JPH0775630A - Joint angle sensor - Google Patents

Abstract

PURPOSE:To provide the finger joint angle sensor which has high durability and does not render a testee a restraining feel. CONSTITUTION:A magnet 1 is arranged on a fingertip 4a side and a magneto-electic conversion element 2 is arranged on a finger root 4b side on the same straight line as a turning direction while holding a joint back side 5a therebetween by averting the expanding and contracting skin part on the joint back side 5a in an angle detecting section. A change in the relative positions between the magneto-electic conversion element 2 and the magnet 1 on a turning plane arises according to turning of the finger 4. The bending angle of the joint 5 is detected by changing of the magnetic field near the magneto-electic conversion element 2. The output of the magneto-electic conversion element 2 is amplified by a signal processing circuit and the voltage corresponding to the bending angle of the joint is outputted. The principle of this sensor is not to detect the stress arising from turning of the operating part but to measure the change in the circumferential length and the change in the relative position of the angle without contact and, therefore, the device parts do not exist on the expanding and contracting part of the joint and do not hinder turning. Since the sensor is constituted not to apply a physical stress on the device itself, the durability of the repetitive use of the device is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting bending of a joint of a body.

[0002]

2. Description of the Related Art As a joint angle sensor which has been conventionally used, a glove shown in U.S. Pat. No. 4,542,291 is equipped with an optical fiber cable to detect leak loss due to bending of the cable, and Kaihei 1-
Some of them have a resistance value that changes due to expansion and contraction of the conductive rubber as seen in 136632, and some of which use the electrical output of a strain gauge as seen in Japanese Patent Laid-Open No. 4-12201.

[0003]

In the conventional joint angle sensor as described above, since the bending portion is provided above or below the measurement portion, the bending movement of the joint is limited, and the natural and rapid movement cannot be detected. In addition, the flexion of the joint is stressed and the user suffers. In addition, since the bent portion of the device is fatigued by repeated bending, the durability was not good.

The present invention eliminates these problems of the prior art and provides a joint angle sensor that is smaller, lighter and cheaper.

[0005]

A joint angle sensor according to the present invention comprises a magnet that forms a magnetic field in the vicinity of a joint and a detecting section that detects the magnetic field. The magnet and the detecting section include:
It is configured by providing a fixing portion for mounting at a position facing each other around the working portion of the joint.

[0006]

With the above-described structure, when the relative position of the magnetoelectric conversion element and the magnet on the rotation plane changes due to the rotation of the finger joint, for example, the magnetic field near the element changes. The bending angle of the finger is detected by. In other words, unlike the conventional example, it does not detect the stress accompanying the rotation of the finger in principle, but measures the circumference change and the relative position change of the angle in a non-contact manner. Since there are no device parts and it does not hinder the rotation of the finger, and because the configuration can be extremely simplified, it is small and lightweight, and the user does not feel discomfort at the time of wearing. Moreover,
It can be provided at low cost.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A joint angle sensor according to a first embodiment of the present invention will be described with reference to FIGS. In the figure, 1 indicates a magnet made of, for example, a permanent magnet. The magnet 1 is a ring made of rubber having appropriate elasticity or a cloth band member used for a sports supporter or the like so that the magnet 1 can be inserted and fixed to the fingertip 4a side around the operation part of the joint back 5a. The first fixing portion 6 having a shape of a circle is provided. Therefore,
The magnet 1 is fixed by the first fixing portion 6 to the fingertip 4a side centering on the operating portion near the joint portion 5a, and forms a magnetic field around the joint 5 near the operating portion. Reference numeral 2 in the figure denotes a magnetoelectric conversion element that converts magnetic energy into electric energy. The magnetoelectric conversion element 2 is provided with a second fixing portion 7 similar to the first fixing portion 6 by an appropriate method so that it can be inserted and fixed to the finger root 4b side around the motion portion of the joint back portion 5a. ing. Therefore, the magnetoelectric conversion element 2 is fixed by the second fixing portion 7 on the side of the finger root 4b centering on the operating portion near the joint portion 5a, and the strength of the magnetic field formed by the magnet 1 is detected. As a result, the magnet 1 and the magnetoelectric conversion element 2 are attached at opposing positions centering on the operating part of the joint 5. The first fixing portion 6 and the second fixing portion 7 may be formed by providing a double-sided adhesive tape or adhesive on the joint 5 mounting surface of the magnet 1 or the magnetoelectric conversion element 2. At this time, the magnet 1 and the magnetoelectric conversion element 2
It is desirable to set the distance between them to 10 to 20 mm.
A cord 3 including, for example, a power supply line and a signal line is output from the magnetoelectric conversion element 2 and is connected to the signal processing circuit 10.

FIG. 2 is an explanatory view of the magnetoelectric conversion element 2.
The magnetoelectric conversion element is a sensor that uses the Hall effect in which the resistance value changes with changes in the magnetic field. The magnetoelectric conversion element 2 used in this embodiment has sensitivity in the x-axis direction and the y-axis direction, and A positive voltage is generated for the N pole and a negative voltage is generated for the S pole. For example, when the N pole of the magnet 1 is arranged toward the magnetoelectric conversion element 2, the magnetoelectric conversion element 2 generates a positive voltage according to the relative position change such as the angle θ due to the bending of the joint and the change in the circumferential length in the y-axis direction. To do. Also, by fixing the x-axis direction so that it is orthogonal to the mounting surface (radial direction),
It is possible to increase the sensitivity when the bending angle θ at the time of rotation is large. In our experiment, detection was sufficiently possible even if the x-axis direction was fixed parallel to the mounting surface (tangential direction).

