Adaptive feedback simulation device and method for local active sweating of the human body under low pressure environment

Abstract

This invention discloses an adaptive feedback simulation device and method for active localized sweating of the human body under low-pressure environments. It comprises a segmental human body model shell, a temperature acquisition device, a temperature control device, an adaptive feedback prediction module for temperature and sweating rate, and a sweating control device. The adaptive feedback prediction module for temperature and sweating rate has been modified for low-pressure environments. The prediction module exchanges data in real time with the temperature acquisition device, temperature control device, and sweating control device to achieve accurate simulation of the skin temperature and sweating rate of the segmental human body model shell under low-pressure environments. The features and beneficial effects of this invention are: it simulates the changes in sweat secretion rate caused by the human nervous system regulating sweat gland activity under low-pressure environments through active sweating; it can simulate the local skin temperature field of the human body's thermoregulation system under an adaptive feedback mechanism in low-pressure environments, with temperature distribution and sweating rate more closely resembling real physiological states. It can be applied to ergonomic research of protective clothing for human bodies in low-pressure environments such as aviation and high-altitude areas.

Description

Technical Field

[0001] This invention relates to ergonomic research on heat transfer between the human body, clothing, and environment in aviation or high-altitude environments, specifically to an adaptive feedback simulation device and method for active local sweating of the human body in low-pressure environments. Background Technology

[0002] Traditional human local sweating simulation devices mostly rely on passive sweating methods, which involve wetting the simulated skin on the outside of the outer shell to saturate the simulated skin with water. The amount of local sweating is calculated by measuring the amount of water evaporation from the simulated skin surface over a certain period of time.

[0003] Existing passive sweating simulation methods can only simulate the physical process of water evaporation and cannot simulate the changes in sweat secretion rate caused by the human nervous system regulating sweat gland activity under low pressure. The intensity of human sweat gland activity is related to local skin temperature. Changes in the skin temperature field under low pressure will affect the rate of sweat secretion, thus affecting the measured amount of sweat. Changes in the measured amount of sweat will also affect the skin temperature measurement results by altering the amount of heat dissipated through evaporation. Existing active sweating simulation methods do not consider the impact of skin temperature changes on sweat secretion rate under low pressure and are therefore unsuitable for simulating the physiological phenomena of human thermoregulation under low pressure, resulting in inaccurate simulation results for local skin temperature, metabolic rate, and sweat volume.

[0004] Therefore, in order to solve the problems existing in the prior art, this application combines an adaptive feedback algorithm for low-pressure environments to dynamically control the sweating rate based on changes in the local skin temperature field of the human body, thereby improving the simulation accuracy of the human body's thermophysiological response under special low-pressure environments. Summary of the Invention

[0005] The purpose of this invention is to provide an adaptive feedback simulation device and method for active local sweating of the human body under low-pressure environments, thereby solving the problems of existing passive sweating simulation methods mentioned in the background section. To achieve the above objective, the technical solution of this invention is as follows:

[0006] An adaptive feedback simulation device for localized active sweating in the human body under low pressure includes:

[0007] The system comprises a human segmental model shell, a temperature acquisition device, a temperature control device, a sweating control device, and a host computer. The human segmental model shell is shaped to mimic the geometry and dimensions of a human forearm and is divided into four temperature zones (top, bottom, left, and right). Each temperature zone has a 2mm diameter sweating hole. The temperature acquisition device, temperature control device, and sweating control device are installed inside the human segmental model shell and connected to and communicate with the host computer. The temperature acquisition device collects the temperature of each temperature zone and transmits it to the host computer. The host computer controls the operation of the heating film in the temperature control device to control the human segmental model shell to reach the target temperature. The sweating control device controls simulated sweat to actively transport to the sweating holes of the human segmental model shell at a target sweating rate. The host computer also has a temperature and sweating rate adaptive feedback prediction module, which calculates the target temperature and target sweating rate based on the temperature values ​​collected by the temperature acquisition device and environmental parameters.

