JP3142444B2 - Moment of inertia measurement device - Google Patents

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 apparatus used for measuring moment of inertia of an object to be measured such as a vehicle.

[0002]

2. Description of the Related Art Conventionally, in a moment of inertia measuring apparatus for measuring a moment of inertia of an object to be measured such as an automobile, an example thereof is an automobile technology handbook, Test and Evaluation, Vol.
Chapter Maneuvering Stability Test (Issued date: June 1, 1991 first edition,
Publisher: Japan Society of Automotive Engineers of Japan).

As shown in FIG. 7, the apparatus for measuring moment of inertia includes a measuring table 72 on which an object to be measured, for example, a vehicle body 70 is mounted. A rotating shaft 70A that penetrates 70 in the vehicle width direction is set. As shown in FIG. 8, when measuring the moment of inertia in the roll direction,
A rotation axis 70B is set to pass through 0 in the vehicle longitudinal direction.
As shown in FIG. 9, when measuring the moment of inertia in the yaw direction, a rotating shaft 70C that penetrates the vehicle body 70 in the vehicle vertical direction is set. These rotating shafts 70A, 7
The vehicle body 70 and the measuring table 72 are oscillated around the points 0B and 70C as indicated by imaginary lines in the respective drawings, and the respective inertia moments are measured from the cycle.

When measuring a vibration cycle, FIG.
As shown in 0, until the oscillation period is stabilized, without the measurement as a measurement waiting time T _1, and starts measuring the vibration period after the measurement the waiting time T _1.

[0005]

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

Further, as shown in FIG. 10, when the vibration cycle is measured, the measurement is not performed as the measurement waiting time T ₁ until the vibration cycle is stabilized.

An object of the present invention is to provide a moment of inertia measuring apparatus capable of reducing the time required for measurement in consideration of the above fact.

[0008]

According to a first aspect of the present invention, there is provided an apparatus for measuring moment of inertia, comprising: a measuring table on which an object to be measured is placed; A first support member that separates from the measuring table when the inertia moment is not measured, and a second supporting member that lifts the measuring table when measuring the inertia moment in the roll direction, sets the center of rotation, and separates from the measuring table when the inertial moment is not measured. And a supporting member.

According to a second aspect of the present invention, the moment of inertia measuring device predicts a point at which the amplitude approaches asymptotically from the relationship between the amplitude and the period of the measuring table at the moment of inertia measurement, and obtains a vibration period based on this point. It is characterized by having a period calculation device.

[0010]

In the inertial moment measuring apparatus 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 center of rotation. The first support member is separated from the measuring table when the moment of inertia 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 center of rotation. The second support member is separated from the measuring table when the inertia moment in the roll direction is not measured. Accordingly, the moment of inertia in the pitch direction and the moment of inertia in the roll direction can be measured without rearranging the object placed on the measuring table or the measuring table on which the measuring object is arranged.

In the inertia moment measuring apparatus according to the present invention, a point at which the amplitude asymptotically predicts from the relation between the amplitude and the period of the measuring table at the moment of inertia measurement by the period calculating device, and based on this point. To determine the oscillation period. For this reason, no waiting time is required as compared with the related art 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 apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, the apparatus for measuring moment of inertia 10 of the present embodiment includes a substantially rectangular measuring table 16 for mounting a vehicle 12 thereon. The measuring table 16 can be moved up and down by a measuring table elevating cylinder 17 disposed in the vicinity of four front, rear, left and right corners below the measuring table 16. The measurement table 16 is provided with an air bearing 18 at a position supporting each wheel 12A of the vehicle 12.
These air bearings 18 are used for adjusting the position of the center 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 a load detector 2 constituting a vehicle center-of-gravity detector is provided at four corners on the lower surface of the measurement table 16.
4 are provided respectively. These load detectors 24
When the measuring table 16 is lowered to the reference position, the protrusion 22 formed on the upper surface of the supporting table 20 comes into contact with the measuring table 16. In addition, these load detectors 24
Amplifier 26 constituting vehicle center of gravity detector and period calculation device
The operator moves the center of gravity of the vehicle 12 to the swing center while watching the monitor 28A of the personal computer 28.

