A metabolic cabin human body data measurement method and system based on comfort

Abstract

The present invention discloses a method and system for measuring human body data in a metabolic cabin based on comfort. The method comprises a data acquisition system for acquiring PMV index parameters within the cabin; a PMV index data processing system for establishing a PMV index calculation model based on PMV index calculation standards and determining temperature and air flow rate based on a nonlinear programming equation; a metabolic data processing system for determining the value of air volume V according to temperature and air flow rate, and simultaneously calculating the energy consumption rate MR using the updated value of air volume V; and a control module for adjusting the temperature and wind speed of the cabin air conditioning system according to temperature and air flow rate. The present invention resolves the mutual constraints between the PMV index calculation model and the metabolic cabin system, and can simultaneously detect the PMV index value within the metabolic cabin, thereby adjusting the cabin environment, ensuring that the subject remains in a thermoneutral environment during system testing and improving the accuracy of the detected metabolic data.

Description

Technical Field

[0001] The present invention belongs to the field of metabolic thermal management, and in particular relates to a method and system for measuring human body data in a metabolic cabin based on comfort. Background Art

[0002] The 24-hour EE components measured using indirect calorimetry (metabolic chamber) include the following: (1) sleeping metabolic rate (SMR), (2) resting metabolic rate (RMR), (3) thermic effect of food (TEF), and (4) EE (energy expenditure) associated with physical activity (PAEE). With appropriate experimental design, other components of 24-hour EE, such as excess post-exercise oxygen consumption, can also be measured.

[0003] Resting metabolic rate (BMR) is the EE rate when completely at rest; it represents the EE required to maintain vital functions, such as basic chemical reactions of the body, and is the primary contributor (60% to 75%) to the 24-hour EE measured in an indirect calorimeter. BMR is typically measured using a ventilated hood, and the strictest definition of BMR requires that the individual be in a post-absorptive state (10-12 hours without consuming high-calorie food or beverages), while the body is undisturbed, awake, and in a thermoneutral environment.

[0004] At the same time, the projected mean thermal sensation index (PMV index) is used to evaluate the comfort of the environment. It includes the following six basic parameters in the classic thermal balance model of human thermal comfort: M (human metabolic rate), I cl (Clothing thermal resistance), t(air temperature), t r (radiant temperature), RH (relative humidity) and v (air velocity), the expected average thermal sensation index can also be expressed as the following function:

[0005] PMV=f(M,I cl ,t,t r , RH, v)

[0006] Figure 6The figure shows how the PMV index is affected by metabolic rate when the thermal resistance of clothing is equal to 1clo. The horizontal axis represents temperature and the vertical axis represents PMV index. The curves from top to bottom represent the changes in PMV index when the metabolic rate changes from 0.9met, 1.1met, 1.3met, and 1.5met, respectively. It can be seen that a change in metabolic rate from 0.9met to 1.5met can cause the thermoneutral temperature (the temperature when the PMV index equals 0) to change by more than 3.2K, or about 1.5 units of PMV index difference. Accurate description of human metabolic rate is the foundation of thermal comfort research and its importance in thermal comfort prediction is unquestionable. Existing thermal comfort prediction systems can be used for environmental regulation in different scenarios, but in research and practice, metabolic rate is often a rough assessment. Most studies in the field of thermal comfort rely on simple activity logs to estimate metabolic rate. This method treats metabolic rate as a constant value based on the individual and current activity level. It is obtained by looking up the human energy metabolic rate table for different activities in Table 1 below:

[0007] Table 1

[0008]

[0009] It can be seen that the popular methods in the above thermal comfort research and practice are not accurate enough. In particular, when considering individual differences in BMI, gender, age, pregnancy and menopause status, and non-steady-state scenarios, it is no longer possible to maintain any accuracy in general thermal comfort modeling. In order to solve the uncertainty of metabolic rate estimation, it is usually achieved by using the Newton method (taking the clothing surface temperature t cl The Newton method integrates the calculated metabolic rate value into the calculation of the PMV index, making the PMV index closer to the true value. However, the predicted value of the metabolic rate in the Newton method is determined based on mathematical inference. Compared with the direct measurement of the metabolic rate, its accuracy is not perfect, which reduces the validity of the calculated value of the PMV index.

[0010] This shows the relationship between the predicted mean thermal sensation index (PMV index) and human metabolic rate measurement. In order to accurately measure thermal comfort in a certain type of building, on-site measurements of human metabolic rate characteristics are often introduced or the building is designed to have specific metabolic rate characteristics. However, the mean thermal sensation index (PMV index) is rarely introduced into human metabolic rate measurement. This is not only because the human metabolic rate measurement system is relatively closed, but also because changes in the air-conditioning system cause distortion of metabolic data. At the same time, how to adjust the air-conditioning to change the temperature and wind speed according to changes in the scene is also a problem.

[0011] However, maintaining environmental thermal neutrality and placing individuals in a comfortable environment are very important for human metabolic measurements. It is also necessary to set up a comfort evaluation system to detect the PMV index around the subjects and then adjust the environment of the metabolic chamber. Summary of the Invention

[0012] The purpose of the present invention is to provide a metabolic cabin human body data measurement method and system based on comfort in order to solve the above-mentioned technical problems. The method is applicable to a metabolic cabin system and is based on a comfort evaluation system of an estimated average thermal sensation index to maintain the thermal neutrality of the environment in real time, thereby improving the accuracy of metabolic data.

[0013] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0014] (1) Metabolic Chamber

[0015] Metabolic chambers, ventilation hoods, and masks are all used to indirectly measure human energy expenditure. The main advantage of metabolic chambers is that the subjects are not affected by body-worn instruments; therefore, accurate measurements can be made continuously for 24 hours or longer. The principle of measuring human energy expenditure is mainly based on: "The rate of increase in the volume of gas in the chamber = the rate of increase in the volume flow of gas entering the chamber + the rate at which the subject produces gas volume - the rate of increase in the volume flow of gas out of the chamber." Therefore, the rate of change of the gases representing energy expenditure (oxygen and carbon dioxide) is calculated as follows:

[0016]

[0017] Where VO2 is the oxygen metabolic consumption rate, VCO2 is the carbon dioxide metabolic production rate, and F is the countercurrent air flow entering the cabin, which is set by the mass flow controller and is the gas flow under standard conditions. are the concentrations of oxygen and carbon dioxide entering and flowing out of the cabin, respectively. To pre-set concentration, The concentrations of oxygen and carbon dioxide in the outflowing air stream are detected by a gas analyzer; is the time variation of the concentration of oxygen and carbon dioxide in the cabin air; V is the volume of air in the cabin under standard conditions; N is the Haldane coefficient;

[0018] The above Haldane coefficient is used to convert the reverse air flow rate and the outflow air flow rate. The conversion standard is to assume that the other gases in the metabolic chamber system do not participate in the reaction except oxygen and carbon dioxide, and obtain Therefore, by fixing the concentrations of oxygen and carbon dioxide in the countercurrent air and ensuring that the metabolic cabin is sealed (the pressure differential sensor can be used to balance the air pressure inside and outside the cabin), the measurement of human metabolic energy can be achieved, and then the metabolic cabin can be set up as follows. It should be pointed out that the metabolic cabin described in the present invention is not a single type or fixed-function metabolic cabin body, it can be a building with specific metabolic rate characteristics. The metabolic cabin system of the present invention includes a cabin, a mass flow controller, a gas analyzer and a pressure differential sensor; the cabin is sealed, and a countercurrent air flow is provided to the cabin, and air is extracted from the cabin at the other end to form an outflow air flow, the mass flow controller detects the flow rate of the countercurrent air flow, the gas analyzer detects the concentrations of carbon dioxide and oxygen in the outflow air flow, and the pressure differential sensor is used to balance the air pressure inside and outside the cabin. Of course, it is also necessary to install air conditioning for the experience of the subjects in the metabolic cabin.