[0008] The sweating control device includes an injection pump 6, a power supply 7, a silicone tube 8, a one-to-four splitter 9, and a constant temperature water tank 10. The host computer controls the injection pump to draw simulated sweat from the constant temperature water tank and then, at a certain rate, inputs the simulated sweat into the inlet of the one-to-four splitter through the silicone tube. The simulated sweat then flows from the four outlets of the one-to-four splitter through the silicone tube to the sweat pores, thereby accurately and quantitatively delivering the simulated sweat to the outer surface of the human body segment model shell, simulating the sweat gland secretion process of the human body.

[0009] The temperature acquisition device includes 12 PT100 temperature sensors, which are fixed and acquire the temperature at the center, inner and outer sides of each temperature zone.

[0010] The syringe pump has a Y-type valve. The inlet and outlet of the Y-type valve are connected to the constant temperature water tank and the inlet of the 1-to-4 splitter respectively through silicone tubes. The host computer controls the opening direction of the Y-type valve through a motor, thereby switching the working state of the syringe pump for water suction and injection. The host computer controls the inlet suction rate or outlet flow rate by controlling the linear velocity of the piston pusher. The water temperature in the constant temperature water tank is 35℃.

[0011] The control process of the temperature and sweating rate adaptive feedback prediction module is as follows: the human body is simplified into 16 segments: head, chest, back, pelvis, left shoulder, right shoulder, left arm, right arm, left hand, right hand, left thigh, right thigh, left calf, right calf, left foot, and right foot. Each segment is divided into four temperature nodes according to the core layer, muscle layer, fat layer, and skin layer. The temperature in each tissue layer is considered uniform. The temperature control equation is:

[0012] Core layer:

[0013]

[0014] Muscle layer and fat layer:

[0015]

[0016] Skin layer:

[0017]

[0018] In equations (1)-(3), C represents the volumetric specific heat capacity of the human tissue corresponding to each temperature node in the 16 segments, T represents the temperature value of each temperature node in the 16 segments, t represents time, Q represents the sum of internal metabolism, work done to the outside, and heat generated by shivering, B represents the heat carried away from each temperature node by blood convection heat transfer, and D represents the heat conducted from the temperature node to its adjacent temperature node on the outside. in RES represents the heat conducted from adjacent inner temperature nodes towards that temperature node, RES represents the heat dissipated by the thoracic segment core layer to the external environment through respiration, and Q represents the heat loss from respiration. t E represents the dry state of heat dissipation from the skin layer to the external environment through convection and radiation, while E represents the wet state of heat dissipation from the skin layer to the external environment due to the evaporation of sweat from the body surface.

[0019] Among them, Q t The convective heat transfer component Q in c Calculated according to Newton's law of cooling:

[0020] Q c =h c (Tt a A (4)

[0021] In equation (4), h c The convective heat transfer coefficient between human skin and the environment is represented by T, which represents the temperature of 16 skin segments, and t. a The ambient temperature is represented by A, and the skin surface area of ​​the 16 segments is represented by h. c Calculated using the following formula (5):

[0022]

[0023] The evaporative heat transfer coefficient involved in the wet heat dissipation E is calculated using the following formula (6):

[0024]

[0025] In equations (5)-(6), h c This represents the convective heat transfer coefficient (W / (m)). 2 ·℃), h c0 =4.4W / (m 2 ·℃), Pb Indicates ambient air pressure (kPa), h e The evaporative heat transfer coefficient (W / (m)) represents the evaporative heat transfer coefficient. 2 ·kPa), LR0 represents the Lewis proportionality constant (16.7℃ / kPa). According to Newton's law of cooling, the convective heat transfer between the human body and the environment under different ambient air pressures can be calculated using equation (5); the skin temperature and ambient temperature in Newton's law of cooling are replaced by the saturated vapor pressure of water on the skin surface and the partial pressure of water vapor in the environment, and the heat dissipation due to sweat evaporation on the human skin surface under different ambient air pressures can be calculated using equation (6).

[0026] The temperature and sweating rate adaptive feedback prediction module solves the above control equations (1)-(3) based on the initial values ​​of the temperature field of each temperature node in each segment of the human body under a specific external environment, as well as the environmental temperature, humidity, and air pressure parameters, to predict the whole-body skin temperature field and obtain the target skin temperature of the forearm; based on the average skin temperature of the forearm measured by the temperature acquisition device, the target sweating rate is calculated using the temperature-sweating rate coupled prediction model:

[0027] m ASW =0.00981×(0.15T) s -1.7) (7)

[0028] In equation (7), m ASW The T represents the rate of sweating of the forearm skin (g / s). s This indicates the average skin temperature of the forearm (°C).