A frame 31 is provided on the outer periphery of the support base 20. The frame 31 has legs 31A at four corners, and a pair of left and right support links 30 is disposed on a beam 31B located on both 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 in the vehicle width direction of the vehicle 12. The left and right support links 30 are bendable at an intermediate portion 30A, and are provided at both ends 30B and 30C by a cylinder 32 provided on a beam portion 31B.
Move in the direction of coming and going with each other. Therefore, when the both ends 30B and 30C are moved by the cylinder 32 by a predetermined amount in the direction (the direction of the arrow A in FIG. 1) approaching each other, the left and right support links 30 rise while the intermediate portion 30A is bent, and will be described later. (Vehicle 12
+ To the height of the center of gravity of the measuring table 16).

In this state, the rotating shaft 34 provided at the intermediate portion 30A of the left and right support link 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 rotating shaft 34. . Thereafter, the measuring table lifting cylinder 17 is lowered to be separated from the measuring table 16, and the measuring table 16
Is swingable about the rotation shaft 34 as shown by the imaginary line in FIG.

As shown in FIG. 2, the support 2 of the frame 31
A pair of front and rear support links 40 is disposed on the beam portions 31C located on both front and rear sides of the zero. That is, the pair of front and rear support links 40 are provided on both outer sides in the vehicle front and rear direction of the vehicle 12. The front and rear support link 40 is an intermediate portion 40A.
, And both ends 40B, 40C are moved in a direction in which the both ends 40B, 40C come into contact with and separate from each other by a cylinder 42 provided on the beam portion 31C. Accordingly, when both ends 40B and 40C are moved by a predetermined amount in the direction (arrow B direction in FIG. 1) approaching each other by the cylinder 42, the front and rear support link 40 rises while the intermediate portion 40A is bent, and will be described later. (Vehicle 12 + measuring table 1)
6) It moves to the position of the center of gravity.

In this state, the rotating shaft 44 provided at the intermediate portion 40A of the front and rear support link 40 and the measuring table 16 are connected to each other by a connecting member 46 having a triangular structure whose top is fixed to the rotating shaft 44. . Thereafter, the measuring table 16 is connected with the rod 46, and the measuring table elevating cylinder 17 is lowered to be separated from the measuring table 16, so that the measuring table 16 can swing about the rotary shaft 44 as shown by the imaginary line in FIG. Becomes

As shown in FIG. 3, the support 20 is
It has a two-layer structure of 0A and lower part 20B. Upper 20
One end 50A of a cylinder 50 is swingably connected to both left and right sides of the rear end of the cylinder A.
OB is swingably connected to the substrate 52. On the other hand, one end 5 of the cylinder 54 is provided on the left and right sides of the front end of the upper portion 20A.
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 about the front end edge as the rod of the cylinder 50 extends, and the state shown in FIG. 3 is obtained.

As shown in FIG. 4, the center of the support table is a rotary table 55, and the measuring table 16 and the vehicle 12 move in the left-right direction with the axis 55A of the rotary table 55 as the center of rotation (FIG. 4). (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 a goniometer 61.
Is provided with a goniometer 62 for measuring the yaw cycle. These acceleration sensor 60 and goniometer 6
1 and the angle meter 62 are connected to the personal computer 28 via the amplifier 26.
The data measured by the acceleration sensor 60, the goniometer 61, and the goniometer 62 are input to the personal computer 28.

Next, a measuring method using the moment of inertia measuring device 10 of the present embodiment will be described. In step 1, the mass Fp of the measuring table 16 is measured by the load detector 24.
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 put on the air bearing 18. Next, the mass Ft of the vehicle 12 + the measuring table 16 is measured by the load detector 24, and the mass Fv of the vehicle 12 is measured from the result.
This measurement can also be performed automatically by the operator operating the computer 28.

In step 2, the operator operates the computer 2
8 and the measuring stand 16 displayed on the monitor 28A of No. 8
Of the vehicle 1 on the air bearing 18 so that the center of gravity Gv (x, y) of the vehicle 1 coincides with the swing center (the center of gravity of the measuring table 16).
2 is moved manually.

In step 3, the operator fixes the vehicle 12 to the measuring table 16. At this time, the vehicle height Hj at the front end of the lower rocker and the vehicle height Hk at the rear end of the lower rocker are set to reference heights by the jacks, and the lower part 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, and the upper part 20A of the support base 20 is rotated upward about the front edge. In this state, the personal computer 28 was operated to measure the inclination angle θp of the measuring table 16 by the goniometer 61, and the mass of the vehicle 12 + the measuring table 16 was measured by the load detector 24. And the load change ΔF are calculated from the inclination angle θp and the load change ΔF.
Calculating the center of gravity height Ht _1.

