CN111413014B - Optical fiber pressure detection system - Google Patents

Optical fiber pressure detection system Download PDF

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Publication number
CN111413014B
CN111413014B CN202010216977.2A CN202010216977A CN111413014B CN 111413014 B CN111413014 B CN 111413014B CN 202010216977 A CN202010216977 A CN 202010216977A CN 111413014 B CN111413014 B CN 111413014B
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fiber
patient
signal
optical fiber
bed
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CN111413014A (en
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王德利
朱晓红
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Peking University Shenzhen Hospital
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Peking University Shenzhen Hospital
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
    • G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
    • A61B5/1113—Local tracking of patients, e.g. in a hospital or private home
    • A61B5/1115—Monitoring leaving of a patient support, e.g. a bed or a wheelchair

Abstract

The invention relates to an optical fiber pressure detection system, at least comprising: the main supporting part is arranged on the first detection supporting surface and a first optical fiber sensor group is paved in the main supporting part, and the detection mechanism further comprises: at least one vice supporting part, it is arranged in the second and is surveyed on the holding surface and its vice supporting part inside has laid second optical fiber sensor group, and first optical fiber sensor group and second optical fiber sensor group include at least one fiber grating sensor respectively, main supporting part and at least one vice supporting part is followed pressure detection mechanism's first direction is arranged side by side, and first optical fiber sensor group is laid according to at least one fiber grating sensor along the mode that first direction is density wave form and arranges on the main supporting part, the fiber grating sensor is used for detecting the optical signal who is lain the appearance change and causes by the user on main supporting part surface and changes.

Description

Optical fiber pressure detection system
Technical Field
The invention relates to the technical field of nursing equipment, in particular to an optical fiber pressure detection system.
Background
At present, invasive contact detection methods and non-invasive contact detection methods are mainly adopted for the bed-leaving judgment of patients or old people. The invasive contact detection method is mainly realized by connecting equipment to a user or enabling the user to wear wearable equipment. Most of the monitoring to two indexes of user's breathing, heart rate mainly uses gel electrode slice or wearable equipment to monitor. However, this method requires the electrode sheet to be attached to the body of the human body or the user to wear the wearable device, a large number of circuits and different devices are connected to the human body, the user experience is very bad, and the movement is very inconvenient. Such as: when a user gets up, all connecting wires need to be pulled out. When the user returns, the user needs to connect all the wires, and the use is extremely inconvenient. When a user uses the wearable device, the user needs to wear it on the body at all times due to the shape and weight of the device. Users are often reluctant to wear these devices when the weather is hot. The non-invasive contact detection method mainly detects the state of a user on a bed by installing some detection sensors around the bed. However, this method is not portable. When the user changes to another bed, the sensors need to be reinstalled around the new bed. The prior art typically uses piezoelectric sensors to detect body activity, respiration rate and heart rate. The piezoelectric transducer is composed of piezoelectric transducer ceramics or single crystal materials, and the materials are hard and influence the use feeling of people when being used for mattresses or bedding. And the sensitivity of the material is reduced along with the time, and the sensitivity is reduced more quickly when the temperature is increased, so that the measurement data has inevitable deviation. Temperature drift associated with mattress heat conduction and patient temperature remains a difficult problem for bed exit detection.
A patent with publication number CN201810128650.2 in the prior art discloses a bed exit monitoring device, comprising: the bed leaving induction device and the master control device are arranged in a split manner; the bed leaving sensing device is connected with the master control device in a wireless communication mode; the bed leaving sensing device is used for monitoring whether a user leaves the bed abnormally or not and sending an abnormal bed leaving signal to the main control device when detecting that the user leaves the bed abnormally; and the master control device is used for triggering the alarm information to be sent to the target mobile communication user through the mobile communication network after receiving the abnormal bed leaving signal. Particularly, the 'jump change' of the punctiform pressure caused by the elbow to the mattress can often cause the local pressure to sharply increase and decrease.
The bed leaving monitoring device provided by the patent tries to detect the abnormal bed leaving of a user by arranging a plurality of pressure sensors on the bed, but in practical application, on one hand, the device cannot monitor the state of the user leaving the bed, and only can inform medical care personnel after the user leaves the bed, so that the expected nursing effect cannot be achieved; on the other hand, the abnormal out-of-bed state obtained by the device is obtained based on the pressure change caused by the relevant action of the user on the bed body, but actually, the pressure change of the user is carried out by the user alone or is assisted by family members/medical staff, the abnormal out-of-bed state which needs alarm is obtained by the device, and the false alarm frequency is too high.
Aiming at the self-leaving-bed behaviors of high-risk people who easily fall down, the prior art also provides a large number of technical schemes for detecting abnormal leaving-bed of a user based on a pressure sensor arranged on a bed body, but most of the technical schemes can only alarm when a detection object leaves the bed, so that the timeliness is poor, the technical schemes can not distinguish whether the leaving-bed behaviors occur under the condition of no monitoring or monitoring, and the false alarm rate is often too high.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides the optical fiber pressure detection system simultaneously provided with the mattress and the ground mat based on the difference between the pressure information acquired under two different conditions of monitoring and non-monitoring, so that the abnormal bed leaving trend of a user can be monitored, medical staff is informed to assist in time before the user wants to leave the bed, whether the bed leaving behavior occurs under the condition of non-monitoring or monitoring can be accurately judged, and the optical fiber pressure detection system has better timeliness and alarm accuracy.
The invention provides an optical fiber pressure detection system which comprises a main bearing part, a first optical fiber sensor group and a second optical fiber sensor group, wherein the main bearing part is arranged on a first detection supporting surface; the detection system further comprises: at least one auxiliary bearing part which is arranged on the second detection supporting surface and a second optical fiber sensor group is laid in the auxiliary bearing part; the first optical fiber sensor group and the second optical fiber sensor group respectively comprise a plurality of optical fiber grating sensors which are unevenly arranged along an optical fiber, wherein the main bearing part and at least one auxiliary bearing part are arranged in parallel along a first direction of the pressure detection mechanism, the first optical fiber sensor group is laid on the main bearing part in a density waveform arrangement mode along the first direction according to at least one optical fiber grating sensor, and the optical fiber grating sensors are used for detecting optical signal changes caused by a detection object positioned on the main bearing part. The fiber optic pressure sensing system of the present invention is used to analyze such optical signal "variations". According to the change, the optical fiber pressure detection system can judge that the lying posture of the user is changed. The detection and analysis of the light signal change and thus the pressure change is obviously different from the existing technology for judging the existence of the light signal. The method has the advantages of detection accuracy and timeliness, and provides more obvious characteristic data when the method works in combination with the intelligent wearable device, so that the artificial intelligence training is facilitated.
