JP2010210367A - Sitting-state analyzer and sitting-state analysis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sitting-state analyzer and a sitting-state analysis method capable of analyzing a sitting-state accurately, even if a sitting azimuth is tilted with respect to the front-to-back direction, when analyzing the sitting-state by using a sitting azimuth line. <P>SOLUTION: A temporary sitting azimuth line for dividing a distribution of a pressing force into two is determined, based on a contour in the rear of the buttock (step SA3). Then, the distribution of the pressing force is divided into a plurality of belt-like regions so that the longitudinal direction orthogonally intersects the temporary sitting azimuth line (step SA4), and the sitting azimuth line is determined from each center of gravity position of the distribution of the pressing force in each belt-like region (step SA6). Accordingly, even if the sitting azimuth is tilted with respect to the front-to-back direction, or the like, the sitting azimuth line can be determined accurately. As a result, analysis of the sitting-state based on the sitting azimuth line can be performed accurately. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sitting state analyzing apparatus and a sitting state analyzing method capable of analyzing a sitting state of a seated person.

  2. Description of the Related Art Conventionally, a technique for providing a sensor for detecting pressure on a seat surface of a chair, detecting a pressing force of a seated person, and analyzing the state of the seated person is known. For example, in Patent Document 1, a plurality of nodes are arranged on a seating surface of a chair in order to detect a partial pressing force defined by left and right rows and front and rear columns. Based on the detection results of the plurality of cells, the concentrated position of the pressing force and the uneven distribution of the pressing force are determined. Patent Document 2 discloses a technique for determining a seat bone interval of a seated person using outputs from a plurality of pressure sensor elements provided on a seat.

  In patent document 1 and patent document 2, in order to analyze a seated person's state, the left-right symmetry of a pressing force is investigated. For example, in Patent Document 1, the degree of bias between the total value of the left half partial pressing force and the total value of the right half partial pressing force with respect to the center in the left-right direction is obtained. In Patent Literature 2, the virtual center line L parallel to the front-rear direction is sequentially moved in the left-right direction, whereby the position of the virtual center line L where the pressing force is the most symmetrical on the left and right of the virtual center line L is obtained.

JP 2004-257913 A JP 2002-5761 A

  In the technique described in Patent Document 1, the center in the left-right direction is used as a boundary. Therefore, when the seated person is seated at a position shifted from the center to the left and right, even if the seat is seated so that the pressing force is symmetrical, the pressing force is regarded as being biased with respect to the center of the chair. On the other hand, in the technique described in Patent Document 2, the virtual center line L is sequentially moved in the left-right direction. Therefore, even when the seated person is seated at a position deviated from the center to the left and right, if the seat is seated so that the pressing force is symmetrical, the virtual center where the pressing force is symmetrical on the left and right of the virtual center line L The position of line L is determined. However, since the virtual center line L is set parallel to the front-rear direction, if the direction in which the seated occupant faces (hereinafter referred to as the seating orientation) is oblique to the front-rear direction, the pressing force is temporarily Even if seated so as to be symmetrical, the pressing force is not symmetrical on the left and right of the virtual center line L. That is, in Patent Document 1 and Patent Document 2, it is assumed that a line that bisects the distribution of the pressing force along the seating direction (hereinafter referred to as a seating direction line) is parallel to the front-rear direction. When a person sits obliquely with respect to the front-rear direction, the seating direction line cannot be obtained accurately. As a result, the seated person's condition may not be accurately analyzed.

  The present invention provides a seating state analysis apparatus and a seating state capable of accurately analyzing a seating state even when the seating direction is oblique with respect to the front-rear direction when performing a seating state analysis using a seating direction line. An object is to provide an analysis method.

  In order to achieve this object, the invention according to claim 1 is provided on a seating surface that comes into contact with a seated person at the time of sitting, and a pressing force distribution detector that detects a distribution of pressing force received by the seating surface, Based on the distribution of the pressing force, the buttock rear contour determining unit that determines the buttock rear contour line of the seated person, and the provisional sitting direction line that bisects the distribution of the pressing force based on the buttock rear contour line A temporary seating azimuth line determination unit, a dividing unit that divides the distribution of the pressing force into a plurality of belt-like regions whose longitudinal directions are perpendicular to the temporary seating bearing line, and a single belt-like region. A center of gravity position determining unit that determines a center of gravity position of the distribution, a seating direction line determining unit that determines a seating direction line by performing a predetermined process based on the center of gravity position, and a seating state based on the seating direction line A seating state analysis unit for analyzing And features.

  Here, the sitting state means not only the posture when sitting, but also the state of the seated person (gender, height, weight, etc.). The seating surface means not only the surface of the seating surface but also the inside of the seating surface. In other words, the pressing force distribution detection unit may be provided on the surface of the seating surface and directly contact the seated person, or may be embedded inside the seating surface to contact the seated person via the surface of the seating surface. Also good. In short, the pressing force distribution detector may be provided on the seating surface so that the distribution of the pressing force received by the seating surface can be detected.

