JPS60177233A - Multiple force component detector - Google Patents

Abstract

PURPOSE:To realize a titled small-sized, inexpensive multiple force component detector by arranging a disk body and an annular body concentrically, and arranging plural position sensors which detect their relative displacement at the outer periphery of the disk body and the inner periphery of the annular body. CONSTITUTION:The disk 4 is provided with four image sensors 5 (5a,...), the ring 9 is four light emission bodies 10 (10a,...), and leaf springs 6 (6a,...) are arranged between the disk 4 and ring 9. Centers of facing surfaces of the sensors 6 and light emission bodies 10 are denoted as A and B; and X-axial distance between points A and B is denoted as (p) and Y-axial distance is represented as (q). Then, output characteristics obtained by processing outputs of the sensors 5 show that the distances (p) and (q) are in specific relation, so the outputs of the sensors are measured to detect displacement in each direction and force proportional to the displacement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a small and inexpensive multi-force detector.

[Prior art]

In complex structures such as industrial robots, multi-force detectors are used to simultaneously and accurately detect the complex force and moment exerted on each joint, etc. Conventionally, strain gauges and Some devices use piezoelectric elements, but they are both expensive and large, so they cannot be used in small robots such as tabletop robots.

[Summary of the invention]

In order to solve these drawbacks, this invention combines a plurality of position sensors and detects the forces acting in each direction based on changes in their relative positions. It is possible to realize an inexpensive multi-force detector. Hereinafter, this invention will be explained with reference to the drawings.

[Embodiments of the invention]

FIG. 1 is an embodiment of the present invention, and shows the external appearance of a multi-force detector. In this figure, reference numeral 1 denotes a housing, which has a cylindrical shape and is provided with a busy shaft 2 coaxial with the shaft of the cylinder. In this specification, the fine direction of the axis 2 in FIG. 1 is defined as two axes, and the orthogonal directions on the clove surface that are perpendicular to this are defined as the X axis and the y axis. The shaft 2 is movable in the radial and circumferential directions with respect to the housing 1, and when the axis of the shaft 2 is set as two axes, the ziil
n moments around l) M, and force F in the X-axis direction,
) When a force F in the r-axis direction acts on the shaft 2, the structure is such that an output corresponding to the force F is outputted from the signal #3.

FIG. 2 shows an exploded view of the multi-force detector shown in FIG. 1.

Axis 2KG! A disk 4 is fixed, and four VC images are arranged at equal intervals on the circumference of the disk 4.
50. 5 d (hereinafter collectively referred to as 5. The same applies to other symbols) and leaf springs 6a, 6b,
6c and 6d are fixed on the inside. Further, on the upper surface of the disk 4, there is a plate made of a material with a small coefficient of friction, such as a fluororesin plate 7, which easily slides between it and the upper plate B. A ring 9 having approximately the same thickness as the disk 4 is placed on the outside of the disk 4, and the outside of the leaf springs 68 to 6d are fixed to the inside of the ring 9, so that the ring 9 and the disk 4 have a concentric structure. ing. Furthermore, inside the ring 9, there are light emitters 10a and 10b.
, 10c, and 10d are provided at equal intervals and face the image sensors 5a to 5d. There is a lower plate 11 below the ring 9, and on the upper surface of the lower plate 11 there is a material with a small coefficient of friction, such as a fluororesin plate 12, so that the disk 4 can easily slide against the lower plate 11.

As mentioned above, the disk 4 is restrained by the upper plate 8 and the lower plate 11Vc via the fluororesin plates 7 and 12, and around 2
And it is movable only in the x and X axis directions. Also,
Around two axes and xy due to the action of leaf springs 68 to 6d
It is configured to have a displacement proportional to the axial force. As shown in FIG. 3, the light emitter 10 includes a light emitting element 13. It consists of a slint 14° and a case 15, and is configured to emit parallel +16.

FIG. 4 is a sectional view taken in a plane perpendicular to the two axes. Image sensors 5a-5d, light emitters 10a-10dl leaf springs 6a-
The positional relationship of 6d is shown more clearly. Leaf spring 6&
~6d has the role of producing a displacement proportional to the force as mentioned above, and is not limited to the plate spring (disc 4 and ring 9).
It may be an elastic material such as a high or molecular material that fills the space between zero.

Next, the principle by which force can be detected with such a configuration will be explained.

FIG. 5 shows the image sensor 5 and the light emitter 1o facing each other. The center of the facing faces of j is A,
When B, the distance between points A and B in the X-axis direction is p, y
Let the distance in the axial direction be q.

