Office seat inclination angle adjusting method based on pressure distribution acquisition

Abstract

The invention relates to the technical field of seat inclination angle adjustment, and particularly discloses an office seat inclination angle adjustment method based on pressure distribution acquisition, which comprises the following steps: step S1: by arranging array pressure acquisition points on the surface of a cushion, acquiring pressure data of hip and thigh areas of a user in real time, and constructing a pressure distribution curved surface; s2, calculating the position of the pressure center in real time based on the pressure distribution curved surface, and continuously monitoring whether the position moves towards the chair back or not; if displacement occurs, synchronously acquiring state data such as displacement distance and acceleration; and S3, estimating the average equivalent friction force change of the seat cushion interface according to the state data, further calculating an angle compensation value required for counteracting gliding, and automatically driving a mechanism to adjust the inclination angle of the seat cushion.

Description

Technical Field

[0001] This invention relates to the field of seat tilt adjustment technology, specifically to a method for adjusting the tilt angle of an office chair based on pressure distribution data acquisition. Background Technology

[0002] In the office environment, the comfort of office chairs is closely related to the user's health and work efficiency.

[0003] However, existing office chairs have many problems. When users sit in office chairs, their postures vary, and the angle between their upper and lower body is complex. Sometimes the angle is close to a right angle, while other times it is an obtuse angle. When the angle is obtuse, the user's body is prone to sliding down. This phenomenon is more pronounced in office chairs equipped with cushions. Because cushions have a certain degree of softness, they will sink under the pressure of the user's body, further exacerbating the tendency to slide down.

[0004] This tendency to sag not only affects a user's posture, but prolonged poor posture can also lead to a range of health problems, such as spinal deformities and lower back pain. Furthermore, constantly adjusting posture to maintain stability can distract the user and reduce work efficiency. Therefore, how to automatically adjust the tilt angle of an office chair based on the user's actual posture to prevent sag and improve the chair's comfort and practicality has become a pressing technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for adjusting the tilt angle of an office chair based on pressure distribution data acquisition, thereby solving the following technical problems.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for adjusting the tilt angle of an office chair based on pressure distribution data collection includes the following steps: Step S1: The area of ​​the user's buttocks and thighs that comes into contact with the office chair is recorded as the contact area; a pressure acquisition array is set on the surface of the office chair cushion, which is used to acquire the pressure applied by the user's contact area on the surface of the cushion in real time, and obtain the pressure distribution surface. Step S2: Based on the pressure distribution surface, determine the pressure center of the contact area in real time, and determine whether there is displacement of the pressure center. If there is displacement, obtain state data, which includes displacement distance, displacement acceleration and equivalent pressure value. Step S3: Based on the state data, obtain the average equivalent friction force of the pressure center on the surface of the seat cushion, obtain the compensation force value according to the average equivalent friction force, determine the seat cushion angle compensation value according to the compensation force value, and adjust the seat cushion angle of the office chair according to the seat cushion angle compensation value.

[0007] As a further aspect of the present invention: the setting process of the pressure acquisition array includes: The surface of the office chair cushion is divided into grids to obtain several grid points. A micro pressure acquisition point is set at each grid point, and all micro pressure acquisition points form a pressure acquisition array.

[0008] As a further aspect of the present invention: the process of obtaining the pressure distribution surface includes: A two-dimensional coordinate system is established on the surface of the cushion. The two-dimensional coordinates of each micro pressure acquisition point are obtained on the two-dimensional coordinate system. A three-dimensional coordinate system is obtained by establishing a Z-axis with pressure value as the coordinate value on the two-dimensional coordinate system. According to the pressure value collected by each micro pressure acquisition point, it is converted into each two-dimensional coordinate and its corresponding Z-axis coordinate value. Then, several three-dimensional coordinate points are obtained on the three-dimensional coordinate system, and all three-dimensional coordinate points constitute a pressure distribution surface.

[0009] As a further aspect of the present invention: the process of determining the pressure center of the contact area includes: Let the coordinates of the i-th micro pressure acquisition point be (x... i y i p i ), then the coordinates of the pressure center are P=(X c Y c ),in , where n is the total number of micro pressure acquisition points and i is the index.

[0010] As a further aspect of the present invention: the process of determining whether the pressure center has displacement includes: The coordinates of the pressure center are marked as pressure center coordinates. The pressure center coordinates are determined in real time to obtain the pressure center coordinates at each moment. The moment when the user just sat down is obtained and recorded as the starting moment, and the pressure center coordinates at the starting moment are obtained and recorded as the starting coordinates. If the pressure center coordinates at t consecutive moments satisfy... Where P0 is the starting coordinate, P i For the i-th time after the initial time, i∈[1,t-1], or for t consecutive time intervals, |P0-P t-1 If |≥d, where d is a preset displacement distance threshold, then it is determined that the pressure center has displacement.

