Lower limb pressurization control method of intelligent compression stocking

Abstract

The application discloses a lower limb pressurization control method of intelligent pressure socks, and relates to the technical field of medical pressure auxiliary devices and physiological parameter detection control; the method comprises the following steps: collecting body posture sensing data, lower limb volume change data, lower limb hemodynamic data and equipment pressure feedback data in real time, identifying a current posture state and a current activity state, setting a posture switching flag, judging whether the lower limb volume change data and the lower limb hemodynamic data are reliable, generating edema judgment results and venous return judgment results when the data are reliable, determining target pressurization intensity and target pressurization rhythm according to the judgment results, and executing real-time adjustment in combination with the equipment pressure feedback data; the application can improve the pressurization control stability and the venous return auxiliary reliability of the intelligent pressure socks in different postures and posture switching processes.

Description

Technical Field

[0001] This invention relates to the field of medical pressure assistive devices and physiological parameter detection and control technology, and more specifically, to a method for controlling lower limb pressure with intelligent pressure socks. Background Technology

[0002] With the development of wearable medical devices and home rehabilitation equipment, assistive devices such as medical compression stockings, elastic compression stockings, and lower limb compression aids are increasingly being used in scenarios such as lower limb venous return obstruction, edema management, lower limb support for people who sit or stand for long periods, and postoperative rehabilitation care. These devices typically apply external pressure to areas such as the calf and ankle through airbags, elastic fabrics, or controllable pressure structures to assist venous blood return to the heart and reduce tissue fluid pooling. Simultaneously, physiological parameter detection technologies are also being incorporated into wearable devices. For example, inertial sensors are used for body posture detection, bioimpedance sensors or flexible circumference sensors are used to detect changes in lower limb volume, photoplethysmography (PPG), optical blood flow sensors, or ultrasonic sensors are used to collect lower limb hemodynamic data, and pressure sensors are used to obtain device pressure feedback data, thus providing a monitoring basis for lower limb compression control.

[0003] While existing smart compression stockings or lower limb compression devices can achieve fixed pressure application, graded pressure application, or simple periodic inflation and deflation, their control logic typically relies more on preset levels, manual mode selection, or single pressure feedback results. They fail to adequately differentiate the impact of different postures and activity states, such as lying down, sitting, standing, walking, and climbing stairs, on lower limb venous return and edema trends. In actual use, frequent changes in body posture alter the venous load and tissue compression state in the lower limbs. If the compression intensity and rhythm from the previous state are maintained, insufficient support is likely after standing, or pressure release is delayed after sitting or lying down, resulting in discontinuous venous return assistance, localized discomfort, or delayed pressure control.

[0004] Furthermore, lower limb volume change data and lower limb hemodynamic data are inherently susceptible to motion artifacts, sensor adhesion, relative skin slippage, and local tissue deformation. Current technologies often directly use instantaneous detection values ​​for pressure regulation during dynamic activity, or only perform closed-loop correction on pressure sensor results, without first determining the reliability of lower limb volume change data and lower limb hemodynamic data under the current activity state. Therefore, during walking, running, or posture changes, short-term fluctuations in sensor signals may be misinterpreted as increased edema or impaired venous return, triggering unnecessary pressure enhancement or rhythm alterations.

[0005] Furthermore, in existing compression stocking control systems, there is a lack of clear linkage between baseline compression intensity, baseline compression rhythm, and edema and venous return assessment results. The pressure feedback data from the device is often only used to determine whether the set pressure has been reached, without incorporating postural transitions to smoothly control pressure rises, falls, and rhythmic transitions. This makes the compression device prone to sudden pressure increases and decreases, frequent control jitter, or abrupt changes in inflation / deflation rhythm when the target pressure changes, affecting the safety, comfort, and continuous support effectiveness of lower limb compression aids.

[0006] Therefore, how to combine physiological parameter detection results and the pressure execution characteristics of lower limb compression aids during the lower limb compression control process of smart compression stockings, and uniformly constrain body posture, activity state, lower limb volume changes, lower limb hemodynamic state, and equipment pressure feedback, in order to avoid control errors caused by posture switching, unreliable signals, and pressure closed-loop lag, has become a technical problem that needs to be solved. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this application aims to provide a method for controlling lower limb compression with intelligent compression stockings. This method involves real-time acquisition of body posture sensing data, lower limb volume change data, lower limb hemodynamic data, and device pressure feedback data to identify the current posture and activity state. By combining posture switching indicators, edema assessment results, and venous return assessment results, the target compression intensity and rhythm are determined. The compression intensity and rhythm are then adjusted in real-time based on the device pressure feedback data. This solves the problem that existing medical compression stockings, lower limb compression aids, and lower limb venous return aids are difficult to coordinate with changes in posture, physiological state, and pressure application status during use. It also addresses the difficulty of directly converting existing physiological parameter detection and lower limb hemodynamic monitoring results into closed-loop pressure control data, achieving dynamic, continuous, and safe control of the lower limb compression process during different postures and posture switching.

[0008] To achieve the above objectives, this application adopts the following technical solution:

[0009] In a first aspect, this application provides a method for controlling lower limb compression with smart compression stockings, characterized in that it includes:

[0010] Real-time acquisition of body posture sensing data, lower limb volume change data, lower limb hemodynamic data, and equipment pressure feedback data;

[0011] Based on body posture sensing data, the current posture state and current activity state are identified;

[0012] Compare the current attitude state with the attitude state at the previous moment to determine whether an attitude transition has occurred, and set an attitude transition flag.

[0013] Based on the current activity status, determine whether the lower limb volume change data and lower limb hemodynamic data are reliable; if the lower limb volume change data and lower limb hemodynamic data are reliable, then the edema judgment result is obtained based on the lower limb volume change data, and the venous return judgment result is obtained based on the lower limb hemodynamic data.

[0014] Based on the current posture, the corresponding baseline compression intensity and baseline compression rhythm are set, and based on the edema assessment results and venous return assessment results, the baseline compression intensity and baseline compression rhythm are adjusted to obtain the target compression intensity and target compression rhythm.

[0015] Pressure control is performed based on attitude switching indicators, target pressurization intensity, and target pressurization rhythm, and the pressurization intensity and rhythm are adjusted in real time based on equipment pressure feedback data.

[0016] Preferably, the current posture includes lying down, sitting, and standing; the current activity includes lying still, sitting still, standing still, walking slowly, walking normally, walking quickly, going up and down stairs, and running.

[0017] Preferably, the contact state of the sensor is determined based on the DC component of the optical signal, the pulsating component of the optical signal, and the impedance or circumference sampling stability of the lower limb hemodynamic data;

[0018] If the current activity state is slow walking, normal walking, fast walking, going up and down stairs, or running, it is determined to be in the dynamic data collection stage, and the lower limb hemodynamic data and lower limb volume change data are marked as unreliable;

[0019] If the current activity state is in a lying, sitting, or standing position, the static data acquisition phase begins, and the sensor contact status is determined. If the sensor contact status is determined to be good, the lower limb hemodynamic data and lower limb volume change data are marked as reliable.

[0020] Preferably, the maximum allowable pressure, the minimum effective pressure corresponding to each posture state, and the interval duration adjustment step are preset;

[0021] The pressure adjustment step is set based on the maximum allowable pressure and the minimum effective pressure corresponding to the current attitude state.

[0022] If the edema assessment result is increased edema and the venous return assessment result is poor venous return, then increase the baseline compression intensity by the first number of pressure adjustment steps and decrease the interval duration of the baseline compression rhythm by the first number of interval duration adjustment steps.

[0023] If only one of the edema assessment results is increased edema or only one of the venous return assessment results is poor venous return, then the basal compression intensity is increased by a second number of pressure adjustment steps, and the interval duration of the basal compression rhythm is decreased by a second number of interval duration adjustment steps.

[0024] If the edema assessment result is non-increased edema and the venous return assessment result is normal venous return, then the baseline compression intensity is reduced by the second number of pressure adjustment steps, but must not be lower than the minimum effective pressure corresponding to the current posture state, and the interval duration of the baseline compression rhythm is increased by the second number of interval duration adjustment steps.

[0025] Both the first quantity and the second quantity are preset positive integers, and the first quantity is greater than the second quantity; the first quantity and the second quantity are predetermined based on the maximum allowable pressure, the minimum effective pressure corresponding to the current attitude state, and the setting result of the pressure adjustment step; the target pressurization intensity does not exceed the maximum allowable pressure.

[0026] Preferably, the maximum pressure increase increment per second and the maximum pressure decrease increment per second are set based on the maximum allowable pressure; the current actual pressure is obtained by performing a sliding mean filter on the equipment pressure feedback data in each control cycle; the pressure error is obtained by subtracting the current actual pressure from the target pressurization intensity.

[0027] A pre-defined mapping table between pressure change rate and actuator control quantity is prepared. The mapping table uses the current actual pressure as an index to provide the pressure change per unit time under different combinations of air pump drive duty cycle, air valve opening degree, and air valve opening degree.

[0028] Preferably, when the attitude switching flag is true and the target pressure intensity is higher than the current actual pressure, the pressure is increased by combining the coarse adjustment stage and the fine adjustment stage.

[0029] Preferably, in the coarse adjustment stage, the pressure error entering the coarse adjustment stage is recorded as the initial pressure error, and the expected pressure increment for the current control cycle is calculated based on the current pressure error, the maximum pressure increase per second, and the control cycle; according to the pressure change rate and actuator control quantity mapping table, the air pump drive duty cycle and air valve opening that match the expected pressure increment are selected, and the exhaust valve opening is set to 0; when the current pressure error decreases to below the preset proportion of the initial pressure error, the fine adjustment stage is entered.

[0030] Preferably, in the fine-tuning stage, proportional-integral closed-loop control is used to control the pressurization intensity. The proportional coefficient and integral coefficient in the proportional-integral closed-loop control are obtained through pressure step response calibration. The control quantity increment in the proportional-integral closed-loop control is mapped to the increment of the air pump drive duty cycle, and the air pump drive duty cycle is limited to between 0 and 1.

[0031] Preferably, when the attitude switching flag is true and the target pressurization intensity is lower than the current actual pressure, the currently used pressurization rhythm is updated to the target pressurization rhythm within a preset delay confirmation time.

[0032] After the delayed confirmation time ends, the expected pressure reduction for this control cycle is calculated based on the pressure error, and the opening of the exhaust valve is increased according to the pressure change rate and actuator control quantity mapping table based on the expected pressure reduction.

