JP4052825B2 - Seated running fatigue evaluation method, vehicle seat evaluation method, and vehicle seat evaluation simulator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seating travel fatigue level evaluation method for evaluating the fatigue level of a human body seated on a vehicle seat in a running state, a vehicle seat evaluation method and a vehicle seat evaluation simulator using the seating travel fatigue level.
[0002]
[Prior art]
In order to improve the comfort when the vehicle is running, the development of a seat that does not get tired even if it is driven for a long time is required. In particular, reducing physical fatigue such as back pain has a great effect on improving the ride comfort of the vehicle seat. Since comfort such as sitting comfort is a human sense, a technique is adopted in which the subject is actually seated on the prototype sheet and the vehicle is driven, and the seating feeling and fatigue feeling are written on the evaluation sheet after traveling, Such evaluation tends to depend on the subjectivity of the subject, and there is a problem that the reliability of the evaluation result is low. In bioengineering, it has been well known to use surface electromyogram or body pressure distribution measurement for evaluation of physical fatigue. There arises a problem that it is difficult to obtain the degree of fatigue of the human body due to proper sitting and running.
Furthermore, the sensory evaluation of the vehicle seat is performed by analyzing the seating running fatigue degree evaluated in some way and the cushion characteristics such as the deflection amount and vibration characteristic of the vehicle seat used for the evaluation. However, it has not been realized because there is no technology for evaluating the fatigue level of sitting and running with reliability in spite of a simple method.
[0003]
[Problems to be solved by the invention]
In view of the above situation, an object of the present invention is to elucidate a physical fatigue mechanism exerted on a human body seated on a vehicle seat in a running state, and to evaluate a seating running fatigue degree by a simple method, and such seating. It is to provide a sensual evaluation technique for a vehicle seat using a running fatigue evaluation technique.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, a seating running fatigue evaluation method according to the present invention includes a step of measuring a cushion characteristic generated in a vehicle seat when a human body is seated, and a vibration characteristic of the human body and / or seat in the vehicle running state. measuring a, Ri Do and a step of quantitatively calculating the degree of fatigue of the seated traveling of the human body from the vibration characteristics and the cushion characteristics, in the cushion property and the amount of deflection of the portion corresponding to the vicinity of the human body back It includes deflection amount of the portion corresponding to the vicinity of the human body of the thigh, is the vibration characteristic that includes the vertical acceleration of the lateral acceleration change rate and a sheet of a human head.
[0005]
In this way, the cushion characteristics caused to the vehicle seat when the human body is seated, i.e. the human body - deflection of the portion as a static measurement of the sheet based corresponds to the vicinity of the human body back and body in the vicinity of thigh deflection amount of the portion corresponding to the human body or a sheet or vibration characteristics of both the vehicle running state, that is the human body - a vertical acceleration of the lateral acceleration change rate and the seat of the body of the head as a dynamic measure of the seat system Acquired, and from these measured quantities, the fatigue level of the seated running of the human body is quantitatively calculated. In calculating the fatigue level, for example, neural network modeling that inputs these measured quantities and outputs the fatigue level is used, or an algorithm obtained from a correlation analysis between these measured quantities and the fatigue level is used. It is possible to use.
[0006]
In one preferred embodiment of the present invention, in the calculating step, an arithmetic expression determined by a statistical method is used from the fatigue level of the seating travel measured for the human body, the cushion characteristic, and the vibration characteristic. . In other words, the fatigue level can be obtained very easily and quickly by adopting a multivariate function of the fatigue level with the cushion characteristics (static measured quantity) and the vibration characteristics (dynamic measured quantity) as variables. Will be.
[0007]
As a typical example of an arithmetic expression determined by a statistical method, there is a multiple regression expression obtained by multiple regression analysis using the cushion characteristic and the vibration characteristic as explanatory variables and the fatigue level as an objective variable. If a measurement amount that gives a sufficiently high contribution rate is selected as an explanatory variable, a highly reliable seating fatigue evaluation can be realized.
[0008]
The measurement amount included in the cushion characteristic and the vibration characteristic that greatly affects the seating running fatigue level of the human body is selected through experiments by the inventor and analysis of the experiment result. It was. That is, in a preferred embodiment of the present invention, the lateral acceleration change rate of the human head is measured in the 2 to 4 Hz region, and the vertical acceleration of the seat is measured in the 1 to 2 Hz region. Furthermore, the amount of adrenaline secretion fluctuation is adopted as an objective evaluation of the degree of fatigue of the human body.
