KR20180019805A - Posture estimation method sitting on a chair - Google Patents

Abstract

The present invention provides a seating posture estimating method which estimates a posture by mounting a sensor only on a seat of a chair. The seating posture estimating method of the present invention comprises the following steps of: dividing an area measuring a pressure in the entire area of the seat into at least one section through at least one pressure sensor installed in the seat of the chair, and deriving a result value which calculates a ratio between a load value measuring a load due to seating by each pressure sensor for each section and a weight value of a seated person; and determining whether the seated person leans against a back of the chair if a first reference value which is used as a criterion for determining a back leaning state is greater than or equal to or less than the result value.

Description

[0001] The present invention relates to a sitting posture estimation method,

More particularly, the present invention relates to a sitting posture estimation method capable of estimating and determining seven main sitting positions by comparing chair seats divided into four regions and comparing weight distribution distributed in each of the four regions .

The posture imbalance caused by modern people 's long sitting has led to the development of ergonomic chair technology.

In particular, the development of office workers based on ergonomic researches such as lumbar support and backbone tilting devices have been developed steadily to relieve the lumbar discomfort that most long -

However, other recent studies have shown that the attitude and habit of the user plays an important role in inducing correct posture in addition to the ergonomic function of the chair itself.

Studies have been carried out that the risk of posture is reduced even if it is trained to teach the musculoskeletal system due to wrong attitude and to sit in the right posture.

According to studies on user education effects such as application ergonomics and office ergonomics, the risk of musculoskeletal disorders was relatively low after 16 months of providing ergonomic posture training to the seated, and the adjustable chair and office ergonomics Studies concurrently reported that musculoskeletal-related symptoms decreased after 5 months.

In this way, it is known from various documents that the right posture ratio is increased and the posture discomfort is reduced by just paying attention to the posture of the seated person.

In recent years, technologies have been introduced to enable IT to maintain a right attitude in a more aggressive way by incorporating it into a chair.

The sensor is used to monitor the posture of the seated person in real time and shows the current posture state or a posture correction system that warns when the wrong posture is taken.

In this background, various technical approaches for sensing the posture of the seated person in real time are being made. As a study to observe the posture changes of the seated person from the past, a method of attaching an electrode to a chair or mounting a body pressure measurement mat on a seat was attempted. However, It was not.

However, in recent years, studies have been conducted aiming at commercialization of products having posture management function, and a system capable of posture management during actual work is being developed by integrating a posture measurement system into a chair or a cushion.

On the other hand, a method of using a monitor camera as a method for escaping a system dependent on a chair and a method of wearing an acceleration sensor on the body have been attempted. However, most studies have been performed using a pressure value measured by mounting a pressure sensor on a back plate and a seat And to estimate the posture of the seated person.

In the related art, there is a problem that system cost is increased due to mounting of a sensor on the backboard as well as the seatboard as a limitation point of the pressure sensor-based seating monitoring system.

In addition, since the conventional technology requires not only the cost of the added sensor but also the backing structure for attaching the sensor, it is necessary to increase the cost of the sensor. Also, the signal line connecting the back sensor and the seat sensor is required to be assembled and maintained There is a problem that it becomes a factor that makes management difficult.

Korean Patent Publication No. 2010-0125880 (December 1, 2010) Korean Registered Patent No. 10-1136909 (Apr. 9, 2012)

In order to solve the above-described problem, the seating posture estimation method of the present invention attempts to estimate a posture by attaching a sensor only to a seat of a chair.

In particular, it is possible to estimate and judge the seven main sitting positions including the back rest position.

It is another object of the present invention to determine a specific posture by dividing a chair seat into four regions and comparing the weight distributed to each of the four regions to the weight of the user to determine whether or not the chair seat is dammed with only the seat sensor.

According to another aspect of the present invention, there is provided a seating posture estimation method for dividing an area measuring a pressure in an entire area of a seat through at least one pressure sensor installed on a seat of a chair into at least one zone, Deriving a first result obtained by calculating the ratio of the load value measured by each pressure sensor to the weight of the seated person and the weight value of the seated person as a ratio, and determining whether the first reference value, And determining whether or not the backrest of the seated person is in the backrest state when the seat backrest is in a small or small state.