  The invention according to claim 2 is the invention according to claim 1, wherein the buttocks rear contour determining unit determines the buttocks rear contour by performing a predetermined line symmetric process, and the temporary seating orientation The line determining unit determines a symmetric line of the buttock rear contour line as the temporary sitting direction line.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a centroid deviation amount determining unit that determines a deviation amount of the centroid position with respect to the seating azimuth line, and the seating azimuth line and the centroid position A seating azimuth line storage unit that stores the amount of deviation in association with each other; a temporary seating azimuth line candidate creation unit that creates a temporary seating azimuth line candidate by moving the temporary seating azimuth line by a predetermined angle; Further comprising a best seating direction line selection unit that selects the seating direction line with the least amount of deviation from the seating direction line storage unit, and the dividing unit further includes the distribution of the pressing force in the longitudinal direction. It divides | segments into the several strip | belt-shaped area | region orthogonal to a temporary seating direction line candidate.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the pressing force distribution detection unit is configured by a pressure sensor having a plurality of pressure sensitive units arranged in a matrix. It is characterized by that.

  According to a fifth aspect of the present invention, there is provided a pressing force distribution detecting step for detecting a distribution of a pressing force received by a seating surface that contacts the seated person at the time of sitting, and a seat occupant's buttocks rear contour line based on the pressing force distribution. A buttock rear contour line determining step, a temporary seating azimuth line determining step for determining a temporary seating azimuth line that bisects the distribution of the pressing force based on the buttock rear contour line, and a distribution of the pressing force. A dividing step of dividing into a plurality of band-like regions so that the longitudinal direction is perpendicular to the temporary seating azimuth line, and a center-of-gravity position determining step of determining the center of gravity position of the distribution of the pressing force with respect to one band-like region And a seating azimuth line determining step for determining a seating azimuth line by performing a predetermined process based on the position of the center of gravity, and a seating state analyzing step for analyzing a seating state based on the seating azimuth line. It is characterized by that.

  The invention according to claim 6 is the invention according to claim 5, wherein the buttocks rear contour determining step determines the buttocks rear contour by performing a predetermined line-symmetric process, and the temporary seating orientation The line determining step is characterized in that a symmetric line of the buttock rear outline is determined as the temporary seating azimuth line.

  The invention according to claim 7 is the invention according to claim 5 or 6, wherein a center-of-gravity deviation amount determining step for determining a deviation amount of the center-of-gravity position with respect to the seating direction line; A seating azimuth line storing step for storing the amount of deviation in association with each other, a temporary seating azimuth line candidate creating step for creating a temporary seating azimuth line candidate by moving the temporary seating azimuth line by a predetermined angle, and the barycentric position Further comprising a best seating direction line selection step for selecting the seating direction line with the smallest deviation amount from the storage result of the seating direction line storage step, and the dividing step further includes the distribution of the pressing force in the longitudinal direction. The direction is divided into a plurality of band-like regions orthogonal to the temporary seating direction line candidates.

  In the first aspect of the present invention, a temporary seating azimuth line that bisects the distribution of the pressing force is determined based on the buttock rear outline. The distribution of the pressing force tends to be substantially symmetrical with respect to the seating direction line. Therefore, by determining a temporary seating direction line that bisects the distribution of the pressing force, the seating direction line can be registered to some extent. Then, the distribution of the pressing force is divided into a plurality of band-like regions whose longitudinal direction is orthogonal to the temporary seating azimuth line. When the longitudinal directions of the plurality of belt-shaped regions are orthogonal to the temporary seating azimuth lines, the center of gravity of the distribution of the pressing force in each belt-shaped region tends to be located in the vicinity of the temporary seating azimuth lines. Since the seating azimuth line is determined based on the position of the center of gravity, the seating azimuth line can be accurately determined even when the seating azimuth is inclined with respect to the front-rear direction. As a result, it becomes possible to accurately analyze the seating state based on the seating azimuth line.

  According to the second aspect of the present invention, the buttock rear contour line is determined by performing a predetermined line symmetric process, and the symmetric line of the buttock rear contour line is determined as a temporary seating azimuth line. The shape of the seated person's buttocks rear contour line is less dependent on the seating state than the distribution of the pressing force that strongly depends on the seating state such as how to apply the weight of the seated person. Therefore, by performing predetermined line-symmetric processing, the shape of the seated person's buttocks rear contour line can be determined without depending on the sitting state as compared with the case of the pressing force. Further, the shape of the buttock rear contour line is substantially bilaterally symmetric with respect to the seating direction line. Therefore, the temporary seating azimuth line can be accurately determined by determining the shape of the buttock rear contour line.

  In the invention according to claim 3, the seating direction line is stored in the seating direction line storage unit in association with the deviation amount of the center of gravity position. And a temporary seating direction line candidate is created by moving a seating direction line by a predetermined angle. And the seating direction line is determined not only from the temporary seating direction line but also from the temporary seating direction line candidates by the processing performed by the center-of-gravity position determination unit and the seating direction line determination unit. The seating direction line determined from the temporary seating direction line candidates is also stored in the seating direction line storage unit in association with the deviation amount of the center of gravity position. Then, the seating azimuth line with the smallest deviation amount of the center of gravity position is selected from the seating azimuth line storage unit by the best seating azimuth line selection unit, so that the seating azimuth line can be determined more accurately.

  In the invention described in claim 4, a pressure sensor having a plurality of pressure sensitive parts arranged in a matrix is used. Since the detection result of the pressing force distribution detector becomes matrix-like data, it is possible to analyze the sitting state using a technique used in the field of image processing. Therefore, analysis of the sitting state is facilitated.