[0009]
If the seating running fatigue level of a human body seated on a specific vehicle seat can be obtained with high reliability by the method as described above, the sensory evaluation of the vehicle seat can be performed from the obtained fatigue level. . By changing the material characteristics and design characteristics of the vehicle seat so that the degree of fatigue is as small as possible, an optimal seat can be developed.
[0010]
In addition, when each characteristic of the vehicle seat is substantially determined, the vehicle running vibration state used when measuring the dynamic measurement amount, such as the suspension system, is sequentially changed so as to reduce the fatigue level. By finding suspension conditions with low seating travel fatigue, it is possible to evaluate suspension systems optimally and contribute to the development of comfortable vehicles.
[0011]
As a vehicle seat evaluation simulator using the above-described fatigue evaluation, in the present invention, the seated travel fatigue evaluation formula obtained in advance by the above-described seated travel fatigue evaluation method, and when the human body is seated A displacement sensor for measuring a deflection amount of a portion corresponding to the vicinity of the back of the human body generated in the vehicle seat and a deflection amount of a portion corresponding to the vicinity of the thigh of the human body as cushion characteristics, and the vehicle seat in the vehicle running state a vibration device to an acceleration sensor for measuring the left right jerk and top and bottom acceleration of the seat of the human head in the vehicle running state as the vibration characteristics, a measured both deflection amount and lateral jerk commentary performing an arithmetic unit for calculating the degree of fatigue of a human body seated traveling from the vertical acceleration using the seating travel fatigue evaluation formula, the evaluation of the vehicle seat from the calculation result of the arithmetic unit That a part is proposed. In this vehicle seat evaluation simulator, the running state of the vehicle seat is freely created by the vibration device, the static measurement amount described above is acquired by a displacement sensor, and the dynamic measurement amount described above is acquired by an acceleration sensor. The arithmetic unit stores an arithmetic expression for deriving the seating running fatigue degree from the static measurement amount and the dynamic measurement amount. By performing a simulation by sequentially replacing a plurality of different vehicle seats, the comfort between these vehicle seats can be evaluated. In addition, it is possible to evaluate the vehicle structure, particularly the suspension system, by evaluating the degree of fatigue while arbitrarily changing the running state by the vibration device, and this evaluation simulator also functions as a suspension evaluation simulator. Become.
Other features and advantages of the present invention will become apparent from the following description of embodiments using the drawings.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a vehicle seat evaluation simulator to which a seating travel evaluation method and a vehicle seat evaluation method according to the present invention are applied. This simulator gives a pedestal 1, a driving unit 2 attached to the pedestal 1, a vehicle seat (hereinafter simply referred to as a seat) 3 attached to the pedestal 1, and a vibration similar to the vehicle running state. A three-axis vibration device 4 and a controller 5 that controls the vibration device 4 while displaying a traveling scene on the display 6 in accordance with the steering state in the driving unit 2 are provided.
[0013]
As shown in FIG. 2, the seat 3 includes a back portion 3a, a cushion portion 3b, and a headrest 3c. When necessary, the seat 3 is used for a vehicle when a human body as a subject is seated. A first displacement sensor 8a for measuring a deflection amount of a portion of the vehicle seat corresponding to the vicinity of the back of the human body that is generated when the human body is seated is attached to the back portion 3a as the displacement sensor 8 that measures the cushion characteristics generated in the seat. The second displacement sensor 8b for measuring the amount of deflection of the portion corresponding to the vicinity of the thigh of the human body is attached to the cushion portion 3b. Further, as the acceleration sensor 7 for measuring the vibration characteristics of the subject and the seat 3 in the vehicle running state, the first acceleration sensor 7a and the cushion portion 2 are attached to the head of the subject sitting on the seat 3 and measure the lateral acceleration. Is provided with a second acceleration sensor 7b for measuring the vertical acceleration.
[0014]
The driving unit 2 is provided with a steering wheel 21 and, if necessary, a brake, an accelerator, and the like. Further, the driving unit 2 detects a movement of the vehicle steering device to generate a steering signal and transmits the steering signal to the controller 5. A generator 22 is provided.
[0015]
The controller 5 is configured with a microcomputer as a core element, and through the I / O interface 50, various operation inputs other than the acceleration sensor 7, the displacement sensor 8, the steering signal generator 22, the display 6 and the like described above. Connected to an operation input device 9 such as a keyboard and a printer. Further, in order to send an operation control signal to the vibration device 4, the controller 40 of the vibration device 4 is also connected.
