JP4547536B2 - Electromagnetic angle measuring joint angle meter - Google Patents

Description

  The present invention relates to an electromagnetic wave measurement type joint angle meter used for equipment control devices related to rehabilitation engineering, virtual reality, or man-machine interface.

  For example, in rehabilitation, it is necessary to always check the state of training when training various joints such as the functions of various joints for walking and the joints of arms, wrists, and fingers for manual work. It is necessary to measure the angle of movement. Various measuring instruments are used to measure the angle of movement of such a joint. As the simplest one, a rotating side member is rotatably fixed to one end of a plastic fixed side member. A joint angle meter (goniometer) in which a protractor is fixed to the rotation base is widely used because of its low cost. In this joint angle meter, the fixed-side member part is fixed to the human body part of one of the two bones that are flexibly connected by the joint, and the rotating-side member is supported by the human part of the other bone side. Then, the rotation angle of the bone at the joint is statically measured with a protractor.

  The joint angle meter as described above is simply a combination of two plastic members and a protractor. Although it is inexpensive, the angle is measured visually so that it is easy to cause reading errors and is accurate. Requires skill. Moreover, it is cumbersome to always observe the joint movement during normal training work, especially when the trainee tries to move the joint appropriately for the changing target value. It is difficult to observe sequentially.

  As a countermeasure, an angle pulse generator for generating a pulse corresponding to the rotation angle of the rotation side member with respect to the fixed side member is provided in the mechanism as described above, and the rotation angle is digitally displayed by counting the pulses. Are also used. With such a device, it is possible to perform operations such as feeding back digital data to a separate training device and changing the target value.

In addition to the static function measurement as described above, it is necessary to measure a dynamic function such as a force on the joint periphery. A device combining a strain gauge and an electronic measuring device is used for such dynamic measurement. Such an apparatus is used in a rehabilitation device described in, for example, Japanese Patent Application Laid-Open No. 2003-175085 and the like in order to compare a joint motion targeted by a user with an actual motion.
JP 2003-175085 A

  In the joint angle meter used for measuring the target motion of the joint and the actual motion result in the rehabilitation as described above, the angle of the fixed side member and the rotation side member is pulse counted. The fixed side member is fixed, the rotating side member is fixed to the lower leg, and the rotation angle as the bending angle around the knee joint is measured, and it is necessary to fix these ruler parts to the human body. . For this reason, rehabilitation people attach foreign bodies to their bodies, and they feel uncomfortable with their movements, and the movements are limited to movements in the plane, hindering movements such as bending while twisting at the joints. As a result, a problem arises in that a load is applied to the angle measurement unit.

  In addition to the rehabilitation as described above, for example, when operating various devices, such a joint angle measuring means is a man scene interface for moving according to the movement of a human arm or hand, for example, the wrist of the operator. When operating the device by detecting the movement of the wrist, even when trying to use it to measure the rotation angle of the wrist joint, the foreign body must be fixed to the body as described above, and the movement is restricted. And you will feel uncomfortable. This is the same when, for example, joint angle measurement is performed in order to detect human movement in virtual reality or various games.

  Therefore, according to the present invention, in joint angle measurement for detecting movement at the joint portion, the foreign body is not fixed to the movement portion of the user, the joint angle is set without giving the user a sense of incongruity and without inhibiting the movement. The main object is to provide an electromagnetic wave measuring joint angle meter capable of measuring.

In order to solve the above problems, an electromagnetic wave measuring joint angle meter according to the present invention holds a transmitting antenna that transmits an electromagnetic wave from an AC signal generator and a receiving antenna that receives an electromagnetic wave from the transmitting antenna at a predetermined interval. An antenna unit, a reception signal strength detection unit that detects the strength of the reception signal received by the reception antenna, detection data of the reception signal strength detection unit, and joint angle data corresponding to the reception signal strength recorded in advance And a joint angle calculation unit for calculating the rotation angle of the joint accompanying the movement of the human body portion around the joint in the object detection range around the receiving antenna held by the antenna unit . It is characterized by that.

  Another electromagnetic wave measurement type joint angle meter according to the present invention is characterized in that in the electromagnetic wave measurement type joint angle meter, a single frequency electromagnetic wave having a frequency of 3 to 100 MHz is transmitted from the transmitting antenna.

  Another electromagnetic wave measuring joint angle meter according to the present invention is the electromagnetic wave measuring joint angle meter, wherein the electromagnetic wave measuring joint angle meter is used for any one of rehabilitation, virtual reality, and man-machine interface. .