The light emitted from the light emitter 10 enters the image sensor 5,
The output of the image sensor 5 enters the arithmetic circuit 17, and is subjected to necessary arithmetic processing based on the distance position of the image sensor 5, etc., and its output characteristics are as shown by the caustic line in Fig. 6. The characteristic is proportional to the distance p in the X-axis direction. This output characteristic is determined by the distance qici! in the y-axis direction. is hardly dependent.

This output characteristic V2αP In Table 1, α is a constant.

FIG. 7 shows a steady state after moving by δ in the θ direction from the reference position shown in FIG.

In this state, there is a lateral shift of the opposing surfaces of the image sensors 5a to 5d and the light emitters 10a to IQd.
t (corresponding to the amount of movement in the X-axis direction in FIG. 5, that is, the distance pK) is p+ at the image sensor 5a, p2+5c at 5bVc, p4 at 5'Cp3°, and p4 at 5d.
If we put, p+”δe08θ1p2−δaimθ1p3=δcos
θ.

Since p4-δsimθ, the outputs of the image sensors 5a to 5d after calculation are respectively ■, =-αδeollθ, v, =-αδainθIV,
--αδcoIIθ, ■4−αδsinθ.

FIG. 8 shows a case where the reference position shown in FIG. 4 has been rotated by θ', and in this case, if r is the radius of the disk 4, then V; =v; =V', = v: = α r a in
f) 'xct r fl'.

If both are mixed, it will be the sum, and each output will be E+ = Vr
+V'+, Ex = Vs +V'z.

E J ='Vs +V'j, E4 ``V4+V'<.

By using these outputs and performing calculations using appropriate well-known calculation means, displacement in each direction can be detected.

Rotation direction E, = E + +E x + E s
+B 4 = 4αrθ′y-axis direction E, =E4 E
2”2αδainθX-axis direction E X = E B E
1=2αδcotθ, that is, θ′2E,/4αr 6=ToheiF■ 2α′FJx θ=jan′−E.

Accordingly, the displacement of j and r can be detected. After all, since the displacement is proportional to the force acting in that direction.

This means that the magnitude and direction of force can be detected.

In the above description, the light emitter 10 is arranged on the ring 9 and the image sensor 5 is arranged on the disk 4, but it is obvious from the principle that an inverted n arrangement is also possible. Furthermore, the combination of the light emitting body 10 and the image sensor 5 is not limited;
Any position sensor that can obtain the characteristics shown in FIG. 6 can be applied to the present invention.

Further, in the above embodiment, the disk 4 and ring 9 are used, but generally any disk body may be used. Similarly, the ring 9 may also be of another shape (or an annular body). However, it is not necessary to arrange the plurality of position sensors at equal intervals, and even if they are arranged at irregular intervals, correction may be made to prevent false alarms. Yes.

〔Effect of the invention〕

As explained above, this invention supports a disc body concentrically within an annular body with an elastic body that generates displacement in proportion to force, and between the outer periphery of the disc body and the inner periphery of the annular body. It is possible to detect the relative position between the annular body and the disc body by installing multiple position sensors on the body, and to simultaneously detect and combine the forces that act in multiple directions due to changes in the position, which is inexpensive and yet effective. There is an advantage that a compact multi-force detector can be realized.

[Brief explanation of the drawing]

Fig. 1 is an external view of one embodiment of the present invention, Fig. 2 is an exploded perspective view showing its internal structure, Fig. 3 is a side sectional view showing details of the light emitting body, and Fig. 4 is the same as that shown in Fig. 1. FIG. 5 is a plan cross-sectional view of the embodiment of 1, which explains the positional relationship between the light emitting body and the image sensor.
Figure 6 is the output characteristic diagram of the image sensor, Figure 7 is the output characteristic diagram of the image sensor.
8 and 8 are diagrams for explaining the relative displacement between the ring-shaped body and the disk, respectively. In the figure, 1 is a housing, 2 is a shaft, 3 is a signal line, 4 is a disk, 5 is an image sensor, 6 is a leaf spring, 7 and 12 are fluororesin plates,
8 is an upper plate, 9 is a ring, 10 is a light emitter, 11 is a lower plate, 13 is a light emitting element, 14i is a slit, 15 is a case,
16 is parallel light, and 17 is an arithmetic circuit. Figure 1 Figure 2 Figure 3 Throw Figure 4 Figure 5] Figure 6

Claims (1)

[Claims] An elastic body that produces a concentric displacement in proportion to force in an annular disc-shaped body around two axes and the X-axis. A plurality of position sensors are disposed so as to be displaceable in the X-axis direction, and are arranged to face each other between the outer circumference of the disk body and the inner circumference of the annular body and detect relative displacement between the disk body and the annular body. A multi-force detector featuring: