KR102221089B1 - Method and system for remotely controlling surgical slave arm - Google Patents

Abstract

A method of remotely controlling a surgical slave arm according to an embodiment includes receiving a command from an operator through a master arm, calculating target position data of the slave arm based on the received command, the calculation Calculating joint angles based on the determined target position data, modifying at least one of the calculated joint angles to be included within the motion range of the slave arm, the modified joint angles and the slave arm Determining next joint angles corresponding to the next position and posture of the slave arm based on current joint angles corresponding to the current position and posture, and controlling the slave arm to move according to the determined next joint angles. Includes.

Description

The method and system for remotely controlling surgical slave arm TECHNICAL FIELD

The present invention relates to a method and system for remotely controlling a surgical slave arm to move within a range of motion (運動範圍).

Medically, surgery refers to the treatment of diseases by cutting, cutting, or manipulating skin, mucous membranes, and other tissues using a medical machine. In particular, open surgery in which the skin of the surgical site is cut open and the internal organs, etc. are treated, formed or removed, due to problems such as bleeding, side effects, patient pain, and scars, in recent years, surgery using a robot It is in the spotlight as an alternative.

These surgical robots can be divided into a master arm that generates and transmits necessary signals by the manipulation of a doctor, and a slave arm that receives signals from the manipulation unit and directly applies necessary manipulations to the patient. , The master arm and the slave arm may be divided as each part of one surgical robot, or may be configured as separate devices and disposed in the operating room.

In the case of robotic surgery, the operator does not directly manipulate instruments required for surgery, but manipulates the master arm so that various instruments mounted on the slave arm perform operations necessary for surgery.

Inverse kinematics can be used in a process in which the operator manipulates the master arm and the movement of the slave arm is remotely controlled. Position data of a linear space may be converted into joint angles of a joint space by inverse kinematics. Here, the position data includes distances and rotation angles in the X-axis, Y-axis, and Z-axis directions with respect to the reference point.

When joint angles are calculated from position data using inverse kinematics, singularity may occur. When a singularity occurs, the slave arm can be controlled to move at an angle and angular velocity outside the range of motion in which it can physically move.

Accordingly, there is a need for a method of controlling a slave arm to move within a range of motion that can be physically movable.

Korean Patent Application Publication No. 10-2009-0127481

It is intended to provide a method and system for remotely controlling a surgical slave arm to move within a physically movable motion range.

The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

A method of remotely controlling a surgical slave arm according to an embodiment includes the steps of: receiving a command from an operator through a master arm; Calculating target position data of the slave arm based on the received command; Calculating joint angles based on the calculated target position data; Modifying at least one of the calculated joint angles to be included within the motion range of the slave arm; Determining next joint angles corresponding to the next position of the slave arm based on the modified joint angles and current joint angles corresponding to the current position of the slave arm; And controlling the slave arm to move according to the determined next joint angles.

In the above-described method, the step of modifying at least one of the calculated joint angles includes replacing a joint angle that is out of the motion range of the slave arm among the calculated joint angles with a value included in the motion range. It includes more.

In the above-described method, among the calculated joint angles, a joint angle out of the motion range of the slave arm is replaced by a boundary value of the motion range.

In the above-described method, the determining of the next joint angles of the slave arm further includes determining whether a difference between the position data calculated based on the modified joint angles and the target position data exceeds a first reference value. Include.

In the above-described method, determining the next joint angles of the slave arm further includes determining whether a difference between the modified joint angles and the current joint angles of the slave arm exceeds a second reference value.

In the above-described method, the determining of the next joint angles of the slave arm includes: when it is determined that the first reference value is exceeded or the second reference value is determined, the next joint angles of the slave arm are determined as the slave arm. Determining current joint angles of the arm; And otherwise, determining next joint angles of the slave arm as the modified joint angles.

The above-described method further includes providing an alarm to the operator when determining the next joint angles of the slave arm as the current joint angles of the slave arm.

In the above-described method, the alarm is displayed, output in the form of sound, or output in the form of vibration generated in the master arm or the slave arm and provided to the operator.

A surgical robot system according to another embodiment includes a master arm; Slave arm; And at least one processor for controlling the slave arm to move based on the operator manipulating the master arm, wherein the at least one processor obtains a command input from the operator through the master arm. ; Calculating target position data of the slave arm based on the acquired command; Calculating joint angles based on the calculated target position data; Modifying at least one of the calculated joint angles to be included within the motion range of the slave arm; Determining next joint angles corresponding to the next position of the slave arm based on the modified joint angles and current joint angles corresponding to the current position of the slave arm; And controlling the slave arm to move according to the determined next joint angles.

