Patent Description:
A conventional method of treating a vascular disease is performed by inserting a catheter through a femoral artery, dilating a blood vessel through a manual operation of a doctor, and installing an instrument that may maintain the dilated blood vessel, and such a method is referred to as coronary angioplasty. However, it is difficult to apply the catheter to complex blood vessels due to structural characteristics thereof, and the success of a procedure tends to be affected greatly by the skill of the doctor.

Recently, researches on a microrobot for a vascular treatment that may be wirelessly operated have been actively conducted by various advanced research institutes as a method to overcome such a disadvantage of the catheter. Although a structure in which a flexible leg is added to a microrobot has been developed to ensure stability and improve mobility when driven in a pulsating flow or performing drilling, the leg may cause damage to a blood vessel when rotating at a high speed.

For example, <CIT> describes a magnetic robot system comprising a catheter having a first magnet coupling part provided at the front end thereof; and a mobile robot having a second magnet coupling part provided at the rear end thereof, and having a driving magnet, wherein the mobile robot is coupled to the catheter by means of magnetic force between the first magnet coupling part and the second magnet coupling part, and the magnetic force coupling of the first magnet coupling part and the second magnet coupling part can be released by rotating magnetic torque generated by the driving magnet because of the application of external rotating magnetic force. <CIT> discloses micro-robot which is integratedly or detachably coupled to one end of a catheter or a guidewire for performing a medical operation using the catheter. <CIT> relates to a moving robot which has a first steering module and a movement module connected by a first connection unit. The movement module includes a movement magnet, which transmits a magnetic force to the first and second steering magnets and is capable of rotating while using a second direction perpendicular to the first direction as a rotary axis.

The present disclosure provides a microrobot capable of minimizing damage to an inner wall of a blood vessel.

In addition, the present disclosure provides a microrobot capable of improving accuracy of a treatment by stably performing a drilling process.

According to the present invention, a microrobot includes: a rotating shaft; a main magnet fixedly coupled to the rotating shaft; a first support body fitted around the rotating shaft, and rotatable about the rotating shaft; a first driving magnet fixedly coupled to the first support body, and having a magnetic moment having a magnitude that is smaller than a magnitude of a magnetic moment of the main magnet; and a plurality of first legs coupled to an outer circumferential surface of the first support body), when an external rotating magnetic field having a frequency that is smaller than the step-out frequency of the main magnet and larger than the step-out frequency of the first driving magnet is generated, the first driving magnet is not synchronized with the external rotating magnetic field and the main magnet is synchronized with the external rotating magnetic field, as claimed in independent claim <NUM>.

In addition, the microrobot may further include: a second support body fitted around the rotating shaft on an opposite side of the first support body with the main magnet interposed between the first support body and the second support body, and rotatable about the rotating shaft; a second driving magnet fixedly coupled to the second support body, and having a magnetic moment having a magnitude that is smaller than a magnitude of the magnetic moment of the main magnet; and a plurality of second legs coupled to an outer circumferential surface of the second support body.

In addition, the second driving magnet may have the magnetic moment having the magnitude that is equal to the magnitude of the magnetic moment of the first driving magnet.

In addition, the main magnet may include a cylindrical magnet, and may be configured such that an N-pole and an S-pole are arranged opposite to each other with the rotating shaft interposed therebetween.

In addition, the microrobot may further include a drill tip fixedly coupled to a front end of the rotating shaft, and configured to rotate integrally with the rotating shaft.

According to the present disclosure, a microrobot system includes: a microrobot according to the present invention; a magnetic field generation unit configured to generate the external rotating magnetic field on an outside of the microrobot.

In addition, the microrobot may include a second support body and a second driving magnet, which are fitted around the rotating shaft on an opposite side of the first support body with the main magnet interposed between the first support body and the second support body and the second driving magnet, and coupled integrally with each other so as to be rotatable about the rotating shaft, and the second driving magnet may have a magnetic moment having a magnitude that is smaller than the magnitude of the magnetic moment of the main magnet.

In addition, the magnetic field generation unit may include: a first mode for generating an external rotating magnetic field having a frequency that is smaller than a step-out frequency of each of the main magnet and the first driving magnet; and a second mode for generating an external rotating magnetic field having a frequency that is smaller than the step-out frequency of the main magnet and larger than the step-out frequency of the first driving magnet.