According to the present invention, the load value is determined by S1, which is the load value measured through the pressure sensor located in the first zone on the front left side of the seat in the total area of the seat, S2 as a load value measured through a pressure sensor located on the left side of the seat, S3 as a load value measured through a pressure sensor located in a third area on the left rear side of the seat in the entire area of the seat, And the load value S4 measured through the pressure sensor located in the fourth zone.

According to the present invention, the first resultant value is calculated through the following equation (1).

[Equation 1]

(Where, W is the weight value of the seated person).

According to the present invention, when the first reference value is greater than or equal to the first result value, it is determined that the back of the back is in a recessed state, and when the first reference value is less than the first result value, .

According to the present invention, the reference value is 0.7 to 0.9.

According to the present invention, it is determined whether or not the seated person is in the back light state. If the second result value derived from the following formula (2) is larger than the second reference value 0.6, If the second result value derived from Equation (2) is smaller than the second reference value 0.4, it is determined that the second result value is derived from Equation (2) 0.6, a state of sitting on the center of the seat is determined.

&Quot; (2) "

According to the present invention, it is determined whether or not the seated person is in a lighted state. If the third result value derived from the following formula (3) is larger than the third reference value 0.64, If the third resultant value derived from Equation (3) is smaller than the third reference value 0.36, it is determined that the third resultant value is sited on the right side of the seat. If the third resultant value derived from Equation (3) 0.36 to 0.64, it is determined that the seat is in a state of sitting right and left in balance.

&Quot; (3) "

According to the present invention, when the first result value derived through Equation (1) below is smaller than the first reference value 0.1, it is determined that the first result value is standing without standing on the chair.

As described above, in the seating posture estimation method of the present invention, the area for measuring the pressure in the entire area of the seat is divided into one or more zones through one or more pressure sensors installed on the seat of the chair, A step of deriving a result of calculating a weight value of a seated person by a load value measured by a zone, a step of calculating a ratio of a weight value of a seated person to a seat of a seated person when the first reference value, And determining whether or not the backrest is in a backlash state.

Accordingly, it is possible to estimate and judge seven major seating positions by dividing the chair seat into four regions and comparing and analyzing the weight distributed among the four regions.

In addition, it is possible to accurately determine the attitude type through only the four pressure sensors installed on the seat, thereby reducing the manufacturing cost by simplifying the measuring sensor for the attitude estimation and the parts for electric and signal ac.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing a state in which a pressure sensor is mounted on a chair for seating posture estimation according to the present invention; FIG.
2 is a plan view of a pressure sensor mounting position for estimating a sitting posture of the present invention.
3 is a view showing a sitting posture estimation type according to the present invention.
FIG. 4 is a view showing the body center position according to each posture type through the present invention. FIG.
FIG. 5 is a distribution diagram showing the body center position of the posture type of each zone of the seat through the present invention. FIG.
FIG. 6 is a distribution chart showing the posture type of a seat by zones according to the present invention. FIG.
FIG. 7 is a distribution chart showing the posture types of the front, rear, left and right sides of the seat according to the present invention. FIG.
8 is a flowchart showing a seating posture estimation method of the present invention.

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

First, it should be noted that, in the drawings, the same components or parts have the same reference numerals as much as possible. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

Fig. 1 is an exploded perspective view showing a state in which a pressure sensor is mounted on a chair for estimating a sitting posture of the present invention, Fig. 2 is a plan view showing a position where a pressure sensor is mounted for estimating a sitting posture of the present invention, FIG. 4 is a graph showing a center-of-gravity position according to each posture type according to the present invention, and FIG. 5 is a graph showing the body center position FIG. 7 is a distribution chart for classifying the posture types of the front, rear, left and right sections of the seat according to the present invention, and FIG. 8 is a distribution chart Fig. 8 is a flowchart showing a seating posture estimation method of the invention.

The present invention is for judging a state in which the backrest is leaning against the backrest of a chair when the seated person is seated on the chair.

That is, the reason for determining the sitting posture can be estimated on the basis of the wrong posture depending on whether or not the backrest is in the backrest of the chair.

As shown in Figs. 1 and 2, four pressure sensors are provided on a seat of a chair, and an area for measuring pressure in the entire area of the seat is divided into four zones.