[0019] (2) Pre-correction of metabolic data

[0020] The human metabolic rate (M) is determined by dividing the energy expenditure rate (MR) by the body surface area (BSA). (Note that the energy expenditure rate (MR) (L / min) must be converted to kcal / min and then to J / s for uniform calculations.) Energy expenditure (MR) = 3.941 * VO2 + 1.106 * VCO2. The body surface area (BSA) is determined as follows:

[0021] BSA=0.0061*L+0.0124*G-0.0099

[0022] Where L is the height of the subject (cm), G is the weight of the subject (kg), VO2 (L / min) is the oxygen metabolic consumption rate, VCO2 (L / min) is the carbon dioxide metabolic production rate, not just the test data The main influencing factors include the gas volume V in the cabin, which is related to temperature, pressure, and gas convergence velocity (air velocity). After the differential pressure sensor is set to balance the pressure inside and outside the cabin, it is mainly related to temperature and air velocity. Therefore, in order to reduce the impact of environmental changes on metabolic data, a set of gas washout tests will be performed before metabolic measurement. While solving the gas volume V in the cabin, the gas volume V in the cabin under different environments (temperature, air velocity) is also fitted to obtain the accurate value of the gas volume V in the cabin under different environments. The specific gas washout test is as follows:

[0023] Step T100 , first obtaining the temperature t and air flow rate v in the cabin, and then injecting a certain amount of carbon dioxide into the cabin so that the concentration levels of oxygen and carbon dioxide in the cabin are different from those of fresh air;

[0024] Step T200: Fresh air is continuously introduced into the cabin via a mass flow controller, and the concentration of oxygen or carbon dioxide flowing out of the cabin is continuously monitored via a gas analyzer; the difference between the concentration of the oxygen or carbon dioxide flowing out of the cabin and the concentration of the corresponding gas in the fresh air decreases as the monitoring duration continues, until the concentration of the oxygen or carbon dioxide flowing out of the cabin is consistent with the concentration in the fresh air.

[0025] Step T300: Invert the cabin air volume V by collecting the flow rate of fresh air flowing into the cabin and the concentration of oxygen or carbon dioxide flowing out of the cabin and solving a zero-input differential equation. The zero-input differential equation is:

[0026]

[0027] is the concentration of carbon dioxide flowing out of the cabin, measured by a gas analyzer, F is the flow rate of fresh air flowing into the cabin, set by a mass flow controller, which is the gas flow rate under standard conditions, A and C are fitting indices, V is the air volume in the cabin under standard conditions at a certain temperature t and air flow rate v, and t is the time constant; according to the above-mentioned gas washout test method, multiple experiments are carried out in sequence to obtain multiple groups of samples including temperature t, air flow rate v and corresponding cabin air volume V, and the function of cabin air volume V with respect to temperature t and air flow rate v is obtained by machine learning or two-dimensional fitting.

[0028] (3) Predicted Mean Thermal Perception Index (PMV Index)

[0029] The national standard (GB / T 18049-2000) provides the determination of the PMV index and PPD index in a moderate thermal environment and the provisions for thermal comfort conditions. The PMV index can be calculated according to the following formula:

[0030] PMV=(0.303e -0.036M +0.028){(MW)-3.05*10 -3 *[5733-6.99(MW)-p a ]-0.42*[(MW)-58.15]-1.7*10 -5 M(5867-p a )-0.0014M(34-t)-3.96*10 -8 f cl [(t cl +273) 4 -(t r +273) 4 ]-f cl h c (t cl -t)}

[0031] Among them, t cl =35.7-0.028(MW)-I cl *{3.96*10 -8 f cl [(t cl +273) 4 -(t r +273) 4 ]-f cl h c (t el -t)};

[0032]

[0033]

[0034] Among them, PMV index is the expected average thermal sensation index; M is the human metabolic rate, W is the work done by the human body, I cl is the thermal resistance of clothing, f cl is the ratio of the clothed body surface area to the naked body surface area, t is the temperature, t r is the radiation temperature, v is the air velocity, p a is the water vapor partial pressure, h c is the convective heat transfer coefficient, t cl is the surface temperature of the garment.

[0035] In order to obtain the calculation parameters of the PMV index in the cabin, in addition to installing the necessary mass flow controller, gas analyzer, pressure difference sensor and necessary regulating device air conditioner in the cabin, a temperature sensor should also be installed to measure the temperature t, and a black ball thermometer should be installed to measure the radiation temperature t r , the wind speed probe is used to measure the air velocity v, and the humidity sensor is used to measure and calculate the water vapor partial pressure p a The required relative humidity RH is about I cl The thermal resistance of clothing is obtained from Table E1 (thermal resistance of various typical combinations of clothing) in the national standard (GB / T18049-2000); for the environmental regulation in the metabolic chamber, it can be seen that when the external work is fixed, PMV = f(M, I cl ,t,t r , RH, v); and t r RH is relatively fixed in the metabolic chamber. RH is related to the subject's breathing and the water vapor in the fresh air entering the chamber. Adjusting RH is unrealistic and is also related to the measurement of the entire chamber system. cl The amount It is small, so the installed air conditioner can be used to adjust the temperature t and air flow rate v, thereby changing the cabin environment.

[0036] The formula for the PMV index given in the national standard (GB / T 18049-2000) is relatively complex. Although the national standard (GB / T 18049-2000) provides a method for calculating the PMV index by computer, the estimates of the human metabolic rate M and the human body's external work W are quite different from those in the metabolic chamber system and cannot be directly used. Therefore, a PMV index calculation model is re-established based on the PMV index calculation standard as follows:

[0037] PMV=a*[(MW)-HE c -C res -E res ](a=0.303*e -0.306M +0.028), where

[0038] E c =3.05*10 -3 *[5733-6.99(MW)-p a ]-0.42*[(MW)-58.15]

[0039] C res =0.0014M(34-t)

[0040] E res =1.7*10 -5 M(5867-p a )

[0041] H=3.96*10 -8 f cl [(t cl +273) 4 -(t r +273) 4 ]+f cl h c (t cl -t)

[0042] H is the sensitive heat loss of the human body, E c is the heat exchange through evaporation on the skin, C res is the convective heat exchange of breathing, E res The evaporative heat exchange of respiration is determined by the temperature t, air velocity v, metabolic rate M and external work W to determine the human body's sensitive heat loss function H = k1 (t, v, M, W), where H = k1 (t, v, M, W) means that H is a function k1 of the variables t, v, M, W; the heat exchange function E generated by evaporation on the skin is determined by the temperature t, metabolic rate M and external work W. c = k2(t, M, W); Determine the convective heat exchange C of respiration by temperature t and metabolic rate Mres = k3(t, M); Determine the evaporative heat exchange E of respiration by temperature t and metabolic rate M res =k4(t, M), and then the PMV index calculation model is obtained:

[0043] PMV=k(t,v,M,W)=a*[(MW)-k1(t,v,M,W)-k2(t,M,W)-k3(t,M)-k4(t,M)]

[0044] The heat transfer function E generated by evaporation c , Evaporative heat exchange of breathing E res The water vapor partial pressure p a Equal to RH*P b , where P b is the partial pressure of saturated water vapor, P b The value of can be calculated by the following Goff-Grech formula, which is as follows (T ≥ 273.15K):

[0045]

[0046] In addition, the national standard (GB / T 18049-2000) gives a value around 0 for the external work done by the human body, but this system cannot be applied when measuring the energy expenditure EE related to physical activity in the metabolic chamber system. Therefore, the external work W can be determined based on the change in the mechanical energy of the human body's center of gravity based on kinematics, such as Figure 4 As shown, most of the subjects in the metabolic chamber system are in sitting, walking or running states. For the calculation of mechanical work for walking people, the center of gravity of the person is highest when standing on one leg and lowest when both feet are in contact with the ground. The center of gravity difference is h, the subject's leg length is l, and the stride length is s.

