JPH0862083A - Inertia moment measuring instrument - Google Patents

Abstract

PURPOSE: To reduce time required for measurement in an inertial moment measuring instrument. CONSTITUTION: Left/right support links 30 are provided on a beam part 31B positioned at both left and right sides of a support stand 20. The left/right support link 30 rises while a middle part 30A is bent and moves to a gravity center height position when both edge parts 30B and 30C are moved by a specific amount in a direction where they approach each other. A forward/ backward support ring 40 is provided on a beam part located at the front and rear sides of the support stand 30 of the frame body 31. The forward/backward support link 40 rises while the middle part is bent and moves to the gravity center position when both edge parts are moved by a specific amount in a direction where they approach each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moment of inertia measuring device used for measuring a moment of inertia of an object to be measured such as a vehicle.

[0002]

2. Description of the Related Art Conventionally, examples of the inertial moment measuring device for measuring the inertial moment of an object to be measured such as an automobile include the Automotive Technology Handbook, Test / Evaluation, 5th.
Chapter Steering stability test (Issue date: June 1, 1991, first edition,
Issued by: Japan Automobile Technology Association).

As shown in FIG. 7, this inertial moment measuring device is provided with a measuring table 72 on which an object to be measured, for example, a vehicle body 70 is mounted. When measuring the inertial moment in the pitch direction, A rotary shaft 70A that penetrates 70 in the vehicle width direction is set. Further, as shown in FIG. 8, when measuring the moment of inertia in the roll direction, the vehicle body 7
A rotary shaft 70B that penetrates 0 in the vehicle front-rear direction is set.
Further, as shown in FIG. 9, when measuring the moment of inertia in the yaw direction, a rotary shaft 70C that penetrates the vehicle body 70 in the vehicle body vertical direction is set. These rotating shafts 70A, 7
The vehicle body 70 and the measuring table 72 are swung about 0B and 70C as shown by the imaginary lines in each figure, and each inertia moment is measured from the cycle.

Further, when measuring the vibration period, FIG.
As shown by 0, the measurement is not performed as the measurement waiting time T ₁ until the vibration cycle is stabilized, and the measurement of the vibration cycle is started after the measurement waiting time T ₁ .

[0005]

However, in this inertial moment measuring device, when the inertial moment in the roll direction is measured after the measurement of the inertial moment in the pitch direction is completed, the rotary shaft is rotated from the rotary shaft 70A. Axis 7
It is necessary to reset to 0B, and there is a problem that it takes time to measure. As an improved inertia moment measuring device, as shown in FIG. 11, the rotating shaft 74 is fixed, and the vehicle 76 is moved from the pitch moment of inertia moment measuring position 76A to the roll direction inertia moment measuring position 76B. There is a moving device. However, in the case of this device, although the measurement time can be shortened as compared with the one in which the rotation axis is set again, the setting position of the vehicle 76 is changed because manpower is required when setting the vehicle 76 on the measuring table 78. , There is a possibility that the measured values may vary.

Further, as shown in FIG. 10, when the vibration cycle is measured, the measurement wait time T ₁ is not measured until the vibration cycle stabilizes, which causes a problem that the measurement time becomes long.

In view of the above facts, an object of the present invention is to obtain an inertia moment measuring device capable of shortening the time required for measurement.

[0008]

According to the inertia moment measuring apparatus of the present invention as set forth in claim 1, the measuring table on which the object to be measured is placed and the measuring table is lifted and the rotation center is set when measuring the inertial moment in the pitch direction. And a first supporting member which is separated from the measuring table when the inertial moment is not measured, and a second supporting member which lifts the measuring table when measuring the inertial moment in the roll direction and sets a rotation center and is separated from the measuring table when the inertial moment is not measured. And a support member.

The inertial moment measuring device of the present invention as set forth in claim 2 predicts the point at which the amplitude is asymptotic from the relationship between the amplitude and the cycle of the measuring table at the time of measuring the inertial moment, and determines the vibration cycle based on this point. It is characterized by having a period calculation device.

