WO2022092554A1

WO2022092554A1 - Multi-degree-of-freedom medical robot

Info

Publication number: WO2022092554A1
Application number: PCT/KR2021/012403
Authority: WO
Inventors: 이성온; 류우석; 신현수
Original assignee: 주식회사 피치랩
Priority date: 2020-10-26
Filing date: 2021-09-13
Publication date: 2022-05-05
Also published as: KR102495396B1; KR20220055305A

Abstract

A multi-degree-of-freedom medical robot according to one embodiment comprises: a first link arm having a first front end portion and a first rear end portion; a first actuator provided at the first front end portion to rotate the first front end portion around a first rotary shaft; a second link arm having a second front end portion and a second rear end portion; a second actuator provided at the first rear end portion so as to rotate the second front end portion around a second rotary shaft; and a stimulation unit connected to the second rear end portion, wherein the stimulation unit can comprise: a linearly moving device connected to the second rear end portion; a pose adjuster connected to the linearly moving device to provide at least two types of degrees of freedom; and a magnetic stimulator connected to the pose adjuster.

Description

Multi-DOF robot for medical use

The present invention relates to a medical multi-DOF robot capable of providing 6-DOF motion to a magnetic stimulator.

The brain is an organ located inside the head and is the highest central organ of the nervous system. The brain is divided into cerebrum, cerebellum, midbrain, mesencephalon, pons and medulla, and generates brainwaves. EEG, also called electroencephalography (EEG), refers to the flow of electricity generated when signals are transmitted between cranial nerves in the nervous system. EEG differs when the brain processes various information and is the most important indicator of brain activity.

Applying electrical stimulation to the brain can treat or alleviate neurological symptoms such as hand tremors. Methods for applying electrical stimulation to the brain include an invasive brain electrical stimulation method and a non-invasive brain electrical stimulation method. The invasive brain electrical stimulation method is a method of inserting an electrode into the brain through surgery and applying an electrical signal to the electrode. On the other hand, the non-invasive brain electrical stimulation method is a method of attaching an electrode to the scalp and then applying an electrical signal to the electrode. The non-invasive brain electrical stimulation method has the advantage of being less costly and less risky than the invasive brain electrical stimulation method. Accordingly, research and development of an electrical stimulation device capable of applying electrical stimulation to the brain in a non-invasive manner is being conducted.

Non-invasive brain stimulation has been in the spotlight for the treatment of various neurological/psychiatric disorders, and representative techniques include transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and transcranial ultrasound stimulation (TUS). there is. In fact, treatment cases such as dementia, epilepsy, and depression have been reported by stimulating specific areas of the patient's brain.

Most of the non-invasive stimulation brain stimulation methods use a method of controlling the position and angle of stimulation by human hands, and it is difficult to accurately apply stimulation to a desired location, which has a disadvantage in that the reproducibility of the stimulation effect is poor. Therefore, despite the high expected performance, it has not yet been widely used.

In order to overcome this problem, recent efforts have been made to increase the accuracy of brain stimulation using robots. For example, in studies using ① the existing 6-DOF serial-type robot arm, ② the serial-type spherical mechanism, and ③ the 6-DOF parallel-type mechanism, brain stimulation performance could be greatly improved through precise stimulation. However, the serial type robot has low safety and has a problem that a large shock can be applied to a person's head if the control fails. Although possible, there is a problem in that the size of the equipment increases and it requires an expensive production cost.

Therefore, it is required to develop a brain stimulation device that secures high safety and high accuracy (that is, can smoothly perform patient's motion compensation), and can provide accurate and repetitive stimulation with low-cost and simple installation and operation. It is necessary to develop a capable equipment.

A medical multi-degree-of-freedom robot according to an embodiment of the present invention includes a first link arm having a first front end and a first rear end; a first actuator installed on the first front end to rotate the first front end about the first rotation axis; a second link arm having a second front end and a second rear end; a second actuator installed at the first rear end to rotate the second front end about a second rotation axis; and a stimulation unit connected to the second rear end, the stimulation unit comprising: a linear moving device connected to the second rear end; a posture control device connected to the linear movement device to provide two or more degrees of freedom; and a magnetic stimulator connected to the posture control device.