[0047]

[0048] The average power density (work done externally) to overcome gravity can then be calculated as follows:

[0049]

[0050] where v a is the speed at which the subject walks or runs, and 0 for sitting or standing. is the acceleration due to gravity, G is the weight of the subject (kg), and BSA represents the body surface area. The external work W can then be predicted based on the type of test (motion state) that the subject will undergo.

[0051] (IV) Metabolic measurements based on the predicted mean thermal sensation index (PMV index):

[0052] It is very important to detect the PMV index and keep the subjects in the cabin in a thermally neutral environment in real time. The predicted dissatisfaction rate (PPD) given by the national standard (GB / T 18049-2000) can qualitatively predict the dissatisfaction rate of the surrounding thermal environment feeling too cold or too hot. That is, in different levels of thermal sensation scale, the number of people who evaluate the environmental comfort as cold, hot, warm, and cool, and the rest of the people evaluate the thermal environment as slightly cool, slightly warm, or moderately hot. The functional relationship between the PMV index and PPD is:

[0053]

[0054] It can be seen that when the absolute value of the PMV index is greater than 0.5, the number of people who are dissatisfied with the environmental comfort will increase rapidly. Since the PMV index is at a stationary point, the PPD value is 5. In view of the high comfort required by the metabolic cabin, the PPD is obtained to be 6, that is, under the same environment, when 94% of the people are satisfied with the environmental comfort, the PMV index solved is between ±0.2. Therefore, the environmental comfort threshold described in the present invention can be set to ±0.2.

[0055] Regarding the changes in the human metabolic rate M based on the amount of exercise proposed in the present invention, the human energy metabolic rate table in the national standard (GB / T18049-2000) can be referred to, and the changes in the human metabolic rate M' can be predicted by the type of test (exercise state) to be performed by the subject. Of course, it is also necessary to reduce the impact of environmental changes on the metabolic chamber system. The smaller the environmental change, the better. Therefore, when the type of test to be performed by the subject changes or the amplitude of exercise further changes, the environment is pre-adjusted by existing environmental factors and the predictable human metabolic rate M' and the external work W of the human body. The adjustment method is to solve the nonlinear programming equation to obtain the predicted temperature t' and the predicted air flow rate v':

[0056]

[0057]

[0058] Where t0 and v0 are the cabin temperature and air flow rate obtained before the change of motion state, W1 is the work W done by the human body determined according to the motion state of the subject in step S200, M0 and M1 are the minimum and maximum values ​​of the change of the human metabolic rate M based on the amount of exercise; solving the nonlinear programming equation is to solve the predicted temperature t' and predicted air flow rate v' that meet the conditions, the initial values ​​of x and y are X0 = t0, Y0 = v0, and the nonlinear programming equation is is the objective function, and To meet the conditions; in addition, since the changes in the work W done by the human body are only for the values ​​of the two motion states, and the purpose is to adapt to the situation after the motion state changes, the value of the work W done by the human body is fixed to the work W done by the human body after the motion state changes, rather than before or limited to between the two, but the human metabolic rate M is continuously changing, not just for the values ​​of the two motion states, so the metabolic rate M needs to be limited to the minimum and maximum values ​​of the two motion states; and then the temperature and wind speed of the air conditioner in the cabin are adjusted according to the predicted temperature t' and the predicted air flow rate v', but the predicted human metabolic rate M, i.e. M0 and M1, is based on the amount of exercise, which is different from the actual human metabolic rate M, so it is necessary to detect the actual human metabolic rate M after the subject's motion state changes, and at this time the gas volume V in the cabin for calculating the actual human metabolic rate M has already occurred. If a change occurs, the function of the air volume V in the cabin with respect to the temperature t and the air flow rate v is obtained through machine learning or two-dimensional fitting in the "pre-correction of metabolic data", and then the existing metabolic data is corrected to obtain the precise value M of the human metabolic rate. Then, the precise value M1 of the human metabolic rate after the subject's motion state changes and the external work W1 in the current state are obtained through the metabolic cabin system. The predicted temperature t' and the predicted air flow rate v' are substituted into the PMV index calculation model to update the PMV index value. At this time, when the PMV index value is between the thresholds, it means that the adjustment is successful and the adjustment is ended. When the PMV index value is not between the thresholds, there are two situations. One is caused by the prediction of the metabolic rate M, and the other is that the metabolic rate M value is too large or the external work is too large to find a PMV index value that meets the threshold, so a larger adjustment of the environment is required. The adjustment method is as follows:

[0059] After obtaining the precise value M1 of the human metabolic rate after the subject's motion state changes and the human body's external work W1 as input, the PMV index calculation model established is used to solve the extreme value of |PMV|, obtain the extreme temperature t″ and the extreme air flow rate v″, and finally adjust the temperature and wind speed of the air conditioner in the cabin according to the extreme temperature t″ and the extreme air flow rate v″. Among them, |PMV| represents the absolute value of the PMV index calculation model. Because the highest comfort is a practical requirement after establishing the |PMV| model, the extreme value solved is the most comfortable index in the current environment. When solving the extreme value of the |PMV| model, there are only two variables, temperature t and air flow rate v. Therefore, the gradient matrix can be solved by the Newton optimal method of multi-dimensional variables, and the extreme value condition of the |PMV| model is when the gradient is 0.

[0060] Compared with the existing technology, the beneficial effects of the present invention are embodied in:

[0061] (1) The present invention solves the mutual constraints between the PMV index calculation model and the metabolic chamber system, and can achieve thermal neutrality under the condition of relatively small changes in environmental factors, thereby minimizing the impact on the detection of the metabolic chamber system;

[0062] (2) The PMV index calculation model established by the present invention can solve the value with the minimum change to environmental factors through nonlinear programming equations;

[0063] (3) The present invention can detect the PMV index value in the metabolic chamber in real time, and then adjust the environment in the chamber to ensure that the subject remains in a thermoneutral environment during system detection, thereby improving the accuracy of the detected metabolic data. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 Schematic diagram of the metabolic cabin human body data measurement system based on comfort level of the present invention;

[0065] Figure 2 Schematic diagram of metabolic rate changes under different exercise states;

[0066] Figure 3 This is a schematic diagram of oxygen consumption under a single exercise load in a submaximal exercise test;

[0067] Figure 4 Schematic diagram of kinematic solution for external work W;

[0068] Figure 5 This is a flow chart of the method for measuring human body data in a metabolic cabin based on comfort level of the present invention;

[0069] Figure 6 Schematic diagram of the effects of different temperatures and metabolic rates on the PMV index. DETAILED DESCRIPTION

[0070] The present invention will be further described in detail below with reference to the embodiments in the accompanying drawings, but this does not constitute any limitation to the present invention.

