Bed body posture adjustment control method

Abstract

The invention discloses a bed body posture adjustment control method, and relates to the field of pressure sore prevention sickbeds. The method comprises the following steps: determining a pressure concentration point by monitoring pressure values of pressure points of a bed body and keeping time thereof in real time, further determining a target area, and calculating the adjustment amount of each regulator by using the distance from the pressure concentration point to a central point of the bed body and a preset scale factor based on the target area, so as to determine the pressure transfer amplitude; a motor control current is generated based on a calculation result, the three regulators are driven to accurately move to expected positions, and real-time correction is performed through a closed-loop feedback system to ensure that each regulator accurately reaches a preset position; according to the method, the plane of the sickbed can form a tiny inclination angle, the pressure distribution of contact between the body of a patient and the bed surface is dynamically changed, the pressure of all parts of the whole body is effectively dispersed, local pressure concentration and long-time compression are avoided, and the risk of pressure sores is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the field of pressure ulcer prevention hospital beds, and particularly to a method for controlling the attitude adjustment of a bed body. Background Art

[0002] Due to impaired brain function, stroke patients may need to stay in bed for a long time after the onset of the disease, and most patients will lose the ability of independent movement. During the period of staying in bed, because some parts of the body are unevenly stressed, pressure ulcers are likely to occur. Pressure ulcers are local injuries caused by continuous pressure or the combination of pressure and shear force acting on the skin and its underlying tissues. In order to prevent pressure ulcers, there are usually specially designed pressure ulcer prevention measures on hospital beds, but these measures are often limited to local protection and it is difficult to comprehensively adjust the pressure on all areas where the patient contacts the bed surface, thus it is difficult to prevent the occurrence of pressure ulcers. Summary of the Invention

[0003] In order to comprehensively adjust the pressure on all areas where the patient contacts the bed surface, the present invention proposes a method for controlling the attitude adjustment of a bed body, which is applied to a pressure ulcer prevention hospital bed. The pressure ulcer prevention hospital bed includes: a bottom plate, on which a control cabinet is provided; a bed body, which is movably arranged above the bottom plate, and on the bottom plate, a first regulator, a second regulator and a third regulator for adjusting the attitude of the bed body are provided, and the first regulator, the second regulator and the third regulator are all electrically connected to the control cabinet; a plurality of pressure sensors are arranged in a rectangular array form on the bed body, and each pressure sensor is electrically connected to the control cabinet; the control method includes the following steps executed by the control cabinet:

[0004] Based on the installation positions of the first regulator, the second regulator and the third regulator, the bed surface is divided into multiple areas; the pressure values of each pressure point on the bed body are obtained in real time through the arranged pressure sensors;

[0005] Based on the pressure values of each pressure point on the bed body and the pressure holding time of each pressure point, the pressure concentration points are determined, the area where the pressure concentration points are located is set as the target area, and based on the target area, the adjustment amount corresponding to each regulator is calculated by using the distance from the pressure concentration point to the center point of the bed body and a preset proportionality factor; the preset proportionality factor is used to determine the pressure transfer amplitude;

[0006] According to the calculated desired stroke of each regulator, that is, the adjustment amount, the motor control current required for each regulator is determined, and a corresponding current command is sent to drive each regulator to move. The actual stroke of each regulator is monitored in real time. For each regulator, through the difference between its actual stroke and the desired stroke, the motor control current is continuously adjusted by using the closed-loop feedback system arranged in the control cabinet, so that each regulator accurately rises and falls to the predetermined position corresponding to the desired stroke.

[0007] Further, the first regulator, the second regulator, and the third regulator are respectively arranged on the first straight line, the second straight line, and the third straight line;

[0008] The first straight line and the second straight line are respectively the connecting lines from the center point of the bed body to two vertices at one end (the head) of the bed body; the third straight line is the perpendicular connecting line from the center point of the bed body to the midpoint of the other end (the foot) of the bed body;

[0009] The first regulator and the second regulator are symmetrically distributed along the center line in the length direction of the bed body.

[0010] Further, based on the installation positions of the first regulator, the second regulator, and the third regulator, the bed body is divided into multiple areas, specifically: the bed body is divided into a first area, a second area, and a third area by the first straight line, the second straight line, and the third straight line; the first area is the area formed by the first straight line, the second straight line, and the edge of the bed body; the second area is the area formed by the first straight line, the third straight line, and the edge of the bed body; the third area is the area formed by the second straight line, the third straight line, and the edge of the bed body.

[0011] Further, the pressure holding duration represents the duration during which the pressure value corresponding to the pressure point continuously exceeds the set pressure threshold; based on the pressure values of each pressure point on the bed body and the pressure holding durations of each pressure point, the pressure concentration points are determined, specifically including:

[0012] Judge whether there are pressure points whose pressure values exceed the set pressure threshold. If so, judge whether there are over-standard points among these pressure points. If so, calculate the coordinates of the pressure concentration points through the pressure values of the over-standard points; the over-standard points refer to the pressure points whose pressure holding duration is greater than the set time threshold.

[0013] Further, based on the target area, the adjustment amounts corresponding to each regulator are calculated by using the distance from the pressure concentration point to the center point of the bed body and the preset proportionality factor, specifically:

[0014] When the target area is the first area, the adjustment amounts corresponding to the first regulator, the second regulator, and the third regulator are set as: +Δh, +Δh, -Δh;

[0015] When the target area is the second area, the adjustment amounts corresponding to the first regulator, the second regulator, and the third regulator are set as: +Δh, -Δh, +λΔh;

[0016] When the target area is the third area, the adjustment amounts corresponding to the first regulator, the second regulator, and the third regulator are set as: -Δh, +Δh, +λΔh;

[0017] Define the length direction of the bed body as the x-axis. Among them, one end of the bed body (the head of the bed) is located on the negative semi-axis, and the other end of the bed body (the foot of the bed) is located on the positive semi-axis; define the width direction of the bed body as the y-axis, where the left side of the bed is set as the negative semi-axis and the right side is set as the positive semi-axis; the origin O is the center point of the bed body;

[0018] Where: Δh = k P l PO ;

[0019] In the formula, k p is the preset proportionality factor, l PO is the distance from the pressure concentration point P to the center point O of the bed body; λ represents the fine-tuning factor (the value range is (-0.5, 0.5)), P x represents the x-axis coordinate of the pressure concentration point P, and H represents the length of the bed body.

