KR20220158436A - Control system for smart care bed to prevent bedsores - Google Patents

Abstract

The present invention relates to a control system for a smart care bed for preventing pressure sores. The control system for a smart care bed, according to the present invention, comprises: a body pressure sensor for constantly collecting body pressure sensing information for each part of the body; and an operation control unit for independently controlling each elevating/lowering link module. Therefore, the present invention can prevent serious side effects such as pressure sores or skin diseases.

Description

Control system for smart care bed to prevent bedsores {Control system for smart care bed to prevent bedsores}

The present invention relates to a control system of a smart care bed for preventing pressure sores, and more particularly, to an elevating link having a multi-parallelogram link structure in which elevating and descending is independently controlled in the form of an elevating link module along a bed surface of a bed. By arranging a plurality of modules adjacently in parallel and appropriately controlling the lifting and lowering operation of the lifting link modules according to the patient's nursing situation, a control system of a smart care bed for prevention of bedsores with excellent prevention effects such as bedsores and skin diseases It is about.

In general, medical beds used in hospitals have a structure in which a backrest or footrest can be folded by rotating at a certain angle for patients with mobility difficulties, and a manual type and a driving motor in which a guardian adjusts the angle of the backrest by turning a control handle. Or, it is divided into an electric type that adjusts the angle of the backrest with electric power using a hydraulic cylinder.

The manual medical bed has the advantage of being inexpensive in that it does not require a separate motorized device, but has a problem in that it is difficult to use by the patient himself who has difficulty in moving because it takes a lot of force to adjust the angle of the backrest.

For this reason, in recent years, even though the purchasing cost is somewhat high, a motorized bed in which the patient can adjust the angle of the backrest by himself is preferred.

One example of such a conventional medical electric bed is disclosed in Korean Registered Patent No. 10-0621349 (hereinafter referred to as 'prior literature').

Referring to FIGS. 1 and 2 of the prior art document, the conventional electric medical bed largely includes a bed frame 10, a backrest part 21 located above the bed frame 10 and rotatably coupled to each other, and An operation module 20 including a leg support 22, a drive module 30 composed of a plurality of links rotatably coupled to the operation module 20 and driven by an external force, and the bed frame 10 ) It consists of a power module 40 located at the bottom and providing an external force for the operation of the drive module 30.

The power module 40 is composed of a first actuator 41 and a second actuator 42, and each first actuator 41 applies power so that the backrest 21 tilts, and the second actuator 42 applies power so that the leg support 22 is tilted.

In addition, the backrest part 21 is located on the upper surface of the bed frame 10, one end is rotatably coupled to the fixing part 50 provided in the bed frame 10, and the other end is moved upward by the driving module 30. tilted The thigh part 22a has one end rotatably coupled to the other side of the fixing part 50, and the shin part 22b has one end rotatably coupled to the other end of the thigh part 22a, and the footrest part 22c has one end of the thigh ( It is rotatably coupled to the other end of 22a). In this way, the leg support 22 is configured and the leg support 22 is tilted upward by the drive module 30 coupled to the bed frame 10 .

However, in the conventional medical electric bed configured as described above, the mat part is divided into a backrest part, a waist part, a joint part, a leg support part, etc. and can be driven up and down, so that a critically ill patient who has difficulty moving the body is raised and seated or lifts the legs It is possible to change the posture necessary for back treatment and nursing activities to some extent, but in the case of a patient who cannot move while lying on a bed, certain body parts of the patient are pressed against the bed for a long time, resulting in poor blood circulation and also air on the skin for a long time. There was a serious problem accompanied by complications such as bedsores and skin diseases as they could not be contacted.

Korean Registered Patent No. 10-0621349 (registered on Aug. 31, 2006) Korean Patent Registration No. 10-1709038 (registered on February 15, 2017)

Accordingly, the present invention has been devised to solve the above problems, and the elevating link module of the multiple parallelogram link structure in which the elevating and descending is independently controlled in the form of an elevating link module along the bed surface is adjacent in parallel A control system of a smart care bed for prevention of bedsores using a body pressure sensor having excellent prevention effects such as bedsores and skin diseases by arranging a plurality of them and appropriately controlling the lifting and lowering operation of the lifting link modules according to the patient's nursing situation. intended to provide

According to an embodiment, the control system of the smart care bed for preventing bedsores of the present invention for achieving the above object is a plurality of elevating link modules in which elevating and descending are independently controlled by parallelogram links on the upper surface of the bed support. In the control system of a smart care bed for prevention of bedsores, in which the elevating link modules are arranged adjacently and in parallel, and the operation of each elevating link module is controlled by a servo motor, each elevating link module is provided with each elevating link module a body pressure sensor that constantly collects body pressure sensing information for each part of the body applied to the body; and an operation controller that independently controls each elevating link module by using the body pressure sensing information transmitted from the body pressure sensor, wherein the operation controller controls the body pressure sensing information collected from the body pressure sensors of each elevating and descending link module. When the body pressure sensing information transmitted from the body pressure sensor of a specific elevating link module approaches 32 mmHg, which is the pressure sore critical pressure at which pressure sores can occur, the specific elevating link module close to the pressure sore threshold pressure In the initial first vertical position (h1) in which all the elevating link modules including the specific elevating link module are parallel just before reaching the first vertical position (h1), only the specific elevating link module approaching the pressure sore critical pressure is set to the first vertical position (h1). After descending to the second vertical position (h2), which is relatively lower than ), the operation is stopped for a preset predetermined stay time, and after the predetermined stay time has elapsed, a specific lift that was stopped at the second vertical position (h1) By raising the lowering link module back to the original first vertical position h1, the lifting operation and vertical position of each lifting link module are independently controlled according to the body pressure sensing information, and the body pressure sensor of each lifting link module is controlled. When reading the collected body pressure sensing information fails to independently control the operation and position of a specific elevating link module, the next step is to repeatedly control the elevating operation of each elevating link module for a preset period of time. Time control is performed automatically.

