Support reaction force calculation device and support reaction force calculation program

Abstract

To calculate a value of a support reaction force in accordance with the posture of a seated person.SOLUTION: One embodiment of the present disclosure is a support reaction force calculation device that uses a seated-posture mannequin and calculates at least one value of a support reaction force acting on a seated person and includes a support reaction force calculation unit. The support reaction force calculation unit is configured to calculate at least one value of a support reaction force to maintain the seated posture of the seated person on the basis of force equilibrium acting on a head block, force equilibrium acting on a chest block, force equilibrium acting on a lumbar spine block, force equilibrium acting on a lumbar block, force equilibrium acting on a thigh block and force equilibrium acting on a lower thigh block of the seated-posture mannequin.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a support reaction force calculation device and a support reaction force calculation program that calculate a support reaction force acting on a seated person sitting on a vehicle seat mounted on a vehicle.

Background Art

[0002] Patent Document 1 describes that by configuring a vehicle seat such that the spring constant at a position corresponding to the occupant's spine in the rib cage support portion on the surface of the seat back is less than or equal to the spring constant at a position corresponding to the occupant's spine in the hip bone support portion on the surface of the seat back, the occupant can naturally maintain an appropriate driving position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The sitting posture of a seated person on a vehicle seat can be measured by a sitting posture mannequin. However, in order to achieve the measured sitting posture, a support reaction force acting from the vehicle seat toward the occupant to maintain the sitting posture is required. However, the magnitude of this support reaction force varies depending on the posture of the occupant (for example, a standard posture, a hunched posture, or a swayback posture).

[0005] An object of the present disclosure is to calculate a value of a support reaction force according to the posture of a seated person.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a support reaction force calculation device (1) that calculates the value of at least one support reaction force acting on a seated person using a seating posture mannequin (PM) that represents the seating posture of the seated person sitting on a vehicle seat mounted on a vehicle, and includes a support reaction force calculation unit (S30).

[0007] The seating posture mannequin (PM) includes a head block (P1), a chest block (P2), a lumbar spine block (P3), a waist block (P4), a thigh block (P5), and a lower leg block (P6) that represent the head, chest, lumbar spine, waist, thighs, and lower legs of the seated person, respectively, and are regarded as rigid bodies. The head block (P1) is pin-connected to the chest block (P2). The chest block (P2) is pin-connected to the lumbar spine block (P3). The lumbar spine block (P3) is pin-connected to the waist block (P4). The waist block (P4) is pin-connected to the thigh block (P5). The thigh block (P5) is pin-connected to the lower leg block (P6).

[0008] The support reaction force calculation unit (S30) is configured to calculate the value of at least one support reaction force for maintaining the seating posture of the seated person based on the balance of forces acting on the head block (P1), the balance of forces acting on the chest block (P2), the balance of forces acting on the lumbar spine block (P3), the balance of forces acting on the waist block (P4), the balance of forces acting on the thigh block (P5), and the balance of forces acting on the lower leg block (P6).

[0009] The support reaction force calculation device (1) of the present disclosure configured as described above can calculate the value of the support reaction force according to the posture of the seated person. Another aspect of the present disclosure is a support reaction force calculation program (30) that calculates the value of at least one support reaction force acting on a seated person using a seating posture mannequin (PM) that represents the seating posture of the seated person sitting on a vehicle seat mounted on a vehicle.

[0010] Then, the reaction force calculation program (30) of the present disclosure causes a computer to function as a reaction force calculation unit (S30). The reaction force calculation program (30) of the present disclosure configured as described above can calculate the value of the reaction force according to the posture of the seated person.

[0011] In the reaction force calculation device (1) and the reaction force calculation program (30) of the present disclosure, at least one reaction force includes at least one of a head reaction force (F h ) acting on the head block (P1), a chest reaction force (F c ) acting on the chest block (P2), a lower thoracic reaction force (F lu ) acting on the upper part of the lumbar block (P3), an iliac reaction force (F p ) acting on the lower part of the lumbar block (P3), a ischial reaction force (F i ) acting on the hip block (P4), and a thigh reaction force (F t ) acting on the thigh block (P5).