[0033] When the pressure change rate and actuator control quantity mapping table shows that the exhaust valve opening has reached the maximum available opening in the current actual pressure range and is still insufficient to provide the desired pressure reduction, the air pump drive duty cycle is reduced to 0, the air charging valve opening is set to 0, and the preset low-resistance exhaust passage or reverse pressure relief passage is opened to supplement the desired pressure reduction.

[0034] Preferably, when the attitude switching flag is false, and the target pressurization intensity and target pressurization rhythm change relative to the target pressurization intensity and target pressurization rhythm of the previous control cycle, the pressure dead zone threshold is set based on the pressure regulation step.

[0035] If the absolute value of the pressure error does not exceed the pressure dead zone threshold, the pressure control command remains unchanged.

[0036] If the absolute value of the pressure error exceeds the pressure dead zone threshold, a slope threshold is set based on the maximum pressure increase per second and the maximum pressure decrease per second. The expected pressure increment or expected pressure decrease for each control cycle is calculated according to the slope threshold. Then, the air pump drive duty cycle, air valve opening, and exhaust valve opening are updated through the pressure change rate and actuator control quantity mapping table.

[0037] Compared with the prior art, the beneficial effects achieved by this application are as follows:

[0038] This application reconstructs the relatively fixed pressure output process in existing lower limb compression devices such as medical compression stockings, elastic compression stockings, and lower limb compression aids into a closed-loop control process composed of posture recognition, physiological state judgment, target compression parameter generation, and pressure feedback execution by jointly processing body posture sensing data, lower limb volume change data, lower limb hemodynamic data, and device pressure feedback data. This enables smart compression stockings to determine the target compression intensity and target compression rhythm based on the current posture, current activity state, edema judgment results, and venous return judgment results, thereby reducing the problems of insufficient pressure, excessive pressure, or rhythm mismatch that are prone to occur with fixed compression methods under different postures.

[0039] This application determines the reliability of lower limb volume change data and lower limb hemodynamic data based on the current activity state. It can incorporate physiological parameter detection, lower limb hemodynamic monitoring, lower limb volume change monitoring, and sensor contact status judgment into the same control basis screening process. This prevents data affected by motion artifacts, sensor slippage, or poor contact from directly triggering changes in pressure intensity and pressure rhythm, thereby reducing the risk of falsely triggering pressure adjustments and improving the input reliability of edema judgment results and venous return judgment results when participating in control decisions.

[0040] This application sets the baseline compression intensity and rhythm based on the current posture state, and adjusts them in conjunction with edema assessment results and venous return assessment results. This allows the lower limb compression control results to simultaneously reflect postural load differences, lower limb volume change trends, and venous return status. Compared to methods that adjust based on a single pressure level, single posture, or single physiological signal, this application provides a clearer basis for generating the target compression intensity and target compression rhythm, and reduces control deviations caused by the disconnect between different assessment results.

[0041] This application implements pressure control based on posture switching indicators, target pressure intensity, and target pressure rhythm, and adjusts the pressure intensity and rhythm in real time according to equipment pressure feedback data. This enables a closed-loop correspondence between the target pressure parameters and the actual pressure output state of the smart pressure sock. By utilizing the response relationships between pressure error, pressure change rate, actuator control quantity mapping table, air pump drive duty cycle, inflation valve opening, and deflation valve opening, this application can more stably convert the target pressure intensity into the actual pressure applied to the lower limb surface, reducing the accumulation of control deviations caused by differences in equipment air paths, changes in airbag compliance, or pressure sensor noise.

[0042] This application distinguishes between two control processes—increased target pressure and decreased target pressure—when the posture switching flag is true. It employs a combination of coarse and fine adjustment, as well as delayed confirmation and controlled pressure relief, to balance support establishment speed and pressure change smoothness during posture switching. This avoids sudden pressure increases, decreases, or rhythm changes when users switch between lying, sitting, and standing positions, thereby improving the continuity and safety of the lower limb venous return assistance process.

[0043] In summary, this application does not simply increase the number of sensors or change the pressure level, but rather focuses on the lower limb compression control process of smart compression stockings. It coordinates the pressure execution process of medical compression stockings and lower limb compression aids with body posture detection, lower limb volume change detection, lower limb hemodynamic monitoring, and device pressure feedback detection results. This allows physiological state recognition results to be continuously transmitted to the target compression parameter generation and pressure execution feedback stages, thereby improving the accuracy, stability, consistency, and controllability of lower limb compression control. It is more suitable for continuous use in compression aid scenarios such as lower limb edema control, venous return assistance, and wearable compression devices. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of a lower limb compression control method for a smart compression sock according to an embodiment of the present invention;

[0045] Figure 2 This is a flowchart illustrating a method for adjusting the base pressurization intensity and base pressurization rhythm according to an embodiment of the present invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be described in detail, clearly, and completely below with reference to the accompanying drawings. It should be particularly noted that the specific embodiments described below are only for better illustrating and explaining the technical solutions of the present invention, and are intended to enable those skilled in the art to better understand and implement the present invention, and should not be construed as limiting the scope of protection of the present invention. Without departing from the spirit and substance of the present invention, those skilled in the art can modify, adjust, or make equivalent substitutions based on the content disclosed in the present invention, and these should all be considered within the scope of protection of the present invention.

[0047] Example 1:

[0048] Please see Figure 1 As shown, this embodiment provides a method for controlling lower limb compression with smart compression stockings, including:

[0049] The system collects body posture sensing data, lower limb volume change data, lower limb hemodynamic data, and device pressure feedback data in real time. Based on the body posture sensing data, it identifies the current posture state and current activity state. It compares the current posture state with the previous posture state to determine if a posture change has occurred and sets a posture change flag. Based on the current activity state, it assesses the reliability of the lower limb volume change data and lower limb hemodynamic data. If the lower limb volume change data and lower limb hemodynamic data are reliable, it determines the edema assessment result based on the lower limb volume change data and the venous return assessment result based on the lower limb hemodynamic data. Based on the current posture state, it sets the corresponding baseline pressure intensity and rhythm, and adjusts the baseline pressure intensity and rhythm based on the edema assessment result and the venous return assessment result to obtain the target pressure intensity and target rhythm. It executes pressure control based on the posture change flag, target pressure intensity, and target rhythm, and adjusts the pressure intensity and rhythm in real time based on the device pressure feedback data.

[0050] The system collects real-time body posture sensing data, lower limb volume change data, lower limb hemodynamic data, and equipment pressure feedback data, including:

[0051] The system synchronously reads the current values ​​of each sensor, including body posture sensing data obtained from the inertial sensor, lower limb volume change data obtained from the impedance or circumference sensor, lower limb hemodynamic data obtained from the optical blood flow sensor, and equipment pressure feedback data obtained from the pressure sensor.

[0052] Body posture sensing data is obtained by using inertial sensors such as accelerometers and gyroscopes worn on the lower limbs or other parts of the body to acquire human posture and motion information. For example, the sensors measure the acceleration and angular velocity of the body along each axis, and calculate the posture angle of the body relative to the direction of gravity to identify posture states such as standing, sitting, and lying down, as well as the range and rate of change of movement.

[0053] Lower limb volume change data are obtained by measuring subtle changes in lower limb volume or circumference using bioimpedance sensors or flexible circumference sensors to reflect the accumulation of tissue fluid and the degree of edema in the legs. A typical method is to attach electrodes to specific locations on the lower leg and measure the changes in tissue impedance under low current. Decreased impedance usually indicates an increase in lower limb volume, which may indicate a tendency for edema.

[0054] Lower limb hemodynamic data are obtained using optical sensors such as photoplethysmography (PPG) sensors or ultrasound sensors to acquire local blood flow parameters in the lower limbs. For example, PPG waveforms are collected at the ankle or calf to obtain venous filling, pulse amplitude, or blood oxygen levels to assess venous return. Lower limb hemodynamic data can reflect the efficiency of local blood perfusion and return in a resting state.

[0055] The device pressure feedback data is obtained by measuring the actual pressure applied to the lower limb surface in real time through pressure sensors installed in compression devices such as airbag protective gear or smart compression socks. The device pressure feedback data is used for feedback control to ensure that the applied pressure is consistent with the target value and to prevent overpressure or underpressure.

[0056] Based on body posture sensing data, the current posture state and current activity state are identified, including:

[0057] During the recognition process, the acceleration and angular velocity output by the inertial sensor are used to construct gravity direction and motion intensity indices. The gravity direction index is used to distinguish between lying, sitting, and standing postures, while the motion intensity index is used to distinguish between lying still, sitting still, standing still, slow walking, normal walking, fast walking, climbing stairs, and running. The current posture state is limited to lying, sitting, and standing, and the current activity state is limited to lying still, sitting still, standing still, slow walking, normal walking, fast walking, climbing stairs, and running.

[0058] The specific methods for identifying the current posture and current activity state are as follows: First, the triaxial acceleration in the body posture sensing data is low-pass filtered to extract the approximate gravity component. The angle between this gravity component and the sensor reference axis is then calculated to obtain a verticality index. The current posture state is determined by comparing the verticality index with two angle thresholds. The logic for setting the angle thresholds is as follows: after the device is first worn, 10 sets of calibration data are collected for both lying and standing still postures. The mean verticality index corresponding to the lying still calibration data, the mean verticality index corresponding to the standing still calibration data, and the mean verticality index corresponding to the lying still calibration data are calculated respectively. The dispersion of the verticality index and the dispersion of the verticality index corresponding to the standing static calibration data are used. The midpoint between the mean of the verticality index corresponding to the lying static calibration data and the mean of the verticality index corresponding to the standing static calibration data is used as the attitude boundary threshold. The larger value between the dispersion of the verticality index corresponding to the lying static calibration data and the dispersion of the verticality index corresponding to the standing static calibration data is determined as the safety margin. Two angle thresholds are formed by adding safety margins on both sides of the attitude boundary threshold, so that the current attitude state has a transition judgment range near the attitude boundary threshold, reducing the repeated changes in the current attitude state caused by short-term fluctuations in the verticality index.

[0059] When the verticality index is within the threshold range closer to the lying position, it is determined to be a lying position; when the verticality index is within the threshold range closer to the standing position, it is determined to be a standing position; and when the verticality index is between the two thresholds, it is determined to be a sitting position. This ensures that the posture classification remains consistent under different body types and different wearing angles.