In addition, according to an embodiment, the operation control unit calculates the maximum body pressure in each elevating link module by Equation 1 below,

(수식 1)

(Equation 1)

(Here, Pmi is the maximum pressure of the elevating link module i, Pij is the body pressure measured by the j-th sensor of the i-th elevating link module, and M is the number of body pressure sensors in each elevating link module.)

The error ei is calculated by Equation 2 below,

(수식 2)

(Formula 2)

는 목표 압력값,

는 건반 i의 최대 압력,

는 건반 입력이다.)(here,

is the target pressure value,

is the maximum pressure of key i,

is the keyboard input.)

The total error (e _RMS ) is calculated by Equation 3 below,

(수식 3)

(Formula 3)

(Here, N is the number of lifting and lowering link modules.)

The operation control unit independently controls the lifting and lowering operation and vertical position of each lifting and lowering link module so that the total error value calculated by the above formula converges to 0.

In addition, according to an embodiment, the operation controller uses a proportional-integral (PI) control method or an integral-proportional (IP) control method.

In addition, according to one embodiment, the operation control unit is connected to the servo motor provided in each elevating link module by CAN (Controller Area Network) communication.

In addition, according to one embodiment, in the elevating and descending link module, at least two or more parallelogram links are connected side by side on a horizontal line, and links disposed between each of the parallelogram links share a single link with each other. It has a quadrilateral link structure.

Further, according to an embodiment, among the links shared among the multiple parallelogram links, the link located in the center is a phase offset link in which a vertical position of a coupling axis is located below other links on the left and right.

Also, according to one embodiment, the phase offset link is a driving link coupled to a servo motor.

In addition, according to an embodiment, the duration control is performed by dividing the elevating link modules into odd-numbered and even-numbered elevating link modules, and then performing the elevating operation of the odd-numbered and even-numbered elevating link modules at a preset drop time (T1). and iteratively alternately controlled during the lifting time T2.

Also, according to one embodiment, the sum of the lowering time T1 and the rising lowering time T2 is set to within 30 minutes.

In addition, according to one embodiment, the body pressure sensor may include a user interface unit; a host interface unit; a multi-servo communication unit for connecting the servo motors provided in each of the elevating and descending link modules through wired/wireless communication; and a multi-sensor communication unit that connects the body pressure sensors provided in each elevating/descending link module through wired/wireless communication.

According to an embodiment, the body pressure sensor further includes a body pressure sensing information processing unit for processing body pressure sensing information.

Also, according to an embodiment, the host interface unit is connected to the multi-servo communication unit and the multi-sensor communication unit through controller area network (CAN) communication.

As described above, the present invention arranges a plurality of elevating link modules whose elevating is independently controlled in the form of elevating link modules along the bed surface in parallel and adjacent to each other, and according to the patient's treatment or nursing situation. Excellent medical care that can prevent serious side effects such as pressure ulcers or skin diseases caused by poor blood circulation or lack of contact with air due to the patient's body being pressed on the bed for a long time by appropriately controlling the lifting and lowering movements of the lowering link modules It works.

1 is a perspective view showing a medical electric bed according to the present invention as a whole
Figure 2 is an enlarged perspective view of the main part of the elevating link module according to the present invention according to an embodiment
Figure 3 is an exploded perspective view of Figure 2
Figure 4 is an enlarged perspective view of the main part of the elevating link module according to the present invention according to another embodiment
Figure 5 is an exploded perspective view of Figure 4
Figure 6 is a schematic state diagram for explaining the link operation of the lifting and lowering link module of Figure 4, (a) is a normal motion state in the case of a single parallelogram link, (b) is abnormal due to the occurrence of a turning point in (a) Motion state, (c) is a normal motion state in which the occurrence of a turning point is prevented by applying a double parallelogram link according to the present invention
Figure 7 is a schematic diagram showing the operating mechanism of the elevating link module according to the present invention
8 is a block diagram showing a control system of a smart care bed for preventing bedsores according to the present invention;
9 is a block diagram of an operation control unit of a PI (Proportional-Integral) control scheme according to an embodiment of the present invention.
10 is a block diagram of an operation controller of an integral-proportional (IP) control method according to an embodiment of the present invention.
11 is a graph showing experimental results of operation control of the PI control scheme.
12 is a graph showing experimental results of operation control of the IP control scheme.
13 is a control block diagram of a servo motor driver according to the present invention
14 is a flowchart showing a control method of a smart care bed according to the present invention
15 is a block diagram showing the structure of a fuzzy controller as part of a sensor controller according to the present invention.
16 is a flowchart of duration control according to an embodiment of the present invention.

Terms used in this specification are used only to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "having" to "include" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in this specification, but one or other features, numbers, steps, operations, components, parts, or combinations thereof, or any combination thereof, is not precluded from being excluded in advance.

Unless otherwise defined herein, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this specification, it should not be interpreted in an ideal or excessively formal meaning. Should not be.

Hereinafter, with reference to the accompanying drawings, a detailed look at the configuration and operational relationship of the medical electric bed of the present invention is as follows.

1 is a perspective view showing a medical electric bed of the present invention as a whole, FIG. 2 is an enlarged perspective view of main parts of an elevating link module according to an embodiment of the present invention, and FIG. 3 is an exploded perspective view of FIG. 2 .

Hereinafter, the configuration of a medical powered bed according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3 .

First, the medical electric bed of the present invention is provided with a support frame 200 capable of supporting the body by part at the top of the bed frame 100 made of a normal steel structure. The support frame 200 is divided into a back support portion 210, a waist support portion 220, a knee support portion 230, and a leg support portion 240, and the respective support portions 210, 220, and 230 , The elevation or rotation angle of 240) can be selectively adjusted.