The four zones are divided into the front left and right sides of the seat and the rear left and right sides of the seat in the entire area of the seat.

The first result value is derived by calculating the weight value of the seated person and the weight value measured by dividing the seat into four zones by a ratio.

That is, the area measuring the pressure in the entire area of the seat is divided into at least one zone through one or more pressure sensors installed on the seat of the chair, and the load caused by seating is measured by the load value measured by each pressure sensor in each zone, Value is calculated as a ratio.

Thereafter, if the first reference value, which serves as a criterion for determining whether or not the backlight is present, is equal to or smaller than the first result value, or if the first reference value is less than or equal to the first result value,

Here, the load value is a load value S1, which is a load value measured through a pressure sensor located in a first zone on the front left side of the seat in the entire area of the seat, A load value measured through the pressure sensor located in the third zone on the left rear side of the seat in the entire area of the seat, S3 being a load value measured through the fourth area on the rear right side of the seat in the entire area of the seat, Is the sum of the load value S4 measured through the pressure sensor located at the center.

The load value obtained as above can be derived from the weight value of the seated person and the first result value calculated through the following equation (1).

(Where, W is the weight value of the seated person).

Next, if the first resultant value is greater than or less than the first reference value, it is determined whether or not the back rest state of the seat back of the seated person is determined.

The first reference value is 0.7 to 0.9, and the load ratio (% BW) is 70 to 90%.

That is, when the first reference value 70 to 90% is equal to or greater than the first result value, it is determined that the back of the user is in a backward state. When the first reference value 70 to 90% is less than the first result value, It is judged to be in a soldering state.

The determination of the backlight dam condition based on the first reference value is the same as the inequality in Table 1 below.

condition
Condition
A. Fill the back
First result value> First reference value (0.7 to 0.9)
B. Having a back
The first reference value (0.1) < the first resultant value < the first reference value (0.7 to 0.9)
C. standing
The first result value < the first reference value (0.1)

The first reference value, which serves as a basis for judging whether or not the lamp was damaged, was derived from the following experimental results.

As shown in FIG. 3, the seating posture to be determined through the present invention is as follows.

1) In the sitting position (Erect)

2) The sitting posture (Middle),

3) The back posture (Front)

4) I look forward to the back, but the hip slips forward slouch,

5) Sided body to the left or right side

5) Sided body tilting to the left or right can be subdivided into Sided-Lefty and Sided-Righty.

In addition, there is a standing posture not sitting on a chair.

The pressure distribution diagram of the seat according to the attitude type as described above shows that the body pressure measured on the seat exhibits not only the distribution shape but also the maximum / average pressure according to the attitude type.

The body pressure measuring state of the seat which is variable through the five sitting positions is a body pressure distribution measuring device composed of 324 cells arranged in a lattice arrangement of 18 cells each in the horizontal and vertical directions to measure the seat pressure distribution for every 10 seconds Respectively.

Through the above experiment, pressure and ratio data for each seat zone can be obtained for each sitting position as shown in Table 2 below.

posture
Total (N)
(% BW)
Weight of Front-Rear half area
(Weight ratio)
Weight of Left-Right half area
(Weight ratio)
Erect
414N
(58%)
130N-283N
(1: 2.2)
201N-213N
(1: 1)
Middle
642N
(90%)
355N-289N
(1.2: 1)
312N-330N
(1: 1.1)
Front
589N
(83%)
554N-36N
(15: 1)
299N-290N
(1: 1)
Slouch
398N
(56%)
236N-163N
(1.4: 1)
202N-196N
(1: 1) Sided
(Righty,
Lefty)
450N
(63%)
211N-240N
(1: 1.1)
348N-177N
(1: 1.9)

As shown in [Table 2], in the Erect and Slouch posture, the load applied to the seat is 58% and 56% of the weight value, respectively, and is greatly reduced.

According to the posture type, the body weight ratio in the first half and the second half was changed. In the erect posture, the body weight was more than twice that of the seat backward at 1: 2.2. In the middle posture, In the front position, there is a considerable load distribution in front of the seat at 15: 1.

In the case of the slouch posture, the specific gravity distributed in the front of the seat was about 40% as 1.4: 1.

