JPH0454428Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a multi-force measuring device that measures components of force and moment acting on a certain point on an object.

[Conventional technology]

In mechanical testing of various materials or devices, it is necessary to accurately understand the force and moment acting on a specific point. In order to accurately measure forces and moments acting in any direction, a method is generally adopted in which they are measured as component forces in each direction. The forces and moments acting on a single point on an object are represented by three types of forces F _X , F _Y , F _X and three types of moments M _X , M _Y , M _Z in the orthogonal coordinate system of FIG. These are usually called 6-component forces, and by combining the 6-component forces, forces and moments in all directions can be expressed.

Such six component forces acting on an object are calculated from various component forces acting on a sensor called a multi-force detector connected between the object to be tested and a fixed stand.

For example, when a model of an aircraft is disposed in a wind fuselage and various component forces acting on the body of the aircraft in the air are to be measured, the arrangement shown in FIG. 2 is adopted. Wind fuselage 1
The aircraft model 2 introduced into the wind turbine is connected via a strut 3 to a multi-force detector 4 on a fixed stand 5 outside the wind fuselage. In this test, multiple forces acting on the measurement center MC of the aircraft model 2 are detected.

If detector 4 is inside the model, this detector will also be able to directly measure the moment center.
Although there may be cases where it is possible to match the MC, such installation is generally extremely difficult and requires careful consideration in structural design and complex assembly and setting work. Therefore, the detector 4 is often installed outside the model, as in the arrangement shown in FIG. However, even in this case, it is difficult to calculate the component force at the measurement center of the model from the output of the detector. The reason for this will be explained below.

FIG. 3a shows an example of a moment detector in which strain gauges A, B, C, and D are attached to a beam 6 for moment detection. At the lower end of the detection beam 6 is a flange 7 that is fixed to the fixed base 5. Strain gauges A and B are mounted on one surface 8 of the detection beam 6, and strain gauges C and D are mounted on the other surface 9, respectively.
It is pasted as shown. If the distance between the point 11 where a force like arrow F acts and the center 10 of strain gauges A, B, C, and D is L, then strain gauges A, B,
The output e of the bridge circuit in which C and D are connected as shown in Fig. 3c can be expressed by the following equation, e∝∝F _X L (1).

It is obvious that this F _X L is the moment generated at the center 10 of the strain gauge. In this way, it is easy to determine the moment acting on a predetermined point inside the detector.

However, if the measurement center MC does not coincide with the detector in the arrangement shown in FIG. 2, special consideration is required because the output of equation (1) does not indicate the force acting on the measurement center MC. To determine the moment in such an arrangement, for example, a pyramid-type multiforce detector is used, but the structure and operation of this detector are complex and expensive. Furthermore, the measurement center must be accurately aligned with the center of the pyramid of the detector, which poses maintenance problems, making installation and operation difficult.

[Problem for invention]

The purpose of this invention is to significantly reduce the drawbacks of the conventional devices described above, and to provide an inexpensive device that measures multiple forces with high accuracy, excellent reproducibility, and excellent operability. shall be.

[Means for solving problems]

The above problem can be solved by using a multi-force detector 4 fixed to a stationary or movable reference member 5.
and a support connecting member 3 to which the multi-force detector is fixedly connected to one end and the object to be measured 2 can be detachably fixed to the other end, and the output signal of the component force detected by the multi-force detector is as follows. The formula, M _X = M _X ′−L _2X F _Y M _Y = M _Y ′ + L _{1X F} As,
M _{X , M Y} : Moment around the x and y axes at the measurement _{center ,} M force x,
y component, L ₁ , L ₂ : Distances from the measurement center to the moment detection part around the x and y axes of the multiforce detector, respectively, are used to perform analog calculation processing and output the multiforce value applied to the object to be measured. The arithmetic processing device is arranged to amplify the output signals of the forces (F _x , F _y ) in the x and y directions supplied from the multi-force detector 4, and the arithmetic processing device is provided with a connecting conductor, respectively. Pre-stage amplifiers (A _F1 ; A _Fx1 , A _Fy1 ) connected via
and rear-stage amplifiers (A _F2 ; A _Fx2 , A _Fy2 ) are connected in sequence to amplify the moment output signals (M _x ′, M _y ′) in the x and y directions supplied from the multi-force detector. The pre-amplifier (A _M1 ; A _Mx1 ,
A _My1 ) and an adder with two inputs (T _x , T _y )
and between the second stage amplifier (A _M2 ; A _Mx2 , A _My2 ), the other input end of the adder for the x- and y-direction moments, and the connection conductor for the y- and x-direction force amplification system, respectively. Electrically connected coefficient setter (K _a ,
K _b ) and all pre-stage amplifiers (A _F1 ,
A _F2 ; A _Fx1 , A _Fy1 ; A _Fx2 , A _Fy2 ), all post-stage amplifiers (A _F2 , A _M2 ; A _Fx2 , A _Fy2 ; A _Mx2 , A _My2 ) and the coefficient setters (K _a , K _b ) is solved by a multi-force measuring device that can variably set the amplification factor from the outside.