[0071] The present invention aims to add a system for detecting the comfort index to the metabolic cabin detection system, detect the PMV index value in the metabolic cabin, and then adjust the cabin environment, and then design a metabolic cabin human body data measurement system based on comfort. Figure 1 Shown, including:

[0072] The data acquisition system is used to obtain the parameters required to calculate the PMV index in the cabin. The PMV index parameters in the cabin include the radiation temperature t r , temperature t, air velocity v, human metabolic rate M, human external work W, humidity RH and the thermal resistance of the subject's clothing in the cabin I cl ;

[0073] Average thermal sensation index data processing system, used to establish a PMV index calculation model according to the PMV index calculation standard, and determine the temperature and air flow rate according to the nonlinear programming equation;

[0074] a metabolic data processing system for determining a value of an air volume V according to the temperature and the air flow rate, and calculating an energy consumption rate MR according to the updated value of the air volume V;

[0075] The control module is used to adjust the temperature and wind speed of the cabin air conditioner according to the temperature and air flow rate, and should also have the function of displaying and storing environmental parameters.

[0076] The principles of the present invention include:

[0077] (1) Metabolic Chamber

[0078] Metabolic chambers, ventilation hoods, and masks are all used to indirectly measure human energy expenditure. The main advantage of metabolic chambers is that the subjects are not affected by body-worn instruments; therefore, accurate measurements can be made continuously for 24 hours or longer. The principle of measuring human energy expenditure is mainly based on: "The rate of increase in the volume of gas in the chamber = the rate of increase in the volume flow of gas entering the chamber + the rate at which the subject produces gas volume - the rate of increase in the volume flow of gas out of the chamber." Therefore, the rate of change of the gases representing energy expenditure (oxygen and carbon dioxide) is calculated as follows:

[0079]

[0080] Where VO2 is the oxygen metabolic consumption rate, VCO2 is the carbon dioxide metabolic production rate, and F is the countercurrent air flow entering the cabin, which is set by the mass flow controller and is the gas flow under standard conditions. are the concentrations of oxygen and carbon dioxide entering and flowing out of the cabin, respectively. To pre-set concentration, The concentrations of oxygen and carbon dioxide in the outflowing air stream are detected by a gas analyzer; is the time variation of the concentration of oxygen and carbon dioxide in the cabin air; V is the volume of air in the cabin under standard conditions; N is the Haldane coefficient;

[0081] The above-mentioned Haldane coefficient N is used to convert the countercurrent air flow rate and the outflow air flow rate. The conversion standard is to assume that the other gases in the metabolic chamber system do not participate in the reaction except oxygen and carbon dioxide, and obtain Therefore, fixing the concentrations of oxygen and carbon dioxide in the countercurrent air and ensuring the sealing of the metabolic cabin (the pressure differential sensor can be used to balance the air pressure inside and outside the cabin) can realize the measurement of human metabolic energy, and then the metabolic cabin can be set up as follows (the metabolic cabin pointed out in the present invention is not a single type or a fixed-function metabolic cabin, it can be a building with specific metabolic rate characteristics). The metabolic cabin system of the present invention includes a cabin, a mass flow controller, a gas analyzer and a pressure differential sensor; the cabin is sealed, and a countercurrent air flow is provided to the cabin, and air is extracted from the cabin at the other end to form an outflow air flow. The mass flow controller detects the flow rate of the countercurrent air flow, the gas analyzer detects the concentrations of carbon dioxide and oxygen in the outflow air flow, and the pressure differential sensor is used to balance the air pressure inside and outside the cabin. Of course, it is also necessary to install air conditioning for the experience of the subjects in the metabolic cabin.

[0082] (2) Pre-correction of metabolic data

[0083] The human metabolic rate (M) is determined by dividing the energy expenditure rate (MR) by the body surface area (BSA). (Note that the energy expenditure rate (MR) (L / min) must be converted to kcal / min and then to J / s for uniform calculations.) Energy expenditure (MR) = 3.941 * VO2 + 1.106 * VCO2. The body surface area (BSA) is determined as follows:

[0084] BSA=0.0061*L+0.0124*G-0.0099

[0085] Where L is the height of the subject (cm), G is the weight of the subject (kg), VO2 (L / min) is the oxygen metabolic consumption rate, VCO2 (L / min) is the carbon dioxide metabolic production rate, not just the test data (F, ), among which the main influencing factors include the gas volume V in the cabin. The gas volume V in the cabin is related to temperature, pressure, and gas convergence velocity (air flow rate). After the differential pressure sensor is set to balance the air pressure inside and outside the cabin, it is mainly related to temperature and air flow rate. Therefore, in order to reduce the impact of environmental changes on metabolic data, a set of gas washout tests will be performed before metabolic measurement. While solving the gas volume V in the cabin, the gas volume V in the cabin under different environments (temperature, air flow rate) is also fitted to obtain the accurate value of the gas volume V in the cabin under different environments. The specific gas washout test includes the following steps:

[0086] Step T100 , first obtaining the temperature t and air flow rate v in the cabin, and then injecting a certain amount of carbon dioxide into the cabin so that the concentration levels of oxygen and carbon dioxide in the cabin are different from those of fresh air;

[0087] Step T200: Fresh air is continuously introduced into the cabin via a mass flow controller, and the concentration of oxygen or carbon dioxide flowing out of the cabin is continuously monitored via a gas analyzer; the difference between the concentration of the oxygen or carbon dioxide flowing out of the cabin and the concentration of the corresponding gas in the fresh air decreases as the monitoring duration continues, until the concentration of the oxygen or carbon dioxide flowing out of the cabin is consistent with the concentration in the fresh air.

[0088] Step T300: Invert the cabin air volume V by collecting the flow rate of fresh air flowing into the cabin and the concentration of oxygen or carbon dioxide flowing out of the cabin and solving a zero-input differential equation. The zero-input differential equation is:

[0089]

[0090] is the concentration of carbon dioxide flowing out of the cabin, measured by a gas analyzer, F is the flow rate of fresh air flowing into the cabin, set by a mass flow controller, which is the gas flow rate under standard conditions, A and C are fitting indices, V is the air volume in the cabin under standard conditions at a certain temperature t and air flow rate v, and t is the time constant; according to the above-mentioned gas washout test method, multiple experiments are carried out in sequence to obtain multiple groups of samples including temperature t, air flow rate v and corresponding cabin air volume V, and the function of cabin air volume V with respect to temperature t and air flow rate v is obtained by machine learning or two-dimensional fitting.

[0091] (3) Predicted Mean Thermal Perception Index (PMV Index)

[0092] The national standard (GB / T 18049-2000) provides the determination of the PMV index and PPD index in a moderate thermal environment and the provisions for thermal comfort conditions. The PMV index can be calculated according to the following formula:

[0093] PMV=(0.303e -0.036M +0.028){(MW)-3.05*10 -3 *[5733-6.99(MW)-p a ]-0.42*[(MW)-58.15]-1.7*10 -5 M(5867-p a )-0.0014M(34-t)-3.96*10 -8 f cl [(t cl +273) 4 -(t r +273) 4 ]-f cl h c (t cl -t)}

[0094] Among them, t cl =35.7-0.028(MW)-I cl *{3.96*10 -8 f cl [(t cl +273) 4 -(t r +273) 4 ]-f cl h c (t cl -t)};

[0095]

[0096]

[0097] Among them, PMV index is the expected average thermal sensation index; M is the human metabolic rate, W is the work done by the human body, I cl is the thermal resistance of clothing, f cl is the ratio of the clothed body surface area to the naked body surface area, t is the temperature, t r is the radiation temperature, v is the air velocity, p a is the water vapor partial pressure, h c is the convective heat transfer coefficient, t cl is the surface temperature of the garment.

[0098] In order to obtain the calculation parameters of the PMV index in the cabin, in addition to installing the necessary mass flow controller, gas analyzer, pressure difference sensor and necessary regulating device air conditioner in the cabin, a temperature sensor should also be installed to measure the temperature t, and a black ball thermometer should be installed to measure the radiation temperature t r , the wind speed probe is used to measure the air velocity v, and the humidity sensor is used to measure and calculate the water vapor partial pressure p a The required relative humidity RH is about I cl The thermal resistance of clothing is obtained from Table E1 (thermal resistance of various typical combinations of clothing) in the national standard (GB / T18049-2000); for the environmental regulation in the metabolic chamber, it can be seen that when the external work is fixed, PMV = f(M, I cl ,t,t r , RH, v); and t r RH is relatively fixed in the metabolic chamber. RH is related to the subject's breathing and the water vapor in the fresh air entering the chamber. Adjusting RH is unrealistic and is also related to the measurement of the entire chamber system. cl The amount It is small, so the installed air conditioner can be used to adjust the temperature t and air flow rate v, thereby changing the cabin environment.

[0099] The formula for the PMV index given in the national standard (GB / T 18049-2000) is relatively complex. Although the national standard (GB / T 18049-2000) provides a method for calculating the PMV index by computer, the estimates of the human metabolic rate M and the human body's external work W are quite different from those in the metabolic chamber system and cannot be directly used. Therefore, a PMV index calculation model is re-established based on the PMV index calculation standard as follows:

[0100] PMV=a*[(MW)-HE c -C res -E res ](a=0.303*e -0.306M +0.028),

[0101] in,

[0102] E c =3.05*10 -3 *[5733-6.99(MW)-p a ]-0.42*[(MW)-58.15]

[0103] C res =0.0014M(34-t)

[0104] E res =1.7*10 -5 M(5867-p a )

[0105] H=3.96*10 -8 f cl [(t cl +273) 4 -(t r +273) 4 ]+f cl h c (t cl -t)

[0106] Among them, H is the sensitive heat loss of the human body, E c is the heat exchange through evaporation on the skin, C res is the convective heat exchange of breathing, E res The evaporative heat exchange of respiration is determined by the temperature t, air velocity v, metabolic rate M and external work W to determine the human body's sensitive heat loss function H = k1 (t, v, M, W), where H = k1 (t, v, M, W) means that H is a function k1 of the variables t, v, M, W; the heat exchange function E generated by evaporation on the skin is determined by the temperature t, metabolic rate M and external work W. c= k2(t, M, W); Determine the convective heat exchange C of respiration by temperature t and metabolic rate M res = k3(t, M); Determine the evaporative heat exchange E of respiration by temperature t and metabolic rate M res =k4(t, M), and then the PMV index calculation model is obtained:

[0107] PMV=k(t,v,M,W)=a*[(MW)-k1(t,v,M,W)-k2(t,M,W)-k3(t,M)-k4(t,M)]

[0108] a=0.303*e -0.306M +0.028

[0109] The heat transfer function E generated by evaporation c , Evaporative heat exchange of breathing E res The water vapor partial pressure p a Equal to RH*P b , where P b is the partial pressure of saturated water vapor, P b The value of can be calculated by the following Goff-Grech formula, which is as follows (t represents the indoor temperature and t ≥ 273.15K):

[0110]

[0111] In addition, the national standard (GB / T 18049-2000) gives a value around 0 for the external work done by the human body, but this system cannot be applied when measuring the energy expenditure EE related to physical activity in the metabolic chamber system. Therefore, the external work W can be determined based on the change in the mechanical energy of the human body's center of gravity based on kinematics, such as Figure 4 As shown, most of the subjects in the metabolic chamber system are in sitting, walking or running states. For the calculation of mechanical work for walking people, the center of gravity is highest when standing on one leg and lowest when both feet are in contact with the ground. The center of gravity difference is h, the subject's leg length is 1, and the stride length is s.

[0112]

[0113] The average power density (work done externally) to overcome gravity can then be calculated as follows:

[0114]

[0115] where v a is the speed at which the subject walks or runs, and 0 for sitting or standing. is the acceleration due to gravity, G is the weight of the subject (kg), and BSA represents the body surface area. The external work W can then be predicted based on the type of test (motion state) that the subject will undergo.

[0116] (IV) Metabolic measurement based on the predicted mean thermal sensation index (PMV index)

[0117] It is very important to detect the PMV index and keep the subjects in the cabin in a thermally neutral environment in real time. The predicted dissatisfaction rate (PPD) given by the national standard (GB / T 18049-2000) can qualitatively predict the dissatisfaction rate of the surrounding thermal environment feeling too cold or too hot. That is, in different levels of thermal sensation scale, the number of people who evaluate the environmental comfort as cold, hot, warm, and cool, and the rest of the people evaluate the thermal environment as slightly cool, slightly warm, or moderately hot. The functional relationship between the PMV index and PPD is:

[0118]

[0119] It can be seen that when the absolute value of the PMV index is greater than 0.5, the number of people who are dissatisfied with the environmental comfort will increase rapidly. Since the PMV index is at a stationary point, the PPD value is 5. In view of the high comfort required by the metabolic cabin, the PPD is obtained to be 6, that is, under the same environment, when 94% of the people are satisfied with the environmental comfort, the PMV index solved is between ±0.2. Therefore, the environmental comfort threshold described in the present invention can be set to ±0.2.

[0120] Regarding the change of human metabolic rate M based on the amount of exercise proposed in the present invention, the human energy metabolic rate table in the national standard (GB / T18049-2000) can be referred to, and then the change of human metabolic rate M' can be predicted by the type of test (exercise state) to be performed by the subject. Of course, it is also necessary to reduce the impact of environmental changes on the metabolic chamber system. The smaller the environmental change, the better. Therefore, when the type of test to be performed by the subject changes or the amplitude of exercise changes further, the environment is pre-adjusted by the existing environmental factors and the predictable human metabolic rate M' and the external work W of the human body. The adjustment method is as follows: Figure 5 As shown, the predicted temperature t′ and the predicted air velocity v′ are obtained by solving the nonlinear programming equation:

[0121]

[0122]

