JP3524799B2 - Centrifugal loading 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 centrifugal loading device, and more particularly to a centrifugal loading device for adjusting a centrifugal center of gravity.

[0002]

BACKGROUND OF THE INVENTION Large structures such as buildings are built on the ground. Prior to construction, the physical properties of the ground need to be known. A 1 / N scale model is produced and given N times the acceleration of gravity. Such acceleration is given as centrifugal acceleration. A centrifugal loading device is used as a device that provides centrifugal acceleration. Trial-and-error adjustment of the balance around the axis of rotation of the rotating part of a centrifugal loading device is a very cumbersome task.

A device for automatically adjusting such a balance is known. Japanese Patent No. 2568007 discloses a technique capable of adjusting a centrifugal balance by moving two moving objects moving on two parallel straight lines on a rotary table. In such a technique, the centrifugal adjustment can be performed on a fixed position straight line without stopping the rotation of the rotary table, but the known technique for performing the centrifugal adjustment based on the relative movement of two moving objects on two parallel parallel lines. Is insufficient in the degree of freedom necessary for balancing and moving the centrifuge point to an arbitrary position on the two-dimensional plane to perform centrifugal adjustment. High-precision centrifugal control by movement is impossible. High-precision centrifugal control is desired by moving a centrifugal point on a two-dimensional surface that is a rotating surface.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a centrifugal loading device capable of performing centrifugal control with higher accuracy. Another object of the present invention is to provide a centrifugal loading device that can perform centrifugal control with higher accuracy by moving an adjustment centrifugal point to an arbitrary position on a two-dimensional surface that is a rotating surface. is there. Still another object of the present invention is to provide a centrifugal loading device in which physical calculation for two-dimensional centrifugal control is rational. Another object of the present invention is to centrifuge which can perform centrifuge control with higher precision and with a simple mechanism by moving the adjusting centrifuge point to an arbitrary position on the two-dimensional surface which is the rotation surface. To provide a loading device.

[0005]

Numbers with () appearing in the following description in which the means for solving the problem are expressed in correspondence with the claims are those in which the items described in the claims are described in detail later. It shows that it corresponds to a member, a process, and an operation of at least one form among a plurality of forms of the above, but the solution means of the present invention is limited to the member of the embodiment indicated by those numbers. It is not for the purpose of clarifying the correspondence.

The centrifugal loading apparatus according to the present invention has a driving machine (5), a rotary table (6) rotated by the driving machine (5), and a test object mounted on the rotary table (6). 1
A first oscillating body (7) that oscillates about an axis and a second oscillating body (7) that oscillates about one axis on which a balance weight mounted on a rotary table (6) and having a mass commensurate with a test object is placed. 8) and a centrifugal controller (21) mounted on the rotary table (6), and the centrifugal controller (21) is virtually defined on a coordinate system fixed on the rotary table (6). The first moving line and the second moving line, each of which has a direction intersecting with the dynamic balance line
Multiple moving objects (25)
And a moving device for moving the moving body / plurality (25) while defining the coordinate position / plurality of the moving body / plurality (25).

Since a plurality of moving bodies move on the moving lines intersecting with each other, the center of gravity on the two-dimensional plane can be easily controlled, and the center of gravity of the centrifugal point can always be moved to the origin.

The first movement line and the second movement line are set symmetrically with respect to the dynamic balance line, and the first movement line and the second movement line are respectively arranged on the turntable (6). It is preferable to set symmetrically with respect to the rotation axis (3).
The moving body (25) can be moved to the two-dimensional plural positions calculated by the shortest line. The balance will not be greatly lost while moving. The balance point can be set at the optimum position.

The coordinate system is set on a two-dimensional plane, and
It is of course preferable that the dimensional plane is orthogonal to the rotation axis (3) line of the turntable (6). It is particularly preferable that the dynamic balance line is parallel to the two-dimensional plane and passes through the rotation axis (3) substantially orthogonal to the rotation axis in terms of calculation and control of the shortest time. It is further preferable that the first movement line and the second movement line are straight lines, are parallel to the two-dimensional plane, and pass through the rotation axis center line substantially orthogonal to the rotation axis center line (3).