  According to the present invention, since it is not necessary to fix any foreign matter to the movement part of the body, the movement of the joint part is not restricted, the user's movement is inhibited without giving a sense of incongruity to the user. Without this, it is possible to perform dynamic measurement of joint angles and static measurement. In addition, the joint angle measuring device according to the present invention is a wide range of fields as a measuring device in the field of rehabilitation engineering as a new basic principle of dynamic measurement of joint angles, and a measurement technique of human body movement in the virtual reality and man-machine interface fields. In addition, the present invention can be applied in place of other conventionally used means.

The electromagnetic wave measurement type joint angle meter according to the present invention is an electromagnetic wave that can measure the joint angle in a non-invasive manner without fixing a foreign object to the movement part of the user in the joint angle measurement for detecting the movement in the joint part. The problem of obtaining a measurement-type joint angle meter is that an antenna unit that holds an electromagnetic wave from an AC signal generation unit and a reception antenna that receives an electromagnetic wave from the transmission antenna at a predetermined interval, and the reception a received signal strength detector for detecting the intensity of the reception signal received by the antenna, and detecting data of the received signal strength detecting unit, based on the joint angle data corresponding to the received signal strength which is previously recorded, said antenna due to movement of the body portions around the joints in the object detection range around the receiving antenna which is held in part, joint angle for calculating the rotation angle of the joint It was achieved by Ru and a calculation unit.

    First, FIG. 3 showing the measurement principle of the present invention will be described. As shown in FIG. 3A, a transmission antenna in which an electromagnetic wave having a frequency of 3 to 100 MHz, which is a short wave band (HF) to a very short wave band (VHF), generated by an AC signal generation unit 31 is formed in a loop shape. A power of 100 mW or less of a single frequency is applied from 32 and a CW wave is transmitted. The electromagnetic wave transmitted from the transmission antenna 32 is received by the reception antenna 33 formed in the same manner, and the reception intensity is detected by the detection unit 34. Note that various antenna shapes such as a rectangular shape can be used at this time, and various antennas such as a circular or rectangular solenoid type antenna can be used in addition to a loop-shaped antenna.

  Between the transmitting antenna 32 and the receiving antenna 33, a water tank 35 filled with water in a resin container that is easy to obtain data accurately instead of a human body is traversed as shown in FIG. As a result of detecting the reception electric field intensity received by the reception antenna 33 at that time, that is, the reception signal intensity, by the detection unit 34, a result as shown in FIG. 3C was obtained. That is, according to the data of FIG. 3C, the dielectric constant changes around the center line 36 connecting the antennas, electromagnetic wave absorption and electromagnetic wave shielding due to eddy current loss, etc. occur, and the received signal strength is greatly reduced. all right. It can be seen that the relative dielectric constant of water at this frequency is about 70, which greatly changes the electric field. As a result, it is known that muscles, internal organs, and the like having a high water content in living tissues have a large dielectric constant like water, and these can be detected in the same manner.

  As the transmitting and receiving antennas used at this time, various conventional short wave and ultra high frequency band antennas can be used. For example, a loop antenna made of copper wire as shown in FIG. 4 is used. You can also. In this example, the antenna 41 uses a wire 42 having a diameter of about 1 mm wound in a ring shape having a diameter of about 40 mm, and a toroidal core 44 is used between the lead wire and the coaxial cable 43. It is connected via a transformer.

  Based on the above principle, the present invention can detect the movement of a part of a human body that moves at a joint as shown in FIG. That is, as shown in FIG. 3A, similarly to FIG. 3, the electromagnetic wave of the short wave band to the ultra high wave band generated by the AC signal generating unit 21 is transmitted from the transmitting antenna 22 and is opposed to this at an interval of, for example, 30 cm. The received signal is received by the received reception antenna 23 and the electric field strength at that time is detected by the detection unit 24.

  In such a state, as shown as an object detection range 25 in the figure, an object detection range 25 based on the principle shown in FIG. Magnetic field lines exist so as to surround the. When a part of the human body as an object including moisture exists in the object detection range 25 and moves, the detection unit 24 has the same characteristics as in FIG. 3C due to the change in dielectric constant and eddy current loss due to the movement. A change occurs in the strength of the received signal. As a result, the amount of movement of the object can be detected.