[0029] This application also provides an adaptive feedback simulation method for localized active sweating of the human body under low-pressure conditions, which uses the aforementioned adaptive feedback simulation device for localized active sweating of the human body under low-pressure conditions and includes the following process:

[0030] S1: Obtain the input parameters of the temperature and sweating rate adaptive feedback prediction module. The ambient temperature, ambient humidity, and ambient air pressure are determined by the temperature, humidity, and air pressure of the experimental environment. Here, the initial value of the temperature field of each segment of the human body is taken as the temperature of each segment of the human body obtained by experimental measurement.

[0031] S2: The temperature control device adjusts the average temperature of the shell of the human local segment model to near the initial value of the human forearm skin temperature, and judges whether the average temperature of the shell of the human local segment model has reached stability; it is stable near the initial value of the human forearm skin temperature, that is, the error between the average temperature of the shell of the human local segment model and the initial value of the human forearm skin temperature is no greater than 0.1℃.

[0032] S3: If the average temperature of the human body segment model shell has not reached stability, repeat step S2; if the average temperature of the human body segment model shell has reached stability, the target temperature of the human body segment model shell is calculated through iterative solution by the temperature and sweating rate adaptive feedback prediction module; based on the calculated target temperature, the host computer controls the temperature control device to adjust the average temperature of the human body segment model shell to near the target temperature through the temperature control algorithm, and stabilizes it near the target temperature, that is, the error between the average temperature of the human body segment model shell and the target temperature is no greater than 0.1℃; the actual temperature of the human body segment model shell measured by the temperature acquisition device updates the initial value of the human forearm skin temperature.

[0033] S4: The temperature and sweating rate adaptive feedback prediction module calculates the sweating rate of the forearm skin based on the actual temperature of the human body segment model shell measured by the temperature acquisition device at the current moment. The host computer controls the sweating control device to make the sweating rate of the sweat pores on the surface of the human body segment model shell the calculated value.

[0034] The adaptive feedback simulation device and method for active local sweating in low-pressure environments provided by this invention can simulate the active control of skin temperature and sweating rate by the human nervous system under different environmental pressure conditions, realizing the dynamic process simulation of skin temperature and sweating. By taking into account the feedback effect of skin temperature and sweating rate under low-pressure conditions, it more accurately simulates the regulation of real physiological body temperature under special conditions. It has been verified that it can well simulate the body temperature regulation process of the human body under long-term low-pressure conditions, and has good consistency with the temperature curve and sweating state measured in experiments. It solves the problems of existing human local sweating simulation devices where the amount of sweat secretion cannot be autonomously controlled and the skin temperature simulation effect under low-pressure conditions is inaccurate. Attached Figure Description

[0035] The working principle and beneficial effects of the present invention will be more readily apparent from the description of the embodiments in conjunction with the following accompanying drawings, wherein:

[0036] Figure 1 Schematic diagram of the connection and control relationship of an adaptive feedback simulation device for active local sweating of the human body under low pressure environment.

[0037] Figure 2 This is a schematic diagram of a 1-to-4 splitter structure. The left image is a cross-sectional view, and the right image is a structural schematic diagram.

[0038] Figure 3 This is a schematic diagram of the structure and connection of the injection pump in the sweat control device.

[0039] Figure 4 Workflow diagram of an adaptive feedback simulation device for localized active sweating in the human body under low pressure environment

[0040] Explanation of reference numerals in the attached diagram: 1. Outer shell of human body segment model; 2. PT100 temperature sensor; 3. Temperature acquisition module; 4. Heating film; 5. SCR temperature controller; 6. Injection pump; 7. Power supply; 8. Silicone capillary tube; 9. One-to-four splitter; 10. Constant temperature water tank; 11. Host computer; 12. Y-type valve; 13. Valve motor; 14. Syringe; 15. Piston pusher; 16. Piston fastening screw; 17. Piston drive motor. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Figure 1 This is a schematic diagram of an adaptive feedback simulation device for active localized sweating of the human body under low pressure. The device includes a segmental human body model shell 1, a temperature acquisition device, a temperature control device, a sweating control device, and a host computer 11. The temperature acquisition device, temperature control device, and sweating control device are installed inside the segmental human body model shell 1. The temperature acquisition device collects the surface temperature of the segmental human body model shell 1. The temperature control device heats and controls the surface temperature of the segmental human body model shell 1 to reach a target temperature. The sweating control device simulates sweating to regulate the temperature of the segmental human body model shell 1. The host computer 11 is connected to the temperature acquisition device, temperature control device, and sweating control device, transmits commands, collects and records temperature data from the temperature acquisition device, and sends control signals to control the operation of the temperature control device. The host computer 11 also has an adaptive feedback prediction module for temperature and sweating rate, used to control the operation of the temperature control device and sweating control device under low pressure, thereby controlling the temperature and sweating rate of the segmental human body model shell 1.

[0043] The outer shell 1 of the human segment model is an arc-shaped curved shell that simulates the geometry of the human forearm. It consists of two halves of the shell, which are connected by detachable methods such as screws and clips. It can be formed by 3D printing of aluminum alloy. The two halves of the shell are divided into four temperature zones in the vertical direction, and each zone has a sweat pore with a diameter of 2mm.

[0044] The temperature acquisition device includes 12 PT100 temperature sensors 2 and a temperature acquisition module 3. The 12 PT100 temperature sensors 2 are distributed at the center and near the edge of the inner side of the human body segment model shell 1. The acquired temperature signals are converted into electrical signals by the temperature acquisition module 3 and then uploaded to the host computer 11 via a data cable. Specifically, the 12 PT100 temperature sensors 2 in the temperature acquisition device are attached and fixed to the inner wall of the human body segment model shell 1 with thermally conductive silicone. One PT100 temperature sensor 2 is fixed at the center, and one is fixed at the inner and outer sides of each temperature zone, that is, each temperature zone has 3 temperature measurement points. The 12 PT100 temperature sensors 2 are electrically connected to the 12 input channels of the temperature acquisition module 3. The output signal of the temperature acquisition module 3 can be converted from RS485 to RS232 by an RS232 data cable, and then sampled by the temperature acquisition program of the host computer 11 at a sampling rate of 1Hz. The host computer synchronously stores the sampling time and the measured values ​​of the 12 PT100 temperature sensors 2 in a text document.

[0045] The temperature control device includes heating films 4 and a silicon controlled rectifier (SCR) temperature controller 5. Four heating films 4 are fixed to four temperature zones on the inner wall of the human body segment model shell 1 using thermally conductive silicone. The difference between the average temperature of the four temperature zones (the average temperature of two temperature measuring points on the inner and outer sides of each temperature zone) and the target temperature is input to the host computer. The output voltage of the SCR temperature controller 5 and the power of the heating films 4 are adjusted in real time. A PID control algorithm can be used for the control process. The average temperature on the inner and outer sides of the shell is indirectly controlled by the temperature at the center of each temperature zone, resulting in a more stable and accurate temperature control effect.

[0046] The sweating control device includes an injection pump 6, a power supply 7, silicone tubes 8, a one-to-four splitter 9, and a constant temperature water tank 10. The ends of the four silicone tubes 8 are fitted with locking cones and then fixed with silicone glue to the four sweating holes in the four temperature zones of the outer shell 1 of the human body segment model. The other ends are fixed with locking cones to the one-to-four splitter 9. Figure 2The device is a 1-to-4 flow divider 9, which evenly divides the fluid entering from one inlet into four channels for outflow. Preferably, the 1-to-4 flow divider 9 is cubic in shape, with circular holes at the center of the top and four sides. These holes are interconnected at the center of the inside of the 1-to-4 flow divider 9. The top hole is the inlet, and the four side holes are the outlets. Simulated sweat enters through the central hole at the top of the 1-to-4 flow divider 9, flows through four horizontally oriented cross-shaped pipes, and then flows out from the four side walls of the 1-to-4 flow divider 9. It then passes through four silicone tubes 8 and finally flows out from the sweat pores on the surface of the human body segment model shell 1. The inlet and outlet of the syringe pump are connected to the constant temperature water tank and the inlet of the 1-to-4 flow divider, respectively. The syringe pump is used to draw simulated sweat from the constant temperature water tank and control the flow of simulated sweat into the inlet of the 1-to-4 flow divider 9 at a certain rate, thereby controlling the sweating rate on the surface of the human body segment model shell 1. Specifically, the syringe pump device can be an MSP-CX1 model syringe pump. The constant temperature water tank 10 controls the water temperature at 35℃ to simulate the change in body surface temperature during sweat secretion, which is the actual temperature of the human body.