[0020] Furthermore, calculating the coordinates of the pressure concentration point through the pressure values of the exceeding-standard points specifically includes:

[0021] Normalize the pressure values of each exceeding-standard point;

[0022] The normalization formula is: In the formula, p min , p max respectively represent the minimum pressure value and the maximum pressure value in the exceeding-standard points; p i represents the pressure value of the i-th exceeding-standard point, and p i ′ represents the normalized pressure value;

[0023] Set corresponding weights for each area, and assign the weight of the area where the exceeding-standard point is located to the exceeding-standard point;

[0024] Based on the coordinates of all exceeding-standard points and their corresponding weights, calculate the coordinates of the pressure concentration point. The calculation formula includes:

[0025] In the formula, n represents the number of exceeding-standard points, x i , y i respectively represent the abscissa and ordinate of the i-th exceeding-standard point, and w i represents the weight of the i-th exceeding-standard point; P x , P y respectively represent the abscissa and ordinate of the pressure concentration point P.

[0026] Furthermore, the top of the first regulator is connected with an adjusting plate, which is connected with the bottom surface of the bed body, and the tops of the second regulator and the third regulator are both connected with the adjusting plate;

[0027] The first regulator, the second regulator, or the third regulator all includes an electric push rod hinged to the bottom plate at one end. An adaptor is movably installed at the other end of the electric push rod. The adaptor can move relative to the electric push rod, and each adaptor is connected to the adjusting plate.

[0028] Further, a bottom connecting block for installing the electric push rod is provided on the bottom plate, and the bottom connecting block and the electric push rod are connected by a third rotating shaft;

[0029] There is a first included angle between the extension line of the third rotating shaft of the first regulator and the extension line of the third rotating shaft of the second regulator; there is a second included angle between the extension line of the third rotating shaft of the first regulator and the extension line of the third rotating shaft of the third regulator; there is a third included angle between the extension line of the third rotating shaft of the second regulator and the extension line of the third rotating shaft of the third regulator. Among them, the first included angle, the second included angle, and the third included angle are all the same and are all 60°;

[0030] The adaptor of the third regulator is located on the center line in the length direction of the adjusting plate, and the adaptors of the first regulator and the second regulator are respectively located on both sides of this center line;

[0031] The adaptors of the first regulator and the second regulator are symmetric with respect to this center line.

[0032] Further, a lifting rod for connecting the adaptor is movably installed on the electric push rod;

[0033] Each adaptor includes an adapter plate movably connected to the top end of the lifting rod, and a top connecting block is rotatably connected to the adapter plate;

[0034] Both ends of the adapter plate are hinged to the lifting rod by a first rotating shaft. A second rotating shaft for movably connecting the top connecting block is provided on the adapter plate, and the first rotating shaft and the second rotating shaft are perpendicular to each other;

[0035] Each first rotating shaft is parallel to the central axis in the length direction of the adjusting plate, and each second rotating shaft is perpendicular to the central axis in the length direction of the adjusting plate.

[0036] Further, each regulator is equipped with a corresponding closed-loop feedback system; the closed-loop feedback system includes:

[0037] An electric cylinder displacement sensor for monitoring the real-time displacement, i.e., the actual stroke, of the lifting rod in the corresponding regulator;

[0038] A first calculation module for calculating the difference between the current actual stroke and the corresponding expected stroke and outputting the difference signal;

[0039] A feedforward compensation module for determining the motor control current required for the corresponding regulator according to the expected stroke;

[0040] A PD controller, configured to convert the difference signal output by the first calculation module into a current adjustment value and output it;

[0041] A second calculation module, configured to add the motor control current calculated by the feedforward compensation module and the current adjustment value calculated by the PD controller to obtain the motor control current for the current wheel adjustment;

[0042] The control cabinet further includes a control module, which is configured to control the operation of the lifting rod in the corresponding regulator according to the motor control current output by the second calculation module.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] (1) By real-time monitoring the pressure values and their holding durations at each pressure point on the bed body, the present invention determines the pressure concentration points, and then determines the target area. Based on the target area, the adjustment amount of each regulator is calculated using the distance from the pressure concentration point to the center point of the bed body and a preset proportional factor, thereby determining the pressure transfer amplitude; a motor control current is generated based on the calculation result to drive the three regulators to accurately move to the desired positions, and real-time correction is performed through a closed-loop feedback system to ensure that each regulator accurately reaches the predetermined position; this method enables the hospital bed plane to form a small tilt angle, dynamically changes the pressure distribution between the patient's body and the bed surface, effectively disperses the pressure on all parts of the body, avoids local pressure concentration and long-term compression, significantly reduces the risk of pressure ulcers, simplifies the complexity of the control system, and improves the stability and nursing efficiency of the system; this not only realizes automated and precise pressure management, but also improves the patient's comfort and nursing quality.

[0045] (2) In the present invention, the first straight line and the second straight line are respectively the connecting lines from the center point of the bed body to the two vertices at one end (the head) of the bed body; the third straight line is the vertical connecting line from the center point of the bed body to the midpoint at the other end (the foot) of the bed body, and the first regulator, the second regulator, and the third regulator are respectively arranged on the first straight line, the second straight line, and the third straight line, and the first regulator and the second regulator are symmetrically distributed along the center line in the length direction of the bed body; that is, the present invention ensures good attitude stability of the hospital bed in any state based on the design principle of determining a plane with three points, reducing the possibility of faults such as jamming caused by a complex mechanical structure.