  The electromagnetic wave measuring joint angle meter having the above principle can be used as an apparatus as shown in FIG. That is, an antenna unit 27 that holds the transmitting antenna 22 and the receiving antenna 23 at a predetermined interval, and a main body unit that houses and arranges the AC signal generating unit 21, the received signal strength detecting unit 8, the control device 25, the operation unit, the display unit, and the like. The electromagnetic wave measurement type joint angle meter 26 can be configured by the coaxial cables 29 and 30 connecting between them and 28. However, the antenna portion 27 and the main body portion 28 may be integrated, and a gap is formed between the transmitting antenna 22 and the receiving antenna 23 to detect a part of the human body existing in this portion. Further, without providing such a gap, for example, all may be stored in a rectangular resin case.

  Based on the above principle, for example, the present invention can be configured as shown in FIG. 1 to measure the rotation angle θ at which the lower leg 4 is bent with respect to the upper leg 3 in the knee joint 2 of the foot 1. Also in this embodiment, a weak electromagnetic wave having a frequency of 3 to 100 MHz from the short wave band (HF) to the very high wave band (VHF) generated by the AC signal generation unit 5 as in the examples shown in FIGS. As shown in FIG. 4, a receiving antenna 7 is formed by transmitting electromagnetic waves transmitted from a small transmitting antenna 6 having a size of several centimeters formed by winding a plurality of copper wires in a loop shape. Then, the detection unit 8 detects the received signal strength.

  In such an arrangement state of the transmitting antenna 6 and the receiving antenna 7, the set of these antennas is set so that the axis of the upper leg 3 of the foot 1 is substantially in the same direction as the central axis 9 of the receiving antenna 6 and the transmitting antenna 7. By fixing the knee joint 2 to a side such as a chair in the state of being close to the upper leg 3, the knee joint 2 is positioned in the object detection range 10 on the opposite side of the receiving antenna 7 from the transmitting antenna 6 in the illustrated example. Deploy.

  Accordingly, the lower leg 7 is rotated around the knee joint 2 in the direction from the solid line position to the two-dot chain line position in FIG. Due to the movement, the position of the lower leg 4 in the object detection range 10 changes, and a change in dielectric constant due to a change in moisture distribution or a change due to eddy current loss occurs. Can be detected. Based on the received signal strength and joint angle characteristic data acquired in advance for each individual in the joint angle calculation unit 11, for example, as shown in FIG. θ can be obtained.

  Since the data at this time is obtained at high speed together with the movement of the lower leg 4, the movement state of the lower leg including the movement speed can be easily detected. At that time, for example, even when the lower leg 4 is bent at a high speed and then returned to its original state immediately after the largest bend, the instantaneous maximum rotation angle can be easily measured. In addition, when the lower leg 4 is bent at a high speed and data of a large rotation angle is finally obtained, and when the data is bent at a low speed and the data of the same rotation angle is finally obtained, Various measurements that have been difficult with conventional knee joint rotation angle measurement can be easily performed, for example, evaluation of rotation angle data can be appropriately performed.

  Since the present invention as described above can detect the rotation angle of each part of the body around the joint, each part of the human body as a signal input unit in virtual reality, for example, in addition to the field of rehabilitation as described above It can be effectively used as a detector that detects the movement of the human body or as a detection unit that detects the movement of the human body in the man-machine interface.

It is a schematic diagram of the Example of this invention. It is a figure which shows the principle which detects an object in this invention. It is a figure which shows a detection signal strength when moving a water tank between a transmission antenna and a receiving antenna as a basic principle of this invention. It is a figure which shows the example of the antenna used by this invention.

Explanation of symbols

1 foot 2 knee joint 3 upper leg 4 lower leg 5 AC signal generating unit 6 transmitting antenna 7 receiving antenna 8 received signal intensity detecting unit 9 central axis 10 object detection range 11 joint angle calculating unit

Claims (3)

An antenna unit for transmitting an electromagnetic wave from the AC signal generation unit and an antenna unit for holding a reception antenna for receiving the electromagnetic wave from the transmission antenna at a predetermined interval;
A received signal strength detector for detecting the strength of the received signal received by the receiving antenna;
And detecting data of the received signal strength detecting unit, and the center based on the corresponding joint angle data on the received signal strength which is previously recorded, the joints in the object detection range around the receiving antenna which is held in the antenna portion An electromagnetic wave measurement type joint angle meter , comprising: a joint angle calculation unit that calculates a rotation angle of the joint accompanying the movement of the portion of the human body.   The electromagnetic wave measuring joint angle meter according to claim 1, wherein a single frequency electromagnetic wave having a frequency of 3 to 100 MHz is transmitted from the transmitting antenna.   The electromagnetic wave measuring joint angle meter according to claim 1, wherein the electromagnetic wave measuring joint angle meter is used for any one of rehabilitation, virtual reality, and man-machine interface.

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