Surgical robot system and control method thereof

Abstract

To avoid interference between a robot arm and an object around the robot arm, and ensure the continuity of surgery.SOLUTION: A system 10 includes: a robot arm 3 having a tip part 32 to which a surgical instrument 40 having a longitudinal axis C can be attached and a plurality of drive shafts, the number of the plurality of drive shafts being larger than a minimum degree of freedom required to control a position and a posture of the surgical instrument 40; an operation device 2 that receives an operation input of an operator for controlling the position and the posture of the surgical instrument 40; and a control device 28 that controls the robot arm 3 based on the operation input. The tip part 32 includes an instrument driving part 38 that rotates at least a part of the surgical instrument 40 around the longitudinal axis C. The control device 28 controls the instrument drive unit 38 to maintain the proximity distance between the robot arm 3 and the object present around the robot arm 3 to be equal to or greater than the allowable minimum distance.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] This disclosure relates to a surgical robot system and a control method thereof. [Background technology]

[0002] Conventionally, surgical robot systems have been disclosed that use robots to operate surgical instruments instead of surgeons directly handling and operating surgical instruments. Surgical robot systems are used, for example, in minimally invasive surgery, which can reduce the burden on patients undergoing surgery.

[0003] A surgical robot system typically includes a surgical robot located near the patient and an operating device that allows a surgeon to remotely operate the surgical robot. The operating device operated by the surgeon is located, for example, inside an operating room where a surgical bed on which the patient is placed is located. The surgical robot has a robotic arm, to which surgical instruments are detachably attached. The surgical instruments attached to the robotic arm are configured to be inserted, for example, into a port member provided in the patient. The port member is, for example, a trocar or cannula. Types of surgical instruments include forceps, electrocautery, staplers, endoscopes, etc., and are selected appropriately depending on the surgical procedure, etc. When a surgical robot has multiple robotic arms, different types of surgical instruments may be attached to each robotic arm, or the same type of surgical instrument may be attached to two or more robotic arms. For example, an endoscope may be attached to one robotic arm and forceps to two or more other robotic arms.

[0004] A surgeon (operator) can control the position and orientation of a surgical instrument attached to a robot arm by operating the operating device to operate the surgical robot. In cases where the surgical instrument itself has movable parts such as joints, such as forceps, the operating device can also be used to operate the movable parts of the surgical instrument. This allows the surgeon to control the position and orientation of the surgical instrument (and the movable parts, if any) using the operating device. For example, in cases where a surgical instrument has a pair of jaws attached to the tip of a shaft, the surgeon can control the position and orientation of the entire surgical instrument by operating the operating device, as well as the opening and closing of the pair of jaws or the rotation around the pitch axis and / or yaw axis. Furthermore, in cases where the shaft itself is rotatable around its longitudinal axis, the surgeon can rotate the shaft of the surgical instrument (around the roll axis) by operating the operating device.

[0005] In conventional surgical robot systems, the robot arm of a surgical robot generally has multiple drive axes (joints). The multiple drive axes (joints) of the robot arm of a surgical robot generally include rotary joints, and may also have prismatic joints. The number of drive axes (joints) provided in the robot arm, i.e., the degrees of freedom of the robot arm, must be at least the same as the degrees of freedom required to control the position and orientation of the surgical instrument.

[0006] Among conventional surgical robot systems, there are those equipped with a surgical robot having a robot arm with more degrees of freedom than are necessary to control the position and orientation of a surgical instrument (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2021 / 112193 Summary of the Invention [Problem to be solved by the invention]

[0008] Patent Document 1 describes a surgical system and a method for controlling a surgical manipulator arm, and describes an invention for solving the problem of interference with other devices in the surgical system, such as an adjacent manipulator arm, or with the surrounding environment, when operating the manipulator arm. However, the invention described in Patent Document 1 leaves room for further improvement.

[0009] This disclosure has been made to solve the above-mentioned problems, and one purpose of this disclosure is to provide a surgical robot system and a control method thereof that can avoid interference between the robot arm and objects around the robot arm and ensure the continuity of surgery. [Means for solving the problem]

[0010] (Aspect 1) Aspect 1 of this disclosure is a surgical robot system comprising: a robotic arm having a tip end to which a surgical instrument having a longitudinal axis can be attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than the minimum degrees of freedom required to control the position and attitude of the surgical instrument; an operation device that receives operation input from an operator to control the position and attitude of the surgical instrument; and a control device that controls the robotic arm based on the operation input, wherein the tip end has an instrument drive unit that rotates at least a portion of the surgical instrument around the longitudinal axis, and the control device controls the instrument drive unit to maintain a proximity distance between the robotic arm and an object present around the robotic arm that is equal to or greater than the minimum allowable distance.