[0046] (3) The present invention divides the bed body into a first area, a second area, and a third area by the first straight line, the second straight line, and the third straight line; for different target areas, the corresponding adjustment values of each regulator are different, so as to achieve precise adjustment for pressure concentration in a specific area; this zoning processing method improves the efficiency and accuracy of pressure dispersion. In addition, the present invention performs dynamic adjustment based on the real-time monitored pressure value to ensure that the patient can obtain the best pressure distribution in any lying state, effectively preventing the occurrence of pressure sores and improving the nursing quality and patient comfort; this method combines the advantages of zoning precise control and automatic feedback adjustment, providing a more scientific and effective rehabilitation nursing solution for long-term bedridden patients;

[0047] (4) The present invention can precisely control the posture of the hospital bed by using three electric push rods, simplifies the original complex multi-degree-of-freedom control system to three degrees of freedom, reduces the complexity and failure rate, and also reduces the maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic structural diagram of a preferred embodiment of the present invention;

[0049] Figure 2 is Figure 1 an exploded view of

[0050] Figure 3 is an arrangement diagram of the first regulator, the second regulator, and the third regulator on the bottom plate;

[0051] Figure 4 is a schematic structural diagram of the third regulator;

[0052] Figure 5 is a flowchart of a method for adjusting and controlling the posture of a bed body in an embodiment of the present invention;

[0053] Figure 6 is a module structure diagram of a closed-loop feedback system in an embodiment of the present invention;

[0054] Figure 7 is a zoning schematic diagram of an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The following are specific embodiments of the present invention in combination with the accompanying drawings, and the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0056] Embodiment 1

[0057] Existing pressure ulcer prevention hospital beds have several significant problems:

[0058] First of all, most of these hospital beds adopt local protection designs. Whether it is the local bed board flipping type or the multi-airbag type design, there are pressure ulcer protection blind spots, and it is difficult to comprehensively adjust the pressure on all areas where the bedridden patients contact the bed surface, resulting in limited effect of preventing bedsore.

[0059] Secondly, the mechanism design of the bedsore prevention hospital bed is complex and has a large number of control degrees of freedom, making the bed body bulky and prone to faults such as jamming, which affects daily use; especially the multi-airbag type design requires a complex air pressure drive system, further increasing the complexity of the system and the control difficulty.

[0060] Thirdly, there is a lack of real-time monitoring and early warning mechanism for the bedsore situation of patients in bed. The existing hospital beds mainly rely on the experience judgment of medical staff. However, due to the large number of patients in the ward, it is difficult for medical staff to observe the situation of each patient in a timely manner, and it is easy to miss the best opportunity for bedsore prevention.

[0061] Finally, the operation of the bedsore prevention hospital bed is complex and lacks an automatic adjustment function. Usually, medical staff or patient families need to manually adjust according to experience, lacking objective quantitative data support, resulting in randomness in the adjustment timing and operation, making the bedsore protection effect unreliable. These problems together lead to the limitations and inefficiencies of the existing bedsore prevention hospital beds in practical applications.

[0062] Thus, in order to solve the above technical problems, dynamically change the pressure distribution of the patient's body in contact with the bed surface, effectively disperse the pressure on all parts of the body, avoid local pressure concentration and long-term compression, and reduce the risk of pressure ulcers. As Figure 5 shown, the present invention proposes a method for controlling the attitude adjustment of the bed body, which is applied to the bedsore prevention hospital bed, as Figure 1 — Figure 4As shown in the figure, the bedsore prevention hospital bed includes: a bottom plate 100, on which a control cabinet 110 is provided; a bed body 500, which is movably arranged above the bottom plate 100. On the bottom plate 100, a first adjuster 200, a second adjuster 300, and a third adjuster 400 for adjusting the posture of the bed body are provided. The first adjuster 200, the second adjuster 300, and the third adjuster 400 are all electrically connected to the control cabinet 110. A plurality of pressure sensors 510 are arranged in a rectangular array on the bed body 500, and each pressure sensor 510 is electrically connected to the control cabinet 110. When a patient lies on the bed body 500, each pressure sensor 510 reads the pressure of the patient on the bed body 500 at all times and generates corresponding electrical signals to be transmitted to the control cabinet 110. The control cabinet 110 controls the first adjuster 200, the second adjuster 300, and the third adjuster 400 to perform corresponding actions according to the electrical signals generated by each pressure sensor 510, so that the bed body 500 can be flipped in the length direction or in the width direction. In this way, the force of the patient on this part of the bed body 500 can be reduced, and the situation of bedsore on this part of the patient can be avoided.

[0063] In this embodiment, the core controller of the control cabinet 110 uses a Raspberry Pi. The control cabinet collects data of the array pressure sensors through the RS232 communication interface and communicates with the drivers of the electric push rods by using the CAN communication method (the electric push rods and the drivers are in one-to-one correspondence), and respectively controls the three-way electric push rods to execute the stroke adjustment instructions. At the same time, the actual stroke values of the electric push rods are transmitted back through the CAN communication to realize the closed-loop control of the bottom push rod stroke and ensure the adjustment accuracy. In addition, the Raspberry Pi also transmits the posture adjustment information (the height of the lifting rods in each adjuster) and pressure data of the hospital bed to the display via the network cable through the UDP protocol, which is convenient for patients and medical staff to observe the bedsore prevention situation in real time, improving the nursing efficiency and the comfort of the patients. This design not only realizes efficient and accurate pressure management and posture adjustment, but also enhances the visual monitoring ability of the system.

[0064] The first adjuster 200, the second adjuster 300, and the third adjuster 400 are respectively arranged on the first straight line, the second straight line, and the third straight line;

[0065] The first straight line and the second straight line are respectively the connecting lines from the center point of the bed body to the two vertices at one end (the head of the bed) of the bed body 500; the third straight line is the vertical connecting line from the center point of the bed body to the midpoint of the other end (the tail of the bed) of the bed body 500;

[0066] The first adjuster 200 and the second adjuster 300 are symmetrically distributed along the center line in the length direction of the bed body 500.

[0067] The top end of the first regulator 200 is connected to an adjusting plate 600, and the adjusting plate 600 is connected to the bottom surface of the bed body 500. The top ends of the second regulator 300 and the third regulator 400 are both connected to the adjusting plate 600;

[0068] Among them, the central axis of the adjusting plate 600 in the length direction and the central axis of the bed body 500 in the length direction are located in the same vertical plane, and the central axis of the adjusting plate 600 in the width direction and the central axis of the bed body 500 in the width direction are located in the same vertical plane. Thus, when people connect the adjusting plate 600 to the bed body 500 and the first regulator 200, the second regulator 300, and the third regulator 400 adjust the attitude of the adjusting plate 600, the bed body 500 will flip synchronously with the adjusting plate 600 to achieve the center of gravity adjustment of the patient's body by the bed body 500, thereby avoiding excessive pressure concentration and too long pressure concentration time on a certain part of the patient's body.