[0060] After obtaining the current posture state, the current activity state is further identified; the triaxial acceleration and triaxial angular velocity in the body posture sensing data are bandpass processed, the acceleration energy and angular velocity energy within a fixed time window are calculated, and the two are weighted and summed to obtain the motion intensity index.

[0061] The threshold setting logic for the exercise intensity index is as follows: Ten sets of calibration data are collected for each of three static states: lying still, sitting still, and standing still. The mean and dispersion of the exercise intensity index are calculated. The maximum value of the mean exercise intensity index for each of the three static states plus three times the dispersion is used as the upper limit threshold for stillness. Next, calibration data for the exercise intensity index are collected for three walking states: slow walking, normal walking, and fast walking. The mean and dispersion of the slow walking calibration data, normal walking calibration data, and fast walking calibration data are calculated for each. The midpoint between the mean of the slow walking calibration data and the mean of the normal walking calibration data is used as the first grading benchmark value, and the midpoint between the mean of the normal walking calibration data and the mean of the fast walking calibration data is used as the second grading benchmark value. The maximum value among the dispersions of slow walking calibration data, normal walking calibration data, and fast walking calibration data is used as the walking safety margin. The walking safety margin is added to both sides of the first grading benchmark value to form the first grading threshold, and the walking safety margin is added to both sides of the second grading benchmark value to form the second grading threshold. When the exercise intensity index is higher than the static upper limit threshold but lower than the first grading threshold, the current activity state is judged as slow walking. When the exercise intensity index falls between the first grading threshold and the second grading threshold, the current activity state is judged as normal walking. When the exercise intensity index is higher than the second grading threshold, the current activity state is judged as a candidate state of fast walking, climbing stairs, or running, and enters the secondary differentiation process of angular velocity energy ratio and acceleration dominant frequency characteristics.

[0062] The distinction between going up and down stairs and running is triggered when the exercise intensity index exceeds the fast walking threshold, and a secondary distinction is made based on the angular velocity energy ratio and acceleration frequency characteristics. The acceleration frequency threshold, angular velocity energy ratio threshold, and peak-valley asymmetry threshold are all determined during the initial calibration phase based on the calibration mean and dispersion of the corresponding activity state. When the acceleration frequency is higher than the running frequency threshold and the exercise intensity index is higher than the running intensity threshold, it is judged as running. When the angular velocity energy ratio is higher than the stair-climbing angular velocity ratio threshold and the peak-valley asymmetry index is higher than the stair-climbing asymmetry threshold, it is judged as going up and down stairs. Other states that are higher than the second-level threshold but do not meet the running or stair-climbing conditions are judged as fast walking.

[0063] Finally, the current posture state and the motion intensity index judgment result are combined to output the current activity state, thus providing a consistent input basis for subsequent posture switching detection, signal reliability and trend evaluation, target pressure intensity and target pressure rhythm decision-making.

[0064] The current attitude state is compared with the attitude state at the previous moment to determine whether an attitude transition has occurred, and an attitude transition flag is set, specifically including:

[0065] The method for determining whether a pose change has occurred is as follows: At each recognition cycle, the current pose state is acquired, and the pose state of the previous moment and the previous stable pose state are saved. The previous stable pose state is used as a reference for pose change determination, avoiding repeated switching due to jitter within the pose critical range. If the current pose state is consistent with the previous stable pose state, the pose change flag is set to false, and the pose change timer value is cleared. If the current pose state is inconsistent with the previous stable pose state, the candidate pose change state is entered, the pose change timer value is accumulated over the recognition cycle, and the candidate pose state is continuously recorded.

[0066] To avoid misjudging brief movements, a time steady-state threshold is introduced as a switching confirmation condition. For example, the time steady-state threshold can be set to 2 seconds. The setting logic is to cover the transition segment of common short-term posture adjustment and brief pauses in standing up movements, so that the system only triggers the control strategy update when the posture change is continuous.

[0067] In the candidate switching state, if the current attitude state returns to the previous stable attitude state within the time steady-state threshold, the change is considered to be a temporary action. The attitude switching time value is cleared and the attitude switching flag is set to false, without triggering a policy change. If the current attitude state remains the same candidate attitude state for a continuous period of time that reaches or exceeds the time steady-state threshold, the attitude switching is confirmed to be valid. The attitude switching flag is set to true, the previous stable attitude state is updated to the candidate attitude state, and the attitude state at the previous moment is updated to the current attitude state for comparison in the next recognition cycle.

[0068] The attitude switching flag is set to true after the attitude switching is confirmed, and remains true until the current actual pressure enters the pressure dead zone threshold corresponding to the target pressurization intensity and the target pressurization rhythm is updated, after which it is reset to false.

[0069] Through the above mechanism, the attitude switching flag is set to true only when the attitude state undergoes a stable change, thus providing a clear and repeatable triggering condition for subsequent pressurization control execution and transition smoothing.

[0070] Based on the current activity state, determine the reliability of the lower limb volume change data and lower limb hemodynamic data; if the lower limb volume change data and lower limb hemodynamic data are reliable, then determine the edema assessment result based on the lower limb volume change data and the venous return assessment result based on the lower limb hemodynamic data, specifically including:

[0071] The current activity state is used to divide the acquisition phase into a static acquisition phase and a dynamic acquisition phase, so as to provide reliable constraints on signals that are susceptible to motion artifacts and avoid the control strategy being erroneously driven by transient fluctuations during attitude switching or dynamic activities.

[0072] First, the reliability of the signal is determined. If the current activity state is slow walking, normal walking, fast walking, going up and down stairs, or running, it is determined to be in the dynamic data acquisition stage.

[0073] During the dynamic acquisition phase, lower limb hemodynamic data and lower limb volume change data are prone to waveform distortion or baseline drift due to relative slippage between the skin and the sensor, local compression changes, tissue deformation, and vibration coupling. Therefore, the lower limb hemodynamic data and lower limb volume change data of the current cycle are marked as unreliable, and their instantaneous readings are prohibited from directly participating in the trend update and subsequent pressure detail adjustment of the current cycle. The latest valid trend results formed in the previous static acquisition phase are retained for subsequent transition smoothing.

[0074] If the current activity state is a lying, sitting, or standing still position, the system enters the static data acquisition phase. Further assessment of the sensor's contact status is then conducted to eliminate potential issues with poor contact that might arise from a static state alone. Good sensor contact is defined as meeting the following conditions simultaneously: within the most recent continuous sampling window, the DC component of the optical signal of the lower limb hemodynamic data is higher than the lower limit of the device's effective range and lower than the upper limit of the device's effective range; and the difference between the DC component of the optical signal of the lower limb hemodynamic data and the lower limit of the device's effective range is not less than a preset safety margin. The difference between the DC component of the optical signal of the lower limb hemodynamic data and the upper limit of the effective range of the device is not less than the preset safety margin, and the DC component of the optical signal of the lower limb hemodynamic data does not saturate or truncate; the effective amplitude of the pulsation component of the optical signal of the lower limb hemodynamic data is higher than the preset multiple of the calibration noise floor, and the difference between adjacent pulsation cycles does not exceed the calibration cycle dispersion threshold; the impedance or circumference sampling of the lower limb volume change data does not have a single sampling difference exceeding the calibration noise threshold in the most recent continuous sampling window, and the short-time variance of the lower limb volume change data is lower than the calibration noise threshold.

[0075] The setting logic for calibration noise threshold, calibration noise floor, preset multiplier, calibration period dispersion threshold, and preset safety margin is as follows: When wearing the device for the first time and in a supine or seated static position, collect static data for at least 30 seconds as a calibration window; calculate the median and dispersion index based on the lower limb volume change data within the calibration window, and multiply the dispersion index of the lower limb volume change data by a fixed safety factor to obtain the calibration noise threshold; based on the optical signal pulsation component of the lower limb hemodynamic data within the calibration window, extract the mean amplitude of the pulsation component and the noise dispersion, and determine the noise dispersion as the calibration noise floor. A preset multiple is determined based on the degree of separation between the average amplitude of the pulsation component and the calibration noise floor, so that the amplitude boundary corresponding to the preset multiple is higher than the noise fluctuation range and lower than the amplitude of the identifiable pulsation component within the calibration window; the period dispersion is calculated based on the difference between adjacent pulsation periods within the calibration window, and the period dispersion is multiplied by a fixed safety factor to serve as the calibration period dispersion threshold; a preset safety margin is determined based on the effective range width of the device, the sampling resolution, and the dispersion of the DC component of the optical signal within the calibration window, so that a sampleable margin is retained between the DC component of the optical signal and both the lower limit and the upper limit of the effective range of the device.

[0076] The method for setting the fixed safety factor is as follows: During the factory testing phase of the equipment, lower limb volume change data and lower limb hemodynamic data are collected under conditions of no pressure adjustment, no posture switching, and good sensor contact. The deviations of the lower limb volume change data from the median, the optical signal pulsation component from the median, the difference between adjacent pulsation cycles from the median, and the deviation of the optical signal DC component from the median are calculated. For each type of deviation, a fold coverage test is performed based on the corresponding dispersion index. The fold coverage test is performed sequentially according to the candidate folds arranged from low to high. The candidate folds are pre-stored in the equipment software. The lower limit of the candidate folds is not lower than the minimum resolvable fold corresponding to the sensor sampling resolution, and the upper limit of the candidate folds is not higher than the equipment's... The effective range allows for the determination of signal quality boundaries; when the dispersion boundary corresponding to a candidate multiple can cover all deviations in the corresponding deviation set, the candidate multiple is determined as the safety factor of the corresponding signal; after obtaining the safety factors for the lower limb volume change data, optical signal pulsation component, adjacent pulsation period difference, and optical signal DC component, the maximum value among the safety factors is determined as the fixed safety factor; during the initial wear calibration stage, the fixed safety factor is verified by the same multiple coverage test; when the safety factor obtained during the initial wear calibration stage is greater than the fixed safety factor obtained during the equipment factory test stage, the safety factor obtained during the initial wear calibration stage is updated to the fixed safety factor; when the safety factor obtained during the initial wear calibration stage is not greater than the fixed safety factor obtained during the equipment factory test stage, the fixed safety factor obtained during the equipment factory test stage remains unchanged.

