with the control unit, which can accurately compare the absolute value of the deviation between the interface temperature data and the target temperature value in real time, and continuously monitor the fluctuation range of the dynamic compensation coefficient. When the absolute value of the deviation exceeds the first safety threshold or the dynamic compensation coefficient exceeds the second safety threshold, the power supply circuit of the heating element can be directly cut off. At the same time, the integral accumulation term of the adaptive PID calculation is forcibly frozen, forming a dual safety protection system that complements the main control unit. This avoids the risk of temperature runaway caused by problems such as main control unit failure, abnormal data acquisition, or parameter calculation deviation. It completely eliminates the safety hazard of overheating and scalding the human body from the hardware and algorithm levels. Moreover, freezing the integral accumulation term can prevent secondary temperature control deviation caused by abnormal accumulation of integral terms after the fault is cleared. This ensures safe shutdown in the case of system failure and temperature control stability after subsequent recovery, and greatly improves the operational safety, reliability, and emergency handling capability of the heating constant temperature control system of the heating product.

[0040] Continuing with the actual working conditions of the aforementioned heat therapy product in contact with the human shoulder, the target temperature is maintained. Dynamic compensation coefficient under normal operating conditions Normal interface temperature The first safety threshold (absolute value of the deviation between interface temperature and target temperature) of the preset independent redundant verification loop is set. The second safety threshold is the fluctuation range of the dynamic compensation coefficient. That is, a dynamic compensation coefficient below 0.5 or above 3.5 is considered exceeding the threshold. The real-time monitoring frequency of the redundant verification loop is set to 10ms / time, and the PID integral cumulative term freezing formula is as follows: ( (This is the time to trigger safety protection), and at the same time, the integral accumulation of the adaptive PID calculation under normal operating conditions is set. .

[0041] First, calculate the monitoring indicators under normal operating conditions. The formula for calculating the absolute value of temperature deviation is: Substituting the data yields The value is less than the first safety threshold of 3℃, and the dynamic compensation coefficient of 2.914 is within the range of the second safety threshold [0.5, 3.5]. The redundant verification circuit does not trigger protection, and the system operates normally. Simulated abnormal operating condition where temperature deviation exceeds the first safety threshold: Due to a malfunction of the temperature acquisition sensor, the interface temperature data suddenly rises to... Calculate the absolute value of the temperature deviation at this time. The independent redundant verification circuit immediately triggers security protection; After the protection is triggered, the redundant verification circuit directly cuts off the power supply to the heating element, stopping its heating operation. Simultaneously, it executes the operation according to the freezing formula, setting the trigger time... The PID integral accumulator term is set to 0, i.e. This eliminates the potential for abnormal accumulation of integral terms; Simulated abnormal operating condition where the dynamic compensation coefficient exceeds the second safety threshold: Due to a malfunction in the multi-dimensional data acquisition module, the contact pressure data acquisition is distorted, causing the dynamic compensation coefficient to surge to [a certain value]. If this value exceeds the upper limit of the second security threshold of 3.5, the independent redundant verification loop will immediately trigger security protection. Under this abnormal operating condition, the redundant verification circuit also directly cuts off the power supply circuit of the heating element to terminate the heating operation. At the same time, it forces the PID integral cumulative term to 0 according to the freeze formula to avoid the abnormal value of the integral term after the fault is recovered from affecting the temperature control accuracy of the subsequent PID calculation. Without this independent redundant verification circuit, the two abnormal operating conditions mentioned above will cause the interface temperature to rise continuously or the temperature control parameters to become seriously distorted, ultimately causing the interface temperature of the hot compress product to exceed the safe range and causing a safety accident of burns to the human body. The timely intervention of the redundant verification circuit can quickly cut off the heating circuit and avoid such safety risks from the root.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A constant temperature control system for a heat therapy product, characterized in that, include: The multi-dimensional data acquisition module is used to acquire in real time interface temperature data, heating element side temperature data, ambient temperature data, heat flux density data, and contact pressure distribution data of the interface between the heat therapy product and the human body. The dynamic thermal resistance compensation model is based on contact pressure distribution data and heat flux density data. It dynamically calculates the estimated contact thermal resistance under the current operating conditions and generates dynamic compensation coefficients based on the estimated contact thermal resistance. The control unit is electrically connected to both the multidimensional data acquisition module and the dynamic thermal resistance compensation model. The control unit is configured as follows: Obtain the preset target temperature value; Based on the deviation between the interface temperature data and the target temperature value, and combined with the dynamic compensation coefficient, a comprehensive deviation signal with time-varying characteristics is constructed. An adaptive PID calculation is performed based on the comprehensive deviation signal to generate the initial heating drive power; The initial heating drive power is corrected by a thermal inertial energy scheduling mechanism, and the final heating drive power is output to control the operation of the heating element.