That is, when the center of gravity of the vehicle and the center of gravity of the apparatus coincide with each other, the balance of the moment around the rotation center is represented by L / 2 from the center line to the load detector 24 as shown in FIG. If the distance and F1 are the reaction force of the load detector 24 facing the front part of the vehicle 12 and F2 is 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) Ht ₁ = [(F1−F2) × (L / 2)] / (Ft × si
nθp), and the height Ht ₁ of the center of gravity of the vehicle 12 and the measuring stand 16 can be measured.

The measuring table 1 previously measured in the same manner
The center of gravity from the height Ht ₂ of 6, the center of gravity height Ht ₃ of the vehicle 12 Ht ₃
= It can be calculated by Ht ₁ -Ht _2.

When the center of gravity of the vehicle is shifted from the center of gravity of the apparatus, the balance of the moment about the rotation center is represented by ΔX, as shown in FIG. Then, Ft × (sin θp × Ht ₁ × ΔX × cos θp) = (F
1−F2) × (L / 2) Ht ₁ = [(F1−F2) × (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 and the measuring stand 16 can be measured.

The measuring table 1 previously measured in the same manner
The center of gravity from the height Ht ₂ of 6, the center of gravity height Ht ₃ of the vehicle 12 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 part 20A of the support base 20 is rotated upward with the rear edge as the center of rotation, and the height of the center of gravity and the height of the cylinder 50 are calculated. The average value of the height of the center of gravity and the height of the center of gravity alone is defined as the height of the center of gravity. That is, to take the average value here, Δ
X can be canceled.

In step 5, the measuring table lifting cylinder 1
7 is unlocked, and the measuring table 16 is set to a predetermined amount, for example, 40
Then, the measuring table elevating cylinder 17 is locked again.

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

In step 7, the initial tilt angle is given to the measuring table 16 by the front and rear measuring table lifting cylinders 17 to start free vibration. In this state, the free vibration period Tt, the vibration acceleration α, and the moment of inertia Jy of the vehicle 12 in the pitch direction of the vehicle 12 and the measuring stand 16 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: measurement table of mass, h _v: length between the rotational center and the center of gravity of the vehicle, h _p: a length, between the rotation center and the measuring table centroid.

In addition, It is represented by Expression 2 and Ip is represented by Expression 3.

[0037]

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

[0038]

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

After the measurement is completed, the brake is applied to stop the free vibration of the measuring table 16, and the inclination angle of the measuring table 16 is returned to 0 °. In this state, after the measuring table 16 is supported by the measuring table elevating cylinder 17, the connecting member 36 is separated from the measuring table 16, and the both ends 30 B, 30
C is moved in the separating direction, and the rotating shaft 34 provided at the intermediate portion 30A of the left and right support link 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.
B and 40C are moved in the direction of arrow B,
The rotation shaft 44 provided in the intermediate portion 40A of the zero is moved to the center of gravity height position Ht. At this time, the connecting member 46 fixed to the rotating shaft 44 also rises, so that the connecting member 46 is
Fixed to.

In step 9, the initial tilt angle is given to the measuring table 16 by the right and left measuring table lifting cylinders 17 to start free vibration. In this state, the free vibration period Tt, the vibration acceleration α, and the moment of inertia Jx of the vehicle 12 in the roll direction are obtained.

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

In step 10, the lock of the measuring table elevating cylinder 17 is released, the measuring table 16 is lowered to the reference position, and after the descent, the measuring table elevating cylinder 17 is locked again.

In step 11, an initial inclination angle is given to the turntable 55 by the moving means to start free vibration. As a result, the measuring table 16 starts free vibration. In this state, the free vibration vibration period Tt, the vibration acceleration α of the vehicle 12 + the measuring stand 16 and the inertia moment Jz of the vehicle 12 in the yaw direction are obtained.
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, the measuring table 16 is supported by the measuring table elevating cylinder 17, and the position of the jig fixing the vehicle 12 and the measuring table 16 is manually marked. The fixing to 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 which fixed the measuring table 16 and the measuring table 16 is set at the marked position, and the load detector 24 sets the jig + the 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 apparatus 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 lowered from the measuring table 16 in the step 12.
Since it is not necessary to reset the vehicle 12 on the measurement table 16, the time required for the resetting is eliminated and the measurement time is shortened, and the dispersion of the measurement values due to the resetting of the vehicle 12 on the measurement table 16 is eliminated. it can. Further, as seen in the above steps, human intervention is eliminated as much as possible by automation, so that an artificial measurement error can be reduced as compared with the related art.