[0077] If the above-mentioned good contact conditions are met during the static acquisition phase, the lower limb hemodynamic data and lower limb volume change data of this cycle will be marked as reliable and allowed to enter the trend assessment; otherwise, they will still be marked as unreliable and the previous valid trend results will be used.

[0078] Assuming the signal is reliable, further edema assessment is performed. First, a baseline level for lower limb volume change data is established within the calibration window, and the direction of change is clarified.

[0079] Since lower limb volume change data may come from either impedance or circumference acquisition methods, to ensure consistency of criteria, the lower limb volume change data is uniformly converted into a standardized sequence that monotonically corresponds to lower limb volume. During the calibration phase, the acquisition method identifier of the lower limb volume change data is read first. When the acquisition method identifier is impedance acquisition, the sign direction of the lower limb volume change data is set to the lower limb volume increase corresponding to a decrease in the original acquired value; when the acquisition method identifier is circumference acquisition, the sign direction of the lower limb volume change data is set to the lower limb volume increase corresponding to an increase in the original acquired value. When the acquisition method identifier cannot determine the sign direction of the lower limb volume change data, pressure disturbance calibration is performed during the static acquisition phase under good sensor contact conditions. The pressure disturbance value is determined by the pressure adjustment step and the current actual pressure. The pressure and maximum allowable pressure are jointly determined, the pressure disturbance value does not exceed the pressure adjustment step, and the pressure after the disturbance does not exceed the maximum allowable pressure. First, under the pressure before the disturbance, lower limb volume change data for one directional assessment window are collected, and the median of the lower limb volume change data within the directional assessment window is calculated as the representative value before the disturbance. Then, the current actual pressure is adjusted to the pressure after the disturbance. After the equipment pressure feedback data enters the allowable error range of the pressure after the disturbance, lower limb volume change data for the same duration are collected, and the median of the lower limb volume change data is calculated as the representative value after the disturbance. The duration of the directional assessment window is the same as the assessment cycle of the edema judgment result, and the allowable error range of the pressure after the disturbance is determined based on the pressure dead zone threshold. The difference between the representative value after the disturbance and the representative value before the disturbance is used to obtain the directional calibration difference value.

[0080] The dispersion of the lower limb volume change data within the calibration window is multiplied by a fixed safety factor to obtain the direction determination threshold. When the direction calibration difference is greater than the direction determination threshold, the sign direction of the lower limb volume change data is set to the increase in the original acquired value corresponding to an increase in lower limb volume. When the direction calibration difference is less than the negative of the direction determination threshold, the sign direction of the lower limb volume change data is set to the decrease in the original acquired value corresponding to an increase in lower limb volume. When the absolute value of the direction calibration difference is not greater than the direction determination threshold, no sign direction is generated for this pressure disturbance calibration, and the lower limb volume change data for this period is marked as unreliable. After determining the sign direction, the original acquired sequence is sign-transformed according to the sign direction so that an increase in the standardized lower limb volume change data value corresponds to an increase in lower limb volume.

[0081] After the direction is fixed, the moving average of the lower limb volume change data in the most recent fixed duration window is calculated as the current volume level in each assessment period. The relative change and the rate of change per unit time are calculated relative to the baseline. The rate of change per unit time is obtained by dividing the difference between the current volume levels of two adjacent assessment periods by the duration of the assessment period. It is used to characterize whether the volume change has a continuous upward trend rather than transient fluctuations.

[0082] The specific criteria for determining whether edema is increased or not include:

[0083] Set thresholds for edema assessment, rate of change assessment, and duration assessment.

[0084] The edema assessment threshold is jointly determined by a noise threshold and a minimum change threshold. The noise threshold is set to three times the dispersion of lower limb volume change data within the calibration window to cover measurement noise and natural fluctuations caused by slight body movement. The minimum change threshold is set to 0.02 of the baseline level to avoid responding to minute changes below the control response resolution. The edema assessment threshold is the larger of the noise threshold and the minimum change threshold, thus simultaneously achieving noise reduction and avoiding allergic reactions. The duration assessment threshold is set to 180 seconds, with the logic that the assessment of increased edema is based on cumulative changes over a continuous time scale, avoiding misinterpreting short-term transient fluctuations as cumulative edema.

[0085] The rate of change threshold is the ratio of the edema threshold to the duration threshold. This is used to constrain the volume increase to have a minimum sustained growth rate, thus preventing edema from being triggered by a single jump.

[0086] Edema is judged as increased if and only if the following conditions are met simultaneously: the deviation of the current volume level from the baseline level is not less than the edema judgment threshold, the rate of change per unit time is not less than the rate of change judgment threshold, and the above two conditions are maintained for a proportion of at least 0.8% within the assessment period covered by the most recent continuous judgment time threshold, thereby ensuring that the increase in edema corresponds to a trend inflection point of continuous rise rather than an isolated peak.

[0087] In cases other than increased edema, the edema assessment result is determined to be non-increased edema. This includes a stable state where the deviation is below the edema assessment threshold, and a declining state where the deviation is negative or the rate of change per unit time is negative. The purpose of this assessment is to establish the pressure intensity and rhythm adjustment on a reliable cumulative trend, and to avoid mistaking short-term transient fluctuations for edema accumulation or regression.

[0088] Under the premise of reliable signal, the venous return judgment result is made; the lower limb hemodynamic data are first bandpass filtered to separate the pulsatile component and the slowly changing component, and the pulsatile amplitude stability index and the rise or fall rate index of the slowly changing component are calculated within a fixed window.

[0089] The pulsation amplitude stability index is used to reflect the consistency between local perfusion and signal quality. Specifically, it extracts the peak-to-valley difference of the pulsation component within a window to form a pulsation amplitude sequence and calculates the coefficient of variation of the pulsation amplitude sequence. The smaller the coefficient of variation, the more stable the pulsation amplitude and the more consistent the signal quality. The rising or falling rate index of slowly changing components is used to reflect the overall trend of venous filling and emptying processes. Specifically, it performs linear fitting on the slowly changing components within a window and takes the slope as the rate index. A positive slope indicates an enhanced filling trend, and a negative slope indicates an enhanced emptying trend.

[0090] Subsequently, the pulse amplitude stability index and the rise or fall rate index were compared with the individual reference range under the same posture. During the calibration phase, the individual reference range was established for three postures: supine still, seated still, and standing still. The individual reference range included the reference mean of the pulse amplitude stability index, the reference dispersion of the pulse amplitude stability index, the reference mean of the rise or fall rate index, and the reference dispersion of the rise or fall rate index. In subsequent use, only when the current activity state is supine still, seated still, or standing still, the sensor contact status is determined to be good, and the lower limb hemodynamic data is marked as reliable, is the individual reference range corresponding to the current posture state updated exponentially. The object of the exponential smoothing update is the pulse amplitude stability index corresponding to the current posture state. The reference mean, reference dispersion of the pulse amplitude stability index, reference mean of the rise or fall rate index, and reference dispersion of the rise or fall rate index are all included. Before the exponential smoothing update, abnormal data is excluded. If the normalized deviation of the pulse amplitude stability index exceeds the deviation threshold, or the normalized deviation of the rise or fall rate index exceeds the deviation threshold, or if any of the following situations exist within the acquisition window of the lower limb hemodynamic data: saturation of the DC component of the optical signal, truncation of the DC component of the optical signal, effective amplitude of the pulse component of the optical signal not higher than the preset multiple of the calibration noise floor, or difference between adjacent pulse cycles exceeding the calibration cycle dispersion threshold, the pulse amplitude stability index and the rise or fall rate index will not participate in the individual reference range update.

[0091] After the current fluctuation amplitude stability index and the current rise or fall rate index are excluded from abnormal data, the smoothing coefficient is first determined. The method for determining the smoothing coefficient is as follows: read the trusted acquisition window duration, the number of calibration windows, and the allowed update time; divide the allowed update time by the trusted acquisition window duration to obtain the number of windows corresponding to the allowed update time; then determine the higher of the number of windows corresponding to the allowed update time and the number of calibration windows as the number of update windows; and determine the smoothing coefficient as the reciprocal of the number of update windows. The trusted acquisition window duration is the duration of the acquisition window in which the current fluctuation amplitude stability index and the current rise or fall rate index are located; the number of calibration windows is the number of trusted acquisition windows used when establishing the individual reference range; and the allowed update time is the individual reference range update cycle pre-stored in the device software.

[0092] The exponential smoothing update method for individual reference ranges includes: when updating the reference mean of the pulsation amplitude stability index, first calculate the difference between the current pulsation amplitude stability index and the reference mean of the pulsation amplitude stability index before the update, then multiply the difference by a smoothing coefficient and add it to the reference mean of the pulsation amplitude stability index before the update to obtain the reference mean of the pulsation amplitude stability index after the update; when updating the reference dispersion of the pulsation amplitude stability index, first calculate the absolute difference between the current pulsation amplitude stability index and the reference mean of the pulsation amplitude stability index after the update, and use the absolute difference as the dispersion input of the current pulsation amplitude stability index, then calculate the difference between the dispersion input of the current pulsation amplitude stability index and the reference dispersion of the pulsation amplitude stability index before the update, multiply the difference by a smoothing coefficient and add it to the reference dispersion of the pulsation amplitude stability index before the update to obtain the reference dispersion of the pulsation amplitude stability index after the update.

[0093] When updating the reference mean of the rate of rise or fall indicator, first calculate the difference between the current rate of rise or fall indicator and the reference mean of the rate of rise or fall indicator before the update. Then, multiply the difference by a smoothing coefficient and add it to the reference mean of the rate of rise or fall indicator before the update to obtain the reference mean of the rate of rise or fall indicator after the update. When updating the reference dispersion of the rate of rise or fall indicator, first calculate the absolute difference between the current rate of rise or fall indicator and the reference mean of the rate of rise or fall indicator after the update. Use the absolute difference as the dispersion input of the current rate of rise or fall indicator. Then, calculate the difference between the dispersion input of the current rate of rise or fall indicator and the reference dispersion of the rate of rise or fall indicator before the update. Multiply the difference by a smoothing coefficient and add it to the reference dispersion of the rate of rise or fall indicator before the update to obtain the reference dispersion of the rate of rise or fall indicator after the update.