The "main bearing part" refers to a main part capable of providing a supporting function for the detection object, and the main bearing part is arranged on the first detection supporting surface. The "sub bearing portion" refers to a secondary portion capable of providing a supporting function for the detection object, and the sub bearing portion is provided on the second detection support surface. For the convenience of understanding, the primary bearing part is taken as an example of a mattress, the first detection supporting surface is referred to as a bed body, the second detection supporting surface is referred to as a ground, and the secondary bearing part can be a ground mat placed on the ground. The mattress and the at least one floor mat are arranged in parallel along a first direction of the pressure detection mechanism. The first direction here refers to the direction of arrangement of the mattress and the at least one floor mat when using the fiber optic pressure detection system. The first direction is a direction perpendicular to the length direction of the body of the patient lying on the hospital bed, and correspondingly the second direction is the length direction of the body of the patient lying on the hospital bed. And at least one fiber grating sensor arranged in a sparse and dense waveform along the first direction is used for collecting optical signal change data, and the optical signal change data is used for calculating pressure change data corresponding to the optical signal change data, so that the posture change or posture change trend of the current detection object is indicated based on the pressure change data. According to the detection system of the invention, the "potential" out-of-bed behavior is screened out by performing a recumbent posture analysis (secondary analysis) on the "change" data. The double screening mode based on the 'change' data analysis is obviously different from the judgment of 'existence' and 'nonexistence' in the prior art, and the false alarm is effectively reduced. In addition, due to the split design of the main bearing part and the auxiliary bearing part, false alarms are reduced, meanwhile, the real-time performance of alarming can be guaranteed based on the existence of double signals, and the active bed leaving behavior of a guardian can also be judged. Furthermore, the non-uniform arrangement of the fiber grating sensors in both the first and second directions is rather advantageous for overcoming temperature drift. These fiber grating sensors belong to the same product and, when arranged in a known topology, require subtraction operations in order to detect pressure changes. In the planar contact region, a portion having a large pressure tends to have a high temperature close to the body temperature due to close contact, and the temperature tends to decrease as the pressure decreases. This temperature reduction is done in a specific pattern, which can introduce large errors in the pressure analysis. In the invention, a group of virtual concentric rings can be set by taking the maximum pressure as the center, wherein when the pressure change trend is analyzed, the temperature drift is counteracted through the addition and subtraction operation of the fiber grating sensor signals in the same concentric ring, and the temperature drift caused by the temperature change which is difficult to analyze is ingeniously avoided. Although the accuracy of the analysis is not sufficiently high, it is sufficient for the out-of-bed analysis.
According to a preferred embodiment, the arrangement density of the fiber grating sensors on two sides of the main bearing part is greater than that of the fiber grating sensors between two sides of the main bearing part. Compared with the prior art, the intelligent mattress with a uniform arrangement of multiple sensors, such as that proposed by CN104101383B, has a very low accuracy for detecting pressure changes in each area if the number of sensors is small and the sensors are distributed, whereas if the number of sensors is large and the sensors are dense, the amount of data to be processed is increased sharply and the cost is high. In contrast to the arrangement mode in the prior art, the optical fiber pressure detection system provided by the invention adopts a sensor arrangement mode in a density waveform on the basis of synchronously arranging the mattress and the ground mat, and achieves high detection accuracy at low cost.
"compactness" in this application refers to the number of fiber segments arranged in a first direction by the main support (mattress) or the secondary support (mat) as a proportion of the length of the mattress in the first direction. The optical fibers on the mattress and the ground mat are preferably arranged in a wave shape, wherein the density is the density degree between adjacent optical fiber sections when the wave-shaped optical fibers are bent back and forth in a U shape. For example, the sensor arrangement of the present application may take the form of a user's back contact area corresponding to a smaller array density compared to the head and foot contact area. By comparing the pressure variation trend of the back contact area and the head and foot contact area of the user, the accurate monitoring of the posture change of the user lying or lying on the side or getting up can be realized due to the pressure variation trend under the condition that the sensor is arranged in a smaller density on the whole. In a large-area contact area of a body, the detection accuracy of pressure change is improved through smaller arrangement density. According to the method and the device, the sensor arrangement mode with the greater arrangement density on the region where the elbow of the user is located can be adopted, the contact area between the elbow and the contact region is small, and the method and the device can adapt to 'jump-type change' of the point-like pressure points under the monitoring of the sensor with the greater arrangement density.
According to a preferred embodiment, the fiber grating sensors on both sides of the main bearing portion are symmetrically arranged about the central axis of the main bearing portion, wherein the arrangement density of the fiber grating sensors on one side of the main bearing portion has a trend of decreasing and then increasing in the first direction of the main bearing portion, and reaches a minimum value at the central axis of the main bearing portion. The fiber grating sensor is obviously less than the periphery mode in the center of the main bearing part, so that the calculation amount is obviously reduced when the pressure center position is judged and the circle center of a concentric ring is determined, the calculation speed is further improved, and the early warning real-time performance is improved.
According to a preferred embodiment that can also reduce the computation workload, the fiber grating sensors on both sides of the main supporting portion are symmetrically arranged about the central axis of the main supporting portion, wherein the arrangement density of the optical fibers on one side of the main supporting portion has a trend of decreasing and then increasing in the second direction of the main supporting portion and reaches a maximum value in the central region.
A symmetrical arrangement with dense ends and sparse middle is not necessary, but this is instead advantageous in case the second processor is deployed with an artificial intelligence learning plug-in. This is because the head and foot data of the user are obviously different, and at this time, the head and foot can be judged through artificial intelligence learning (for example, the head and foot data are deployed in the second processing device) and the pairing relationship between the new laid mattress and the user is established, so that personalized configuration can be realized more simply. Preferably, the artificial intelligence module of the second processing device is capable of setting a personalized configuration data set for the user upon determining the head and foot, and thereby establishing a new lay mattress-to-user pairing relationship.
By "central axis" is meant in this application a straight line through the centre of gravity of the main bearing with the second direction. The above preferred embodiment is a further limitation of the sensor arrangement distribution in the present application, that is, the arrangement of the density waveform adopted in the present application is not a regular sinusoidal regular density waveform, but an irregular density waveform which is symmetrical about the central axis of the main bearing portion and varies in arrangement density between wave bands. According to the system, the arrangement mode of the sensors with smaller arrangement density is arranged in the region where the back of the user is located, and the arrangement density of the middle region where the back of the user is mainly located is larger than that of the two sides near the back of the user, so that the detection sensitivity of the system to the change rate of the posture of the user during change is improved.
According to a preferred embodiment, the fiber-optic sensor group comprises at least two fiber-optic segments adjacent to each other, wherein the two fiber-optic segments are arranged side by side along the first direction in such a way that the respectively provided at least one fiber-optic grating sensors are arranged offset with respect to each other. Further, under the mode of staggered arrangement, the distance between two adjacent optical fiber sections can be further reduced, the density of the fiber bragg grating sensor is improved, and therefore the probability of misinformation is further reduced while the detection precision of pressure change is improved.
According to a preferred embodiment, the optical fiber pressure detection system at least comprises a controller shell, at least one controller aviation plug is arranged on the outer wall of the controller shell, at least one coupler, at least one light source and at least one fiber grating demodulator are arranged in the controller shell, wherein at least one cable is led out from the main bearing part and the auxiliary bearing part respectively along the respective inner parts of the main bearing part and the auxiliary bearing part, an output plug matched with the controller aviation plug is arranged at the other end of the cable, the output end of the light source is connected with one end of a first fiber sensor group or a second fiber sensor group through the coupler, and the other end of the first fiber sensor group or the second fiber sensor group is connected with the receiving end of the at least one fiber grating demodulator through the coupler.
In the present application, the "first signal" is optical signal variation data generated by a first optical fiber sensor group laid on the mattress in such a manner that at least one optical fiber grating sensor is arranged in a dense-dense waveform along a first direction. The light signal changes are especially due to signal changes caused by pressure fluctuations, which can change along with involuntary basic vital activities of the user, such as breathing and heartbeat, and also can change due to voluntary movements of the user, intervention of nursing staff and vibration of the bed. Such a change would entail a large number of false positives, especially if only the presence or absence is detected according to the prior art. The present invention detects optical signal changes. The task of analyzing the variation trend can be undertaken by a second processing device with cloud access capability; the second processing device is also generally provided with an artificial intelligence module, and the change trend is learned through the artificial intelligence module, so that the typical pressure change style of the user getting out of bed can be learned more quickly and accurately. Under the condition of symmetric density waveform arrangement of the fiber grating sensors in the first direction and the second direction, the four-quadrant diagonal symmetric arrangement form of the fiber grating sensors can be obtained. At this time, the data to be analyzed by the artificial intelligence module is reduced by times, and for the data analysis work only needing to judge the bed leaving state, it is enough to analyze the data of two opposite corners (such as the first quadrant and the third quadrant), and the data of the second quadrant and the fourth quadrant can be used for verification. The area where the area pressure caused by the body is dominant can be defined as the first quadrant, and then the second, third and fourth quadrants are determined counterclockwise. The first quadrant usually has a main trend of the change of the surface pressure, but the change of the pressure appears in a point jump mode. The third quadrant is characterized by a smaller areal pressure. By determining the data grouping rule in this way, the characteristic data can be grasped more simply, and the data volume analyzed by the artificial intelligence module is reduced by geometric progression.
Preferably, in the present application, the "first signal" may also refer to data obtained by further processing the optical signal variation data generated by the first optical fiber sensor group laid on the mattress in such a manner that the at least one optical fiber grating sensor is arranged in a sparse-dense waveform along the first direction, wherein the further processing may be performed by, in particular, a second processing device with cloud access capability. The optical signal variation data (i.e. the first signal) includes sensors corresponding to the density waveform, and based on the arrangement of the sensors of the density waveform, the mattress can also be divided into at least three regions, namely, a left region and a right region which are located on the mattress and close to the end faces on both sides, and a middle region of the mattress. The corresponding fiber grating sensors in each area can be distinguished by numbering each sensor, and then when the optical signal change data collected by the fiber grating demodulators of the first fiber sensor group is obtained, the optical signal change data is further processed to generate the first signal. According to the invention, the three-region division mode can be particularly used in combination with the four-quadrant division mode, and especially when the user behavior habit is not learned in the early stage of use of the mattress, the more rapid learning is realized by using a larger calculation amount, and the safer early warning is also realized. At this time, the false alarm probability is lower, but the false alarm probability is higher in data operation overhead, and the false alarm probability is not a preferred mode for long-term operation. In other words, the optical fiber pressure detection system of the present invention may be provided with an initialization mode with a larger operation amount and a stable operation mode with lower power consumption, wherein the initialization mode jointly adopts the following two analysis modes: the mattress is divided into three areas based on the sensor arrangement mode of density waveforms, and the area which is mainly used for controlling the area pressure caused by the body is defined as a first quadrant, and then a second quadrant, a third quadrant and a fourth quadrant are determined counterclockwise, wherein the stable operation mode only adopts a four-quadrant working mode.
According to a preferred embodiment, the secondary support has a first lateral end face and a second lateral end face perpendicular to the first direction, the first lateral end face being closer to a first detection support face on which the patient is located than the second lateral end face, wherein the first processing device and the second processing device are further configured to perform one or more of the following steps, respectively: when the second signal is acquired for the first time period, determining whether the object currently causing the second signal is the patient or the nursing staff based on the changed orientation of the second signal on the secondary supporting part for the second time period, and further determining whether the current second signal is used for indicating whether the nursing staff is in the position or not or for indicating that the patient is getting out of the bed. The first signal can be used for indicating the posture change or posture change trend of the detected object in the bed, and after the analysis processing is carried out by combining the second signal generated by the fiber grating demodulator corresponding to the second fiber sensor group, whether the posture change or posture change trend is carried out under the non-monitoring condition or under the monitoring condition can be determined, and then whether the alarm needs to be sent out or not is judged based on the analysis processing result. The initialization pattern of the second signal hold formed by these steps may also be suitable for use by specific users with strange behaviors, such as children. Of course, the initialization mode may also be set to an emergency mode for special situations in which the second processing device is absent. At the moment, the user can still be ensured to accurately and timely avoid getting out of bed under the condition of no permission.
According to a preferred embodiment, the fiber optic pressure detection system further comprises a first processing device and a second processing device, the first processing device being communicatively coupled to the second processing device, the first processing device and the second processing device being respectively configured to perform one or more of the following steps: the first processing equipment and the second processing equipment perform information interaction; acquiring a first signal generated by a fiber grating demodulator corresponding to the first fiber sensor group; acquiring a second signal generated by a fiber grating demodulator corresponding to the second fiber sensor group; determining the in-bed condition and the movement trend of the patient based on the first signal representing the change of the lying posture of the patient; the patient's in-bed condition and/or movement trend is combined with a second signal indicative of the caregiver's presence or absence to determine whether to issue a warning and/or alarm. The synchronized analysis of the "first signal" and the "second signal" constitutes an emergency mode of the invention for the absence of a special condition of the second processing device. At the moment, the user can still be ensured to accurately and timely avoid getting out of bed under the condition of no permission.
According to a preferred embodiment of the emergency mode, the changing orientation of the second signal at the second point in time on the secondary bearing part means that the sequence of the at least one fiber grating sensor close to the first lateral face of the secondary bearing part and the at least one fiber grating sensor close to the second lateral face of the secondary bearing part being released in time is given in a second time period immediately after the first time period when a person steps on the secondary bearing part.
According to a preferred embodiment of the emergency mode, the first processing device and the second processing device are further configured to perform one or several of the following steps, respectively: when the second signal is acquired in the first time period, on the basis of the changed orientation, released successively in time, of the at least one fiber bragg grating sensor close to the first side end face of the auxiliary supporting part and the at least one fiber bragg grating sensor close to the second side end face of the auxiliary supporting part in the second time period, and the first signal is not detected in the first time period or the second time period, determining that the object which currently causes the second signal is the patient, and further determining that the current second signal is used for indicating that the patient is getting out of bed.
The invention also discloses an optical fiber pressure detection method realized by utilizing the system, which at least comprises one or more of the following steps: the first processing equipment and the second processing equipment perform information interaction; acquiring, by the first processing device or the second processing device, a first signal generated by a fiber grating demodulator corresponding to the first fiber sensor group; acquiring, by the first processing device or the second processing device, a second signal generated by a fiber grating demodulator corresponding to the second fiber sensor group; determining, by the first processing device or the second processing device, a patient's in-bed condition and movement trend based on the first signal representing changes in patient recumbent posture; combining, by the first processing device or the second processing device, the patient's bed presence and/or movement trend with a second signal indicative of the caregiver's presence or absence to determine whether to issue a warning and/or alarm.