[0012] Note that the signs in each of the above parentheses are an example showing the correspondence relationship with the specific configuration and the like described in the embodiments to be described later, and the present disclosure is not limited to the specific configuration and the like indicated by the signs in the above parentheses.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [1. First Embodiment] [1-1. Configuration of the support reaction force calculation device] As shown in FIG. 1, the support reaction force calculation device 1 of this embodiment includes a display unit 11, an operation input unit 12, a data storage unit 13, a data input / output unit 14, and a control unit 15. The support reaction force calculation device 1 calculates the value of at least one support reaction force acting on a seated person sitting on a vehicle seat mounted on a vehicle.

[0015] The display unit 11 includes a display device (not shown) and displays various images on the display screen of the display device. The operation input unit 12 outputs input operation information for identifying an input operation performed by a user via a keyboard and a mouse (not shown).

[0016] The data storage unit 13 is a storage device for storing various data. The data input / output unit 14 performs data input / output with an external device connected by wire or wirelessly.

[0017] The control unit 15 is mainly configured by a well-known microcomputer including a CPU 21, a ROM 22, a RAM 23, etc. Various functions of the microcomputer are realized by the CPU 21 executing a program stored in a non-transitory tangible recording medium. In this example, the ROM 22 corresponds to the non-transitory tangible recording medium storing the program. Also, by executing this program, a method corresponding to the program is executed. Note that part or all of the functions executed by the CPU 21 may be configured hardware-wise by one or a plurality of ICs or the like. Also, the number of microcomputers constituting the control unit 15 may be one or a plurality.

[0018] [1-2. Support reaction force calculation method] Next, a method for calculating the support reaction force will be described. Considering simplifying the human body into the minimum necessary elements to represent the sitting state, as shown in FIG. 2, the sitting posture mannequin PM of the present embodiment is divided into six blocks: a head block P1, a chest block P2, a lumbar block P3, a waist block P4, a thigh block P5, and a lower leg block P6. Each block is regarded as a rigid body. On the back surface of each rigid body of the present embodiment, the sitting rear surface shape corresponding to the 50th percentile of American men is set as a rigid surface. The rigid surface is divided by the chest block P2, the lumbar block P3, the waist block P4, and the thigh block P5. In particular, the lumbar block P3 is divided into four parts so as to smoothly follow the curvature of the lumbar spine.

[0019] Regarding the head block P1, it is pin-connected to the chest block P2 at the base of the cervical vertebra A. The pin connection in the present embodiment is a rotational joint having freedom in the pitch direction. Regarding the chest block P2, it is pin-connected to the lumbar block P3 at the upper part of the base of the lumbar vertebra B.

[0020] Regarding the lumbar block P3, it is pin-connected to the waist block P4 at the lower part of the base of the lumbar vertebra C. Regarding the waist block P4, it is pin-connected to the thigh block P5 at the hip joint D.

[0021] Regarding the thigh block P5, it is pin-connected to the lower leg block P6 at the knee joint E. Regarding the lower leg block P6, it is pin-connected to the foot at the ankle joint F.

[0022] Then, the support reaction force required to maintain the sitting posture of the sitting posture mannequin PM is obtained from the balance of static forces. In the model of this embodiment, it is assumed that the seated posture mannequin PM is pin-supported in the vehicle coordinate system by the ischium G, and the balance of forces of six rigid bodies, namely the head block P1, the chest block P2, the lumbar block P3, the lumbar region block P4, the thigh block P5, and the lower leg block P6, is considered. In the model of this embodiment, by considering one external force acting point for each rigid body, it is treated as a statically determinate problem. Also, friction is a non-linear phenomenon with path dependence. In the model of this embodiment, friction is considered only at the lumbar region block P4. Since the friction at the thigh block P5 and the chest block P2 is reduced during the sitting process, it is assumed to be negligible. Furthermore, it is assumed that the thigh block P5 is supported sufficiently by the cushion reaction force, and only the force due to the weight of the lower leg block P6 is input from the lower leg through the knee joint E. This means that the posture is not maintained by active muscle strength (i.e., not pushing with the feet).

[0023] Based on the above, the equilibrium equations of each rigid body are considered as follows. As shown in FIG. 3, for the head block P1, the head support reaction force F h acts on the head center of gravity CG1.

[0024] For the chest block P2, the chest support reaction force F c acts on the chest center of gravity CG2. For the lumbar block P3, the lower thoracic support reaction force F lu acts on the upper part of the lumbar spine root B.