[0069] The first regulator 200, the second regulator 300, or the third regulator 400 all includes an electric push rod 210 whose one end is hinged to the bottom plate 100. An adaptor 220 is movably installed at the other end of the electric push rod 210. The adaptor 220 can move relative to the electric push rod 210. Each adaptor 220 is connected to the adjusting plate 600. When the control cabinet 110 controls the corresponding electric push rod 210 to work, the electric push rod 210 will drive the corresponding adaptor 220 to lift relative to the electric push rod 210 to change the attitude of the adjusting plate 600.

[0070] A bottom connecting block 211 for installing the electric push rod 210 is provided on the bottom plate 100, and the bottom connecting block 211 and the electric push rod 210 are connected by a third rotating shaft 212;

[0071] There is a first included angle (not marked in the figure) between the extension line of the third rotating shaft 212 of the first regulator 200 and the extension line of the third rotating shaft 212 of the second regulator 300; there is a second included angle (not marked in the figure) between the extension line of the third rotating shaft 212 of the first regulator 200 and the extension line of the third rotating shaft 212 of the third regulator 400; there is a third included angle (not marked in the figure) between the extension line of the third rotating shaft 212 of the second regulator 300 and the extension line of the third rotating shaft 212 of the third regulator 400. Among them, the first included angle, the second included angle, and the third included angle are all the same and are all 60°;

[0072] This precisely designed 60-degree included angle layout not only helps to ensure that the three regulators can act in a coordinated manner when working, but also endows the entire bed body with excellent attitude stability and adaptability. Specifically:

[0073] Posture stability: Since the included angles are the same, no matter what inclination angle or flipping state the bed body 500 is in, the adjusting plate 600 can maintain balance and there is no risk of tipping over. This setting is crucial for maintaining the overall structural stability of the hospital bed.

[0074] Flexibility and precise control: With such a layout, the supporting force in each direction can be adjusted flexibly. When fine posture adjustments are required (such as fine-tuning the pitch angle or roll angle of the bed body 500), this can be achieved by combining the use of these three regulators because the relative position relationship between them allows for a variety of different lifting modes, thus achieving the ideal posture adjustment effect.

[0075] In addition, this design simplifies the mechanical structure, reduces the possibility of jamming or other failures that may be caused by complex mechanical structures. At the same time, it also reduces the maintenance cost, improves the reliability and service life of the bed body.

[0076] The adaptor 220 of the third regulator 400 is located on the center line of the adjusting plate 600 in the length direction, and the adaptors 220 of the first regulator 200 and the second regulator 300 are respectively located on both sides of this center line; the adaptors 220 of the first regulator 200 and the second regulator 300 are symmetric with respect to this center line.

[0077] Specifically, the adaptor 220 of the third regulator 400 is exactly on the central axis of the adjusting plate 600, which enables it to provide the main supporting force and adjustment force in the direction perpendicular to the width of the bed body. This arrangement ensures that when the hospital bed is making a posture adjustment, it can achieve a smooth and symmetric flip with the center line of the adjusting plate 600 as the axis.

[0078] At the same time, the adaptors 220 of the first regulator 200 and the second regulator 300 are designed to be symmetrically arranged on both sides of the adjusting plate 600 with the center line of the adjusting plate 600 as the axis of symmetry. This symmetric layout not only enhances the overall structural stability but also ensures uniform force distribution on both sides, contributing to more precise and balanced posture adjustment. When the first regulator 200 and the second regulator 300 work together, they can precisely control the height changes at both ends of the adjusting plate 600, thereby effectively changing the pitch angle or roll angle of the hospital bed.

[0079] With the above structure, when the first regulator 200 and the second regulator 300 are stationary and the third regulator 400 pushes the adaptor 220 to rise or fall, the adjusting plate 600 and the bed body 500 will flip in the length direction of the bed body 500 to realize the transfer of the contact pressure between the patient and the hospital bed in the front-back direction, that is, to adjust the pitching angle of the hospital bed; when the first regulator 200 is stationary and the second regulator 300 and the third regulator 400 simultaneously push the corresponding adaptors 220 to rise or fall, the adjusting plate 600 and the bed body 500 will flip in the width direction of the bed body 500, and the transfer of pressure in the left-right direction can be realized, that is, to adjust the first roll angle of the hospital bed; similarly, when the second regulator 300 is stationary and the first regulator 200 and the third regulator 400 simultaneously push the corresponding adaptors 220 to rise or fall, the adjusting plate 600 and the bed body 500 will flip in the width direction of the bed body 500, and the transfer of pressure in the left-right direction can be realized, that is, to adjust the second roll angle of the hospital bed.

[0080] Further, through the settings of the first included angle (not marked in the figure), the second included angle (not marked in the figure) and the third included angle (not marked in the figure), it is ensured that the adjusting plate 600 will not topple under the pressure of the bed body 500 in any state, so that the hospital bed has good attitude stability.

[0081] A lifting rod 213 for connecting the adaptor 220 is movably installed on the electric push rod 210; when the electric push rod 210 drives the lifting rod 213 to lift relative to the electric push rod 210, since the lifting rod 213 is connected to the adaptor 220, in this way, the adaptor 220 can be lifted or lowered relative to the electric push rod 210.

[0082] Each adaptor 220 includes an adapter plate 221 movably connected to the top end of the lifting rod 213, and a top connecting block 223 is rotatably connected to the adapter plate 221;

[0083] Both ends of the adapter plate 221 and the lifting rod 213 are hinged by a first rotating shaft 222, and a second rotating shaft 224 for movably connecting the top connecting block 223 is provided on the adapter plate 221, and the first rotating shaft 222 and the second rotating shaft 224 are perpendicular to each other;

[0084] That is to say, the flipping directions of the connecting plate 221 and the top connecting block 223 are perpendicular to each other. Specifically, both ends of the connecting plate 221 are hinged to the lifting rod 213 through the first rotating shaft 222, and a second rotating shaft 224 for movably connecting the top connecting block 223 is provided on the connecting plate 221. In this way, the connecting plate 221 will rotate relative to the lifting rod 213 around the first rotating shaft 222, and the top connecting block 223 will rotate relative to the connecting plate 221 around the second rotating shaft 224. Further, because the first rotating shaft 222 and the second rotating shaft 224 are perpendicular to each other, the flipping directions of the connecting plate 221 and the top connecting block 223 can be perpendicular to each other.