According to an embodiment, the posture adjusting device includes: a third link arm installed in the linear movement device and having a third front end and a third rear end; a fourth link arm having a fourth front end and a fourth rear end; a third actuator installed at the third rear end to rotate the fourth front end about the third rotation axis; a fifth link arm having a fifth front end and a fifth rear end; a fourth actuator installed on the fourth rear end to rotate the fifth front end about a fourth axis of rotation perpendicular to the third axis of rotation; a sixth link arm having a sixth front end and a sixth rear end; and a fifth actuator installed at the fifth rear end to rotate the sixth front end to a fifth axis of rotation perpendicular to the third and fourth axis of rotation, and the magnetic stimulator may be connected to the sixth rear end.

According to an embodiment, a torsion spring may be installed between the first actuator and the first front end, and between the second actuator and the second front end, respectively.

According to one embodiment, a stand installed on the ground; and a height adjustment unit installed on the top of the stand and connected to the first actuator, wherein the height adjustment unit adjusts the height of the first actuator so that the intersection of the first and second rotational axes coincides with the center of the head of the subject. there is.

According to an embodiment, the stimulation unit may include: a torque sensor installed at a sixth rear end; And it may further include a moving platform connected to the torque sensor.

According to an embodiment, the first actuator may include a first motor and a first reducer, the second actuator may include a second motor and a second reducer, and the first and second reducers may each be configured as a harmonic drive. there is.

According to one embodiment, the first actuator may further include a first brake for preventing free rotation of the first link arm, and the second actuator may further include a second brake for preventing free rotation of the second link arm. there is.

According to an embodiment, the distance between the first link arm and the center of the head of the stimulated person may be longer than the distance between the second link arm and the center of the head.

According to one embodiment, the extension lines of the third to fifth rotation shafts may be configured to intersect at one intersection point.

According to an embodiment, the intersection point may be configured to move along a linear axis of the linear movement device upon movement of the third link arm.

According to an embodiment, the first and second link arms are each configured in a spherical frame to surround the head of the subject, and the magnetic stimulator may be a non-invasive brain stimulator.

According to an embodiment, the posture adjusting device may be configured to control the posture of the magnetic stimulator by adjusting a roll, a pitch, and a yaw angle of the magnetic stimulator.

In a control method for a medical multi-DOF robot according to an embodiment of the present invention, the method comprising: setting a position and a direction of a stimulus focus with respect to a subject; calculating input values of the first to fifth actuators and the linear movement device by performing inverse kinematic analysis; moving the first and second link arms according to the input value; fixing the posture of the magnetic stimulator by moving the fourth to sixth link arms according to the input value; and moving the third link member according to the input value to fix the magnetic pole focus.

According to an embodiment, the method may further include the step of moving the third link member to adjust the magnetic pole focus and the contact force (calibration).

According to an embodiment, the method further includes changing the stimulus focus, wherein the changing of the stimulus focus includes: resetting the position and direction of another stimulus focus; calculating secondary input values of the first to fifth actuators and the linear movement device by performing inverse kinematic analysis according to the reset stimulus focus; moving the first to sixth link arms to initial positions; moving the first and second link arms according to the secondary input value; fixing the posture of the magnetic stimulator by moving the fourth to sixth link arms according to the secondary input value; and moving the third link member according to the secondary input value to fix the magnetic pole focus.

Since the medical multi-degree-of-freedom robot according to an embodiment of the present invention has two spherical arms, it is possible to secure a wider working area than the existing device based on a specific effective work area corresponding to the periphery of the human head, The possible collision between the human head and the robot is minimized, maximizing the safety of the victim.

In addition, the medical multi-degree-of-freedom robot can stimulate the brain at a desired position and angle, thereby enabling safe and precise brain stimulation. In addition, since the equipment can be manufactured at low cost, the penetration rate of equipment can be increased, the effect of brain stimulation treatment can be maximized by designing the device to enable self-treatment, and the reliability of related research can be greatly improved.

1 is a perspective view illustrating a medical multi-DOF robot according to an embodiment of the present invention.

2 is a perspective view illustrating a driving part of a medical multi-DOF robot according to an embodiment of the present invention.

3A is a perspective view illustrating the stimulation unit in FIG. 2 ;

FIG. 3B is a perspective view illustrating the stimulation unit shown in FIG. 2 as viewed from a different direction from that of FIG. 2 .

4 is a view showing a rotational movable range of the first rotary joint shown in FIG. 2 .

5 is a view showing a rotational movable range of the second rotary joint shown in FIG.

6 is a view showing the linear movable range of the linear joint shown in FIG.