[0047] Taking the MSP-CX1 model syringe pump as an example, Figure 3 This is a structural diagram of the syringe pump 6 in the sweating control device. The inlet of the one-to-four flow divider 9 is connected to the outlet of the syringe pump's Y-type valve 12 via a silicone tube 8 and a locking cone. When the syringe pump 6 is running, the valve motor 13 controls the opening direction of the Y-type valve 12, thereby switching the working state of the syringe pump 6 from water intake to injection. The syringe 14 and the piston pusher 15 are connected by a piston fixing screw 16. The host computer 11 controls the rotational speed of the piston drive motor 17 according to the linear velocity compilation instructions of the piston pusher 15 in the syringe 14, thereby adjusting the vertical movement linear velocity of the piston pusher 15 and controlling the flow rate of water intake at the inlet and water output at the outlet of the syringe pump 6, thus realizing continuous sweating and autonomous continuous control of the sweating rate. The inlet of the syringe pump's Y-type valve 12 is connected to the constant temperature water tank 10 via a silicone tube 8 and a locking cone. The syringe pump 6 is powered by the power supply 7 and can communicate with the host computer 11 via an RS485 to RS232 converter and an RS232 data cable.

[0048] Figure 4 This is a flowchart illustrating the workflow of an adaptive feedback simulation device for localized active sweating in the human body under low-pressure conditions. The specific steps are as follows:

[0049] S1: Obtain the input parameters of the temperature and sweating rate adaptive feedback prediction module. The ambient temperature, ambient humidity, and ambient air pressure are determined by the temperature, humidity, and air pressure of the experimental environment. Here, the initial value of the temperature field of each segment of the human body is taken as the temperature of each segment of the human body obtained by experimental measurement.

[0050] S2: The temperature control device adjusts the average temperature of the shell of the human local segment model to near the initial value of the human forearm skin temperature, and judges whether the average temperature of the shell of the human local segment model has reached stability; it is stable near the initial value of the human forearm skin temperature, that is, the error between the average temperature of the shell of the human local segment model and the initial value of the human forearm skin temperature is no greater than 0.1℃.

[0051] S3: If the average temperature of the human body segment model shell has not reached stability, repeat step S2; if the average temperature of the human body segment model shell has reached stability, the target temperature of the human body segment model shell is calculated through iterative solution by the temperature and sweating rate adaptive feedback prediction module; based on the calculated target temperature, the host computer controls the temperature control device to adjust the average temperature of the human body segment model shell to near the target temperature through the temperature control algorithm, and stabilizes it near the target temperature, that is, the error between the average temperature of the human body segment model shell and the target temperature is no greater than 0.1℃; the actual temperature of the human body segment model shell measured by the temperature acquisition device updates the initial value of the human forearm skin temperature.

[0052] S4: The temperature and sweating rate adaptive feedback prediction module calculates the sweating rate of the forearm skin based on the actual temperature of the human body segment model shell measured by the temperature acquisition device at the current moment. The host computer controls the sweating control device to make the sweating rate of the sweat pores on the surface of the human body segment model shell the calculated value.

