JPH06265423A - Multicomponent force detector - Google Patents

Abstract

PURPOSE:To provide a multicomponent force detector by which measurement having high accuracy and reproducing ability can be executed for the six component forcs at the maximum without mutual interference. CONSTITUTION:Four flat plate beams 3 to 6 are arrangedly provided between a fixed flange 2 and a measuring flange 1, and strain gauges are severally stuck to the sides of both the flanges 1, 2 of each of 3 faces except the side of each beam opposite to the axes of both the flanges 1, 2 and two spots adjacent to the center of the flanges 1, 2. In this case, the detecting directions of two latter strain gauges are the longitudinal direction of the beam on one side and a direction perpendicular to the above one on the other side. These strain gauges are properly combined to form a bridge circuit which can take out only individual component force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-component force detector capable of detecting up to 6 component forces with a single body.

[0002]

2. Description of the Related Art When various forces are externally applied to an object, a maximum of six kinds of forces and moments act on the object. Conventionally, a load cell has been used as a means for measuring these quantities. However, the load cell only measures the force in that direction, assuming that only the force in the simplest direction is applied to the force acting system, and when a component force other than the force to be measured acts. Cannot avoid its interference. Various technical considerations have been made to reduce the effect of other component forces, but they are not perfect.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a multi-component force detector capable of highly accurate and reproducible detection of up to 6 component forces without causing interference between measured component forces. The purpose is to provide.

[0004]

[Means for Solving the Problems]
Parallel to the measuring flange to which the force is applied.
Fixed flanges facing each other, fixedly connected to both flanges,
Formed with four flat plate beams with rectangular cross section,
The axis line passing through the center of both flanges is the Z axis,
The Z-axis and the intermediate surface extending parallel to both flanges in the middle of the
Introducing the Cartesian coordinate system X, Y, Z with the intersection as the origin,
One pair of beams has the short side of the rectangular cross section with respect to the ZX plane
Arranged symmetrically with respect to each other and symmetrical with respect to the YZ plane
And the other pair of beams YZ the short side of the rectangular cross section.
Faces the ZX plane at regular intervals.
Three sides are arranged symmetrically, excluding the short side surface on the Z-axis side of each beam.
Strain gauge attached near the measurement flange on the
And the strain gauge attached near the fixed flange is group B
The strain gauge attached to the positive side near Z = 0 as C group.
The strain gauge attached to the negative side near Z = 0 as D group
Whichever of the strain gauges belonging to the C group and the D group of both long side surfaces
Or stick one in the direction perpendicular to the Z-axis and
J is attached in the direction of the Z axis, and the component force F_x,F_yAgainst each buri
Edge circuit attached to the outer short side of the beam
Formed with 4 of the strain gauges of the group, the rotation moment M_X,
M_YAttach each bridge circuit to the outer short side of the beam
Formed with 4 sheets of strain gauges of C group and D group attached,
Component force F_zThe bridge circuit to the C group of the long side of the beam
And 16 groups of strain gauges of group D
To M _ZA bridge circuit for the group A on the long side of the beam
And component force detector formed by 16 strain gauges of group B
Has been achieved by

Other advantageous configurations are described in the dependent claims.

[0006]

[Operation] The force detector according to the present invention is
The measurement side flange and the fixed side flange facing each other
Connect and fix with the
Assuming a three-axis Cartesian coordinate system of X, Y, Z as the Z axis,
Component force F in each axis direction_x,F_y,F _ZAnd the rotation mode around each axis
Statement M_x,M_y,M_ZAll or part of the beam
Bridge circuit using strain gauges attached to each other
Maybe a force detector that detects independently, said beam
Z-axis on the measurement side flange and the fixed side flange
Place 4 or more on each axis on the X and Y axes around
However, the two main beams arranged on the X axis are
Strain gate with a rectangular cross section whose thickness is smaller than the length in the X-axis direction
The two beams placed on the Y axis have X
Square cross-section with axial thickness smaller than Y-axis length
It has a strain gauge sticking part of_xBridge to detect
The circuit consists of the above distortion distortion of two main beams arranged on the X axis.
F on the page attachment section_xTo be sensitive to bending stress due to
Structure including a strain gauge attached to the surface in the longitudinal direction.
Formed, component F_yThe bridge circuit for detecting is arranged on the Y-axis
At the strain gauge attachment part of the two main beams
F_yTo the bending direction due to
Consists of a strain gauge attached to the surface and a component force F_zInspect
The output bridge circuit is the distortion of each of the four main beams.
It is affixed to the gauge attachment part so that it is sensitive to direct stress.
Rotating momentum
To M_xThe bridge circuit that detects
Sensitive to direct stress at the gauge attachment part of the main beam of the book
It is configured to include the strain gauge attached so that it can rotate.
Moment M_yThe bridge circuit for detecting is placed on the X-axis
Directly at the gauge attachment part of the two main beams
Consists of a strain gauge attached to be sensitive to stress
And rotation moment M_z4 bridge circuits to detect
At the strain gauge attachment part of the main beam of_zby
Affixed to the surface in the thickness direction so that it is sensitive to bending moments.
It is configured to include a combination of strain gauges.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be specifically described below with reference to the accompanying drawings showing embodiments.

In a first embodiment of the invention, the main beam is 4
It will be described as a book. FIG. 1a shows a side view of a multi-component force detector according to a first embodiment of the present invention, and FIG.
A cross-sectional view of the line segment c-c is shown.

Here, 1 is a measurement side flange, 2 is a fixed side flange, and these flanges 1 and 2 are four at a distance L and are arranged symmetrically with respect to an axis (Z axis). The main beams (hereinafter simply referred to as beams) 3 to 6 are connected and fixed to each other. In this case, the cross-sections of these beams are rectangular, as shown in FIG. 1b, with the long sides B ₁ and the short sides T ₂ for the beams 3, 5 and the beams 4, 6 respectively. On the other hand, the long side is B ₂ and the short side is T ₁ , and the intervals between the two opposing beams 3 and 5 and 4 and 6 are L ₁ and L ₂ , respectively.

In the multi-component force detector having the above structure, the beam
X axis from 4 to beam 6, beam 3 from beam
Take the Y-axis in the direction of the frame 5 and move from the measurement side flange 1 to the fixed side.
The Z axis is taken in the direction of the flange 2. And each axis X, Y,
The component force in the Z direction is F _x,F_y,F_zAnd each axis X,
The rotational moments around Y and Z are M_x,M_y,M _z
And

When a component force F _y acts on the measuring side flange 1, the beams 3 and 5 are deformed as shown in FIG. 2a, and the beams 4 and 6 are deformed as shown in FIG. 2b. And each beam 3
The forces transmitted to 6 are proportionally divided in proportion to the spring constant with respect to the beam component force F _y .

[0012] Now, for simplicity of _{description, B 1 ≒ B 2, T} 1 when ≒ T _2, and _{L 1 ≒ L 2, B 1} »T 1, anti-beam 4,6 regard component force F _y Power can be ignored. The stress distribution generated by the component force F _y is shown in FIG.

FIG. 3b shows the stress distribution occurring at cross section 7-8, and FIG. 3c shows the stress distribution occurring at surface 7-9. As can be seen from these figures, the maximum bending stress due to the component force F _y occurs at the roots 7, 8, 9, 10 of the beam. Therefore, if the strain gauge is attached as close as possible to the base, the component force F _y can be detected efficiently.

With respect to the component force F _x , the same idea can be applied only by replacing the beams 3 and 5 in the case of the component force F _y with the beams 4 and 6 due to its symmetry.

Next, as shown in FIG. 4, the measuring flange 1
When a rotational moment M _x is applied to the beams 3 to 6, bending stress occurs in the beams 3 to 6 as shown in FIG. 4b. That is, the maximum bending stress σ _max occurs on the outer end faces 11-12, 13-14 of the beams 3, 5 in the Y-axis direction with respect to the rotation moment M _x . Therefore, the rotational moment M _x can be detected as the bending stress by attaching the strain gauges to the outer ends of the beams 3 and 5 at the same positions on the cross section perpendicular to the Z axis.

With respect to the rotation moment M _y , the same idea is established only by replacing the beams 3 and 5 with the beams 4 and 6 in the case of the rotation moment M _x .

Next, consider the case where the rotational moment M _z acts. Ignoring the twist of the beam, the result is as shown in FIG. FIG. 5a shows how the four beams are bent by using only one beam as a representative. Also, FIG. 5b shows the stress distribution in the cross section 15-16 of the beam root. From this FIG. 5b, if a strain gauge is attached to the base of the antinode of the beam, the rotation moment M _z can be effectively detected.

Further, when the component force F _z acts, the same stress is simultaneously generated in the four beams 3 to 6. Therefore, the component force F _z can also be detected separately from the other component forces F _x, F _y, M _x, M _{y, and} M _z .

From the above explanation of the stress distribution, the six-component force F _x, F
It is possible to detect _y, F _z, M _x, M _{y, and} M _z independently without interfering with each other.

Next, with reference to the above-mentioned stress distribution, an explanation will be given of a specific example of an advantageous method for attaching a strain gauge and a bridge connection circuit for eliminating mutual interference of component forces by these strain gauges.

