JPH02253131A - Measuring instrument - Google Patents

Abstract

PURPOSE:To simultaneously measure respective components in three-dimensonal directions and various physical quantities by operating and converting an external force to an acceleration, a velocity, a frequency, or the like based on the electromotive force of a piezoelectric element which is displaced together with a body to be measured. CONSTITUTION:A body 2 to be measured is supported in a reference body 1, which is formed into a regularly hexahedral hollow box with materials having rigidity, by plural piezoelectric elements 3. Plural piezoelectric elements 3 are arranged in each of three x-axis, y-axis, and z-axis directions; and when the reference body 1 is oscillated by reception of a specific external force F, elements 3 generate the electromotive force corresponding to the extent of displacement due to expansion and contraction while expanding and contracting in accordance with the displacement of the body 2 to be measured. An operating part 4 uses a prescribed conversion formula to perform prescribed operation based on the electromotive force outputted from piezoelectric elements 3 and calculates various physical quantities acting on the body 2 to be measured in a certain direction, and measured force, acceleration, velocity, frequency and their numerical values or the like are displayed on a display part 5.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a measuring device capable of measuring various physical quantities such as vibration, acceleration, velocity, and frequency, and particularly to a measuring device that can measure the physical quantities in three-dimensional directions. The present invention relates to a new measuring device that can perform simultaneous measurements.

[Conventional technology]

2. Description of the Related Art Conventionally, various measuring devices have been developed and used as means for measuring various physical quantities, such as force, acceleration velocity, vibration frequency, and the like.

[Problem to be solved]

By the way, such a measuring device is generally inconvenient because it can only measure one direction and one type of physical quantity with one device. In addition, such a measuring device
In general, many of them are large and heavy, and their manufacturing costs are correspondingly high.

Therefore, in view of the above-mentioned drawbacks of the conventional technology, the present invention is capable of simultaneously measuring each component in three-dimensional directions with a single device, and also being able to measure various physical quantities, while being lightweight and compact. The purpose of this invention is to provide a measuring device that is easy to measure.

[Means to solve the problem]

That is, the present invention provides a stationary body which is normally stationary with respect to an absolute coordinate system and is attached to move when an external force is applied, and a casing of the stationary body by means of piezoelectric elements arranged in each direction orthogonal to each other. The electromotive force output from an internally supported measured object with a constant mass and a piezoelectric element that is displaced along with the displacement movement of the measured object is manually generated, and based on this, calculations are performed using a predetermined conversion formula. The apparatus includes a calculation section that calculates and converts the external force into physical quantities such as component force, acceleration, and velocity frequency in a predetermined direction of the object to be measured.

[Effect]

In the measuring device of the present invention, when the object to be measured undergoes a movement displacement due to the action of an external force, a specific force acts on each piezoelectric element along with the displacement movement, and an electromotive force is generated in the piezoelectric element. A calculation unit using human power performs calculations using a predetermined conversion formula, thereby calculating physical quantities such as force, acceleration, velocity, and frequency that act on the object to be measured in a specific direction.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a measuring device according to the present invention, which includes a reference body 1, a measured body 2, and a piezoelectric element 3.
It is composed of a calculation section 4 and a display section 5.

As shown in Figure 2, the reference body 1 is made of a rigid material and is shaped like a regular hexahedral hollow box, and is designed so that it is normally stationary with respect to the earth (absolute coordinate system). Although it is fixed, it is made to move by the action of an external force.

The object to be measured 2 is vibrated and displaced into the reference object I by the action of an external force in order to observe various physical quantities, and has a mass M.
A spherical member is used, and is supported inside the reference body 1 by a piezoelectric element 3, which will be described next.

The piezoelectric element 3 expands and contracts with the displacement of the object to be measured 2 due to the action of an external force, and generates an electromotive force according to the amount of expansion and contraction. In this embodiment, as shown in FIG. A total of six sensors are arranged, two in each of the original three directions, that is, x, y, and z, and each is connected to the input end of the calculation section 4. That is, the piezoelectric element 3 of this embodiment has the first . Second piezoelectric element 3
a, 3b and the third along the X direction. Fourth piezoelectric element 3c, 3
d and the fifth along two directions. It is composed of sixth piezoelectric elements 3e and 3f. Note that the piezoelectric element of the present invention may be configured with a total of three piezoelectric elements, for example, one in each of the three directions of x, y, and z.

The calculation unit 4 calculates various physical quantities acting on the object to be measured 2 in a certain direction by performing predetermined calculations based on the electromotive force output from the piezoelectric element 3 using a predetermined conversion formula that will be explained later. A microcomputer is used in this embodiment.

The display unit 5 displays data on various physical quantities calculated by the calculation unit 4, and displays the types of measured physical quantities, ie, force and acceleration, on the screen.

The speed 1 vibration frequency and its numerical value are displayed.

Next, a calculation method for calculating various physical quantities based on the electromotive force generated from the piezoelectric element in the measuring device of this embodiment will be explained.

First, as shown in FIG. 2, when the reference body 1 vibrates under a specific force F, the amount of displacement of the measured body 2 that is displaced by the force F is expressed as (f(t)), ry (t), f, (t)
). Here, in order to simplify the explanation, we will examine the displacement of one component, namely the X component.