For example, when a patient with reduced mobility is seated, the backrest part 210 can be lifted upwards, while for a patient with a lowered leg, the legrest part 240 can be raised upward or downward, or the rotation angle can be manipulated. this is possible

In addition, a headboard 110 and a footboard 120 are provided on the patient's head and leg sides of the bed frame 100, respectively, and on the side of the bed frame 100 there are vertical and horizontal surfaces to prevent the patient from rolling off the bed. A safety bar 130 that is raised and lowered and fixed is further provided.

On the other hand, as a characteristic component of the present invention, a plurality of elevating link modules whose elevation is independently controlled by parallelogram links on the upper surface of each supporting portion (210, 220, 230, 240) of the supporting frame 200 300 are adjacently arranged in parallel, and a servo motor 390 is coupled to one of the link coupling shafts of each of the elevating link modules 300 to drive the link.

At this time, since the servo motors 390 are separately provided in each of the elevating link modules 300, the elevating and lowering of each elevating link module 300 can be independently controlled by the servo motors 390. It is understandable that there is

Hereinafter, referring to FIGS. 2 and 3, according to an embodiment, each elevating link module 300 has a shape in which two parallelogram link structures are connected side by side on a horizontal line as a whole, and each of the parallelogram links A phase offset link piece 330 is disposed between them, and the two life-time quadrilateral link structures share the phase offset link piece 330 with each other. At this time, in the phase offset link piece 330, the vertical position of the link coupling shaft 331 is lower than the coupling shafts 341 and 351 of the other links on the left and right.

More specifically, each of the elevating link modules 300 includes an upper link frame 310 in which a plurality of coupling ribs 311, 312, and 313 integrally protrude from left to right and have a certain length and are integrally formed with a plurality of coupling ribs 311, 312, and 313 for coupling downward. , It has a structure opposite to the upper link frame 310 as a whole and is composed of a lower link frame 320 disposed below the upper link frame 310 and coupled to a link.

”와 “

”의 형상을 가지며, 이에 따라 상기 하부 링크 프레임(320)의 단면 내부에 서보 모터가 설치 가능하다.The longitudinal cross-sectional shapes in the longitudinal direction and the vertical direction of the upper link frame 310 and the lower link frame 320 are respectively “

"Wow "

It has a shape of “, and accordingly, a servo motor can be installed inside the cross section of the lower link frame 320.

At this time, as shown in FIGS. 2 and 3, the lower link frame 320 has coupling ribs (no reference numerals) formed in the same form as the coupling ribs 311, 312, and 313 of the upper link frame 310. It may be, or even if only coupling holes (no reference numerals) are formed in the lower link frame 320 instead of coupling ribs, the same function as a parallelogram link can be performed. Details of the structure of the lower link frame 320 Description is omitted.

In addition, a plurality of link pieces 330, 340, 350 are coupled between the respective coupling ribs 311, 312, 313 of the upper and lower link frames 310 and 320. First, the middle coupling rib 311 The vertical position of the coupling shaft 331 is coupled to the phase offset link piece 330 located below the other coupling shafts 341 and 351 adjacent to the left and right.

In addition, the first link piece 340 is coupled to the coupling rib 312 formed at the left end of the phase offset link piece 330, and the second link piece 340 is coupled to the right end coupling rib 313 of the phase offset link piece 330. The link piece 350 is hinged. At this time, the coupling shafts 341 and 351 of the first link piece 340 and the second link piece 350 are located above the coupling shaft 331 of the phase offset link piece 330 described above.

In addition, each of the link pieces 330, 340, and 350, that is, the phase offset link pieces 330a and 330b, the first link pieces 340a and 340b, and the second link pieces 350a and 350b are all a pair. It is divided and formed one by one on the left and right at regular intervals to form. Accordingly, when the upper link frame 310 is linked left and right on the lower link frame 320, it is stably supported and linked without shaking in a lateral direction perpendicular to the direction of left and right movement of the link.

At this time, as described above, among the coupling ribs 311, 312, and 313 of the upper link frame 310, the coupling rib 311 to which the phase offset link piece 330 in the middle is coupled is the other coupling ribs 312 and 313 ) is formed with a longer length downward than Accordingly, the vertical position of the coupling shaft 331 located in the middle is lower than the other coupling shafts 341 and 351 on the left and right.

In addition, as described above, the servo motor 390 is installed inside the lower link frame 320, and the rotation shaft of the servo motor 390 is coupled to the phase offset link piece 330 to function as a driving shaft. Therefore, as the phase offset link piece 330 is driven left and right by the electric force of the servo motor 390, the first link piece 340 and the second link piece 350 linked therewith also move left and right simultaneously. get to exercise

In addition, a bed piece 380 for supporting the weight of the body is further provided on the upper surface of each upper link frame 310 . The bed piece 380 may be, for example, a cushion material in which a waterproof coating is finished on the outside of a sponge, or a hard wooden material without a cushion feeling.

Meanwhile, FIG. 4 is an enlarged perspective view of main parts of an elevating link module according to another embodiment of the present invention, and FIG. 5 is an exploded perspective view of FIG. 4 . 4 and 5 are other embodiments of FIGS. 2 and 3 described above, and illustrate that the elevating link module of the present invention is implemented in the form of a quadruple parallelogram link.

More specifically, the quadruple parallelogram link is a structure in which three links are shared between each parallelogram link, and the third link piece 360 and the fourth link piece 370 are added to the structure of the double parallelogram link described above. ) has an added configuration. Accordingly, coupling ribs 314 and 315 and coupling shafts 361 and 371 for link coupling the third and fourth link pieces 360 and 370 are further formed in the upper link frame 310, respectively.

Therefore, as described in one embodiment, the phase offset link piece 330 is driven according to the driving of the servo motor 390 coupled to the satellite offset link piece 330, and accordingly the phase offset link piece 330 The linked first to fourth link pieces 340, 350, 360, and 370 are also moved simultaneously.

