WO2002102290A1

WO2002102290A1 - Artificial muscle device and system using it

Info

Publication number: WO2002102290A1
Application number: PCT/KR2002/001128
Authority: WO
Inventors: Hoon-Bum Lee
Original assignee: Hb Medicals Corporation
Priority date: 2001-06-16
Filing date: 2002-06-15
Publication date: 2002-12-27
Also published as: KR20020095839A

Abstract

The present invention relates to an artificial muscle device and an artificial muscle system including it, more specifically, the muscle device capable of moving a muscle of which the regeneration became impossible due to paralysis of a motor nerve for a long time, or which needs continuous stimulation for recovery, and the artificial muscle system including it.

Description

ARTIFICIAL MUSCLE DEVICE AND SYSTEM USING IT

TECHNICAL FIELD

BACKGROUND ART

A muscle is a collection of muscular fibers, and a motor nerve works as moving the muscular fibers by stimulating them. Nerves are generally classified into a sensory nerve sensing a change and then transmitting it to the cerebrum or spinal cord, and a motor nerve moving a muscle by a command transmitted from the cerebrum or spinal cord. General nerves include the sensory nerve and the motor nerve together. When a nerve gets hurt, a muscle cannot move by command of the cerebrum or spinal cord. In this case, the muscle is alive even though the nerve is dead. Fortunately, if the nerve regenerates, the muscle can again move like in the normal state; however, when a long time has lapsed, the muscle degenerates because the fibrosis of muscular fiber occurs. In order to prevent a muscle from degenerating during the regeneration process of nerve, a physical treatment of stimulating periodically a muscle with a needle or electricity is generally performed. However, when the period exceeds about 2 years, the degeneration process is completed, whereby the treatment becomes impossible. Various methods have been developed to substitute the action of a nerve where a muscle cannot move because of damage of the nerve. For example, some prior arts move the muscle by simulating electrically it with electrodes attached to the paralyzed muscle. Among them, U.S. Pat. No. 4,580,569 shows a system in which an operation signal is obtained by the previously fixed motion of shoulder, and the signal is transformed to an electrical stimulation, and the electrical stimulation causes a paralyzed hand or artificial hand to move in a regular pattern. However, this system can be used to only a muscle being in the active state to move the paralyzed or artificial hand, thus, cannot be used to a degenerative muscle. In addition, this system is very complicated.

SUMMARY OF INVENTION

The objects of the present invention are to solve the problems described above for once and all.

An object of the present invention is to provide an artificial muscle device useful for a muscle which cannot move only by an electrically stimulation because the degeneration process of muscle is under way or was completed.

Another object of the present invention is to provide an artificial muscle system which operates the artificial muscle device by a signal from a sensor attached to body organs (e.g., other muscles) associated with a paralyzed muscle.

In order to accomplish these objects, an artificial muscle device according to the present invention comprises, a housing member of a cylinder shape with an ellipse cross-section; an electromagnet member fixed in a distal portion of the housing member, the electromagnet member generating a magnetic field upon supply of a current; a magnetic body member positioned in a proximal portion of the housing member, the magnetic body member moving forward and backward by operation of the electromagnet member, in which an extension spring is installed front the proximal end of magnetic body member; an attaching member extending from the distal end of housing member, the attaching member being attached to the originis (or terminalis) of a muscle or other body tissue around the originis (or terminalis); and an attaching member extending from the proximal end of magnetic body member via the spring, the attaching member being attached to the terminalis (or originis) of the muscle or other body tissue around the terminalis (or originis), wherein the space between these two attaching members becomes narrower upon application of the current, and the space is recovered by the spring upon non- application of the current.

Generally, while a part of muscle which is attached to a bone is called as "orginis," a part of muscle which is attached to other tissues is called as "terminalis." That a muscle operates normally means that the contraction occurs from the terminalis toward the orginis.