In the above-described surgical robot system, the at least one processor replaces a joint angle out of the motion range of the slave arm among the calculated joint angles with a value included in the motion range.

The slave arm may be controlled to move to a position and posture that can be physically moved, or the slave arm may be controlled to not move at an excessive angle and angular velocity. In addition, the slave arm can be controlled to move to the position and posture input by the operator command.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a plan view showing an embodiment of a surgical robot system.
2 is a flow chart showing an example of a method of remotely controlling a slave arm.
3 is a flow chart illustrating an example of a method of determining the following joint angles.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. It goes without saying that the following description is only for specifying the embodiments and does not limit or limit the scope of the invention. What can be easily inferred by experts in the art from the detailed description and examples is interpreted as belonging to the scope of the rights.

The terms “consisting of” or “including” used herein should not be construed as necessarily including all of the various elements or various steps described in the specification, and some of the elements or some steps It should be construed that they may not be included or may further include additional elements or steps.

Terms used in the present specification have selected general terms that are currently widely used as possible while considering functions in the present invention, but this may vary depending on the intention or precedent of a technician working in the field, the emergence of new technologies, and the like. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning of the terms will be described in detail in the description of the corresponding invention. Therefore, the terms used in the present invention should be defined based on the meaning of the term and the overall contents of the present invention, not a simple name of the term.

1 is a plan view showing an embodiment of a surgical robot system.

Referring to FIG. 1, a robotic system for surgery 1 according to an embodiment includes a slave robot 10 performing surgery on a patient P lying on an operating table 2, and a slave robot 10 with an operator (O ) Includes a master console 20 for remote control. In addition, the surgical robot system 1 may include a vision cart 30. Through the display unit 35 of the vision cart 30, the assistant A can check the progress of the operation.

The slave robot 10 may include one or more slave arms 11. In general, the robot arm refers to a device that has a function similar to that of a human arm and/or wrist and can attach a predetermined tool to the wrist. In the present specification, the slave arm 11 may be defined as a concept encompassing all components such as upper arm, lower arm, wrist, and elbow, and surgical instruments coupled to the wrist. As such, the slave arm 11 of the slave robot 10 may be implemented to be driven with multiple degrees of freedom. The slave arm 11 is, for example, a surgical instrument inserted into the surgical site of the patient P, a transfer driving unit that moves the surgical instrument in the longitudinal direction, a rotation driving unit that rotates the surgical instrument, and is installed at the end of the surgical instrument. It may be configured to include a surgical instrument driving unit for incising or cutting the lesion. However, the configuration of the slave arm 11 is not limited thereto, and it should be understood that this example does not limit the scope of the present invention.

One or more slave robots 10 may be used to operate the patient P, and the surgical tool 12 for displaying an image image through a display member (not shown) is an independent slave robot. It may be implemented as (10).

In addition, as described above, the embodiments of the present invention can be used universally in operations in which various surgical endoscopes (eg, thoracoscopic, arthroscopic, parenteral, etc.) are used other than laparoscopy.

The master console 20 and the slave robot 10 do not necessarily have to be separated into separate devices that are physically independent, and may be integrated into one and configured as an integral type.

The master console 20 includes a master arm (not shown) and a display member (not shown). In addition, the master console 20 may further include an external display device 25 capable of displaying the status of the operator O on the outside.

In detail, the master console 20 has a master arm so that the operator O can operate it. When the operator O manipulates the master arm, an operation signal is transmitted to the slave robot 10 through a wired or wireless communication network, and the slave arm 11 is controlled. That is, surgical operations such as position movement, rotation, and cutting of the slave arm 11 may be performed by manipulating the master arm of the operator O.

An image captured by the surgical tool 12 is displayed as an image on the display member of the master console 20. In addition, a predetermined virtual operation panel may be displayed on the display member together with an image photographed through the surgical tool 12 or may be displayed independently.

The display member may be provided in various forms through which the operator O can check an image. For example, a display device may be installed to correspond to both eyes of the operator O. As another example, it may be configured with one or more monitors, and information necessary for surgery may be individually displayed on each monitor. The number of display members may be variously determined according to the type or type of information required to be displayed.

The vision cart 30 is installed to be spaced apart from the slave robot 10 or the master console 20, and the progress of the surgery can be checked from the outside through the display unit 35.