[0010]

In the inertial moment measuring device according to the first aspect of the present invention, when measuring the inertial moment in the pitch direction, the first support member lifts the measuring table and sets the rotation center. Further, the first support member is separated from the measuring table when the inertial moment in the pitch direction is not measured. on the other hand,
When measuring the moment of inertia in the roll direction, the second support member lifts the measurement table and sets the rotation center. Further, the second supporting member is separated from the measuring table when the inertial moment in the roll direction is not measured. Therefore, the moment of inertia in the pitch direction and the moment of inertia in the roll direction can be measured without repositioning the measured object placed on the measuring table or the measuring table on which the measured object is arranged.

In the moment of inertia measuring device of the present invention as set forth in claim 2, the period calculating device predicts a point at which the amplitude is asymptotic from the relationship between the amplitude of the measuring table and the period at the time of measuring the moment of inertia, and based on this point. To determine the vibration cycle. For this reason, the waiting time becomes unnecessary as compared with the conventional technique in which measurement cannot be performed until the amplitude is stabilized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the moment of inertia measuring device of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the inertial moment measuring device 10 of the present embodiment is provided with a measuring table 16 for mounting a vehicle 12 and having a substantially rectangular shape in a plan view. It can be lifted up and down by a cylinder 17 for raising and lowering the measuring table, which is arranged below the measuring table 16 in the front, rear, left and right corners. An air bearing 18 is arranged on the measuring table 16 at a portion supporting each wheel 12A of the vehicle 12.
These air bearings 18 are used for adjusting the positions of the centers of gravity, and are for easily moving the vehicle 12 in a predetermined direction.

A support table 20 for supporting the measurement table 16 is disposed below the measurement table 16, and the load detector 2 constituting a vehicle center of gravity detector is provided at four corners of the lower surface of the measurement table 16.
4 are arranged respectively. These load detectors 24
When the measuring table 16 descends to the reference position, the projection 22 formed on the upper surface of the supporting table 20 comes into contact with the measuring table 16. Further, these load detectors 24 are
Amplifier 26 that constitutes a vehicle center of gravity detector and a cycle calculator
The personal computer 28 is connected to the personal computer 28 so that the operator can move the center of gravity of the vehicle 12 to the swing center while looking at the monitor 28A of the personal computer 28.

A frame 31 is arranged on the outer periphery of the support base 20. The frame 31 has leg portions 31A at four corners, and a pair of left and right support links 30 is arranged on the beam portions 31B located on both the left and right sides of the support base 20.
That is, the pair of left and right support links 30 are provided on both outer sides of the vehicle 12 in the vehicle width direction. The left and right support links 30 can be bent at the intermediate portion 30A, and the cylinder 32 provided on the beam portion 31B allows both end portions 30B and 30C to be bent.
Are moved toward and away from each other. Therefore, when both ends 30B and 30C are moved by the cylinder 32 in a direction approaching each other (direction of arrow A in FIG. 1) by a predetermined amount, the left and right support links 30 are lifted while the middle part 30A is bent, and will be described later. Method (vehicle 12
+ It moves to the position of the center of gravity of the measuring table 16).

In this state, the rotary shaft 34 disposed in the intermediate portion 30A of the left and right support links 30 and the measuring table 16 are connected to each other by a connecting member 36 having a triangular structure whose apex is fixed to the rotary shaft 34. . After that, when the cylinder 17 for raising and lowering the measuring table is lowered and separated from the measuring table 16, the measuring table 16
Can swing about the rotary shaft 34 as shown by the imaginary line in FIG.

As shown in FIG. 2, the support base 2 for the frame 31 is shown.
A pair of front and rear support links 40 are arranged on the beam portions 31C located on both front and rear sides of 0. That is, the pair of front and rear support links 40 are provided on both outer sides of the vehicle 12 in the front-rear direction of the vehicle body. The front-rear support link 40 has an intermediate portion 40A.
The cylinder 42 provided on the beam portion 31C moves the both end portions 40B and 40C in the direction in which they come into contact with and separate from each other. Therefore, when both ends 40B and 40C are moved by the cylinder 42 in a direction approaching each other (direction of arrow B in FIG. 1) by a predetermined amount, the front-rear support link 40 is lifted while the intermediate part 40A is bent, and will be described later. Method (vehicle 12 + measuring table 1
It is designed to move to the position of the center of gravity of 6).