FIG. 7 is a view for explaining an embodiment in which a torque sensor is installed in the stimulation unit shown in FIG. 2 .

8 is a view showing an operation state of the linear moving device shown in FIG.

9 is a view showing an operation state of the posture control device shown in FIG.

10 is a view showing a state in which a 'T' shape is applied to the link arm shown in FIG. 2 .

11 is a view for explaining the operation of the first rotary joint shown in FIG.

12 is a view for explaining the operation of the second rotary joint shown in FIG.

13 is a view for explaining the operation of the stimulation unit shown in FIG.

14 is a view for explaining a movable range of a medical multi-DOF robot.

15 is a flowchart illustrating a method for controlling a medical multi-DOF robot according to an embodiment of the present invention.

16 is a flowchart illustrating a step of changing a stimulus focus shown in FIG. 15 .

17 is a diagram for explaining inverse kinematic analysis.

18 is a block diagram for explaining a control and compensation process of a medical multi-DOF robot.

Embodiments of the present invention are presented by way of example to explain the technical spirit of the present invention. The scope of the rights according to the present invention is not limited to the following embodiments or specific descriptions of these embodiments.

1 is a perspective view showing a medical multi-DOF robot 1 according to an embodiment of the present invention.

The medical multi-DOF robot 1 has a serial-type mechanism structure in which a linear joint and a rotary joint of two or more degrees of freedom are additionally attached to a main link part having a spherical frame, and the overall size can be minimized.

The medical multi-DOF robot 1 is driven with a total of six degrees of freedom, and may be composed of a single two-DOF spherical frame, a linear actuator connected thereto, and an orientation mechanism module with two or more degrees of freedom. The direction conversion modules with more than two degrees of freedom are connected at right angles to each other and can be connected to the moving platform while inducing only the direction change of the end. A stimulator for brain stimulation may be attached to the moving platform.

The medical multi-DOF robot 1 may include a stand 10 , a first rotation joint 100 , a second rotation joint 200 , and a stimulation unit 300 . The first rotation joint 100 may include a first actuator 130 that rotates the first link arm 120 about the first link arm 120 and the first rotation shaft 110 . The second rotation joint 200 may include a second actuator 230 for rotating the second link arm 220 about the first link arm 220 and the second rotation shaft 210 . The stimulation unit 300 may include a linear joint having a linear movement axis 315 and third to fifth rotational joints, which will be described later in detail.

An angle between the extension line of the first rotation shaft 110 and the extension line of the second rotation shaft 120 may be approximately 50°. Also, an angle between the extension line of the second rotation shaft 120 and the extension line of the linear movement shaft 315 may be approximately 65°.

The stand 10 may be installed on the ground, and may be composed of a lower portion 11 and an upper portion 12 . A height adjustment unit 13 may be installed in the upper part 12 . A rail 14 may be formed on the upper portion 12 , and an actuator 15 may be installed on the upper portion of the rail 14 . The frame 16 is installed on the rail 14 and can be moved up and down along the rail 14 by an actuator 15 . The first actuator 130 may be installed in the frame 16 .

The height adjustment unit 13 moves the first actuator 130 so that the intersection point P ₁ of the first and

second rotation shafts

110 and 210 is the center of the head of the person stimulated by the stimulation unit 300 . It is possible to adjust the height of the first rotation joint 100 to match.

In this way, the height adjustment unit 13 provides one degree of freedom between the ground and the device, so that it is possible to position the rotation center of the positioning device at the center of the head of the subject.

2 is a perspective view showing a driving part of the medical multi-DOF robot 1 according to an embodiment of the present invention.

In the first rotation joint 100 , the first link arm 120 may have a first front end 121 and a first rear end 122 . The first actuator 130 may be installed on the first front end 121 to rotate the first front end 121 about the first rotational shaft 110 .

In the second rotation joint 200 , the second link arm 220 may have a second front end 221 and a second rear end 222 . The second actuator 230 may be installed on the first rear end 122 to rotate the second front end 221 about the second rotation shaft 210 . The stimulation unit 300 may be connected to the second rear end 222 .

The stimulation unit 300 includes a linear movement device 310 connected to the second rear end 222 , a posture adjustment apparatus 400 connected to the linear movement apparatus 310 to provide two or more degrees of freedom, and a posture adjustment apparatus It may include a magnetic stimulator 500 connected to the 400 .

The linear movement device 310 is connected to a ball screw to control the depth of the focus of the stimulator and is driven, and may include a rotation conversion module actuator with two or more degrees of freedom, a speed reducer, and a sensor for feedback of the position of the driving module.