  In the fifth aspect of the present invention, a temporary seating azimuth line that bisects the distribution of the pressing force is determined based on the buttock rear outline. By determining a temporary seating azimuth line that bisects the distribution of the pressing force, the seating azimuth line can be registered to some extent. Then, the distribution of the pressing force is divided into a plurality of band-like regions whose longitudinal direction is orthogonal to the temporary seating azimuth line. When the longitudinal directions of the plurality of belt-shaped regions are orthogonal to the temporary seating azimuth lines, the center of gravity of the distribution of the pressing force in each belt-shaped region tends to be located in the vicinity of the temporary seating azimuth lines. Since the seating azimuth line is determined based on the position of the center of gravity, the seating azimuth line can be accurately determined even when the seating azimuth is inclined with respect to the front-rear direction. As a result, it becomes possible to accurately analyze the seating state based on the seating azimuth line.

  According to the sixth aspect of the present invention, the buttock rear contour line is determined by performing a predetermined line-symmetric process, and the symmetric line of the buttock rear contour line is determined as a temporary seating azimuth line. As described above, the shape of the buttock rear contour line is less dependent on the seating state than the pressing force, and tends to be a shape that is generally symmetrical with respect to the seating direction line. Therefore, the provisional seating direction line can be accurately determined by determining the shape of the buttock rear contour line.

  In the seventh aspect of the invention, the seating direction line is stored in the seating direction line storage unit in association with the deviation amount of the center of gravity position. And a temporary seating direction line candidate is created by moving a seating direction line by a predetermined angle. By the processing performed by the dividing unit, the center-of-gravity position determining unit, and the sitting azimuth line determining unit, the sitting azimuth line is determined not only from the temporary sitting azimuth line but also from the temporary sitting azimuth line candidates. The seating direction line determined from the temporary seating direction line candidates is also stored in the seating direction line storage unit in association with the deviation amount of the center of gravity position. Then, the seating azimuth line with the smallest deviation amount of the center of gravity position is selected from the seating azimuth line storage unit by the best seating azimuth line selection unit, so that the seating azimuth line can be determined more accurately.

1 is a schematic diagram of a seating state analysis apparatus 1 according to an embodiment of the present invention. FIG. 2 is a block diagram showing a control circuit configuration of the seating state analyzer 1. The figure which shows an example of a seat surface pressure data and back surface pressure data. The flowchart explaining the main process in embodiment of this invention. The flowchart explaining the process which concerns on the seating direction line determination process in embodiment of this invention. The figure explaining the outline | summary of the process performed with respect to seating surface pressure data in a seating azimuth | direction determination process. The flowchart explaining the process which concerns on the seating state analysis process in embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Overview Description of the Present Invention>
FIG. 1 is a schematic diagram of a seating state analyzing apparatus 1 and a chair 2 in which the sitting state analyzing apparatus 1 according to an embodiment of the present invention is installed. The seating state analysis device 1 displays a pressure sensor 20 disposed on the surface of the chair 2, a control unit 30 that executes a series of processes related to the seating state analysis, a result of the seating state analysis by the control unit 30, and the like. Display unit 40. The chair 2 includes a seating portion 3 that a seated person's buttocks contact when seated on the chair 2, a chair support leg 4 that supports the seating portion 3, and a backrest portion that contacts the seated person's back when seated on the chair 2. And 5. The pressure sensor 20 includes a seating surface pressure sensor 21 and a back surface pressure sensor 22. The seating surface pressure sensor 21 is provided on the surface of the seating unit 3 in order to detect the pressing force received by the seating unit 3. The back pressure sensor 22 is provided on the surface of the backrest portion 5 in order to detect the pressing force received by the backrest portion 5. Here, the seating surface pressure sensor 21 may be embedded in the seat portion 3. The same applies to the back pressure sensor 22. In addition, even if the pressure sensor 20 has selectively either the seat surface pressure sensor 21 provided in the seating part 3 or the back surface pressure sensor 22 provided in the backrest part 5, it is intended by the present invention. By the way. In short, it is only necessary that the pressure sensor 20 be provided somewhere on the seating surface (including the seating portion 3 and the backrest portion 5) that the seated person contacts when seated on the chair 2. Moreover, in FIG. 1, although the pressure sensor 20, the control part 30, and the display part 40 which are the components of the seating state analysis apparatus 1 are described separately, these may be comprised integrally. Furthermore, the seating state analysis device 1 may be built in the chair 2 and may be integrally configured as a chair system capable of analyzing the seating state.

<Explanation of Block Diagram of the Present Invention>
FIG. 2 is a block diagram illustrating an electrical configuration of the seating state analysis apparatus 1 according to the embodiment of the present invention. The seating state analysis device 1 includes the pressure sensor 20, the control unit 30, and the display unit 40 as described above. The control unit 30 includes a CPU 31, a ROM 32, a RAM 33, an interface 34, and an image forming circuit 35.

  The CPU 31 transmits and receives signals between the ROM 32, the RAM 33, the interface 34, and the image forming circuit 35, and performs various calculations and processes. The ROM 32 stores various programs and parameters for controlling the sitting state analysis apparatus 1. The RAM 33 temporarily stores a program processed by the CPU 31 and data processed by the CPU 31 in its address space.

  The interface 34 receives a control signal from the CPU 31 and transmits the control signal to the pressure sensor 20. The interface 34 receives a pressure signal from the pressure sensor 20 and transmits the pressure signal to the CPU 31.

  The image forming circuit 35 forms an image signal corresponding to the control signal transmitted from the CPU 31 and transmits the image signal to the display unit 40. The image forming circuit 35 has a VRAM (not shown) as a temporary storage area for image display.

  The pressure sensor 20 detects a pressing force applied to the pressure sensor 20 and generates a pressure signal. Specifically, the seat pressure sensor 21 generates a seat pressure signal, and the back pressure sensor 22 generates a back pressure signal. The generated seating surface pressure signal and back surface pressure signal are transmitted to the CPU 31 via the interface 34 and then temporarily stored in the RAM 33 as seating surface pressure data and back surface pressure data. The pressure sensor 20 has a plurality of pressure sensitive units arranged in a matrix. The pressure sensor 20 can be configured by various methods such as a pressure sensitive resistance method, a capacitance method, and an electromagnetic induction method. In this embodiment, as an example, a pressure distribution sheet such as LLSENSOR (registered trademark) manufactured by Shiroku Corporation using an electromagnetic induction method is used. The pressure sensor 20 described above is an example of a pressing force distribution detection unit of the present invention.

FIG. 3A is a diagram for explaining the seating surface pressure data temporarily stored in the RAM 33, and FIG. 3B is a diagram for explaining the back pressure data temporarily stored in the RAM 33. The seating surface pressure sensor 21 provided in the seating unit 3 is configured by m rows × n columns of pressure sensing units. That is, the seating surface pressure data can be handled as image data having m rows × n columns of pixels like the seating surface pressure data shown in FIG. Here, in FIG. 3A, the horizontal direction corresponds to the x direction and the vertical direction corresponds to the y direction. Therefore, as shown in FIG. 3A, the seating surface pressure data has coordinates (x ₀ , y ₀ ) in the lower left and coordinates (x _n−1 , y _m−1 ) in the upper right. At this time, the seating surface pressure sensor 21 is arranged with the upper side in the y direction closer to the backrest 5 side so that the collar portion is on the upper side in the y direction in the seated state. Also, the back pressure data can be handled as image data in the same manner as the seat pressure data.

  The display unit 40 displays an image according to the image signal from the image forming circuit 35. The display unit 40 includes a CRT monitor, a liquid crystal monitor, and the like.

<Description of the flow of the present invention>
FIG. 4 is a flowchart for explaining main processing performed by the CPU 31. In step S <b> 1, the CPU 31 transmits a control signal for causing the pressure sensor 20 to generate a seating surface pressure signal and a back surface pressure signal to the pressure sensor 20 via the interface 34. The pressure sensor 20 transmits the generated seating surface pressure signal and back surface pressure signal to the CPU 31 via the interface 34. The CPU 31 temporarily stores the seat surface pressure signal and the back surface pressure signal from the pressure sensor 20 in the RAM 33 as the seat surface pressure data and the back surface pressure data. Thereafter, the CPU 31 shifts the processing to step S2. The above-described step S1 is an example of the pressing force detection step in the present invention.

  In step S <b> 2, the CPU 31 performs a seating direction line determination process in order to determine a seating direction line of the seating surface pressure data. FIG. 5 is a flowchart for explaining the sitting bearing line determination process performed by the CPU 31. FIG. 6 is a diagram for explaining an outline of processing performed on the seating surface pressure data. Hereinafter, the seating direction determination process will be described in detail with reference to FIGS. 5 and 6.

  In step SA1, the CPU 31 determines a region (pressed region) where a pressing force is generated by sitting in the seating surface pressure data. Since the pressing force generated by the seating changes continuously, the CPU 31 regards an area where the pressing force is a predetermined value or more as a pressed area. This predetermined value may be a threshold value determined in advance through experiments or the like, or may be obtained each time. When obtained each time, as an example, the mode value in the histogram of the pressing force is defined as the pressing force that becomes the background, that is, the pressing force outside the pressed region. Assuming that the background pressing force follows a normal distribution, an area having a pressing force equal to or greater than a value obtained by adding “3σ”, which is three times the dispersion σ, to the background pressing force is reduced by sitting. It may be regarded as a generated area, that is, a pressed area. The area surrounded by the curves BD1, BD2, and BD3 in FIG. 6A indicates an area determined as a pressed area by the process in step SA1. After the pressed area is determined, the CPU 31 proceeds to step SA2.

  In step SA2, the CPU 31 determines a buttock rear outline by performing predetermined line-symmetric processing based on the pressed area determined in step SA1. Specifically, assuming that the contour of the buttock region is a collection of coordinates according to a line-symmetric function, the CPU 31 fits the contour of the pressed region located on the uppermost y-axis to the line-symmetric function (fitting is performed). To determine the buttock rear outline. As this line symmetric function, for example, an even function such as a parabolic function, a hyperbolic function, a cosine function, or a function represented by a linear combination thereof is used. Desirably, a function represented by a linear combination of a plurality of even functions is used, and fitting using the least square method may be performed using a coefficient when the plurality of even functions are linearly combined as a variable. The shape of the back contour of the seated person's buttocks is less dependent on the seating state than the pressing force distribution compared to the distribution of the pressing force that strongly depends on the seating state such as how to put on the weight of the seated person. Therefore, by performing the fitting with a line-symmetric function, the shape of the back contour of the seated person's buttocks is determined without much depending on the seating state as compared with the fitting with respect to the distribution of the pressing force. A curve CTR shown in FIG. 6B is a buttock rear outline determined by the process in step SA2. Thereafter, the CPU 31 shifts the processing to step SA3. In addition, the process performed by step SA2 is an example of the buttock rear outline determination part and the buttock rear outline determination process in this invention.

