JP2006223650A - Bed, sit-up detecting device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technologies for detecting the sitting-up motion of a user from a bed while discriminating the motion from other motions. <P>SOLUTION: The bed with a fence comprises a sensor disposed to detect at least the force of pulling the fence to the bed side, a data acquisition means for acquiring data on the force based on signals outputted from the sensor, a recording means for storing reference data to be used for determining the bed user's sitting-up motion, and a determining means for determining whether the user sits up or not by comparing the data acquired by the data acquisition means and the reference data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for detecting that a user sleeping on a bed is going to get up using a bed fence.

  In a facility such as a hospital, a bed is generally provided with a fence in order to prevent a patient from leaving the bed or to fall from the bed. Various types of beds equipped with such a fence are commercially available, for example, a plug-in type in which the fence is simply inserted into the bed body (see Patent Document 1), or a fold that can fold the fence. There is a formula (see Patent Document 2 and Patent Document 3). In general, the fence is removable, and the fence is attached to the insertion port of the bed body.

  When a patient gets out of a bed with a fence in a facility such as a hospital, the caregiver usually folds the fence, but depending on the patient the caregiver does not see the fence There is a case where it tries to get over the bed and get off the bed, in which case there is a risk of falling. In addition, some patients may try to get out of the bed on their own, although there is a need for assistance in getting on and off the bed, in which case there is a risk of falling or falling.

  Since caregivers cannot always look at a patient, it is a challenge to automatically detect that the patient is about to get out of bed with a fence.

  As a prior art aiming at solving the above-mentioned problems, first, a cylindrical contact sensor was attached to the handrail portion at the top of the bed fence, and the patient grasped the handrail via the contact sensor. There is known a system that notifies a nurse call or the like when it is detected (for example, http://www.technosj.co.jp/Fukushi/Haikai/Frame/TC.htm, January 2005 search).

  Secondly, Patent Document 4 discloses a technique aimed at preventing an accident in which a cared person on a bed body falls while trying to get out of bed. In this technology, a sensor for detecting the downward load of the fence is provided at the attachment portion of the fence in the bed body, and it is determined that the cared person is going to leave the floor when the load exceeds a predetermined discrimination threshold. .

Third, there is a commercially available sensor that detects a mat-type pressure generally called a bed leaving sensor, which is laid on or next to the bed. The bed leaving sensor is laid around the shoulder and waist of the patient, and has a function of detecting that the patient is off the bed and notifying the patient by a nurse call or the like.
Japanese Patent Laid-Open No. 10-033596 JP 2000-245781 A JP 09-206338 A JP 2003-190227 A

  In the first prior art described above, when the futon gets on the contact sensor, when the medical device is temporarily placed on the handrail, when a person other than the patient touches the handrail, the patient does not use the handrail. There is a problem that the contact sensor reacts even in cases other than gripping and erroneous notification is likely to occur. In the first prior art, since it has a cylindrical shape, it can be installed only on the upper part of the frame-shaped fence and cannot be installed on the vertical bar part or curved part of the fence, or the contact sensor itself has a thickness. For this reason, when installed on a folding fence, there is also a problem of interference with a bed mat or the like.

  Moreover, in said 2nd prior art, a cared person detects the load which pushes a fence downward, and determines bed leaving. However, the timing when the cared person pushes the fence downward corresponds to the timing when the cared person is about to get over the bed after the cared person gets up from the bed, and it may fall immediately after that. . Therefore, even if the caregiver is notified of being out of bed by the second prior art, there is a problem that the caregiver's rushing is not in time, and there is a possibility of falling, which is not sufficient as a technique for preventing a fall accident. .

  Furthermore, in the third prior art described above, it is detected that the patient's body has left the bed and pressure is no longer applied to the sensor, and rising is determined. However, since the timing when the patient gets up from the bed corresponds to the time immediately before the patient tries to get out of the bed, the patient may fall down. Therefore, as in the case of the second conventional technology, even if the caregiver is notified that the getaway sensor is determined to be getting out of bed, the caregiver will not be able to rush in time, and there is a possibility of falling or falling. There is a problem that the technology is not sufficient. In addition, since the appropriate position for installing the sensor differs depending on the individual, skill is required for sensor installation. Furthermore, when the installation position is inappropriate, there is a problem that the sensor reacts to turning over and the like, and erroneous notification is likely to occur.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a technique for detecting an operation in which a bed user gets up from a bed separately from other events.

  The above-described problem is a bed provided with a fence, wherein the force data is obtained based on a sensor arranged to detect at least a force pulling the fence toward the bed and a signal output from the sensor. The acquisition means for acquiring, the recording means for storing the reference data used for determining the rising of the user of the bed, the data acquired by the acquiring means, and the reference data are compared, It can be solved by a bed characterized by having determination means for determining whether or not.

  Further, the present invention is a rising detection device for detecting a rising motion of a user of a bed provided with a fence, which is output from a sensor arranged to detect at least a force for pulling the fence toward the bed. The acquisition means for acquiring the force data, the recording means for storing the reference data used for determining rising, the data acquired by the acquisition means, and the reference data are compared based on the received signal Thus, it can be configured as a rising detection device characterized by having a determination means for determining whether to get up.

  Further, the sensor is a plurality of sensors attached to a plurality of surfaces of the support column of the fence, and the determination means includes the magnitude and direction of the force as the reference data, and signals from the plurality of sensors. It may be determined whether or not the person gets up by comparing the magnitude and direction of the force obtained from the above. Moreover, you may further provide the process execution means which performs the process according to the determination result by the said determination means.

  The present invention can also be configured as a program that causes a computer to realize the function of the rising detection device.

  According to the present invention, since at least the force of pulling the fence toward the bed is detected, the bed user gets up from the bed, that is, the action at an earlier stage than the timing when the user gets over the fence or the upper body gets up from the bed. Can be detected separately from other events.

  Embodiments of the present invention will be described below with reference to the drawings.

(System configuration)
FIG. 1 shows a system configuration diagram according to an embodiment of the present invention. As shown in FIG. 1, the system according to the present embodiment determines a bed 5 provided with a sensor in a fence portion, and the rising of a bed user based on a signal from the sensor, and executes processing according to the determination result. Determination device 7 (also referred to as a rising detection device). Furthermore, an external device 9 that is a counterpart to which the determination device 7 notifies the determination result is connected to the determination device 7 via a network. FIG. 1 also shows the definition of directions used in the following description. That is, when the bed user sleeps, the head direction is upward, the foot direction is downward, the inside of the bed is viewed from the fence as viewed from the user in the bed, and the outside of the bed is viewed from the user in the bed. Is the back direction. In FIG. 1, the illustration of the front fence is omitted. Moreover, the determination apparatus 7 may be provided in the main body of the bed.

  The sensor attached to the fence can detect at least the force that the user of the bed pulls the fence forward. In this embodiment, by detecting the pulling force at least toward the front, the user gets up by grabbing the fence post, etc., which is an operation at an earlier stage than when the user gets over the fence or the upper body gets up from the bed Is detected.

(Sensor arrangement)
FIG. 2 is a diagram illustrating an example of the arrangement positions of the sensors on the fence. Note that the bed shown in FIG. 2 is of a type that is used by inserting a fence composed of an upper member of the fence and a column supporting the same into an insertion port of the bed body.
FIG. 2 shows examples of three types of arrangements, and it is sufficient that at least one type of sensor is provided. The sensor arrangement position 1 is a position where the pressure sensor is attached to the side surface of the column at the joint portion between the upper member of the fence and the column. The sensor arrangement position 2 is for attaching the pressure sensor to the side surface of the support column at the joint portion between the bed main body and the fence. The sensor arrangement position 3 is for attaching the strain sensor to the side surface near the center of the fence support. The sensor arrangement position 1 is effective when the upper member of the fence is connected to the bed main body via another member (for example, a side plate on the upper side of the bed).

  FIG. 3 is a horizontal cross-sectional view of the column with the sensor attached to the column. The direction is common in FIG. 3 as shown in FIG. As shown to Fig.3 (a), the force of all the directions on a horizontal surface is detectable by attaching the pressure sensors 11-14 to each side surface of a support | pillar with a square cross section. If only the force pulling in the front direction is detected, as shown in FIG. 3B, the pressure sensor 11 may be attached only to the front side surface of the support column. Further, in the case of a column support instead of a quadrangle, for example, it can be attached as shown in FIGS. 3 (c) and 3 (d). Moreover, you may attach a pressure sensor not to the support | pillar side but to the upper member side of a fence if it is the sensor arrangement position 1, and to the fence insertion port side of the bed main body if it is the sensor arrangement position 2. A cross-sectional example in that case is shown in FIG. As the pressure sensor, a thin pressure-sensitive conductive rubber, a piezo sensor, or the like can be used.

