An air cushion pressure control method, a pressure sore prevention air bag air cushion system and an air cushion base

Abstract

The application discloses an air cushion pressure control method, an anti-pressure sore air bag air cushion system and an air cushion base, and relates to the technical field of medical devices. The air cushion pressure control method comprises the following steps: S1, determining the active decompression trigger time interval T of the air bag array; S2, pre-inflating a plurality of independent air bags on the air cushion; S3, collecting a pressure distribution matrix under the current use state; S4, identifying the target air bag position where the local peak pressure is located and the adjacent peripheral air bag set corresponding to the target air bag; S5, controlling the target air bag to deflate and reduce pressure, and simultaneously controlling the peripheral air bag set to inflate and increase pressure; and S6, repeating steps S3 to S5. The application realizes active and accurate pressure sore prevention by constructing a pressure distribution matrix in real time through a flexible pressure sensor array, accurately identifying a local peak pressure point by using an algorithm, and adopting a differentiated adjustment strategy of target high-pressure bag deflation and neighborhood air bag coordinated inflation.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to an air cushion pressure control method, an anti-pressure ulcer airbag cushion system, and an air cushion base. Background Technology

[0002] Pressure ulcers are soft tissue ulcers caused by prolonged pressure on local tissues, leading to persistent ischemia, hypoxia, and malnutrition. They are one of the most common complications in paraplegic patients who use wheelchairs, elderly people with limited mobility, and those who are bedridden for extended periods. Epidemiological statistics show that the incidence of pressure ulcers in spinal cord injury patients in my country is as high as 30%-60%, with the ischial tuberosity and sacrococcygeal region being the most common pressure sites. Once pressure ulcers develop, they not only cause immense suffering for patients but can also lead to serious infections and even endanger life, while significantly increasing medical care costs.

[0003] To prevent and alleviate pressure ulcers, various types of pressure ulcer prevention air cushions are widely used in clinical practice. Currently, pressure ulcer prevention air cushions have mainly gone through the following development stages: First generation: Passive static air cushion. These types of air cushions typically use high-density sponge, gel, or ordinary inflatable air bladders as cushioning media. Their principle is to increase the contact area between the buttocks and the air cushion through material deformation, thereby reducing localized pressure. However, these air cushions have significant drawbacks: sponges and gels undergo creep and compression hardening after bearing the weight of the body, making it impossible to dynamically adjust the support force according to changes; while ordinary inflatable air bladders have a certain degree of elasticity, gas flow is restricted under pressure, still creating localized high-pressure points. Therefore, passive air cushions can only delay the occurrence of pressure sores to a certain extent and cannot achieve true active pressure relief.

[0004] Second generation: Alternating inflatable air cushion. To overcome the shortcomings of static air cushions, "alternating inflation" air cushions consisting of 2-4 independent air chambers have emerged. These air cushions use a timer to control an air pump to alternately inflate and deflate two sets of air chambers, attempting to improve local blood circulation through periodic pressure changes. For example, Chinese invention patent CN101999978A discloses a double-layer pulsed air circulation anti-bedsore air cushion that achieves a massage effect through the alternating inflation and deflation of the upper and lower air bladders. However, the zoning of these air cushions is extremely coarse (only 2-4 zones), failing to accurately adapt to the differences in the contours of minute bony prominences such as the ischial tuberosity and greater trochanter of the femur; furthermore, their alternation cycle is fixed, unable to dynamically respond to the patient's actual pressure conditions, resulting in limited pressure relief.

[0005] Third generation: Multi-airbag independently adjustable air cushion. In recent years, to improve decompression accuracy, matrix-type air cushions containing dozens of independent airbags have emerged. For example, Chinese utility model patent CN221490458U discloses an inflatable air cushion device, in which an 8×8 array of 64 independent airbags is laid on the air cushion base, and a flexible pressure sensor and controller are provided to regulate the inflation and deflation of the airbags by monitoring the pressure value. Although this type of air cushion has the basis for fine partitioning in its structure, the following technical problems still need to be solved in practical applications: The gas path structure is complex and has poor reliability. Existing multi-airbag cushioning systems typically use external PU tubing to connect each airbag to the solenoid valve. 64 airbags mean 64 independent air tubes and dozens of quick-connect fittings. This structure not only results in messy internal tubing and bulky size, but also a high risk of leakage due to the numerous fittings. Once a leak occurs, the balance and stability of the entire cushioning system are compromised, making maintenance extremely difficult.

[0006] The control strategy is crude and ineffective in reducing stress. Existing control methods mostly rely on overall pressure equalization or zone feedback, meaning that once the pressure in a certain area exceeds a threshold, all airbags in that area are inflated and deflated uniformly. This strategy cannot identify the true "pressure extreme point." In reality, pressure ulcers often occur at very small bony prominences such as the ischial tuberosity. Current technology cannot precisely target and release pressure at these high-pressure points, nor can it effectively disperse pressure through the coordinated inflation of surrounding airbags, resulting in a significant reduction in pressure relief.