[0094] The comparison method uses deviation calculation. The difference between the current fluctuation amplitude stability index and the reference mean of the fluctuation amplitude stability index under the same attitude is divided by the reference dispersion of the fluctuation amplitude stability index under the same attitude to obtain the normalized deviation corresponding to the fluctuation amplitude stability index. The difference between the current rise or fall rate index and the reference mean of the rise or fall rate index under the same attitude is divided by the reference dispersion of the rise or fall rate index under the same attitude to obtain the normalized deviation corresponding to the rise or fall rate index. When the normalized deviation corresponding to the fluctuation amplitude stability index is greater than the deviation threshold, and the normalized deviation of the rise or fall rate index calculated according to the preset non-smooth direction is greater than... When the deviation threshold is met, and both of the above conditions are met within each evaluation window covered by the minimum duration, the venous return judgment result is determined to be poor venous return; when the normalized deviation corresponding to the pulsation amplitude stability index and the normalized deviation corresponding to the rise or fall rate index are both less than or equal to the deviation threshold within each evaluation window covered by the minimum duration, and the coefficient of variation of the pulsation amplitude stability index is not higher than the sum of the reference mean and reference dispersion of the pulsation amplitude stability index under the same posture, and the absolute value of the rise or fall rate index is not higher than the sum of the reference mean and reference dispersion of the rise or fall rate index under the same posture, the venous return judgment result is determined to be normal venous return.

[0095] The method for setting the unobstructed direction includes: during the initial wear calibration phase, lower limb hemodynamic data are collected under conditions of lying still, sitting still, and standing still, with the sensor contact status determined to be good; bandpass filtering and slow-changing component extraction are performed on the lower limb hemodynamic data to obtain the optical signal pulsation component and the slow-changing component; the pulsation amplitude stability index is determined by the coefficient of variation of the peak-valley difference sequence of the optical signal pulsation component. An increase in the coefficient of variation corresponds to a decrease in the consistency of the pulsation amplitude, therefore the unobstructed direction of the pulsation amplitude stability index is set to the direction of increasing value; the rise or fall rate index is determined by the fitting slope of the slow-changing component within the evaluation window, with a positive fitting slope corresponding to slow change. As the component increases, a negative fitting slope corresponds to the slow-changing component decreasing. In the scenario of lower limb venous return assistance, the direction of the slow-changing component's increase is set as the unobstructed direction of the increase or decrease rate index. When the device signal polarity configuration makes the direction of the slow-changing component's increase opposite to the direction of venous filling, a pressure disturbance calibration is performed within the calibration window. The pressure disturbance calibration adjusts the current actual pressure from the pressure before the disturbance to the pressure after the disturbance according to the pressure disturbance value. The representative values ​​of the slow-changing component under the pressure before and after the disturbance are calculated respectively. The unobstructed direction of the increase or decrease rate index is determined based on the sign of the difference between the representative value after the disturbance and the representative value before the disturbance, so that the unobstructed direction corresponds to the direction in which venous filling does not decrease before and after pressure is applied.

[0096] The method for setting the minimum duration includes: the sampling period for reading lower limb hemodynamic data, the evaluation window duration, the total cycle duration of the target compression rhythm under the current posture state, and the median of the pulse cycle within the calibration window; firstly, based on the median pulse cycle and the sampling period, a window length that can contain a complete pulse cycle within an evaluation window is determined, and the window length is converted into a first candidate time; then, the total cycle duration of the target compression rhythm is converted into a second candidate time; subsequently, the higher of the first and second candidate times is determined as the minimum duration; when the target compression rhythm has not entered the execution layer, the higher of the evaluation window duration and the first candidate time is determined as the minimum duration; the minimum duration is used to limit the determination of poor return flow to be completed under the same current posture state, the same sensor contact state, and the same data reliability state. If the current posture state changes, the sensor contact state becomes poor, or the lower limb hemodynamic data is marked as unreliable within the minimum duration, the minimum duration is recalculated.

[0097] The method for setting the deviation threshold includes: during the individual reference range establishment phase, the calibration windows for three postures—lying still, sitting still, and standing still—are divided into multiple evaluation windows, and the normalized deviation of the pulsation amplitude stability index and the normalized deviation of the rise or fall rate index are calculated for each evaluation window; the device software pre-stores a set of candidate deviation thresholds, which are arranged in ascending order of value. The lower limit of the candidate deviation threshold set is calculated based on the sampling resolution and reference dispersion, and the upper limit is calculated based on the device's effective range and signal quality judgment boundary; for each current... For each attitude state, candidate deviation thresholds are read sequentially from the candidate deviation threshold set, and it is determined whether the candidate deviation thresholds can cover the normalized deviation of the pulsation amplitude stability index and the normalized deviation of the rise or fall rate index for all evaluation windows within the calibration window under the current attitude state. The first candidate deviation threshold that can complete the coverage is determined as the deviation threshold corresponding to the current attitude state. In subsequent use, after the individual reference range is updated exponentially, the normalized deviation within the most recent reliable evaluation window is recalculated according to the updated reference mean and reference dispersion, and the same candidate deviation threshold set is used to verify the deviation thresholds.

[0098] If the signal in this cycle is reliable, the edema judgment result and the venous return judgment result are output for subsequent target pressure intensity and target pressure rhythm decision-making. If the signal in this cycle is unreliable, the most recently reliable edema judgment result and the most recently reliable venous return judgment result formed in the previous static acquisition stage are output, and their validity is maintained until the static acquisition stage with reliable signal is entered again to complete the update. This ensures that the control strategy remains stable and continuous during posture switching or dynamic activities, and avoids false triggering and frequent switching.

[0099] Based on the current posture, a corresponding baseline compression intensity and rhythm are set. Then, based on the edema assessment and venous return assessment results, the baseline compression intensity and rhythm are adjusted to obtain the target compression intensity and rhythm, specifically including:

[0100] The target pressurization intensity is represented by the target pressure value, and the target pressurization rhythm is represented by four time parameters: inflation duration, pressure holding duration, deflation duration, and interval duration. These outputs will be directly used as the setpoints for subsequent pressure control.

[0101] To ensure the transferability of settings across different devices and individuals, two pre-calibrated individual parameters were introduced: maximum permissible pressure and minimum effective pressure. The maximum permissible pressure constrains the upper limit of safety and comfort. Its setting logic is as follows: under a supine, stationary position, the pressure is increased incrementally in fixed steps, with each step being 0.05 of the preset safety upper limit. Skin perfusion status is assessed based on lower limb hemodynamic data. When the pulsation amplitude in the lower limb hemodynamic data continuously decreases beyond the preset perfusion decline threshold compared to the reference amplitude before adjustment, or when a user-inputted discomfort confirmation signal is received, the pressure increase is stopped, and the pressure level before the cessation of adjustment is determined as the maximum permissible pressure. The minimum effective pressure ensures the lower limit of effective control. Its setting logic is as follows: under three static postures—supine, sitting, and standing—the pressure is increased incrementally in the same increment. When the venous return assessment changes from impaired to normal and the edema assessment changes from increased edema to no increased edema, the corresponding pressure is recorded as the minimum effective pressure for that posture.

[0102] The method for setting the perfusion drop threshold includes: before determining the maximum allowable pressure, acquiring lower limb hemodynamic data under no-pressure or minimum pre-pressure conditions in a supine, stationary state with good sensor contact; extracting the optical signal pulsation component from the lower limb hemodynamic data and dividing it into multiple assessment segments according to a fixed assessment duration; calculating the representative value of the pulsation amplitude for each assessment segment, and using the median of the representative values ​​of the pulsation amplitude of each assessment segment before adjustment as the reference amplitude before adjustment; then calculating the deviation of the representative value of the pulsation amplitude of each assessment segment from the reference amplitude before adjustment, and multiplying the dispersion of the deviation by a fixed safety factor to obtain the natural fluctuation boundary; simultaneously, based on the optical sensor... The sampling resolution, calibration noise floor, and mean amplitude of the pulsation component are used to obtain the device resolution boundary. The higher of the natural fluctuation boundary and the device resolution boundary is determined as the perfusion decline threshold. During the stepwise pressure increase, each pressure level maintains a fixed evaluation time after the device pressure feedback data enters the allowable error range of the corresponding pressure level, and then the representative value of the pulsation amplitude under the corresponding pressure level is calculated. When the decrease in the representative value of the pulsation amplitude under the corresponding pressure level relative to the reference amplitude before the increase exceeds the perfusion decline threshold, and both adjacent evaluation segments within the same pressure level satisfy the condition that the decrease exceeds the perfusion decline threshold, the skin perfusion state corresponding to the lower limb hemodynamic data is determined to have reached the perfusion decline condition.

[0103] When the current posture is standing, the baseline target pressure intensity is set at 0.75 between the minimum effective pressure and the maximum permissible pressure corresponding to standing, i.e., the minimum effective pressure plus 0.75 times the interval width, to counteract the increase in venous return resistance caused by gravity and improve peripheral venous support. When the current posture is sitting, the baseline target pressure intensity is set at 0.55 between the minimum effective pressure and the maximum permissible pressure corresponding to sitting, to compensate for the obstruction of return by lower leg drooping and knee flexion while avoiding excessive pressure discomfort in prolonged sitting. When the current posture is supine, the baseline target pressure intensity is set at 0.35 between the minimum effective pressure and the maximum permissible pressure corresponding to supine, to maintain necessary support and reduce the impact of prolonged continuous pressure on local perfusion.

[0104] The basic target pressurization rhythm is set in conjunction with the current activity state, and the units for inflation duration, holding time, deflation duration, and rest duration are all seconds. The total cycle duration is the sum of the inflation duration, holding time, deflation duration, and rest duration, also in seconds. When the current activity state is standing or sitting still, the basic target pressurization rhythm is set to an inflation duration of 6 seconds, a holding time of 3 seconds, a deflation duration of 4 seconds, and a rest duration of 17 seconds, making each cycle 30 seconds and forming a stable periodic compression to improve the reflux driving force. When the current activity state is lying still, the basic target pressurization rhythm is set to an inflation duration of 6 seconds, a holding time of 3 seconds, a deflation duration of 4 seconds, and a rest duration of 17 seconds, making each cycle 30 seconds and forming a stable periodic compression to improve the reflux driving force. The cycle duration is 3 seconds, the deflation duration is 4 seconds, and the interval duration is 47 seconds, making each cycle 60 seconds to maintain a low-frequency cycle under low gravity load and prevent stagnation. When the current activity state is slow walking, normal walking, fast walking, climbing stairs, or running, the basic target pressurization rhythm is set to an inflation duration of 0, a holding duration of 0, a deflation duration of 0, and an interval duration of 60 seconds. The basic target pressurization intensity is also adjusted to 0.45 between the minimum effective pressure and the maximum allowable pressure corresponding to the current posture state, thereby entrusting the main return flow drive to the muscle pump and avoiding discomfort or blood flow interference caused by pulse compression and gait phase superposition.