[0011] (Aspect 2) Aspect 2 of this disclosure is a surgical robot system described in aspect 1, wherein the control device operates the instrument drive unit to rotate at least a portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold.

[0012] (Aspect 3) Aspect 3 of this disclosure is a surgical robot system described in aspect 1 or 2, wherein the proximity distance is the distance between a reference portion of the robot arm and the object, the robot arm has a translational movement mechanism that moves the surgical instrument along the longitudinal axis, and the reference portion includes at least a portion of the translational movement mechanism.

[0013] (Aspect 4) Aspect 4 of this disclosure is a surgical robot system described in any one of aspects 1 to 3, wherein at least a portion of the surgical instrument is configured to be inserted into a port member provided in a patient, and the number of the multiple drive axes of the robot arm is greater than the minimum degrees of freedom required to control the position and orientation of the surgical instrument with at least a portion of the surgical instrument inserted into the port member.

[0014] (Aspect 5) Aspect 5 of this disclosure is a surgical robot system described in any one of aspects 1 to 4, wherein the control device determines the proximity distance based on an arm model generated by modeling at least a portion of the robot arm.

[0015] (Aspect 6) Aspect 6 of this disclosure is a surgical robot system described in aspect 5, wherein the control device operates the robot arm on the arm model to determine one of two rotational directions about the longitudinal axis of at least a portion of the surgical instrument that increases the proximity distance.

[0016] (Aspect 7) Aspect 7 of this disclosure is a surgical robot system described in aspect 5 or 6, wherein the robotic arm has a translational movement mechanism that moves the surgical instrument along the longitudinal axis, and the at least part of the robotic arm is at least part of the translational movement mechanism.

[0017] (Aspect 8) Aspect 8 of this disclosure is a surgical robot system described in any one of aspects 1 to 7, wherein the object is another robotic arm to which another surgical instrument can be attached, the operating device accepts operation input from the operator to control the position and posture of the surgical instrument attached to the robotic arm and the position and posture of the other surgical instrument attached to the other robotic arm, and the control device controls the robotic arm and the other robotic arm based on the operation input.

[0018] (Aspect 9) Aspect 9 of this disclosure is a surgical robot system described in aspect 8, wherein the other robot arm has a tip end to which the other surgical instrument having a different longitudinal axis can be attached and multiple drive shafts, the number of the multiple drive shafts being greater than the minimum degrees of freedom required to control the position and posture of the other surgical instrument, the tip end of the other robot arm has a different instrument drive unit that rotates at least a portion of the other surgical instrument around the different longitudinal axis, and the control device adjusts the proximity distance by operating at least one of the instrument drive unit and the other instrument drive unit.

[0019] (Aspect 10) Aspect 10 of this disclosure is a surgical robot system according to aspect 9, wherein the control device selects, from among the robot arm and the other robot arm, a robot arm that is operating by operation of the operation input as the robot arm to be adjusted, and adjusts the proximity distance by operating the instrument driving unit of the robot arm to be adjusted.

[0020] (Aspect 11) An eleventh aspect of the present disclosure is a surgical robot system according to any one of aspects 1 to 10, further comprising the surgical instrument provided at the tip of the robot arm.

[0021] (Aspect 12) Aspect 12 of this disclosure is a surgical robot system according to any one of Aspects 1 to 11, wherein the robot arm has a base end, a torsion joint disposed at the base end, and a bending joint disposed between the tip end and the base end, and the control device controls the robot arm to intersect the rotation axis of the bending joint with a reference plane including the longitudinal axis and fix the orientation of the rotation axis of the bending joint relative to the reference plane, set a predetermined center point, set a reference point on a reference line that is an extension of the rotation axis of the torsion joint or a line offset in a direction perpendicular to the extension line, control the robot arm to position the longitudinal axis at the center point and position the reference plane at the reference point, and adjust the offset amount of the reference point in the direction perpendicular to the extension line to control the direction and amount of movement of the instrument driver, thereby maintaining the approach distance equal to or greater than the allowable minimum distance.