According to the present disclosure, in the first mode, the microrobot may move with a propulsion force generated from legs as a treatment unit and a driving unit rotate together with each other at a low speed, and in the second mode, the drilling process may be performed as the rotation of the driving unit is minimized and the treatment unit rotates at a high speed, so that the damage to the inner wall of the blood vessel can be minimized.

In addition, in the second mode, the drilling process may be performed while the leg of the driving unit is supported on the inner wall of the blood vessel so as to stably locate a rotating shaft of the treatment unit, so that the accuracy of the treatment can be increased.

According to the present disclosure, a microrobot includes: a rotating shaft; a main magnet fixedly coupled to the rotating shaft; a first support body fitted around the rotating shaft, and rotatable about the rotating shaft; a first driving magnet fixedly coupled to the first support body, and having a magnetic moment having a magnitude that is smaller than a magnitude of a magnetic moment of the main magnet; and a plurality of first legs coupled to an outer circumferential surface of the first support body.

However, the technical idea of the present invention is not limited to the embodiments described herein. The embodiments introduced herein are provided to sufficiently deliver the idea of the present invention to those skilled in the art so that the disclosed contents may become thorough and complete.

When it is mentioned in the present disclosure that one element is on another element, it means that one element may be directly formed on another element, or a third element may be interposed between one element and another element. Further, in the drawings, thicknesses of films and areas are exaggerated for efficient description of the technical contents.

In addition, in the various embodiments of the present disclosure, the terms such as first, second, and third are used to describe various elements, but the elements are not limited to the terms. The terms are used only to distinguish one element from another element. Therefore, an element mentioned as a first element in one embodiment may be mentioned as a second element in another embodiment. The embodiments described and illustrated herein include their complementary embodiments. Further, the term "and/or" used herein is used to include at least one of the elements enumerated before and after the term.

As used herein, the terms of a singular form may include plural forms unless the context clearly indicates otherwise. Further, the terms such as "including" and "having" are used to designate the presence of features, numbers, steps, elements, or combinations thereof described in the present disclosure, and shall not be construed to preclude any possibility of the presence or addition of one or more other features, numbers, steps, elements, or combinations thereof. In addition, the term "connection" used herein is used to include both indirectly and directly connecting a plurality of elements.

Further, in the following description of the present disclosure, detailed descriptions of known functions and configurations incorporated herein will be omitted when they may make the subject matter of the present invention unnecessarily unclear.

<FIG> is a view showing a microrobot system according to an embodiment of the present invention, and <FIG> is a sectional view showing a microrobot of <FIG>.

Referring to <FIG> and <FIG>, a microrobot system <NUM> may include a microrobot <NUM> and a magnetic field generation unit <NUM>.

The microrobot <NUM> may perform movement and drilling processes in various fluid environments such as tubular tissue in a human body and industrial piping. The microrobot <NUM> provided for a treatment of a blood vessel in a human body according to the present invention will be described for illustrative purposes.

The magnetic field generation unit <NUM> may generate an external rotating magnetic field from an outside of the microrobot <NUM>. The magnetic field generation unit <NUM> may generate the external rotating magnetic field from an outside of a patient into which the microrobot <NUM> is inserted. The magnetic field generation unit <NUM> may generate the external rotating magnetic field at frequencies having various magnitudes.

The microrobot <NUM> may include a treatment unit <NUM> and a driving unit <NUM>. The treatment unit <NUM> may performs a drilling process, and the driving unit <NUM> may generate a propulsion force that allows the microrobot <NUM> to move.

The treatment unit <NUM> may include a rotating shaft <NUM>, a main magnet <NUM>, and a drill tip <NUM>.

The rotating shaft <NUM> may have a rod shape having a predetermined length, and may be formed of a non-magnetic material. A latching sill <NUM> may be formed at a rear end of the rotating shaft <NUM>. The latching sill <NUM> may prevent the driving unit <NUM> from being separated.

The main magnet <NUM> may be a magnet having a cylindrical shape, and may have an inner space into which the rotating shaft <NUM> is inserted and fixed. The main magnet <NUM> may be configured such that an N-pole and an S-pole are arranged opposite to each other with the rotating shaft interposed therebetween.

The drill tip <NUM> may be fixedly coupled to a front end of the rotating shaft <NUM>. The drill tip <NUM> may be formed on an outer circumferential surface thereof with a spiral protrusion for the drilling process. The drill tip <NUM> may prevent the driving unit <NUM> from being separated.