FIGS. 6a and 6b are a schematic side view and a cross-sectional view, respectively, showing the strain gauge attachment position in the first embodiment of the present invention. Here, strain gauges that play the same role due to the Z-axis symmetry of the beams 3 to 6 are given the same reference symbols a to o,
Group as shown. That is, two strain gauges, preferably adjacent to each other, located at the center of the beam in the longitudinal direction on the short side of the beam cross section are marked with symbols a and b, and those affixed to the bases of both flanges 1 and 2 are labeled with c respectively. Turn it on. Also, two strain gauges, preferably adjacent to each other, located at the center in the longitudinal direction of the beam on one of the long sides of the beam cross section are marked with the reference signs F and G, respectively. And attach. In addition, the symbols "n" and "l" are attached to the ones at the center in the longitudinal direction of the beam on the other long side, and the symbols "l" and "e" are attached to the ones at the bases of the flanges 1 and 2. In this case, the strain gauges of the group corresponding to the codes F and N and the strain gauges of the group corresponding to the codes T and L are attached in the direction orthogonal to the Z axis, and all strains other than this one group are attached. The gauge is attached parallel to the Z axis.

Hereinafter, for convenience of explanation, it is assumed that the strain gauges of the groups corresponding to the symbols G and L are attached in the direction orthogonal to the Z axis.

7a to 7f, the component forces F _x, F _y, F _z, M _x, respectively formed by combining the strain gauges defined above are shown.
The connections of the bridge circuit for detecting M _{y and} M _z are shown.
Here, the positions of all the strain gauges are indicated by designating beams by reference numerals 4 to 6 and positions in the beam by reference numerals a to o.

FIG. 8 and FIG. 9 show the output of the bridge circuit for each component force and the output of the strain gauge alone used at that time. Here, + of the output indicates increase in resistance, − indicates decrease in resistance, and 0 indicates no change in resistance. The symbol A ~
M is the resistance change of each strain gauge that is not directly output to the bridge output end. Further, the symbol 1 indicates that there is a change in the bridge output, and 0 indicates that there is no change in the bridge output.

When the component force F _x acts, the stress shown in FIG. 3c is generated in the beams 3 and 5 of the F _z detecting gauge. Since the gauge is not in the center of the beam, the output of A is generated at the gauge and the output of B is generated at the gauge. However, at the output terminals of the F _z bridge, their outputs cancel each other out, so that no output change occurs. Further, Gejii beams 4,6, the resistance change of ± C occurs in Russia, M _x, the output change in the same way to the output terminal of the M _y bridge does not occur. Further, the strain gauges at the positions of the beams 3 and 5 undergo a resistance change of ± D, but no output change occurs at the output end of the M _z bridge.

Even when the component force F _y is acting, the same thing occurs due to the symmetry, and therefore detailed description will not be given.

When the component force F _z acts, the strain gauges constituting the F _x bridge and the F _y bridge undergo the resistance change E due to the same stress, but at the output end of each bridge, the resistance change E is caused. The outputs are canceled out, and the output does not change. However, the strain gauges of He and N in the F _z bridge have a direct stress, and the gauges of G and Le have a resistance change F in the opposite direction due to the Poisson's ratio. These resistance changes give an output change at the output end.

When the component force M _x acts, the resistance changes of ± G occur in C and D of beams 3 and 5, and
The output of ± H is generated in Nu and Oh,
Outputs of ± J are generated for F, J, L, N, and O, and ± K are output for T and L, but no output is generated for bridges other than M _x .

When the component force M _y acts, it is the same as when the component force M _x acts.

When the component force M _z acts, the
An output of ± L is generated at the output, and an output of ± M is generated at the output and the output.
_No output occurs on bridges other than _z .

In the above-mentioned embodiment, the 6-component force detector is shown, but it can be realized as a multi-component force detector in which some component forces in the 6-component force are collected. Further, the combination arrangement of the strain gauges may be changed, or 3-to-le for detecting the F _z component force may be used.
Instead of the Poisson's ratio output gauges of G and R, it is free to use a strain gauge attached to a portion where no strain appears as a dummy.

Further, it is possible to use only the gauges of the beams 3 and 5 for detecting M _z or to construct only the gauges of the beams 4 and 6 as a bridge.

10 to 12 schematically show another detector according to the present invention. All of these three types of detectors are configured by a plurality (two or three) of the pair of beams 3 and 5 shown in FIG. As for the sticking position of the strain gauge, the symbol α corresponds to a, b, c, and d in correspondence with FIG.
The symbol β corresponds to li, n, le, and o, and the symbol γ corresponds to e, h, to, and chi. Since the bridge connections of these strain gauges are the same as those in FIG. 7, further description will be omitted.

Using the rosette gauges, the strain gauges at the fist and le positions described with reference to FIGS. 6a and 6b and the strain gauges at the to and n positions attached adjacent to these strain gauges are
It can also be attached to the center of the beam.

As described above, various embodiments of the present invention can be constructed. It goes without saying that these configurations are within the scope of the present invention as long as they are the configurations defined in the claims.