[Effect of the invention] The multi-force measuring device with the above-mentioned configuration uses a commercially available multi-force measuring device and simply adds a simple analog processing device, and after a simple initial setting operation, it can measure the object to be measured. The actual value of the multiforce applied to (type) can be automatically obtained as an analog value,
Mechanical properties (forces and moments) that occur in various models
To measure this, it is sufficient to simply replace the model, and there is no need to replace the measurement system (commercially available multi-force measuring device and analog processing device added by this invention). Therefore, cost savings and ease of operation can be expected.

〔Example〕

This invention will be explained in more detail below based on examples.

FIG. 4 is a configuration diagram for explaining the basic functions of the multi-force measuring device according to this invention. The strut 21, which has a measurement center MC near its tip, is connected at its lower end to an existing (ie, for example, commercially available and commonly used) multi-force detector 22. This detector 22 is further fixed to a fixed base 23. It is assumed that the distance between the moment center 24 of the detector 22 and the measurement center MC is L. When the force of the white arrow F and the moment of the arrow M act simultaneously on the measurement center MC in such an arrangement, the force F and the moment M' act on the moment center 24 of the detector. The following relationship exists between the moments M and M': _M '=M+F The moment M is calculated from the output of the detector 22 as follows: M=M'- _FXL (2').

FIG. 5 shows output signals M' and F corresponding to the moment M' and force F supplied from the detector 22 based on equation (2') (hereinafter, to avoid complexity, the corresponding electrical signals are also mechanical quantities. ), the moment M and force F acting on the measurement center MC are
A block diagram of the power supply circuit of the component force measuring device according to this invention, which is capable of calculating .

The force output signal F supplied from the detector 22 is
The signal is introduced from an input conductor 33 to an amplifier 31 whose amplification factor A _F1 can be varied from the outside, and the output signal of this amplifier 31 is introduced to another amplifier 32 via a conductor 34. The output signal F' of this amplifier 32 then appears on the output conductor 35. Here, the amplification factor A _F2 of the amplifier 32 can also be varied from the outside. The moment output signal M ₁ supplied from the detector 22 is introduced via an input conductor 39 into an amplifier 36 , the output signal of which is applied via a conductor 40 to one input of an adder 38 . be introduced. Adder 38
The output signal of is introduced via conductor 42 into amplifier 37, which outputs an output signal M ₂ via output conductor 43. In this case, amplifier 38
Both the amplification factors A _M1 and A _M2 of 37 can be changed externally. Further, the output signal of the amplifier 31 is transmitted through the conductor 34.
The signal is branched from the coefficient setter 41 and the output signal of the setter 41 is inputted to the other input terminal of the adder 38. Here, the coefficient setter 41 serves to multiply the signal on the conductor 34 by K times, and K can take positive and negative values.

In the example of FIG. 5, amplifiers 31, 32, 36, 3
By appropriately selecting the amplifiers A _F1 , A _F2 , A _M1 , A _M2 and the coefficient K of the coefficient setter 41, the detection signals F and M ₁ corresponding to the force and moment supplied from the detector 22 can be set. , can be converted into predetermined values F' and _M2 for display or recording that are proportional to these values.

Furthermore, after setting the coefficient K of the coefficient setter 41 to correspond to the distance L using a dial or digital switch, etc., the amplification factors A _F1 , A _F2 , A _M1 ,
Since it is possible to adjust A _M2 , the following characteristics can be obtained.

That is, when the above adjustment is completed, the coefficient K
The value corresponds to the distance from the moment center of the detector to the measurement center of the model. Therefore, even if the position of the measurement center MC of the model moves with respect to the detector 22, the component force measuring device according to this invention can be reused as is by changing the coefficient K appropriately.

Initial adjustment of the power supply circuit shown in FIG. 5 can be performed by the following procedure.

First, A _F1 , A _F2 , A _M1 , and A _M2 are set to arbitrary non-zero values.

Set K to be the distance between the position of force F and the moment center of the detector.

Apply force F.

Under that condition, adjust A _F2 so that the output F′ becomes the input F
Set to a predetermined value proportional to .

Furthermore, A _M1 is adjusted so that the output _M2 becomes zero.

A moment M is added to adjust A _M2 , and the output _M2 at that time is set to a predetermined value proportional to the input M.

If )~) operations are not possible,
Change A _F1 and A _M1 and repeat steps ) to ).

Fig. 6 shows a power supply circuit of a component force measuring device according to this invention in which a system like that shown in Fig. 2 uses a six-component force detector 4 having a moment center inside, and measures all component forces. A block diagram is shown. The component force acting on the measurement center MC corresponding to the component force detected by the detector 4 is the same for the force component,
In the case of the moment component, M _X = M _X ′−L _2X F _Y M _Y = M _Y ′+L _1X F _X (3). The symbols in FIG. 6 have the same meanings as the corresponding symbols in FIG.
The three orthogonal components of the component forces and the subscripts 1 and 2 distinguish the front stage or the rear stage of the amplifier. K _a , K _b
is a coefficient setter corresponding to the coefficient setter K designated by reference numeral 41 in FIG.

In the case of equation (3), the distance L ₁ between the measurement center MC and the measurement center of the Y-direction moment of the detector is the measurement center MC
and the distance between the detection center of the X-direction moment of the detector
Even when L ₂ is different, that is, when L ₁ ≠ L ₂ , the coefficient K ₁ is made to correspond to L ₁ , and
By making K ₂ correspond to L ₂ , the moment at the measurement center MC of the model can be measured independently. Therefore, the moment center of the detector M _X ′,
It is no longer necessary to match the detection points of the detector for M _Y ′ and M _Z ′ to one point.

Furthermore, it goes without saying that the above-mentioned contents can also be applied to cases other than the Z direction, for example, the X and Y directions, or a combination thereof.

Furthermore, this device is not limited to 6-component force measurement, but can be applied to any detector that combines force and a moment in which a moment due to the force is added to the measured value. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing six components of force in an orthogonal coordinate system. FIG. 2 is a schematic diagram illustrating the basic configuration of a component force measuring device for an aircraft model in a wind fuselage. Figures 3a and 3b are schematic diagrams showing the arrangement of the detection beam and strain gauges;
The wiring diagram of the strain gauge used in FIGS. 3c, 3a, and 3b. FIG. 4 is a side view of the basic configuration of the component force detection unit according to this invention. FIGS. 5 and 6 are basic block circuit diagrams for analog calculation of component force output signals. Reference symbols in the figure: 1... Wind fuselage, 2... Wind fuselage model,
3...Strut, 4,24...Multiple force detector,
5...Fixed stand.

Claims (1)

[Claims for Utility Model Registration] A multi-force detector 4 fixed to a stationary or movable reference member 5, the multi-force detector fixedly connected to one end, and an object to be measured 2 attached to and detached from the other end. _{The output} signal of the component force _detected by the support _connecting member 3 _that can be fixed and the multi-force detector _is expressed _by the following _formula , M Here, the straight line connecting the measurement center of the object to be measured and the measurement origin of the multi-force detector is defined as the z-axis,
M _X , M _Y : Moment around the x and y axes at the measurement center, M _X ′, M _Y ′: Moment around the x and y axes at the multiforce detector, F _X , F _Y : Multiforce detector The x and y components of the force acting on the object, L ₁ and L ₂ : the distance from the measurement center to the moment detection part around the x and y axes of the multi-force detector, respectively, are used to perform analog calculation processing and are applied to the object to be measured. In the multiforce measuring device, the arithmetic processing device outputs an applied multiforce value.
A front _{-stage amplifier (A F1 ;} A _Fx1 , A _Fy1 ) and a rear _- stage amplifier (A _F2 ; A _Fx2 , A _Fy2 ) and a pre _{- stage} amplifier ( A _M1 ; A _Mx1 , A _My1 ), an adder (T _x , T _y ) with two inputs, a post-stage amplifier (A _M2 ; A _Mx2 , A _My2 ), and the adder for moments in the x and y directions. the other input end of the device and the y and x
It consists of coefficient setters (K _a , K _b ) electrically connected between the connecting conductors for the directional force amplification system, and all pre-stage amplifiers (A _F1 , A _Fx2 ; A _Fx1 ,
A _Fy1 ; A _Fx2 , A _Fy2 ), all post-stage amplifiers (A _F2 ,
A multiforce measuring device characterized in that the amplification factors of A _M2 ; A _Fx2 , A _Fy2 ; A _Mx2 , A _My2 ) and the coefficient setting device (K _a , K _b ) can be variably set from the outside.