The linear movement device 310 may include a linear frame 311 , an actuator 312 , and a third link arm 313 . The third link arm 313 is installed on the linear frame 311 and may be moved along the longitudinal direction of the linear frame 311 by the actuator 312 .

The linear joint 301 may include a linear movement device 310 and a third link arm 313 . The third rotation joint 401 may include a third actuator 420 and a fourth link arm 410 . The fourth rotation joint 402 may include a fourth actuator 440 and a fifth link arm 430 . The fifth rotation joint 403 may include a fifth actuator 460 and a sixth link arm 450 .

The linear movement device 310 may include a rail 311 , an actuator 312 , and a third link arm 313 . The third link arm 313 may be linearly moved along the rail 311 by the actuator 312 .

A first torsion spring 140 is installed between the first actuator 130 and the first front end portion 121 of the first link arm 120 , and the second actuator 230 and the second link arm 220 . A second torsion spring 240 may be installed between the second front end portions 211 . Since the first and second torsion springs 140 and 240 are provided as described above, even if the magnetic stimulator 500 collides with the subject, the torsion spring is able to absorb these shocks and the shock applied to the subject. can be minimized.

In this way, by attaching a torsion spring having high rigidity between each driving joint and the frame, physical damage applied to the subject when the subject's head and the robot arm collide can be minimized.

The first actuator 130 may include a first motor 131 and a first reducer 133 , and the second actuator 230 may include a second motor 231 and a second reducer 233 . Also, each of the first and second reduction gears 133 and 233 may be configured as a harmonic drive. The reduction ratio of the harmonic drive is about 100:1, so that the high torque can be finally transmitted to the link arm.

The first actuator 130 is disposed on the first motor 131 and the first reducer 133 and further includes a first brake 132 for preventing free rotation of the first link arm 120 , the second actuator Reference numeral 230 may further include a second brake 232 disposed between the second motor 231 and the second reduction gear 233 to prevent free rotation of the second link arm 220 . Accordingly, even when the power is turned off, the posture of the robot can be maintained without change.

The first and

second link arms

120 and 220 are each configured in a spherical frame so as to surround the head of the subject, and the magnetic stimulator 500 may be a non-invasive brain stimulator. As described above, when the stimulator moves around the subject's head using the spherical frame, since the subject's head is excluded from the effective operating range, it has high safety and can have a wide effective operating range.

The distance between the first link arm 120 and the center of the head of the subject may be longer than the distance between the second link arm 220 and the center of the head. Since the stimulation unit 300 is installed in the second link arm 220 and more detailed manipulation is possible in the stimulation unit 300 itself, the movement of the first link arm 120 is larger than that of the second link arm 220 . can provide

The posture adjusting device 400 may be configured to control the posture of the magnetic stimulator 500 by adjusting roll, pitch, and yaw angles of the magnetic stimulator 500 .

In the medical multi-DOF robot 1, a linear joint and a direction change joint of two or more degrees of freedom are added between the stimulator and the spherical frame, so that the depth and direction of the focus of the stimulator can be controlled in detail, and thus high accuracy can be achieved.

3A is a perspective view illustrating the stimulation unit 300 in FIG. 2 . FIG. 3B is a perspective view illustrating the stimulation unit 300 shown in FIG. 2 as viewed from a different direction from that of FIG. 2 .

The third link arm 313 may have a third front end 314 installed on the rail 311 and a third rear end 315 on which the third actuator 420 is installed. The fourth link arm 410 may have a fourth front end 411 and a fourth rear end 412 , and the third actuator 420 is installed at the third rear end 315 and the fourth front end ( 411 may be rotated about the third rotation shaft 425 .

The fifth link arm 430 may have a fifth front end 431 and a fifth rear end 432 , and the fourth actuator 440 is installed at the fourth rear end 412 and the fifth front end ( 431 may be rotated about a fourth rotational shaft 445 perpendicular to the third rotational shaft 425 . The sixth link arm 450 may have a sixth front end 451 and a sixth rear end 452 , and the fifth actuator 460 is installed at the fifth rear end 432 and installed at the sixth front end ( 451 may be rotated by a fifth rotation shaft 465 perpendicular to the third and fourth rotation shafts 425 and 445 . The magnetic stimulator 500 may be connected to the sixth rear end portion 452 .