In the present invention, utilized is the principle that when a current is applied to a coil rolled on a cylinder, the magnetic field is generated and thus a magnetic body is pulled toward the cylinder by the magnetic field, whereas when a current is not applied to the coil, the magnetic field disappears and thus the magnetic body is not pulled.

The electromagnet member is fixed in the distal portion of the cylindrical housing member so that it does not move; therefore, when the magnetic field is generated, the magnetic body member moves toward the electromagnet member. In another embodiment, an artificial muscle device is configured that a magnetic body member is fixed in a housing member, and an electromagnet member moves toward the magnetic body member. More specifically, while the magnetic body member is fixed in one end of the housing member, the electromagnet member moves forward and backward on the other end thereof, and a compressive spring is installed between the magnetic body member and the electromagnet member. Accordingly, when the magnetic field is generated by applying a current to the electromagnet member, the pulling force is created between the magnetic body member and electromagnet member, whereby the electromagnet member moves toward the magnetic body member, and the spring is compressed. To the contrary, when the application of current is interrupted, the magnetic field disappears, and the electromagnet member comes back by the recovering force of compressive spring.

The configuration of electromagnet member of the present invention is not particularly limited, if it provides a force of pulling the magnetic body member upon application of a current. Accordingly, the configuration of electromagnet member may be of a hollow cylinder of which the outer surface is rolled by a coil, or a hollow cylinder of which the outer surface is rolled by a coil and in which a soft iron is inserted.

The magnetic body member acts as being pulled by the magnetic field generated from the electromagnet member. In another embodiment, the magnetic body member is a permanent magnet. The pole of permanent magnet is positioned to the direction where the pulling force is created between the permanent magnet and the electromagnet member. As a material of the magnetic body member, ferrite-based metals are not desirable, because the residual magnetism is made by repetitive generation and disappearance of the magnetic field. Where the permanent magnet is used as a magnetic body member, a large pulling force is created, which can be used to contract a large muscle.

The extension spring serves as hanging the magnetic body member to the proximal end of housing member, and has a small elasticity capable of being easily extended by the magnetic field generated from the electromagnet member. The number of extension springs is not particularly limited; however, in order to keep the balance of alternating motion of the magnetic body member, two extension springs are preferably used in the right and left positions. Connection of the extension spring and the housing member and connection of the extension spring and the magnetic body member can be made in various configurations; for example, both ends of extension springs are of a hook-shape, and the hooks are hooked to the corresponding fixtures of the housing member and magnetic body member. The extension spring is preferrably a plastic spring in which the residual magnetism is not created by repetitive generation and disappearance of the magnetic field.

In another embodiment, a guiding road is formed to guide the forward- backward movement of magnetic body member between the electromagnet member and the magnetic body member. The guiding road can be made in various configurations; for example, a small guiding wall extends longitudinally along the inner, lower surface of cylindrical housing member, and the corresponding longitudinal groove is formed on the lower surface of magnetic body member, so that the magnetic body member can moves forward and backward along the guiding wall.

The attaching members are attached to the originis and terminalis of a muscle or other body tissues around them, respectively, where one attaching member extends from the magnetic body member, and the other attaching member extends from the housing member. Preferably, a plurality of holes are perforated on these attaching members, wherein the attaching members are sutured to the orginis and terminalis of muscle or other tissues around them through the holes with a suture (stitching fiber). The shape of cylindrical housing member is not particularly limited, however, in order for the housing member to be implanted in a human subject without any inconvenience, its cross-section is desirably an ellipse or a rectangle with each edge rounded. Both ends of cylindrical housing member are sealed except a passage through which the bar of the attaching member moves. Muscles can be classified into one of a slow contraction and relaxation and one of a rapid contraction and relaxation. Accordingly, it is required that the moving speed of magnetic body member varies with the kind of muscle to be substituted with an artificial muscle device. Such moving speed of the magnetic body member can be determined by the magnitude of magnetic field, the kind of magnetic body member, the elasticity of spring, the frictional force of magnetic body member, etc. Therefore, the moving speed can be controlled by varying the ampere of current in an artificial muscle device of a certain dimension. Since the device of the present invention is implanted in a human subject, at least the portion, which comes in contact with a tissue, should be made of a biocompatible material. The housing member is preferably made of a silicone which is an insulating and biocompatible material.

The present invention also provides an artificial muscle system comprises the above artificial muscle device, and a power-supply/control means which supplies a current to the artificial muscle device and controls the ampere of current.

The power-supply/control means comprises a power supply part of supplying a current, and a control part of determining the supply and interruption of current and controlling the ampere of current. In another embodiment, a switch of determining the operation and stop of power-supply/control means is further included, or a switch of determining only the supply and interruption of current is used instead of the control part. The control part is very useful for the case where a current needs to be supplied periodically to move a muscle, so that the degeneration process of muscle is prevented until a motor nerve regenerates. The switch is useful for the case where a human controls directly such operation of the device.

Where a muscle should moves continuously according to change of a specific site of human body, it is necessary to move a muscle under such condition even though the muscle was completely degenerated or not so. In this case, a sensor is further included to sense the change of the specific site and transmit it to the power- supply/control means. The specific site as the above means muscles or organs other than the muscle to which the device is attached. For example, in the case where one of right-left symmetrical muscles such as facial muscles is paralyzed, the artificial device is installed on the paralyzed muscle, and a sensor is installed on the other normal muscle to sense the change thereof, whereby the paralyzed muscle moves according to the change of the normal muscle with the aid of the muscle device.

The sensor acts as sensing the change of a certain site of human body, for example, a pressure, an extension, etc. A plurality of sensors associated with such function have been known, e.g., in the paper of Rosengren, et. al. ("A system for passive implantable pressure sensors", Sensors and Actuactors A, 43, 55-58 (1994). L.

Rosengren, P. Rangsten, Y. Backhand, B. Hok, B. Svedbergh, and G. Selen).

As shown below, the description refers to the drawing in order to describe the present invention more in detail, thereby, the scope of the invention is however not to be interpreted as a limitation of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a perspective view of an artificial muscle device according to an embodiment of the present invention. In the artificial muscle device 100, an electromagnet member 300 is fixed in the distal portion of a flat, cylindrical body member 200, and a magnetic body member 400 is positioned in the proximal portion thereof. The electromagnet member 300 comprises a hollow cylinder 310 and a coil 320 which rolls the hollow cylinder 310; in another embodiment, however, a soft iron (not shown) is inserted into the hollow portion of cylinder 310.

A magnetic body member 400 is made of the metal such as a soft iron or a permanent magnet, and is connected to the proximal end of housing member 200 by an extension spring 500. Accordingly, when a current is applied to the coil 320, the magnetic body member 400 is pulled toward the electromagnet member 300, and when the current is interrupted, the magnetic body member 400 comes back to the original position by the extension spring 500, because the magnetic field creating the pulling force disappeared. Attaching members 600 are attached to the originis and terminalis of a muscle or other tissues around them. In order to reinforce the attachment, a suture procedure is performed by suturing the attaching members 500 with the muscle through a plurality of holes 610. The housing member 200 is sealed except a passage 220 through which connecting bars 620 move connecting the magnetic body member 400 to the attaching member 600. Guiding walls 230, which are longitudinally formed on the inner, lower surface of housing member 200, guide the forward-backward movement of the magnetic body member 400.

FIG. 2 shows an artificial muscle device according to another embodiment of the present invention. The artificial muscle device 110 of FIG. 2, unlike the artificial muscle device 100 of FIG. 1, comprises a magnetic body member 450 being fixed and an electromagnet member 350 moving. In other words, the magnetic body member 450 is fixed on the proximal portion of a housing member 250, and a compressive spring 550 is positioned between the electromagnet member 350 and the magnetic body member 450. The compressive spring 550 is different from the extension spring 500 of FIG. 1. In the state that a current is not supplied to the electromagnet member 350, the electromagnet member 350 is placed at the distal portion of housing 350 by the force of compressive spring 550. When the current is supplied to generate the magnetic field, the electromagnet member 350 moves toward the magnetic body member 450. The other configurations are the same as those in FIG. 1.