The image displayed on the display unit 35 may be the same as the image displayed on the display member of the operator O. The assistant A may assist the operator O in the operation while checking the image of the display unit 35. For example, the assistant (A) may replace the surgical tool 12 in the instrument cart 3 according to the progress of the operation.

The central control unit 40 is connected to the slave robot 10, the master console 20, and the vision cart 30, and may transmit and receive respective signals.

The central control unit 40 includes at least one processor that controls the slave arm 11 to move based on the operator O manipulating the master arm. At least one processor may be implemented as an array of a plurality of logic gates, and may be implemented as a combination of a general-purpose microprocessor and a memory in which a program executable in the microprocessor is stored.

At least one processor may control the slave arm 11 to move within a physically movable motion range. Hereinafter, a method of remotely controlling the slave arm 11 to move within a physically movable motion range will be described with reference to FIGS. 2 and 3.

2 is a flow chart showing an example of a method of remotely controlling a slave arm.

In step S210, at least one processor may receive a command for controlling the slave arm from the operator through the master arm. The master arm may include an operation lever, and a command may be input through the operation lever.

The operation lever may have various mechanical configurations. For example, the operation lever may be in the form of a handle. The shape of the operation lever is not limited, and may be in various shapes such as a joystick, a keypad, a trackball, and a touch screen.

In step S220, at least one processor may calculate the target position data T_target of the slave arm based on the received command.

The position data is data representing a position (position and posture) of an object in a linear space, and may include distances and rotation angles in the X-axis, Y-axis, and Z-axis directions with respect to the reference point.

The at least one processor may calculate target position data T_target indicating the position of the target slave arm based on the received command.

For example, the target position data T_target may be expressed as Equation 1 below.

(Equation 1)

T_target = {X_target, Y_target, Z_target, RX_target, RY_target, RZ_target}

Here, X_target, Y_target, and Z_target represent target positions in the X-axis, Y-axis, and Z-axis directions of the slave arm with respect to the reference point, respectively, and RX_target, RY_target, and RZ_target are the X-axis and Y of the slave arm with respect to the reference point, respectively. Axis and the target rotation angle in the Z-axis direction. The target posture of the slave arm can be determined by RX_target, RY_target, and RZ_target.

That is, in step S220, at least one processor may calculate the target position and posture of the slave arm based on the operator manipulating the master arm.

In step S230, at least one processor may calculate the joint angles (q_calculated_1, q_calculated_2, ..., q_calculated_n) based on the calculated target position data T_target.

The slave arm contains links and joints. As the motor mounted on the joint rotates, the link rotates, and the position and posture of the slave arm may be changed. Accordingly, in order to control the position and posture of the slave arm to change according to the calculated target position data T_target, the joint angle at which the motor should rotate must be calculated.

The joint angles (q_calculated_1, q_calculated_2, ..., q_calculated_n) can be calculated by inverse kinematics converting from linear space to joint space. When the set of joint angles is referred to as Q_calculated and the derivative for mapping from the joint space to the linear space is referred to as J, the joint angles Q_calculated can be calculated by Equation 2 below.

(Equation 2)

Q_calculated = J ^-1 x T_target

That is, in step S230, at least one processor may convert the target position data T_target in the linear space into joint angles Q_calculated in the joint space.

In step S240, the at least one processor may modify at least one of the calculated joint angles Q_calculated to be included within the motion range of the slave arm.

When a singularity occurs in the process of calculating the joint angles Q_calculated by inverse kinematics, the calculated joint angles Q_calculated may have a value out of the motion range of the slave arm. Alternatively, when the target position data T_target is a position and posture out of the motion range of the slave arm, the calculated joint angles Q_calculated may have a value out of the motion range of the slave arm.

The motion range of the slave arm refers to the range of the rotation angle in which the joint (joint) of the slave arm can physically move. If the slave arm is controlled beyond its range of motion, it may break or fail.

The at least one processor determines whether the calculated joint angles Q_calculated out of the motion range of the slave arm, and corrects the joint angle out of the motion range to be included within the motion range.

At least one processor may substitute a value included in the motion range so that a joint angle outside the motion range is included within the motion range.

For example, when q_calculated_1 among the calculated joint angles is out of the motion range of the slave arm, q_calculated_1 may be substituted with a value included in the motion range. For another example, when q_calculated_2 and q_calculated_n among the calculated joint angles are out of the motion range of the slave arm, q_calculated_2 and q_calculated_n may be modified to values included in the motion range.

The at least one processor may replace the motion range boundary value so that the joint angle outside the motion range is included within the motion range.

