JPH10332417A - Contact-type sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact-type range-finding sensor that is free from breakage an can carry out an accurate measurement. SOLUTION: The contact-type range-finding sensor comprises shape memory alloy shafts 40a and 40b which come in contact with an object to be measured, a shaft holder 5 connected to the shape memory alloy shafts 40a and 40b, and a potentiometer 1 for measuring a rotation amount of the shaft holder 5. When a force except for a rotation direction 'D' of the shape memory alloy shaft 40a and 40b is applied to the shape memory alloy shaft 40a and 40b, the shape memory alloy shaft 40a and 40b is elastically deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type sensor, and more particularly to a contact type sensor provided with a member which rotates around an axis by being brought into contact with an object to be measured, and measuring a degree of the rotation.

[0002]

2. Description of the Related Art FIG. 11 is a perspective view of a robot 15 using contact type distance measuring sensors 17a to 17d according to the prior art. The robot 15 includes contact-type distance measuring sensors 17a to 17a.
By using 7d, the distance to the left and right walls is measured, and the vehicle follows the wall. The working unit 16 includes a brush driven by a motor, and performs a cleaning operation on the floor surface.

FIG. 12 is a perspective view showing one configuration of contact type distance measuring sensors 17a to 17d provided in a robot, and FIG. 13 is a side view thereof. FIG. 12 and FIG.
3, the contact-type distance measuring sensor includes a contact roller 35 that contacts a measurement target such as a wall, a contact roller shaft 36 for rotating the contact roller 35, and one end connected to the contact roller shaft 36. Shaft 4, a potentiometer 1 for detecting the angle of rotation of the shaft 4, and a potentiometer 1
A shaft holder 5 for connecting the rotary shaft 22 to the shaft 4, a sensor base plate 2 connected to the potentiometer 1 and used for mounting the contact-type distance measuring sensor to the robot 15, and formed integrally with the sensor base plate 2. Base plate nail 3
By interposing the shaft center positioning pawl 6 integrally formed on the shaft holder 5, the base plate pawl 3 and the shaft center positioning pawl 6 at both ends thereof, the shaft 4 is moved toward the neutral position of the shaft 4. And a torsion coil spring 7 for applying an urging force.

[0004] The shaft 4 is rotatable clockwise or counterclockwise by a predetermined angle around a rotation shaft 22 of the potentiometer 1. Thus, the shaft 4 rotates in a predetermined plane.

When the object to be measured comes into contact with the shaft 4 or the contact rollers 35, the shaft 4 rotates in a predetermined plane. The biasing force provided by the spring 7 returns the shaft 4 to the neutral position.

Further, since the contact roller 35 freely rotates about the contact roller shaft 36, when the robot 15 travels along the left and right walls, the contact roller 35 and the wall or the like to be measured are moved between the robot 15 and the wall. Friction generated between them can be reduced.

FIG. 14 is a plan view for explaining the operation of the contact distance measuring sensor shown in FIGS.

FIG. 14 (a) shows a neutral state of the shaft 4, and FIG. 14 (b) shows that the shaft 4 has moved in a predetermined plane by the contact of the measuring object 9 with the contact rollers 35. The state is shown.

In FIG. 14B, the shaft 4
Has rotated counterclockwise from the state shown in FIG. 14A, but can also rotate clockwise.

When the object 9 comes into contact with the contact rollers 35 from the state shown in FIG. 14A, the shaft 4 is turned around the rotation shaft 22 with respect to the drawing as shown in FIG. Rotate clockwise. In the state shown in FIG. 14B, the torsion coil spring 7 urges the shaft 4 via the shaft holder 5 with a force in the clockwise direction around the rotation shaft 22. Here, assuming that the angle (rotation angle) at which the shaft 4 rotates from the neutral state is A, the length of the shaft 4 is L, and the radius of the contact roller 35 is r, the distance from the rotation shaft 22 of the potentiometer to the object 9 to be measured. d is represented by equation (1).

D = r + L × cosA (1) Thus, the distance between the contact distance measuring sensor and the object to be measured is calculated.