  The determination of the buttock rear outline means that the position of the buttock of the seated person is determined. The shape of the buttock rear contour line is substantially line symmetric with respect to the seating direction line. Therefore, in step SA3, the CPU 31 determines a symmetric line of the buttock rear contour line based on the buttock rear contour line determined in step SA2. Specifically, the symmetric line of the above-described line symmetric function is the symmetric line of the buttock rear outline. The CPU 31 temporarily stores this symmetry line in the RAM 33 as a temporary seating direction line that bisects the distribution of the pressing force. By determining the provisional seating direction line, the seating direction line can be registered to some extent. The straight line TSD shown in FIG. 6C is a temporary seating direction line TSD determined by the process in step SA3. Thereafter, the CPU 31 shifts the processing to step SA4. In addition, the process performed by step SA3 is an example of the temporary seating direction line determination part and temporary seating direction line determination process in this invention.

  In step SA4, the CPU 31 divides the seating surface pressure data into a plurality of band-like regions. The plurality of belt-like regions are set such that the longitudinal direction is orthogonal to the above-described temporary seating direction line or temporary seating direction line candidate (see step SA11 described later). Specifically, the CPU 31 calculates the inclination of a temporary seating azimuth line temporarily stored in the RAM 33 or a straight line orthogonal to the temporary seating azimuth line candidate. Then, the CPU 31 arranges eight orthogonal straight lines at equal intervals so that the bearing surface pressure data is divided into nine belt-like regions. Each area delimited by the straight lines arranged at equal intervals is a band-shaped area. A plurality of regions ST shown in FIG. 6D are a plurality of band-like regions determined by the process in step SA4. Thereafter, the CPU 31 shifts the processing to step SA5. The process performed in step SC4 is an example of the dividing unit and the dividing process in the present invention.

In step SA5, the CPU 31 determines the barycentric position of the distribution of the pressing force in each band-like region. Specifically, the same processing as the method for obtaining the gravity center of the mass point system is performed on the pressure-sensitive parts included in the individual band-like regions. The process will be described below. The position vector for the pressure sensitive part located at the coordinates (x _i , y _j ) included in the band-like area from the coordinates (x _min , y _min ) of the pressure-sensitive part where the x coordinate and y coordinate in the belt-like area are minimum r _t and the pressing force at the pressure-sensitive portion located at the coordinates (x _i , y _j ) are respectively expressed as p _t . The center-of-gravity position R _c of the belt-like region is determined by using the pressure-sensitive portion included in the belt-like region.

Is determined. However, “P” is the sum of the pressing forces of the pressure-sensitive part included in the belt-like region, that is,

It is. The point indicated by an asterisk in FIG. 6 (e) is the barycentric position in each band-like region ST determined by the process in step SA5. Thereafter, the CPU 31 shifts the processing to step SA6. The process performed in step SA5 is an example of the centroid position determining unit and the centroid position determining step in the present invention.

  In step SA6, the CPU 31 determines a seating azimuth line from the position of the center of gravity of the pressing force distribution determined in step SA5. Specifically, the CPU 31 determines the seating direction line by fitting the barycentric position in the belt-like region using a predetermined function, for example, a linear function. In other words, the slope and intercept of the linear function are determined by the method of least squares using individual centroid positions as samples. This sitting azimuth line is temporarily stored in the RAM 33. Since the longitudinal direction of the belt-like region is orthogonal to the temporary seating azimuth line, the individual gravity center positions tend to be located in the vicinity of the temporary seating azimuth line. Since the seating azimuth line is determined based on the position of the center of gravity, the seating azimuth line can be accurately determined even when the seating azimuth is inclined with respect to the front-rear direction. Further, since the seating azimuth line is determined based on the position of the center of gravity, the distribution of the pressing force is substantially symmetric with respect to the seating azimuth line. A straight line SD shown in FIG. 6F is a seating direction line determined by the process in step SA6. Thereafter, the CPU 31 shifts the processing to step SA7. The process performed in step SA6 is an example of a seating direction line determination unit and a seating direction line determination process in the present invention.

  In step SA7, the CPU 31 determines a deviation amount of the center of gravity position in each belt-like region with respect to the seating direction line. Specifically, the CPU 31 obtains the sum of squares of the distances from the center of gravity positions in the respective belt-like regions to the seating azimuth line, and regards the sum of the squares as the deviation amount of the center of gravity position. The deviation amount of the center of gravity position is temporarily stored in the RAM 33 in association with the seating direction line temporarily stored in the RAM 33. Thereafter, the CPU 31 shifts the processing to step SA8.