[0053] The implementation process of the control method for the temperature and sweating rate adaptive feedback prediction module is as follows: The human body is simplified into 16 segments: head, chest, back, pelvis, left shoulder, right shoulder, left arm, right arm, left hand, right hand, left thigh, right thigh, left calf, right calf, left foot, and right foot. Each segment is divided into four temperature nodes according to the core layer, muscle layer, fat layer, and skin layer. The temperature in each tissue layer is considered uniform. The internal heat transfer process of the human body is simplified into a one-dimensional heat transfer problem radially along the four temperature nodes of each segment. Based on the energy balance relationship of each temperature node, the control equation for temperature is given in the form of differential equations:

[0054] Core layer:

[0055]

[0056] Muscle layer and fat layer:

[0057]

[0058] Skin layer:

[0059]

[0060] In equations (1)-(3), C represents the volumetric specific heat capacity of the human tissue corresponding to each temperature node in the 16 segments, T represents the temperature value of each temperature node in the 16 segments, t represents time, Q represents the sum of internal metabolism, work done to the outside, and heat generated by shivering, B represents the heat carried away from each temperature node by blood convection heat transfer, and D represents the heat conducted from the temperature node to its adjacent temperature node on the outside. in RES represents the heat conducted from adjacent inner temperature nodes towards that temperature node, RES represents the heat dissipated by the thoracic segment core layer to the external environment through respiration, and Q represents the heat loss from respiration. t E represents the dry state of heat dissipation from the skin layer to the external environment through convection and radiation, while E represents the wet state of heat dissipation from the skin layer to the external environment due to the evaporation of sweat from the body surface.

[0061] Among them, Q t The convective heat transfer component Q in c Calculated according to Newton's law of cooling:

[0062] Q c =h c (Tt a A (4)

[0063] In equation (4), h c The convective heat transfer coefficient between human skin and the environment is represented by T, which represents the temperature of 16 skin segments, and t. a The ambient temperature is represented by A, and the skin surface area of ​​the 16 segments is represented by h. c Calculated using the following formula (5):

[0064]

[0065] The evaporative heat transfer coefficient involved in the wet heat dissipation E is calculated using the following formula (6):

[0066]

[0067] In equations (5)-(6), h c This represents the convective heat transfer coefficient (W / (m)). 2 ·℃), h c0 =4.4W / (m 2 ·℃), P b Indicates ambient air pressure (kPa), h e The evaporative heat transfer coefficient (W / (m)) represents the evaporative heat transfer coefficient. 2·kPa), LR0 represents the Lewis proportionality constant (16.7℃ / kPa). According to Newton's law of cooling, the convective heat transfer between the human body and the environment under different ambient air pressures can be calculated using equation (5); the skin temperature and ambient temperature in Newton's law of cooling are replaced by the saturated vapor pressure of water on the skin surface and the partial pressure of water vapor in the environment, and the heat dissipation due to sweat evaporation on the human skin surface under different ambient air pressures can be calculated using equation (6).

[0068] The temperature and sweating rate adaptive feedback prediction module solves the above control equations (1)-(3) based on the initial values ​​of the temperature field of each temperature node in each segment of the human body under a specific external environment, as well as the environmental temperature, humidity, and air pressure parameters, to predict the whole-body skin temperature field and obtain the target skin temperature of the forearm; based on the average skin temperature of the forearm measured by the temperature acquisition device, the target sweating rate is calculated using the temperature-sweating rate coupled prediction model:

[0069] m ASW =0.00981×(0.15T) s -1.7) (7)

[0070] In equation (7), m ASW The T represents the rate of sweating of the forearm skin (g / s). s This indicates the average skin temperature of the forearm (°C).

[0071] Specifically, the temperature and sweating rate adaptive feedback prediction module controls the sweating rate on the surface of the human body segment model shell 1 using the following method: After calculating the target sweating rate, the host computer first controls the syringe piston via the piston drive motor 17 to fill the silicone tube 8 of the sweating control device with water. Then, based on the calibration curve between the sweating rate and the syringe piston linear velocity, the sweating rate is converted into the linear velocity of the syringe piston of the injection pump. The host computer 11 then compiles communication instructions and inputs them into the injection pump 6, causing the injection pump 6 to continuously cycle and perform water absorption and injection actions according to the given sweating rate, thus simulating active sweating in a localized area of ​​the human body. The water source for the sweating control system comes from a constant temperature water tank 10, which maintains the water temperature at 35℃ to simulate the temperature change of the body surface during sweat secretion at a real human body temperature. Furthermore, the temperature and sweating rate adaptive feedback prediction module updates the initial value of the whole-body skin temperature field based on the temperature value collected by the temperature acquisition device, and continues to iteratively predict the temperature field. The host computer continues to control the temperature and sweating rate based on the calculation results.