[0085] Each first rotating shaft 222 is parallel to the central axis of the adjusting plate 600 in the length direction, and each second rotating shaft 224 is perpendicular to the central axis of the adjusting plate 600 in the length direction. Therefore, when people adjust the pitch angle or roll angle of the hospital bed, the top connecting block 223 can make an adaptive flip relative to the connecting plate 221. At the same time, the connecting plate 221 can also make an adaptive flip relative to the lifting rod 213, thereby avoiding stress generation between the lifting rod 213 and the adjusting plate 600.

[0086] It should be noted that during the adjustment of the hospital bed posture, only the stroke of the electric push rod is the actively controlled degree of freedom of movement, which is used to push the top surface of the platform to a specific height, while the other three rotational degrees of freedom (rotating around the lower rotating shaft of the electric push rod, the upper first rotating shaft of the electric push rod, and the upper second rotating shaft of the electric push rod respectively) are all passive degrees of freedom of movement. These passive degrees of freedom can adapt to the pitch angle and roll angle posture changes of the top surface of the platform under specific height conditions. Specifically, based on the principle that three points determine a plane, the three electric push rods can accurately determine the posture of a platform by adjusting their respective lengths. The three passive rotational degrees of freedom of each stroke adjustment component can always automatically adapt to and support the formed posture angle, ensuring that the top surface of the platform can smoothly and accurately achieve the required inclination and rotation, thereby providing the best pressure distribution and comfort for patients. This design not only simplifies the complexity of the system but also improves the flexibility and stability of posture adjustment.

[0087] The control method includes the following steps executed by the control cabinet 110:

[0088] As Figure 7 shown, the bed surface is divided into multiple areas based on the installation positions of the first adjuster 200, the second adjuster 300, and the third adjuster 400;

[0089] The bed body 500 is divided into multiple areas based on the installation positions of the first regulator 200, the second regulator 300, and the third regulator 400. Specifically, the bed body 500 is divided into a first area, a second area, and a third area by a first straight line, a second straight line, and a third straight line. The first area is the area formed by the first straight line, the second straight line, and the edge of the bed body 500. The second area is the area formed by the first straight line, the third straight line, and the edge of the bed body 500. The third area is the area formed by the second straight line, the third straight line, and the edge of the bed body 500.

[0090] In the present invention, the bed body is divided into a first area, a second area, and a third area by a first straight line, a second straight line, and a third straight line. For different target areas, the corresponding adjustment amounts of each regulator are different, so as to achieve precise adjustment for pressure concentration in a specific area. This zoning processing method improves the efficiency and accuracy of pressure dispersion. In addition, the present invention performs dynamic adjustment based on the real-time monitored pressure values to ensure that the patient can obtain the best pressure distribution in any lying state, effectively preventing the occurrence of pressure ulcers and improving the nursing quality and patient comfort. This method combines the advantages of zoning precise control and automatic feedback adjustment, providing a more scientific and effective rehabilitation nursing solution for long-term bedridden patients.

[0091] The pressure values of each pressure point on the bed body 500 are obtained in real time through the arranged pressure sensors 510.

[0092] Based on the real-time pressure values of each pressure point on the bed body 500 and the pressure holding duration of each pressure point, the pressure concentration points are determined. The area where the pressure concentration points are located is set as the target area. Based on the target area, the adjustment amount corresponding to each regulator is calculated using the distance from the pressure concentration point to the center point of the bed body and a preset proportionality factor. The preset proportionality factor is used to determine the pressure transfer amplitude.

[0093] The pressure holding duration represents the duration during which the pressure value corresponding to the pressure point continuously exceeds the set pressure threshold. Determining the pressure concentration points based on the pressure values of each pressure point on the bed body 500 and the pressure holding duration of each pressure point specifically includes:

[0094] Judging whether there are pressure points whose pressure values exceed the set pressure threshold. If so, judging whether there are over-standard points among these pressure points. If so, calculating the coordinates of the pressure concentration points through the pressure values of the over-standard points. The over-standard points refer to the pressure points whose pressure holding duration is greater than the set time threshold.

[0095] Calculating the coordinates of the pressure concentration points through the pressure values of the over-standard points specifically is:

[0096] Normalizing the pressure values of each over-standard point.

[0097] The normalization formula is as follows:

[0098] In the formula, p min , p max respectively represent the minimum pressure value and the maximum pressure value among the over-standard points; p i represents the pressure value of the i-th over-standard point, and p i ′ represents the pressure value after normalization;

[0099] Corresponding weights are set for each area, and the weight of the area where the over-standard point is located is assigned to the over-standard point; it should be noted that the sum of the weights of the three areas is equal to 1.

[0100] In the method for adjusting and controlling the posture of the bed body of the present invention, in order to more accurately calculate the pressure concentration points and achieve targeted pressure dispersion adjustment, the concept of setting weights for each area is introduced. This method can assign corresponding weights to the over-standard points (i.e., those pressure points whose pressure values exceed the set threshold and the duration exceeds the set time threshold) according to their specific positions, so as to more accurately determine the pressure concentration points and make effective pressure adjustments accordingly.

[0101] For example, in a specific embodiment, if an over-standard point is located in the first area where pressure sores are likely to occur (assuming that the weight of this area is relatively high), then this over-standard point will be assigned a relatively high weight, indicating that more rapid pressure adjustment is required for this area. On the contrary, if the over-standard point is located in the third area where the risk of pressure sores is relatively low (assuming that the weight of this area is relatively low), then this over-standard point will be assigned a relatively low weight, indicating that although it also needs attention, the urgency and adjustment intensity can be appropriately reduced.