The moving device comprises a moving driving machine (23) and a screw shaft (24) which is rotatably driven by the moving driving machine (23) and supported by a rotating table (6).
Is mechanically simple and can be controlled easily by rotating the screw shaft. Measurement for measuring the stress generated in the support base (1) or the same body that is the same body as the support base (1) that rotatably supports the rotary base (6) and that is generated in the support base (1) or the same body. Means (28, 29,
31), and a computer for calculating the movement amount of the moving body (25) between the measuring means (28, 29, 31) and the moving drive machine (23) as a function having the stresses as variables. .

The computer is a first computer (34).
And a second computer (35) and a third computer (38), and the first computer (34) has the following formula: Fx = k · {−x1 + x2 · cos (π / 3) + x3 ·
cos (π / 3)}, Fy = k · {x2 · sin (π / 3) + x3 · sin
(Π / 3)}. x1, x2, x3: 3 arranged at the same angle on the same circumference
It is particularly preferable to calculate the absolute value of the stress of one of the measuring means, k: a dimensional constant, and the second computer to calculate the average values Real and Imag of Fx and Fy during a certain period of time.

The third computer (38) uses the following formula: X1 = K · {Real · sin (θ) + Imag · co
s (θ)} / {2cos (θ) sin (θ)}, X2 = K · {Real · sin (θ) + Imag · co
s (θ)} / {2cos (θ) sin (θ)} X1, X2: the respective moving amount K of the moving body on the moving line K: a constant 2θ: particularly calculating the angle between the two moving lines preferable. With this kind of calculation, multiple real-time
5) can be moved to the optimum position.

The second computer (35) uses the following equations: Real = (1 / T) ∫ {Fx · cos (ωτ) dτ, Imag = (1 / T) ∫ {Fx · sin (ωτ) dτ. Integration range: Time (t +
It is preferable to calculate between T).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Corresponding to the figures, an embodiment of a centrifugal loading device according to the present invention is provided with a rotary drive mechanism. The rotary drive mechanism includes a support base 1.
A rotating shaft 2 is rotatably supported by a support 1. A rotation axis 3 of the rotation axis 2 is orthogonal to a horizontal plane that coincides with the ground L. The rotary shaft 2 is coupled to the electric motor 5 via a gear box 4 and a shaft coupling. A turntable 6 is connected to the rotary shaft 2. The turntable 6 is formed of both left and right arms, and has a structure that is substantially symmetrical with respect to the rotation axis 3 in terms of design.

The holder 7 for the test body and the holder 8 for the balance weight are arranged symmetrically with respect to the rotation axis 3 and are supported by a rotary table 6 and suspended swingably. The retainer 7 for a test body and the retainer 8 for balance weight have a structure which is substantially symmetrical with respect to the rotational axis 3 in design. The holder 7 for the test body and the holder 8 for the balance weight are rotatably supported by hanging shafts 9 and 11, respectively. The hanging shafts 9 and 11 are parallel to each other and are horizontally fixed, and are fixed to the turntable 6.

A centering connecting shaft 12 connected to the upper end of the rotating shaft 2.
Is connected to a slip ring 13 for passing operation lines such as electric wires and hydraulic lines. Electric wires, hydraulic pipes, etc. are passed through the centering connecting shaft 12 and the slip ring 13. The slip ring 13 is fixed and supported by a ceiling-side frame 15 that forms the ceiling wall of the test apparatus. The test body 16 is loaded on a platform formed on the test body holder 7. Balance weight 17
Are mounted on the platform formed on the balance weight holder 8.

A sub-weight moving mechanism 21 for moving the sub-weight for centrifugal (or eccentricity) adjustment is arranged and attached to the upper surface of the rotary table 6. The sub-weight moving mechanism 21 is formed by two pairs of moving mechanisms, as shown in FIG. A coordinate system XY is set on a horizontal plane which is the upper surface of the rotary table 6. Machine origin is coordinate system X-
It is set so as to coincide with the origin O of Y. Origin O
Is on the axis of rotation 3.

The two pairs of moving mechanisms 21 include a pair of first moving mechanisms 21-1 and another pair of second moving mechanisms 21-2. The first moving mechanism 21-1 is composed of a first one-side moving mechanism 21-11 and a second other-side moving mechanism 21-12. The second moving mechanism 21-2 includes a second one-side moving mechanism 21-21 and a second other-side moving mechanism 21-22. The moving mechanism 21 rotates integrally with the coordinate system XY fixed to the turntable 6.