In most postures, the load ratio applied to the right and left hemispheres was measured equally, but in the sided posture biased to the left and right, the load distribution was twice as high as the biased one.

Through this experiment, it is possible to judge whether or not the backrest is rested on the chair by deriving the reference value using only the pressure sensor on the seat.

In summary, when% BW of the measured value is less than about 70% in a system equipped with four pressure sensors in the front left, front right, rear left, and rear right in the entire area of the seat, can do.

Through this, it is possible to judge the posture that the hip slides forward (slouch) while leaning on the back, leaning on the sitting posture (Erect) deep inside the seat.

The erect posture and the slouch posture can be distinguished in detail as the weight ratio applied to the front and rear of the seat. If% BW is more than 90%, it can be judged that the backbone is completely removed from the back.

In this way, it is possible to judge the posture to be "Front" by releasing the back of the back and the sitting posture.

The determination of the backlash by the above method can be seen from the result of the body center position and the weight ratio of the six seating positions to be expressed below.

As shown in FIGS. 4 and 5, the experimental method is a method in which the body pressure distribution of the seat is detected by four pressure sensors for 10 seconds for each posture, and the average result value and the body center position Are as follows.

1), the first result of the sitting posture (Erect) was 0.75 ~ 0.81, which is 75 ~ 81% in terms of% BW.

This is because the backrest is rested on the back because it falls within the range of the first reference value 0.7 to 0.9 for judging whether or not the backrest is damaged. However, since the degree of dispersion of the upper body weight in the backrest is small, Lt; / RTI &gt;

2) The first result of the middle position was 0.91 ~ 0.92, which is 91 ~ 92% in terms of% BW.

This is because the first resultant value is larger than the first reference value 0.7 to 0.9 for judging whether or not the lamp is dammed. That is, since the upper body weight is not dispersed in the back, the load value burdened on the seat is increased, so that the first resultant value is slightly higher than the first reference value.

3) The first result of the front posture with the back is 0.92 ~ 0.93, which is 92 ~ 93% in terms of% BW.

This is because the first resultant value is larger than the first reference value 0.7 to 0.9 for judging whether or not the lamp is dammed. That is, the load is located forwardly and centrally over the entire area of the seat, the upper body weight is not dispersed in the back, the load value burdened on the seat is increased, and the first resultant value is measured to be higher than the first reference value.

4) The first result of the slouch with the hip slipping forward was 0.64 ~ 0.66, which is 64 ~ 66% in terms of% BW.

This is because the first resultant value is smaller than the first reference value 0.7 to 0.9 for judging whether the lamp is dammed or not, and thus the lamp is judged to be in a stagnant state. That is, the load is located in front of the entire area of the seat, the body weight is dispersed in the back, the load value burdened on the seat is lowered, and the first resultant value is measured to be lower than the first reference value.

5) The first result of Sided-Lefty was 0.76 ~ 0.81, which is 76 ~ 81% in terms of% BW.

This is because the first resultant value belongs to the range of the first reference value 0.7 to 0.9 for judging whether or not the backlight is dammed, so that the back of the back is leaned, but the degree of dispersion of the upper body weight on the back is small, And has a first result value slightly shifted from the first reference value.

6) The first result of Sided-Righty was 0.77 ~ 0.85, which is 77 ~ 85% in terms of% BW.

This is because the first resultant value belongs to the range of the first reference value 0.7 to 0.9 for judging whether or not the backlight is damaged, so that the back is leaned against the back, but the degree of the upper body weight is less dispersed in the backrest, The load has a first result value which is slightly smaller than the first reference value.

As a result, if the first result value obtained by calculating the load value measured in each zone and the weight value of the seated person as a ratio is compared with the first reference value derived through the experiment, if the first reference value is greater than or equal to the first result value There is a basis for judging that the user has leaned back on the back, and when the first reference value is smaller than the first result value, it is a basis for judging the back condition of the back on the back.

As described above, a method of determining the body center position for each posture type in the area divided into the front and the back of the entire area of the seat after determining the back light dam state is as follows.

First, it is determined whether or not the seated person is in a lighted state. If it is determined that the second result value derived through the following formula (2) is larger than the second reference value 0.6, ] Is less than the second reference value 0.4, it is determined that the second result value is in a state of sitting at the rear of the seat.

