JPH09178516A - Posture stability evaluation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small system for evaluating the stability of specific posture quantitatively by a convenient method. SOLUTION: A traveling base section mounting a subject is moved under specified conditions to load the subject with an acceleration and a limit acceleration for sustaining balance of the subject is determined. Stability of posture is then evaluated quantitatively from the duration characteristics of limit acceleration. Limit acceleration for long duration is determined from the limit acceleration characteristics for short duration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a posture stability evaluation device for evaluating posture stability of a body.

[0002]

2. Description of the Related Art Generally, in order to examine the stability of a human standing upright posture, a center of gravity sway meter (JIS T 1190) is widely used in ophthalmology,
It is used in the fields of neurology, otolaryngology, rehabilitation engineering, sports engineering and the like. This inspection method using a body sway meter puts the subject (patient) on the body sway meter installed on the floor surface, imports the displacement amounts in the X-axis and Y-axis directions in the floor surface into a computer, The frequency spectrum distribution of the distance of movement of the center of gravity and the amount of displacement is calculated, and the function of maintaining the upright posture is evaluated from the results.

[0003] However, the body sway characteristic values (the center of gravity sway distance, the area of sway of the center of gravity, the spectrum value by frequency, etc.) obtained from the body sway meter are, for example, qualitatively Because it is used for relative comparison, how the measured value is specifically related to the function of maintaining the upright posture, how much the measured value affects actual life situations, falls, etc. It is not enough to explain if there is danger.

[0004] As another supplementary posture stability evaluation method, it is intended to quantitatively evaluate the stability of the upright posture by using an electromyogram, an energy metabolism, a sole pressure distribution map and the like. Attempts have been made, but have not solved the aforementioned basic problems of the sway meter. Therefore, the acceleration stimulus of the step-like acceleration pattern generated assuming an unexpected stimulus using a linear accelerator that can apply a step-like acceleration stimulus to the subject by controlling the servomotor with a computer is used. 2. Description of the Related Art There is known a posture stability evaluation device that loads a subject and evaluates the stability of the posture based on a limit acceleration at which the subject can maintain balance.

[0005]

However, in the conventional posture stability evaluation apparatus using such a linear accelerator, in order to enable measurement even when the acceleration duration is long, As shown in FIG. 9, the total length of the linear accelerator is about 11 m. Therefore, the installation of the posture stability evaluation device requires a large space, and the manufacturing cost of the device is high, which is not practical.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a posture stability evaluation apparatus capable of simply and quantitatively evaluating the posture stability while reducing the size of the apparatus. .

[0007]

According to one aspect of the present invention, there is provided a posture stability evaluation apparatus for evaluating stability in a specific posture, wherein an acceleration stimulus is applied to a subject. In this way, the stability of the posture was evaluated from the relationship between the acceleration and the duration that could maintain the balance of the subject.

According to a second aspect of the present invention, in the posture stability evaluation device, the running stability is such that a running platform on which a subject is mounted and travels at an equal acceleration, control means for controlling acceleration applied to the running platform, Evaluation means for evaluating the stability of the posture from the relationship between the limit acceleration and the duration of the acceleration. According to a third aspect of the present invention, the control means controls the acceleration level to be changed while keeping the duration constant.
The evaluation means obtains a limit acceleration capable of maintaining the balance of the subject, and evaluates the stability of the posture from the relationship between the limit acceleration and the holding time.

According to a fourth aspect of the present invention, the control means can generate an acceleration stimulus having an arbitrary waveform. In the invention described in claim 5, the control means includes a ball screw rotatable by a motor, and a ball screw nut engaged with the ball screw and fixed to the traveling platform.

[0010] With this configuration, the ball screw nut moves with the rotation of the ball screw, and the traveling platform to which the ball screw nut is fixed moves.
According to a sixth aspect of the present invention, the control means includes a pulley that is driven to rotate by a motor, and a timing belt that is suspended from the pulley and whose end is fixed to the traveling platform.

[0011] With this configuration, the timing belt moves with the rotation of the pulley, and the traveling platform to which the timing belt is fixed moves. In the invention described in claim 7, the specific posture is an upright standing posture. In the invention described in claim 8, the traveling platform has a floor portion whose rotation position can be changed so that the direction of the subject can be changed in a traveling plane on which the subject is placed.

[0012]

According to the first aspect of the present invention, the stability in a specific posture can be quantitatively evaluated from the relationship between the acceleration and the duration of the acceleration. Sex can be evaluated. According to the invention as set forth in claim 2, a subject in a specific posture placed on the traveling platform is loaded with acceleration by moving the traveling platform, and the acceleration applied to the subject and the acceleration Since the relationship with the duration can be obtained, the stability of a specific posture can be more easily evaluated.