[0011] As a further aspect of the present invention: the process of acquiring status data includes: Over a consecutive time interval t, obtain the displacement distance |P0-P t-1 | and obtain the pressure value corresponding to the pressure center at each time point in real time, obtain the average value of the pressure value, and record it as the equivalent pressure value; Within a consecutive time interval of t, each pair of adjacent time intervals forms a time interval, resulting in t-1 time intervals. The velocity v within each time interval is then obtained. k Let v represent the velocity in the k-th time interval; then, based on the velocities of every two adjacent time intervals, we obtain several accelerations a = |v|. k -v k-1 | / 2T, where T is the time interval between any two adjacent moments; obtain the average value of all accelerations, denoted as displacement acceleration.

[0012] As a further aspect of the present invention: the process of obtaining the average equivalent frictional force on the surface of the cushion includes: Obtain the total area A of the contact region shown, and set the friction coefficient μ. Then, the maximum static friction force F = μN is obtained, where N is the equivalent pressure value. The loss coefficient is then obtained. ,in , and , , Then the average equivalent frictional force F eq =(1-Loss)F.

[0013] As a further aspect of the present invention: the compensation force value F is obtained based on the average equivalent frictional force. comp =FF eq .

[0014] The beneficial effects of this invention are: This invention, by collecting pressure distribution data in real time and calculating the displacement of the pressure center, can keenly and accurately identify the initial downward trend of the user's body, thus proactively intervening and adjusting before discomfort occurs or in its early stages, achieving intelligent posture maintenance. Based on biomechanical principles, adaptive calculations ensure that each angle compensation directly corresponds to the actual degree of downward movement, providing just the right amount of support. This effectively suppresses downward movement while avoiding discomfort or interference from over-adjustment. Furthermore, automatically maintaining a stable posture effectively reduces muscle fatigue and static load in the user's lower back and back, lowering the risk of occupational musculoskeletal diseases caused by poor posture. Simultaneously, without requiring the user to manually adjust the chair, it ensures continuity and immersion in work, improving office comfort and productivity. Attached Figure Description

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram illustrating the steps of an office chair tilt angle adjustment method based on pressure distribution acquisition according to the present invention; Figure 2This is a flowchart illustrating a method for adjusting the tilt angle of an office chair based on pressure distribution data collection, according to the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1 As shown, this invention is a method for adjusting the tilt angle of an office chair based on pressure distribution data acquisition, comprising the following steps: Step S1: The area of ​​the user's buttocks and thighs that comes into contact with the office chair is recorded as the contact area; a pressure acquisition array is set on the surface of the office chair cushion, which is used to acquire the pressure applied by the user's contact area on the surface of the cushion in real time, and obtain the pressure distribution surface. In a preferred embodiment of the present invention, the setting process of the pressure acquisition array includes: The surface of the office chair cushion is divided into grids to obtain several grid points. A micro pressure acquisition point is set at each grid point, and all the micro pressure acquisition points form a pressure acquisition array. In a preferred embodiment of the present invention, the process of obtaining the pressure distribution surface includes: A two-dimensional coordinate system is established on the surface of the cushion. The two-dimensional coordinates of each micro pressure acquisition point are obtained on the two-dimensional coordinate system. A three-dimensional coordinate system is then established on the two-dimensional coordinate system with the pressure value as the coordinate value. The pressure value collected by each micro pressure acquisition point is converted into each two-dimensional coordinate and its corresponding Z-axis coordinate value. Several three-dimensional coordinate points are obtained on the three-dimensional coordinate system, and all three-dimensional coordinate points constitute a pressure distribution surface. Step S2: Based on the pressure distribution surface, determine the pressure center of the contact area in real time, and determine whether there is displacement of the pressure center. If there is displacement, obtain state data, which includes displacement distance, displacement acceleration and equivalent pressure value. In a preferred embodiment of the present invention, the process of determining the pressure center of the contact area includes: Let the coordinates of the i-th micro pressure acquisition point be (x... i y i p i ), then the coordinates of the pressure center are P=(X c Y c ),in , where n is the total number of micro pressure acquisition points, and i is the index; In a preferred embodiment of the present invention, the process of determining whether the pressure center has displacement includes: The coordinates of the pressure center are marked as pressure center coordinates. The pressure center coordinates are determined in real time to obtain the pressure center coordinates at each moment. The moment when the user just sat down is obtained and recorded as the starting moment, and the pressure center coordinates at the starting moment are obtained and recorded as the starting coordinates. If the pressure center coordinates at t consecutive moments satisfy... Where P0 is the starting coordinate, P i For the i-th time after the initial time, i∈[1,t-1], or for t consecutive time intervals, |P0-P t-1 If |≥d, where d is a preset displacement distance threshold, then it is determined that the pressure center has displacement; It is worth noting that the starting time mentioned in the context of t consecutive time intervals is the first time interval; In a preferred embodiment of the present invention, if the pressure center coordinates at consecutive times t do not satisfy... And does not satisfy |P0-P t-1 If |≥d, then it is determined that the pressure center has no displacement; In a preferred embodiment of the present invention, the process of acquiring status data includes: Over a consecutive time interval t, obtain the displacement distance |P0-P t-1 | and obtain the pressure value corresponding to the pressure center at each time point in real time, obtain the average value of the pressure value, and record it as the equivalent pressure value; Within a consecutive time interval of t, each pair of adjacent time intervals forms a time interval, resulting in t-1 time intervals. The velocity v within each time interval is then obtained. k Let v represent the velocity in the k-th time interval; then, based on the velocities of every two adjacent time intervals, we obtain several accelerations a = |v|. k -v k-1 | / 2T, where T is the time interval between any two adjacent moments; obtain the average value of all accelerations, denoted as displacement acceleration; Step S3: Based on the state data, obtain the average equivalent friction force of the pressure center on the surface of the seat cushion, obtain the compensation force value according to the average equivalent friction force, determine the seat cushion angle compensation value according to the compensation force value, and adjust the seat cushion angle of the office chair based on the seat cushion angle compensation value. In a preferred embodiment of the present invention, the process of obtaining the average equivalent friction force on the surface of the cushion includes: Obtain the total area A of the contact region shown, and set the friction coefficient μ. Then, the maximum static friction force F = μN is obtained, where N is the equivalent pressure value. The loss coefficient is then obtained. ,in , and , , Then the average equivalent frictional force F eq =(1-Loss)F; It should be noted that, The specific form is determined experimentally, and is usually as follows: , where min represents selecting the minimum value, and K1, K2, and K3 are all preset weight coefficients, and C is the preset base offset; The farther, faster, and more violently the descent, the greater the loss of friction is determined. It should be noted that the friction coefficient μ is obtained based on experiments and the principle of static equilibrium. Specifically, when the system is first started or a calibration command is received, the seat is adjusted to the standard sitting angle, and the user is prompted to keep their body upright and sit still. During the preset time when the user remains stable, the position of the pressure center is obtained, and the seat cushion tilt adjustment mechanism is controlled to slowly raise the front edge of the seat cushion at a very low speed until the pressure center is first detected to begin to move forward slightly. The system stops immediately and the critical tilt angle σ between the seat cushion and the horizontal plane is recorded at this moment. Then, μ = tan(σ). Furthermore, the basic offset C is obtained based on calibration experiments. The basic offset represents a basic friction loss benchmark value that objectively exists in the zero initial motion state due to factors such as the inherent creep characteristics of the seat cushion material and the initial static friction state between the user's clothing and the cushion surface. That is, when the user remains stationary, the soft seat cushion will also undergo slow plastic deformation under continuous pressure, resulting in a slight and continuous backward tilting tendency of the body. This inherent downward tilting tendency, which is not caused by active movement, needs to be quantified by C. In a preferred embodiment of the present invention, the compensation force value F is obtained based on the average equivalent frictional force. comp =FF eq ; Specifically, a compensation force value is obtained through simple subtraction, representing the amount by which the current anti-slip capability of the seat cushion decreases compared to its maximum potential; F comp The larger the value, the more severe the downward trend, meaning a greater loss of friction, and therefore a stronger angle adjustment intervention is required. In a preferred embodiment of the present invention, the seat cushion angle compensation value is determined based on the compensation force value. , where W is a preset calibration coefficient; It should be noted that W is a calibration coefficient related to seat size and user body shape characteristics, obtained based on calibration experiments. Specifically, in the calibration experiment, the tester sits on the seat in a standard sitting posture, and the total positive pressure and the position of the pressure center are recorded in the initial state. The seat cushion tilt angle is adjusted to several known small angles in sequence, and the compensation force value that is offset to keep the pressure center unchanged after each adjustment is measured or calculated. The calibration coefficient is obtained by fitting multiple sets of data. In a preferred embodiment of the present invention, the process of adjusting the seat cushion angle of the office chair includes obtaining the rotation axis between the seat cushion surface and the seat back of the office chair, rotating along the rotation axis, and increasing the angle θ between the seat cushion surface and the horizontal plane. It can be understood that when the front edge of the seat rises, that is, when the angle between the seat and the horizontal plane increases, it will generate an additional support force on the user's thigh that is perpendicular to the surface of the seat; one component of this support force, along the direction of the seat surface, can provide an additional friction force to resist slipping.