  In Step SA8, the CPU 31 determines whether or not the deviation amount of the center of gravity position of the sitting azimuth line temporarily stored in the RAM 33 is smaller than the deviation amount (minimum deviation amount) of the center of gravity position of the best sitting azimuth line stored in the RAM 33. Judging. Here, the best seating azimuth line means a seating azimuth line that minimizes the deviation amount of the center of gravity position. If the determination in step SA8 is affirmative (Y), or if the best seating direction line has not yet been stored in the RAM 33 because the processing in step SA6 and step SA7 has been performed for the first time, the CPU 31 proceeds to step SA9. To do. Alternatively, if the determination in step SA8 is negative (N), the CPU 31 proceeds to step SA10.

  In step SA9, the CPU 31 temporarily stores the seating direction line temporarily stored in the RAM 33 in the RAM 33 as a new best seating direction line. That is, the previous best seating direction line temporarily stored in the RAM 33 before step SA9 is updated in step SA9. At this time, the deviation amount of the center of gravity position temporarily stored in the RAM 33 in step SA7 is also temporarily stored in the RAM 33 as the minimum deviation amount in association with the best seating direction line. Thereafter, the CPU 31 shifts the processing to step SA10.

  In the seating azimuth line determination process shown in FIG. 5, the processes of step SA4 to step SA11 are repeatedly executed in order to more accurately determine the best seating azimuth line. Therefore, in step SA10, the CPU 31 determines whether or not the processing in steps SA4 to SA11 has been repeated a predetermined number of times. The predetermined number of repetitions is set such that the processing from step SA4 to step SA11 is performed with respect to a range of ± 30 ° around the temporary sitting direction line determined in step SA3, for example. When determination of step SA10 is affirmation (Y), CPU31 complete | finishes a series of seating direction line determination processes, and transfers a process to step S3 (refer FIG. 4). Alternatively, if the determination in step SA10 is negative (N), the CPU 31 proceeds to step SA11.

  In step SA11, the CPU 31 creates a temporary sitting direction line candidate by moving the temporary sitting direction line by a predetermined angle. The predetermined angle is set to 1 °, for example, but may be changed as appropriate in consideration of the processing speed and the accuracy of the best seating direction line. A straight line TSDC shown in FIG. 6G is a temporary seating direction line candidate determined by the process in step SA11. Thereafter, the CPU 31 shifts the processing to step SA4.

  In step S3, the CPU 31 performs seating state analysis processing using the seating surface pressure data and the back surface pressure data. Hereinafter, the seating state analysis process will be described with reference to FIG.

  FIG. 7 is a flowchart for explaining the seating state analysis process performed by the CPU 31. In the flowchart shown in FIG. 7, as an example of the seating state analysis process based on the seating azimuth line, a process for determining the quality of the seated person's spine direction (steps SB1 to SB6), and the thigh posture of the seated person Processing for determining pass / fail (steps SB7 to SB12) is shown. The seating state analysis process shown in FIG. 7 is an example of the seating state analysis unit and the seating state analysis process in the present invention.

  In Steps SB1 to SB6, the seated person is notified of whether or not the seated person is seated in a state where the back muscles are straight, that is, whether or not the back muscle direction is good. Sitting in a state where the back muscles are bent may place a burden on the waist of the seated person and cause back pain and the like. That is, the seated person can maintain a comfortable and healthy sitting posture by knowing whether or not the spine direction is good.

  In order to determine whether the seated person is in the back muscle direction, the above-described best seating direction line and the back seating direction line described later are required. The best seating azimuth line has already been determined in the above-described seating azimuth line determination process (step S2), and is temporarily stored in the RAM 33. Therefore, if only the back seating azimuth line is determined, the quality of the seated person's back muscles can be determined. Therefore, the CPU 31 performs processing on the back pressure data in step SB1 to step SB3 described later.

  In step SB1, the CPU 31 performs the same processing as that in step SA4 on the back pressure data. However, the back pressure data does not have a characteristic shape such as the back ridge shape in the seat pressure data. Therefore, unlike the seating surface pressure data, the temporary seating direction line is not defined in the backside pressure data. Therefore, the CPU 31 divides the back pressure data into a plurality of band-like regions whose longitudinal direction is parallel to the x direction. Thereafter, the CPU 31 shifts the processing to step SB2.

  In step SB2, the CPU 31 performs the same process as in step SA5 on the back pressure data. That is, the CPU 31 determines the position of the center of gravity of the back surface pressure data in the band-like region. Thereafter, the CPU 31 shifts the processing to step SB3.

  In step SB3, the CPU 31 performs the same processing as in step SA6 on the back pressure data. That is, the CPU 31 determines the back bearing line by fitting the barycentric position of the distribution of the pressing force in each band-like region using a predetermined function, for example, a linear function. Here, the back azimuth line is a symmetric line in which the distribution of the pressing force generated when the seated person sits on the chair 2 is symmetric as in the case of the sitting azimuth line described above. However, since the back bearing line is different from the above-described seating bearing line in the point required for the back pressure data, this name is used to distinguish it from the sitting bearing line. This back bearing line is temporarily stored in the RAM 33. Thereafter, the CPU 31 shifts the processing to step SB4.