If it is determined that the seated person is in a lighted state, the second resultant value derived from Equation (2) is within the second reference value range of 0.4 to 0.6.

The determination of the forward and backward position of the back seat through the second reference value is the same as the inequality in Table 3 below.

condition
Condition
A. Sit back
The second resultant value < second reference value (0.4)
B. Sit in the middle
The second reference value 0.4, the second result value &lt; the second reference value 0.6,
C. Sit in front
Second result value > second reference value (0.6)

After determining whether or not the seated person is in a lighted state, the method of determining the body center position for each type of posture in the area divided into the right and left of the entire area of the seat is as follows.

First, it is determined whether or not the seated person is in a lighted state. If the third result value derived through Equation (3) is larger than the third reference value 0.64, it is determined that the seat is leaning to the left of the seat, 3] is smaller than the second reference value 0.36, it is determined that the third result value is sited on the right side of the seat.

If the third resultant value derived from Equation (3) is within the third reference value range of 0.36 to 0.64 after judging whether or not the seated person is in the lighted state, it is judged that the seat is sitting right and left in balance.

The determination of the right and left positions of the back seat through the third reference value is the same as the inequality in Table 4 below.

condition
Condition
A. Left offset
Third result value> third reference value (0.64)
B. Balance between left and right
Third reference value (0.36)? Third result value? Third reference value (0.64)
C. Right shift
The third result value <the third reference value (0.36)

As shown in FIG. 6, the determination of the center of gravity of the seat in the longitudinal direction of the seat by the posture type is based on the following experimental results.

That is, the result of the second reference value, which is a criterion for determining whether the seat is seated in front of or behind the seat, is verified through the experimental result.

In the above test method, the pressure distribution of the seat was detected by four pressure sensors for 10 seconds for each posture, and the weight ratio was calculated four times.

The x values to be described below are the second and third result values of the front and rear sides of the sheet, y is the third and fourth result values of the left and right sides of the sheet, and z is the first result value.

1) In the sitting position (Erect)

 0 < x < 0.4, 0.36 < y < 0.64, 0.1 &

The erect posture is determined by the inequality of the x value, the weight centimeter is located behind the front and back of the seat, is positioned in a balanced manner in the seat by the inequality of the y value, .

2) The sitting posture (Middle)

0 &lt; x < 0.6, 0.36 < y < 0.64, 0.85 &

The middle posture is a range of states in which the weight center of the seat is uniformly positioned in front of and behind the seat through an inequality of x values, and is positioned in a balanced manner in the seat by the inequality of the y value, .

3) The back posture (Front)

0.6 <x <1, 0.36 <y <0.64, 0.76 <z <1

The front posture is a position in which the weight center is located on the front side of the seat through an inequality of x value, is positioned in a balanced manner in the seat by the inequality of the y value, .

4) I look forward to the back, but the hip slips forward slouch,

0.4 <x <0.1, 0.36 <y <0.64, 0.1 <z <0.76

The slouch posture is based on the inequality of x values, the weight center is located on the front side of the seat, the weight is positioned in a balanced manner on the seat through the inequality of the y value, and the range of the state .

5) Sided-Lefty

0 <x <1, 0.64 <y <1, 0.1 <z <1

In the Sided-Lefty posture, the weight is shifted to the left in the seat through the inequality of the y value.

6) Sided-Righty

 0 < x < 1, 0 < y < 0.34, 0.1 &

It can be seen that the Sided-Righty posture is positioned such that the body weight is biased to the right side in the seat through an inequality of y value.

7) Standing

0 <x <1, 0 <y <1, 0 <z <0.1

It can be seen that the x, y, and z values hardly occur in the standing posture.

As described above, as a result of summarizing the inequality by posture type, the posture estimation according to the condition is as shown in Table 5 below.