The driving unit <NUM> may include a first support body <NUM>, a first driving magnet <NUM>, a first leg <NUM>, a second support body <NUM>, a second driving magnet <NUM>, and a second leg <NUM>.

The first support body <NUM> may have a cylindrical shape, and the rotating shaft <NUM> may be inserted into the first support body <NUM>. The first support body <NUM> may be located between the main magnet <NUM> and the drill tip <NUM>. The first support body <NUM> may be relatively rotatable about the rotating shaft <NUM>. The first support body <NUM> may be formed of a non-magnetic material.

The first driving magnet <NUM> may have a cylindrical shape having the same diameter as the first support body <NUM>, and may be coupled integrally with the first support body <NUM>. The first driving magnet <NUM> may be located between the first support body <NUM> and the drill tip <NUM>. The magnetic coupling of the first driving magnet <NUM> with the main magnet <NUM> may be blocked by the first support body <NUM>. The rotating shaft <NUM> may be inserted into the first driving magnet <NUM>. The first driving magnet <NUM> may be relatively rotatable about the rotating shaft <NUM>, integrally with the first support body <NUM>. The first driving magnet <NUM> has a magnetic moment having a magnitude that is smaller than a magnitude of a magnetic moment of the main magnet <NUM>.

A plurality of first legs <NUM> may be spaced apart from each other along a circumference of an outer circumferential surface of the first support body <NUM>, and one end of the first leg <NUM> may be coupled to the first support body <NUM>. The first leg <NUM> may have a rectangular plate shape having a thin thickness, and may be formed of a flexible material. According to the embodiment, three first legs <NUM> may be provided along a circumference of the first support body <NUM>.

The second support body <NUM> may have a cylindrical shape, and the rotating shaft <NUM> may be inserted into the second support body <NUM>. The second support body <NUM> may be located on an opposite side of the first support body <NUM> with respect to the main magnet <NUM>. The second support body <NUM> may be located between the main magnet <NUM> and the latching sill <NUM>. The second support body <NUM> may be formed in the same shape as the first support body <NUM>, and formed of the same material as the first support body <NUM>.

The second driving magnet <NUM> may have a cylindrical shape having the same diameter as the second support body <NUM>, and may be coupled integrally with the second support body <NUM>. The second driving magnet <NUM> may be located between the second support body <NUM> and the latching sill <NUM>. The magnetic coupling of the second driving magnet <NUM> with the main magnet <NUM> may be blocked by the second support body <NUM>. The rotating shaft <NUM> may be inserted into the second driving magnet <NUM>. The second driving magnet <NUM> may be relatively rotatable about the rotating shaft <NUM>, integrally with the second support body <NUM>. The second driving magnet <NUM> has a magnetic moment having a magnitude that is smaller than the magnitude of the magnetic moment of the main magnet <NUM>. The second driving magnet <NUM> may have a magnetic moment having a magnitude that is equal to the magnitude of the magnetic moment of the first driving magnet <NUM>.

A plurality of second legs <NUM> may be spaced apart from each other along a circumference of an outer circumferential surface of the second support body <NUM>, and one end of the second leg <NUM> may be coupled to the second support body <NUM>. The second leg <NUM> may have a rectangular plate shape having a thin thickness, and may be formed of a flexible material. According to the embodiment, three second legs <NUM> may be provided along a circumference of the second support body <NUM>.

Hereinafter, an operation process of the microrobot <NUM> through the magnetic field generation unit <NUM> will be described.

A magnetic torque applied to the magnets <NUM>, <NUM>, and <NUM> of the microrobot <NUM> within an external magnetic field may be expressed by the following formula.

In this case, T is a magnetic torque formed in a magnet by an external magnetic field, m is a magnetic moment of a magnet, and B is strength of an external magnetic field. From Formula (<NUM>), an external rotating magnetic field for generating a rotational motion of the microrobot <NUM> may be expressed by the following Formula (<NUM>).

In this case, B<NUM> is strength of an external rotating magnetic field, f is a frequency of an external rotating magnetic field, and t is a time.

According to Formula (<NUM>) described above, the rotational motion of the microrobot <NUM> may be generated by using the external rotating magnetic field.