For example, if q_calculated_1 of the calculated joint angles is out of the motion range of the slave arm and the boundary value of the motion range of the joint corresponding to q_calculated_1 is 1.5 rad, q_calculated_1 may be substituted with 1.5 rad.

As described above, among the calculated joint angles, the joint angle that is out of the motion range of the slave arm is modified to be included within the motion range, so that the slave arm can be prevented from being out of the motion range.

In addition, by directly replacing the joint angle without modifying the derivative J, it is possible to intuitively control the slave arm so that it does not deviate from the motion range. By using an intuitive control method, if a slave arm fails or malfunctions, control errors can be detected more quickly.

In step S250, the at least one processor may determine next joint angles Q_next of the slave arm based on the modified joint angles Q_modified and the current joint angles Q_current.

Here, the current joint angles Q_current mean joint angles corresponding to the current position (position and posture) of the slave arm. Next joint angles Q_next mean joint angles corresponding to the next position (position and posture) in which the slave arm should move.

In step S260, the at least one processor may control the slave arm to move according to the joint angles Q_next after being determined.

When the next joint angles Q_next are determined as the modified joint angles Q_modified, at least one processor may control the slave arm to move according to the modified joint angles Q_modified.

When the next joint angles Q_next are determined as the current joint angles Q_current, at least one processor may control the slave arm to maintain the current position and posture.

In order to describe step S250 in more detail, refer to FIG. 3.

3 is a flow chart illustrating an example of a method of determining the following joint angles.

In step S251, the at least one processor determines whether a difference between the position data T_calculated of the slave arm and target position data T_target of the slave arm, calculated based on the modified joint angles Q_modified, exceeds a first reference value.

The position data T_calculated of the slave arm may be calculated from the joint angles Q_modified modified using forward kinematics. For example, when J is a derivative mapping from a joint space to a linear space, the position data T_calculated of the slave arm may be calculated by Equation 3 below.

(Equation 3)

T_calculated = J x Q_modified

For example, target position data T_target of the slave arm may be expressed according to Equation 1, and the calculated position data T_calculated of the slave arm may be expressed according to Equation 4 below.

(Equation 4)

T_calculated = {X_calculated, Y_calculated, Z_calculated, RX_calculated, RY_calculated, RZ_calculated}

For example, the at least one processor may determine whether a norm of a difference between the target position data T_target and the calculated position data T_calculated exceeds the first reference value according to Equation 5 below. In this case, the first reference value may be a constant.

(Equation 5)

∥T_calculated-T_target∥

For another example, the at least one processor may determine whether a difference between elements of the target position data T_target and the calculated position data T_calculated exceeds the first reference value, according to Equation 6 below. In this case, the first reference value may be a vector having constants as elements. Since it is determined whether the difference between each element exceeds the first reference value, it is possible to precisely determine whether the slave arm can move to a target position and posture.

(Equation 6)

|X_calculated-X_target|

|Y_calculated-Y_target|

|Z_calculated-Z_target|

|RX_calculated-RX_target|

|RY_calculated-RY_target|

|RZ_calculated-RZ_target|

For another example, the at least one processor may compare a difference between a position and a posture between the target position data T_target and the calculated position data T_calculated with the first reference value, respectively.

The at least one processor may compare the target position data T_target and the calculated position data T_calculated in various other ways, and is not limited to the described embodiments.

The target position data T_target represents the position and posture input by the operator's command, and the calculated position data T_calculated represents the calculated position and posture so that the slave arm moves within the motion range. Therefore, by comparing the target position data T_target and the calculated position data T_calculated, it is determined whether the slave arm is controlled to move with the position and posture input by the operator command, and whether the slave arm is controlled to move at an excessive angle and angular velocity. I can judge.

In step S252, the at least one processor determines whether a difference between the modified joint angles Q_modified and the current joint angles Q_current exceeds a second reference value.

In the same manner as in step S251, the at least one processor may determine whether a norm of the difference between the modified joint angles Q_modified and the current joint angles Q_current exceeds the second reference value. Alternatively, the at least one processor may determine whether a difference between elements of the modified joint angles Q_modified and the current joint angles Q_current exceeds the second reference value, respectively.

The modified joint angles Q_modified represent joint angles calculated so that the slave arm moves within the range of motion, and the current joint angles Q_current represent joint angles with respect to the position and posture of the current slave arm. Accordingly, by comparing the modified joint angles Q_modified and the current joint angles Q_current, it is possible to determine whether the slave arm is controlled to move at an excessive angle and angular velocity.