  In step SB4, the CPU 31 determines whether or not the inclination of the best seating azimuth line matches the inclination of the back azimuth line. The slope of the best seating orientation line indicates the seating orientation. The inclination of the back bearing line indicates the direction of the back muscle of the seated person. Therefore, when the inclination of the best sitting azimuth line and the inclination of the back azimuth line coincide with each other, the posture of the seated person's back muscles and the seating direction are aligned, and thus it is considered that the posture is light on the body. On the other hand, when the inclination of the best sitting azimuth line and the inclination of the back azimuth line do not match, the seated person's back muscles and the seating direction are misaligned, which is considered to be a posture with a heavy burden on the body. When determination of step SB4 is affirmative (Y), CPU31 transfers a process to step SB5. Or when judgment of step SB4 is negative (N), CPU31 transfers a process to step SB6.

  In step SB5, the CPU 31 transmits a control signal to the image forming circuit 35 in order to notify the seated person that the direction of the back muscles is in a state where the load on the body is small. The image forming circuit 35 forms an image signal corresponding to the control signal from the CPU 31 and transmits the image signal to the display unit 40. Then, the display unit 40 displays the “back muscle direction OK” according to the image signal from the image forming circuit 35. Thereafter, the CPU 31 shifts the processing to step SB7.

  In step SB6, the CPU 31 transmits a control signal to the image forming circuit 35 in order to notify the seated person that the direction of the back muscles is in a state where the load on the body is heavy. The image forming circuit 35 forms an image signal corresponding to the control signal from the CPU 31 and transmits the image signal to the display unit 40. Then, the display unit 40 displays the “back muscle direction NG” according to the image signal from the image forming circuit 35. Thereafter, the CPU 31 shifts the processing to step SB7.

  In step SB7 to step SB12, whether the thigh posture is good or not, that is, whether the position of the thigh is symmetrical or not and whether the load is evenly applied to the left and right thighs Informed. Sitting when the thigh position is not symmetrical or when the left and right thighs are unevenly loaded can compress the veins on the back of the thigh and cause swelling of the legs. There is. That is, the seated person can maintain a comfortable and healthy sitting posture by knowing the quality of the thigh posture.

In step SB7, the CPU 31 performs the same treatment as in step SA1.
That is, the CPU 31 determines the pressed area in the seating surface pressure data. Thereafter, the CPU 31 shifts the processing to SB8.

  In step SB8, CPU31 determines the area | region (thigh area | region) currently pressed by the seated person's thigh from a to-be-pressed area | region. Specifically, the CPU 31 (1) is located on the lower side of the seating surface pressure data in the y direction. (2) When the shape of the region is fitted with an elliptic function, the major axis of the ellipse is along the y direction. Based on the above condition, the thigh region is determined. Thereafter, the CPU 31 shifts the processing to step SB9.

  In step SB9, the CPU 31 determines whether or not there is a pair of thigh regions at positions symmetrical to the best seating center line. This determination is based on the fact that the thigh tends to be symmetrical with respect to the seating azimuth line when seated in such a manner that the load is equally applied to the left and right. When determination of step SB9 is affirmative (Y), CPU31 transfers a process to step SB10. Alternatively, if the determination in step SB9 is negative (N), the CPU 31 proceeds to step SB12.

  In step SB10, the CPU 31 determines whether or not the distribution of the pressing force in the pair of thigh regions symmetrical with respect to the best seating center line is substantially the same distribution. This determination is based on the fact that the load on the thigh becomes equal to the left and right when seated in such a way that the load is equally applied to the left and right. When determination of step SB10 is affirmative (Y), CPU31 transfers a process to step SB11. Alternatively, if the determination in step SB10 is negative (N), the CPU 31 proceeds to step SB12.

  In step SB11, the CPU 31 indicates that the thigh posture at the time of sitting is good (the position of the thigh region is symmetrical with respect to the best seating center line and the load on the thigh region is equal on the left and right). In order to notify the person, a control signal is transmitted to the image forming circuit 35. The image forming circuit 35 forms an image signal corresponding to the control signal from the CPU 31 and transmits the image signal to the display unit 40. Then, the display unit 40 displays “thigh posture OK” in accordance with the image signal from the image forming circuit 35. Thereafter, the CPU 31 ends the main process after returning the process to the main process.

  In step SB12, the CPU 31 indicates that the thigh posture at the time of sitting is not good (the position of the thigh region is asymmetrical with respect to the best seating center line or the load on the thigh region is different on the left and right). In order to notify the user, a control signal is transmitted to the image forming circuit 35. The image forming circuit 35 forms an image signal corresponding to the control signal from the CPU 31 and transmits the image signal to the display unit 40. Then, the display unit 40 displays “thigh posture NG” in accordance with the image signal from the image forming circuit 35. Thereafter, the CPU 31 ends the main process after returning the process to the main process.

<Modification>
The present invention is not limited to the embodiments described so far, and various modifications and changes can be made without departing from the spirit of the present invention. An example of the modification will be described below.

  In the seating state analysis process shown in FIG. 7, a process corresponding to steps SA7 to SA11 of the seating direction determination process (FIG. 5) may be performed on the back pressure data. In other words, the temporary back bearing line candidate is determined by moving the back bearing line by a predetermined angle, the deviation amount of the center of gravity position is obtained with respect to the temporary back bearing line candidate, and the temporary back bearing having the smallest deviation amount of the center of gravity position A line candidate may be determined as the best back bearing line. By performing this process, the back bearing line can be determined more accurately.