Extension lines of the third to

fifth rotation shafts

425 , 445 , and 465 may be configured to intersect at one intersection point P ₂ . This intersection P ₂ may be configured to move along the linear axis 315 of the linear movement device 310 when the third link arm 313 moves.

The combination of the first and second

rotary joints

100 and 200 and the linear joint 310 can efficiently move the spherical surface around the subject's head by using a spherical link member, thereby securing high accuracy and driving speed. there is. In addition, it is possible to work on the entire area of the upper hemisphere of the subject's head. On the other hand, compared to the serial type robot, even when the control fails, safety can be secured because there is no area passing through the head of the subject in the work area of the end-effector of the robot. On the other hand, the focus and contact force control of the stimulation apparatus may be facilitated by the operation of the one-degree-of-freedom linear unit.

With respect to the posture adjusting device 400 , it may be easy to control the focal depth and angle of the stimulation apparatus through the combined driving of the fourth to

sixth link arms

410 , 430 , and 450 .

4 is a view showing a rotational movable range of the first rotary joint 100 shown in FIG. 2 . 5 is a view showing a rotational movable range of the second rotary joint 200 shown in FIG. 2 . 6 is a view showing the linear movable range of the linear joint 300 shown in FIG.

The reference position of the medical multi-degree-of-freedom robot 1 is a state in which the first and

second link arms

120 and 220 are aligned so that the stimulation unit 300 is at the highest position from the ground as shown in FIG. 1 . it means.

The driving range of each joint of the medical multi-DOF robot 1 may be limited to move only the entire area of the upper hemisphere of the subject's head, which is a target workspace.

In one embodiment, as shown in FIG. 5 , in the first rotary joint 100 , the first actuator 130 rotates the first link arm 120 between +100° and -100° from the reference position. driven, in the second rotation joint 200 , the second actuator 230 may be driven to rotate the second link arm 220 between +100° and -100° from the reference position.

In another embodiment, the first rotational joint may be rotated between +180° and -180°, and the driving of the second rotational joint may be limited to rotate in the range of 0° to 180°.

In the linear joint 301 , the actuator 312 may drive the third frame 313 to linearly move between 0 mm and 15 mm.

Meanwhile, in the third rotation joint 401 , the third actuator 420 may drive the fourth link arm 410 to rotate between +90° and -90° from the reference position. In the fourth rotation joint 402 , the fourth actuator 440 may drive the fifth link arm 430 to rotate between +90° and -90° from the reference position. In the fifth rotation joint 403 , the fifth actuator 460 may drive the sixth link arm 450 to rotate between +90° and -90° from the reference position.

FIG. 7 is a view for explaining an embodiment in which a torque sensor is installed in the stimulation unit 300 shown in FIG. 2 .

The stimulation unit 300 may include a torque sensor 530 installed on the sixth rear end 452 of the sixth link arm 450 . The magnetic stimulator 500 may be connected to the torque sensor 530 . The magnetic stimulator 500 may include a moving platform 510 directly connected to the torque sensor 530 and a magnetic field generator 520 . The moving platform 510 may have a shape surrounding the magnetic field generator 520 .

The torque sensor 530 may detect generation of 6-axis torque, and may sense a contact force when the magnetic stimulator 500 comes into contact with the head of the subject. In addition, when the torque sensor 530 detects a contact force greater than or equal to the reference force, the linear movement device 310 may be operated to move the magnetic stimulator 500 away from the head of the subject.

In this way, when the torque sensor 530 is used, the safety of the subject can be increased, and the touch force can be sensed, so that the stimulus can be performed with a force of an appropriate size when stimulating the object.

8 is a view showing an operation state of the linear moving device 310 shown in FIG. FIG. 9 is a view showing an operation state of the posture adjusting device 400 shown in FIG. 2 .

Fig. 8 (a) shows a state that the linear movement device 310 operates, and Figs. 8 (b) and 8 (c) show a state that the fifth rotary joint 403 operates. 9(a), (b), (c), and (d) illustrate a state in which the magnetic stimulator 500 moves while the third to fifth rotary joints 401 , 402 and 403 operate. In this way, by adjusting the posture of the magnetic stimulator 500, the depth and direction of the stimulation focus may be adjusted.

Since the first and

second link arms

120 and 220 have to withstand the high load of the stimulation unit 300, respectively, they may be configured as arms having a 'T'-shaped cross-section. When the arm has a 'T'-shaped cross-section, the moment of inertia increases compared to an arm having a general rectangular cross-section, thereby reducing the possibility of deformation due to a high load.