[0007] In summary, existing pressure ulcer prevention air cushions generally suffer from complex and easily damaged air circuit structures and inaccurate pressure reduction control strategies, resulting in unsatisfactory pressure ulcer prevention effects. There is an urgent need for a new type of intelligent pressure ulcer prevention air cushion system with reliable structure and precise control. Summary of the Invention

[0008] On one hand, the present invention provides a method for controlling air cushion pressure, comprising the following steps: S1. Obtain the user's pressure ulcer risk parameter, which is the Braden pressure ulcer risk assessment score; Based on the Braden score, determine the active decompression triggering time interval T of the airbag array from the preset Braden score – active decompression adjustment cycle mapping table; S2. After the system is powered on, it pre-inflates the multiple independent airbags arranged in an m×n matrix on the air cushion to the reference pressure. S3. The pressure distribution matrix under the current use state is collected by a flexible pressure sensor array laid on the air cushion bearing surface. The sensing units of the pressure distribution matrix correspond to the airbag array in an integer multiple relationship. S4. Process the pressure distribution matrix to identify the location of the target airbag where the local peak pressure is located and the set of adjacent surrounding airbags corresponding to the target airbag. S5. When the peak pressure exceeds the preset safety threshold and the time since the last active decompression action reaches the time interval T, control the target airbag to depressurize through the corresponding solenoid valve, and at the same time control the surrounding airbags to inflate and pressurize, so that the pressure is redistributed to the surrounding area. S6. Repeat steps S3 to S5 to achieve periodic active pressure equalization and fixed-point pressure reduction.

[0009] Furthermore, the identification of the target airbag location where the local peak pressure is located in step S4 includes taking the average pressure or maximum pressure value of the k×k pressure sensing units covered by each airbag as the equivalent pressure value of the airbag, and taking the airbag number where the maximum equivalent pressure value of all airbags is located as the target airbag location.

[0010] Furthermore, the surrounding airbag set is defined as adjacent airbags located in the same row or column as the target airbag and spaced no more than d airbag units apart. Here, d is a natural number, which can be determined based on the specific circumstances, for example, it can be 4.

[0011] Furthermore, in step S5, the pressure value of the target airbag after depressurization is controlled to be no higher than 1.2 times the average pressure of the surrounding airbag assembly, and no lower than the minimum support pressure limit of the air cushion, in order to avoid slippage and excessive sinking.

[0012] Furthermore, the method includes step S0: obtaining the user's physical parameters, wherein the physical parameters are the body mass index (BMI) value, and selecting a polyurethane airbag assembly with corresponding Shore hardness from a preset BMI-airbag material hardness mapping table for installation based on the BMI value; the mapping table includes at least multiple hardness gradients for soft airbags with Shore A 30°±5° corresponding to BMI≤16 and hard airbags with Shore A 85°~90° corresponding to BMI≥32.

[0013] Beneficial effects Compared with existing technologies, this invention abandons the traditional crude control mode of overall pressure equalization or fixed-cycle alternating inflation. It constructs a pressure distribution matrix in real time through a high-resolution flexible pressure sensor array, uses algorithms to accurately identify local peak pressure points (extreme points), and adopts a differentiated adjustment strategy of targeted deflation of high-pressure balloons and coordinated inflation of neighboring balloons. This fundamentally eliminates the risk of capillary occlusion and achieves truly proactive and precise pressure ulcer prevention.

[0014] By incorporating clinically established BMI physical parameters and the Braden pressure ulcer risk assessment scale into the air cushion control system, and matching airbag materials with different Shore hardness based on BMI values, the system effectively solves the problems of "digging pain" in thin individuals and "sinking shearing" in obese individuals. By setting differentiated decompression cycles through Braden scores, it ensures that extremely high-risk patients receive frequent and sufficient decompression while avoiding unnecessary noise and energy consumption interference for low-risk patients. This "tailor-made" personalized adaptation mechanism allows the invention to meet the pressure ulcer prevention needs of users across the entire spectrum, from low-risk to extremely high-risk, and from thin to obese.