[0102] In this way, not only can the pressure concentration points be more accurately located, but also resources and adjustment strategies can be reasonably allocated according to the actual needs of each area to ensure the formation of an optimized pressure distribution on the entire hospital bed surface and effectively prevent the occurrence of pressure sores. In addition, this weight-based method also improves the flexibility and adaptability of control, enabling it to make personalized adjustments according to the actual conditions of different patients, further improving the nursing quality and patient comfort.

[0103] Based on the coordinates of all over-standard points and their corresponding weights, calculate the coordinates of the pressure concentration points. The calculation formula includes:

[0104]

[0105] In the formula, n represents the number of over-standard points, x i , y i respectively represent the abscissa and ordinate of the i-th over-standard point, wi represents the weight of the i-th over-standard point; P x and P y respectively represent the abscissa and ordinate of the pressure concentration point P.

[0106] The adjustment amount corresponding to each regulator is calculated based on the distance from the pressure concentration point to the center point of the bed body in the target area and a preset proportionality factor, specifically as follows:

[0107] When the target area is the first area, the adjustment amounts corresponding to the first regulator 200, the second regulator 300, and the third regulator 400 are set as: +Δh, +Δh, -Δh;

[0108] When the target area is the second area, the adjustment amounts corresponding to the first regulator 200, the second regulator 300, and the third regulator 400 are set as: +Δh, -Δh, +λΔh;

[0109] When the target area is the third area, the adjustment amounts corresponding to the first regulator 200, the second regulator 300, and the third regulator 400 are set as: -Δh, +Δh, +λΔh;

[0110] Define the length direction of the bed body 500 as the x-axis, where one end (the head of the bed) of the bed body 500 is located on the negative semi-axis, and the other end (the tail of the bed) of the bed body 500 is located on the positive semi-axis; define the width direction of the bed body 500 as the y-axis, where the left side of the bed is set as the negative semi-axis and the right side is set as the positive semi-axis; the origin O is the center point of the bed body;

[0111] where: Δh = k p l PO ;

[0112] In the formula, k p is the preset proportionality factor (set based on experience), l PO is the distance from the pressure concentration point P to the center point O of the bed body; λ represents the fine-tuning factor (the value range is (-0.5, 0.5)), P x represents the x-axis coordinate of the pressure concentration point P, and H represents the length of the bed body.

[0113] According to the calculated expected stroke, i.e., the adjustment amount, of each regulator, determine the motor control current required for each regulator, and send the corresponding current command to drive each regulator to move. Monitor the actual stroke of each regulator in real time. For each regulator, use the difference between its actual stroke and the expected stroke, and continuously adjust the motor control current through the closed-loop feedback system set in the control cabinet 110 to make each regulator accurately lift to the predetermined position corresponding to the expected stroke.

[0114] Each regulator is equipped with a corresponding closed-loop feedback system; the closed-loop feedback system includes:

[0115] An electric cylinder displacement sensor for monitoring the real-time displacement, i.e., the actual stroke, of the lifting rod 213 in the corresponding regulator;

[0116] A first calculation module for calculating the difference between the current actual stroke and the corresponding desired stroke and outputting the difference signal;

[0117] A feedforward compensation module for determining the motor control current required for the corresponding regulator according to the desired stroke;

[0118] Specifically, the required motor control current is calculated through a pre-established dynamic model of the stroke adjustment assembly. In the present invention, the core controller (such as a Raspberry Pi) of the control cabinet uses known dynamic parameters to simulate the operation of the electric push rod under different working conditions, so as to calculate the motor control current required to achieve a specific posture (i.e., the calculated adjustment amount). This preset dynamic model takes into account factors such as the working load and movement resistance of the electric push rod. When the hospital bed needs to be adjusted in posture, the core controller quickly responds based on these pre-calculated results and generates corresponding motor control instructions. This method not only improves the response speed and accuracy of control, but also enhances the overall control stability and efficiency. In addition, the pressure sensor data is collected through the RS232 interface, and the CAN communication method is used to interact with the electric push rod driver, ensuring the realization of real-time monitoring and precise control.

[0119] Among them, the stroke adjustment assembly mainly includes an electric push rod (210), an adjustment plate (600), an adaptor (220), a lifting rod (213), a connecting plate (221), a top connecting block (223), and related rotating shafts (the first rotating shaft 222, the second rotating shaft 224, and the third rotating shaft 212). Among them:

[0120] 1. The electric push rod 210, as the actively controlled degree of freedom of movement, is responsible for pushing the adjustment plate 600 to a specific height, thereby changing the posture of the bed body.

[0121] 2. The adaptor 220 is installed at the top of the electric push rod 210 and connected to the adjustment plate 600, allowing relative movement with respect to the electric push rod 210 to adapt to the posture adjustment requirements.

[0122] 3. The lifting rod 213 is used to connect the adaptor 220 and drive the adjustment plate 600 to change its posture through its up and down movement.

[0123] 4. The connecting plate 221 and the lifting rod 213 are hinged through the first rotating shaft 222, and a second rotating shaft 224 is provided thereon for connecting the top connecting block 223, so that the connecting plate 221 and the top connecting block 223 can rotate in a specific direction, providing additional passive degrees of freedom of movement to adapt to different pitch angle and roll angle attitude adjustments.

[0124] These components work together to ensure that the hospital bed can accurately adjust the height and angle, achieve comprehensive optimization of pressure distribution, and effectively prevent the occurrence of pressure sores.

[0125] A PD controller, configured to convert the difference signal output by the first calculation module into a current adjustment value and output it;

[0126] A second calculation module, configured to add the motor control current calculated by the feedforward compensation module and the current adjustment value calculated by the PD controller to obtain the motor control current for the current wheel adjustment;

[0127] The control cabinet 110 further includes a control module, which is configured to control the driver of the electric push rod in the corresponding regulator according to the motor control current output by the second calculation module, and further control the operation of the lifting rod 213.

[0128] It should be noted that when the difference between the actual stroke detected by the first calculation module and the set desired stroke is within a preset error range (for example, ±0.1 mm or other thresholds set according to specific application requirements), it is considered that this adjustment has been completed. At this time, further adjustment instructions for the electric push rod can be stopped.

[0129] The closed-loop feedback system of this embodiment is as Figure 6 shown:

[0130] 1. Desired stroke calculation: First, calculate the desired stroke of each regulator according to the target adjustment amount (i.e., the adjustment amount).