FIG. 3 shows the configuration of an artificial muscle system employing the artificial muscle device 100 of FIG. 1. The artificial muscle system comprises the artificial muscle device 100, a sensor 700, and a power-supply/control means 800. An example of using this artificial muscle system on facial muscles is shown in FIGS. 5 A and 5B.

First, FIG. 4 shows a part of a patient's facial muscles in which a right facial muscle (A) is paralyzed. Generally, when a part of facial muscles is paralyzed, the paralyzed side of a face sags; for example, the right muscle (A) is paralyzed as in FIG. 4 so that the right side of face sags. Meanwhile, since the left muscle (B) is in the normal state, the overall shape of face sags in the right side. The facial muscles generally tend to move symmetrically, thus, if the paralyzed, right muscle (A) is moved corresponding to movement of the normal, left muscle (B), the overall shape of face appears to be in the normal state.

Accordingly, referring to FIG. 5A, a sensor 700 is attached to a left muscle (B) of the face, and an artificial muscle device 100 is attached to a right muscle (A) corresponding to the left muscle (B), and these 100, 700 are connected to a power- supply/control means 800, respectively. The artificial muscle device 100 needs to be attached to the right muscle (A) in the somewhat strained state, because the face is shown normally in this strained state. The power-supply/control means 800 may be installed inside the human body or may be installed outside the human body. In another embodiment, a control part (not shown) constituting the power-supply/control part 800 is installed inside the human body, and only a power supply (not shown) is installed outside the human body. The power supply may be a first or secondary battery. Referring to FIG. 5A, when there is not any change in a left muscle (B), an artificial muscle device 100 attached to a right muscle (A) is in the relaxed state. Referring to FIG. 5B, as the left muscle (B) moves, such change (movement) is sensed by a sensor 700 and then transmitted to a power-supply/control means 800, and a current is supplied to the artificial muscle device 100 by the power-supply/control means 800. At this time, the magnetic field is generated by an electromagnet member 300 to pull a magnetic body member 400, whereby the space between attaching members 600 is shortened. The change of space between the attaching members 600 is the same as the change of length of the left muscle (B), which is controlled by changing the ampere of current in the power-supply/control means 800. FIG. 6 shows a schematic block diagram of an artificial muscle system according to the present invention. A piezo sensor 700 is connected to a power- supply/control means 800, and the power-supply/control means 800 operates upon ON of a switch 900. The power-supply/control means 800 comprises an amplifier 810, a low-pass filter 820, an A/D converter 830, a microprocessor 840, a D/A converter 850, and a constant current control circuit 870. In another embodiment, the part of constitutional elements such as the amplifier 810, the low-pass filter 820 and the like is configured to be included in the sensor 700. A signal transmitted from the piezo sensor 700 is amplified in the amplifier 810, and a noise of the amplified signal is removed by the low-pass filter 820. The analog signal is converted to a digital signal by the A/D converter 830 and then transmitted to the microprocessor 840. The microprocessor 840 calculates the extent of change in a muscle and then transmits an operating signal corresponding to the calculated value to the D/A converter 860. The D/A converter 860 converts this digital signal to an analog signal to transmit it to the constant current control circuit 860. Then, a current from a high voltage generation circuit 870 is supplied to an artificial muscle device 100 through the constant current control circuit 860, whereby the artificial muscle device 100 operates. FIG. 6B shows a schematic diagram of a circuit based upon the block diagram of

FIG. 6A. Referring to FIG. 6B, the A/D converter 830 and the D/A converter 850 are configured to be incorporated in the microprocessor 840. The detailed description on the diagram is omitted in the present specification for simplicity, because it can be easily understood by one skilled in the art. The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications would be obvious to one skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an artificial muscle device according to an embodiment of the present invention, in which a part of the device is expressed in a view of a cross-section.

FIG. 2 is a cross-sectional view of an artificial muscle device according to another embodiment of the present invention.

FIG. 3 is schematic view of an artificial muscle system employing the artificial muscle device of FIG. 1.

FIG. 4 is a front view of a face in which the right side is paralyzed.

FIGS. 5 A and 5B are procedure views of moving a facial muscle by using the artificial muscle system of FIG. 3.

FIG. 6A is a schematic block diagram of the artificial muscle system of FIG. 3. FIG. 6B is a schematic diagram of a circuit corresponding to the block diagram of FIG. 6A.

Designation of the reference numbers

100: artificial muscle device 200: housing member

300: electromagnet member

400: magnetic body member

500: extension spring

600: attaching member 700: sensor

800: power-supply/control means

INDUSTRIAL APPLICABILITY

By using an artificial muscle device of the present invention, it is possible to move a muscle being in the degeneration process or being entirely degenerated. Furthermore, by using an artificial muscle system including the artificial muscle device, it is possible to move a muscle according to the movement of a specific site in a human body by sensing such movement.

Claims

WHAT IS CLAIMED IS:

1. An artificial muscle device comprising a housing member of a cylinder shape with an ellipse cross-section; an electromagnet member fixed in a distal portion of the housing member, the electromagnet member generating a magnetic field upon supply of a current; a magnetic body member positioned in a proximal portion of the housing member, the magnetic body member moving forward and backward by operation of the electromagnet member, in which an extension spring is installed front the proximal end of magnetic body member; an attaching member extending from the distal end of housing member, the attaching member being attached to the originis (or terminalis) of a muscle or other body tissue around the originis (or terminalis); and an attaching member extending from the proximal end of magnetic body member via the spring, the attaching member being attached to the terminalis (or originis) of the muscle or other body tissue around the terminalis (or originis), wherein the space between these two attaching members becomes narrower upon application of the current, and the space is recovered by the spring upon non- application of the current.

2. The artificial muscle device according to claim 1, in which the configuration of electromagnet member is of a hollow cylinder of which the outer surface is rolled by a coil, or a hollow cylinder of which the outer surface is rolled by a coil and in which a soft iron is inserted.

3. The artificial muscle device according to claim 1, in which the magnetic body member is a permanent magnet wherein the pole of permanent magnet is positioned to the direction where the pulling force is created between the permanent magnet and the electromagnet member.

4. An artificial muscle device comprising a housing member of a cylinder shape with an ellipse cross-section; an electromagnet member positioned in a proximal portion of the housing member, the electromagnet member moving forward and backward by a magnetic field generated upon supply of a current; a magnetic body member fixed in a distal portion of the housing member, the magnetic body member pulling the electromagnet member upon supply of a current, in which a compressive spring is installed between the magnetic body member and the electromagnet member. an attaching member extending from the distal end of housing member, the attaching member being attached to the originis (or terminalis) of a muscle; and an attaching member extending from the proximal end of electromagnet member via the spring, the attaching member being attached to the terminalis (or originis) of the muscle, wherein the space between these two attaching members becomes narrower upon application of the current, and the space is recovered by the spring upon non- application of the current.

5. An artificial muscle system comprising the artificial muscle device according to one claims 1 to 4, and a power-supply/control means which supplies a current to the artificial muscle device and controls the ampere of current.

6. The artificial muscle system according to claim 5, in which a switch of determining the operation and stop of power-supply/control means is further included, or a switch of determining only the supply and interruption of current is further included.

7. The artificial muscle system according to claim 5, in which a sensor is further included to sense the change of a specific site of a human body and transmit it to the power-supply/control means.