[0123] Where t0 and v0 are the cabin temperature and air velocity obtained before the change of motion state, P represents the PMV index threshold, W1 is the work W done by the human body determined according to the motion state of the subject in step S200, M0 and M1 are the minimum and maximum values ​​of the change of the human metabolic rate M based on the amount of exercise; solving the nonlinear programming equation is to solve the predicted temperature t' and predicted air velocity v' that meet the conditions, the initial values ​​of x and y are X0 = t0, Y0 = v0, and in the nonlinear programming equation is the objective function, and To meet the conditions; in addition, since the changes in the work W done by the human body are only for the values ​​of the two motion states, and the purpose is to adapt to the situation after the motion state changes, the value of the work W done by the human body is fixed to the work W done by the human body after the motion state changes, rather than before or limited to between the two, but the human metabolic rate M is continuously changing, not just for the values ​​of the two motion states, so the metabolic rate M needs to be limited to the minimum and maximum values ​​of the two motion states; and then the temperature and wind speed of the air conditioner in the cabin are adjusted according to the predicted temperature t' and the predicted air flow rate v', but the predicted human metabolic rate, i.e., M0 and M1, is based on the amount of exercise, which is different from the actual human metabolic rate, so it is necessary to detect the actual human metabolic rate M after the subject's motion state changes, and at this time the gas volume V in the cabin for calculating the actual human metabolic rate has already changed. If a change occurs, the function of the air volume V in the cabin with respect to the temperature t and the air flow rate v is obtained through machine learning or two-dimensional fitting in the "pre-correction of metabolic data", and then the existing metabolic data is corrected to obtain the precise value of the human metabolic rate. Then, the precise value M1 of the human metabolic rate after the subject's motion state changes and the external work W1 in the current state are obtained through the metabolic cabin system. The predicted temperature t' and the predicted air flow rate v' are substituted into the PMV index calculation model to update the PMV index value. At this time, when the PMV index value is between the thresholds, it means that the adjustment is successful and the adjustment is ended. When the PMV index value is not between the thresholds, there are two situations. One is caused by the prediction of the metabolic rate, and the other is that the metabolic rate value is too large or the external work is too large to find a PMV index value that meets the threshold, so a larger adjustment of the environment is required. The adjustment method is as follows:

[0124] After obtaining the precise value M1 of the human metabolic rate after the subject's motion state changes and the human body's external work W1 as input, the PMV index calculation model established is used to solve the extreme value of |PMV|, obtain the extreme temperature t″ and the extreme air flow rate v″, and finally adjust the temperature and wind speed of the air conditioner in the cabin according to the extreme temperature t″ and the extreme air flow rate v″. Among them, |PMV| represents the absolute value of the PMV index calculation model. Because the highest comfort is a practical requirement after establishing the |PMV| model, the extreme value solved is the most comfortable index in the current environment. When solving the extreme value of the |PMV| model, there are only two variables, temperature t and air flow rate v. Therefore, the gradient matrix can be solved by the Newton optimal method of multi-dimensional variables, and the extreme value condition of the |PMV| model is when the gradient is 0.

[0125] Example 1

[0126] Measurement of resting metabolic rate (RMR) can be used to monitor a subject's basic physical condition (whether they have a fever, infection, etc.), for scientific weight loss and thyroid function testing. The strictest definition of BMR requires that an individual be in a post-absorptive state (10-12 hours without consuming high-calorie food or beverages), while the body is undisturbed, awake, and in a thermoneutral environment. However, a single metabolic chamber system cannot meet the subject's requirements. Not only for the sake of subject comfort, the difference in resting metabolic rate between subjects of different genders can reach 30%, and the thermoneutral environment is different for different subjects. Therefore, the system of the present invention can be used to measure resting metabolic rate (RMR), including the following steps:

[0127] Step A100, calculate the PMV index using the PMV index calculation model, which includes the following parameters: temperature t, air flow rate v, human metabolic rate M, human external work W, radiation temperature t r , relative humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl The specific model is established with temperature t, air velocity v, human metabolic rate M and human external work W as variables, and the radiation temperature t r , humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl PMV index calculation model is a constant;

[0128] Step A200, first detect the initial environmental variables t0, v0, which are the cabin temperature and air flow rate obtained at this time, and the gas volume V in this state and the data measured by the metabolic chamber system (F, ) Calculate the exact value M2 of the human metabolic rate, substitute it into the established PMV index calculation model to calculate the current PMV index value. If it is not within the threshold, the predicted temperature t′ and predicted air flow rate v′ are obtained through the nonlinear programming equation (the human metabolic rate M in the nonlinear programming equation is between 0 and M2). Adjust the temperature and wind speed of the air conditioner in the cabin according to the predicted temperature t′ and the predicted air flow rate v′. Because the changes to the entire system are small this time, there is no need to make secondary modifications during the measurement of the resting metabolic rate (RMR), so that the subjects can keep the measured value in a thermoneutral environment. Then, through machine learning or two-dimensional fitting in the "pre-correction of metabolic data", the function of the air volume V in the cabin with respect to temperature t and air flow rate v is obtained, and the existing metabolic data is corrected to obtain an accurate resting metabolic rate measurement value.

[0129] Example 2

[0130] EE measurement related to physical activity is used to evaluate the aerobic and anaerobic exercise capacity of the subjects. However, different metabolic rates and external work under different exercise states will inevitably cause changes in the environment in the cabin. It is also necessary to measure the metabolic rate of the exercise state in a thermoneutral environment. Based on this reference Figure 2 As shown in the figure, the changes in metabolic rate under different exercise states. The top curve in the figure shows the changes in metabolic rate under high exercise frequency (Gear-8), the middle curve shows the changes in metabolic rate under low exercise frequency (Gear-4), and the bottom curve shows the changes in metabolic rate under non-exercise state. It can be seen that the changes in metabolic rate under a single exercise state are divided into three stages: metabolic rate rise period, recovery period, and stable period. To maintain the same comfort index conditions in the stable period, metabolic rate rise period, and recovery period, different environments are inevitably required. Therefore, the system of the present invention can be used for EE measurement related to physical activity, specifically including the following:

[0131] Step B100, calculate the PMV index using the PMV index calculation model, the PMV index calculation model includes the following parameters: temperature t, air flow rate v, human metabolic rate M, human external work W, radiation temperature t r , relative humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl The specific model is established with temperature t, air velocity v, human metabolic rate M and human external work W as variables, and the radiation temperature t r , humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl PMV index calculation model is a constant;

[0132] Step B200, calculating a predicted value M' of the human metabolic rate M: when the subject's physical activity changes and enters a non-thermoneutral state, the predicted value M' of the human metabolic rate M is calculated based on the subject's exercise state;

[0133] Step B300, pre-adjustment of temperature and air flow rate: When the subject's physical activity changes, the initial parameters in the metabolic chamber are first obtained. Then, based on the change in the subject's motion state, the body's external work W1 and the predicted value M1' of the body's metabolic rate M are determined. After inputting the PMV index calculation model from step B100, the nonlinear programming equation is solved to obtain the predicted temperature t' and predicted air flow rate v', which are used to adjust the temperature and wind speed of the air conditioning system.

[0134] Step B400, pre-conditioning the air conditioning system and calculating the pre-conditioning PMV index: adjust the temperature and wind speed of the air conditioning system in the metabolic chamber according to the predicted temperature t' and predicted air flow rate v' obtained in step B300; after the metabolic chamber system stabilizes, first obtain the human metabolic rate M1 after the change in the subject's motion state through the metabolic chamber system, then input the human body external work W1 determined based on the change in the subject's motion state, as well as the human metabolic rate M1, the predicted temperature t', and the predicted air flow rate v', into the PMV index calculation model to determine the pre-conditioning PMV index value P1;

[0135] Step B500, checking the pre-conditioning result: comparing the pre-conditioning PMV index value P1 determined in step B400 with the set threshold value P to determine whether the subject is in a thermoneutral state. If the subject is in a thermoneutral state, the adjustment is terminated and the human metabolic rate M is measured under the predicted temperature t' and predicted air velocity v'. If the subject is not in a thermoneutral state, the process proceeds to step B600.

[0136] Step B600, extreme value adjustment of the air-conditioning system: input the human metabolic rate M1 and the external work done by the human body W1 obtained in step B400 into the PMV index calculation model to solve the extreme value of |PMV|, obtain the extreme temperature t″ and the extreme air flow rate v″, adjust the temperature and wind speed of the air-conditioning system in the cabin according to the extreme temperature t″ and the extreme air flow rate v″, and measure the human metabolic rate M under the extreme temperature t″ and the extreme air flow rate v″ environment.