[0015] On the other hand, the present invention provides an anti-pressure sore airbag cushion system, comprising: An air cushion base has multiple airbag mounting slots arranged in an array on it. The interior of the air cushion base is integrally formed with embedded pneumatic channels. One end of each embedded pneumatic channel is connected to the bottom air port of the corresponding airbag mounting slot, and the other end is gathered at the confluence interface on the side of the air cushion base. Multiple independent airbags are respectively installed in the airbag mounting slots and connected to the embedded pneumatic flow channel through the bottom air port; A flexible pressure sensor array is laid on the bearing surface above the independent airbag to collect the pressure distribution matrix; The air circuit control module includes an air pump, a main reversing solenoid valve, and multiple independently controlled airbag solenoid valves, wherein the airbag solenoid valves are connected to the manifold interface via external air pipes. The controller is electrically connected to the flexible pressure sensor array and the air circuit control module, respectively, and is used to execute the steps of the air cushion pressure control method described in any of the above schemes.

[0016] Furthermore, each airbag in the airbag array corresponds to at least 2×2 pressure sensing pixels; the air cushion base is integrally formed by 3D printing, and the embedded pneumatic flow channel has a circular or elliptical cross section with a smooth inner wall transition.

[0017] Furthermore, the independent airbag has a retractable foldable wall and a dovetail-shaped mounting lip, which snaps into the airbag mounting groove and forms an interference seal; the system also includes a removable and washable breathable airbag cover, which is fitted over the airbag base and the outside of the airbag assembly.

[0018] In another aspect, the present invention provides an air cushion substrate, comprising: The substrate has an upper surface; Multiple airbag mounting slots are arrayed on the upper surface of the substrate to position and accommodate individual airbags; An embedded pneumatic flow channel network is formed inside the substrate. Each embedded pneumatic flow channel extends downward from the air hole on the bottom wall of the corresponding airbag mounting groove and converges in the substrate. The terminal opening is formed at the side of the substrate to form a confluence interface. The substrate is integrally formed by additive manufacturing process, and the embedded pneumatic flow channel network is formed simultaneously during the printing process.

[0019] Furthermore, the embedded pneumatic flow channel network features smooth rounded corner transitions at the branch nodes of the main air channel, with an equivalent diameter between Φ1.5mm and Φ3.0mm. Due to the regular cross-section and smooth corners of the airflow channels, airflow resistance is low. Combined with an efficient extreme value recognition algorithm, the system can quickly respond to pressure changes. In low-risk mode, extending the decompression cycle significantly reduces the frequency of air pump start-up and shutdown, extending the battery life on a single charge to over 8 hours, while also effectively reducing operating noise and improving user comfort during extended use.

[0020] Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: The highly integrated structure significantly improves reliability. By using 3D printing technology to embed complex pneumatic tubing into the air cushion base and form it as a single piece, the airtightness and long-term reliability of the system are greatly improved. At the same time, the overall thickness of the air cushion is compressed to less than 35mm, making the structure more compact and lightweight, and significantly reducing assembly and maintenance costs. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A perspective view of an application scenario for an anti-pressure sore airbag cushion system provided in an embodiment of the present invention; Figure 2 for Figure 1 The diagram shows a three-dimensional view of the pressure ulcer prevention airbag cushion system. Figure 3 for Figure 2 The main view; Figure 4 for Figure 2 Three-dimensional view of the internal structure of the gas path control module; Figure 5 for Figure 4 The diagram shows a manifold and multiple airbag solenoid valves in the air circuit control module. Figure 6for Figure 5 A partial sectional view of the structure from below; Figure 7 for Figure 2 A three-dimensional perspective view of the air cushion base; Figure 8 for Figure 2 A cross-sectional perspective view of a single airbag in the central airbag assembly; Figure 9 This is a schematic diagram of an anti-pressure sore airbag cushion system provided in an embodiment of the present invention; Figure 10 Pressure analysis diagram of the airbag assembly before adjustment during use in one embodiment of the pressure ulcer prevention airbag system provided by the present invention; Figure 11 In order to be in Figure 10 The pressure analysis diagram is based on the adjustment of the airbag assembly. Figure 12 In another embodiment of the pressure ulcer prevention airbag cushion system provided in this invention, a pressure analysis diagram is shown before the airbag assembly is adjusted during use. Figure 13 In order to be in Figure 12 The pressure analysis diagram is based on the adjustment of the airbag assembly.

[0023] Explanation of reference numerals in the attached figures 100. Air cushion base; 110. Airbag mounting groove; 111. Air hole; 120. Embedded pneumatic flow channel; 130. Manifold interface; 140. Air cushion outer sleeve; 200. Airbag assembly; 210. Independent airbag; 211. Corrugated sidewall; 212. Lip edge; 300. Sensor array; 400. Air circuit control module; 410. Air pump; 420. Main reversing solenoid valve; 430. Relay module; 431. Relay; 440. Airbag solenoid valve; 450. Manifold; 451. First air port; 452. Second air port; 453. Third air port; 500. Central controller. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] Most existing pressure ulcer prevention air cushions are passive, offering limited protection against pressure ulcers and failing to provide precise or on-demand pressure relief. Passive pressure ulcer prevention air cushions work by increasing the local contact area. When a person sits on the air cushion, the pressure from the buttocks creates a local depression, increasing the local contact area. This helps alleviate the pressure (interface pressure) on a unit area at bony prominences such as the ischium and sacrum, thereby dispersing pressure and reducing the risk of pressure ulcers. However, the extent to which this type of air cushion increases the local contact area is limited, thus limiting its effectiveness in preventing pressure ulcers and preventing precise or on-demand pressure relief.