  In the above-described embodiment, as an example of the seating state analysis process, a process for determining the quality of the seated person's back muscles (steps SB1 to SB6) and a process for determining the quality of the seated person's thigh posture (step SB7). To Step SB11). Since the present invention is characterized in that the seating azimuth line can be accurately obtained, the content of the seating state analysis process is not limited to the above-described embodiment. For example, as in the technique described in Patent Document 2, analysis for determining the ischial interval may be performed as the seating state analysis process.

  In the above-described embodiment, the analysis result of the sitting state is displayed on the display unit 40 (see FIG. 7). However, the display unit 40 is an example of a configuration for notifying the seated person of the analysis result of the seating state, and may report the analysis result of the seating state by voice or the like, for example. Furthermore, since the present invention is characterized in that the seating direction line can be accurately obtained, the configuration for notifying the seated person of the analysis result of the seating state is merely an example of a method of using the analysis result of the seating state. And not required. Therefore, for example, the chair is deformed so as to correct the posture of the seated person using the analysis result, and it is used for controlling the airbag as in the technique described in Patent Document 2. Even if it is used, it is intended by the present invention.

DESCRIPTION OF SYMBOLS 1 Seating state analysis apparatus 2 Chair 3 Seating part 4 Chair support leg 5 Backrest part 20 Pressure sensor 21 Seat surface pressure sensor 22 Back surface pressure sensor 30 Control part 31 CPU
32 ROM
33 RAM
34 Interface 35 Image forming circuit 40 Display unit

Claims (7)

A pressing force distribution detection unit that is provided on a seating surface that comes into contact with a seated person at the time of sitting and detects a distribution of pressing force received by the seating surface;
Based on the distribution of the pressing force, a buttock rear outline determining unit that determines a buttock rear outline of the seated person,
A temporary sitting azimuth line determining unit that determines a temporary sitting azimuth line that bisects the distribution of the pressing force based on the buttock rear contour line;
A dividing unit that divides the distribution of the pressing force into a plurality of belt-like regions whose longitudinal direction is orthogonal to the temporary seating orientation line;
A center-of-gravity position determination unit that determines the center-of-gravity position of the distribution of the pressing force with respect to one of the band-shaped regions;
A seating direction line determination unit that determines a seating direction line by performing predetermined processing based on the position of the center of gravity;
Based on the seating azimuth line, a seating state analysis unit that analyzes the seating state,
A seating state analyzing apparatus comprising: The buttock rear outline determining unit determines the buttock rear outline by performing a predetermined line symmetric process,
The temporary sitting azimuth line determining unit determines a symmetric line of the buttock rear contour line as the temporary sitting azimuth line;
The seating state analyzing apparatus according to claim 1. A center-of-gravity deviation determination unit that determines an amount of deviation of the center-of-gravity position with respect to the seating orientation line;
A seating direction line storage unit that stores the seating direction line and the deviation amount of the gravity center position in association with each other;
A temporary sitting direction line candidate creating unit that creates a temporary sitting direction line candidate by moving the temporary sitting direction line by a predetermined angle;
A best seating azimuth line selection unit that selects the seating azimuth line with the least amount of deviation of the center of gravity position from the seating azimuth line storage unit;
The dividing unit further divides the distribution of the pressing force into a plurality of band-like regions whose longitudinal direction is orthogonal to the temporary seating direction line candidates.
The seating state analyzing apparatus according to claim 1 or 2, characterized in that The pressing force distribution detector is
It is constituted by a pressure sensor having a plurality of pressure sensitive parts arranged in a matrix.
The sitting state analysis apparatus according to any one of claims 1 to 3, wherein A pressing force distribution detection step for detecting the distribution of the pressing force received by the seating surface that contacts the seated person at the time of sitting;
Based on the distribution of the pressing force, a buttock rear outline determination step for determining a buttock rear outline of the seated person;
Based on the buttock rear contour line, a temporary seating direction determination step for determining a temporary seating direction line that bisects the distribution of the pressing force;
A dividing step of dividing the distribution of the pressing force into a plurality of band-like regions whose longitudinal direction is orthogonal to the temporary seating orientation line;
A center-of-gravity position determining step for determining a center-of-gravity position of the distribution of the pressing force with respect to one of the band-shaped regions;
A seating orientation line determination step for determining a seating orientation line by performing a predetermined process based on the position of the center of gravity;
Based on the seating azimuth line, a seating state analysis step of analyzing the seating state,
A seating state analysis method comprising: The buttock rear outline determination step determines the buttock rear outline by performing a predetermined line symmetric process,
The temporary sitting azimuth line determining step determines a symmetric line of the buttock rear contour line as the temporary sitting azimuth line;
The seating state analysis method according to claim 5. A center-of-gravity deviation determination step of determining a deviation amount of the center-of-gravity position with respect to the seating orientation line;
A seating direction line storing step of storing the seating direction line and the deviation amount of the gravity center position in association with each other;
A temporary sitting direction line candidate creating step of creating a temporary sitting direction line candidate by moving the temporary sitting direction line by a predetermined angle;
A best sitting azimuth line selection step of selecting the seating azimuth line with the least amount of deviation of the center of gravity position from the storage result of the sitting azimuth line storage step;
The dividing step further divides the distribution of the pressing force into a plurality of band-like regions whose longitudinal direction is orthogonal to the temporary seating orientation line candidates.
The seating state analysis method according to claim 5 or 6.