[0105] Please see Figure 2 As shown, after obtaining the baseline target compression intensity and rhythm, the baseline compression intensity and rhythm are quantitatively fine-tuned based on the edema assessment and venous return assessment results. The pressure adjustment step is set to 0.1 times the difference between the maximum allowable pressure and the minimum effective pressure corresponding to the current posture state, rounded up. This ensures that each adjustment amplitude exceeds the measurement noise and forms a perceptible change in therapeutic effect, while avoiding abrupt changes due to excessively large steps. The interval duration adjustment step is set to a fixed 5-second step, which is used to adjust the compression frequency by shortening or lengthening the interval duration without changing the mechanical time constraints of inflation, holding, and deflation.

[0106] If only one of the edema assessment results is increased edema or only one of the venous return assessment results is impaired venous return, then the baseline pressure intensity is increased by a second number of pressure adjustment steps, and the interval duration of the baseline pressure rhythm is decreased by a second number of interval duration adjustment steps. If the edema assessment result is increased edema and the venous return assessment result is impaired venous return, then the baseline pressure intensity is increased by a first number of pressure adjustment steps, and the interval duration of the baseline pressure rhythm is decreased by a first number of interval duration adjustment steps. If the edema assessment result is not increased edema and the venous return assessment result is normal venous return, then the baseline pressure intensity is decreased by a second number of pressure adjustment steps, but must not be lower than the minimum effective pressure corresponding to the current posture, and the interval duration of the baseline pressure rhythm is increased by a second number of interval duration adjustment steps.

[0107] In one implementation, if the edema assessment indicates increased edema, the target compression intensity is increased by one pressure adjustment step compared to the baseline target compression intensity, and the interval duration of the target compression rhythm is decreased by one interval duration adjustment step compared to the baseline target compression rhythm. This increases the average peripheral support and the number of compressions per unit time, aiming to inhibit further extravasation of tissue fluid and accelerate interstitial fluid return. If the venous return assessment indicates poor venous return, the target compression intensity is increased by one pressure adjustment step compared to the baseline target compression intensity, and the target compression rhythm is... The intermittent duration is reduced by one intermittent duration adjustment step from the intermittent duration of the baseline target pressurization rhythm, with the aim of increasing the proximal venous propulsion pressure and the frequency of periodic pumping to improve centripetal return. If the edema assessment indicates increased edema and the venous return assessment indicates impaired return, the target pressurization intensity is increased by two pressure adjustment steps from the baseline target pressurization intensity, and the intermittent duration of the target pressurization rhythm is reduced by two intermittent duration adjustment steps from the intermittent duration of the baseline target pressurization rhythm, with the aim of providing stronger intervention when fluid accumulation and restricted return coexist.

[0108] If the edema assessment result is non-increased edema and the venous return assessment result is normal venous return, then the target pressure intensity is reduced by one pressure adjustment step from the base target pressure intensity, but must not be lower than the minimum effective pressure corresponding to the current posture state. The interval duration of the target pressure rhythm is increased by one interval duration adjustment step from the interval duration of the base target pressure rhythm. The purpose is to reduce unnecessary pressure exposure and improve comfort while meeting the minimum effective support.

[0109] All fine-tuned target pressurization intensities must be compared with the maximum permissible pressure. If the maximum permissible pressure is exceeded, the target pressurization intensity will be clamped to the maximum permissible pressure. All fine-tuned target pressurization rhythm parameters must meet the requirements that the interval duration is not less than 0 and the total cycle duration is not less than 20 seconds, in order to ensure the physical feasibility of the gas path and valve control execution and avoid the risk of discomfort caused by excessively dense pulses.

[0110] Pressure control is performed based on attitude switching indicators, target pressurization intensity, and target pressurization rhythm. The pressurization intensity and rhythm are adjusted in real time based on equipment pressure feedback data. Specifically, this includes:

[0111] Feedback control is performed with the control cycle as the discrete time reference. The control cycle is set to 0.1 seconds. In each control cycle, the equipment pressure feedback data is filtered by sliding mean to obtain the current actual pressure. The sliding window length is set to 10 control cycles to suppress the direct disturbance of the control command by the instantaneous noise of the pressure sensor.

[0112] The pressure error is then calculated, which equals the target pressurization intensity minus the current actual pressure. This pressure error is used as the unified driving force for subsequent pressure regulation and rhythm transition. The output is a pressure control command, which consists of the air pump drive duty cycle, the inflation valve opening, and the exhaust valve opening. The calculation is based on the pressure change rate and actuator control quantity mapping table obtained from the equipment's factory calibration. This mapping table uses the current actual pressure as an index and provides the pressure change per unit time under different combinations of air pump drive duty cycles, inflation valve openings, and exhaust valve openings. This is used to convert the expected pressure increment and expected pressure decrement calculated by the control algorithm into executable pressure control commands, so that the control algorithm can still execute according to the target pressure trajectory under different air path impedances and different airbag volumes.

[0113] The factory calibration method for the pressure change rate and actuator control quantity mapping table includes: During the production testing phase, connecting the standard load airbag and standard pipeline to the device under test, and fixing the standard load airbag on a standard phantom with calibrated elastic modulus; the method for obtaining the standard phantom with calibrated elastic modulus is as follows: first, determine the phantom size, contact surface, and qualified compression range of the phantom based on the design circumference of the smart pressure sock coverage area, the contact area of ​​the standard load airbag, the minimum effective pressure, and the maximum allowable pressure; the qualified compression range of the phantom is jointly determined by the load corresponding to the minimum effective pressure, the load corresponding to the maximum allowable pressure, and the compression displacement allowed to be generated by the standard load airbag under the corresponding load; then, place the candidate phantom into the compression test fixture, and the compression test fixture is configured according to the load corresponding to the minimum effective pressure and the load corresponding to the maximum allowable pressure. The candidate phantom is subjected to a load and an intermediate load between them, and the compression displacement of the candidate phantom is recorded after each load is sampled for a fixed duration. When the compression displacement of the candidate phantom under each load falls within the qualified compression range of the phantom, and the difference in compression displacement obtained from two adjacent repeated loadings does not exceed the phantom displacement error limit, the candidate phantom is determined as a standard phantom with calibrated elastic modulus. The phantom displacement error limit is determined based on the displacement sampling resolution of the compression test fixture and the minimum resolvable compression displacement of the standard load airbag between the minimum effective pressure and the maximum allowable pressure. The load conditions in the production test stage are limited by the standard phantom with calibrated elastic modulus, so that the factory calibration results of the pressure change rate and actuator control quantity mapping table can correspond to the fixed air circuit load composed of the standard load airbag, standard pipeline and the device under test.

[0114] Subsequently, the actuator is scanned and excited under multiple discrete pressure platforms. That is, the current actual pressure is maintained at the preset platform value through closed loop, and a set of discrete combinations of air pump drive duty cycle, air valve opening and air valve opening are applied in sequence. Under each combination, a fixed sampling time is maintained and the slope of the equipment pressure feedback data over time is recorded. This slope is written as the pressure change per unit time into the index position corresponding to the current actual pressure platform in the pressure change rate and actuator control quantity mapping table.

[0115] To cover the full range of the equipment, the preset platform value interval is taken as the pressure adjustment step. Its setting logic is to take 0.1 of the difference between the maximum allowable pressure and the minimum effective pressure and round it up, so that the pressure index resolution of the pressure change rate and actuator control quantity mapping table can cover the control target resolution without introducing excessive storage and calibration costs.

[0116] After scanning all pressure platforms and actuator combinations, the mapping table between pressure change rate and actuator control quantity is subjected to monotonicity and continuity constraints. Specifically, the pressure change per unit time under the same pressure platform is sorted according to the magnitude of the actuator control quantity and outliers are eliminated. Then, linear interpolation is performed between adjacent pressure platforms to generate a continuous index, thereby ensuring that there are no unreasonable non-monotonic jumps during online table lookup and improving the predictability of control.

[0117] Through the above factory calibration, the pressure change rate and actuator control quantity mapping table can reflect the dynamic characteristics of the air circuit under standard operating conditions and provide an initial usable mapping basis for online control.

[0118] To ensure a smooth and safe transition, the maximum pressure increase and decrease increments per second are first set. Both increments are determined by the maximum permissible pressure. The maximum pressure increase increment per second is set to 0.1 times the maximum permissible pressure, and the maximum pressure decrease increment per second is set to 0.08 times the maximum permissible pressure. The logic is that during the ascent phase, support needs to be established more quickly to offset the sudden increase in venous load caused by posture changes, while during the descent phase, release needs to be slower to avoid instantaneous loss of support leading to interruption of reflux assistance and sudden changes in body sensation. At the same time, in the high-pressure segment, the airbag compliance decreases and the pressure is more prone to overshoot. Therefore, determining the increment threshold proportionally to the maximum permissible pressure allows the ascent and descent slopes of different individuals to adaptively converge with the safety upper limit.

[0119] Set a pressure dead zone threshold, which is 0.5 of the pressure adjustment step, so that the actuator does not move when the pressure error falls into the dead zone, thus avoiding high-frequency jitter caused by sensor quantization error.

[0120] When the attitude switching flag is true and the target pressurization intensity is higher than the current actual pressure, a rapid response pressure increase is executed. This process adopts a combination of phased increase and closed-loop fine adjustment: the coarse adjustment phase is the time interval from the start of this rapid response pressure increase to the pressure error being reduced to within 0.3 of the initial pressure error. During this time interval, the pressure trajectory with controlled slope is mainly used to advance, prioritizing the timeliness of establishing support, and the exhaust valve opening is fixed at 0 to avoid charge and discharge collisions. At the same time, integral accumulation is not introduced to avoid overshoot amplification in the large error range.

[0121] During the coarse adjustment phase, the pressure error entering the coarse adjustment phase is recorded as the initial pressure error. Based on the initial pressure error, the expected pressure increment for the current control cycle is calculated. The expected pressure increment is equal to the smaller of the absolute value of the pressure error and the maximum pressure increase per second multiplied by the control cycle. The pressure trajectory point is updated accordingly. The pressure trajectory point for the next control cycle is equal to the current actual pressure plus the expected pressure increment.

[0122] Subsequently, based on the pressure change rate and actuator control quantity mapping table, the air pump drive duty cycle and air charging valve opening that match the desired pressure increment are selected. At the same time, the exhaust valve opening is set to 0 to avoid air charging and discharging conflict, so as to approach the target pressurization intensity as quickly as possible while ensuring that the pressure rise per second does not exceed the threshold.

[0123] When the pressure error decreases to below a preset percentage of the initial pressure error, the fine-tuning stage begins. This preset percentage is obtained through pressure step response calibration, which is completed during the equipment's factory calibration phase. During calibration, under different airbag volumes, different air path impedances, and different material compliances, the actual pressure is increased from the initial test pressure to the target test pressure. The pressure overshoot and the time required to reach the target pressure intensity are recorded when the pressure error decreases from the initial pressure error to different residual error percentages. The preset percentage is selected as the residual error percentage where the pressure overshoot is below the preset overshoot limit and the time required to reach the target pressure intensity does not exceed the response time limit. The response time limit is obtained through pressure step response calibration. During the pressure step response calibration process, for each set of initial and target test pressures, the initial pressure error, control cycle, and... The maximum pressure increase increment per second and the inflation duration in the target pressurization rhythm are used as the parameters. Then, based on the initial pressure error and the maximum pressure increase increment per second, the pressure-limited rise time is determined, and the pressure-limited rise time is added to the command update time corresponding to one control cycle as a candidate response time. When the candidate response time is less than the inflation duration in the target pressurization rhythm, the candidate response time is determined as the response time limit. When the candidate response time is not less than the inflation duration in the target pressurization rhythm, the inflation duration in the target pressurization rhythm is determined as the response time limit. When the time required to reach the target pressurization intensity recorded in the pressure step response calibration does not exceed the response time limit, the corresponding residual error ratio is retained as an optional residual error ratio. Among all optional residual error ratios, the residual error ratio with the lowest pressure overshoot (below the preset overshoot limit) and the shortest time required to reach the target pressurization intensity is selected as the preset ratio.

[0124] The preset overshoot limit is determined by the difference between the maximum allowable pressure and the minimum effective pressure corresponding to the current attitude state, and is used to limit the pressure overshoot before and after entering the fine-tuning stage. The fine-tuning stage uses a proportional-integral closed loop to control the pressurization intensity. The proportional coefficient and integral coefficient are obtained through pressure step response calibration. The selection of the proportional coefficient and integral coefficient should ensure that the pressure overshoot in the fine-tuning stage is lower than the preset overshoot limit, and that the pressure error of the current actual pressure near the target pressurization intensity enters the pressure dead zone threshold. The control increment is jointly determined by the pressure error adjustment corresponding to the proportional coefficient and the pressure error accumulation adjustment corresponding to the integral coefficient. The control increment is mapped to the increment of the air pump drive duty cycle, and the air pump drive duty cycle is limited to between 0 and 1.

[0125] The above setting logic is that the coarse adjustment stage mainly satisfies the timeliness and ensures that no sudden changes occur with the slope threshold. The fine adjustment stage mainly eliminates the remaining error and offsets the steady-state deviation caused by air leakage and material rebound through the integral term. In this way, it can quickly form support when the standing load increases, and avoid overshooting when approaching the target pressure, which will cause discomfort.

[0126] When the posture switching flag is true and the target pressure intensity is lower than the current actual pressure, the pressure is delayed and slowly reduced. The process first sets a delay confirmation time, for example, setting the delay confirmation time to 3 seconds. The setting logic of the delay confirmation time is consistent with the short time threshold, so that the pressure release only occurs after the posture switching has been confirmed to be stable, thereby avoiding the frequent opening and closing of pressure caused by short-term sitting and standing back and forth movements.

[0127] During the delayed confirmation period, the pressure control command of the previous cycle remains unchanged, while the target pressurization rhythm is updated to the new target pressurization rhythm without immediately changing the pressure level, so as to ensure that support continues during the transition phase and avoid sudden changes in the body sensation caused by the superposition of rhythm change and pressure drop.

[0128] After the delayed confirmation period, a slow pressure relief phase begins. Within each control cycle, the expected pressure reduction is calculated. This expected pressure reduction is equal to the smaller of the absolute value of the pressure error and the maximum pressure drop per second multiplied by the control cycle. Based on this, the required pressure drop per unit time for the current control cycle is determined. Subsequently, the pressure relief execution mode is selected based on the pressure change rate and actuator control quantity mapping table. The selection is automatic, based on the current actual pressure range and the actuator's achievable pressure change rate, to ensure that the pressure relief trajectory meets the constraint of the maximum pressure drop per second and to avoid pressure relief failure in low-pressure ranges or excessively rapid pressure relief in high-pressure ranges.

[0129] Specifically, when the current actual pressure is higher than the target pressurization intensity and the pressure change rate and actuator control quantity mapping table show that the pressure drop per unit time can reach the desired pressure reduction by simply increasing the opening of the exhaust valve in the current actual pressure range, the air pump drive duty cycle is reduced to 0 and kept at 0. At the same time, the exhaust valve opening is increased according to the pressure change rate and actuator control quantity mapping table to the target opening that meets the desired pressure reduction, and the inflation valve opening is set to 0. Thus, the exhaust valve opening is used as the only adjustment quantity to achieve fine and controllable pressure relief, avoiding pressure fluctuations caused by the air pump's residual inflation capacity and the parallel exhaust.

[0130] When the pressure change rate and actuator control quantity mapping table shows that the exhaust valve opening has reached its maximum available opening in the current actual pressure range but is still insufficient to provide the desired pressure reduction, the air pump active pressure relief mode is executed. In the air pump active pressure relief mode, the exhaust valve opening is set to the maximum available opening corresponding to the pressure change rate and actuator control quantity mapping table, and the air pump drive duty cycle is reduced to 0 and maintained at 0. Then, the pressure relief capacity is supplemented by opening the reverse pressure relief passage or low resistance exhaust passage of the equipment. The reverse pressure relief passage or low resistance exhaust passage is a controllable channel preset in the air circuit structure, and its opening amount is also given by the pressure change rate and actuator control quantity mapping table so that the pressure drop per unit time reaches the desired pressure reduction.

[0131] In the medium-to-high pressure range, the vent valve opening is prioritized to achieve continuously adjustable pressure relief slope control. Only when the vent valve opening reaches its upper limit and is still insufficient to meet the desired pressure reduction is the additional pressure relief channel provided by the air circuit activated to ensure unrestricted pressure relief capacity. This allows for controlled, gradual pressure relief across the entire pressure range, based on the maximum pressure drop increment per second. Throughout the entire slow pressure relief phase, the inflation valve opening is always set to 0 to avoid simultaneous inflation and deflation, which could cause oscillations in the pressure curve and introduce unnecessary abrupt changes in perceived pressure.

[0132] When the absolute value of the pressure error decreases to within the pressure regulation step, the fine-tuning stage begins. The fine-tuning stage uses the same proportional-integral closed loop as the rising stage, but maps the control quantity to the fine adjustment of the exhaust valve opening to eliminate residual deviations caused by valve dead zone and airbag hysteresis.

[0133] The purpose of this approach is to transform the pressure release process from a sudden drop into a predictable slope trajectory, thereby reducing the instantaneous interruption of venous return assistance after changes in posture and lowering the risk of discomfort and perfusion fluctuations caused by sudden changes in local tissue stress.

[0134] When the posture switching flag is false and the target pressure intensity and rhythm change relative to the previous control cycle, fine-tuning and rhythm transition are performed. These changes originate from the update results of the target pressure intensity and rhythm decision steps regarding the current posture, current activity level, edema assessment, and venous return assessment. Therefore, without a posture switch, the system needs to maintain consistency between the current actual pressure and the new target pressure intensity and rhythm without introducing significant perceptual fluctuations. To this end, such changes are uniformly considered minor, and a combination of pressure fine-tuning and gradual rhythm replacement is used to complete the transition. The aim is to suppress pressure fluctuations caused by frequent updates while ensuring that the target adjustment is accurately reflected in the pressure output.

[0135] Pressure fine-tuning employs a dead-zone plus slope limiting strategy. A pressure dead-zone threshold is set, for example, to 0.5 of the pressure adjustment step, so that the pressure dead-zone threshold can cover the natural fluctuations caused by pressure sensor noise and micro-leakage in the air path, avoiding repeated operation of the actuator due to small errors.

[0136] If the absolute value of the pressure error does not exceed the pressure dead zone threshold, the pressure control command remains unchanged, so that the current actual pressure remains stable under the action of natural rebound and slow leakage.

[0137] If the absolute value of the pressure error exceeds the pressure dead zone threshold, the system enters fine-tuning mode. The maximum pressure increase per second and the maximum pressure decrease per second are multiplied by 0.25 to obtain the slope threshold. The expected pressure increment or expected pressure decrease for each control cycle is calculated based on this slope threshold. The air pump drive duty cycle, air valve opening, and air valve opening are updated through the pressure change rate and actuator control quantity mapping table, so that the current actual pressure slowly approaches the target pressurization intensity with a limited slope.

[0138] The above setting logic is that when the posture switching flag is false, the system is in a relatively stable state. The target changes are mostly caused by the update of the edema judgment result or the venous return judgment result. If the slope at the posture switching time is still executed, it will cause unnecessary force changes. Therefore, the slope is contracted by a fixed ratio to control the somatosensory fluctuation and reduce the false trigger amplification effect.

[0139] For changes in the target pressurization rhythm, a gradual parameter replacement is used instead of a one-time jump. The system saves the inflation duration, holding duration, deflation duration, and interval duration of the currently executed rhythm, and calculates the difference between these parameters and the corresponding parameters in the target pressurization rhythm. At the end of each rhythm cycle, only parameters with non-zero differences are updated once according to the rhythm adjustment step, bringing them closer to the target value, until all four rhythm time parameters converge to the target pressurization rhythm, at which point the rhythm transition ends. The rhythm adjustment step is set to 1, and its threshold setting logic uses 1 as the minimum update resolution for the time parameters to match the smallest time quantization unit that allows for stable response of valve control and airbag inflation / deflation dynamics, thereby avoiding sudden pulse sensations caused by abrupt changes in the cycle structure and reducing pressure waveform distortion caused by rhythm jumps.