The first one-side moving mechanism 21-11 and the first other-side moving mechanism 21-12 have a structure symmetrical with respect to the rotation axis 3. Second one side moving mechanism 21-2
The 1st and 2nd other side moving mechanism 21-22 is a rotating shaft center line 3
It has a structure that is symmetrical with respect to. First moving mechanism 2
The 1-1 and the second moving mechanism 21-2 are congruent and are arranged symmetrically with respect to the X axis. As a matter of course, the moving mechanism 21 is symmetrical with respect to the X axis, the Y axis, and the rotation axis center line from the above symmetrical structure.

Only the first one side moving mechanism 21-11, which is one of the four moving mechanisms, will be described below. The first one-side moving mechanism 21-11 includes a feed drive source 23, a feed screw 24, and a moving body 25 that is a subweight. One end of the feed screw 24 is axially connected to and supported by the feed drive source 23, and the other end is rotatably supported by the bearing 26. The relationship between the feed screw 24 and the moving body 25 is preferably conventional ball-screw feeding, and the moving body 25 is guided non-rotatably by a guide body (not shown). A servomotor is suitable as the drive source 23.

The screw axis of the feed screw 24 is defined as the line of movement along which the moving body 25 moves. The movement line 27 is preferably a straight line, is on a plane (horizontal plane, XY plane, rotation plane) orthogonal to the rotation axis 3 and passes through the rotation axis 3. First one side moving mechanism 2
1-11 movement line 27 and first other side movement mechanism 21-12
The line of movement 27 is on a straight line. The moving line 27 of the second one side moving mechanism 21-21 and the second other side moving mechanism 21-2
The moving line 27 of 2 is on a straight line. The angle between these two lines of travel is 2θ. The angle between these movement lines 27 and the X axis is θ.

FIG. 3 shows a cross section of the support base 1, which is a part of the rotating mechanism, taken along a horizontal plane. FIG. 4 shows a stress measuring method. On the cross section of FIG. 3, the outline of the support base 1 is strictly a circle. First at the intersection where the X-axis intersects the circle
A strain gauge 28 is arranged. The angular coordinate of the X axis is set to zero. The second strain gauge 2 is located at the intersection point where the line obtained by rotating the X axis in the positive direction by 2π / 3 on the XY plane that is the plane of rotation intersects the circle.
9 are arranged. 2π / on the XY plane with the X axis in the negative direction
A third strain gauge 31 is arranged at an intersection point where a line rotated by 3 intersects the circle. In addition, a limit switch that defines the stroke end of the moving body 25, and a rotation speed detector that uniquely detects the rotation speed of the feed screw 24 that the drive source 23 that is a servo motor has are provided.

FIG. 4 shows a centrifugal control device circuit of the centrifugal loading device according to the present invention. A stress measuring device 32 including a first strain gauge 28, a second strain gauge 29, and a third strain gauge 31 outputs stress equivalent signals S1, S2, S3 corresponding to the stress detected by these strain gauges. Stress equivalent signal S1,
S2 and S3 are converted into digital signals by the A / D converter 33 and input to the centrifugal action force calculator 34. The centrifugal action force calculator 34 can calculate the X-axis direction action force vector Fx and the Y-axis direction action force vector Fy acting on the support 1.

The respective series signals of the X-axis direction acting force vector Fx and the Y-axis direction acting force vector Fy obtained on the time series are input to the vector filter 35, and the average value per set unit time is calculated, The average value signal 36,3
7 is output to the moving body position / direction calculator 38. The moving body position / direction calculator 38 outputs four moving position signals 39, 41, 42, 43 corresponding to the four moving bodies 25 to the operation command unit 44. The operation command unit 44 calculates the rotational speed positions of the four feed screws 24 based on the movement position signals 39, 41, 42, 43, and causes the servomotors of the four drive sources to rotate. In this case, it is preferable to use the D / A converter 45.

At the start of the test, the test body 16 is loaded on the test body holder 7, and the balance weight 17 is placed on the balance weight holder 8. Although the mass of the test body 16 and the mass of the balance weight 17 are almost equal, the test body 1
It is difficult to set the center of gravity of each of 6 and the balance weight 17 at a position symmetrical with respect to the rotational axis 3.