[0137] Example 3

[0138] Submaximal exercise testing (GXT) is a multi-stage submaximal exercise test used to estimate VO2max. The standard GXT test, combined with metabolic analysis during the test, has been evaluated as a clinical standard test for patients with CHF undergoing transplant surgery and individuals with unexplained exertional dyspnea. Figure 3 As shown, the figure shows the oxygen consumption of a single stage of exercise. Figure 3The oxygen consumption plateau in the late exercise state is maintained constant during this plateau, and the maximum oxygen uptake is the maximum plateau that can be reached during exercise. Based on this, for the different load increases (every 2-3 minutes) in the multi-level submaximal exercise test, it is required that each plateau enter a thermoneutral state. Therefore, the system of the present invention can be used to measure gas exchange and ventilatory response in submaximal exercise testing (GXT), which specifically includes the following steps:

[0139] Step C100, PMV index calculation, the PMV index calculation model includes the following parameters: temperature t, air flow rate v, human metabolic rate M, human external work W, radiation temperature t r , relative humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl The specific model is established with temperature t, air velocity v, human metabolic rate M and human external work W as variables, and the radiation temperature t r , humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl PMV index calculation model is a constant;

[0140] Step C200, calculating a predicted value M' of the human metabolic rate M: when the subject's physical activity changes and enters a non-thermoneutral state, the predicted value M' of the human metabolic rate M is calculated based on the subject's exercise state;

[0141] Step C300, pre-adjustment of temperature and air flow rate: When the subject's physical activity changes, the initial parameters of the metabolic chamber are first obtained. Then, based on the change in the subject's motion state, the body's external work W1 and the predicted value M1' of the body's metabolic rate M are determined. After inputting the PMV index calculation model from step C100, the nonlinear programming equation is solved to obtain the predicted temperature t' and predicted air flow rate v', which are used to adjust the temperature and wind speed of the air conditioning system.

[0142] Step C400, pre-conditioning the air conditioning system and calculating the pre-conditioning PMV index: the temperature and wind speed of the air conditioning system in the metabolic chamber are adjusted according to the predicted temperature t' and predicted air flow rate v' obtained in step S300; after the metabolic chamber system stabilizes, the human metabolic rate M1 after the change in the subject's motion state is first obtained through the metabolic chamber system, and then the human body external work W1 determined based on the change in the subject's motion state, as well as the human metabolic rate M1, the predicted temperature t', and the predicted air flow rate v' are input into the PMV index calculation model to determine the pre-conditioning PMV index value P1;

[0143] Step C500, detecting the pre-conditioning result: comparing the pre-conditioning PMV index value P1 determined in step C400 with the set threshold value P to determine whether the subject is in a thermoneutral state. If the subject is in a thermoneutral state, the adjustment is terminated and the human metabolic rate M is measured under the predicted temperature t' and predicted air velocity v'. If the subject is not in a thermoneutral state, the process proceeds to step SC00;

[0144] Step C600, extreme value adjustment of the air conditioning system: The human metabolic rate M1 and the human external work W1 obtained in step C400 are input into the PMV index calculation model to obtain the extreme value of |PMV|, and the extreme temperature t″ and the extreme air flow rate v″ are obtained. The temperature and wind speed of the cabin air conditioning system are adjusted according to the extreme temperature t″ and the extreme air flow rate v″, and the human metabolic rate M is measured under the extreme temperature t″ and the extreme air flow rate v″ environment;

[0145] Step C700, when entering or about to enter the second exercise load of the submaximal exercise test, re-determine the external work W2 and the predicted value of the human metabolic rate M2′, input the established PMV index calculation model, and solve the nonlinear programming equation to obtain the predicted temperature t′1 and the predicted air flow rate v′1; adjust the temperature and wind speed of the air conditioner in the cabin according to the predicted temperature t′1 and the predicted air flow rate v′1, obtain the precise value of the human metabolic rate M2, the predicted temperature t′1, and the predicted air flow rate v′1 for the second exercise load of the submaximal exercise test through the metabolic cabin system, input the PMV index calculation standard to determine the current PMV index value; and readjust the current PMV index value based on the comparison with the set threshold value;

[0146] Step C800, before entering the submaximal exercise test each time, re-enter a cycle of measurement and reset until the submaximal exercise test (GXT) is completed, and at the same time, "metabolic data pre-correction" is performed on the metabolic data of each stage.

[0147] The above embodiments are preferred implementation modes of the present invention and are only used to facilitate the explanation of the present invention. They are not intended to limit the present invention in any form. Any person with ordinary knowledge in the technical field can, without departing from the scope of the technical features of the present invention, make partial changes or modifications to the technical contents disclosed in the present invention and make equivalent embodiments without departing from the technical features of the present invention. Such modifications still fall within the scope of the technical features of the present invention.

Claims

1. A method for measuring human body data in a metabolic chamber based on comfort, characterized in that: The average thermal sensation index calculation model is introduced into the metabolic chamber system measurement to ensure that the subject is always in a thermoneutral state during metabolic data measurement, including the following steps: Step S100, calculate the average thermal sensation index using the average thermal sensation index calculation model, the average thermal sensation index calculation model includes the following parameters: temperature t, air flow rate v, human metabolic rate M, human external work W, radiation temperature t r , relative humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl , where the radiation temperature t r , Thermal resistance of clothing of subjects in the cabin I cl is a constant, relative humidity RH, temperature t, and air velocity v are obtained from the humidity sensor, temperature sensor, and wind speed probe in the metabolic chamber system, respectively. The human metabolic rate M is obtained in real time from the metabolic chamber system. The external work done by the human body W is determined based on the subject's exercise state. The calculated average thermal sensation index is combined with the set threshold P to determine whether the subject is in a thermoneutral state. Step S200, calculating a predicted value M' of the human metabolic rate M: when the subject's physical activity changes and enters a non-thermoneutral state, the predicted value M' of the human metabolic rate M is calculated based on the subject's exercise state; Step S300, pre-adjustment of temperature and air flow rate: When the subject's physical activity changes, first obtain the temperature t, air flow rate v, and radiation temperature t in the metabolic chamber at this time. r , Thermal resistance of clothing of subjects in the cabin I cl and relative humidity RH, then determine the human body's external work W1 and the predicted value M1' of the human metabolic rate M based on the change in the subject's motion state, input the average thermal sensation index calculation model of step S100, and solve the nonlinear programming equation to obtain the predicted temperature t' and the predicted air flow rate v'. The nonlinear programming equation includes an objective function and a satisfaction condition. The objective function is used to limit the change in temperature t and air flow rate v to a minimum. The satisfaction condition is used to ensure that the average thermal sensation index in the metabolic chamber is always within a set threshold P. The solved predicted temperature t' and predicted air flow rate v' are used to adjust the temperature and wind speed of the air conditioning system. Step S400, pre-conditioning the air conditioning system and calculating the average thermal sensation index after pre-conditioning: the temperature and wind speed of the air conditioning system in the metabolic chamber are adjusted according to the predicted temperature t' and predicted air flow rate v' obtained in step S300; after the metabolic chamber system stabilizes, the human metabolic rate M1 after the change in the subject's motion state is first obtained through the metabolic chamber system; then, the human body external work W1 determined based on the change in the subject's motion state, as well as the human metabolic rate M1, the predicted temperature t', and the predicted air flow rate v' are input into the average thermal sensation index calculation model to determine the average thermal sensation index value P1 after pre-conditioning; Step S500, detecting the pre-conditioning result: comparing the average thermal sensation index value P1 after pre-conditioning determined in step S400 with a set threshold value P to determine whether the subject is in a thermoneutral state. If the subject is in a thermoneutral state, the adjustment is terminated and the human metabolic rate M is measured under the predicted temperature t' and predicted air velocity v'. If the subject is not in a thermoneutral state, the process proceeds to step S600. Step S600, extreme value adjustment of the air-conditioning system: input the human metabolic rate M1 and the external work done by the human body W1 obtained in step S400 into the average thermal sensation index calculation model to solve the extreme value of |PMV|, obtain the extreme temperature t″ and the extreme air flow rate v″, adjust the temperature and wind speed of the air-conditioning system in the cabin according to the extreme temperature t″ and the extreme air flow rate v″, and measure the human metabolic rate M under the extreme temperature t″ and the extreme air flow rate v″ environment.