FIG. 15 is a plan view for explaining the operation of the robot shown in FIG. In FIG. 15, the robot 15 is performing autonomous movement along the left wall surface 18 in the traveling direction “X”. In this state, the contact-type distance measuring sensors 17c and 17d provided on the left side with respect to the traveling direction "X" come into contact with the wall surface 18 so that the shaft rotates counterclockwise from the neutral state with respect to the drawing. ing. The rotation angle of the shaft is detected by a potentiometer, whereby the distance between the robot 15 and the wall surface 18 is detected. Based on the detected distance, the robot 15 travels along the wall surface 18, and the working unit 16 is controlled to follow the wall surface 18.

The robot 15 operates as described below so that the robot 15 can perform operations such as cleaning to all corners of the wall.

When the robot moves away from the wall 18 in the movement direction "X" as shown in FIG. 16, and also in the movement direction "X" as shown in FIG.
Even when the robot approaches the wall surface 18, the wall-side end of the working unit 16 is positioned on a straight line 24 connecting the contact rollers of the contact-type distance measuring sensor 17c and the contact-type distance measuring sensor 17d, The operation of the working unit 16 is controlled. This allows
You can always work to every corner.

Such control is performed by the contact type distance measuring sensor 17.
The measurement is performed by measuring the rotation angles of the shafts c and the contact type distance measuring sensor 17d with a potentiometer.

[0016]

However, the conventional contact-type distance measuring sensor has the following problems.

The contact-type distance measuring sensor detects the distance between the sensor and the object to be measured by bringing the contact rollers 35 into contact with the object to be measured. When the distance measuring sensor is mounted, it is necessary to mount the shaft 4 and the contact rollers 35 so as to protrude from the main body of the moving body.

As shown in FIG. 18, a force "Z" acting in a direction parallel to the rotating shaft 22 of the potentiometer 1 is applied to the shaft 4 and the contact rollers 35 of the contact type distance measuring sensor thus mounted. In some cases, the shaft 4 and the engaging portion between the shaft 4 and the potentiometer 1 may be damaged.

In order to solve such a problem of damage, it is conceivable to construct a contact-type distance measuring sensor as shown in a perspective view of FIG. In FIG. 19, the rod-shaped shaft 4 in FIG. 12 is replaced with a shaft 10 constituted by a spring.

FIG. 20 is a side view of the contact-type distance measuring sensor configured as described above. As shown in FIG. 21, a force "Z" acting in a direction parallel to the rotation shaft 22 is applied. The shaft 10 constituted by a spring
Is bent, it is possible to prevent the contact type distance measuring sensor from being damaged.

However, the contact-type distance measuring sensor configured as described above has a problem as shown in FIG. That is, when the robot is traveling in the traveling direction “A”, the measurement object 9 whose distance is to be measured is
Is in contact with only a part of the contact roller 35, the spring is easily twisted in the direction indicated by "C", so that the contact roller 35 is moved in the direction "B" by the contact friction between the measurement object and the contact roller. It rotates around a shaft 10 constituted by a spring. In such a state, normal measurement by the potentiometer 1 cannot be performed.

In order to solve the problem of breakage shown in FIG. 18, a fulcrum 13 shown in FIG.
It is also conceivable to provide a positioning coil spring 14. That is, as shown in FIG. 24, when an external force “Z” is applied, the shaft 4 is bent at the fulcrum 13. Thereby, breakage of the contact-type distance measuring sensor can be prevented.

However, even in the contact-type distance measuring sensor configured as described above, an unreasonable torsion force as shown in FIG. 22C may be applied due to an accident during transportation or the like. At this time, the contact distance measuring sensor may be damaged.

The present invention has been made in order to solve the above-mentioned problems, and has as its object to provide a contact-type sensor capable of performing accurate measurement without causing a problem of breakage.

[0025]

According to one aspect of the present invention, a contact-type sensor includes a member that rotates around an axis by contacting an object to be measured, and a degree of rotation of the member. , Wherein at least a part of the member includes a shape memory alloy.

According to the present invention, it is possible to provide a contact-type sensor capable of performing accurate measurement without causing a problem of breakage.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIG. 1 is a perspective view of a contact-type distance measuring sensor according to a first embodiment of the present invention, and FIG. 2 is a side view thereof.

Referring to the drawing, a potentiometer 1, a sensor base plate 2, a base plate pawl 3, a shaft center positioning pawl 6, a torsion coil spring 7,
The point provided with rotary shaft 22 is the same as that of contact-type distance measuring sensor in FIG. 12, and therefore description thereof will not be repeated.