11 is a view for explaining the operation of the first rotary joint 100 shown in FIG. 12 is a view for explaining the operation of the second rotary joint 200 shown in FIG. 13 is a view for explaining the operation of the stimulation unit 300 shown in FIG. 14 is a view for explaining the movable range of the medical multi-degree-of-freedom robot 1 . For convenience of explanation, the drawings shown in FIGS. 1 to 3 are briefly expressed.

Referring to FIG. 11 , it can be confirmed to what extent the head of the subject can be covered by the operation of the first rotary joint 100 . Referring to FIG. 12 , it can be confirmed to what extent the head of the subject can be covered by the operation of the second rotary joint 200 beyond the movable range of the first rotary joint 100 . Referring to FIG. 13 , a process of adjusting the posture of the magnetic stimulator 500 through the operation of the linear joint 301 and the third to fifth rotational joints 401 , 402 , 403 can be confirmed.

As shown in FIG. 14 , the medical multi-DOF robot 1 can provide the magnetic stimulator 500 with motions of 5 to 6 degrees of freedom, and the upper hemisphere of the head of the target workspace, which is the target workspace. It can cover the entire area.

15 is a flowchart illustrating a control method (S1000) of the medical multi-DOF robot 1 according to an embodiment of the present invention.

The medical multi-DOF robot 1 may operate in the following order.

(1) Preparation stage

- Fixing the base for assembly and use of the device

- By using a linear actuator additionally attached to the base, the distance value between the center of the subject's head and the center of the sphere of the spherical frame is set to 0.

(2) Stimulation site input step

Information on the stimulation site of the stimulator prescribed by an expert is input into the device.

(3) Input steps such as stimulation time, stimulation intensity, etc.

Specify the desired stimulus intensity and time.

(4) stimulation phase

- Move the stimulator near the work area by driving the low-speed, high-output spherical frame responsible for large movements.

- Move the stimulator to the desired brain stimulation position and angle by simultaneously driving 5 or more actuators in the posture obtained through inverse kinematics analysis.

- The stimulator is activated and brain stimulation is performed as much as the specified amount of stimulation.

Next, with reference to FIG. 15, it demonstrates.

The control method (S1000) of the medical multi-DOF robot includes the steps of setting the position and direction of the stimulus focus with respect to the subject (S1100), and performing inverse kinematic analysis to obtain first to fifth actuators and a linear calculating an input value of the mobile device (S1200), moving the first and second link arms according to the input value (S1300); It may include the steps of fixing the posture of the magnetic stimulator by moving the fourth to sixth link arms according to the input value (S1400), and fixing the magnetic pole focus by moving the third link member according to the input value (S1500). can In addition, the control method (S1000) may further include a step (S1600) of adjusting the magnetic pole focus and the contact force by moving the third link member (S1600). Also, the control method ( S1000 ) may further include changing the stimulus focus ( S1700 ).

In step S1100, specifically, a total of six degrees of freedom of a position (x, y, z values) and a direction (Roll, Pitch, and Yaw values) may be set.

FIG. 16 is a flowchart illustrating a step S1700 of changing the stimulus focus shown in FIG. 15 .

The step of changing the stimulus focus (S1700) includes resetting the position and direction of another stimulus focus (S1710), performing inverse kinematic analysis according to the reset stimulus focus to obtain the first to fifth actuators and the linear Calculating a secondary input value of the moving device (S1720), moving the first to sixth link arms to an initial position (S1730), moving the first and second link arms according to the secondary input value (S1740), fixing the posture of the magnetic stimulator by moving the fourth to sixth link arms according to the secondary input value (S1750), and fixing the magnetic pole focus by moving the third link member according to the secondary input value It may include a step (S1760) of doing. On the other hand, the changing step (S1700) may further include the step (S1770) of adjusting the magnetic pole focus and the contact force by moving the third link member (S1770).

Thereafter, if the stimulus focus is to be further changed, the step of changing the stimulus focus based on the position and direction of another focus ( S1700 ) may be performed again.

17 is a diagram for explaining inverse kinematic analysis.