[0025] For the lumbar region block P4, the iliac support reaction force F p acts on the lower part of the lumbar spine root C (i.e., the ilium). For the thigh block P5, the thigh support reaction force F t acts on the thigh center of gravity CG5. Also, the knee joint reaction force R le acts on the knee joint E. This means that the thigh block P5 is supported by the iliac support reaction force F p (i.e., it is not assumed that the lower leg pushes and the thigh floats from the cushion), and the lower leg angle θle Knee joint reaction force R corresponding to le is a model in which only the force acts from the knee.

[0026] Regarding the lower leg block P6, the knee joint reaction force R acts on the knee joint E. le acts. For the head block P1 of the sitting posture mannequin PM, the force balance equations are represented by equations (1), (2), and (3). Equation (1) is the force balance equation acting in the vertical direction. Equation (2) is the force balance equation acting in the horizontal direction. Equation (3) is the moment balance equation.

[0027] In equations (1) to (3), θ h is the angle formed by the line segment connecting the head center of gravity CG1 and the base of the cervical vertebra A and the gravity line. m h is the mass of the head block P1 (hereinafter, the head mass). R hv is the reaction force acting vertically on the base of the cervical vertebra A (hereinafter, the vertical reaction force at the base of the cervical vertebra). R hh is the reaction force acting horizontally on the base of the cervical vertebra A (hereinafter, the horizontal reaction force at the base of the cervical vertebra). l hg is the distance between the base of the cervical vertebra A and the head center of gravity CG1.

[0028]

Equation

[0029] For the chest block P2 of the sitting posture mannequin PM, the force balance equations are represented by equations (4), (5), and (6). Equation (4) is the force balance equation acting in the vertical direction. Equation (5) is the force balance equation acting in the horizontal direction. Equation (6) is the moment balance equation.

[0030] In equations (4) to (6), θ c is the angle formed by the line segment connecting the upper part of the base of the lumbar vertebra B and the base of the cervical vertebra A and the gravity line. θ cg is the angle formed by the line segment connecting the chest center of gravity CG2 and the upper part of the base of the lumbar vertebra B and the gravity line. m cis the mass of the chest block P2 (hereinafter referred to as the chest mass). R cv is the reaction force acting in the vertical direction with respect to the upper lumbar root B (hereinafter referred to as the upper lumbar root vertical reaction force). R ch is the reaction force acting in the horizontal direction with respect to the upper lumbar root B (hereinafter referred to as the upper lumbar root horizontal reaction force). l c is the distance between the upper lumbar root B and the cervical root A. l cg is the distance between the upper lumbar root B and the chest center of gravity CG2.

[0031]

Number

[0032] For the lumbar block P3 of the seated posture mannequin PM, the force balance equations are represented by equations (7), (8), and (9). Equation (7) is the force balance equation acting in the vertical direction. Equation (8) is the force balance equation acting in the horizontal direction. Equation (9) is the moment balance equation.

[0033] In equations (7) to (9), θ lu is the angle formed by the line segment connecting the upper lumbar root B and the lower lumbar root C and the gravity line. R luv is the reaction force acting in the vertical direction with respect to the lower lumbar root C (hereinafter referred to as the lower lumbar root vertical reaction force). R luh is the reaction force acting in the horizontal direction with respect to the lower lumbar root C (hereinafter referred to as the lower lumbar root horizontal reaction force). l lu is the distance between the lower lumbar root C and the upper lumbar root B.

[0034]

Number

[0035] For the lower leg block P6 of the seated posture mannequin PM, the force balance equation is represented by equation (10). Equation (10) is the moment balance equation. In equation (10), θ leis the angle formed by the line segment connecting the knee joint E and the ankle joint F and the line of gravity. m le is the mass of the lower leg block P6 (hereinafter referred to as the lower leg mass). R le is the reaction force acting on the knee joint E (hereinafter referred to as the knee joint reaction force). l le is the distance between the ankle joint F and the knee joint E. l leg is the distance between the ankle joint F and the center of gravity CG6 of the lower leg.

[0036]

Number

[0037] For the thigh block P5 of the seated posture mannequin PM, the force equilibrium equations are represented by Equation (11), Equation (12), and Equation (13). Equation (11) is the force equilibrium equation acting in the vertical direction. Equation (12) is the force equilibrium equation acting in the horizontal direction. Equation (13) is the moment equilibrium equation.

[0038] In Equations (11) to (13), θ t is the angle formed by the line segment connecting the hip joint D and the knee joint E and the horizontal line. m t is the mass of the thigh block P5 (hereinafter referred to as the thigh mass). R tv is the reaction force acting vertically on the hip joint D (hereinafter referred to as the hip joint vertical reaction force). R th is the reaction force acting horizontally on the hip joint D (hereinafter referred to as the hip joint horizontal reaction force). l t is the distance between the knee joint E and the hip joint D. l tg is the distance between the hip joint D and the center of gravity CG5 of the thigh.