[0140] During the rhythm transition, the pressure control still uses the target pressure trajectory point corresponding to the current cycle to generate the target pressure intensity and as a closed-loop reference, ensuring that even if the rhythm parameters are in transition, the current actual pressure can change along a continuous trajectory, thereby avoiding pressure waveform distortion caused by rhythm changes.

[0141] To prevent the target inflation intensity and target inflation rhythm from being repeatedly written to the execution layer within adjacent control cycles, a minimum maintenance time is set, and time gating is used to limit the update frequency of the target inflation intensity and target inflation rhythm. The minimum maintenance time is set to the greater of two times the total cycle duration of the target inflation rhythm and 20 seconds, where the total cycle duration equals the sum of inflation duration, holding duration, deflation duration, and interval duration. The minimum maintenance time is set based on the principle that after the target inflation rhythm is written to the execution layer, the execution layer must complete at least two full inflation cycles, and the lower limb volume change data and lower limb hemodynamic data must enter the next reliable sampling after two full inflation cycles. The evaluation process involves the following steps: When a new target pressurization intensity or rhythm is generated before two complete pressurization cycles are completed, the new target pressurization intensity or rhythm is not written to the execution layer until the difference between the current time and the timestamp of the last time it was written to the execution layer reaches the minimum maintenance time. A minimum maintenance time of 20 seconds is set to ensure that after the target pressurization intensity and rhythm are written to the execution layer, the equipment pressure feedback data can complete at least one complete execution record of the pressure rise, pressure holding, pressure drop, and intermittent phases, and provide a sampling basis under the same execution state for the next edema judgment result and venous return judgment result.

[0142] The system records the timestamp of the last time the target pressurization intensity and target pressurization rhythm were written to the execution layer. If the difference between the current timestamp and the previous timestamp is less than the minimum maintenance time, then unless a safety constraint trigger condition occurs, the system will not accept new target pressurization intensity and target pressurization rhythm being written to the execution layer. The safety constraint trigger condition is defined as the current actual pressure exceeding the maximum allowable pressure or the current actual pressure being lower than the minimum effective pressure corresponding to the current attitude state, thereby prioritizing safety and minimum effective support in extreme cases.

[0143] Finally, a pressure control command is received and sent to the pressurization equipment for execution. In each control cycle, the execution layer drives the air pump and valve control mechanism to produce corresponding inflation and deflation actions according to the pressure control command, so that the current actual pressure changes along the pressure trajectory determined by the target pressurization intensity and target pressurization rhythm. In subsequent control cycles, the equipment pressure feedback data continues to be collected and the current actual pressure and pressure error are updated, thus forming a closed-loop monitoring and closed-loop correction, ensuring that the pressure output under attitude switching and physiological state changes is both timely and smooth.

[0144] This embodiment enables intelligent control of the compression device when the user's posture changes frequently. By implementing the solution in this embodiment, compression stockings and other compression devices can automatically match the appropriate compression intensity and rhythm during different states such as standing, walking, sitting, and lying down, as well as during transitions. This ensures the continuity of venous return while avoiding discomfort and risks caused by excessive compression. The entire control process is smooth and gradual, reducing sudden changes in pressure output and false triggering. In the long run, this will improve user comfort and compliance, achieving a more stable and effective improvement in venous return and control of edema.

[0145] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for controlling lower limb pressure in smart compression stockings, characterized in that, include: Real-time acquisition of body posture sensing data, lower limb volume change data, lower limb hemodynamic data, and equipment pressure feedback data; Based on body posture sensing data, the current posture state and current activity state are identified; Compare the current attitude state with the attitude state at the previous moment to determine whether an attitude transition has occurred, and set an attitude transition flag. Based on the current activity status, determine whether the lower limb volume change data and lower limb hemodynamic data are reliable; If the data on lower limb volume change and lower limb hemodynamics are reliable, then the edema assessment result can be obtained based on the lower limb volume change data, and the venous return assessment result can be obtained based on the lower limb hemodynamics data. Based on the current posture, the corresponding baseline compression intensity and baseline compression rhythm are set, and based on the edema assessment results and venous return assessment results, the baseline compression intensity and baseline compression rhythm are adjusted to obtain the target compression intensity and target compression rhythm. Pressure control is performed based on attitude switching indicators, target pressurization intensity, and target pressurization rhythm, and the pressurization intensity and rhythm are adjusted in real time based on equipment pressure feedback data.

2. The method for controlling lower limb pressure in a smart compression sock according to claim 1, characterized in that, Current posture includes lying down, sitting, and standing; current activity includes lying still, sitting still, standing still, walking slowly, walking normally, walking quickly, going up and down stairs, and running.

3. The method for controlling lower limb pressure in a smart compression sock according to claim 2, characterized in that, The contact status of the sensor is determined based on the DC component of the optical signal, the pulsating component of the optical signal, and the impedance or circumference sampling stability of the lower limb hemodynamic data and the lower limb volume change data. If the current activity state is slow walking, normal walking, fast walking, going up and down stairs, or running, it is determined to be in the dynamic data collection stage, and the lower limb hemodynamic data and lower limb volume change data are marked as unreliable; If the current activity state is in a lying, sitting, or standing position, the static data acquisition phase begins, and the sensor contact status is determined. If the sensor contact status is determined to be good, the lower limb hemodynamic data and lower limb volume change data are marked as reliable.

4. The method for controlling lower limb pressure in a smart compression sock according to claim 1, characterized in that, Pre-set the maximum allowable pressure, the minimum effective pressure corresponding to each posture state, and the interval duration adjustment step; The pressure adjustment step is set based on the maximum allowable pressure and the minimum effective pressure corresponding to the current attitude state. If the edema assessment result is increased edema and the venous return assessment result is poor venous return, then increase the baseline compression intensity by the first number of pressure adjustment steps and decrease the interval duration of the baseline compression rhythm by the first number of interval duration adjustment steps. If only one of the edema assessment results is increased edema or only one of the venous return assessment results is poor venous return, then the basal compression intensity is increased by a second number of pressure adjustment steps, and the interval duration of the basal compression rhythm is decreased by a second number of interval duration adjustment steps. If the edema assessment result is non-increased edema and the venous return assessment result is normal venous return, then the baseline compression intensity is reduced by the second number of pressure adjustment steps, but must not be lower than the minimum effective pressure corresponding to the current posture state, and the interval duration of the baseline compression rhythm is increased by the second number of interval duration adjustment steps.

5. The method for controlling lower limb pressure in a smart compression sock according to claim 4, characterized in that, Both the first quantity and the second quantity are preset positive integers, and the first quantity is greater than the second quantity; the first quantity and the second quantity are predetermined based on the maximum allowable pressure, the minimum effective pressure corresponding to the current attitude state, and the setting result of the pressure adjustment step. The target pressurization intensity shall not exceed the maximum permissible pressure.

6. The method for controlling lower limb pressure in a smart compression sock according to claim 4, characterized in that, Based on the maximum allowable pressure, set the maximum pressure increase increment per second and the maximum pressure decrease increment per second; in each control cycle, perform sliding mean filtering on the equipment pressure feedback data to obtain the current actual pressure; subtract the current actual pressure from the target pressurization intensity to obtain the pressure error; A pre-defined mapping table between pressure change rate and actuator control quantity is prepared. The mapping table uses the current actual pressure as an index to provide the pressure change per unit time under different combinations of air pump drive duty cycle, air valve opening degree, and air valve opening degree.

7. The method for controlling lower limb pressure in a smart compression sock according to claim 6, characterized in that, When the attitude switching flag is true and the target pressure intensity is higher than the current actual pressure, the pressure is increased by combining the coarse adjustment stage and the fine adjustment stage.

8. The method for controlling lower limb pressure in a smart compression sock according to claim 7, characterized in that, During the coarse adjustment phase, the pressure error entering the coarse adjustment phase is recorded as the initial pressure error, and the expected pressure increment for the current control cycle is calculated based on the current pressure error, the maximum pressure increase per second, and the control cycle. Based on the pressure change rate and actuator control quantity mapping table, select the air pump drive duty cycle and air valve opening that match the desired pressure increment, and set the exhaust valve opening to 0; when the current pressure error decreases to below the preset proportion of the initial pressure error, enter the fine-tuning stage.

9. The method for controlling lower limb pressure in a smart compression sock according to claim 7, characterized in that, During the fine-tuning stage, proportional-integral closed-loop control is used to control the pressurization intensity. The proportional coefficient and integral coefficient in the proportional-integral closed-loop control are obtained through pressure step response calibration. The control quantity increment in the proportional-integral closed-loop control is mapped to the increment of the air pump drive duty cycle, and the air pump drive duty cycle is limited to between 0 and 1.

10. The method for controlling lower limb pressure in a smart compression sock according to claim 6, characterized in that, When the attitude switching flag is true and the target pressurization intensity is lower than the current actual pressure, the currently used pressurization rhythm will be updated to the target pressurization rhythm within a preset delay confirmation time. After the delayed confirmation time ends, the expected pressure reduction for this control cycle is calculated based on the pressure error, and the opening of the exhaust valve is increased according to the pressure change rate and actuator control quantity mapping table based on the expected pressure reduction. When the pressure change rate and actuator control quantity mapping table shows that the exhaust valve opening has reached the maximum available opening in the current actual pressure range and is still insufficient to provide the desired pressure reduction, the air pump drive duty cycle is reduced to 0, the air charging valve opening is set to 0, and the preset low-resistance exhaust passage or reverse pressure relief passage is opened to supplement the desired pressure reduction.

11. The method for controlling lower limb pressure in a smart compression sock according to claim 6, characterized in that, When the attitude switching flag is false, and the target pressurization intensity and target pressurization rhythm change relative to the target pressurization intensity and target pressurization rhythm of the previous control cycle, the pressure dead zone threshold is set based on the pressure regulation step. If the absolute value of the pressure error does not exceed the pressure dead zone threshold, the pressure control command remains unchanged. If the absolute value of the pressure error exceeds the pressure dead zone threshold, a slope threshold is set based on the maximum pressure increase per second and the maximum pressure decrease per second. The expected pressure increment or expected pressure decrease for each control cycle is calculated according to the slope threshold. Then, the air pump drive duty cycle, air valve opening, and exhaust valve opening are updated through the pressure change rate and actuator control quantity mapping table.

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