[0036]

The advantages obtained by the multi-component force detector according to the present invention are high precision and good reproducibility even with a relatively simple structure, without interfering with each other for up to 6 types of component force. Can measure component force.

[Brief description of drawings]

FIG. 1 is a side view (a) of a multi-component force detector of a first embodiment according to the present invention and a cross-sectional view (b) taken along line cc.

2 is a side view schematically showing the deformation (a) of the beams 3 and 5 and the deformation (b) of the beams 4 and 6 when a component force F _x acts on the detector of FIG. 1. FIG.

FIG. 3 is a side view (a) showing local positions of beams 3 and 5 when a component force F _y is applied to the detector of FIG. 1, a schematic stress distribution diagram (b) and a surface 7 occurring in a cross section 7-8. It is a model stress distribution diagram (c) which arises in -9.

FIG. 4 is a schematic stress distribution diagram corresponding to a side view (a) showing local positions of the beams 3 and 5 when a component force M _y acts on the detector of FIG. 1.

FIG. 5 is a side view (a) and corresponding stress distribution diagram (b) showing the deformation of the beam (only one is shown due to symmetry) when a rotational moment M _z is applied.

FIG. 6 is a side view (a) and a cross-sectional view (b) showing an attachment position of a strain gauge.

FIG. 7 is a connection diagram (a to f) of a bridge circuit for detecting each component force.

FIG. 8 is a diagram showing an output of a bridge circuit corresponding to each component force.

9 is a diagram showing the output of the bridge circuit corresponding to each component force, and is a division diagram of FIG. 8.

FIG. 10 is a schematic sectional view showing a beam arrangement of a second embodiment.

FIG. 11 is a schematic cross-sectional view showing the beam arrangement of the third embodiment.

FIG. 12 is a schematic cross-sectional view showing the beam arrangement of the fourth embodiment.

[Explanation of symbols]

1 measuring flange 2 fixing flange 3-4 beam i ~ Oh strain gauge attaching position _{F x, F y, F z} , M x, M y, M z component force

Claims (5)

[Claims] 1. A measuring flange to which a force to be detected is applied,
It is formed by a fixed flange facing parallel to the measurement flange and four flat plate beams fixedly connected to the both flanges and having a rectangular cross section, and an axis line Z axis passing through the centers of the both flanges, and an intermediate point between the both flanges. Introducing a Cartesian coordinate system X, Y, Z whose origin is the intersection of the Z axis and the intermediate surface extending parallel to both flanges, and one pair of the beams has the short side of the rectangular cross section with respect to the ZX plane. The pair of beams are arranged symmetrically with respect to the YZ plane, and are arranged symmetrically with respect to the YZ plane. The other pair of the beams oppose the short sides of the rectangular cross section with respect to the YZ plane at regular intervals and are symmetrical with respect to the ZX plane. The strain gauges placed near the measurement flange on the three sides of the beams, excluding the short side surface on the Z-axis side, are group A, and the strain gauges attached near the fixed flange are group B. Strain gauge attached on the positive side near = 0 And the group, the strain gauge adhered to the negative side of the near Z = 0 and D group, both of any of the strain gauge belonging to group C and group D of the long side surface 1
One is attached in the direction perpendicular to the Z-axis, all other strain gauges are attached in the direction of the Z-axis, and each bridge circuit for component force F _x, F _y is attached to the outer short side of the beam. Formed with 4 of the strain gauges of the group, and formed with 4 of the strain gauges of the C and D groups in which each bridge circuit for the rotation moments M _X, M _Y is attached to the outer short side surface of the beam. , A bridge circuit for component force F _z is formed by 16 strain gauges of C group and D group on the long side of the beam, and a bridge circuit for rotational moment M _Z is formed of A group and B group of the long side of the beam. A multi-component force detector capable of measuring 6-component force, which is formed by 16 strain gauges and has a lever. 2. At least one pair of both beams is composed of an odd number of flat plate beams of three or more, and the strain gauge of the short side face is attached to the short side face of the central beam, and The force detector according to claim 1, wherein the strain gauges are attached to the corresponding long side surfaces of both lateral beams. 3. At least one pair of both beams are composed of two or more even-numbered flat plate beams, and the strain gauges on the short sides are connected in parallel with the strain gauges attached to the short sides of both beams. The force detector according to claim 1, wherein the strain gauges on the long side faces are attached to the corresponding long side faces of both beams. 4. The two sets of strain gauges of the C group and the D group attached to the long side surface are each constituted by one rosette, and are attached at Z = 0. The force detector according to any one of claims 1. 5. The six-component force detector defined in any one of claims 1 to 4, wherein the component forces F _x, F _y, F _Z, M _x, M _y, M _Z.
Among them, a multi-component force detector characterized by forming a bridge circuit of only the necessary component force and measuring only the component force.