The electric motor 5 is started to rotate the turntable 6,
When the speed of rotation is increased, the retainer 7 for test body and the retainer 8 for balance weight gradually rotate in opposite directions and swing up, and the retainer 7 for test body originally oriented in the vertical direction. The balance weight retainer 8 eventually faces the substantially horizontal direction. If the test body 16 is a scale model of 1 / N of the actual product, the maximum rotational speed of the test body holder 7 and the balance weight holder 8 is set so that the centrifugal acceleration acting on the holder 7 and the balance weight holder 8 becomes N times the gravitational acceleration. Is set. As a result, it is possible to conduct a test in an actual environment.

First, second and third strain gauges 28, 29, 31
The signals S1, S2, S3 output by the can be displayed on the display. From the magnitudes of the signals S1, S2 and S3, the moving directions of the four moving bodies can be determined empirically as a rule. As an empirical rule, it is possible to adjust the movement of the moving body so that the magnitudes of the signals S1, S2, and S3 become smaller, but it is uncertain whether or not the adjustment is optimal.

Optimal adjustment and control can be performed physically and automatically by the centrifugal control device circuit shown in FIG. As shown in FIG. 5, the stress vectors x1, x2, and x3 acting on the first, second, and third strain gauges 28, 29, and 31 are decomposed in the X-axis direction and the Y-axis direction, and the X-direction stress vector is obtained. Fx and the Y-direction stress vector Fy are expressed by the following equations.

Fx = k · {−x1 + x2 · cos (π / 3) + x3 · cos (π / 3)}, Fy = k · {x2 · sin (π / 3) + x3 · sin (π / 3)}. .. (1) Here, k is a dimension constant. Formula (1) is calculated by the centrifugal force calculator 34. Fx and Fy are values detected by sampling, and are numerical sequences that are discrete values on the time sequence, but for convenience, they are continuous values, and the following filter processing can be expressed.

Real = (1 / T) ∫ {Fx · cos (ωτ)} dτ, Imag = (1 / T) ∫ {Fx · sin (ωτ)} dτ. (2) ω: rotational angular velocity integration range of the rotary shaft 2: time (t +) when a certain time T has passed from time t
During T), Real and Image are good average values of the stress in the X and Y directions per unit time T.

FIG. 6 shows centrifugal force-induced stress vectors Fx, F.
A projection projection decomposition vector A, A'to the movement line 27 of y,
B and B'are shown. A = (Imag / 2) / sin (θ), B = (Real / 2) / cos (θ). (3) The composition (A + B) of the vector on the moving line 27 of the first quadrant and the vector B is: A + B = (Real / 2) / cos (θ) + (Imag / 2) / sin (θ) = Real · sin (θ) + Imag · cos (θ) /(2sin(θ)cos(θ)...(4) Regarding the moving line in the fourth quadrant, A ′ + B ′ = Real · sin (θ) − Imag · cos (θ) / (2sin (θ) cos (θ) ... (5)

The moving body 25 is moved in a direction indicated by an arrow a in the figure so that the centrifugal force-induced stress on the moving line is canceled, that is, the vector (A + B) has the same magnitude but the opposite direction. To move. The movement amount X1 is calculated by using a mechanical system design constant K related to the mass of the moving body, and X1 = K · (A + B) = K · {Real · sin (θ) + Imag · cos (θ)} / {2cos (Θ) sin (θ)}. (6) Similarly, the moving amount X2 of the moving body on the other moving line is: X2 = K · {Real · sin (θ) −Imag · cos (θ)} / {2cos (θ) sin (θ )}. ... (7)

Such a movement amount is represented as a difference X1, X2 of the movement amounts of the four moving bodies, and in reality, it is 4
The two moving bodies are individually driven to move. If it is difficult to move the moving object to the origin O due to the machine layout,
It is effective to move four bodies. The calculation of equations (6) and (7) is executed by the moving body position / direction calculator 38. Signal 3
Based on 9, 41, 42, 43, the rotation speed of the drive source 23 is calculated by the operation command device 44.

The centrifugal adjustment control by such position control is executed during the rotation of the rotary table 6 at the specified maximum speed. Since this control is performed by physical calculation, trial and error and empirical rules are not necessary. Finer adjustments can be made artificially. When the three stresses reach the minimum values, the drive source (servo motor) 23 can be fixed by electrical control (servo).