As shown in FIG. 17 , the basic coordinates and movement coordinates O (x, y, z) and P (u, v, w) are assigned to the ground and the magnetic stimulator 500 , respectively. For inverse kinematics analysis, two vector loops are used in kinematics. The first vector loop through points O, P, Q is a transformation (T ₁ ) containing information related to the desired posture. The second vector loop is the transformation (T ₂ ) from the origin (O) to the point Q via the actuator. Given the position vector of the stimulator (P=[P _x P _Y P _z ] ^T ) and the rotation matrix R _p , the transformation matrix T ₁ is obtained as

Formula (1):

where D _P is a transformation matrix from the origin to point P, and D(axis, value) is a transformation matrix that transforms along a specific axis. Then, the transformation matrix transformation (T ₂ ) composed of the input value (θ _i ) of the rotary joint and the input value (d) of the linear actuator can be expressed as follows.

Formula (2):

where R(axis, value) is a transformation matrix that rotates along a specific axis. In equations (1) and (2), r _d and r _s are the distances between point O and the initial position of the prismatic joint, and between point Q and the magnetic pole focus (P), respectively, and α and β are the spherical The design angle of the frame (ie, the first and second link arms). Since each component of T ₁ and T ₂ must be the same, the desired value (θ _i , d) of each joint is derived as follows.

Formula (3):

where c is cos and s is sin,

Using the derived input values, an end-effector (ie, magnetic stimulator 500 ) of the device can be positioned at a target location and orientation. At this time, the second revolute joint may be driven in the range of -100°<θ ₂ <100°, and the driving range of the first revolute joint is also set to -100°<θ ₁ <100°. can be

However, in order to prevent a singularity, the second revolute joint may be driven in the range of 0°<θ ₂ <180°, and the first revolute joint is also driven at -180° <θ ₁ <180°. A driving range can be set.

Hereinafter, the robot can be controlled using a position-based visual servoing (PBVS) method to compensate for unexpected human movements. Although the PBVS technique requires a 3D pose estimation process, the control method used in the existing Cartesian coordinate system can be used as it is.

Position and orientation errors used for feedback control can be defined as follows. In Euclidean geometry, the position error (e _p ) is defined using the difference between the desired position (p _d ) and the current working end position (p _e ).

Formula (4):

The rotation matrix R is a matrix that rotates the direction while maintaining the length of an arbitrary vector z as in Equation (5), and belongs to a special orthogonal group.

Formula (5):

Unlike the Euler angle, the rotation matrix has the advantage of not having a singularity, but it is difficult to adjust the gain. Below we use a rotation matrix that represents the orientation error of the controller.

We use the small angle approximation of the trigonometric function to define a new expression of orientation error (e ₀ ). If the input angle of the trigonometric function is very small, the sine function and the cosine function can be approximated and expressed as sinθ=θ and cosθ=1.

14 degrees and 8 degrees, respectively, and the error rate due to approximation is approximately 1%. Therefore, this approximation can be used because it is intended to compensate for slight movement of the subject. Given the desired orientation (R _d ), if the rotation of the working end (R _e ) is determined by the measuring system, the orientation error is

Formula (6):

A small angle approximation was applied to the rotation matrix using ZYX Euler angles in equation (6). Since small angles are assumed, we can assume that the second and third terms are also negligibly small.

Through this, the rotation error can be estimated by using the component values of the matrix as it is. After multiplying the estimated error by the gain, the final error (

) is found. Through this estimation, the advantage of the rotation matrix is that there is no singularity at any point, and the desired performance can be obtained by adjusting the gain for the direction error.

Formula (7):

The higher the speed compensated according to the gain value, the higher the risk of the experiment. Therefore, the gain can be set in consideration of the safety and performance of the experiment.

Although the technical spirit of the present invention has been described above, various substitutions, modifications and changes can be made without departing from the technical spirit and scope of the present invention that can be understood by those of ordinary skill in the art to which the present invention pertains. Also, such substitutions, modifications and variations are intended to be within the scope of the appended claims.

[Explanation of code]

1: Post support mechanism

10: stand

100, 200, 401, 402, 403: rotary joint

120, 220: link arm

300: stimulation unit

310: linear movement device

400: direction control device

500: magnetic stimulator

The present invention relates to a multi-degree-of-freedom robot for medical use. Since it is possible to stimulate the brain at a desired position and angle, safe and precise brain stimulation can be achieved, and equipment can be manufactured at low cost, thereby increasing the penetration rate of equipment. In addition, it is possible to maximize the effect of brain stimulation treatment by designing the device to allow self-treatment, so it has high industrial applicability.