  FIG. 3F is a horizontal cross-sectional view of the column with the strain sensor attached to the column. As shown in FIG. 3 (f), the strain sensors 15 and 16 may be attached to two surfaces, or may be attached to four surfaces in order to detect all directions. As the strain sensor, a commercially available strain gauge can be used. In the strain sensor, the direction of the strain (inside and outside) and the magnitude of the strain are obtained by using the difference between the output values of the two strain sensors arranged so as to face the column, and the magnitude and direction of the force based on the strain direction. Can be obtained.

  For example, the pressure sensor or the strain sensor may be attached to one support column that is likely to be gripped by the bed user, or may be attached to a plurality of support columns around the support column. In addition, when attaching to one support | pillar, even if a user grasps the vicinity of the support | pillar instead of the support | pillar, it is possible to detect force.

  Further, even in cases other than the type of fence as shown in FIG. 2, it is possible to attach a pressure sensor as long as it is a part where the bed body and the fence are attached and a force acts on the bed body from the fence. . Furthermore, even if it is a fence which does not have such a part, a pressure sensor can be incorporated in the junction part etc. in the structure of a fence. Further, by using a strain sensor, it is possible to detect force even in the case of a fence without a joint portion.

(How to get up)
Next, a method for determining the rising will be described with reference to FIG.

  FIG. 4 is an image diagram showing, in time series, the force applied to the fence when the user of the bed gets up. In addition, the figure is an image figure for showing an example to the last.

  When the bed user gets up, the user first grabs the fence post and pulls his body towards the fence. Accordingly, at this time, a pulling force mainly acts on the fence (timing 1). The user then grabs the column and moves his body down the bed. That is, at this time, a force that pushes the fence upward mainly acts (timing 2). Thereafter, the user performs an operation of raising the upper body by grasping the support post of the fence or the upper member of the fence. Accordingly, at this time, a force pulling mainly toward the front acts on the fence (timing 3).

  As described above, when the user gets up, at least the force that pulls the fence forward acts, so the user will get up when it is detected that the fence is pulled with a force larger than the predetermined force in the forward direction. Can be determined. In the example of FIG. 4, by setting a predetermined force as the threshold value 1, it is possible to detect the first action of getting up.

  Also, by investigating in more detail the direction of the force acting on the fence when getting up, a threshold for the force in that direction is set, and when a force greater than the threshold is detected in that direction when detecting motion It is also possible to determine that you are getting up. Note that the direction of the force can be easily calculated by calculating the vector sum of the forces in the normal direction of the installation surface of each sensor if a pressure sensor is arranged on each side as shown in FIG. is there.

  Further, as described above, when the force greater than the threshold value is obtained in the predetermined direction, it is determined that the signal is rising, and when the force larger than the threshold value in the predetermined direction continues for a predetermined time, It may be determined that there is. In this case, for example, it is possible to prevent erroneous determination due to momentary application of force even though it is not a rising motion.

  Moreover, you may detect a rising from the time change of the force and direction which are applied to a fence. For example, the transition of force at the time of rising as shown in FIG. 4 is converted into data by conducting an experiment or the like in advance, and the transition of data obtained from the sensor and the data recorded in advance at the time of detection of rising is detected. A close correlation value is taken, and when the correlation value is equal to or greater than a certain value, it can be determined that the signal has risen.

  In the case of using the time change of FIG. 4, for example, a force having a magnitude of 1 or more is applied in the forward direction, and a force having a magnitude of 2 or more is applied in the upward direction after a predetermined time has elapsed. Further, after a predetermined time has passed, if a force having a magnitude of the threshold value 3 or more is applied again in the forward direction, it may be determined that the person is getting up.

  Furthermore, it is possible to detect a rising motion using an HMM (Hidden Markov Model) that receives the direction in which the force is applied and the magnitude of the force.

  Also, rather than simply comparing the magnitude of the force, the force integral value is compared with the corresponding reference data, and in the case of a user who is characterized by a change in force, the force vector The determination may be made by comparing the differential value (change) with the corresponding reference data.

(Judgment device)
Next, a determination apparatus that performs determination based on the above determination method will be described.

  FIG. 5 shows a functional configuration diagram of the determination apparatus. The determination device includes a recording unit 21 that stores various data, a sensor signal acquisition unit 23 that receives input of signals from each sensor and outputs the data as force data to the recording unit 21, and is recorded in the recording unit 21. It has the determination part 25 which reads sensor data, detects a rising motion, and outputs a determination result, and the process execution part 27 which performs the process based on a determination result. The determination device may be realized using a logic circuit, or may be realized as a computer including a circuit that receives a signal from a sensor and a program for performing a determination process. Further, the program can be recorded on a recording medium such as a CD-ROM or a memory, or can be provided through a network.

  The recording unit 21 includes a determination reference recording area 211 and a sensor data recording area 212 as shown in FIG. In the determination reference recording area 211, reference data for determination is recorded. For example, in the case shown in FIG. 3B, when the rising is determined only by the magnitude of the forward force, the threshold A of the force is recorded. Further, when the determination is made based on the magnitude of the force and its duration, the threshold B and the time are recorded. Further, when the rising is determined by the direction of the force and the magnitude of the force in the direction, a threshold value C of the direction and the magnitude of the force is recorded. Further, in the case of performing determination based on time change, the direction and force for each time are recorded as time series data.

  Further, as shown in FIG. 6, each of the above data can be stored in each region according to the determination method, and the determination unit 25 can select which region of data to use. When the direction of the force is included in the determination criterion, a range in which it can be determined that the direction of the force matches the criterion is determined in advance and recorded as an allowable error range of the force direction.

  As a method for recording data in the determination reference recording area 211, there are a manual setting method and an automatic setting method.

  As an example of setting manually, “magnitude of force”, “direction of force”, “length of time”, etc. are prepared in advance and input to the determination device. Instead of specifying such a specific value, only the weight of the user may be input. In this case, the determination device sets the magnitude of the force appropriate for the weight as a reference value. Further, the direction may be input in the form of a ratio of forces applied in the main direction.

  As an example of the automatic setting, the user is caused to get up and, for example, about 80% of the maximum value of the data obtained as the force in the front pulling direction is recorded as a threshold value. Further, by recording force data including a direction in time series, it is possible to use as reference data (teacher data) at the time of making a determination based on temporal changes in the direction and magnitude of the force. When there are a plurality of teacher data, the average value of the teacher data, the median value, etc. are used. Furthermore, when using an HMM, learning of the HMM is performed using teacher data.

  Now, in the sensor data area 212 of the recording unit 21, force data for each sensor output from the sensor signal acquisition unit 23 is recorded in association with time at regular time intervals. In the case of the force obtained from the strain sensor, the magnitude and direction of the force are recorded. For example, as shown in FIG. 3 (f), when strain sensors are arranged at the front and back, the magnitude of the force and the force acting in the front direction or the force acting in the back direction are applied. Force is recorded.

  These recording methods are examples, and may be recorded as a vector including the direction of force obtained from a plurality of sensors, or may be recorded with a value closer to the sensor signal itself (distortion itself, voltage, etc.). Good. The sensor data recorded in association with the time can be recorded only for a certain length of time, and the previously recorded data can be deleted over time.

(Processing of judgment part)
Hereinafter, with reference to the flowchart of FIG. 7, the process of the determination unit 25 in the case where the rising detection is performed using the two strain sensors facing each other as illustrated in FIG. The example of FIG. 7 is an example in the case where the value of distortion for each sensor is recorded in the sensor data area 212.

  The determination unit 25 reads the latest data of the two strain sensors from the sensor data area where the sensor data is sequentially recorded (step 1). Then, the difference between the two data is calculated, and the force and the direction of the force are calculated (step 2). By predetermining which side of the sensor data is to be subtracted from which side of the sensor data, the direction of the force can be determined by the sign of the difference result, and the magnitude of the strain and the fence with the strain sensor are measured in advance. The magnitude of the force can be calculated from the obtained coefficient.