[0016]
As is well known, such a controller 5 realizes various functions by the operation of the CPU by a program stored in a ROM, a RAM or the like, that is, by hardware or software (program). As shown in FIG. 3, the function related to is whether or not to provide a running state to the seat 3 through this simulator in response to a signal from the operation input device 9 or the control signal generator 22. An operation condition setting unit 51 for setting the vibration, and a vibration for giving a control signal to the controller 40 of the vibration device 4 to drive the vibration device 4 so as to exert vibrations suitable for the set operation condition on the seat 3 mounted on the base 1 Device control unit 52, sensor signal processing unit 53 for processing signals from acceleration sensor 7 and displacement sensor 8, and seating described in detail later A seating running fatigue level calculation unit 54 that calculates the fatigue level of the subject by applying the sensor signal processing result obtained by the sensor signal processing unit 53 to a calculation algorithm (calculation formula) for the row fatigue level, and the calculated fatigue level A seat evaluation unit 55 that evaluates a seat that is a test target, and a travel scene generation unit 56 that generates a travel scene displayed on the display 6 based on the control signal sent from the control signal generator 22.
[0017]
Next, how to obtain an arithmetic expression for calculating the degree of fatigue experienced by a subject in seated travel from the cushion characteristics of the seat 3 and vibration characteristics generated in the seat 3 in the running state, which is an important feature of the present invention, will be described in detail.
[0018]
In the present invention, the secretion of adrenaline (catecholamine), which is a type of stress hormone, is used as an index for quantitatively determining the fatigue accumulated in the subject seated on the seat 3 during vehicle travel rather than subjectively as in the prior art. We are using. Therefore, the subject first relaxes in an easy chair for 60 minutes to measure the amount of adrenaline secretion in a resting state, and immediately after that, collects urine. Next, the user sits on the seat 3 to be evaluated, which is attached to the simulator described above, creates a vehicle running state corresponding to a predetermined driving condition, and performs a seating running simulation for 60 minutes. The vibration characteristics generated in the human body or the seat 3 as the subject in the vehicle running state are measured several times. Further, before the seating run simulation (although it can be performed later), the cushion characteristic generated in the seat 3 when the subject is seated is measured. After completion of the seating run simulation, urine collection is performed immediately in order to measure the adrenaline secretion of the subject after receiving such a seating run load. Therefore, the difference in adrenaline secretion before and after the seating run simulation is regarded as the degree of fatigue experienced by the subject by the seating run.
[0019]
When the driving conditions are constant with respect to the characteristic amount representing the degree of fatigue, that is, the difference in adrenaline secretion before and after the seating run simulation, the above-mentioned cushion characteristics and vibration characteristics are considered to be influential factors. The amount of deflection of the part corresponding to the vicinity of the back of the human body, the amount of deflection of the part corresponding to the vicinity of the thigh, the amount of deflection of the part corresponding to the vicinity of the waist, etc. The vertical acceleration, longitudinal acceleration, or acceleration change rate of the head and waist in the frequency domain, and the vertical acceleration, longitudinal acceleration, or acceleration change rate in various vibration frequency domains in each part of the seat 3 are also exemplified. By examining the correlation between various cushion characteristics and vibration characteristics with respect to the fatigue level from the data obtained through the seating running simulation, a fatigue evaluation formula for deriving the fatigue degree from the cushion characteristics and the vibration characteristics can be created.
[0020]
Next, a procedure for creating a fatigue evaluation formula will be described with reference to the flowchart of FIG. Here, in the creation of the evaluation formula, a method of multiple regression analysis is used with the cushion characteristic and the vibration characteristic as explanatory variables and the adrenaline fluctuation amount as an objective variable. Further, the above-described simulator can be used to set the seat 3 to be evaluated to the vehicle running state.
[0021]
First, as a static measurement amount, the above-described cushion characteristic for the evaluation target seat 3 is measured (# 2). Urine is collected from a subject who has been sufficiently rested, and the amount of adrenaline secretion before sitting and running is measured (# 4). The subject is seated on the evaluation target sheet 3 mounted on the simulator (# 5), and the simulator is started (# 8). As a result, a sitting / running simulation is created, and the above-described vibration characteristic is measured as a dynamic measurement amount at a predetermined timing (# 10). When the planned measurement amount is obtained, the simulator is stopped and the seating running simulation is terminated (# 12). Immediately, urine is collected from the subject, and the amount of adrenaline secretion after sitting and running is measured (# 14). The measured amount relating to the acquired cushion characteristic, the measurement amount relating to the vibration characteristic, and the adrenaline fluctuation amount obtained by subtracting the adrenaline secretion amount before sitting running from the adrenaline secretion amount after sitting running are stored as a measurement data file (# 16). . Such a measurement process is performed for all sheets 3 having different specifications (# 18).
[0022]
Once a data file relating to cushion characteristics and vibration characteristics as explanatory variables and a data file relating to adrenaline variation as objective variables are created, multiple regression analysis is performed using these data files. First, an item used as an explanatory variable is selected from a data file relating to cushion characteristics and vibration characteristics (# 20). Next, the regression coefficient of the multiple regression equation is calculated using a well-known multiple regression analysis algorithm (# 22), and the obtained multiple regression equation is tested (# 24). The multiple regression analysis as described above is repeatedly performed while selecting from a plurality of explanatory variable candidates (# 26). Various methods are known as a method for selecting the optimum explanatory variable from a plurality of explanatory variable candidates. For example, a regression model for every combination is examined from a plurality of explanatory variable candidates. The brute force method, starting from the case where no explanatory variable is included, and the forward selection method in which the explanatory variable is incremented one by one, starting from a state where all the explanatory variable candidates are included, one explanatory variable Arbitrary methods such as a receding erasing method for decreasing each time and a sequential method for increasing or decreasing the explanatory variable can be adopted. When the multiple regression analysis based on the selection of possible explanatory variables is completed, the multiple regression equation having the highest contribution rate is specified from the analysis result and adopted as the seating running fatigue evaluation equation (# 28).
[0023]
The seating running fatigue evaluation formula obtained from the experimental results by the inventors of the present application and used in this embodiment is as follows, and as an explanatory variable, the deflection amount of the portion corresponding to the vicinity of the back of the human body: X1, deflection amount of the part corresponding to the vicinity of the thigh of the human body: X2, lateral acceleration change rate in the 2 to 4 Hz region of the head of the human body: X3, vertical acceleration in the 1-2 Hz region of the seat: X4 Of course, the objective variable is adrenaline fluctuation amount: Y.
In other words, the sitting running fatigue level (adrenaline fluctuation) is
Y = a.X1 + b.X2 + c.X3 + d.X4 + .epsilon.
Where ε is the adjustment value,
The coefficients are a = −5, b = 200, c = −0.05, d = −. However, the present invention is not limited to these numerical values.
[0024]
The important points regarding the seat design obtained from the seating running fatigue evaluation formula are that the low frequency component of vibration generated in the cushion portion 3b of the seat 3 is reduced, the portion corresponding to the vicinity of the back of the seated person and the thigh The amount of deflection of the part corresponding to the vicinity of the part is increased.
[0025]
Next, a seat evaluation procedure using a vehicle seat evaluation simulator in which the above-described seating travel fatigue level evaluation formula is incorporated in the seating travel fatigue level calculation unit 54 of the controller 5 will be described with reference to the flowchart of FIG. First, the evaluation target sheet 3 is selected (# 52), and the selected sheet 3 is mounted on the pedestal 1 of the simulator (# 54). The subject gets into the simulator, sits on the seat 3 that is mounted, and the first displacement sensor 8a measures the deflection amount X1 of the portion corresponding to the vicinity of the subject's back, while the second displacement sensor 8b measures the thigh of the subject. The deflection amount X2 of the portion corresponding to the vicinity of the portion is measured (# 56).
[0026]
Next, an operating condition for vibrating the pedestal 1 is set for the vibration device 4 so that the mounted seat 3 is in a specific vehicle running state (# 58). The subject is seated on the seat 3 (# 60), the simulator is activated, and the seat 3 and the subject are brought into the seated running state (# 62). In this sitting and running state, the lateral acceleration of the head is measured by the first acceleration sensor 7a attached to the subject's head, and the vertical acceleration of the cushion portion 2 is measured by the second acceleration sensor 7b. Through this measurement process, the sensor signal processor 53 determines the lateral acceleration change rate X3 in the 2-4 Hz region of the head and the vertical acceleration X4 in the 1-2 Hz region of the seat (# 64). When the measurement is completed, the simulator is stopped (# 66), and the seating running fatigue degree calculation unit 54 uses the two deflection amounts obtained in step # 56, the lateral acceleration change rate and the vertical acceleration obtained in step # 64. Then, the degree of adrenaline fluctuation, that is, the degree of sitting running fatigue is calculated from the above-described seating running fatigue level evaluation formula (# 68).