[0022] (Aspect 13) Aspect 13 of the present disclosure is a surgical robot system according to aspect 12, wherein the perpendicular direction of the extension line is horizontal.

[0023] (Aspect 14) Aspect 14 of this disclosure is a surgical robot system described in aspect 12 or 13, further comprising an arm base that holds the base end of the robot arm and the base end of another robot arm, the arm base having a longitudinal axis, and the perpendicular direction of the extension line being parallel to the longitudinal axis of the arm base.

[0024] (Aspect 15) Aspect 15 of this disclosure is a control method for a surgical robot system comprising: a robot arm having a tip end to which a surgical instrument having a longitudinal axis is attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than the minimum degrees of freedom required to control the position and attitude of the surgical instrument; an operation device that receives operation input from an operator to control the position and attitude of the surgical instrument; and a control device that controls the robot arm based on the operation input, wherein the method comprises: rotating at least a portion of the surgical instrument around the longitudinal axis using an instrument drive unit that constitutes at least a part of the tip end; and controlling the instrument drive unit to maintain a proximity distance between the robot arm and an object present around the robot arm that is greater than or equal to the minimum allowable distance.

[0025] (Aspect 16) Aspect 16 of this disclosure is a control method for a surgical robot system described in aspect 15, in which, when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold, the instrument driving unit is operated to rotate at least a portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance.

[0026] (Aspect 17) Aspect 17 of the disclosure is a computer-readable medium storing computer-readable instructions that, when executed by a processor of a surgical robot system, cause the processor to execute a control method for the surgical robot system, the surgical robot system comprising: a robotic arm having a tip end to which a surgical instrument having a longitudinal axis is attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than the minimum degrees of freedom required to control the position and orientation of the surgical instrument; an operation device that accepts operation input from an operator to control the position and orientation of the surgical instrument; and a control device that controls the robotic arm based on the operation input, the control method comprising: rotating at least a portion of the surgical instrument about the longitudinal axis using an instrument drive unit that constitutes at least a part of the tip end; and controlling the instrument drive unit to maintain a proximity distance between the robotic arm and an object present around the robotic arm that is greater than or equal to a minimum allowable distance.

[0027] (Aspect 18) Aspect 18 of this disclosure is a computer-readable medium described in aspect 17, wherein the control method operates the instrument driver to rotate at least a portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold.

[0028] (Aspect 19) Aspect 19 of this disclosure is a surgical robot system comprising: a robot arm having a tip end to which a surgical instrument can be attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than the minimum degrees of freedom required to control the position and posture of the surgical instrument; an operation device that accepts operation input from an operator to control the position and posture of the surgical instrument; and a control device that controls the robot arm based on the operation input, wherein the control device defines at least one of the plurality of drive shafts as a redundant drive shaft, controls the redundant drive shaft based on the operation input and constraint conditions, and adjusts the constraint conditions to maintain a proximity distance between the robot arm and an object present around the robot arm at or above the minimum allowable distance.

[0029] (Aspect 20) Aspect 20 of the present disclosure is a surgical robot system described in aspect 19, wherein the surgical instrument has a longitudinal axis and the redundant drive shaft rotates at least a portion of the surgical instrument about the longitudinal axis.

[0030] (Aspect 21) Aspect 21 of this disclosure is a surgical robot system described in aspect 20, wherein the control device rotates at least a portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold.

[0031] (Aspect 22) Aspect 22 of this disclosure is a control method for a surgical robot system comprising: a robot arm having a tip end with a surgical instrument attached and a plurality of drive shafts, the number of which is greater than the minimum degrees of freedom required to control the position and posture of the surgical instrument; an operation device that accepts operation input from an operator to control the position and posture of the surgical instrument; and a control device that controls the robot arm based on the operation input, wherein the control method defines at least one of the plurality of drive shafts as a redundant drive shaft, controls the redundant drive shaft based on the operation input and constraint conditions, and adjusts the constraint conditions to maintain a proximity distance between the robot arm and an object present around the robot arm at or above the minimum allowable distance.

[0032] (Aspect 23) Aspect 23 of this disclosure is a method of controlling a surgical robot system described in aspect 22, wherein the surgical instrument has a longitudinal axis and the redundant drive shaft rotates at least a portion of the surgical instrument around the longitudinal axis.