[0039]

Number

[0040] Regarding the waist block P4 of the sitting posture mannequin PM, the force balance equations are represented by equations (14), (15), and (16). Equation (14) is the force balance equation acting in the vertical direction. Equation (15) is the force balance equation acting in the horizontal direction. Equation (16) is the moment balance equation.

[0041] In equations (14) to (16), θ p is the angle formed by the line segment connecting the ischium G and the lower part of the lumbar spine root C and the gravity line. θ pg is the angle formed by the line segment connecting the ischium G and the lower part of the lumbar spine root C and the line segment connecting the ischium G and the waist center of gravity CG4. θ hp is the angle formed by the line segment connecting the ischium G and the hip joint D and the gravity line. m p is the mass of the waist block P4 (hereinafter referred to as the waist mass). R pv is the reaction force acting in the vertical direction with respect to the ischium G (hereinafter referred to as the ischium vertical reaction force). R ph is the reaction force acting in the horizontal direction with respect to the ischium G (hereinafter referred to as the ischium horizontal reaction force). l p is the distance between the ischium G and the lower part of the lumbar spine root C. l pg is the distance between the ischium G and the waist center of gravity CG4. l hp is the distance between the ischium G and the hip joint D. μ is the coefficient of friction.

[0042]

Number

[0043] From equations (1) to (16), the head support reaction force F h , the cervical root horizontal reaction force R hh , and the cervical root vertical reaction force R hv are respectively represented by equations (17), (18), and (19).

[0044]

Number

[0045] The chest support reaction force F c, the horizontal reaction force R at the upper end of the lumbar spine ch , the vertical reaction force R at the upper end of the lumbar spine cv are respectively represented by equations (20), (21), and (22).

[0046]

Number

[0047] The supporting reaction force F at the lower part of the chest lu , the horizontal reaction force R at the lower end of the lumbar spine luh , the vertical reaction force R at the lower end of the lumbar spine luv , the knee joint reaction force R le are respectively represented by equations (23), (24), (25), and (26).

[0048]

Number

[0049] The thigh support reaction force F t , the hip joint horizontal reaction force R th , the hip joint vertical reaction force R tv are respectively represented by equations (27), (28), and (29).

[0050]

Number

[0051] The iliac support reaction force F p , the ischial horizontal reaction force R ph , the ischial vertical reaction force R pv are respectively represented by equations (30), (31), and (32).

[0052]

Number

[0053] The ischial support reaction force F supporting the ischium G i is represented by equation (33).

[0054] [Number]

[0055] [1 - 3. Support reaction force calculation process] Next, the procedure of the support reaction force calculation process executed by the control unit 15 will be described. The support reaction force calculation process is executed by activating the support reaction force calculation program 30 stored in the data storage unit 13 by the user's input operation for executing the support reaction force calculation process. Note that the support reaction force calculation program 30 may be installed in the support reaction force calculation device 1 in advance, or may be installed via a recording medium or a network. Examples of the recording medium include an optical disk, a magnetic disk, and a semiconductor memory.

[0056] When the support reaction force calculation process is executed, the CPU 21 of the control unit 15 displays, as shown in FIG. 4, an image for inputting various parameters (hereinafter, parameter input image) on the display screen of the display unit 11 at S10.

[0057] The various parameters input within the parameter input image are the above-mentioned head mass m h , chest mass m c , waist mass m p , thigh mass m t , lower leg mass m le , distance l hg , distance l c , distance l cg , distance l lu , distance l p , distance l pg , distance l hp , distance l t , distance l tg , distance l le , distance l leg , angle θ h , angle θ c , angle θ cg , angle θ lu , angle θ p , angle θ pg , angle θ hp , angle θ t , angle θ le and so on.

[0058] The CPU 21 determines, at S20, whether all of the various parameters have been input from the operation input unit 12. Here, if there are parameters that have not been input, the process at S20 is repeated to wait until all of the various parameters are input. Then, when all of the various parameters are input, the CPU 21 calculates the values of a plurality of support reaction forces using the above equations (17) to (33) at S30. The plurality of support reaction forces include the above head support reaction force F h , chest support reaction force F c , lower rib cage support reaction force F lu , iliac support reaction force F p , ischial support reaction force F i , thigh support reaction force F t .