[0072] Traditional human localized sweating simulation devices mostly rely on passive sweating methods, where simulated skin on the outside of the outer shell is saturated with water. The amount of localized sweating is calculated by measuring the amount of water evaporation from the simulated skin surface over a certain period. Passive sweating simulation methods can only simulate the physical process of water evaporation and cannot simulate the changes in sweat secretion rate caused by the human nervous system regulating sweat gland activity under low pressure. The intensity of human sweat gland activity is related to local skin temperature. Changes in the skin temperature field under low pressure will affect the sweat secretion rate, thus affecting the measured sweat volume. Changes in the measured sweat volume will also affect the skin temperature measurement results by altering the amount of heat dissipated through evaporation. Therefore, this application provides an adaptive feedback algorithm suitable for low-pressure environments that dynamically controls the sweating rate based on changes in the local skin temperature field, improving the simulation accuracy of the human body's thermophysiological response under special low-pressure environments.

[0073] Compared with traditional human body local sweating simulation devices that utilize passive sweating methods, the beneficial effects of this invention are: (1) By using a sweating control device, active sweating is achieved through sweating pores on the surface of the human body local segment model shell, which can actively adjust the sweat secretion rate and simulate the change in sweat secretion rate caused by the human nervous system regulating sweat gland activity under low pressure; (2) The proposed temperature and sweating rate adaptive feedback prediction module can simulate the change in heat exchange between the human body and the external environment under low pressure, and dynamically control the sweating rate according to the change in the local skin temperature field of the human body, thereby improving the simulation accuracy of the human body's thermophysiological response under low pressure special environment.