[0019] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for adjusting the tilt angle of an office chair based on pressure distribution data acquisition, characterized in that, Includes the following steps: Step S1: Record the area of ​​the user's buttocks and thighs that comes into contact with the office chair as the contact area; A pressure acquisition array is set on the surface of the seat cushion of an office chair. The pressure acquisition array is used to acquire the pressure applied by the user's contact area on the surface of the seat cushion in real time, and obtain a pressure distribution surface. Step S2: Based on the pressure distribution surface, determine the pressure center of the contact area in real time, and determine whether there is displacement of the pressure center. If there is displacement, obtain state data, which includes displacement distance, displacement acceleration and equivalent pressure value. Step S3: Based on the state data, obtain the average equivalent friction force of the pressure center on the surface of the seat cushion, obtain the compensation force value according to the average equivalent friction force, determine the seat cushion angle compensation value according to the compensation force value, and adjust the seat cushion angle of the office chair according to the seat cushion angle compensation value.

2. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The setup process for the pressure acquisition array includes: The surface of the office chair cushion is divided into grids to obtain several grid points. A micro pressure acquisition point is set at each grid point, and all micro pressure acquisition points form a pressure acquisition array.

3. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The process of obtaining the pressure distribution surface includes: A two-dimensional coordinate system is established on the surface of the cushion. The two-dimensional coordinates of each micro pressure acquisition point are obtained on the two-dimensional coordinate system. A three-dimensional coordinate system is obtained by establishing a Z-axis with pressure value as the coordinate value on the two-dimensional coordinate system. According to the pressure value collected by each micro pressure acquisition point, it is converted into each two-dimensional coordinate and its corresponding Z-axis coordinate value. Then, several three-dimensional coordinate points are obtained on the three-dimensional coordinate system, and all three-dimensional coordinate points constitute a pressure distribution surface.

4. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The process of determining the pressure center of the contact area includes: Let the coordinates of the i-th micro pressure acquisition point be (x... i y i p i ), then the coordinates of the pressure center are P=(X c Y c ),in , where n is the total number of micro pressure acquisition points and i is the index.

5. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The process of determining whether the pressure center has displacement includes: The coordinates of the pressure center are marked as pressure center coordinates. The pressure center coordinates are determined in real time to obtain the pressure center coordinates at each moment. The moment when the user just sat down is obtained and recorded as the starting moment, and the pressure center coordinates at the starting moment are obtained and recorded as the starting coordinates. If the pressure center coordinates at t consecutive moments satisfy... Where P0 is the starting coordinate, P i For the i-th time after the initial time, i∈[1,t-1], or for t consecutive time intervals, |P0-P t-1 If |≥d, where d is a preset displacement distance threshold, then it is determined that the pressure center has displacement.

6. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The process of obtaining status data includes: Over a consecutive time interval t, obtain the displacement distance |P0-P t-1 | and obtain the pressure value corresponding to the pressure center at each time point in real time, obtain the average value of the pressure value, and record it as the equivalent pressure value; Within a consecutive time interval of t, each pair of adjacent time intervals forms a time interval, resulting in t-1 time intervals. The velocity v within each time interval is then obtained. k Let v represent the velocity in the k-th time interval; then, based on the velocities of every two adjacent time intervals, we obtain several accelerations a = |v|. k -v k-1 | / 2T, where T is the time interval between any two adjacent moments; obtain the average value of all accelerations, denoted as displacement acceleration.

7. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The process of obtaining the average equivalent frictional force on the surface of the cushion includes: Obtain the total area A of the contact region shown, and set the friction coefficient μ. Then, the maximum static friction force F = μN is obtained, where N is the equivalent pressure value. The loss coefficient is then obtained. ,in ,and , , Then the average equivalent frictional force F eq =(1-Loss)F.

8. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The compensation force value F is obtained based on the average equivalent frictional force. comp =FF eq .

9. The method for adjusting the tilt angle of an office chair based on pressure distribution acquisition according to claim 1, characterized in that, The seat cushion angle compensation value is determined based on the compensation force value. , where W is a preset calibration coefficient.

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