In the moment of inertia measuring apparatus 10 of this embodiment, when measuring the vibration period in the steps 7, 9, and 11, the amplitude θ in the damped state and the period T
Is taken into the personal computer 28, and approximated by the least squares method to Equation 4.

[0051]

(Equation 4)

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

[0053]

## EQU5 ## As logT = Bθ ^0.7 + logA, coefficients A and B are obtained from the measured values T and θ.

Equation 5 is replaced by Equation 6,

[0055]

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

[0056]

Equation 7] _{B = a = (Σx i y} i -nxy) / (Σx i 2
−nx ² ) where x and y are average values, and n is the number of data.

[0057]

## EQU8 ## logA = b = y-ax

[0058]

A = e ^b = e ^{(y-ax) According to} Equations 7 to 9, the vibration cycle can be measured even when the amplitude is changing, that is, even in the measurement waiting time of the prior art. Note that 0.7 in Equation 4 is a constant obtained by actually measuring from a known moment of inertia.

As described above, in the moment of inertia measuring apparatus according to the present embodiment, the personal computer 28 predicts a point at which the amplitude approaches asymptotically from the relationship between the amplitude θ and the cycle T, and obtains the oscillation period based on this point. Therefore, as compared with the related art in which measurement cannot be performed until the amplitude is stabilized, a waiting time is not required, and the time required for measurement can be reduced.

In the moment of inertia measuring apparatus according to the present embodiment, the period is measured while the amplitude θ is small, so that the influence of an error due to the mechanical load on the apparatus is small, and as a result, the measuring accuracy is improved.

[0061]

According to a first aspect of the present invention, there is provided an apparatus for measuring moment of inertia, comprising: a measuring table on which an object to be measured is placed; lifting the measuring table when measuring the moment of inertia in the pitch direction; A first support member that is separated from the measurement table during non-measurement, a second support member that sets the rotation center while lifting the measurement table when measuring the inertia moment in the roll direction and separates from the measurement table when inertia moment is not measured, Has an excellent effect that the time required for measurement can be reduced.

According to a second aspect of the present invention, the moment of inertia measuring device predicts a point at which the amplitude approaches asymptotically from the relationship between the amplitude and the period of the measuring table at the moment of inertia measurement, and obtains the vibration period based on this point. The configuration having the period calculation device has an excellent effect that the time required for measurement can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a state of a moment of inertia measurement in a pitch direction of a moment of inertia measuring apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic front view showing a state when measuring the inertia moment in the roll direction of the inertia moment measurement device according to one embodiment of the present invention.

FIG. 3 is a schematic side view showing a state when measuring the height of the center of gravity of the moment of inertia measuring apparatus according to one embodiment of the present invention.

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

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

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

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

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

FIG. 9 is a schematic plan view showing a state in which a moment of inertia in a yaw direction is measured by a moment of inertia measuring apparatus according to a conventional example.

FIG. 10 is a graph showing a relationship between a cycle measurement time and an 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]

 DESCRIPTION OF SYMBOLS 10 Moment of inertia measuring device 12 Vehicle 16 Measuring table 17 Cylinder for elevating and lowering measuring table 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 arithmetic unit) 30 Left and right support link 32 Cylinder 34 Rotation axis 40 Front and back support link 42 Cylinder 44 Rotation axis 60 Accelerometer 61 Angle meter 62 Angle meter

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Iizuka et al. 535 Sasai, Sayama-shi, Saitama (56) References German Patent Application Publication 2717454 (DE, A1) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G01M 1/10

Claims (2)

(57) [Claims] 1. A measuring table on which an object to be measured is placed, and a first table which lifts the measuring table when measuring the moment of inertia in the pitch direction, sets the center of rotation, and separates from the measuring table when the moment of inertia in the pitch direction is not measured. An inertia comprising: a support member; and a second support member that lifts the measurement table when measuring the inertia moment in the roll direction, sets the center of rotation, and separates from the measurement table when the inertia moment in the roll direction is not measured. Moment measuring device. 2. A moment of inertia comprising a period calculating device for predicting a point at which the amplitude approaches asymptotically from the relationship between the amplitude and the period of the measuring table at the moment of inertia measurement and obtaining a vibration period based on this point. Measuring device.