Drawings
FIG. 1 is a simplified overall structural connection diagram of a preferred fiber optic pressure sensing system of the present invention;
FIG. 2 is a cross-sectional view of an optical fiber employed in the present invention;
FIG. 3 is a schematic diagram of the working principle of the fiber grating sensor employed in the present invention; and
fig. 4 is a schematic diagram of the operating principle of the wavelength division multiplexing technique employed in the present invention.
List of reference numerals
1: and (2) a mattress: the floor mat 4: optical fiber grating sensor
5: fiber grating demodulator 6: light source 7: first processing apparatus
8: the wireless module 9: alarm 10: optical fiber segment
11: the coupler 12: controller housing 15: second processing apparatus
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
The invention as shown in fig. 1 provides an optical fiber pressure detection system.
The optical fiber pressure detection system comprises a mattress 1 for placing on a bed body. The mattress 1 is used for the patient to lie, and monitors the prone position of the patient.
The optical fibre pressure detection system comprises two floor mats 2 for placing on the ground. The two ground mats 2 are respectively arranged on the two sides of the bed body. The ground mat is used for medical personnel to trample to whether be located the bed body around monitoring medical personnel. Preferably, a floor mat 2 placed on the ground at a position close to the bed can be used to monitor whether a person is present to assist the patient when the alarm is triggered. The ground mat and the mattress can work together or independently. Other combinations are also conceivable.
The fiber optic pressure detection system includes a controller housing. The controller shell is arranged between the mattress and the ground mat and is used for connecting the mattress and the ground mat. Preferably, at least one controller aviation plug is arranged on the outer wall of the controller shell. At least one cable is respectively led out from the mattress 1 and the ground mat 2 along the inner part of the respective mattress bodies. The other end of the cable is provided with an output plug matched with the aviation plug of the controller. The controller shell is internally provided with a coupler, a light source 6 and a fiber grating demodulator. The output end of the light source 6 is connected with one end of the optical fiber through the coupler, and the other end of the optical fiber is connected with the receiving end of the fiber grating demodulator through the coupler.
As shown in fig. 1, the floor mat 2 and the mattress 1 are provided with a serpentine return arrangement, respectively. Which is located on the mattress 1 for detecting pressure information, in particular pressure changes, exerted on the mattress 1 by a patient located on a patient bed. And is located on the floor mat 2 for detecting information, and possibly also pressure changes, of the pressure exerted on the floor mat 2 by support personnel located around the patient.
The fiber optic pressure sensing system includes a fiber grating sensor 4. According to fig. 1, the fiber grating sensors 4 can be arranged in succession on each of the linearly extending fiber sections in an equidistant manner from one another. In the meandering folding arrangement shown in fig. 1, the routing manner that the two sides are dense and the middle is sparse is adopted, so that the compactness of the fiber grating sensor 4 is also dense and the middle is sparse.
Preferably, the mattress 1 is juxtaposed with at least one floor mat 2 in a first direction of the pressure detection mechanism. The first direction refers to the direction of arrangement of the mattress 1 with the at least one floor mat 2 when using the optical fiber pressure detection system. The first direction is a direction perpendicular to the longitudinal direction of the body of the patient lying on the patient bed. In the first direction of the optical fiber pressure detection system, the density on the mattress 1 and the density on the ground mat 2 are different from each other. Compactness refers to the number of fiber segments 10 arranged in a first direction of the mattress 1 or mat 2 as a proportion of the length of the mattress 1 in the first direction. The mattress 1 and the floor mat 2 are preferably arranged in a wave shape, so that the density is the density between adjacent optical fiber sections 10 in the wave shape of the U-shaped zigzag. The compactness on mattress 1 refers to the proportion of the total number of optical fiber segments 10 arranged in the first direction of mattress 1 to the length of mattress 1 in the first direction. The compactness on the mat 2 refers to the proportion of the total number of optical fiber lengths 10 of the mat 2 arranged in the first direction to the length of the mat 2 in the first direction. The mentioned arrangement of the density wave is similar to the distribution of density wave and density wave which are generated by the common pulse wave or the common density alternation in the sound wave, or the distribution of density wave and density wave which is formed along the wave propagation direction. The waveform refers to an arrangement of curves having a curved vibration frequency other than 0 with respect to a central axis of the mat parallel to the ground and extending longitudinally along the central axis. Preferably, the density waveform refers to an arrangement mode that two ends are dense and the middle is sparse, the dense structure sections at the two ends are arranged at two sides of the cushion which are opposite to each other, and the sparse structure section at the middle is arranged in a region between the two sides of the cushion which are opposite to each other.
According to a preferred embodiment, the fiber grating sensors 4 on both sides of the mattress 1 are arranged symmetrically with respect to the central axis of the mattress 1. Preferably, the central axis of the mattress 1 is perpendicular to the first direction. Further preferably, the rate of change of the density of the fiber grating sensor 4 located at one side of the mattress 1 is larger than the rate of change of the density of the fiber grating sensor 4 located at the central axis of the mattress 1. In the first direction of the optical fiber pressure detection system, the number of the optical fiber grating sensors 4 arranged on the two sides of the mattress 1 is large.
According to fig. 1, a plurality of optical fiber segments 10 are included that are adjacent to each other and have decreasing spacing from the center. Any two optical fiber segments 10 adjacent to each other are arranged in parallel in the first direction in such a manner that the respectively provided at least one fiber grating sensors 4 are arranged offset to each other. Preferably, any two optical fiber spans 10 adjacent to each other are arranged side by side along the first direction in such a manner that the respectively provided at least one fiber grating sensors 4 are arranged opposite to each other. In the staggered arrangement mode, the distance between two adjacent optical fiber sections 10 can be further reduced, and the compactness of the fiber grating sensor 4 is improved. This arrangement is particularly advantageous for dealing with "jump-like changes" in the point pressure caused by the elbow to the mattress, because the trend of the local sharp increase and decrease in pressure becomes gradually smaller from the point pressure as the center, and the "staggered arrangement" is advantageous for analyzing the trend of the pressure change on different optical fiber sections 10, particularly the difference of the trend of the change itself. The method is more favorable for judging the trend of 'jump change', and overcomes the problems in the prior art with lower hardware cost.
According to a preferred embodiment, the floor mat 2 is also provided with at least one first processing device 7 and at least one wireless module 8. The first processing device 7 is connected with the light source 6 and the fiber grating demodulator 5 respectively through lines. The wireless module 8 is configured to support the first processing device 7 to interact with another processing device by means of Wi-Fi, CDM a, other cellular protocols, other radio frequencies, other wireless communication protocols.