[0074] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An adaptive feedback simulation device for localized active sweating of the human body under low-pressure conditions, characterized in that, include: The system comprises a human segment model shell, a temperature acquisition device, a temperature control device, a sweating control device, and a host computer. The shape of the human body segment model shell simulates the geometry and size of the human forearm. The human body segment model shell is divided into four temperature zones: top, bottom, left, and right. Each temperature zone has a sweat pore with a diameter of 2mm. The temperature acquisition device, the temperature control device, and the sweating control device are installed inside the shell of the human body segment model and are connected to and communicate with the host computer. The temperature acquisition device is used to collect the temperature of each temperature zone and transmit it to the host computer; the temperature acquisition device includes 12 PT100 temperature sensors, which are fixed and collect the temperature at the center, inner and outer sides of each temperature zone respectively. The host computer controls the operation of the heating film in the temperature control device to control the shell of the human body segment model to reach the target temperature. The sweating control device can control simulated sweat to actively transport at a target sweating rate to the sweating pores on the shell of the human body segment model. The sweating control device includes an injection pump, a silicone tube, a one-to-four splitter, and a constant-temperature water tank. The host computer, based on the target sweating rate calculated by the temperature and sweating rate adaptive feedback prediction module, controls the injection pump to draw simulated sweat from the constant-temperature water tank and then, at the target sweating rate, inputs the simulated sweat into the inlet of the one-to-four splitter through the silicone tube. The simulated sweat then flows out from the four outlets of the one-to-four splitter... A silicone tube transports the simulated sweat to the sweat pores, precisely and quantitatively delivering the simulated sweat to the outer surface of the human body segment model, simulating the sweat gland secretion process in the human body. The injection pump has a Y-type valve, the inlet and outlet of which are connected to a constant temperature water tank and a one-to-four splitter inlet, respectively, via silicone tubes. The host computer controls the opening direction of the Y-type valve via a motor, switching the injection pump's suction and injection modes. The host computer controls the inlet suction rate or outlet flow rate by controlling the linear velocity of the piston pusher. The water temperature in the constant temperature water tank is 35°C. The host computer also has a temperature and sweating rate adaptive feedback prediction module, and the target temperature and target sweating rate are calculated by the temperature and sweating rate adaptive feedback prediction module based on the temperature value and environmental parameters collected by the temperature acquisition device. The process by which the temperature and sweating rate adaptive feedback prediction module calculates the target temperature is as follows: The human body is simplified into 16 segments: head, chest, back, pelvis, left shoulder, right shoulder, left arm, right arm, left hand, right hand, left thigh, right thigh, left calf, right calf, left foot, and right foot. Each segment is further divided into four temperature nodes based on the core layer, muscle layer, fat layer, and skin layer. The temperature within each tissue layer is considered uniform, and the temperature control equation is: Core layer: (1) Muscle layer and fat layer: (2) Skin layer: (3) Where C represents the volumetric specific heat capacity of human tissue corresponding to each temperature node in the 16 segments, T represents the temperature value of each temperature node in the 16 segments, t represents time, Q represents the sum of internal metabolism, work done to the outside world, and heat production from shivering, B represents the heat carried away from each temperature node by blood convection, D represents the heat conducted from that temperature node to its adjacent temperature node, RES represents the heat dissipation from the core layer of the thoracic segment to the external environment through respiration, and D in Q represents the heat conducted from the inner adjacent temperature node towards this temperature node. t E represents the dry state of heat dissipation from the skin layer to the external environment through convection and radiation, while E represents the wet state of heat dissipation from the skin layer to the external environment due to the evaporation of sweat from the body surface. Among them, Q t The convective heat transfer component Q in c Calculated according to Newton's law of cooling: (4) In equation (4), h c The convective heat transfer coefficient between human skin and the environment is represented by T, which represents the temperature of 16 skin segments, and t. a The ambient temperature is represented by A, and the skin surface area of ​​the 16 segments is represented by h. c Calculated using the following formula (5): (5) Among them, h c0 = 4.4 W / (m 2 ·℃), P b Indicates ambient air pressure (kPa); The evaporative heat transfer coefficient involved in the wet heat dissipation E is calculated using the following formula (6): (6) Where h e The evaporative heat transfer coefficient (W / (m)) represents the evaporative heat transfer coefficient. 2 ·kPa), LR0 represents the Lewis proportionality constant, taken as 16.7℃ / kPa; The temperature and sweating rate adaptive feedback prediction module solves the above control equations (1)-(3) based on the initial values ​​of the temperature field of each segment of the human body under a specific external environment, environmental temperature, humidity and air pressure parameters, to predict the whole body skin temperature field and obtain the target forearm skin temperature; then, it extracts the predicted value of the forearm skin temperature from the whole body skin temperature field at each moment, and calculates the target sweating rate using the temperature-sweating rate coupled prediction model: (7) Where m ASW The target sweat rate of the forearm skin (g / s), T s This indicates the average skin temperature of the forearm (°C).

2. An adaptive feedback simulation method for localized active sweating of the human body under low pressure, employing the adaptive feedback simulation device for localized active sweating of the human body under low pressure as described in claim 1, comprising the following processes: S1: Obtain the input parameters of the temperature and sweating rate adaptive feedback prediction module. The ambient temperature, ambient humidity, and ambient air pressure are determined by the temperature, humidity, and air pressure of the experimental environment. Here, the initial value of the temperature field of each segment of the human body is taken as the temperature of each segment of the human body obtained by experimental measurement. S2: The temperature control device adjusts the average temperature of the shell of the human local segment model to near the initial value of the human forearm skin temperature, and judges whether the average temperature of the shell of the human local segment model has reached a stable value. S3: If the average temperature of the human body segment model shell has not reached stability, repeat step S2; if the average temperature of the human body segment model shell has reached stability, the target temperature of the human body segment model shell is calculated through iterative solution by the temperature and sweating rate adaptive feedback prediction module; based on the calculated target temperature, the host computer controls the temperature control device through the temperature control algorithm to adjust the average temperature of the human body segment model shell to reach and stabilize near the target temperature, that is, the error between the average temperature of the human body segment model shell and the target temperature is no greater than 0.1℃; the actual temperature of the human body segment model shell measured by the temperature acquisition device updates the initial value of the human forearm skin temperature; S4: The temperature and sweating rate adaptive feedback prediction module calculates the target sweating rate of the forearm skin based on the actual temperature of the human body segment model shell measured by the temperature acquisition device at the current moment. The host computer controls the sweating control device to make the simulated sweat flow out of the sweat pores at the target sweating rate.

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