2. The method for measuring human body data in a metabolic chamber based on comfort level according to claim 1, characterized in that: The calculation model of the average thermal sensation index in step S100 is as follows: PMV=a*[(MW)-HE c -C res -E res ](a=0.303*e -0.306M +0.028) Where M is the metabolic rate of the human body, W is the work done by the human body, H is the sensitive heat loss of the human body, and E c is the heat exchange through evaporation on the skin, C res is the convective heat exchange of breathing, E res Exchanges heat for evaporation during breathing.

3. The method for measuring human body data in a metabolic chamber based on comfort level according to claim 2, characterized in that: The average thermal sensation index calculation model uses temperature t, air velocity v, human metabolic rate M, and human external work W as variables. The radiation temperature t r , humidity RH and the thermal resistance of the subjects' clothing in the cabin I cl The specific model establishment steps include: determining the human body sensitive heat loss function H = k1 (t, v, M, W) through temperature t, air flow rate v, human metabolic rate M and human external work W; determining the heat exchange function E generated by evaporation on the skin through temperature t, human metabolic rate M and human external work W. c = k2(t,M,W); Determine the convective heat transfer function C of breathing by temperature t and human metabolic rate M res = k3(t,M); Determine the evaporative heat exchange function E of respiration by temperature t and human metabolic rate M res =k4(t,M), and then the average thermal sensation index calculation model is obtained: PMV=k(t,v,M,W)=a*[(MW)-k1(t,v,M,W)-k2(t,M,W)-k3(t,M)-k4(t,M)].

4. The method for measuring human body data in a metabolic chamber based on comfort level according to claim 1, characterized in that: The metabolic cabin system includes a cabin, a mass flow controller, a gas analyzer and a pressure differential sensor; the cabin is sealed to provide a countercurrent air flow into the cabin, and air is extracted from the cabin at the other end to form an outflow air flow. The mass flow controller detects the flow rate of the countercurrent air flow, the gas analyzer detects the concentration of carbon dioxide and oxygen in the outflow air flow, and the pressure differential sensor is used to balance the air pressure inside and outside the cabin.

5. The method for measuring human body data in a metabolic chamber based on comfort level according to claim 4, characterized in that: The human metabolic rate M is obtained in real time from the measurement of the metabolic chamber system, which means that the human metabolic rate M is determined by the quotient of the energy consumption rate MR and the body surface area BSA; energy consumption MR = 3.941*VO2 + 1.106*VCO2, where VO2 is the oxygen metabolic consumption rate and VCO2 is the carbon dioxide metabolic production rate; VO2 and VCO2 are determined by the following formula: Where F is the counterflow air flow into the cabin, which is set by the mass flow controller and is the gas flow under standard conditions. are the concentrations of oxygen and carbon dioxide entering and flowing out of the metabolic compartment, respectively. To pre-set concentration, The concentrations of oxygen and carbon dioxide in the outflowing air stream are detected by a gas analyzer; is the time variation of the concentration of oxygen and carbon dioxide in the air in the metabolic chamber; V is the volume of air in the standard state under the metabolic chamber environment at this time; N is the Haldane coefficient.

6. The method for measuring human body data in a metabolic chamber based on comfort level according to claim 5, characterized in that: The air volume V in the metabolic chamber at different temperatures t and air flow rates v is determined by a gas washout test, which includes the following steps: Step T100 , first obtaining the temperature t and air flow rate v in the cabin, and then injecting a certain amount of carbon dioxide into the cabin so that the concentration levels of oxygen and carbon dioxide in the cabin are different from those of fresh air; Step T200: Fresh air is continuously introduced into the cabin via a mass flow controller, and the concentration of oxygen or carbon dioxide flowing out of the cabin is continuously monitored via a gas analyzer; the difference between the concentration of the oxygen or carbon dioxide flowing out of the cabin and the concentration of the corresponding gas in the fresh air decreases as the monitoring duration continues, until the concentration of the oxygen or carbon dioxide flowing out of the cabin is consistent with the concentration in the fresh air. Step T300 , inverting the cabin air volume V by collecting the flow rate of fresh air flowing into the cabin and the concentration of oxygen or carbon dioxide flowing out of the cabin to solve the zero-input differential equation.

7. The method for measuring human body data in a metabolic chamber based on comfort level according to claim 6, characterized in that: In step T300, the zero-input differential equation is: in, is the concentration of carbon dioxide flowing out of the cabin, measured by a gas analyzer, F is the flow rate of fresh air flowing into the cabin, set by a mass flow controller, which is the gas flow rate under standard conditions, A and C are fitting indices, V is the air volume in the cabin under standard conditions at a certain temperature t and a certain air flow rate v, and t is the time constant; in order to obtain the air volume V in the cabin at different temperatures t and air flow rates v, multiple groups of samples including temperature t, air flow rate v and corresponding cabin air volume V are obtained through multiple gas flushing tests, and the function of cabin air volume V with respect to temperature t and air flow rate v is obtained through machine learning or two-dimensional fitting.

8. The method for measuring human body data in a metabolic chamber based on comfort level according to claim 1, characterized in that: In step S200, the external work W1 of the human body and the predicted value M1′ of the human metabolic rate are determined according to the subject's exercise state, including the external work W determined by the change of the mechanical energy of the human body's center of gravity based on kinematic considerations and the change of the predicted value M′ of the human metabolic rate M based on the amount of exercise. The nonlinear programming equation in step S200 is: Among them, t0 and v0 are the temperature t and air flow rate v in the metabolic chamber obtained in step 300, W1 is the work W done by the human body determined according to the subject's exercise state in step S300, M0 and M1 are the minimum and maximum values ​​of the change in the predicted value M′ of the metabolic rate M based on the amount of exercise; solving the nonlinear programming equation is to solve the predicted temperature t′ and predicted air flow rate v′ that meet the conditions, among which the initial values ​​of x and y are X0=t0 and Y0=v0.

9. A measurement system for implementing the metabolic chamber human body data measurement method based on comfort as described in any one of claims 1 to 8, characterized in that: include: A data acquisition system for obtaining parameters required for calculating the average thermal sensation index in the cabin; An average thermal sensation index data processing system is used to establish an average thermal sensation index calculation model according to the average thermal sensation index calculation standard and determine the temperature and air flow rate according to the nonlinear programming equation; a metabolic data processing system for determining a value of an air volume V according to the temperature and the air flow rate, and calculating an energy consumption rate MR according to the updated value of the air volume V; The control module is used to adjust the temperature and wind speed of the cabin air conditioning system according to the temperature and air flow rate.

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