Preferably, the first processing device 7 may be a processing chip, an integrated circuit, or a combination of multiple processing chips. The first processing device 7 may be a processing chip such as FPGA, ARM, DSP, CPU, GPU, etc. For example, the first processing device 7 may be a combination of at least one model Krait 400 processing chip based on the ARM architecture. The wireless module 8 includes, but is not limited to, a SIM card processing chip, a WLAN processing chip or other types of wireless processing chips. The electronic components and the circuit chip may be charged by coupling the power module inside the controller housing to an external power source, for example, by removably inserting a power line (e.g., IEEE 1394, Universal Serial Bus (USB), Thunderb olt (Thunderb olt), Lightning (Lightning), Ethernet (Ethernet), etc.) into an interface of the power module. Preferably, the light source 6 may be one of a laser generator, an LED light source or a halogen lamp, and if a laser or an LED light source is used, the central wavelength of light may be 650nm, 660nm, 780nm, 808n m, 830nm, 850nm, 905nm, 940nm, 980nm, 1064nm, 1310nm, 1490nm, 1550nm, 1625nm or 1650 nm. For example, the light source 6 can emit green LED with wavelength of 520-524 nm and power of 60 mw. Preferably, the diameter range is 0.5-20 mm, and the sensing spectrum range is 390-760 nm. The alarm 9 may be a horn. The fiber grating sensor 4 may be a fiber grating sensor 4 also provided on the mattress 1 as provided under publication number CN 204482115U. The fiber grating demodulator 5 can be subdivided into an analog circuit part and a digital circuit part, wherein the analog circuit part has the function of converting strain borne by the Bragg grating (measuring grating) into corresponding electric signals, the digital part converts the electric signals into digital signals which can be directly used by an upper computer, and the digital signals can be wavelength values or strain values and can be demodulated by adopting a single chip microcomputer.
To further clarify the operation of the above-described optical fiber sensing technology, the optical fiber sensing technology applied in the mat is briefly described as follows: first, in basic principle, the fiber sensor will change one or several properties of the light wave it propagates, such as intensity, phase, polarization state, and frequency, according to the change of the tested external environmental parameters. Extrinsic (hybrid) fiber optic sensors use only an optical fiber as the transmission medium for light waves between the device and the sensing element, while intrinsic fiber optic sensors use the optical fiber itself as the sensing element. The heart of the fiber sensing technology according to the present invention is the optical fiber. As shown in fig. 2, the optical fiber is mainly composed of three parts: a core (core), a cladding (cladding) and a cladding (cladding). The cladding can reflect stray light waves emitted by the fiber core back to the fiber core so as to ensure that the light waves have the lowest transmission loss in the fiber core. This function is achieved on the basis that the refractive index of the core is higher than that of the cladding, so that the light wave will undergo total internal reflection as it travels from the core to the cladding. The outermost protective layer provides a protective effect to prevent the optical fiber from being damaged by external environment or external force. And multiple protective layers may be used depending on the strength and protective procedure required. The optical fiber can be a single mode optical fiber or a multimode optical fiber, wherein the specification of the single mode optical fiber is 8-10 μm/125 μm of core diameter/cladding, the specification of the multimode optical fiber is 250 μm of core diameter/cladding 50-100 μm/125, and the typical core diameter is 50 μm, 62.5 μm, 100 μm and 105 μm.
The optical fiber grating sensor (optical grating transducer) adopts the grating-stacked fringe principle to measure the displacement. The grating is formed by densely and parallelly scribing lines at equal intervals on a piece of strip-shaped optical glass, and the scribing density is 10-100 lines/mm. The grating fringe formed by the grating has optical amplification effect and error averaging effect, so that the measurement accuracy can be improved. The sensor consists of four parts, namely a scale grating, an indication grating, a light path system and a measuring system. Scale grating phaseWhen the indication grating moves, the grating stripes with alternate light and dark distributed according to a sine rule are formed. The stripes move at the relative movement speed of the grating and directly irradiate the photoelectric element, a series of electric pulses are obtained at the output ends of the stripes, and digital signals are generated by an amplifying, shaping, direction-sensing and counting system to output so as to directly display the measured displacement. Specifically, as shown in fig. 3, when a broad-spectrum light beam is transmitted to the fiber bragg grating, each small segment of the fiber with the changed optical refractive index reflects only light of a specific wavelength, which is called bragg wavelength, such as λb2n Λ equation, λ bIs the bragg wavelength, n is the effective index of refraction of the fiber core, and Λ is the length of the spacing between the gratings, referred to as the grating period. This characteristic allows the fiber bragg grating to reflect only light waves of one particular wavelength while light waves of other wavelengths are transmitted. Because the bragg wavelength is a function of the length of the spaces between the gratings, a, fiber bragg gratings can be produced with different bragg wavelengths, which enables the use of different fiber bragg gratings to reflect light waves of a particular wavelength. Therefore, the central wavelength of the fiber grating sensor is determined by the effective value of the refractive index of the fiber core and the grating period. Differentiating the above equation to obtain: lambdabAs can be seen from the above equation, when n or Λ changes, the fiber bragg center wavelength shifts. The grating period Lambda is changed due to the fact that the grating is stretched or compressed; in addition, the optical fiber has the elasto-optical effect which determines that the effective refractive index n of the optical fiber changes along with the change of the external stress state. The stress strain induced grating bragg wavelength shift can be expressed by the following equation:
Figure BDA0002423814490000131
wherein P iseThe Tan light coefficient of the fiber bragg grating sensor is referred to, and K is the sensitivity of strain measurement. The process of installing the fiber bragg grating strain sensor is similar to that of installing the conventional electrical strain sensor, and the fiber bragg grating strain sensor has many different kinds and installation methods to choose from, and the package Epoxy-containing type, weldable type, bolt-fixing type, and embedded type. The fiber grating sensor may be a sitting posture detecting device based on a fiber sensor, which is provided in patent document No. CN208259409U issued by maeri makorokfield limited, shenzhen, and the fiber sensor used in the patent document. The adopted optical fiber sensor is a planar optical fiber pressure sensor, the appearance of the optical fiber sensor is similar to a mouse pad, and the optical fiber pressure sensor is especially rectangular or square. The optical fiber sensor is used for detecting the change of an optical signal generated by the pressure change on the surface of the sensor, and the pressure and the optical signal have a unique corresponding relation, namely when the pressure is increased or reduced, the optical signal passing through the optical fiber sensor also changes correspondingly, so that the change of the pressure can be analyzed according to the change of the optical signal; the optical fiber sensor has high sensitivity and can detect fine pressure change. The optical signal may be light intensity, wavelength, modulation frequency, phase, etc. The signal processing unit employed in this patent document is used to analyze the user's sitting posture based on the change of the optical signal generated by the pressure change on the sensor surface detected by the optical fiber sensor. The signal processing unit specifically comprises a photoelectric conversion circuit, a signal amplification filter circuit, an MCU (microprocessor), a light source driving circuit and a light source which are electrically connected in sequence, wherein the photoelectric conversion circuit and the light source are further connected with the optical fiber sensor through optical fiber connectors respectively, and the MCU is electrically connected with the power supply unit, the prompt unit and the wireless communication unit respectively.