The elimination of the dynamic imbalance by automatic control is
It can be done almost instantly. The experiment is performed quickly and its accuracy is higher. Dynamic imbalances caused by test specimens such as embankments are resolved in near real time. The dynamic imbalance in any direction on the two-dimensional surface caused by the test body such as embankment is also eliminated in almost real time. The continuous dynamic imbalance caused by pumping a fluid such as water into the test specimen is continuously eliminated. The dynamic imbalance of the test body that evaporates and changes its mass is also eliminated in real time.

As the moving means of the moving body, a linear driving means such as a fluid pressure cylinder, a chain or a slider can be used. It is preferable to issue a warning when the moving body is forced to reach the end stroke.

The averaging method is not limited to the filter processing as in the equation (2), and various conventional methods such as the least square method can be adopted. The moving method of the moving body is not limited to the point-symmetrical movement of the one-to-two body, and it is also possible to move the four bodies individually.

[0038]

The centrifugal loading device according to the present invention can eliminate the dynamic imbalance on a two-dimensional surface during rotation. Furthermore, it can be solved in real time. Even when the position of the center of gravity and the mass of the test body fluctuate, the imbalance can be eliminated almost continuously in real time.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a centrifugal loading device according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a plan sectional view showing an arrangement of control devices.

FIG. 4 is a circuit block diagram of a control device.

FIG. 5 is a vector exploded view.

FIG. 6 is a vector composition diagram.

[Explanation of symbols]

3 ... Rotation axis center line 5 ... Drive 6 ... Turntable 7 ... First oscillating body (bucket) 21 ... Centrifugal control device 25 ... Moving body / plurality 23 ... Moving drive 28, 29, 31 ... Measuring means 34 ... First calculator 35 ... Second computer 38 ... Third computer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-18866 (JP, A) JP-A-6-74852 (JP, A) JP-A-2-186231 (JP, A) JP-A-2- 35950 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01M 19/00

Claims (2)

(57) [Claims] 1. A drive machine, a turntable which is rotationally driven by the drive machine, a first swinging body which is mounted on the turntable and places a test object and swings about one axis, and the turntable. And a second oscillating body that oscillates about one axis on which a balance weight having a mass commensurate with the test object is mounted, and a centrifugal control device mounted on the rotary table. , A movement that moves on a first movement line and a second movement line that each have a direction that intersects with a dynamic balance line that is virtually defined on a coordinate system that is fixed on the rotating table. A plurality of bodies, and a moving device for moving the plurality of moving bodies while defining the plurality of moving bodies, a plurality of coordinate positions, and a plurality of the moving bodies, and the coordinate system is set on a two-dimensional plane, and the two-dimensional Plane
Is orthogonal to the axis of rotation of the turntable, the dynamic balance line is parallel to the two-dimensional plane, and
The axis of rotation approximately perpendicular to the axis of rotation.
And the first movement line and the second movement line are straight lines, and
It is parallel to the two-dimensional plane and at the axis of rotation.
A support base that rotatably supports the rotary table or the support table that rotatably supports the rotary table.
The support is attached to an object which is the same body as the support, or
Measuring means for measuring stress generated in the same body object
And the moving body between the measuring means and the moving drive machine.
To calculate the amount of movement as a function with the stress as a variable.
And a first computer, a second computer, and a second computer .
3 and a computer, the first computer, the following equation; Fx = k · {-x1 + x2 · cos (π / 3) + x3 · cos (π / 3)}, Fy = k · {x2 · sin (π / 3) + x3 · sin (π / 3)}. x1, x2, x3: 3 arranged at the same angle on the same circumference
The absolute value of the stress of one of the measuring means, k: a dimensionless constant is calculated, and the second computer calculates the flatness of the Fx and Fy for a certain period of time.
The average value Real and Imag are calculated, and the third computer calculates the following formula: X1 = K · {Real · sin (θ) + Imag · cos (θ)} / {2cos (θ) sin (θ)}, X2 = K · {Real · sin (θ) + Imag · cos (θ)} / {2cos (θ) sin (θ)} X1, X2: Transfer of each of the moving bodies on the moving line
Momentum K: Constant 2θ: Centrifugal loading device characterized by calculating an angle between both moving lines . 2. The method according to claim 1 , wherein the second computer has the following expression: Real = (1 / T) ∫ {Fx · cos (ωτ)} dτ, Imag = (1 / T) ∫ {Fx · sin ( ωτ)} dτ. Integration range: Time (t +
Centrifugal loading device characterized by calculating between T).