[0027]
Furthermore, if another driving condition such as a highway driving state, a city driving state, an off-road driving state, etc. is selected (# 70), the process returns to step # 58 again to calculate the seating driving fatigue level under different driving conditions. Repeat routine. If there is no further operating condition to be selected, it is checked whether another evaluation target sheet 3 exists (# 72), and when a new evaluation target sheet 3 is selected, the process returns to step # 52 again, and a different evaluation target is selected. The seating running fatigue level calculation routine is repeated with the seat 3. When there is no evaluation target sheet 3 to be newly selected, the seat evaluation unit 55 evaluates the evaluation target seat 3 based on the seating running fatigue degree obtained so far, and if necessary, outputs the evaluation list with a printer or the like. (# 74).
[0028]
In the above-described embodiment, the technical contents for evaluating the seat 3 from the seating running fatigue degree using the simulator have been described. For example, the specific seat 3 is left mounted, and a different pedestal 1 and vibration are maintained. It is also possible to evaluate the suspension system by interposing the modeled suspension system between the devices 4 and calculating the seating running fatigue level. When modeling the suspension system, it may be configured by hardware, or may be configured programmatically through mathematical modeling and incorporated in the vibration mode of the vibration device 4.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a vehicle seat evaluation simulator to which a seating traveling evaluation method and a vehicle seat evaluation method according to the present invention are applied. FIG. 2 is a perspective view showing a deflection sensor attached to a seat to be evaluated. Functional block diagram showing functions realized by the controller [Fig. 4] Flow chart showing a procedure for creating a fatigue evaluation formula [Fig. 5] Flow chart showing a procedure for evaluating a vehicle seat using a simulator [Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 Vehicle seat 4 Vibration apparatus 5 Controller 7 Acceleration sensor 8 Displacement sensor 51 Operation condition setting part 53 Sensor signal processing part 54 Seating running fatigue degree calculation part 55 Seat evaluation part

Claims (6)

A step of measuring a cushion characteristic generated in a vehicle seat when a human body is seated, a step of measuring a vibration characteristic of the human body and / or a seat in a vehicle running state, and a seated travel of the human body from the cushion characteristic and the vibration characteristic the fatigue Ri Do and a step of quantitatively determinable, said cushioning characteristics include the amount of deflection of the portion corresponding to the vicinity of the deflection amount and the body of thigh portions corresponding to the vicinity of the human body back, the seated traveling fatigue evaluation method that includes the lateral acceleration rate of change and the vertical acceleration of the seat of the human head in vibration characteristics. 2. The seating according to claim 1, wherein in the calculating step, an arithmetic expression determined by a statistical method is used from a fatigue level of the sitting running measured for a human body, the cushion characteristic, and the vibration characteristic. Driving fatigue evaluation method. The seating running fatigue degree according to claim 2, wherein the calculation formula is obtained by a multiple regression analysis using the cushion characteristic and the vibration characteristic as explanatory variables and the fatigue degree as an objective variable. Evaluation methods. The rate of change in lateral acceleration of the head of the human body is measured in the 2 to 4 Hz region, the vertical acceleration of the seat is measured in the 1 to 2 Hz region, and the fatigue level is based on the amount of change in adrenaline secretion before and after sitting on the human body. The seating running fatigue level evaluation method according to claim 2 or 3, characterized in that it is obtained by: A vehicle seat evaluation method for evaluating a used vehicle seat from the seating travel fatigue level calculated by the seating travel fatigue level evaluation method according to claim 1. A seating travel fatigue level evaluation formula obtained and incorporated in advance by the seating travel fatigue level evaluation method according to any one of claims 1 to 5,
A displacement sensor for measuring the amount of deflection of the portion corresponding to the vicinity of the back of the human body generated in the vehicle seat when the human body is seated and the amount of deflection of the portion corresponding to the vicinity of the thigh of the human body as cushion characteristics ;
A vibration device for bringing the vehicle seat into a vehicle running state;
An acceleration sensor for measuring the left right jerk and top and bottom acceleration of the seat of the human head in the vehicle running state as the vibration characteristics,
A calculation unit for calculating the degree of fatigue of seated running of the human body from the measured amount of both deflections, the rate of change in lateral acceleration, and the vertical acceleration , using the seated running fatigue evaluation formula ;
An evaluation unit for evaluating the vehicle seat from the calculation result of the calculation unit;
A vehicle seat evaluation simulator.

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