The invention also provides a demodulation detection method of the fiber grating sensor. According to the invention, the sensing process is realized by modulating the central wavelength of the fiber bragg grating by the external parameter, and the demodulation process is just opposite and is a process of converting the variable quantity of the reflection wavelength into the information of the external parameter. Since the fiber bragg grating can be implanted at different specific reflection wavelengths, it can be utilized to realize a good wavelength division multiplexing (W DM) technology. As shown in fig. 4, the WDM technique addresses the signal by the characteristic wavelength of the modulation signal of each sensor on the optical fiber bus, injects a broadband light beam into the optical fiber, and obtains the magnitude and position of the measured signal by a filter system, with the characteristic wavelengths of the sensors being different. This feature allows multiple different sensors with specific bragg wavelengths to be daisy chained on a single long distance of individual fibers. Specifically, in fig. 4, the wavelengths of the reflected light of the plurality of fiber grating sensors are λ 1, λ 2, …, λ n, and the fiber grating sensors with different central wavelengths form a sensing network array, which respectively senses the stress strain of each point along the line of the structure to be measured, and changes the wavelengths of the reflected light; the different changed reflected lights are transmitted out of the measuring site through the transmission optical fiber, the size of the wavelength change quantity of the reflected lights is detected through the fiber grating demodulator, and the reflected lights are converted into electric signals; and calculating the stress-strain magnitude of each measuring point of the structure to be measured by the secondary instrument, thereby obtaining the stress-strain distribution condition of the whole structure to be measured. This distribution can be used in the present invention to determine the pressure variation trend.
According to the present invention, wavelength division multiplexing assigns a specific wavelength range for each fiber grating sensor within the available optical spectrum for its use. Due to the inherent wavelength characteristics of the fiber bragg grating, even if the light intensity is lost and attenuated due to bending and transmission of the optical fiber medium in the transmission process, the result measured by the sensor can still be kept accurate. The operating wavelength range of each individual fiber bragg grating sensor and the total wavelength range that can be interrogated by the wavelength interrogator determine the number of sensors that can be attached to a single fiber. Because the wavelength change caused by the strain change is more pronounced than the wavelength change caused by the temperature change, the fiber grating sensor strain sensor is typically assigned an operating wavelength range of approximately 5 nanometers, while the fiber grating sensor temperature sensor is assigned an operating wavelength range of approximately 1 nanometer. However, because the main objective of the invention is to judge the variation trend, the overall similar temperature drift does not cause difficulty to the pressure detection work of the system.
The grating sensor used for detection (interrogation fiber grating sensor) may employ a wavelength-position conversion method incorporating a charge-coupLED led device (CCD) and a fixed dispersive element, or a fast frequency sweep method using a CCD and a tunable fabry-perot filter. Specifically, the method comprises the following steps: a tunable Fabry-Perot filter is used to create a beam of laser light with high energy and capable of being swept quickly to replace the traditional broad-spectrum light source. The tunable laser source concentrates energy within a narrow wavelength range, providing a high energy source with a high signal-to-noise ratio. The high optical power provided by this architecture makes it possible to mount multiple optical channels using a single fiber, which effectively reduces the cost of the multi-channel interrogator and reduces the complexity of the system, making it more advantageous to detect pressure changes. Interrogators based on this tunable laser architecture can scan over a relatively large wavelength range in a narrow spectral band, and a photodetector will measure the laser beam reflected from the fiber grating sensor in synchronization with this scan. When the laser wavelength emitted by the tunable laser coincides with the bragg wavelength of the fiber grating sensor, the optical detector can measure the corresponding response. When the response occurs, the wavelength of the tunable laser corresponds to the temperature and/or strain measured at the fiber grating sensor, and the detection of the pressure change is easy.
The invention adopts the elastic optical fiber as a main sensing device of the optical fiber pressure detection system, the elastic optical fiber can be pre-embedded in the cushion in a special way, the whole cushion is a whole body and can sense the external pressure, the elastic optical fiber is called as an Intelligent material structure (Smart/Intelligent Materials and structures), and the elastic optical fiber has the advantages of two aspects of material and sensing performance. In the aspect of materials, the optical fiber sensing element has small volume and light weight, does not influence the appearance and the volume of the structure, has good compatibility with a matrix material, can ensure the integrity of the structure after being embedded, and has light weight; because the optical fiber is non-conductive and non-heating, and does not generate electromagnetic interference after being embedded, insulation measures are not needed, the optical fiber sensitive element is not sensitive to the electromagnetic interference, has high stability, and can be applied to the severe environment with strong electromagnetic field interference. In the aspect of sensing performance, the optical fiber sensor has the characteristics of high measurement precision and wide measurement range, and is flexible in geometric structure and particularly suitable for a structure with a complex shape. The elastic optical fiber has outstanding elasticity and impact resistance. Also disclosed in patent document CN203028905U is a fiber optic pressure sensing carpet, which also specifically discloses: the elastic characteristic of a special material is utilized to manufacture the optical fiber, and the optical fiber is deformed by utilizing pressure to cause the change of the output light flux; when the pressure is lost, the elastic optical fiber can be restored to the original state, and the effective restoration of the luminous flux is ensured; and can respond repeatedly; the function of optical fiber sensing is realized by combining the existing photoelectric conversion technology; the efficiency of the whole system is higher; the cost performance is higher; because the device participating in induction is a novel elastic polymer optical fiber, the device has the characteristics of no heating, no fear of humidity, safety, reliability and the like.
The invention as shown in fig. 1 provides an optical fiber pressure detection system. It comprises at least a mattress 1 for resting on the bed and at least one ground mat 2 for resting on the ground and connected to the mattress 1 by means of wires. At least one of the floor mat 2 and the mattress 1 is arranged. The mattress 1 and the at least one floor mat 2 are arranged side by side in a first direction of the pressure detection mechanism. In the first direction of the optical fiber pressure detection system, the density on the mattress 1 and the density on the ground mat 2 are different from each other, and the shape on the mattress 1 is defined by density waveforms. Preferably, any two optical fiber segments 10 adjacent to each other are arranged side by side along the first direction in such a manner that the respectively provided at least one fiber grating sensors 4 are arranged offset to each other.
The two ends in the mattress 1 are respectively connected to the light source 6 and the fiber grating demodulator 5 through the coupler 11. The data collected by the fiber grating demodulator 5 are stored and subsequently processed and analyzed by the first processing device 7. In the sensing process, the first processing device 7 controls the light source 6 to emit a broadband light source to enter the fiber bragg grating sensor through the transmission channel, and the sensor embedded in the cushion modulates light waves; the light wave with the external modulation information is reflected by the fiber grating sensor, enters the fiber grating demodulator for demodulation, and is output to the first processing device for data processing and analysis. The first processing device 7 transmits a control signal to the light source 6 to generate light and into it via the coupler 11. The first processing device 7 is also connected to a wireless module 8. The wireless module 8 transmits the information state obtained by the processing of the first processing device 7 to a remote display device such as a smart phone or a tablet computer, and the remote display device processes and displays the signal state transmitted by the first processing device 7. The first processing device 7 is also connected to a power adapter for connection to a wall power supply for power supply. Or a battery for supplying power is separately arranged for supplying power. Preferably, the first processing device 7, the wireless module 8, the light source 6, the coupler 11 and the power adapter or battery are all disposed within a controller housing that is disposed separately from the mattress 1. The housing can be mounted to a hospital bed in a detachably connected manner. Preferably, the controller housing may be internally provided with a sensor controller as disclosed in patent document CN 206910326U.
In the embodiment of the invention, the mattress 1 positioned on the bed body and the ground mat 2 positioned on the ground are arranged at the same time, the turning action or the regional pressure change condition of a user positioned on the bed body can be detected more sensitively through the arrangement of the wiring mode in the mattress 1 and the ground mat 2 and the arrangement mode of the fiber bragg grating sensor 4, and the first processing device 7 transmits the received data to the remote display terminal so as to further analyze and process the data at the remote display terminal and prompt family members or medical staff to check the data.