  The determination unit 25 determines whether or not the direction of the force is the front direction of the bed (step 3). If the direction is the front direction, the threshold value obtained from the determination reference recording area 211 and the force obtained from the sensor output are determined. The magnitude is compared (step 4), and if the magnitude of the force is larger than the threshold value, it is determined that the user gets up and the result is output (step 5). If the direction is not the front direction in step 3, or if the magnitude of the force is less than or equal to the threshold value in step 4, the sensor data to be recorded next is acquired and the above processing is executed again.

  Next, the processing of the determination unit 25 in the case where the rising determination is performed using the four pressure sensors as illustrated in FIG. 3A will be described with reference to the flowchart of FIG.

  First, sensor data of four sensors is acquired from the sensor data area (step 11). Then, the direction of force is calculated from each sensor data (step 12). Thereafter, it is determined whether or not the direction of force is within a predetermined range with respect to the direction of force of the criterion (step 13). If it is within the predetermined range, it is next determined whether or not the magnitude of the calculated force in the direction of the force is greater than a reference threshold (step 14). If it is larger than the threshold value, it is determined that the user gets up, and the determination result is output (step 15). In the case of No in the above step 13 and step 14, the above processing is executed again based on the next sensor data. Even when four strain sensors are used, the determination can be performed in the same manner as the flow of FIG.

  Next, a case where it is determined that the force has risen when the force is greater than the threshold value for a predetermined time length will be described with reference to the flowchart of FIG. 9 taking the strain sensor as an example.

  First, the timer is reset (step 21). Subsequently, the data of the two strain sensors are read (step 22). Then, the difference between the two data is calculated, and the force and the direction of the force are calculated (step 23). It is determined whether or not the direction of the force is the front direction of the bed (step 24). If the direction is the front direction, the threshold value acquired from the determination reference recording area 211 and the magnitude of the force obtained from the sensor output are compared. (Step 25) If the magnitude of the force is greater than the threshold, it is determined whether the timer has reached a predetermined time (Step 26). If it is not in the front direction in step 24, or if the magnitude of the force is less than or equal to the threshold value in step 25, the timer is reset, the next recorded sensor data is acquired, and the process is performed again.

  If the predetermined time has not been reached in step 26, the next sensor data is acquired and the processing from step 22 is performed again. If it is determined in step 26 that the predetermined time has elapsed, it is determined that the user is up and the result is output (step 27).

  Next, an example in which determination is performed using time-series sensor data will be described with reference to FIG. In the following description, it is assumed that “force” includes a direction.

  First, a force is calculated (step 31), and it is determined whether or not the calculated magnitude of the force is larger than a predetermined value compared with a predetermined reference value (step 32). This is for determining whether the user has started the operation. When the value is larger than the predetermined value, the difference between the force data and the first data of the time-series data serving as a criterion is obtained and added to the accumulated value (0 at first) (step 33). Then, it is determined whether or not a predetermined time has elapsed for the rising motion (step 34). If not, the force is obtained from the next sensor data (step 35), and the processing of steps 33 and 34 is performed. I do. In step 33, time data corresponding to the current time is used as the reference data.

  When the predetermined time has elapsed, the accumulated value is compared with a predetermined reference value (step 36), and if the difference is within the predetermined range, it is determined that it is rising, and the result is output (step 37). In particular, there are various types of processing for performing determination using time-series data, and the above processing is only an example.

(Processing process processing)
When it is determined that the user has risen as described above, for example, the process execution unit 27 notifies the nurse call center device that there has been a rise. As a result, a report is made to a nurse or the like. Moreover, it can also be comprised so that it can record on an external recording device and can be browsed as historical information.

(About effect)
As described above, by using the sensor arrangement and determination method described in this embodiment, when a futon or other article is hung on the fence, or when another person touches the handrail, the rising motion Identification becomes possible. This is because when a futon or other article is hung on the fence, or when another person touches the handrail, a force is mainly applied from above the fence. This is because rising force is determined by detecting a pulling force in the forward direction.