Meanwhile, when a magnitude of a rotation frequency of the external magnetic field is increased, the step-out in which the rotational motion of the microrobot <NUM> is not synchronized with the external rotating magnetic field may occur. Since a frequency at which the step-out occurs is proportional to the magnetic moment of each of the magnets <NUM>, <NUM>, and <NUM>, the treatment unit <NUM> may have a large step-out frequency due to the main magnet <NUM> having a relatively large magnetic moment, and the driving unit <NUM> may have a small step-out frequency due to the driving magnets <NUM> and <NUM> having a relatively small magnetic moment. Therefore, a selective rotational motion of the driving unit <NUM> may be generated by adjusting the frequency of the external rotating magnetic field.

The step-out frequency may be expressed by the following Formula (<NUM>).

In this case, ω is a step-out frequency, and c is a drag coefficient, which varies according to surface friction, fluid viscosity, a robot shape, and the like.

The treatment unit <NUM> and the driving unit <NUM> may have step-out frequencies having mutually different magnitudes depending on a difference of the magnetic moments. Therefore, the magnetic field generation unit <NUM> may generate selective rotational motions of the treatment unit <NUM> and the driving unit <NUM> by adjusting the frequency of the external rotating magnetic field.

<FIG> and <FIG> are views showing rotational motions of a treatment unit and a driving unit according to a frequency of an external rotating magnetic field.

First, referring to <FIG>, the magnetic field generation unit <NUM> may include a first mode for generating an external rotating magnetic field <NUM> having a frequency that is smaller than a step-out frequency of each of the main magnet <NUM> and the first and second driving magnets <NUM> and <NUM>.

When the magnetic field generation unit <NUM> generates the external rotating magnetic field <NUM> having the frequency that is smaller than the step-out frequency of each of the main magnet <NUM> and the first and second driving magnets <NUM> and <NUM>, both the treatment unit <NUM> and the driving unit <NUM> may be aligned in a magnetic field direction to generate the rotational motions. Due to the rotational motion of the driving unit <NUM>, the flexible legs <NUM> and <NUM> may rotate to generate a propulsion force within a blood vessel <NUM>, so that the microrobot <NUM> may move.

Referring to <FIG>, the magnetic field generation unit <NUM> includes a second mode for generating an external rotating magnetic field <NUM> having a frequency that is smaller than the step-out frequency of the main magnet <NUM> and larger than the step-out frequency of each of the first and second drive magnets <NUM> and <NUM>.

According to the present invention, when the magnetic field generator <NUM> generates a frequency of the external rotating magnetic field <NUM> that is smaller than the step-out frequency of the main magnet <NUM> and greater than the step-out frequency of the first and second class magnets <NUM> and <NUM>, the driving unit <NUM> may not be synchronized with the external rotating magnetic field <NUM> so that the rotation of the driving unit <NUM> may be minimized, and only the treatment unit <NUM> may generate the rotational motion. Due to the rotational motion of the treatment unit <NUM>, the drill tip <NUM> may perform the drilling process on a lesion part <NUM>. In this case, since the legs <NUM> and <NUM> of the driving unit <NUM> are supported on an inner wall of the blood vessel <NUM>, a position of the drill tip <NUM> and the rotating shaft <NUM> may be fixed, so that accuracy of the treatment may be increased, and damage to the inner wall of the blood vessel <NUM> may be minimized.

Although the exemplary embodiments of the present invention have been described in detail, the scope of the present invention is not limited to a specific embodiment, and should be interpreted by the appended claims. In addition, it should be understood by those of ordinary skill in the art that various changes and modifications can be made without departing from the scope of the present invention.

Claim 1:
A microrobot (<NUM>) comprising:
a rotating shaft (<NUM>);
a main magnet (<NUM>) fixedly coupled to the rotating shaft (<NUM>);
a first support body (<NUM>) fitted around the rotating shaft (<NUM>), and rotatable about the rotating shaft (<NUM>);
a first driving magnet (<NUM>) fixedly coupled to the first support body (<NUM>), and having a magnetic moment having a magnitude that is smaller than a magnitude of a magnetic moment of the main magnet (<NUM>); and
a plurality of first legs (<NUM>) coupled to an outer circumferential surface of the first support body (<NUM>),
when an external rotating magnetic field (<NUM>) having a frequency that is smaller than the step-out frequency of the main magnet (<NUM>) and larger than the step-out frequency of the first driving magnet (<NUM>) is generated, the first driving magnet (<NUM>) is not synchronized with the external rotating magnetic field (<NUM>) and the main magnet (<NUM>) is synchronized with the external rotating magnetic field (<NUM>).