According to the third aspect of the present invention, the posture stability is evaluated based on the limit acceleration capable of maintaining the balance of the subject, so that the evaluation can be performed with high accuracy, and the limit acceleration for a long duration is obtained. , Can be inferred from the characteristics of marginal acceleration for short durations, eliminating the need for measurements for long durations,
Thus, the moving distance of the traveling platform can be reduced, and the size of the posture stability evaluation device can be reduced.

According to the fourth aspect of the invention, by generating an arbitrary waveform such as a step wave, a sine wave, a triangular wave or the like, the stability of the posture with respect to the acceleration stimulus by each waveform can be easily evaluated. be able to. According to the fifth aspect of the present invention, the traveling platform can be moved more stably and more accurately, and the responsiveness of control to the movement of the traveling platform can be improved.

According to the sixth aspect of the present invention, the traveling platform can be stably moved with an inexpensive configuration, the noise during movement can be further reduced, and maintenance can be facilitated. . According to the invention described in claim 7, it is possible to evaluate the stability of the subject in the upright standing posture.

According to the eighth aspect of the present invention, by performing the experiment in which the subject is oriented in any direction within the traveling plane, the acceleration can be applied in any direction of the subject. The stability of the posture with respect to the direction can be evaluated.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. First, FIG. 1 shows a basic block configuration of the posture stability evaluation device for the upright posture in the first embodiment. The test machine main body 11 is provided with a traveling platform 12 that applies an acceleration stimulus to the subject by placing and moving the subject, and a driving unit 13 that generates a driving force for moving the traveling platform 12 and transmits the driving force to the traveling platform. Is composed of
Further, an acceleration detection unit 14 for detecting acceleration applied when the traveling platform 12 moves, and a driving unit 13 through an interface 15
And a control unit 16 for controlling the control via.

Next, a specific configuration of each component will be described. First, FIG. 2 shows a front view of the posture stability evaluation apparatus, FIG. 3 shows a side view of the test machine main body, and FIG. 4 shows a plan view of the test machine main body. In this tester main body, two rails 22 are laid in parallel with the longitudinal direction of the base 21 on the upper surface of the base 21 of the tester main body installed on the floor surface.
Posted via 24.

On the other hand, a drive motor 25 is provided at one end of the base 21 as a power source for moving the traveling platform, and a ball screw 26 is connected to a shaft of the drive motor 25 via a shaft joint 27. This ball screw 26 is engaged with a ball screw nut in a bearing portion 28 fixed to the traveling base portion 23 side, and a driving motor
By controlling the rotation of 25, the reciprocating motion of the traveling platform 23 can be controlled.

At both ends of the rail 22, limit switches 29a and 29b for stopping the movement of the traveling platform 23 are provided to prevent the traveling platform from being derailed. Next, a specific configuration of the traveling platform 23 will be described. A handrail 30 is installed on the traveling platform 23 so as to surround the subject 31, and when the subject 31 is about to collapse due to the stimulus associated with the movement of the traveling platform 23, the body 30 is placed over the entire circumference of the handrail 30. A shock absorbing pad 32 for receiving is attached.

The traveling platform 23 allows the subject 31 to be loaded with an acceleration stimulus from an arbitrary direction.
As shown in the figure, a rotatable circular floor 33 on which the subject 31 is placed is provided at the center of the traveling platform 23. This circular floor 33
By turning the handle 35 connected to the worm gear 34, the subject 31 can be directed in an arbitrary direction within the rotation plane of the circular floor 33. Further, the circular floor 33 is fixed so as not to move while the traveling platform 23 is moving.

On the other hand, an opening 36 that can be opened and closed is provided on a side surface of the traveling platform 23, and the traveling platform 23 of the subject 31 is provided.
It facilitates ingress and egress, and an acceleration sensor (not shown) is provided on the traveling platform 23 to measure the acceleration applied to the subject 31 when the traveling platform is moved. . The drive motor 25 moves the traveling platform 23 (1.2 m).
Within the range of, the control unit 37 having a performance capable of rapidly accelerating to at least 2 m / s and including a programmable computer connected via a control interface 37
The drive is controlled by

Next, the basic structure of the controller 37 will be described. FIG. 5 shows a block diagram for controlling the drive motor. First, an acceleration stimulus signal having an arbitrary waveform is generated by the CPU 51, and the acceleration stimulus signal is
The signal is converted into a signal for driving the motor by the motor driver 53 via the / A converter. Then, by inputting the motor drive signal to the drive motor 54, the drive motor
Rotate 54 to move the carriage under predetermined conditions.

The acceleration stimulus signal is, for example, a step wave,
By using a regular waveform such as a sine wave or a triangular wave, it is possible to more easily evaluate the posture stability. On the other hand, the tachogenerator 55 detects the rotation speed of the drive motor 54 and feeds it back to the motor driver 53 so that the rotation control of the drive motor 54 can be performed more accurately. ,speed,
By detecting the acceleration from the drive motor and feeding it back to the CPU 51 via the A / D converter of the interface 52, the CPU 51 can perform arithmetic processing on control conditions and the like.

A specific configuration of the control unit 37 includes, for example, a programmable computer such as a personal computer, and a monitor, an input device, a printing machine, and the like connected to the computer. By using such a computer, the aforementioned acceleration stimulus signal can be generated by software, and the acceleration stimulus signal can be output through an interface. In addition, the control status and the like can be confirmed on a monitor connected to the computer, It is possible to input and set conditions and the like, and output information on a loaded stimulus and the like by a printing machine as needed.

It is desirable that the computer can perform position control, speed control, and the like at step intervals of 10 msec or less, and may be configured to generate an acceleration stimulus signal by hardware. A method for evaluating the stability of the subject in the upright standing posture using the posture stability evaluation device described above will be described.

As an outline of the method for evaluating the posture stability, a subject placed on a traveling platform is allowed to take an upright standing posture, and a momentary horizontal acceleration stimulus is applied for a certain period of time until the balance of the upright standing posture is lost. By applying the load, the relationship between the acceleration stimulus (limit acceleration), which is the limit of maintaining the upright posture, and the time during which the acceleration stimulus was loaded (duration) is evaluated, and the stability of the posture is evaluated from this relationship. Is what you do.

First, the basic theory for the posture stability evaluation method will be described below. FIG. 6 shows the change in the limit acceleration α with respect to the reciprocal of the duration t. As shown in FIG. 6, the limit acceleration α changes in proportion to the reciprocal of the duration t. Therefore, the limit acceleration α can be expressed by equation (1). Equation (2) is a result of modifying equation (1), and α _c represents α-b. α = a · (1 / t ) + b ··· (1) α c · t = a ··· (2) here, a subjects (healthy people and people with disabilities, young and elderly, men and women Etc.) and corresponds to the slope of the straight line in FIG. In addition, b is a constant determined by upright standing conditions (footwear or the like), and represents an intercept of the limit acceleration value α axis in FIG.

When the conditions of the expressions (3) and (4) are simultaneously satisfied, the holding limit of the upright posture is reached. α ≧ b (3) α _c · t ≧ a (4) Here, α _c · t represents a speed. Also, α
Under the condition of <b, the upright posture can be maintained even when the duration is long.

That is, the factor affecting the upright standing posture is the acceleration α _c of a constant b or more among the limit acceleration α that is the acceleration stimulus of the step wave shown in FIG. 7, and the speed caused by the acceleration α _c When the increment α _c · t becomes equal to or larger than the constant a, the balance of the upright posture is lost. Next, a specific method of evaluating the stability of the posture using this basic theory will be described. Here, an acceleration stimulus of a step wave is applied to the subject so as to be a uniform acceleration stimulus.

The control unit generates an acceleration stimulus signal of a predetermined acceleration level with a constant duration,
The drive motor is rotated based on the acceleration stimulus signal, and a predetermined acceleration is applied to the subject on the traveling platform. This acceleration load operation is repeatedly performed while gradually increasing the acceleration level until the subject loses balance. Then, a limit acceleration at which the subject loses balance is detected by the acceleration sensor, and this acceleration is set as a limit acceleration.

In the above procedure, the limit acceleration is measured for each holding time, and the change characteristics between the limit acceleration and the reciprocal of the duration, that is, the constants a and b are linearly approximated by, for example, the least square method. Ask by The stability of the upright posture can be evaluated based on the change characteristics (constants a and b) between the limit acceleration and the reciprocal of the duration thus obtained.

Since the change characteristic of the limit acceleration with respect to the reciprocal of the duration is almost linear, it is sufficient to measure the limit acceleration for a short duration.
The limit acceleration for a long duration may be estimated using the change characteristics (constants a and b) as needed. As a result, the stability of the upright posture can be evaluated without measuring the limit acceleration for a long duration, so that a long traveling distance is not required, and the traveling distance of the traveling platform can be shortened. Therefore, the posture stability evaluation device can be made more compact. This eliminates the need for a particularly large space at the installation location of the posture stability evaluation device, and in this embodiment, reduces the traveling distance of the traveling platform to about 1.2 m.

Further, since the limit acceleration when the acceleration stimulus such as a sine wave is loaded can be estimated to some extent on the basis of the characteristic of the limit acceleration by the acceleration stimulus of the uniform acceleration,
It is possible to evaluate the posture stability to some extent even with an acceleration stimulus such as a sine wave. As described above, in the present embodiment, unlike the posture stability evaluation device using the body sway characteristic values (the body sway area and the body sway distance) which are widely used, the limit acceleration at which the user loses balance and falls down is evaluated. Because it is used as an index, it is possible to quantitatively evaluate how foot position, heel height, handrail effect, age difference, gender difference, etc., affect the stability of upright standing posture, and can be widely applied. be able to.

For example, when setting the operating speed of a train or the like,
Or determined acceleration limit from the value or the like of the aforementioned acceleration alpha _c,
By obtaining the limit speed from the b value, these values can be used as design data. Also, in the rehabilitation training of a disabled person, it is possible to simulate the actual life and to examine whether the disabled person can cope with acceleration or deceleration in a bus or a train, for example.

Since the posture stability evaluation device can be made compact, the manufacturing cost and installation area of the device can be significantly reduced, and the practicality can be improved. Next, a description will be given of a second embodiment in which the traveling platform is moved using a timing belt. FIG.
FIG. 3 is a configuration diagram schematically illustrating a moving mechanism of a traveling platform in the present embodiment.

That is, the ends 84a and 84b of the timing belt 84 are fixed to the traveling platform 83 mounted on the upper surface of the base 81 via the wheels 82a and 82b, respectively, and are disposed at both ends of the base 81. While the timing belt 84 is suspended on the pulleys 85a and 85b, the drive motor 86 is disposed on one pulley 85a side, and the shaft of the motor 86 is connected to the shaft of the pulley 85a via a gear 87. By driving the timing belt, the traveling platform 83 can be moved.

By using such a timing belt to move the traveling platform, it is possible to reduce the trouble of maintenance and noise during traveling, to obtain an effect of easy adjustment, and to achieve a simple structure. Since it is inexpensive, manufacturing costs can be reduced. The posture stability evaluation device described above can also be applied to posture research in other fields such as otolaryngology, neuroscience, and health and physical education.

[Brief description of the drawings]

FIG. 1 is a basic block configuration diagram of a posture stability evaluation device.

FIG. 2 is a front view of the posture stability evaluation device according to the first embodiment.

FIG. 3 is a side view of the tester main body according to the first embodiment.

FIG. 4 is a plan view of a tester main body according to the first embodiment.

FIG. 5 is a control block diagram of a control unit.

FIG. 6 is a diagram illustrating a change in a limit acceleration with respect to a reciprocal value of a duration.

Figure 7 illustrates a relationship between the load acceleration alpha and constants b and alpha _c.

FIG. 8 is a schematic configuration diagram illustrating a moving mechanism of a traveling platform according to a second embodiment.

FIG. 9 shows a posture stability evaluation device using a conventional linear accelerator.

[Explanation of symbols]

 11 Test machine body 12 Carriage platform 13 Drive unit 14 Acceleration detector 16 Control unit 25 Drive motor 26 Ball screw 31 Subject 33 Circular floor 34 Worm gear 84 Timing belt

Claims (8)

[Claims] 1. A posture stability evaluation device for evaluating stability in a specific posture, wherein the posture is evaluated based on a relationship between a limit acceleration capable of maintaining a balance of the subject and a duration by applying an acceleration stimulus to the subject. A posture stability evaluation device that evaluates the stability of a vehicle. 2. The posture stability evaluation device, comprising: a traveling platform on which a subject is mounted and traveling at an equal acceleration; control means for controlling an acceleration applied to the traveling platform; An evaluation means for evaluating posture stability from a relationship with a duration. 3. The control means controls the acceleration level to be changed while keeping the duration constant, and the evaluation means obtains a limit acceleration capable of maintaining the balance of the subject, and calculates the limit acceleration and the holding time. The posture stability evaluation device according to claim 1 or 2, wherein the posture stability is evaluated from the relationship. 4. The control device according to claim 1, wherein said control means is capable of generating an acceleration stimulus having an arbitrary waveform.
The posture stability evaluation device according to any one of the first to third aspects. 5. The control device according to claim 1, wherein the control means includes a ball screw rotatable by a motor, and a ball screw nut engaged with the ball screw and fixed to the traveling platform. The posture stability evaluation device according to any one of the first to third aspects. 6. The control means includes a pulley that is driven to rotate by a motor, and a timing belt suspended by the pulley and having an end fixed to the traveling platform.
The posture stability evaluation device according to claim 1. 7. The posture stability evaluation device according to claim 1, wherein the specific posture is an upright posture. 8. The vehicle according to claim 1, wherein the traveling platform has a floor portion whose rotation position can be changed so that the direction of the subject can be changed in a traveling plane on which the subject is placed. The posture stability evaluation device according to any one of the above.