Integrated system for driving and location recognition of mobile magnetic substances
The present disclosure relates to an integrated system for driving a magnetic body and recognizing the position thereof. The system includes a magnetic field generating unit having four electromagnetic coils radially spaced apart from each other by the same distance and a coil frame to which the electromagnetic coils are connected, an RF coil unit disposed in a through-hole included in the center of the coil frame, a driving unit orthogonal to the coil frame and connected to allow the coil frame to slide in one axial direction, and a processing unit configured to generate movement path information of the coil frame and desired current information of each of the electromagnetic coils.
1 . An integrated system for driving a magnetic body and recognizing a position thereof, the system comprising:
a magnetic field generating unit comprising four electromagnetic coils radially spaced apart from each other by an identical distance, and a coil frame to which the electromagnetic coils are connected;
an RF coil unit disposed in a through-hole included in a central portion of the coil frame;
a driving unit orthogonal to the coil frame and connected to allow the coil frame to slide in one axial direction; and
a processing unit configured to generate movement path information of the coil frame and desired current information of each of the four electromagnetic coils;
wherein a central axis of each of the four electromagnetic coils is directed toward the center of the coil frame,
wherein the driving unit moves the coil frame according to the movement path information, and
wherein the processing unit is configured to generate a field free point (FFP) or a field free line (FFL) through the magnetic field generating unit, set a first scan path that is a movement path of the field free point or the field free line, scan the magnetic body along the first scan path, receive a first reflection signal reflected from the magnetic body, and identify a first position of the magnetic body, which is a position on the Z-axis perpendicular to the magnetic field generating unit, by using the first reflection signal.
2 . The system of claim 1 , wherein each of the four electromagnetic coils comprises at least one selected from the group consisting of a solenoid coil, a circular coil, a square coil, and a saddle coil.
3 . The system of claim 1 , wherein the RF coil unit comprises an Rx coil and a Tx coil.
4 . The system of claim 1 , wherein the four electromagnetic coils form an angle of 45 degrees with respect to an axis perpendicular to the longitudinal axis of the driving unit.
5 . A method of recognizing a position of a magnetic body, the method comprising:
a path-setting operation of generating a field free point (FFP) or a field free line (FFL) through a magnetic field generating unit and setting a first scan path that is a movement path of the field free point or the field free line;
a first scan operation of scanning the magnetic body along the first scan path and receiving a first reflection signal reflected from the magnetic body;
a first position recognition operation of identifying a first position of the magnetic body, which is a position on the Z-axis perpendicular to the magnetic field generating unit, by using the first reflection signal;
a second scan operation of scanning the magnetic body along a second scan path on the XY plane perpendicular to the Z-axis, at the first position of the magnetic body and receiving a second reflection signal reflected from the magnetic body; and
a second position recognition operation of identifying a second position of the magnetic body on the XY plane by using the second reflection signal.
6 . The method of claim 5 , wherein the first scan path is calculated from movement path information of a coil frame and desired current information of an electromagnetic coil.
7 . The method of claim 6 , wherein the desired current information of the electromagnetic coil is calculated by Equation 13 below,
I=Q 0 −1 M u + D=[i 1 i 2 i 3 i 4 ] T [Equation 13]
wherein I, M u , D, and Q 0 satisfy I∈R n , M u ∈R m×n , D∈R m , and Q 0 ∈R m×m , respectively, M u is the square root of Q used for weighted-norm, and [i 1 i 2 i 3 i 4 ] T indicates current to be applied to four electromagnetic coils.
8 . The method of claim 5 , wherein the first scan operation further comprises a first filtering operation of filtering the first reflection signal.
9 . The method of claim 5 , wherein the magnetic field generating unit comprises four electromagnetic coils radially spaced apart from each other by an identical distance, and a coil frame to which the electromagnetic coils are connected.
10 . The method of claim 5 , wherein the first position recognition operation further comprises a calculation operation of calculating a second scan path.
11 . The method of claim 5 , wherein the second scan operation further comprises a second filtering operation of filtering the second reflection signal.
12 . The method of claim 5 , wherein the second position recognition operation further comprises a current position recognition operation of identifying current position of a magnetic body by using the first position and the second position.