Back light condition
Seat left and right state
Before and after seat
posture



A
(Duster)
A (right) A (back)
6. Righty
B (in) C (front)
B (balance) A (back)
Middle B (in) C (front) 3. Front
C (left) A (back)
5. Lefty B (in) C (front)


B
(Light dam)
A (right) A (back)
6. Righty B (in) C (front)
B (balance) A (back) 1. Erect B (in)
4. Slouched C (front)
C (left) A (back)
5. Lefty B (in) C (front)


C
(rising)
A (right) A (back)


0. Standing B (in) C (front)
B (balance) A (back) B (in) C (front)
C (left) A (back) B (in) C (front)

As shown in [Table 5], if the positional state of the left, right, and balance of the seat and the positional state of the front, middle, and rear of the seat are determined step by step after determining whether or not the backrest is damaged, .

In addition, as shown in FIG. 8, the first result value, which is the ratio of the body weight to the body weight, is derived, and then the second resultant value, which is the forward and backward position, and the third resultant value, which is the right and left position, are derived in order.

Here, the order of the first resultant value, the second resultant value, and the third resultant value may be changed.

The resultant values are substituted into the inequality, and if the value is larger or smaller, the corresponding posture type can be determined in the seven posture types.

The above-described seating posture estimation method has an effect that the chair seat can be divided into four regions and the seven main sitting positions can be estimated and determined by comparing and analyzing the weight distributed to each of the four regions.

Specifically, the first result obtained by deriving one reference value, two reference values, and three reference values through the experiment, and then calculating the ratio between the load measurement values of the pressure sensor and the weight value of the occupant by seating on the seat, The resultant value and the third resultant value are calculated as a ratio, and the respective reference values are compared with the respective result values, so that it is possible to estimate and determine the corresponding posture type when the value is larger or smaller.

In addition, it is possible to accurately determine the attitude type through only the four pressure sensors installed on the seat, thereby reducing the manufacturing cost by simplifying the measuring sensor for the attitude estimation and the parts for electric and signal ac.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

Claims (8)

The pressure measuring area of the seat is divided into one or more zones by one or more pressure sensors installed on the seat of the chair, and the load by the pressure sensors measured by each pressure sensor and the weight value of the seated person Deriving a first resultant value calculated as a ratio,
And determining whether or not the backrest is in a back position of the chair's seat when the first reference value, which is a criterion for determining whether or not a backlash condition is a standard, is greater than or equal to the first outcome value.
The method according to claim 1,
The load value,
A load value S1 measured through a pressure sensor located in a first area on the left front side of the seat in the entire area of the seat,
S2, which is the load value measured through the pressure sensor located in the second region on the right side of the front side of the seat in the entire area of the seat,
A load value S3 measured through a pressure sensor located in a third zone on the left rear side of the seat in the entire area of the seat,
And S4, which is a load value measured through a pressure sensor located in a fourth zone on the rear right side of the seat in the entire area of the seat.
3. The method of claim 2,
Wherein the first resultant value is a first value,
Is calculated through the following equation (1). &Lt; EMI ID = 1.0 &gt;
[Equation 1]

(Where, W is the weight value of the seated person).
The method according to claim 1,
If the first reference value is greater than or equal to the first result value,
When the first reference value is smaller than the first reference value, determining that the back is in the back state.

The method according to claim 1,
Wherein the first reference value is 0.7 to 0.9.
3. The method of claim 2,
After determining whether the seated person is in a lighted state,
If it is determined that the second resultant value obtained through the following equation (2) is greater than the second reference value 0.6,
If it is determined that the second result value derived from the following formula (2) is smaller than the second reference value 0.4,
When the second result value derived from the following equation (2) falls within the range of the second reference value of 0.4 to 0.6, it is determined that the user is seated at the center of the seat.
&Quot; (2) &quot;

3. The method of claim 2,
After determining whether the seated person is in a lighted state,
If the third resultant value obtained through the following formula (3) is larger than the third reference value 0.64, it is determined that the third resultant value is sited on the left side of the seat,
If the third resultant value obtained through the following equation (3) is smaller than the third reference value 0.36, it is determined that the third resultant value is located on the right side of the seat,
When the third result value obtained through the following equation (3) falls within the third reference value range of 0.36 to 0.64, it is determined that the seat is in a state of sitting right and left in a balanced manner
&Quot; (3) &quot;

The method of claim 3,
When the first resultant value obtained through the following equation (1) is smaller than the first reference value 0.1, it is determined that the user does not sit on the chair and stands up.

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