In step S253, the at least one processor determines the next joint angles Q_next as current joint angles Q_current of the slave arm.

Step S253 is a step performed when any one of the condition of step S251 and the condition of step S252 is satisfied. That is, in step S253, the difference between the slave arm position data T_calculated and the slave arm target position data T_target calculated based on the corrected joint angles Q_modified exceeds the first reference value, or the modified joint angles Q_modified and the current joint angle This step is performed when the difference between the Q_currents exceeds the second reference value.

Satisfying either the condition of step S251 and the condition of step S252 means a case where the slave arm is controlled to move to a position and posture where it cannot be moved, or the slave arm is controlled to move at an excessive angle and angular velocity. In this case, the slave arm may be damaged or broken. Accordingly, in order to prevent this, at least one processor may lock the movement of the slave arm by determining the next joint angles Q_next as the current joint angles Q_current.

At least one processor may notify the operator that the movement of the slave arm is locked through an alarm. The alarm is displayed through the display member of the master console (20 in Fig. 1), an external display device (25 in Fig. 1), and the display unit of the vision cart (35 in Fig. 1), and transmitted to the operator, or to the operator in the form of sound. It may be transmitted or transmitted to the operator in the form of vibrations generated by the master arm or the slave arm.

In step S254, the at least one processor determines the next joint angles Q_next as modified joint angles Q_modified.

Step S254 is a step performed when both the condition of step S251 and the condition of step S252 are not satisfied. That is, in step S254, the difference between the slave arm position data T_calculated and the target position data T_target of the slave arm calculated based on the modified joint angles Q_modified does not exceed the first reference value, and the modified joint angles Q_modified and the current joint This step is performed when the difference between the angles Q_current does not exceed the second reference value.

Not satisfying both the condition of step S251 and the condition of step S252 means that the slave arm is controlled to move to a physically movable position and posture. Accordingly, at least one processor may control the slave arm to move according to the modified joint angles Q_modified by determining the next joint angles Q_next as the modified joint angles Q_modified.

Although the embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also the scope of the present invention. Belongs to.

1: surgical robot system 10: slave robot
11: slave arm 20: master console
30: vision cart 40: central control unit

Claims (10)

In a method for remotely controlling a surgical slave arm,
Receiving a command from an operator through a master arm;
Calculating target position data of the slave arm based on the received command;
Calculating joint angles based on the calculated target position data;
Modifying at least one of the calculated joint angles to be included within the motion range of the slave arm;
Determining next joint angles corresponding to the next position of the slave arm based on the modified joint angles and current joint angles corresponding to the current position of the slave arm; And
Controlling the slave arm to move according to the determined next joint angles,
The step of modifying at least one of the calculated joint angles,
And substituting a joint angle out of the motion range of the slave arm among the calculated joint angles with a value included in the motion range. delete The method of claim 1,
Among the calculated joint angles, a joint angle out of the motion range of the slave arm is replaced by a boundary value of the motion range. The method of claim 1,
The step of determining the next joint angles of the slave arm,
The method further comprising determining whether a difference between the position data calculated based on the modified joint angles and the target position data exceeds a first reference value. The method of claim 4,
The step of determining the next joint angles of the slave arm,
And determining whether a difference between the modified joint angles and the current joint angles of the slave arm exceeds a second reference value. The method of claim 5,
The step of determining the next joint angles of the slave arm,
Determining the next joint angles of the slave arm as current joint angles of the slave arm when it is determined that it exceeds the first reference value or exceeds the second reference value; And
Otherwise, the method further comprising determining next joint angles of the slave arm as the modified joint angles. The method of claim 6,
And providing an alarm to the operator when determining the next joint angles of the slave arm as current joint angles of the slave arm. The method of claim 7,
The alarm is displayed, output in the form of sound, or output in the form of vibration generated in the master arm or the slave arm and provided to the operator. Master arm;
Slave arm; And
At least one processor for controlling the slave arm to move based on an operator manipulating the master arm,
The at least one processor,
Acquiring a command input through the master arm from the operator;
Calculating target position data of the slave arm based on the acquired command;
Calculating joint angles based on the calculated target position data;
Modifying at least one of the calculated joint angles to be included within the motion range of the slave arm;
Determining next joint angles corresponding to the next position of the slave arm based on the modified joint angles and current joint angles corresponding to the current position of the slave arm; And
Performing the step of controlling the slave arm to move according to the determined next joint angles,
The at least one processor,
Among the calculated joint angles, a joint angle outside the motion range of the slave arm is substituted with a value included in the motion range. delete

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