The invention also provides an alarm component for the optical fiber pressure detection system. The alarm assembly comprises at least one first processing device 7 arranged on the pressure detection mechanism, and at least one fiber grating demodulator 5 and an alarm 9 which are respectively connected with the first processing device 7. The two ends in the mattress 1 are respectively connected to the light source 6 and the fiber grating demodulator 5 through the coupler 11. The data collected by the fiber grating demodulator 5 are stored and subsequently processed and analyzed by the first processing device 7. In the sensing process, the first processing device 7 controls the light source 6 to emit a broadband light source to enter the fiber bragg grating sensor through the transmission channel, and the sensor embedded in the cushion modulates light waves; the light wave with the external modulation information is reflected by the fiber grating sensor, enters the fiber grating demodulator for demodulation, and is output to the first processing device for data processing and analysis. The first processing device 7 transmits a control signal to the light source 6 to generate light and into it via the coupler 11. Wherein the first processing device 7 receives and accumulates the demodulated signal output by the fiber grating demodulator 5. The first processing device 7 determines whether or not the warning threshold is reached based on the intensity of the demodulated signal. The early warning threshold value can be determined according to factors such as the area of the sole of the foot, weight pressure and the like. A digital signal 1 is generated based on the demodulated signal reaching the early warning threshold. After the digital signals are gathered to the first processing device 7 or the logic processing chip, whether the early warning value is reached is judged according to the accumulation amount of the digital signals. Preferably, the alarm assembly comprises at least one wireless module 8 arranged on the pressure detection mechanism, and the wireless module 8 sends wireless signals outwards through a miniature antenna. The first processing device 7 comprises at least a logic processing chip. A remote display terminal operated by a family member or a medical person issues an alarm prompt in response to a wireless signal sent by the radio module, which can be used to display a ward, floor, bed number, patient name, etc. corresponding to each alarm assembly. The logic processing chip and the wireless transmission chip are SIM card processing chips, WLAN processing chips or other wireless processing chips. The mattress 1 can be set to the specifications of 80-90 cm width and 60-90 cm length based on the specifications of 80-90 cm width and 180-210 cm length of the common hospital bed. The floor mat 2 may be set to have a width of 10 to 40cm and a length of 120 to 210 cm. Preferably, the mattress 1 may be of a 90cm width and 60cm length format, and the mat 2 may be of a 20cm width and 120cm length format. The regions of the mattress 1 which occupy the width 3/8 of the mattress 1 on both sides in its longitudinal direction are divided into two regions of higher density, the region between which is the middle region of lower density. In each case 30(6 × 5) fiber grating sensors 4 are arranged in the two side regions, 20 (4 × 5) fiber grating sensors 4 are arranged in the middle region, and 40(4 × 10) fiber grating sensors 4 are arranged on the floor mat 2. When no pressure sense is detected on the floor mat 2 or at least 5 accumulated quantities are not collected on the floor mat 2, no family members or medical staff are around the hospital bed, and therefore when the accumulated quantities on the mattress 1 processed by the first processing device 7 or the logic processing chip exceed 15, the beeper gives an alarm prompt. When the floor mat 2 detects pressure or collects at least 5 accumulated quantities, it indicates that family members or medical staff are around the hospital bed, and the alarm is cancelled.
In the actual nursing process of the patient, since the rising behavior of the patient is usually monitored by judging whether the pressure changes exist in the prior art, the situations causing the relevant pressure changes include two situations that the patient tries to rise without assistance and the patient rises with assistance, the former causes a correct alarm, and the latter causes an unnecessary false alarm. The above is also one of the reasons for the high false alarm rate of the conventional nursing pad. Aiming at the problems in the prior art, the split type optical fiber pressure detection system for nursing provided by the invention can not only give correct alarm when a patient tries to get up without assistance, but also can monitor the corresponding pressure change caused by the assistant when the patient gets up with assistance because the assistant needs to stand to two sides of the bed body to assist the patient to get up, so that the alarm can be turned off based on the pressure change collected by the floor mat 2 even if the pressure change collected by the mattress 1 meets the alarm condition, thereby reducing the false alarm rate and improving the use feeling of doctors and patients.
According to a preferred mode, the fiber optic pressure detection system includes a first processing device and a second processing device 15. The first processing device 7 is provided in the controller case. Which may be a processing chip, an integrated circuit, or a combination of multiple processing chips. The second processing device 15 may be a smart device such as a smartphone, smart band, tablet or other portable smart device, or its second processing device 15 may also be a remote server. The various processing devices may communicate wirelessly using bluetooth, Wi-Fi, CDMA, other cellular protocols, other radio frequencies, or another wireless communication protocol, etc. The first processing device 7 is communicatively coupled to the second processing device 15, the first processing device 7 and the second processing device 15 being configured to perform one or several of the following steps, respectively:
The first processing device 7 performs information interaction with the second processing device 15;
acquiring a first signal generated by a fiber grating demodulator corresponding to the first fiber sensor group;
the patient can be confirmed to be located on the bed body based on the first signal, and the size and the position of the detected signal determined based on the fiber grating demodulator can correspond to the position of the triggered fiber grating sensor on the mattress 1, namely the in-bed condition of the patient at the moment.
Under the condition that the number of the triggered fiber grating sensors 4 close to the side end face of the mattress 1 and the stress condition rise synchronously, the patient is determined to try to get up or turn over laterally at the moment. Under the condition that the number of the triggered fiber bragg grating sensors 4 close to the side end face of the mattress 1 is in a change trend of increasing firstly and then reducing greatly, the patient can be determined to try to get up laterally at the moment;
under the condition that the number of the triggered fiber bragg grating sensors 4 close to the side end face of the mattress 1 is in the change trend of firstly increasing and then changing in small amplitude, the patient can be determined to turn over only laterally at the moment.
Upon determining that the patient is attempting to rise sideways, it is then determined whether the caregiver is in position based on the second signal. It may be determined that a person is at the bedside based on the second signal, which may be that the patient has got out of bed to stand at the bedside or that a medical staff is standing at the bedside to assist the patient in getting up.
Acquiring a second signal generated by a fiber grating demodulator corresponding to the second fiber sensor group when it is determined that the patient is attempting to rise sideways, and determining that medical staff is currently standing at the bedside to assist the patient in rising if a valid second signal on the floor mat 2 is acquired while it is determined that the patient is attempting to rise sideways;
when the patient is determined to try to get up laterally, acquiring a second signal generated by a fiber bragg grating demodulator corresponding to the second fiber optic sensor group, if the patient is determined to try to get up laterally and a valid second signal located on the floor mat 2 is not acquired, determining that the patient is trying to get up independently at the moment and the danger is high, indicating an alarm 9 to give an alarm to the patient, warning the patient to return to the hospital bed, simultaneously sending alarm information to corresponding equipment held by medical staff, determining that the patient lies back to the hospital bed again when the first signal is monitored, and canceling the alarm;
if a second signal generated by the fiber grating demodulator corresponding to the second fiber grating sensor group is acquired after the patient tries to rise sideways, and the change direction of the second signal is to leave towards the direction away from the hospital bed, namely when the second signal is acquired for the first time period, the patient is indicated to leave the hospital bed independently based on the change direction that at least one fiber grating sensor close to the first side end face of the floor mat and at least one fiber grating sensor close to the second side end face of the floor mat are released successively in time, and the alarm 9 is indicated to give an alarm to the patient and the surrounding people, wherein the alarm is more loud than the alarm;
If a second signal generated by the fiber grating demodulator corresponding to the second fiber sensor group is acquired after the patient is determined to try to rise up laterally, and the change of the second signal points to a direction other than away from the sickbed, it indicates that the medical staff is located around the sickbed to assist the patient correspondingly, and the alarm of the alarm 9 is cancelled. Preferably, the direction of the change of the second signal refers to that the sensor acquiring the second signal reaches the detection threshold intensity gradually increases from the side close to the bed to the side far away from the bed (such as the patient himself), or gradually increases from the side far away from the bed to the side close to the bed (such as the medical staff).