[0131] 2. Feedforward compensation module: This module receives the desired stroke as input and predicts the required basic motor control current according to a pre-established dynamic model to provide a preliminary current command.

[0132] 3. Electric cylinder displacement sensor: Each regulator is equipped with an electric cylinder displacement sensor, which is used to real-time monitor the actual stroke (actual position) of the lifting rod in the corresponding regulator and feedback this information to the first calculation module.

[0133] 4. First calculation module: Receive data from the electric cylinder displacement sensor, calculate the difference between the current actual stroke and the desired stroke, and output the difference signal.

[0134] 5. PD Controller: Converts the difference signal output by the first calculation module into a current adjustment value. The proportional-derivative (PD) control algorithm is utilized here to quickly respond to error changes and provide an appropriate adjustment signal.

[0135] 6. Second Calculation Module: Adds the basic motor control current provided by the feedforward compensation module to the current adjustment value calculated by the PD controller to obtain the final motor control current.

[0136] 7. Control Module: Controls the actuator of the electric pushrod through the final motor control current output by the second calculation module to control the movement of its lifting rod and achieve precise position adjustment.

[0137] The entire process forms a closed-loop feedback system. By continuously comparing the difference between the actual stroke and the desired stroke and adjusting the motor control current according to the difference, it ensures that each regulator can accurately reach the predetermined position.

[0138] This design not only achieves efficient and stable adjustment of the hospital bed posture but also ensures the response speed and accuracy of the system, thereby effectively preventing the occurrence of pressure ulcers and improving the nursing quality and patient comfort.

[0139] This embodiment also provides a method for controlling the posture adjustment of the bed body, namely a preset cyclic mode: The hospital bed performs cyclic posture adjustment movements under a preset motion cycle to ensure that the contact pressure during the patient's lying can maintain dynamic transfer within each motion cycle, avoiding excessive pressure concentration in a certain area for too long, thereby effectively preventing the occurrence of pressure ulcers. In this mode, key parameters such as the motion cycle and the amplitude of the motion posture (the adjustment amounts corresponding to the first regulator 200, the second regulator 300, and the third regulator 400 respectively) are personalized set by medical staff according to the patient's condition. For example, medical staff can adjust the posture change frequency and amplitude of the hospital bed according to factors such as the patient's weight, health status, and skin sensitivity to achieve the best pressure dispersion effect. This flexible and customizable preset cyclic mode not only improves the nursing efficiency but also enhances the patient's comfort and treatment effect, and is particularly suitable for the rehabilitation care of long-term bedridden patients. In this way, the hospital bed can automatically perform periodic posture adjustments, reducing the workload of medical staff and ensuring that patients can obtain effective pressure ulcer protection at any time period.

[0140] The present invention determines the pressure concentration points by real-time monitoring of the pressure values and their holding durations at each pressure point of the bed body, and then determines the target area. Based on the target area, the adjustment amount of each regulator is calculated using the distance from the pressure concentration point to the center point of the bed body and a preset proportionality factor, thereby determining the pressure transfer amplitude. An electric motor control current is generated based on the calculation result to drive the three regulators to accurately move to the desired positions, and real-time correction is performed through a closed-loop feedback system to ensure that each regulator accurately reaches the predetermined position. This method enables the bed surface to form a small tilt angle, dynamically changes the pressure distribution of the patient's body in contact with the bed surface, effectively disperses the pressure on all parts of the body, avoids local pressure concentration and long-term compression, significantly reduces the risk of pressure ulcers, simplifies the complexity of the control system, and improves the stability and nursing efficiency of the system. This not only realizes automated and precise pressure management but also improves the comfort of the patient and the quality of nursing.

[0141] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the attached drawings). If this specific posture changes, the directional indications will change accordingly.

[0142] In addition, in the present invention, descriptions such as "first", "second", "one", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0143] In the present invention, unless otherwise clearly specified and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0144] In addition, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

Claims

1. A bed posture adjustment control method, characterized in that: The invention is applied to an anti-pressure sore bed, and the anti-pressure sore bed comprises: a bottom plate, a control cabinet is arranged on the bottom plate; a bed body, the bed body is movably arranged above the bottom plate, a first regulator, a second regulator and a third regulator for adjusting the posture of the bed body are arranged on the bottom plate, and the first regulator, the second regulator and the third regulator are all electrically connected to the control cabinet; a plurality of pressure sensors are arranged in a rectangular array on the bed body, and each pressure sensor is electrically connected to the control cabinet; the control method comprises the following steps performed by the control cabinet: The bed surface is divided into a plurality of areas based on the setting positions of the first regulator, the second regulator and the third regulator; the pressure value of each pressure point of the bed body is obtained in real time through the arranged pressure sensors; Based on the pressure values ​​of each pressure point of the bed and the duration of pressure maintenance at each pressure point, the pressure concentration point is determined, and the area where the pressure concentration point is located is set as the target area. Based on the target area, the distance from the pressure concentration point to the center point of the bed and the preset proportional factor are used to calculate the corresponding adjustment amount of each regulator; the preset proportional factor is used to determine the pressure transfer amplitude; Based on the calculated expected stroke, i.e., adjustment amount, of each regulator, the motor control current required for each regulator is determined, and corresponding current instructions are sent to drive each regulator to move, and the actual stroke of each regulator is monitored in real time. For each regulator, the difference between its actual stroke and the expected stroke is used, and the motor control current is continuously adjusted using a closed-loop feedback system installed in the control cabinet, so that each regulator can be accurately raised or lowered to the predetermined position corresponding to the expected stroke.

2. A bed posture adjustment control method according to claim 1, characterized in that: The first regulator, the second regulator and the third regulator are respectively arranged on the first straight line, the second straight line and the third straight line; The first straight line and the second straight line are respectively connecting lines from the center point of the bed to two vertices at one end of the bed; the third straight line is a vertical connecting line from the center point of the bed to the midpoint of the other end of the bed; The first regulator and the second regulator are symmetrically distributed along a center line in the length direction of the bed.