That is, in FIG. 3, the X component F of the force F causes the first
．． A resistance force R is generated in the second piezoelectric elements 3a and 3b, but
The resistance force R can be expressed as a function of X, R(x). Therefore, by developing this resistance R(x) with a tiller, R(!1l=cOX +c I father + C2 father +...
・+C+, x ”'+−−・−・− However, generally up to the second term is sufficient approximately,
Therefore, it can be expressed as the following formula, that is, Rfxl ~ CoX + [: + x
, , , , ・■.

Now, if we set up a new coordinate system (hereinafter referred to as the absolute coordinate system) o-x' in which the amount of displacement f of the object to be measured 3 in the X direction is 0, as shown in Fig. 4. , a relational expression as shown in the following expression, that is, a coordinate transformation expression is established between them.

x = x + f ・・・・・・■
Here, in this coordinate transformation formula (■), for time t, 2
By performing step differentiation, the following equation is obtained.

Father ° − Father + 78 ・・・・・・■
By the way, in general, the mass m has the relationship shown in Figure 4.
The following motion method has been established for the measured object 2, that is, m father' + 2 C large + 2 k x = O
(elastic constant, C is damping coefficient) Here, substituting the 0 expression into the 0 expression, mx-4-2cx+2kx= -m? t+ +++
...■If you transform this 0 expression, father + 2ε sentence + w n' x = -? +1 ””
"■" (However, here ε-C/m, ω2 = 2, 7m) By the way, in general, for a differential equation like ■°, the general solution χ (displacement of the measured object) is x = a -exp
It has a function form such as [−αt]·5in (β is 10ψ) and is an attenuation function, so in the case of this embodiment, only the special solution needs to be completed.

By the way, when the displacement f is subjected to Fourier expansion, f
Party Ci6 exp [int] --
−−−−■ Therefore, (++= -immune n 2・Ch-exp C1ntlHere, if we put ah−−n2Co ......■, now, here, f The nth term of II8? About Xn If you think about it, in the formula ■′, father, +2ε sentence.+ ωIl'xI+=-?jjha7
° eXp I:inl, ] -----,■
(from the formula, “, ■) Here, xl, = a ・exp [iBt ] − ■
Then, by substituting ■ and ■ into ■, αβ2・ey, p [i βt]+21εαβ' e
xp[1βt] + ω, 'a conflict ex
p ['i βt]ah'exp [i n
t] To put it in order, in order for the formula 0 to hold when 0≦t×■, it must be n−β.

Therefore, at this time, from equation 0, an -a (-n2+2 εi n+rn2°)...
...0 is obtained.

By the way, from the formula (■), a,, --n2c,, so if we set, then from the formula (■) and (■), X n-αIl' Ch. exp [int] α.・f
,, (from ,−,■) By the way, the displacement Sentence-Lα, Su.

(t) + fiα. f, (t) Also, the acceleration at this time is Father=2fia,? , (t)+fiα. ¥, (1) 10j
δ. r, (t) Also, the force F8 acting on the measured object 2 at this time is Fx
=m-father m [2fian・i, (L) + tachiαhYX(t)-t-yund. f, (t)] or more, X
Although we have calculated this for each component, the y and z components can also be calculated in the same way.

Also, the combined speed V at this time is V-・×2+
, 2+22, and also for the acceleration α synthesized for each of these components, α−"・'+ V '+, p'-,
The combined force F for each of these components can be found from

〔effect〕

As explained above, according to the measuring device according to the present invention, when the object to be measured undergoes a movement displacement, an electromotive force is generated from the piezoelectric element along with the displacement operation, and the calculation unit uses the generated electromotive force to generate an electromotive force. performs predetermined calculations and can calculate physical quantities such as force, acceleration, and velocity frequency acting on the object to be measured for each three-dimensional component, so there is no need to use large, special, and expensive equipment. can also be easily measured.

Further, according to the measuring device according to the present invention, various physical quantities can be measured using only the electromotive force generated from the piezoelectric element, which is extremely practical.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a measuring device according to the present invention, and FIG. 2 is a perspective view showing a reference body used in the measuring device according to the present invention and a measured object attached to the reference body by a piezoelectric element. , FIG. 3, and FIG. 4 are explanatory diagrams for explaining the operation of the measuring device according to the present invention, respectively. 1... Reference body, 3 Piezoelectric element 2... Measured object, 4... Arithmetic unit.

Claims (1)

[Claims] 1. A stationary body that is normally stationary with respect to an absolute coordinate system and is attached to move when an external force is applied, and the stationary body is fixed by piezoelectric elements arranged in each direction orthogonal to each other. An object to be measured with a constant mass supported inside the casing of the device and the electromotive force output from a piezoelectric element that is displaced along with the displacement movement of this object to be measured are input, and calculations are performed using a predetermined conversion formula based on this input. A measuring device comprising: a calculating section that calculates and converts the external force into physical quantities such as component force, acceleration, velocity frequency, etc. in a predetermined direction of the object to be measured.