[0029] Existing intelligent pressure ulcer prevention airbag cushions are categorized into coarse-zone airbag cushions and fine-zone airbag cushions based on their airbag zoning. Coarse-zone airbag cushions have overly coarse zoning, while fine-zone airbag cushions have numerous independent pneumatic connectors and pneumatic tubing components, resulting in a complex structure. To avoid complex mechanical structures, coarse-zone airbag cushions simply divide the cushion into two areas (left and right) or, based on the left and right zoning, further divide it into four areas (front and back). The coarse zoning of coarse-zone airbag cushions results in excessively large coverage areas for individual airbags, failing to adapt to the subtle contour differences of key areas such as the ischial tuberosities and sacrum. For wheelchair users with uneven weight distribution (such as hemiplegia or scoliosis), coarse zoning cannot specifically alleviate high-pressure points, still posing a risk of pressure ulcers. Fine-zone airbag cushions are mostly array-type (6×6 or 8×8) airbag cushions with complex base structures and numerous internal pneumatic connectors and pneumatic tubing, increasing the risk of air leakage and reducing system reliability. The fine-grained partitioned airbag cushion (8×8 array airbag cushion) involved in this invention embeds the pneumatic pipeline inside the airbag base structure, which greatly reduces the number of independent pneumatic joints and pneumatic pipeline components inside the airbag base. While simplifying the mechanical structure and reducing the risk of air leakage, it also increases the reliability of the system.

[0030] Most existing pressure ulcer prevention air cushions are made of specific materials, and the firmness of the support material often cannot be personalized to the user's body parameters. If the support material is too firm, bony prominences such as the ischium and sacrum will experience greater interfacial pressure, resulting in poor pressure relief and pressure equalization. If the support material is too soft, users sitting on the air cushion will find it difficult to stay still, as if sitting on a "ball," and their buttocks are prone to uncontrollable sliding. On the one hand, when sliding, friction and shear forces are generated between the buttocks and the air cushion surface. This shear force is an important mechanical factor leading to pressure ulcer formation, sometimes even more harmful than vertical pressure. On the other hand, sliding makes it difficult to maintain a normal sitting posture. To counteract sliding, users are prone to adopting incorrect compensatory postures (such as excessive forward, lateral, or backward tilting of the spine), which may lead to complications such as muscle pain, joint damage, or scoliosis over time.

[0031] Current intelligent pressure ulcer prevention airbag cushions use a universal control method with a fixed airbag adjustment cycle, which cannot be personalized to suit the user's pressure ulcer risk level. If the airbag adjustment cycle is too long, the pressure ulcer prevention effect is poor; if the adjustment cycle is too short, the air pump 410 starts frequently, generating frequent noise, high energy consumption, and shortening the lifespan of components. Clinically, different users have different physical conditions and pressure ulcer risks. Therefore, a personalized airbag adjustment mechanism is beneficial for reducing noise, improving user comfort, and ensuring adequate pressure relief and equalization to achieve a good pressure ulcer prevention effect.

[0032] Example 1: See Figures 1 to 8 This embodiment provides an anti-pressure ulcer airbag cushion system, suitable for applications such as wheelchairs and nursing beds. The system mainly consists of an airbag base 100, an airbag assembly 200, a flexible pressure sensor array 300, an air path control module 400, and a central controller 500.

[0033] The air cushion base 100 is integrally formed using photosensitive resin (such as SLA 9400 resin) or nylon material (PA12) through selective laser sintering (SLS) or photopolymerization 3D printing. The upper surface of the air cushion base 100 can be contoured to conform to the physiological curves of the human buttocks and posterior thighs, and has 64 airbag mounting slots 110 arranged in an array of 8 rows × 8 columns. Each airbag mounting slot 110 has an air hole 111 at the center of its bottom surface, which extends downward and connects to an embedded pneumatic flow channel 120 formed inside the air cushion base 100. The embedded pneumatic flow channels 120 are distributed in a tree-like or mesh-like pattern inside the air cushion base 100, with each branch channel ending at a bottom air hole 111 of an airbag mounting slot 110, and the main flow channels converging at the side of the air cushion base 100 to form a confluence interface 130. The embedded pneumatic channel 120 has a circular cross-section, preferably with a diameter of Φ2.0mm to Φ2.5mm. All corners of the channel are smoothly transitioned with a radius of R≥2mm to reduce airflow resistance and prevent substrate cracking due to stress concentration. The 3D-printed, one-piece embedded pneumatic channel 120 significantly reduces the risk of air leakage and compresses the overall thickness of the air cushion to less than 35mm.