In the contact distance measuring sensor shown in FIG.
Shape memory alloy shafts 40 a and 40 b made of a wire-shaped shape memory alloy are connected to the shaft holder 5. The shape memory alloy shafts 40a and 40b are independently attached to the shaft holder 5.

The shape memory alloy shaft 40a
It has a shape bent at 0 °, and further has a shape whose tip is bent toward the shaft holder 5 side. The shape memory alloy shaft 40b has a shape bent 90 ° downward,
Further, the tip has a shape bent toward the shaft holder 5. When the object to be measured comes into contact with one or both of the shape memory alloy shafts 40a and 40b, the shape memory alloy shafts 40a and 40b are pointed by the arrow "D".
Rotate in the direction. The amount of this rotation is measured by the potentiometer 1.

A superelastic alloy is used as the shape memory alloy constituting the shape memory alloy shafts 40a and 40b.
The shape memory alloy has a transformation point peculiar to the material, that is, a shape recovery temperature at which the shape returns to its original shape when the temperature exceeds a certain temperature even after plastic deformation. A superelastic alloy has a very low shape recovery temperature. When a superelastic alloy is used at room temperature, it is always used at a temperature equal to or higher than the shape recovery temperature, and has a very high elasticity. Superelastic alloys are also resistant to breakage due to torsion.

Therefore, the shape memory alloy shaft 40
Even if a large force is applied to a and 40b from directions other than the rotation direction, the contact-type distance measuring sensor is not damaged. For example, as shown in FIG. 3, when an external force is applied in the “Z” direction, the shape-memory alloy shaft 40a curves downward, so that the contact-type distance measuring sensor is not damaged.
When no force is applied, the shape memory alloy shaft 40a returns to its original shape.

Further, the shape memory alloy shafts 40a, 40
b is not easily twisted like a spring as shown in FIG. In addition, breakage due to twisting is prevented.

Further, the shape memory alloy shafts 40a, 4
Since 0b can be formed into a wire, the shaft can be reduced in weight. As a result, the inertial force during the movement of the shaft can be reduced, and the response of detection is improved. Further, grooves for projecting the shape memory alloy shafts 40a and 40b from the robot main body (FIG. 1)
1), the dustproof effect is improved.

Further, the configuration of the contact distance measuring sensor can be simplified, and the cost of the sensor can be reduced.

The shape memory alloy shafts 40a, 40
b is an L-shaped shape memory alloy shaft 4 without bending the tip to the shaft holder 5 side as shown in FIG.
1a and 41b may be used. However, as shown in FIG. 4, when the upper portion of the measurement target 9 is obliquely overhang, the shape memory alloy shaft 41a may be caught. On the other hand, as shown in FIG. 5, by bending the tips of the shape memory alloy shafts 40a and 40b toward the shaft holder 5 as in the present embodiment, the measurement object 9 and the shape memory alloy shafts 40a and 40
0b can be prevented from being caught.

[Second Embodiment] FIG. 6 is a perspective view showing the configuration of a contact distance measuring sensor according to a second embodiment of the present invention. Referring to the figure, in the present embodiment, tubes 42a and 42b made of a flexible and easy-to-slip material such as Teflon are fitted to portions of shape memory alloy shafts 40a and 40b that come into contact with the object to be measured. Alternatively, Teflon tape or the like may be wound).

By configuring the contact-type distance measuring sensor in this way, in addition to the effect of the first embodiment, the friction when the shape memory alloy shafts 40a and 40b contact the object to be measured is reduced. And the shape memory alloy shafts 40a, 4
0b can be easily rotated.

Further, friction when moving while contacting can be reduced. Furthermore, it is possible to prevent the measurement target from being damaged, and to eliminate unpleasant noises between the metals, particularly when the measurement target is a metal.

Further, the shape memory alloy shafts 40a, 4
0b and the object to be measured are likely to slip,
It is possible to more effectively prevent an excessive force from being applied to the contact-type distance measuring sensor.

In the first and second embodiments, a contact roller 35 and a contact roller shaft 36 as shown in FIG. 12 may be provided.

[Third Embodiment] FIG. 7 is a perspective view of a microswitch 50 (contact type sensor) according to a third embodiment of the present invention, and FIG. 8 is a side view thereof.

Referring to the figure, micro switch 50 is
A detection switch 52 that is turned on when pressed down, a shape memory alloy wire 51 for pressing down the detection switch 52 by contacting an object, and a shape memory alloy wire 51
And a lead wire 54 for transmitting an ON / OFF signal by the detection switch 52.