The quadruple parallelogram link structure is more stable in terms of load bearing and operation reliability as it is supported by more link pieces than the double parallelogram link structure.

Figure 6 is a schematic state diagram for explaining the link operation of the lifting and lowering link module of Figure 4, (a) is a normal motion state in the case of a single parallelogram link, (b) is abnormal due to the occurrence of a turning point in (a) The motion state (c) is a normal motion state in which the occurrence of a turning point is prevented by applying a double parallelogram link according to the present invention.

Hereinafter, looking at the link operation of the elevating link module according to the present invention with reference to FIG. 6, FIG. 6a attached first illustrates the case of a single parallelogram link to which the present invention is not applied. In this case, in the normal motion state, most of the links perform normal motion while maintaining the structure of the parallelogram link as a whole.

However, as shown in FIG. 6B, in the single parallelogram link structure of FIG. 6A, a change point problem in which the driven link does not properly follow the movement of the driving link in one direction may occasionally occur.

Here, the turning point is a phenomenon in which all links are placed on a straight line as shown in FIG. 6B. When such a turning point occurs, the motion of the output link becomes unpredictable. In this case, unlike the normal motion in FIG. Abnormal movements that generate shock and vibration occur.

Accordingly, it is proposed to apply multiple parallelogram links in the form of connecting and installing at least two parallelogram links to the link in the elevating link module according to the present invention in order to fundamentally prevent the occurrence of such a turning point.

As an example of such a multiple parallelogram link, a double parallelogram link may be applied as described above in FIGS. 2 and 3, and an example thereof is schematically shown in FIG. 6C.

In the double parallelogram link shown in FIG. 6C, the coupling axis 331 of the shared link located at the center, that is, the phase offset link piece 330, is lower on the horizontal line than the coupling axes 341 and 351 of the other links on the left and right. It has the form of a located phase offset link.

Therefore, during the circular motion of the double parallelogram link, the occurrence of a turning point is prevented by the phase offset link piece 330, and accordingly, the occurrence of abnormal motion is prevented.

Meanwhile, in a state in which the phase offset link piece 330 is erected vertically, the upper link frame 310 is located at the highest point, and at this time, the elevating link module 300 is in an elevated state.

On the other hand, in a state in which the phase offset link piece 330 is rotated left and right, the upper link frame 310 is located at the lowest point, and accordingly, the elevating link module 300 is in a lowered state.

Therefore, it is possible to independently control the elevation and descent of each elevating link module 300 as described above, and accordingly, the upper link frame 310 and the bed piece 380 of each elevating link module 300 ) It is possible to change the shape so that the upper surface of the upper surface forms a plane side by side on a horizontal surface or forms a concave-convex surface.

Accordingly, in the case of a patient who has to lie in bed for a long time, the body condition needs to be changed periodically or by situation. It is possible to prevent serious side effects such as pressure ulcers, which can be caused by blood circulation being interrupted by being continuously pressed or air not being in contact with the skin.

Meanwhile, in FIG. 6C, only the case of a double parallelogram link is exemplified, but multiple parallelogram links are also possible. For example, as in the other embodiments of the present invention described in FIGS. 4 and 5 described above, it is possible to apply a quadruple parallelogram link, and in this case, it is possible to support a load more firmly than a double parallelogram link, as well as suppress the occurrence of a turning point more reliably. Therefore, it is possible to obtain the effect of improving the reliability of operation.

Figure 7 is a schematic diagram showing the operating mechanism of the elevating link module according to the present invention.

Hereinafter, referring to FIG. 7, the operating mechanism of the elevating link module 300 according to the present invention will be described. The height value (h) of the upper link frame 310 is determined according to the length (r) of 340 and 350.

In addition, by substituting the height to be operated into Equations 1 and 2 below, the necessary rotation angle of the servo motor 390 can be obtained.

(수식 1)

(Equation 1)

(수식 2)

(Equation 2)

는 승하강 링크 모듈(300)의 회전각도이고,

은 승하강 링크 모듈(300)의 회전반경, 그리고

는 승하강 링크 모듈(300)의 높이(수직 위치)로서, h1은 승하강 링크 모듈(300)이 평행한 초기의 수직 위치, h2는 승하강 링크 모듈(300)이 △h만큼 하강한 상태의 수직 위치이다.here

Is the rotation angle of the elevating link module 300,

is the rotation radius of the elevating link module 300, and

is the height (vertical position) of the elevating link module 300, h1 is the initial vertical position in which the elevating link module 300 is parallel, h2 is the state in which the elevating link module 300 is lowered by Δh is in a vertical position.

In the control system of a smart care bed for preventing bedsores of the present invention, a plurality of elevating link modules 300 independently controlled by parallelogram links are disposed adjacent to each other in parallel on the upper surface of the bed support. The operation of the lifting and lowering link module is controlled by the servo motor 390 .

To this end, first, through the body pressure sensor 1510 provided in each of the elevating link modules 300, body pressure sensing information for each part of the human body applied to each elevating link module 300 is constantly collected and an operation control unit send.

Next, the operation controller 1200 reads the body pressure sensing information collected from the body pressure sensors 1510 of each elevating link module 300 and transmits the information from the body pressure sensor 1510 of the specific elevating link module 300. When the received body pressure sensing information approaches 32 mmHg, which is the pressure sore critical pressure at which pressure sores can occur, the specific elevating link module 300 close to the pressure sores critical pressure reaches the specific elevating link module 300 In the initial first vertical position h1 in which all elevating link modules 300 including 300 are parallel, only the specific elevating link module 300 approaching the pressure sore critical pressure is in the first vertical position h1 After descending to a relatively lower second vertical position h2, the operation is stopped for a predetermined stay time.

Next, each elevating link module 300 stopped at the second vertical position h1 is raised to the original first vertical position h1 after the predetermined stay time has elapsed. The ascending and descending motion and vertical position of the module 300 are independently controlled according to body pressure sensing information.

For example, the period of the predetermined staying time may be set to 5 seconds or more in consideration of the time when the elevating link module 300 goes down and the time when the body pressure is stabilized after going down.

8 is a block diagram showing a control system of a smart care bed for preventing bedsores according to the present invention.

The control system 1000 of the present invention uses a user interface unit 1100, an operation control unit 1200, a host interface unit 1300, and servo motors 1410 provided in each of the lifting and lowering link modules 300 through wired/wireless communication. A multi-sensor communication unit 1500 that connects the body pressure sensor 1510 and the sensor controller 1520 provided in each elevating link module 300 through wired/wireless communication. can

In addition, the control system 1000 may further include a sensor signal processing unit 1600 for processing a body pressure sensor signal of the body pressure sensor 1510 .

According to an embodiment, the host interface unit 1100, the multi-servo communication unit 1400, and the multi-sensor communication unit 1500 may be connected by CAN (Controller Area Network) communication.

More specifically, the control system 1000 of the present invention includes 16 servo motor drivers 1420 for driving 16 elevating and lowering link modules 300 and a user interface connected to them through CAN (Controller Area Network) communication. 1100, an operation control unit 1200, and a host interface unit 1300.

At this time, the user interface unit 1100 may be a teach pendant indicating an operation mode of the bed.

In addition, the CAN (Controller Area Network) communication is a standard communication standard designed to allow microcontrollers or devices to communicate with each other in a vehicle without a host computer.

According to one embodiment, 16 three-phase BLDC motors may be used as the servo motor 1410 of the present invention, and the servo motor driver 1420 for driving the servo motors 1410 up and down each receives a hall sensor signal. A driver of the used square wave driving method may be used.

For example, the servo motor driver 1420 can be mounted on each elevating link module 300, and the host interface unit 1300 communicating with the servo motor driver 1420 has two CAN communication ports and one RS485 communication port may be included.

In addition, the servo motor driver 1420 is capable of position control or speed control, and the position control and speed control modes can be set in real time using a CAN message. In addition, ID recognition of the 16 servo motor drivers 1420 may be sequentially set using the I/O of each driver 1420 .

Here, the BLDC servo motor 1410 is capable of sufficient position control with only the signal information of the hall sensor, so an algorithm for calculating position information with a three-phase hall sensor is installed in the control system of the present invention, and supports CAN communication and RS485 communication The hardware of the servo motor driver 1420 can be configured to do this.

The operation control unit 1200 transmits position and speed control commands to the servo motor driver 1420 through CAN communication of the host interface unit 1300, and the servo motor driver 1420 transmits commands to each servo motor 1410. Ascending and descending motions and vertical positions are performed.

According to an embodiment, the body pressure sensor 1510 may be a thin film body pressure sensor of the FSR type. The body pressure sensors 1510 are mounted on each elevating link module, and M body pressure sensors 1510 are connected to the sensor controller 1520. Then, the N sensor controllers 1520 transmit NM pieces of body pressure sensing information to the operation controller 1200 through CAN communication, and the larger the number of NMs (the greater the number of NMs), the higher the resolution of the body pressure sensing map.

However, it is preferable that the number of N and M is limited to an appropriate number for physical and practical reasons.

Accordingly, when a control command is transmitted from the operation control unit 1200 to the servo motor drivers 1420 installed in each of the 16 elevating and descending link modules 300 through CAN communication, the servo motor drivers 1420 transmit each elevating and descending link. By controlling the module 300, it is driven up and down independently to prevent bedsores.

In the present invention, as an operation control unit for independently controlling the elevation and vertical position of the servo motor, a PI control method and an IP control method operation control unit may be used.

The PI control method generates an output proportional to the error between the command value and the measured value and the integral of the error, whereas the IP control method generates an output proportional to the integral of the error between the command value and the measured value and the measured value.

In the case of an IP controller, since there is no zero point in the transfer function, it is easy to set the control gain so that the overshoot and stabilization time have the desired characteristics. can do. That is, since the bandwidth can be increased, better response characteristics to disturbances can be obtained.

9 is a block diagram of an operation controller of a proportional-integral (PI) control scheme according to an embodiment of the present invention.

The vertical position movement amount (Δh, see FIG. 7) of the elevating link module can be modeled as being adjusted for the difference between the current body pressure and the critical body pressure (32 mmHg).

Assuming that the operation controller of the PI control method is a primary system and expressed as a closed loop transfer function, Equation 3 is shown below.

(수식 3)

(Formula 3)

(수식 4)

(Formula 4)

Here, Pmi is the maximum pressure of the i-th lifting link module, kp is a proportional term, ki is an integral term,

에 영점이 존재하고 있으며, 이 영점의 영향으로 인해 오버슈트(overshoot)의 크기가 증가한다. 그러므로 PI 제어 시스템에서 이러한 영점에 의한 오버슈트 응답의 문제점은 IP 제어 방식의 동작 제어부를 사용하면 해결할 수 있다.In the case of the operation controller of the PI control method in Equation 4,

There is a zero point in , and the size of overshoot increases due to the influence of this zero point. Therefore, in the PI control system, the problem of overshoot response by the zero point can be solved by using the IP control type operation control unit.

10 is a block diagram of an operation controller of an integral-proportional (IP) control method according to another embodiment of the present invention.

Unlike the operation controller of the PI control method that proportionally controls the body pressure error (e), the operation controller of the IP control method performs proportional control on output body pressure sensing information.

When the block diagram of FIG. 10 is expressed as a transfer function, it is expressed as Equation 5 below.

(수식 5)

(Formula 5)

In the operation control unit of the IP control method of Equation 5, the zero point of the PI control method is removed so that overshoot can be reduced.