[0034] The airbag assembly 200 comprises 64 individual airbags 210. Each individual airbag 210 is cast from polyurethane elastomer and features retractable, foldable corrugated sidewalls 211 and a dovetail-shaped mounting lip 212 at the bottom. During installation, the dovetail-shaped mounting lip 212 is inserted into the edge groove of the airbag mounting recess 110, forming an interference fit and radial seal. Airtightness is then ensured by bonding. Because the individual airbags 210 employ a dovetail-lip lip 212 snap-fit ​​structure, even if an individual airbag is damaged, it can be individually removed and replaced without discarding the entire airbag system, significantly reducing maintenance costs.

[0035] The top of the independent airbag 210 is a rounded pressure-bearing surface that contacts the human body. As shown in the table below, based on the BMI differences of the target user group, the independent airbag 210 is made of polyurethane resin. Depending on the proportions of the materials used in its manufacture, polyurethane resin can be made into seven different soft textures, specifically including seven different hardness levels: Shore A hardness of 30°, 40°, 50°, 60°, 70°, 80°, and 90°. Referring to the BMI-airbag material hardness mapping table below, for thin users with a BMI ≤ 16, an ultra-soft airbag with Shore A 30° is selected to increase the contact area and fill the gaps between bony prominences; for obese users with a BMI ≥ 32, a hard airbag with Shore A 90° is selected to provide sufficient support rigidity and prevent shear forces caused by excessive sinking.

[0036] BMI – Airbag Material Hardness Mapping Table:

[0037] A flexible pressure sensor array 300 is laid on top of the airbag assembly 200 to sense pressure distribution in real time. In this embodiment, the flexible pressure sensor array 300 uses a 16×16 matrix flexible thin-film pressure sensor with a total of 256 independent sensing units. The size of the sensor array 300 matches the airbag bearing surface, and its sensing units correspond to the 8×8 airbag array below in a 2×2 relationship, that is, every 4 sensing units correspond to the pressure coverage area of ​​one independent airbag 210. The flexible pressure sensor array 300 is led out via an FPC cable and connected to the signal acquisition interface on the side of the airbag.

[0038] Reference Figure 1 As shown, in some embodiments, the air cushion base 100 and the airbag assembly 200 are covered by a removable air cushion cover 140 made of breathable mesh fabric. This cover is zipped or Velcro-fastened for easy removal, washing, and disinfection.

[0039] The airway control module 400 is installed in the accommodating space below the air cushion base 100 or within the wheelchair frame. It includes an air pump 410, a two-position three-way main reversing solenoid valve 420, a relay module 430, and 16 two-position three-way miniature airbag solenoid valves 440. The output of the air pump 410 is connected to the air inlet P of the main reversing solenoid valve 420, and the common port COM of the main reversing solenoid valve 420 is connected to the manifold interface 130 of the air cushion base 100 via a manifold. The air inlets of the 16 two-position three-way miniature airbag solenoid valves 440 are connected in parallel to the main airway, and their outlets are connected via short pipes to the branch ports of the embedded pneumatic flow channel 120 of the air cushion base 100 (or to the corresponding airbag groups via external short pipes). Each two-position three-way miniature airbag solenoid valve 440 is normally closed, maintaining the airbag seal when power is off, and is only energized to operate when it is necessary to adjust the airbag pressure in a certain area. The relay module 430 is controlled by the central controller 500 and is used to drive the on / off of 16 airbag solenoid valves 440, air pump 410, and main reversing solenoid valve 420 in a time-sharing manner.

[0040] It should be noted that the air pump 410 can be a small, silent 12V DC air pump 410, with an adjustable air volume of 3~18L / MIN and a pressure of 95KPa.

[0041] Reference Figure 5 , Figure 6 As shown, in some embodiments, multiple airbag solenoid valves 440 are mounted on a manifold 450. The manifold 450 has a 16-position interface, which is connected to the manifold interface 130 of the air cushion base 100 via an external air tube. The manifold 450 has three air holes 111 corresponding to each interface: a first air hole 451, a second air hole 452, and a third air hole 453. These three air holes 111 communicate with the same airbag solenoid valve 440, allowing the air to be switched on and off. Specifically, the first air hole 451 is connected to the inflation channel, the second air hole 452 is connected to the deflation channel, and the third air hole 453 is connected to an interface. When the first air hole 451 and the third air hole 453 are connected through the airbag solenoid valve 440, the independent airbag 210 is inflated; when the second air hole 452 and the third air hole 453 are connected through the airbag solenoid valve 440, the independent airbag 210 is deflated.