3. A bed posture adjustment control method according to claim 2, characterized in that: The bed is divided into a plurality of areas based on the setting positions of the first adjuster, the second adjuster and the third adjuster, specifically: the bed is divided into a first area, a second area and a third area by a first straight line, a second straight line and a third straight line; the first area is an area formed by the first straight line, the second straight line and the edge of the bed; the second area is an area formed by the first straight line, the third straight line and the edge of the bed; the third area is an area formed by the second straight line, the third straight line and the edge of the bed.

4. A bed posture adjustment control method according to claim 3, characterized in that: The pressure holding time indicates the time period during which the pressure value corresponding to the pressure point is continuously greater than the set pressure threshold; the pressure concentration point is determined based on the pressure value of each pressure point of the bed and the pressure holding time of each pressure point, specifically including: Determine whether there are pressure points whose pressure values ​​exceed the set pressure threshold. If so, determine whether there are any exceeding-standard points among these pressure points. If so, calculate the coordinates of the pressure concentration point according to the pressure values ​​of the exceeding-standard points; the exceeding-standard points represent pressure points whose pressure is maintained for a time longer than the set time threshold.

5. A bed posture adjustment control method according to claim 4, characterized in that: The adjustment amount corresponding to each regulator is calculated based on the target area using the distance from the pressure concentration point to the center point of the bed and the preset proportional factor, specifically: When the target area is the first area, the adjustment amounts corresponding to the first regulator, the second regulator and the third regulator are set to +Δh, +Δh and -Δh respectively; When the target area is the second area, the adjustment amounts corresponding to the first regulator, the second regulator and the third regulator are set to +Δh, -Δh, and +λΔh, respectively; When the target area is the third area, the adjustment amounts corresponding to the first regulator, the second regulator and the third regulator are set to be: -Δh, +Δh, +λΔh respectively; The length direction of the bed is defined as the x-axis, where one end of the bed is located at the negative semi-axis and the other end of the bed is located at the positive semi-axis; the width direction of the bed is defined as the y-axis, where the left side of the bed is set as the negative semi-axis and the right side is set as the positive semi-axis; the origin O is the center point of the bed; Where: Δh = k P l PO ; In the formula, k p is the preset scale factor, l PO is the distance from the pressure concentration point P to the center point O of the bed; λ represents the fine-tuning factor, P x It represents the x-axis coordinate of the pressure concentration point P, and H represents the length of the bed.

6. A bed posture adjustment control method according to claim 5, characterized in that: The coordinates of the pressure concentration point are calculated by the pressure value of the exceeding point, specifically: Normalize the pressure value of each exceeding-standard point; The normalization formula is: In the formula, p min 、p max Respectively represent the minimum pressure value and the maximum pressure value in the exceeding point; p i Indicates the pressure value of the i-th exceeding point, p i ′ Indicates the normalized pressure value; Set a corresponding weight for each area, and assign a weight to the area where the exceeding point is located based on the area where the exceeding point is located; Based on the coordinates of all exceeding points and their corresponding weights, the coordinates of the pressure concentration point are calculated. The calculation formula is include: In the formula, n represents the number of points exceeding the standard, x i ,y i Respectively represent the horizontal and vertical coordinates of the i-th exceeding point, w i represents the weight of the i-th exceeding standard point; P x , P y They respectively represent the horizontal and vertical coordinates of the pressure concentration point P.

7. A bed posture adjustment control method according to claim 1, characterized in that: The top end of the first regulator is connected to an adjustment plate, which is connected to the bottom surface of the bed, and the top ends of the second regulator and the third regulator are both connected to the adjustment plate; The first regulator, the second regulator or the third regulator all include an electric push rod with one end hinged to the base plate, an adaptor is movably mounted on the other end of the electric push rod, the adaptor can move relative to the electric push rod, and each of the adaptors is connected to the adjustment plate.

8. A bed posture adjustment control method according to claim 7, characterized in that: The bottom plate is provided with a bottom connecting block for mounting the electric push rod, and the bottom connecting block is connected to the electric push rod via a third rotating shaft; An extension line of the third rotating shaft of the first regulator and an extension line of the third rotating shaft of the second regulator form a first angle; an extension line of the third rotating shaft of the first regulator and an extension line of the third rotating shaft of the third regulator form a second angle; an extension line of the third rotating shaft of the second regulator and an extension line of the third rotating shaft of the third regulator form a third angle, wherein the first angle, the second angle and the third angle are all the same and are all 60°; The adaptor of the third adjuster is located on the center line of the adjusting plate in the length direction, and the adaptor of the first adjuster and the adaptor of the second adjuster are located on both sides of the center line respectively; The adapting piece of the first adjuster and the adapting piece of the second adjuster are symmetrical about the center line.

9. A bed posture adjustment control method according to claim 7, characterized in that: A lifting rod for connecting the adaptor is movably mounted on the electric push rod; Each of the adaptors comprises a connecting plate movably connected to the top end of the lifting rod, and a top connecting block is rotatably connected to the connecting plate; The two ends of the connecting plate are hinged to the lifting rod through a first rotating shaft, and the connecting plate is provided with a second rotating shaft for movably connecting the top connecting block, and the first rotating shaft and the second rotating shaft are perpendicular to each other; Each first rotating shaft is parallel to the central axis of the adjusting plate in the length direction, and each second rotating shaft is perpendicular to the central axis of the adjusting plate in the length direction.

10. A bed posture adjustment control method according to claim 9, characterized in that: Each regulator is equipped with a corresponding closed-loop feedback system; the closed-loop feedback system includes: The electric cylinder displacement sensor is used to monitor the real-time displacement, i.e. the actual stroke, of the lifting rod in the corresponding regulator; A first calculation module, used for calculating the difference between the current actual stroke and the corresponding expected stroke, and outputting the difference signal; A feed-forward compensation module, used to determine the motor control current required by the corresponding regulator according to the expected stroke; A PD controller, used for converting the difference signal output by the first calculation module into a current adjustment value and outputting the current adjustment value; A second calculation module is used to add the motor control current calculated by the feedforward compensation module and the current adjustment value calculated by the PD controller to obtain the motor control current adjusted by the current wheel; The control cabinet also includes a control module, which is used to control the operation of the lifting rod in the corresponding regulator according to the motor control current output by the second calculation module.

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