[0059] The CPU 21 displays the values of the plurality of support reaction forces calculated at S30 on the display screen of the display unit 11 at S40, and ends the support reaction force calculation process. [1-4. Effects] According to the embodiment described in detail above, the following effects can be obtained.

[0060] (1a) The support reaction force calculation device 1 and the support reaction force calculation program 30 can calculate the value of the support reaction force according to the posture of the seated person. (1b) The support reaction force calculation device 1 and the support reaction force calculation program 30 can calculate the values of the head support reaction force F h , chest support reaction force F c , lower rib cage support reaction force F lu , iliac support reaction force F p , ischial support reaction force F i and thigh support reaction force F t .

[0061] [1-5. Corresponding relationships of expressions] In the embodiment described above, S30 corresponds to the process as the support reaction force calculation unit. [2. Other embodiments] Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment and can be implemented with various modifications.

[0062] (2a) The plurality of functions of one component in the above embodiment may be realized by a plurality of components, or one function of one component may be realized by a plurality of components. Further, the plurality of functions of a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of another above embodiment.

Description of Reference Numerals

[0063] 1…Support reaction force calculation device, 30…Support reaction force calculation program, P1…Head block, P2…Chest block, P3…Lumbar block, P4…Waist block, P5…Thigh block, P6…Lower leg block, PM…Seated posture mannequin

Claims

1. A support reaction force calculation device that calculates the value of at least one support reaction force acting on a seated person using a seating posture mannequin that represents the seating posture of the seated person sitting on a vehicle seat mounted on a vehicle, The seating posture mannequin includes a head block, a chest block, a lumbar spine block, a waist block, a thigh block, and a lower leg block that represent the head, chest, lumbar spine, waist, thigh, and lower leg of the seated person, respectively, and are regarded as rigid bodies. The head block is pin-connected to the chest block, the chest block is pin-connected to the lumbar spine block, the lumbar spine block is pin-connected to the waist block, the waist block is pin-connected to the thigh block, and the thigh block is pin-connected to the lower leg block, A support reaction force calculation device (1) comprising a support reaction force calculation unit configured to calculate the value of the at least one support reaction force for maintaining the seating posture of the seated person based on the balance of forces acting on the head block, the balance of forces acting on the chest block, the balance of forces acting on the lumbar spine block, the balance of forces acting on the waist block, the balance of forces acting on the thigh block, and the balance of forces acting on the lower leg block.

2. The support reaction force calculation device according to claim 1, The at least one support reaction force is, A support reaction force calculation device including at least one of a head support reaction force acting on the head block, a chest support reaction force acting on the chest block, a lower rib cage support reaction force acting on the upper part of the lumbar spine block, an iliac support reaction force acting on the lower part of the lumbar spine block, an ischial support reaction force acting on the waist block, and a thigh support reaction force acting on the thigh block.

3. A support reaction force calculation program that calculates the value of at least one support reaction force acting on a seated person using a seating posture mannequin that represents the seating posture of the seated person sitting on a vehicle seat mounted on a vehicle, The sitting posture mannequin includes a head block, a chest block, a lumbar spine block, a waist block, a thigh block, and a lower leg block that represent the head, chest, lumbar spine, waist, thigh, and lower leg of the seated person, respectively, and are regarded as rigid bodies. The head block is pin-connected to the chest block, the chest block is pin-connected to the lumbar spine block, the lumbar spine block is pin-connected to the waist block, the waist block is pin-connected to the thigh block, and the thigh block is pin-connected to the lower leg block. A computer is configured as a support reaction force calculation unit that calculates the value of the at least one support reaction force for maintaining the sitting posture of the seated person based on the balance of forces acting on the head block, the balance of forces acting on the chest block, the balance of forces acting on the lumbar spine block, the balance of forces acting on the waist block, the balance of forces acting on the thigh block, and the balance of forces acting on the lower leg block. A support reaction force calculation program for causing the computer to function as such.

4. The support reaction force calculation program according to claim 3, wherein the at least one support reaction force is a support reaction force calculation program including at least one of a head support reaction force acting on the head block, a chest support reaction force acting on the chest block, a lower rib cage support reaction force acting on the upper part of the lumbar spine block, an iliac support reaction force acting on the lower part of the lumbar spine block, an ischial support reaction force acting on the waist block, and a thigh support reaction force acting on the thigh block.

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