FIG. 3 shows a signal processing circuit 10 for amplifying the output of the magnetoelectric conversion element 2. The output from the magnetoelectric conversion element 2 is the signal processing circuit 1 that is composed of one operational amplifier 8.
It is amplified through 0. The signal processing circuit 10 performs amplification according to the following equation, and the zero point can be easily adjusted by adjusting the variable resistor 9. Therefore, after fixing the magnet 1 and the magnetoelectric conversion element 2 to the finger 4, the zero point can be set at a predetermined relative position.

[Equation 1]

FIG. 4 is an example of an output graph for the bending angle of the finger joint through the signal processing circuit 10. In this embodiment, the maximum output is 5V when the knuckle is extended, and the minimum output is 0V when the knuckle is fully rotated. Although there is no linearity, there is almost no hysteresis, and stable output can be obtained according to the bending of the joint.

FIG. 5 shows a basic configuration diagram of the second embodiment according to the present invention. The description of the same reference numerals as in the first embodiment will be omitted here. The magnet 1 and the magnetoelectric conversion element 2 are arranged with respect to an arbitrary joint 5 of the finger 4, but the magnet 1 and the magnetoelectric conversion element 2 similar to those described in the first embodiment keep the distance between them constant, and It is fixed to 11 by an appropriate means. The base material 11 is, for example, a rubber-made member having appropriate elasticity so as not to be displaced with respect to the movement of the finger 4 or a cloth band member used for sports supporters or the like, and fits on the finger 4. So that the first fixed part 1
It is formed from 1a and the 2nd fixed part 11b. Further, holes 12a and 12b that do not hinder the rotation of the finger 4 are provided on both surfaces of the joint dorsal side 5a and the abdominal side 5b corresponding to the joint 5, and at the same time, the magnet 1 and the magnetoelectric conversion element 2 are almost not attached at the time of wearing. The connecting portion 13 is provided so as to maintain a constant distance.
The magnet 1 is arranged on the side of the fingertip 4a on the straight line in the rotation direction of the finger 4 with the hole 12a of the base material 11 interposed therebetween, and the magnetoelectric conversion element 2 is arranged on the side of the finger root 4b. At this time, the magnet 1 and the magnetoelectric conversion element 2 may be fixed with a double-sided adhesive tape, or may be embedded in the base material 11. A code 3 is output from the magnetoelectric conversion element 2 and is connected to the signal processing circuit 10.

By using the base material 11 having the holes 12a and 12b and the connecting portion 13 as described above, the joint 5
It is possible to always keep the distance between the magnet 1 and the magnetoelectric conversion element 2 constant without hindering the bending, and it is easy to attach and detach the detector.

A basic configuration diagram of the third embodiment according to the present invention is shown in FIG. The description of the same reference numerals as in the first embodiment will be omitted here. The magnet 1 and the magnetoelectric conversion element 2 are arranged with respect to an arbitrary joint 5 of the finger 4. At this time, the base material 11 is used to keep the distance between the magnet 1 and the magnetoelectric conversion element 2 constant. Further, when the joint skeleton is large and the distance between the magnet 1 and the magnetoelectric conversion element 2 cannot be kept optimal when the magnet 1 and the magnetoelectric conversion element 2 are mounted on the finger, the magnet 1 and the magnetoelectric conversion element 2
Beams 14a and 14b having sufficient strength for holding the beam 1 are arranged on both sides of the hole 12a of the base material 11, and the beam 1 on the fingertip 4a side.
The magnet 1 is fixed to 4a and the magnetoelectric conversion element 2 is fixed to the beam 14b on the side of the finger root 4b, for example, or fixed by a double-sided adhesive tape.

As described above, by providing the beam 14, the distance between the magnet 1 and the magnetoelectric conversion element 2 can always be kept constant even when the hole 12a of the base material 11 is large.

[0015]

As described above, according to the present invention,
Uses a magnet and a magnetoelectric conversion element to efficiently detect changes in the magnetic field due to bending of the finger, and because the device itself is not subject to physical stress, there is no deterioration due to repeated use of the device and durability. Does not decrease. Further, since the device is arranged so as to avoid the elastic part of the skin of the back of the joint, the joint motion can be detected without giving the subject a feeling of restraint.

[Brief description of drawings]

FIG. 1 is a side view (a) and a plan view (b) showing a mounted state of a first embodiment according to the present invention.

FIG. 2 is a view for explaining a magnetoelectric conversion element used in the same example.

FIG. 3 is a signal processing circuit diagram in the embodiment.

FIG. 4 is an output characteristic diagram of the same embodiment.

FIG. 5 is a side view (a) and a plan view (b) showing a mounted state of a second embodiment according to the present invention.

FIG. 6 is a side view (a) and a plan view (b) showing a mounted state of a third embodiment according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnet, 2 ... Magnetoelectric conversion element, 10 ... Signal processing circuit, 11 ... Base material, 12 ... Joint hole, 13
... Connecting part, 14 ... Beam

Claims (1)

[Claims] 1. A sensor for detecting a motion angle of a joint, comprising:
A magnet that forms a magnetic field in the vicinity of the joint, and a detection unit that detects the magnetic field. The magnet and the detection unit include:
A joint angle sensor, characterized in that a fixing portion is provided for mounting at an opposing position centered on an operating portion of the joint.