In this state, the rotary shaft 44 arranged in the intermediate portion 40A of the front-rear support link 40 and the measuring table 16 are connected to each other by a connecting member 46 having a triangular structure whose apex is fixed to the rotary shaft 44. . After that, the rods 46 are connected to each other, and the cylinder 17 for raising and lowering the measuring table is lowered to be separated from the measuring table 16. The measuring table 16 can swing about the rotation axis 44 as shown by an imaginary line in FIG. Becomes

As shown in FIG. 3, the support base 20 has an upper portion 2
It has a two-layer structure of 0A and lower part 20B. Top 20
One end 50A of a cylinder 50 is swingably connected to the left and right sides of the rear end of A, and the other end 5A of the cylinder 50 is connected.
OB is swingably connected to the substrate 52. On the other hand, on the left and right sides of the front end of the upper portion 20A, one end 5 of the cylinder 54
4A is swingably connected, and the other end 54B of the cylinder 54 is swingably connected to the substrate 52. Therefore, when only the cylinder 50 is pressurized, the upper portion 20A rotates upward around the front end edge as the center of rotation as the rod of the cylinder 50 extends, and the state shown in FIG. 3 is obtained.

As shown in FIG. 4, the central portion of the support base is a rotary base 55, and the measuring base 16 and the vehicle 12 have the axis 55A of the rotary base 55 as the center of rotation in the left-right direction (see FIG. 4). It can be swung in the direction of arrow C).

As shown in FIG. 1, the measuring table 16 is provided with an acceleration sensor 60 for measuring the pitching and rolling periods, and an angle meter 61, and a rotary table 54.
Is provided with an angle meter 62 for measuring the yawing cycle. These acceleration sensor 60 and angle meter 6
1 and the goniometer 62 are connected to the personal computer 28 via the amplifier 26.
The data measured by the acceleration sensor 60, the angle meter 61 and the angle meter 62 are input to the personal computer 28.

Next, a measuring method by the inertia moment measuring device 10 of the present embodiment will be described. In step 1, the load detector 24 measures the mass Fp of the measuring table 16.
This measurement can be automatically performed by the operator operating the computer 28. Next, the vehicle 12 is manually placed on the measuring table 16. At this time, each wheel 12A of the vehicle 12 is placed on the air bearing 18. Next, the mass Ft of the vehicle 12 + measuring stand 16 is measured by the load detector 24, and the mass Fv of the vehicle 12 is measured from the result.
Note that this measurement can also be automatically performed by the operator operating the computer 28.

In step 2, the worker is the computer 2
Vehicle 12 + measuring platform 16 displayed on monitor 28A of 8
Of the vehicle 1 on the air bearing 18 so that the center of gravity Gv (x, y) of the vehicle coincides with the center of swing (the center of gravity of the measuring table 16).
2 is moved manually.

In step 3, the worker fixes the vehicle 12 to the measuring table 16. At this time, the vehicle height Hj at the front end of the rocker lower portion and the vehicle height Hk at the rear end of the rocker lower portion are set to the reference height by the jacks, and the lower portion of the rocker is clamped and fixed, and the body is fixed by the cloth belt.

In step 4, as shown in FIG. 3, only the cylinder 50 is pressurized to rotate the upper portion 20A of the support base 20 upward with the front edge portion as the center of rotation. In this state, the personal computer 28 is operated to measure the tilt angle θp of the measuring table 16 with the goniometer 61, the mass of the vehicle 12 + measuring table 16 is measured with the load detector 24, and the tilt is obtained from the result. The load change ΔF due to the above is calculated, and the vehicle 12 + measuring table 16 is calculated from the inclination angle θp and the load change ΔF.
The center of gravity height Ht _{1 of the} is calculated.

That is, when the center of gravity of the plane of the vehicle and the center of gravity of the apparatus are coincident with each other, the balance of moments around the center of rotation is as shown in FIG. Letting F1 be the reaction force of the load detector 24 facing the front part of the vehicle 12, and F2 the reaction force of the load detector 24 facing the rear part of the vehicle 12, (Ft × sin θ
_{p) × Ht 1 = (F1} -F2) × (L / 2) because becomes Ht ₁ = [(F1-F2) × (L / 2) ] / (Ft × si
nθp), and the height Ht ₁ of the center of gravity of the vehicle 12 + measuring table 16 can be measured.

Similarly, a measuring table 1 previously measured in advance
From the center of gravity height Ht _{2 of} 6, the center of gravity height Ht ₃ of the vehicle 12 is Ht ₃
= It can be calculated by Ht ₁ -Ht _2.

Further, when the center of gravity of the vehicle plane and the center of gravity of the apparatus plane are deviated from each other, as shown in FIG. 6, ΔX is the amount of deviation between the center of gravity of the vehicle plane and the center of gravity of the apparatus plane, as shown in FIG. Then, Ft × (sin θp × Ht ₁ × ΔX × cos θp) = (F
1−F2) × (L / 2), so Ht ₁ = [(F ₁ −F 2) × (L / 2) −Ft × ΔX × cos θp] / (Ft
× sin θp) ＝ [(F1-F2) × (L / 2)] / (Ft × sin θp
) −ΔX / tan θp, and the height Ht ₁ of the center of gravity of the vehicle 12 + measuring table 16 can be measured.

Similarly, a measuring table 1 previously measured in advance
From the center of gravity height Ht _{2 of} 6, the center of gravity height Ht ₃ of the vehicle 12 is Ht ₃
= It can be calculated by Ht ₁ -Ht _2.

The height of the center of gravity is calculated when only the cylinder 54 is pressurized and the upper portion 20A of the support base 20 is rotated upward with the rear edge as the center of rotation. The average value of the height of the center of gravity obtained by pressurizing only the center of gravity is defined as the height of the center of gravity. That is, since the average value is taken here, Δ
X can be canceled.

In step 5, the cylinder 1 for raising and lowering the measuring table is used.
7 is unlocked and the measuring table 16 is moved to a predetermined amount, for example 40
Raise it by 0 mm and lock the cylinder 17 for raising and lowering the measuring table again.

In step 6, as shown in FIG. 1, both ends 30 of the left and right support links 30 are moved by the cylinder 32.
B and 30C are moved in the direction of arrow A, and left and right support links 3
The rotary shaft 34 provided in the intermediate portion 30A of 0 is moved to the height of the center of gravity. At this time, the connecting member 3 fixed to the rotary shaft 34
Since 6 also rises, the connecting member 36 is fixed to the measuring table 16.

At step 7, the front and rear cylinders 17 for raising and lowering the measuring table give an initial inclination angle to the measuring table 16 to start free vibration. In this state, the free vibration period Tt of the vehicle 12 + measuring table 16, the vibration acceleration α, and the inertia moment Jy of the vehicle 12 in the pitch direction are obtained.

That is,

[0035]

[Number 1] _{Iv = (It-I p)} -m v h v 2 where, Iv: around the center of gravity of the inertia moment of the vehicle, It :( vehicle + rotation around the center of inertia of the measuring table), Ip: Measurements rotation around the center of the moment of inertia only platform, T _t free vibration period of :( vehicle + measuring table), Tp: free vibration period of the measurement table only, K: return spring constant, m _v: mass of the vehicle, m _p: The mass of the measurement table, h _v : the length between the center of rotation and the center of gravity of the vehicle, and h _p : the length between the center of rotation and the center of gravity of the measurement table.

Further, It is represented by Equation 2 and Ip is represented by Equation 3.

[0037]

## EQU2 ## It = (T _t / 2π) ² (K + m _v gh _v + m
_p gh _p )

[0038]

## EQU3 ## Ip = (Tp / 2π) ² (K + m _p gh _p ) Therefore, T _t and T _p are measured and corrected by the equations 2 and 3 to obtain I
Then, t and Ip are obtained, and the moment of inertia Iv about the center of gravity of the vehicle, in this case, the moment of inertia in the pitching direction is obtained from the equation (1).

After the measurement is completed, the brake is applied to stop the free vibration of the measuring table 16 and the tilt angle of the measuring table 16 is returned to 0 °. In this state, after the measuring table 16 is supported by the measuring table lifting cylinder 17, the connecting member 36 is separated from the measuring table 16, and the cylinder 32 is used to separate the both ends 30B, 30.
C is moved in the separating direction, and the rotary shaft 34 provided in the intermediate portion 30A of the left and right support links 30 is lowered. At this time, the connecting member 36 fixed to the rotating shaft 34 also descends.

In step 8, as shown in FIG. 2, both ends 40 of the front and rear support link 40 are moved by the cylinder 42.
B and 40C are moved in the direction of arrow B, and front and rear support links 4
The rotary shaft 44 provided in the intermediate portion 40A of 0 is moved to the gravity center height position Ht. At this time, since the connecting member 46 fixed to the rotary shaft 44 also rises, the connecting member 46 is moved to the measuring table 16
Fixed to.

In step 9, the left and right measuring table raising / lowering cylinders 17 give the measuring table 16 an initial inclination angle to start free vibration. In this state, the free vibration vibration period Tt of the vehicle 12 + measuring table 16, the vibration acceleration α, and the roll moment inertia moment Jx of the vehicle 12 are obtained.

After the measurement is completed, the brake is applied to stop the free vibration of the measuring table 16 and the tilt angle of the measuring table 16 is returned to 0 °. In this state, after the measuring table 16 is supported by the measuring table lifting cylinder 17, the connecting member 46 is separated from the measuring table 16, and both ends 40B, 40 are separated by the cylinder 42.
C is moved in the separating direction, and the rotary shaft 44 provided in the intermediate portion 40A of the left and right support links 40 is lowered. At this time, the connecting member 46 fixed to the rotating shaft 44 also descends.

In step 10, the cylinder 17 for lifting the measuring table is unlocked, the measuring table 16 is lowered to the reference position, and the cylinder 17 for raising and lowering the measuring table is locked again after the lowering.

In step 11, the moving means gives an initial tilt angle to the turntable 55 to start free vibration. As a result, the measuring table 16 starts free vibration. In this state, the vibration period Tt of the free vibration of the vehicle 12 + measuring table 16, the vibration acceleration α, and the moment of inertia Jz of the vehicle 12 in the yaw direction.
Ask for.

After the measurement is completed, the brake is applied to stop the free vibration of the measuring table 16 and the angle of the measuring table 16 is returned to 0 °.

In step 12, after the measuring table 16 is supported by the measuring table lifting cylinder 17, the position of the jig for fixing the vehicle 12 and the measuring table 16 is manually marked, and at the same time, the vehicle 12 is The fixation of the measuring table 16 is released, and the vehicle 12 is lowered from the measuring table 16.

In step 13, the vehicle 12 is manually operated.
The jig that fixed the measuring table 16 to the measuring table 16 is set at the marked position, and the load detector 24 is used to set the jig + measuring table 1
Measure the mass of 6.

In step 14, steps 4 to 11 are repeated with the vehicle 12 lowered.

Next, the operation of this embodiment will be described. In the moment of inertia measuring device 10 of the present embodiment, after the vehicle 12 is fixed on the measuring table 16 in the step 3, the vehicle 12 is fixed until the vehicle 12 is unloaded from the measuring table 16 in the step 12.
Does not need to be reset on the measurement table 16, so that the time required for resetting is eliminated and the measurement time is shortened, and the dispersion of the measurement values due to resetting the vehicle 12 on the measurement table 16 can be eliminated. it can. Further, as seen in the above-mentioned steps, since human intervention is eliminated as much as possible by automation, the error in artificial measurement can be reduced as compared with the conventional case.

Further, in the inertia moment measuring device 10 of this embodiment, when the vibration cycle is measured in the steps 7, 9 and 11, the amplitude θ in the damping state and the cycle T at that time are measured.
The data of 1 is taken into the personal computer 28, and is approximated to the formula 4 by the method of least squares.

[0051]

[Equation 4]

That is, assuming Equation 4, the logarithm of both sides of Equation 4 is taken as Equation 5.

[0053]

As Equation 5] logT = Bθ ^0.7 + logA, measured value T, the coefficient than theta A, Request B.

Further, Equation 5 is changed to Equation 6,

[0055]

Y = ax + b where y = logT, a = B, x = θ ^0.7 , b = lo
In gA, the equations 7 to 9 are obtained by the method of least squares.

[0056]

## EQU7 ## B = a = (Σx _i y _i −nxy) / (Σx _i ²
-Nx ² ) Here, x and y are average values and n is the number of data.

[0057]

## EQU00008 ## logA = b = y-ax

[0058]

## EQU9 ## A = e ^b = e ^{(y-ax) According to} Equations 7 to 9, the vibration cycle can be measured when the amplitude changes, that is, even in the measurement waiting time of the conventional technique. It should be noted that 0.7 in Expression 4 is a constant obtained by actual measurement from the known moment of inertia.

As described above, in the inertia moment measuring apparatus of the present embodiment, the personal computer 28 predicts a point at which the amplitude is asymptotic from the relationship between the amplitude θ and the cycle T, and obtains the vibration cycle based on this point. Therefore, the waiting time is unnecessary and the time required for measurement can be shortened as compared with the conventional technique in which measurement cannot be performed until the amplitude is stable.

Further, in the inertia moment measuring device of this embodiment, since the period measurement is performed while the decrease of the amplitude θ is small, the influence of the error due to the mechanical load of the device is small, and the measurement accuracy is improved as a result.

[0061]

According to the inertial moment measuring apparatus of the present invention as set forth in claim 1, the measuring table on which the object to be measured is placed and the measuring table is lifted when the inertial moment in the pitch direction is measured and the rotation center is set and the inertial moment is set. A first supporting member that is separated from the measuring table when not measuring, and a second supporting member that lifts the measuring table when measuring the moment of inertia in the roll direction, sets a rotation center, and separates from the measuring table when not measuring the moment of inertia; Since it is configured to have, there is an excellent effect that the time required for measurement can be shortened.

According to the inertia moment measuring apparatus of the present invention as defined in claim 2, the point at which the amplitude is asymptotic is predicted from the relationship between the amplitude and the cycle of the measuring table at the time of measuring the inertia moment, and the vibration cycle is obtained based on this point. Since the configuration has the period calculation device, it has an excellent effect that the time required for measurement can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a state when measuring an inertial moment in a pitch direction of an inertial moment measuring device according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing a state at the time of measuring the inertial moment in the roll direction of the inertial moment measuring device according to the embodiment of the present invention.

FIG. 3 is a schematic side view showing a state at the time of measuring the height of the center of gravity of the inertial moment measuring device according to the embodiment of the present invention.

FIG. 4 is a schematic plan view showing a state at the time of measuring the inertia moment in the yaw direction of the inertia moment measuring device according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of the measurement of the height of the center of gravity when the center of gravity of the vehicle plane and the center of gravity of the apparatus plane coincide with each other.

FIG. 6 is an explanatory diagram of the measurement of the height of the center of gravity when the center of gravity of the vehicle plane and the center of gravity of the apparatus are deviated.

FIG. 7 is a schematic side view showing a state at the time of measuring the inertial moment in the pitch direction of the inertial moment measuring device according to the conventional example.

FIG. 8 is a schematic front view showing a state at the time of measuring the inertial moment in the roll direction of the inertial moment measuring device according to the conventional example.

FIG. 9 is a schematic plan view showing a state at the time of measuring the inertial moment in the yaw direction of the inertial moment measuring device according to the conventional example.

FIG. 10 is a graph showing a relationship between period measurement time and amplitude according to a conventional example.

FIG. 11 is a schematic plan view of an inertial moment measuring device according to another conventional example.

[Explanation of symbols]

 10 Inertia Moment Measuring Device 12 Vehicle 16 Measuring Stand 17 Measuring Cylinder Lifting Cylinder 20 Supporting Stand 24 Load Detector (Vehicle Center of Gravity Detector) 26 Amplifier (Vehicle Center of Gravity Detector) 28 Personal Computer (Vehicle Center of Gravity Detector, Period Calculator) 30 Left and right support links 32 Cylinder 34 Rotation axis 40 Front-rear support link 42 Cylinder 44 Rotation axis 60 Accelerometer 61 Angle meter 62 Angle meter

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Iizuka, et al. 535 Sasai, Sayama City, Saitama Prefecture

Claims (2)

[Claims] 1. A measuring table on which an object to be measured is placed, and a first measuring table which lifts the measuring table when measuring a moment of inertia in the pitch direction, sets a rotation center, and separates from the measuring table when a moment of inertia in the pitch direction is not measured. Inertia, comprising: a support member; and a second support member that lifts the measurement table when measuring the inertial moment in the roll direction, sets a rotation center, and separates from the measurement table when the inertial moment in the roll direction is not measured. Moment measuring device. 2. The inertia moment is characterized by having a cycle calculator for predicting a point where the amplitude is asymptotic from the relationship between the amplitude of the measuring table and the cycle when measuring the inertia moment, and for obtaining the vibration cycle based on this point. Measuring device.