Claims

a first link arm having a first front end and a first rear end;

a first actuator installed on the first front end to rotate the first front end about a first rotational axis;

a second link arm having a second front end and a second rear end;

a second actuator installed at the first rear end to rotate the second front end about a second rotation axis; and

and a stimulation unit connected to the second rear end,

The stimulation unit,

a linear moving device connected to the second rear end;

a posture control device connected to the linear movement device to provide two or more degrees of freedom; and

Comprising a magnetic stimulator connected to the posture control device,

A multi-degree-of-freedom robot for medical use.
According to claim 1,

The posture control device,

a third link arm installed on the linear moving device and having a third front end and a third rear end;

a fourth link arm having a fourth front end and a fourth rear end;

a third actuator installed at the third rear end to rotate the fourth front end about a third rotation axis;

a fifth link arm having a fifth front end and a fifth rear end;

a fourth actuator installed at the fourth rear end to rotate the fifth front end about a fourth axis of rotation perpendicular to the third axis of rotation;

a sixth link arm having a sixth front end and a sixth rear end; and

and a fifth actuator installed at the fifth rear end to rotate the sixth front end to a fifth rotational axis perpendicular to the third and fourth rotational axes,

The magnetic stimulator is connected to the sixth rear end,

A multi-degree-of-freedom robot for medical use.
The method of claim 1,

A torsion spring is installed between the first actuator and the first front end, and between the second actuator and the second front end, respectively,

pole support mechanism.
According to claim 1,

a stand installed on the ground; and

It is installed on the upper part of the stand and further comprises a height adjustment unit to which the first actuator is connected,

The height adjustment unit adjusts the height of the first actuator so that the intersection of the first and second rotation shafts coincides with the center of the head of the subject,

A multi-degree-of-freedom robot for medical use.
3. The method of claim 2,

The stimulation unit,

a torque sensor installed at the sixth rear end; and

Further comprising a moving platform connected to the torque sensor,

A multi-degree-of-freedom robot for medical use.
According to claim 1,

The first actuator includes a first motor and a first reducer,

The second actuator includes a second motor and a second reducer,

The first and second reducers are each composed of a harmonic drive,

A multi-degree-of-freedom robot for medical use.
7. The method of claim 6,

The first actuator further includes a first brake for preventing free rotation of the first link arm,

The second actuator further comprises a second brake for preventing the free rotation of the second link arm,

A multi-degree-of-freedom robot for medical use.
According to claim 1,

The distance between the first link arm and the center of the head of the stimulated person is longer than the distance between the second link arm and the center of the head,

A multi-degree-of-freedom robot for medical use.
3. The method of claim 2,

The extension lines of the third to fifth rotation axes are configured to intersect at one intersection point,

A multi-degree-of-freedom robot for medical use.
10. The method of claim 9,

the intersection is configured to move along a linear axis of the linear movement device upon movement of the third link arm;

A multi-degree-of-freedom robot for medical use.
According to claim 1,

The first and second link arms are each composed of a spherical frame to surround the head of the subject,

The magnetic stimulator is a non-invasive brain stimulator,

A multi-degree-of-freedom robot for medical use.
According to claim 1,

The posture adjusting device is configured to control the posture of the magnetic stimulator by adjusting a roll, pitch, and yaw angle of the magnetic stimulator.

A multi-degree-of-freedom robot for medical use.
In the control method of the medical multi-degree-of-freedom robot according to claim 1 to 12,

setting the position and direction of the stimulus focus with respect to the subject;

calculating input values of the first to fifth actuators and the linear movement device by performing inverse kinematic analysis;

moving the first and second link arms according to the input value;

fixing the posture of the magnetic stimulator by moving the fourth to sixth link arms according to the input value; and

Comprising the step of fixing the magnetic pole focus by moving the third link member according to the input value,

control method.
14. The method of claim 13,

Further comprising the step of moving the third link member to adjust the stimulus focus and the contact force (calibration),

control method.
14. The method of claim 13,

changing the stimulus focus;

Changing the stimulus focus comprises:

resetting the position and orientation of a different stimulus focus;

calculating secondary input values of the first to fifth actuators and the linear movement device by performing inverse kinematic analysis according to the reset stimulus focus;

moving the first to sixth link arms to an initial position;

moving the first and second link arms according to the secondary input value;

fixing the posture of the magnetic stimulator by moving the fourth to sixth link arms according to the secondary input value; and

Comprising the step of fixing the magnetic pole focus by moving the third link member according to the secondary input value,

control method.