It should be noted that the above-mentioned embodiments are exemplary, and that those skilled in the art, having benefit of the present disclosure, may devise various arrangements that are within the scope of the present disclosure and that fall within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents.

Claims (4)

1. A fiber optic pressure detection system comprising at least:
a main bearing part (1) which is arranged on the first detection supporting surface and a first optical fiber sensor group is laid in the main bearing part,
at least one auxiliary bearing part (2) which is arranged on the second detection supporting surface and a second optical fiber sensor group is laid in the auxiliary bearing part,
the first optical fiber sensor group and the second optical fiber sensor group respectively comprise at least one fiber bragg grating sensor (4),
it is characterized in that the utility model is characterized in that,
the main supporting part (1) and the at least one auxiliary supporting part (2) are arranged in parallel along a first direction of the pressure detection system, the first fiber sensor group is laid on the main supporting part (1) in a mode that at least one fiber grating sensor (4) is arranged in a sparse and dense waveform along the first direction, the fiber grating sensor (4) is used for detecting optical signal changes caused by the changes of the lying posture of a user on the surface of the main supporting part, and the possibility that the user gets out of bed from the lying posture is determined based on the pressure changes obtained by the optical signal changes;
the arrangement density of the fiber bragg grating sensors (4) positioned on two sides of the main bearing part (1) is greater than that of the fiber bragg grating sensors (4) positioned between two sides of the main bearing part (1), wherein in four quadrants taking the center of the main bearing part (1) as an origin, the arrangement densities of the four quadrants are not only in mirror symmetry with each other, but also in axial symmetry with each other;
The arrangement density of the fiber bragg grating sensors (4) positioned on one side of the main supporting part (1) is in a variation trend of firstly decreasing and then increasing in the first direction of the main supporting part (1) and reaches a minimum value at the central axis of the main supporting part (1), so that the arrangement density of the fiber bragg grating sensors (4) higher than the center is formed on two sides of a lying patient;
the at least one processor is configured to:
acquiring a first signal reflecting pressure variations generated by a fiber grating demodulator (5) corresponding to the first fiber sensor group;
acquiring a second signal reflecting pressure variations and/or pressure values generated by a fiber grating demodulator (5) corresponding to the second fiber sensor group;
determining the in-bed condition and the movement trend of the patient based on the first signal representing the change of the lying posture of the patient;
combining the patient's in-bed condition and/or movement trend with a second signal indicative of the caregiver's presence or absence to determine a likelihood of the user moving from a lying position to an out-of-bed position based on pressure changes analyzed from the first and second signals;
under the condition that the number of the triggered fiber bragg grating sensors (4) close to the side end face of the main supporting part (1) and the stress condition are synchronously increased, the patient is determined to try to get up or turn over laterally, wherein under the condition that the number of the triggered fiber bragg grating sensors (4) close to the side end face of the main supporting part (1) is in a change trend of increasing firstly and then reducing greatly, the patient can be determined to try to get up laterally;
Under the condition that the number of the triggered fiber bragg grating sensors (4) close to the side end face of the main supporting part (1) is in a change trend of increasing firstly and then changing by a small amplitude, the patient can be determined to turn over only laterally at the moment;
upon determining that the patient is attempting to rise sideways, then determining whether the caregiver is in position based on the second signal, based on which it may be determined that a person is at the bedside, which may be that the patient has fallen off the bed standing at the bedside or that a healthcare worker is standing at the bedside to assist the patient in rising;
acquiring a second signal generated by a fiber grating demodulator corresponding to said second set of fiber optic sensors when it is determined that the patient is attempting to rise sideways, determining that medical personnel is currently standing at the bedside to assist the patient in rising if a valid second signal on the secondary support (2) is acquired while it is determined that the patient is attempting to rise sideways;
when the patient is determined to try to get up laterally, acquiring a second signal generated by a fiber bragg grating demodulator corresponding to the second fiber optic sensor group, if a valid second signal positioned on the secondary supporting part (2) is not acquired while the patient is determined to try to get up laterally, determining that the patient is trying to get up independently at the moment, indicating an alarm (9) to give an alarm to the patient, warning the patient to return to a hospital bed, sending alarm information to corresponding equipment held by medical staff, determining that the patient lies back to the hospital bed again when the first signal is monitored, and canceling the alarm;
If a second signal generated by a fiber grating demodulator corresponding to the second fiber sensor group is acquired after the patient tries to rise sideways, and the change direction of the second signal is departing towards the direction far away from the hospital bed, namely when the second signal is acquired in the first time period, the patient is indicated to leave independently based on the change direction released in time sequence between at least one fiber grating sensor close to the first side end face of the auxiliary supporting part and at least one fiber grating sensor close to the second side end face of the auxiliary supporting part in the second time period, and an alarm (9) is indicated to send an alarm to the patient and the surrounding people, wherein the alarm volume is larger than the alarm volume;
if a second signal generated by the fiber bragg grating demodulator corresponding to the second fiber optic sensor group is acquired after the patient is determined to try to get up laterally, and the change direction of the second signal is not away from the direction of the sickbed, the fact that the medical staff is located around the sickbed to assist the patient correspondingly is shown, and the alarm of the alarm (9) is cancelled;
The change direction of the second signal means that the collected second signal reaches the detection threshold intensity, and the second signal gradually increases from one side close to the bed body to one side far away from the bed body, or gradually increases from one side far away from the bed body to one side close to the bed body.
2. The fiber optic pressure sensing system of claim 1, wherein the fiber optic sensor group comprises at least two fiber optic segments (10) adjacent to each other, wherein the two fiber optic segments (10) are juxtaposed in the first direction in such a manner that the respectively provided at least one fiber grating sensor (4) is staggered with respect to each other.
3. The optical fiber pressure detection system according to claim 2, characterized in that the optical fiber pressure detection system at least comprises a controller housing (12), at least one controller aviation plug is arranged on the outer wall of the controller housing (12), and at least one coupler (11), at least one light source (6) and at least one fiber grating demodulator (5) are arranged in the controller housing.
4. The fiber optic pressure detection system of claim 3, further comprising a first processing device (7) and a second processing device (15), the first processing device (7) being communicatively coupled to the second processing device (15), the first processing device (7) or the second processing device (15) being configured to determine a patient's bed presence and movement tendency and/or presence or absence of a caregiver based on at least one fiber grating sensor (4).
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