  Also, especially when the bed user repels the futon and presses the futon against the fence, a force opposite to the direction of pulling the fence acts on the fence, so the rising and the bedding of the futon are also distinguished. it can. In addition, even when a device or nurse touches the fence, the direction and magnitude of the force (if the judgment function includes time change, the time change) is also different. Can be distinguished.

  Furthermore, in the technique of the present embodiment, it is not necessary to cover the entire upper part of the fence with the sensor, so that the problem of the sensor shape as in the first conventional technique can be solved. In addition, there is no sanitary problem, and there is an effect that it is possible to detect wherever the handrail of the fence is used to get up.

  Further, according to the technology of the present embodiment, it is possible to detect the timing of raising the upper body by grasping the fence, which is an operation at an earlier stage than the timing of overcoming the fence or the upper body rising from the bed. This eliminates the problem that the nurse is not in time for the second technology, and can effectively prevent a fall accident from the bed.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

It is a system configuration figure concerning an embodiment of the invention. It is a figure which shows the example of the arrangement position of a sensor. It is sectional drawing of the horizontal direction of a support | pillar in the state which attached the sensor to the support | pillar. It is a figure for demonstrating the determination method of rising. It is a functional block diagram of a determination apparatus. FIG. 3 is a diagram showing the contents of a recording unit 21. It is a flowchart of the process of the determination part in the case of performing rising detection using two distortion sensors facing each other. It is a flowchart of the process of the determination part in the case of making a rising determination using four pressure sensors. It is a flowchart of the process which determines with rising when force is larger than a threshold value for predetermined time. It is a flowchart of a process in the case of performing determination using time series sensor data.

Explanation of symbols

5 Bed 7 Judgment Device 9 External Devices 11-14 Pressure Sensors 15, 16 Strain Sensor 21 Recording Unit 23 Sensor Signal Acquisition Unit 25 Judgment Unit 27 Processing Execution Unit

Claims (10)

A bed with a fence,
A sensor arranged to detect at least a force pulling the fence toward the bed;
Obtaining means for obtaining the force data based on a signal output from the sensor;
Recording means for storing reference data used to determine the rising of the user of the bed;
A bed comprising: determination means for comparing the data acquired by the acquisition means with the reference data to determine whether or not the user gets up.   The bed according to claim 1, wherein the sensor is a strain sensor attached to the bed side and the back side of the fence.   The bed according to claim 1, wherein the sensor includes a pressure sensor disposed on a side of the bed at a joint portion between the fence and the bed.   The sensors are a plurality of sensors attached to a plurality of surfaces of the fence column, and the determination means obtains the magnitude and direction of the force as the reference data and signals from the plurality of sensors. The bed according to claim 1, wherein it is determined whether or not the person gets up by comparing the magnitude of the applied force and its direction.   The bed according to claim 1, further comprising a processing execution unit that performs processing according to a determination result by the determination unit. A rising detection device for detecting a rising motion of a user of a bed with a fence,
An acquisition means for acquiring data of the force based on a signal output from a sensor arranged to detect at least a force of pulling the fence toward the bed;
Recording means for storing reference data used to determine rising,
A rising detection apparatus, comprising: a determination unit that compares the data acquired by the acquisition unit with the reference data to determine whether or not the user has risen.   The sensors are a plurality of sensors attached to a plurality of surfaces of the fence column, and the determination means obtains the magnitude and direction of the force as the reference data and signals from the plurality of sensors. The rising detection device according to claim 6, wherein it is determined whether or not it is rising by comparing the magnitude of the applied force and its direction.   The rising detection device according to claim 6, further comprising a process execution unit that performs a process according to a determination result by the determination unit. A program for causing a computer to realize the function of a rising detection device for detecting a rising operation of a user of a bed provided with a fence, the computer comprising:
An acquisition means for acquiring data of the force based on a signal output from a sensor arranged to detect at least a force of pulling the fence toward the bed;
Recording means for storing reference data used to determine rising in a storage device;
A determination unit that compares the data acquired by the acquisition unit with the reference data to determine whether or not the user gets up;
Program to function as.   The sensors are a plurality of sensors attached to a plurality of surfaces of the fence column, and the determination means obtains the magnitude and direction of the force as the reference data and signals from the plurality of sensors. The program according to claim 9, wherein it is determined whether or not it is awake by comparing the magnitude of the applied force and its direction.

Images