In the micro switch according to the present embodiment, the wire 51 for pressing the detection switch 52 is made of a shape memory alloy, so that a force is applied in the direction of the arrow as shown in FIG. Even when a large force is applied to the wire 51 after the button is pressed, the shape memory alloy wire 51 is deformed, so that the microswitch 50 can be prevented from being damaged. That is, the stroke after the detection switch 52 is turned on can be lengthened, and the microswitch 50 can be applied to more situations.

[Fourth Embodiment] FIG. 9 is a perspective view showing the configuration of a contact sensor according to a fourth embodiment of the present invention.

Referring to the figure, the contact sensor comprises a rod-shaped contact member 55 made of a shape memory alloy, and strain gauges 56a and 56b for detecting the strain of the contact member 55. The strain gauges 56a and 56b are provided so as to be shifted from the center by 90 ° in the cross section of the contact member 55.

For example, when a force is applied to the contact member 55 in the direction of the arrow, when the contact member 55 is deformed into the shape indicated by the dotted line, the strain generated at that time is measured by the strain gauge 56.
a and 56b are detected. As described above, the strain gauge 56a,
Since the members 56b are provided at intervals of 90 °, it is possible to detect in which direction the contact member 55 is bent and how much the contact member 55 is bent.

Although the number of strain gauges is two in this embodiment, it may be more than two.

[Fifth Embodiment] FIG. 10 is a perspective view of a joystick 60 according to a fifth embodiment of the present invention.

Referring to the figure, joystick 60 has a shaft 61 made of a shape memory alloy. The shape memory alloy according to this embodiment has a high strength, and is configured such that the shaft 61 is deformed when an excessive force is applied by operating the joystick 60. This can prevent the joystick 60 from being damaged.

[Brief description of the drawings]

FIG. 1 is a perspective view of a contact-type distance measuring sensor according to a first embodiment of the present invention.

FIG. 2 is a side view of the contact-type distance measuring sensor of FIG.

FIG. 3 is a diagram illustrating a state where an external force in a “Z” direction is applied in the state of FIG. 2;

FIG. 4 is a side view showing a modified example of the sensor of FIG.

FIG. 5 is a diagram for explaining an effect in the first embodiment.

FIG. 6 is a perspective view of a contact-type distance measuring sensor according to a second embodiment of the present invention.

FIG. 7 is a perspective view of a micro switch according to a third embodiment of the present invention.

FIG. 8 is a side view of the microswitch of FIG. 7;

FIG. 9 is a perspective view of a contact sensor according to a fourth embodiment of the present invention.

FIG. 10 is a perspective view of a joystick according to a fifth embodiment of the present invention.

FIG. 11 is a perspective view of a robot including a contact-type distance measuring sensor according to a conventional technique.

FIG. 12 is a perspective view of a contact-type distance measuring sensor provided in the robot of FIG. 11;

FIG. 13 is a side view of the contact distance measuring sensor of FIG.

FIG. 14 is a diagram for explaining the operation principle of the sensor of FIG.

FIG. 15 is a first diagram for explaining the operation of the robot in FIG. 11;

FIG. 16 is a second diagram illustrating the operation of the robot in FIG. 11;

FIG. 17 is a third diagram for explaining the operation of the robot in FIG. 11;

FIG. 18 is a side view for explaining a problem of the contact distance measuring sensor of FIG. 12;

FIG. 19 is a perspective view of a contact distance measuring sensor using a spring for a shaft.

FIG. 20 is a side view of the contact-type distance measuring sensor of FIG. 19;

FIG. 21 is a diagram for explaining a state in which a force is applied in the “Z” direction from the state of FIG. 20;

FIG. 22 is a view for explaining a problem of the sensor shown in FIG. 19;

FIG. 23 is a side view of a contact type distance measuring sensor in which a coil spring 14 is provided on a shaft.

FIG. 24 is a diagram showing a state where a force is applied in the “Z” direction from the state of FIG. 23;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Potentiometer 5 Shaft holder 40a, 40b Shape memory alloy shaft 42a, 42b Teflon tube

Claims (1)

[Claims] 1. A contact-type sensor that includes a member that rotates around an axis by being in contact with an object to be measured and that measures a degree of rotation, wherein at least a part of the member includes a shape memory alloy. Characteristic, contact type sensor.