[0042] The central controller 500 uses a 410STM32 series microcontroller as its main control chip. Its pins are connected to the signal output of the flexible pressure sensor array 300, the control terminal of the relay module 430, and the user input panel (including the Braden scoring DIP switch) located on the side of the air cushion. The central controller 500 incorporates an analog-to-digital converter, data processing algorithms, and control logic programs to implement adaptive pressure control. The system is powered by a 12V / 10Ah rechargeable lithium battery pack, installed on the wheelchair floor or in the rear support of the air cushion. Specifically, the rechargeable lithium battery pack can be a 12V battery pack composed of 12 18650 batteries with a capacity of 10000mAh.

[0043] Reference Figure 4 As shown, the relay module 430 includes a relay 431, which is connected to multiple airbag solenoid valves 440 via an RS485 control line, and is used to control the operation of each airbag solenoid valve 440 respectively.

[0044] This embodiment organically combines 3D-printed embedded airway structure, matrix pressure sensing, active fixed-point decompression algorithm based on extreme value recognition, and personalized adaptation strategy based on BMI / Braden score. It solves the technical problems of poor passive decompression effect, complex and easily damaged airway, and inability to be personalized in traditional pressure ulcer prevention air cushions, and significantly improves the reliability, comfort and clinical pressure ulcer prevention effect of the product.

[0045] The airbag adjustment cycle in this invention can be adjusted by modifying the time parameter in the control program. The Braden Pressure Ulcer Risk Assessment Scale (as shown in the table below) is used to determine the airbag adjustment cycle based on the user's pressure ulcer risk level. The Braden Pressure Ulcer Risk Assessment Scale is suitable for adults, children, and other patients at high risk of pressure injuries. It includes six key risk factors (sensory perception, moisture, mobility, locomotion, dietary intake, and friction / shear force), with each factor scored from 1 to 4 points (some dimensions from 1 to 3 points), for a total score range of 6 to 23 points. Lower scores indicate higher risk and a greater likelihood of pressure ulcers. For users with a higher risk of pressure ulcers, a shorter airbag adjustment cycle should be used to ensure adequate pressure ulcer prevention. For users with a lower risk of pressure ulcers, a longer airbag adjustment cycle can be used to reduce noise, lower energy consumption, increase airbag lifespan, and improve airbag comfort.

[0046] Braden Pressure Ulcer Risk Assessment Scale: I. Six assessment dimensions (1-4 points each, total score 6-23 points) 1. Perception ability (1–4 points) 1 point: Completely restricted, no pain perception 2 points: Very limited, only responds to severe pain. 3 points: Mild limitation, dulled pain perception 4 points: No limitations, normal perception of stress discomfort 2. Humidity (1–4 points) 1 point: Persistent dampness, skin is always cold and damp. 2 points: Very damp, sheets need to be changed every shift. 3 stars: Occasionally damp, change once a day 4 points: Very little moisture, skin is basically dry. 3. Activity ability (1–4 points) 1 point: Bedridden and unable to move independently 2 points: Confined to a chair, unable to walk. 3 points: Occasionally walks, requires assistance 4 points: Walks frequently and moves freely. 4. Mobility (1–4 points) 1 point: Completely unable to roll over / move independently 2 points: Only slight movement, unable to adjust independently. 3 points: Can independently make minor adjustments to body position 4 points: Can freely and easily change postures 5. Nutritional status (1–4 points) 1 point: Very poor, prolonged fasting / severe emaciation 2 points: Possibly insufficient; reduced food intake and weight loss. 3 points: Sufficient, normal diet, stable weight 4 points: Excellent, good appetite, and adequate nutrition. 6. Friction and shear force (1–3 points) 1 point: High risk, frequent slips and friction. 2 points: Potential risk, mobile assistance required. 3 points: No obvious risks, smooth movement without dragging. II. Risk Classification (Overall Score Assessment) 19–23 points: No risk 15–18 points: Mild risk, routine prevention. 13–14 points: Moderate risk, increase stress relief by turning the baby over. 10–12 points: High risk, use pressure-reducing pads and specialized care. ≤9 points: Extremely high risk, turn over every 2 hours, special pressure ulcer treatment plan III. Key Points of Use Immediate assessment upon admission / transfer; Critical conditions, post-operative care, and changes in the patient's condition require immediate reassessment. For scores ≤18, implement pressure ulcer prevention measures and record them.

[0047] Example 2: This embodiment details the air cushion pressure control method executed by the central controller 500. The method flow is as follows: Figure 9 As shown, Figure 9 Solid arrows indicate power and electrical signal transmission, while hollow arrows indicate gas source transmission.

[0048] Specifically, the following steps are included: Step S1: Parameter Initialization and Personalized Configuration. After the system is powered on, the caregiver or user enters the user's Braden pressure ulcer risk assessment score via the input panel. The central controller 500 receives this parameter and retrieves the corresponding configuration from the built-in mapping table. For example, referring to the table below: Input Braden score = 10 (extremely high risk), the system locks the active decompression trigger interval T = 20 minutes.

[0049] Braden Score – Active Stress Reduction Cycle Mapping Table:

[0050] Step S2: System pre-inflation. The central controller 500 starts the air pump 410, the main reversing solenoid valve 420 switches to the inflation position, and simultaneously opens all 16 airbag solenoid valves 440 to inflate the 64 independent airbags 210 uniformly until the pressure of each airbag reaches the reference pressure value. After completion, the air pump 410 and solenoid valves are turned off, and the airbags enter the pressure-holding standby state.

[0051] Step S1: Real-time pressure sampling. The central controller 500 reads 256 pressure data from the flexible pressure sensor array 300 at regular intervals (e.g., once per second) to construct a 16×16 pressure distribution matrix P[i][j], where i and j represent row and column indices, respectively.

[0052] Step S2: Pressure Data Processing and Extreme Value Identification. The controller partitions the pressure matrix P[i][j], merging the data from every 2×2 adjacent sensing units to calculate the equivalent pressure value P_k (k=1~64) for the corresponding single independent airbag 210 below. The 64 equivalent pressure values ​​P_k are traversed and compared to find the maximum value P_max and its corresponding target airbag number K_max. Simultaneously, the set of surrounding airbags of the target airbag K_max is determined, defined as four (or fewer, depending on the edge position) adjacent airbags that are in the same row or column as the target airbag and are one unit apart (i.e., immediately adjacent).

[0053] Step S3: Decompression Condition Judgment. The controller determines whether P_max exceeds the preset safety threshold (corresponding to the critical pressure for capillary closure) and whether the set time interval T has elapsed since the last active decompression action. If both conditions are met, proceed to step S4 to perform active fixed-point decompression; otherwise, return to step S1 to continue monitoring.

[0054] Step S4: Active Point-to-Point Pressure Equalization. The controller activates the airbag solenoid valve 440 connected to the target airbag K_max, opening the exhaust passage to release gas from the target airbag K_max and reduce its pressure. Simultaneously, the controller activates the airbag solenoid valve 440 connected to the surrounding airbags, opening the inflation passage and using the air pump 410 to inflate the surrounding airbags, increasing their pressure. During this process, the controller continuously monitors the feedback value of the pressure sensor. When the pressure of the target airbag K_max drops to less than 1.2 times the average pressure of the surrounding airbags, the exhaust and inflation are stopped, and the pressure-holding state is restored. This action effectively releases the excessive pressure originally concentrated at bony prominences (such as the ischial tuberosity) and redistributes it to the surrounding soft tissue areas, achieving true point-to-point pressure release and local pressure equalization.

[0055] Step S5: Periodic Cycle. After completing one active pressure reduction cycle, the system resets the timer, returns to step S1, and continues to monitor and dynamically adjust the pressure according to the set cycle until the system is powered off.

[0056] In actual use, the system runs automatically based on the input Braden parameters, without the need for manual intervention.

[0057] Reference Figure 10 As shown, in one embodiment, the pressure analysis diagram fed back by the sensor array 300 after the user's buttocks and back of the thighs come into contact with the sensor array 300 on the airbag assembly 200 is shown.

[0058] Central controller 500 according to Figure 10 Based on the pressure analysis results, the pressure of the corresponding independent airbags 210 in the airbag assembly 200 was adjusted to obtain... Figure 11 The results of the pressure analysis.

[0059] Reference Figure 12 As shown, in another embodiment, after the user's buttocks and the back of their thighs come into contact with the sensor array 300 on the airbag assembly 200, a pressure analysis graph is obtained from the sensor array 300.

[0060] Central controller 500 according to Figure 12 Based on the pressure analysis results, the pressure of the corresponding independent airbags 210 in the airbag assembly 200 was adjusted to obtain... Figure 13 The results of the pressure analysis.

[0061] As can be seen from the above two embodiments, the pressure ulcer prevention airbag system provided in this embodiment can eliminate the problem of excessive local pressure between the human body and the airbag, thereby achieving truly active and precise pressure ulcer prevention.

[0062] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A method for controlling air cushion pressure, characterized in that, Includes the following steps: S1. Determine the active decompression trigger time interval T of the airbag array; S2. After the system is powered on, the multiple independent airbags (210) arranged in an m×n matrix on the air cushion are pre-inflated to the reference pressure; S3. Collect the pressure distribution matrix under the current usage state. The sensing unit of the pressure distribution matrix corresponds to the airbag array in an integer multiple relationship. S4. Process the pressure distribution matrix to identify the location of the target airbag where the local peak pressure is located and the set of adjacent surrounding airbags corresponding to the target airbag. S5. When the peak pressure exceeds the preset safety threshold and the time since the last active decompression action reaches the time interval T, control the target airbag to depressurize through the corresponding solenoid valve, and at the same time control the surrounding airbags to inflate and pressurize, so that the pressure is redistributed to the surrounding area. S6. Repeat steps S3 to S5 to achieve periodic active pressure equalization and fixed-point pressure reduction.

2. The air cushion pressure control method according to claim 1, characterized in that, The step S4, which identifies the target airbag location where the local peak pressure is located, includes taking the average or maximum pressure value of the k×k pressure sensing units covered by each airbag as the equivalent pressure value of the airbag, and taking the airbag number where the maximum equivalent pressure value of all airbags is located as the target airbag location.

3. The air cushion pressure control method according to claim 2, characterized in that, The surrounding airbag set consists of adjacent airbags located in the same row or column as the target airbag and spaced no more than d airbag units apart.

4. The air cushion pressure control method according to any one of claims 1-3, characterized in that, In step S5, the pressure value of the target airbag after depressurization is controlled to be no higher than 1.2 times the average pressure of the surrounding airbag assembly, and no lower than the minimum support pressure limit of the air cushion, in order to avoid slippage and excessive sinking.

5. The air cushion pressure control method according to any one of claims 1-3, characterized in that, The method also includes step S0: obtaining the user's physical parameters, wherein the physical parameters are the body mass index (BMI) value, and selecting a polyurethane airbag assembly with corresponding Shore hardness from a preset BMI-airbag material hardness mapping table for installation based on the BMI value; the mapping table includes at least multiple hardness gradients, such as soft airbags with Shore A 30°±5° corresponding to BMI≤16 and hard airbags with Shore A 85°~90° corresponding to BMI≥32.

6. A pressure ulcer prevention airbag cushion system, characterized in that, include: An air cushion base (100) has multiple airbag mounting slots arranged in an array on it. An embedded pneumatic flow channel (120) is integrally formed inside the air cushion base (100). One end of each embedded pneumatic flow channel (120) is connected to the bottom air port of the corresponding airbag mounting slot, and the other end is gathered at the confluence interface (130) on the side of the air cushion base (100). Multiple independent airbags (210) are respectively installed in the airbag mounting slot and connected to the embedded pneumatic flow channel (120) through the bottom air port; A flexible pressure sensor array (300) is laid on the bearing surface above the independent airbag (210) to collect the pressure distribution matrix; The air circuit control module (400) includes an air pump (410), a main reversing solenoid valve (420) and multiple independently controlled airbag solenoid valves (440), wherein the airbag solenoid valves (440) are connected to the manifold interface (130) via an external air pipe. The controller is electrically connected to the flexible pressure sensor array (300) and the air circuit control module (400) respectively, and is used to execute the steps of the air cushion pressure control method according to any one of claims 1 to 5.

7. The pressure ulcer prevention airbag cushion system according to claim 6, characterized in that, Each airbag in the airbag array corresponds to at least 2×2 pressure sensing pixels; the air cushion base (100) is integrally formed by 3D printing, and the embedded pneumatic flow channel (120) has a circular or elliptical cross section and a smooth inner wall transition.

8. The pressure ulcer prevention airbag cushion system according to claim 6 or 7, characterized in that, The independent airbag (210) has a retractable foldable wall and a dovetail mounting lip (212), which snaps into the airbag mounting groove and forms an interference seal; the system also includes a removable and washable breathable airbag cover (140), which is fitted over the airbag base (100) and the airbag assembly (200).

9. A cushion base, applied to the pressure ulcer prevention airbag cushion system according to any one of claims 6 to 8, characterized in that, include: The substrate has an upper surface; Multiple airbag mounting slots (110) are arrayed on the upper surface of the substrate for positioning and accommodating individual airbags (210). An embedded pneumatic flow channel network is formed inside the substrate. Each embedded pneumatic flow channel extends downward from the air hole (111) on the bottom wall of the corresponding airbag mounting groove (110) and converges in the substrate. The terminal opening is formed at the side of the substrate to form a confluence interface (130). The substrate is integrally formed by additive manufacturing process, and the embedded pneumatic flow channel network is formed simultaneously during the printing process.

10. The air cushion substrate according to claim 9, characterized in that, The embedded pneumatic flow channel network has a smooth rounded corner transition at the branch node of the main air channel, and the equivalent diameter of the flow channel is between Φ1.5mm and Φ3.0mm.

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