2. The heating and constant temperature control system for a heat therapy product according to claim 1, characterized in that: The process of generating dynamic compensation coefficients in a dynamic thermal resistance compensation model includes: Obtain the average contact pressure value after spatial integration processing of the contact pressure distribution data; Acquire heat flux density data, interface temperature data, and temperature data on the heating element side; The estimated contact thermal resistance is obtained by performing thermal resistance inversion calculations based on the difference between the interface temperature data and the temperature data on the heating element side, as well as the heat flux density data, and then performing nonlinear corrections based on the average contact pressure value. The dynamic compensation coefficient is calculated based on the deviation rate between the estimated contact thermal resistance and the preset reference thermal resistance.

3. The constant temperature control system for a heat therapy product according to claim 2, characterized in that: The process by which the control unit constructs the comprehensive deviation signal includes: Obtain the static deviation between the interface temperature data and the target temperature value; Ambient temperature data is acquired as a feedforward perturbation signal; The rate of change of interface temperature data over time is used as a temperature trend prediction signal. The comprehensive deviation signal is obtained by fusing the product of static deviation and dynamic compensation coefficient, the weighted value of feedforward disturbance signal, and the weighted value of temperature trend prediction signal.

4. The constant temperature control system for a heat therapy product according to claim 3, characterized in that: Adaptive PID calculation specifically includes: The proportional coefficient is dynamically adjusted based on the spatial dispersion index of the contact pressure distribution data. The spatial dispersion index is obtained by normalizing the variance of the contact pressure distribution data. When the spatial dispersion index is higher than the preset threshold, the proportional coefficient is increased to improve the system response speed. The integral coefficient is adjusted piecewise nonlinearly based on the time accumulation of the comprehensive deviation signal to suppress integral saturation. The differential coefficients are adaptively adjusted according to the fluctuation range of the temperature change rate to suppress system overshoot; The initial heating drive power is obtained by performing proportional, integral, and differential operations on the comprehensive deviation signal combined with the dynamically adjusted proportional coefficient, integral coefficient, and derivative coefficient.

5. The heating and constant temperature control system for a heat therapy product according to claim 4, characterized in that: Thermal inertial energy dispatch mechanisms include: The energy pre-scheduling unit is used to estimate the heat reserve threshold required to reach steady state based on interface temperature data, target temperature value and contact thermal resistance estimate, using a thermal balance inversion algorithm. An energy dissipation unit is used to monitor the residual heat accumulation status of the heating element; The final output heating drive power is obtained in the following way: when the difference between the initial heating drive power and the current actual output power exceeds the heat storage threshold, the thermal inertia energy scheduling mechanism intervenes, replacing the abrupt shutdown with a step-decreasing power curve, and performing virtual energy discharge compensation through the energy discharge unit to eliminate temperature overshoot.

6. The heating and constant temperature control system for a heat therapy product according to claim 5, characterized in that: The process by which the thermal inertial energy dispatch mechanism executes a step-decreasing power curve includes: Obtain the preset thermal inertia time constant of the heating element; Calculate the power decrease step size based on the thermal inertia time constant and the current rate of change of the interface temperature data; The stepped decreasing power curve is generated by gradually reducing the initial heating drive power to zero power in progressively decreasing steps, where the duration of each step is monotonically positively correlated with the estimated contact thermal resistance.

7. The heating and constant temperature control system for a heat therapy product according to claim 6, characterized in that: The interface temperature data is multi-point distributed temperature data; the control system also includes a contact state adaptive compensation module, which identifies local detached areas based on the contact pressure distribution data. When a local detached area is identified, the control unit shields the temperature acquisition signal corresponding to the local detached area in the adaptive PID calculation, and reconstructs the comprehensive deviation signal based on the pressure gradient distribution of adjacent areas to maintain a constant temperature in the contact area.

8. The heating and constant temperature control system for a heat therapy product according to claim 7, characterized in that: It also includes an independent redundant verification loop, which operates in parallel with the control unit to compare the absolute value of the deviation between the interface temperature data and the target temperature value in real time, and to monitor the fluctuation range of the dynamic compensation coefficient. When the absolute value of the deviation exceeds the first safety threshold or the dynamic compensation coefficient exceeds the second safety threshold, the independent redundant verification loop directly cuts off the power supply circuit of the heating element and simultaneously forces the integral accumulation term of the adaptive PID calculation to freeze.

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