Experimental example of control performance of PI control method and IP control method

In this experimental example, the operation control unit 1200 of the PI control method and the IP control method was applied to adjust the error (e) between the body pressure applied to each elevating link module 300 and the pressure sore critical pressure, respectively. . The height (h, vertical position) of the elevating link module 300 is controlled by the operation control unit 1200 using a PI or IP control method.

And, the maximum body pressure in each elevating link module 300 is calculated by Equation 6 below.

(수식 6)

(Formula 6)

Here, Pmi is the maximum pressure of the i-th elevating link module, Pij is the body pressure measured by the j-th sensor of the i-th elevating link module, and M is the number of body pressure sensors of each elevating and descending link module.

At this time, when the maximum body pressure value exceeds 32 mmHg, the pressure sore critical pressure at which pressure sores can occur is exceeded, and when a certain period of time continues, actual pressure sores occur.

Also, the error ei can be calculated by Equation 7 below.

(수식 7)

(Formula 7)

는 목표 압력값,

는 건반 i의 최대 압력,

는 건반 입력이고 이때, 전체 에러는 다음과 같이 계산한다.here,

is the target pressure value,

is the maximum pressure of key i,

is the keyboard input. At this time, the total error is calculated as follows.

Also, the total error can be calculated by Equation 8 below.

(수식 8)

(Equation 8)

N is the number of elevating and descending link modules.

의 특성을 비교 검토하였다.Adjust the height (h, vertical position) of the elevating link module according to the above formula, and when the body pressure value fluctuates with respect to the changed height

The characteristics of were compared and reviewed.

Through the above-described process, in this experiment, the operation control unit of the PI or IP control method is applied to adjust the height of the elevating link module, and errors applied to each elevating link module are removed so that the total error converges to zero. was set as the experimental goal.

As the elevating link module is lowered, the body pressure applied to the corresponding elevating link module also decreases. However, if the elevating link module rapidly descends, the patient may be burdened. It is desirable to control the height adjustment in the direction of reducing the difference.

In this experiment, it was compared and reviewed that the lifting and lowering link module descends step by step and the total error becomes zero with minimal movement.

For example, the timer cycle of the operation controller is set to 5 seconds or more in consideration of the time when the elevating link module goes down and the time when the body pressure is stabilized after going down.

The operation control parameter values of the PI control method used in the experiment are shown in Table 1 below.

(mm Hg) 0.5 0 32 0.5 One 32

In the motion control experiment of the PI control method, body pressure control was tested for the supine position of an adult male of 175 cm and 88 kg in a smart care bed equipped with a body pressure sensor. The experiment was divided into a case with only a proportional term (P control) and a case with a proportional-integral term (PI control).

11 is a graph showing experimental results of operation control of the PI control method.

As shown in FIG. 11, it was confirmed that the total error converged to 0 more quickly because the PI control in the case of integral (I) control reduced the residual deviation.

Table 2 below is an experimental result table summarizing the numerical data of the PI control method. (In the following, the keyboard refers to the elevating link module.)

key number Error before control (mmHg) Maximum body pressure before control (mmHg) Error after control (mmHg) Maximum body pressure after control
(mm Hg) keyboard height
(mm) One 0 0 0 0 0 2 0 0 0 0 0 3 0 13 0 14 0 4 0 0 0 5 0 5 0 17 0 15 0 6 -5 37 0 20 -4 7 0 0 0 0 0 8 0 0 0 4 0 9 0 28 0 16 0 10 -5 37 0 21 -3 11 0 0 0 0 0 12 0 20 0 16 0 13 0 23 0 14 0 14 -7 39 0 21 -18 15 -5 37 0 20 -5 16 0 0 0 0 0 17 -2 34 0 17 -14

Meanwhile, the operation control parameter values of the IP control method used in the experiment are shown in Table 3 below.

(mm Hg) 0.3 0.3 32 0.3 1.2 32

Meanwhile, FIG. 12 is a graph showing experimental results of an operation controller of an IP control scheme.

Comparing the experimental results of the PI and IP control methods, it was confirmed that the time to converge to 0 was faster because the PI control method proportionally controlled the error with the pressure sore threshold pressure.

On the other hand, it was observed that the IP control stably converges to 0, but takes longer than the PI control method, and the patient may not feel comfortable because the lifting link module is in a vibrating state during this time.

Therefore, as described above, after mounting a body pressure sensor for each elevating link module of a smart care bed composed of a plurality of elevating link modules, each elevating link module is controlled by PI control and IP control methods according to body pressure sensing information. The control performance test of the motion control unit was performed separately.

To this end, the PI control method and the IP control method are developed by measuring the body pressure of each part of the body through each body pressure sensor, controlling it as feedback, and controlling the body pressure detected by each elevating link module to within the pressure sore critical pressure (32mmHg). In the smart care bed according to the present invention, the PI control method is more advantageous than the IP control method in pressure control speed or the movement amount of the elevating link module in order to remove pressure sores by comparing and examining the number of operations of the elevating link module until each converges to 0. was confirmed through experiments.

13 is a control block diagram of a servo motor driver according to the present invention.

Accordingly, when a control command is transmitted from the operation control unit 1200 to the servo motor drivers 1420 installed in each of the 16 elevating and descending link modules 300 through CAN communication, the servo motor drivers 1420 transmit each elevating and descending link. By controlling the module 300, it is driven up and down independently to prevent bedsores.

14 is a flowchart showing a control method of a smart care bed according to the present invention.

The control method of the present invention can be controlled by dividing into a first step body pressure control and a second step duration control.

The first-step body pressure control may be performed by, for example, a fuzzy logic system (FLS) programmed in the motion control unit.

The fuzzy logic system (FLS) may define a non-linear mapping of an input data set to scalar output data, and the fuzzy logic system may be composed of four main parts: fuzzification, rule checking, inference, and defuzzification. .

The fuzzy logic process of the fuzzy logic system is as follows.

First, a clear input data set is collected and transformed into a fuzzy set using fuzzy language variables, fuzzy language terms, and membership functions. (This step is known as fuzzification)

Inferences are then made based on a set of rules.

Finally, the fuzzy output value is determined using the membership function in the defuzzification step.

At this time, a fuzzy controller is used as a sensor controller 1520 to adjust the error between the pressure applied to each elevating link module 300 and the pressure sore critical pressure, and the structure of the fuzzy controller is shown in FIG. 15 .

15 is a block diagram showing the structure of a fuzzy controller as part of a sensor controller according to the present invention.

Referring to FIG. 15 , a body pressure sensor 1510 is mounted on each elevating link module 300, and the height of the elevating link module 300 can be controlled by the fuzzy controller.

Here, Pcu is the pressure sore critical pressure, Pmi is the maximum pressure of the elevating link module i, hi is the height of the elevating link module i, ei is the difference between Pcu and Pmi (Pcu-Pmi), and ui (=hi) is the elevating and descending This is the movement amount of the link module.

Also, the error ei can be calculated by Equation 9 below.

(수식 9)

(Formula 9)

Also, the total error can be calculated by Equation 10 below.

(수식 10)

(Equation 10)

N is the number of elevating and descending link modules.

는 하기 수식 11에 의해 구해질 수 있다. In addition, the maximum pressure of the i-th lifting and lowering module

Can be obtained by Equation 11 below.

(수식 11)

(Equation 11)

M is the number of body pressure sensors of each elevating link module.

Here, M is the number of body pressure sensors of each elevating link module, and Pij is the body pressure measured by the j th sensor of the i th elevating link module.

는 하기 수식 12에 의해 구해질 수 있다.In addition, in each lifting link module, the pressure ratio

Can be obtained by Equation 12 below.

, i=1,2,....N, j=1,2...M (수식 12)

, i=1,2,....N, j=1,2...M (Equation 12)

Here, Pij is the body pressure measured by the j-th sensor of the i-th elevating and descending link module.

Through the above process, it is possible to perform fuzzy body pressure control of the elevating link module for preventing bedsores by the fuzzy controller.

On the other hand, when the body pressure control by the body pressure sensor in the first step fails (eg, when the patient is severely overweight), the duration control is performed as a second step.

16 is a flowchart of duration control according to an embodiment of the present invention.

The elevating link module (keyboard, 300) of the smart care bed repeatedly performs a pressure sore prevention operation for a preset time, and the odd-numbered elevating link module and the even-numbered elevating link module alternately lift and lower.

That is, after a predetermined period of time, the odd-numbered or even-numbered elevating link module descends to zero body pressure, or when the elevating link module rises again, the body pressure duration is longer than the normal position change time (2 hours). In principle, it was made to be much shorter so that bedsores did not occur. In addition, the elevated elevating link module automatically descends again after a critical duration, and the body pressure of the corresponding contact portion pressed by the human body becomes zero.

In principle, it is known that the position change time for body pressure control is within two hours, but the shorter the position change time is, the better, and during T1 (= 7 min), the even or odd number of lifting link modules descend During T2 (= 3min), it is defined that the elevating link module rises again to maintain a flat bed elevating link module, and the elevating link module repeats the lifting and lowering every T1 + T2 (= 10min). was written.

As a result of previous studies on the intensity and duration of applied pressure and the occurrence of pressure ulcers, histological changes occurred in the body when pressure was applied for 30 minutes at a pressure of 100 mmHg or more and for more than 1 hour at a pressure of 45 to 80 mmHg. It is known to do

At this time, since the repeatedly applied pressure causes mild histological changes at 45 to 60 mmHg and moderate or moderate at 80 mmHg, the clinically recommended postural change time of 2 hours is not sufficient for the prevention of pressure ulcers. For prevention, it is recommended to reduce the body-bed surface pressure to 45 mmHg or less by shortening the postural change cycle or using a special mattress.

Particularly noteworthy is that the conventional automatically pressure-controlled cylindrical air mattress has a sufficient pressure reduction to prevent pressure sores, but the mattress should be used for the hip area. There is currently no clear standard for the lower limit of the pressure value that induces the occurrence of pressure sores, but it is known that the risk of pressure sores increases when a pressure of about 60 mmHg or more occurs.

Therefore, since histological changes occur in 30 minutes at 100 mmHg based on the results of the preceding studies, in the present invention, body pressure is changed every 10 minutes much earlier than this, so that histological changes do not occur.

Accordingly, T1 and T2 are configurable in the user interface 1100 so that the pressure ulcer prevention cycle can be changed, and they need to be optimally set for patient comfort and effective prevention of pressure ulcers.

That is, the second-step duration control is a control method for forcibly performing the elevating operation of the elevating link module (keyboard 300) and the duration of the elevating operation for a preset time.

A summary of the duration control process is as follows.

For example, odd-numbered or even-numbered elevating link modules (keyboards 300) alternately forcibly elevate and descend for a set time, and when the odd-numbered or even-numbered elevating link modules 300 descend, the lowering The body pressure applied to one elevating link module 300 becomes zero.

Then, after a certain period of time has elapsed, the process of raising the lowered elevating link module 300 upward again is repeated.

At this time, the alternate lifting time (T1 + T2) of the odd-numbered and even-numbered lifting link modules may proceed within 10 minutes.

Therefore, when the duration control is performed as described above, the occurrence of pressure sores can be fundamentally prevented by distributing the body pressure of the human body.

That is, in one step, a body pressure sensor is attached to each elevating link module, the body pressure is directly sensed by the body pressure sensor, and the body pressure sensing information is transmitted to the operation control unit to appropriately perform elevating and descending of the elevating link module. Fuzzy body pressure control ( By controlling it through artificial intelligence control), it is possible to distribute the body pressure of the human body and prevent pressure sores through this.

In addition, as an exceptional case, when the first-step fuzzy body pressure control fails due to overweight, etc., the operation of the plurality of elevating link modules is controlled within the body pressure threshold duration through the second-step duration control. It is possible to completely prevent pressure sores by moving the modules up and down alternately.

Therefore, the present invention is independent of the body pressure applied differently to each body part without compromising the comfort of a user with reduced mobility, unlike the simple alternate lifting method over time commonly used in conventional bedsore mattresses or pneumatic cylinder-controlled medical beds. It was possible to confirm the effect of dispersion control.

In addition, the present invention is not limited only by the above-described embodiment, and since the same effect can be created even when the detailed configuration or number and arrangement structure of the device is changed, those of ordinary skill in the art can use the present invention It is stated that addition, deletion, and modification of various configurations are possible within the scope of the technical idea of

100: bed frame 110: headboard
120: footboard 130: safety bar
200: support frame 300: elevating link module
310: upper link frame 320: lower link frame
330: phase offset link piece 340: first link piece
350: 2nd link 360: 3rd link
370: 4th link section 380: bed section
390: servo motor 1000: control system
1100: user interface unit 1200: operation control unit
1300: host interface unit 1400: multi-servo communication unit
1410: servo motor 1420: servo motor driver
1500: multi-sensor communication unit 1510: body pressure sensor
1520: sensor controller 1600: sensor signal processing unit

Claims (12)

A plurality of elevating link modules whose elevating and descending is independently controlled by parallelogram links are disposed adjacently and in parallel on the upper surface of the bed support unit, and each elevating link module is controlled by a servo motor to prevent pressure sores. In the control system of the smart care bed,
a body pressure sensor provided in each of the elevating link modules and constantly collecting body pressure sensing information for each part of the human body applied to each elevating link module; and
An operation control unit that independently controls each elevating and descending link module using body pressure sensing information transmitted from the body pressure sensor,
The operation control unit reads the body pressure sensing information collected from the body pressure sensors of each elevating and descending link module, and determines that the body pressure sensing information transmitted from the body pressure sensor of a specific elevating and descending link module is 32 mmHg, which is a pressure sore critical pressure at which pressure sores can occur. If approaching
the pressure sore critical pressure at an initial first vertical position h1 in which all elevating link modules including a specific elevating link module are parallel before a specific elevating link module approaching the pressure sore critical pressure reaches the pressure sore threshold; After lowering only a specific elevating link module close to the first vertical position (h1) to a second vertical position (h2) relatively lower than the first vertical position (h1), stop the operation for a predetermined stay time,
After the predetermined stay time has elapsed, the specific elevating link module stopped at the second vertical position (h1) is raised to the original first vertical position (h1), thereby raising and lowering each elevating link module and The vertical position is independently controlled according to body pressure sensing information,
If it fails to independently control the operation and position of a specific elevating link module by reading the body pressure sensing information collected from the body pressure sensor of each elevating link module,
to the next step,
Duration control for repeatedly controlling the lifting operation of each lifting link module for a preset time is automatically performed,
A control system for a smart care bed to prevent bedsores. According to claim 1,
The operation control unit,
The maximum body pressure in each elevating link module is calculated by Equation 1 below,

(Equation 1)
(Here, Pmi is the maximum pressure of the elevating link module i, Pij is the body pressure measured by the j-th sensor of the i-th elevating link module, and M is the number of body pressure sensors of each elevating link module.)
The error ei is calculated by Equation 2 below,

(Formula 2)
(here,

is the target pressure value,

is the maximum pressure of key i,

is the keyboard input.)
The total error (e _RMS ) is calculated by Equation 3 below,

(Formula 3)
(Here, N is the number of lifting and lowering link modules.)
The operation control unit independently controls the lifting operation and vertical position of each lifting link module so that the total error value calculated by the above formula converges to 0.
A control system for a smart care bed to prevent bedsores. According to claim 1,
The operation control unit,
PI (Proportional-Integral) control method or IP (Integral-Proportional) control method operation control unit is used,
A control system for a smart care bed to prevent bedsores. According to claim 1,
The operation controller is connected to the servo motor provided in each elevating link module by CAN (Controller Area Network) communication,
A control system for a smart care bed to prevent bedsores. According to claim 1,
The elevating link module,
At least two or more parallelogram links are connected side by side on a horizontal line, and the links disposed between each of the parallelogram links have a multiple parallelogram link structure in which a single link is shared with each other,
A control system for a smart care bed to prevent bedsores. According to claim 5,
Among the links shared between the multiple parallelogram links, the link located in the center is a phase offset link in which the vertical position of the coupling axis is lower than the other links on the left and right,
A control system for a smart care bed to prevent bedsores. According to claim 6,
The phase offset link is a driving link to which a servo motor is coupled.
A control system for a smart care bed to prevent bedsores. According to claim 1,
The duration control,
After dividing the elevating link modules into odd-numbered and even-numbered elevating link modules, the elevating operation of the odd-numbered and even-numbered elevating link modules is repeatedly and alternately controlled during a preset lowering time T1 and a lifting time T2. ,
A control system for a smart care bed to prevent bedsores. According to claim 8,
The sum of the lowering time (T1) and the lowering time (T2) is within 30 minutes,
A control system for a smart care bed to prevent bedsores. According to claim 1,
In the body pressure sensor,
user interface unit; a host interface unit; a multi-servo communication unit for connecting the servo motors provided in each of the elevating and descending link modules through wired/wireless communication; and a multi-sensor communication unit for connecting body pressure sensors provided in each elevating link module through wired/wireless communication.
A control system for a smart care bed to prevent bedsores. According to claim 1,
In the body pressure sensor,
A body pressure sensing information processing unit for processing body pressure sensing information is further provided.
A control system for a smart care bed to prevent bedsores. According to claim 10,
The host interface unit,
Connected by multiple servo communication units and multiple sensor communication units and CAN (Controller Area Network) communication,
A control system for a smart care bed to prevent bedsores.

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