[0033] (Aspect 24) Aspect 24 of this disclosure is a control method for a surgical robot system described in aspect 23, in which, when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold, at least a portion of the surgical instrument is rotated around the longitudinal axis in a direction that increases the proximity distance.

[0034] (Aspect 25) Aspect 25 of this disclosure is a computer-readable medium storing computer-readable instructions that, when executed by a processor of a surgical robot system, cause the processor to execute a control method for the surgical robot system, the surgical robot system comprising: a robotic arm having a tip end with a surgical instrument attached and multiple drive shafts, the number of the multiple drive shafts being greater than the minimum degrees of freedom required to control the position and orientation of the surgical instrument; an operation device that accepts operation input from an operator to control the position and orientation of the surgical instrument; and a control device that controls the robotic arm based on the operation input, the control method defining at least one of the multiple drive shafts as a redundant drive shaft, controlling the redundant drive shaft based on the operation input and constraint conditions, and adjusting the constraint conditions to maintain a proximity distance between the robotic arm and an object present around the robotic arm at or above an allowable minimum distance.

[0035] (Aspect 26) Aspect 26 of this disclosure is a computer-readable medium described in aspect 25, wherein the surgical instrument has a longitudinal axis and the control method rotates at least a portion of the surgical instrument about the longitudinal axis by the redundant drive shaft.

[0036] (Aspect 27) Aspect 27 of this disclosure is a computer-readable medium described in aspect 26, wherein the control method rotates at least a portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold. [Effects of the Invention]

[0037] According to the surgical robot system and the control method thereof disclosed herein, it is possible to avoid interference between the robot arm and objects around the robot arm, thereby ensuring the continuity of surgery. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of a surgical robot system according to one embodiment. [Figure 2] FIG. 1 is a plan view showing a schematic configuration of a surgical robot system according to one embodiment. [Figure 3] FIG. 1 is a side view showing a schematic configuration of a surgical robot system according to one embodiment. [Figure 4] FIG. 2 is another side view showing the schematic configuration of the surgical robot system according to the embodiment. [Figure 5] FIG. 1 is a perspective view showing a schematic configuration of a surgical instrument attached to a robot arm of a surgical robot system according to one embodiment. [Figure 6] FIG. 10 is a perspective view showing a schematic configuration of another surgical instrument attached to the robot arm of the surgical robot system according to one embodiment. [Figure 7] FIG. 2 is a block diagram illustrating a system configuration of an arm control unit of a surgical robot system according to one embodiment. [Figure 8] FIG. 1 is a perspective view showing a schematic configuration of a robot arm and a surgical instrument of a surgical robot system according to one embodiment. [Figure 9] FIG. 1 is a perspective view showing a schematic configuration of a distal end of a robot arm of a surgical robot system according to one embodiment and a surgical instrument attached to the distal end. [Figure 10] FIG. 1 is a perspective view showing a schematic configuration of a distal end portion of a robot arm of a surgical robot system according to one embodiment. [Figure 11] FIG. 1 is a diagram showing a schematic configuration of an arm base and a robot arm attached to the arm base of a surgical robot system according to one embodiment. [Figure 12] FIG. 1 is a block diagram illustrating a schematic configuration of a drive control system of a surgical robot system according to one embodiment. [Figure 13] FIG. 10 is a diagram showing an example of the operation of the surgical robot system according to one embodiment. [Figure 14] FIG. 10 is another diagram showing an example of the operation of the surgical robot system according to the embodiment. [Figure 15] FIG. 10 is yet another diagram showing an example of the operation of the surgical robot system according to one embodiment. [Figure 16] 1 is a schematic diagram illustrating a virtual model of a robot arm and reference sites used in a control method for a surgical robot system according to one embodiment. FIG. [Figure 17] 1 is a flowchart illustrating a control method for a surgical robot system according to one embodiment. [Figure 18] FIG. 2 is a schematic diagram for explaining a control method of a surgical robot system according to one embodiment. [Figure 19] FIG. 10 is another schematic diagram for explaining the control method of the surgical robot system according to one embodiment. [Figure 20] FIG. 10 is yet another schematic diagram for explaining a control method of a surgical robot system according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0039] Hereinafter, embodiments embodying the present disclosure will be described.

[0040] The surgical robot system according to this embodiment is a robot system composed entirely of master-slave manipulators. The operating device constituting the master unit is provided with a hand control that allows the operator (the surgeon who is performing the operation) to manually manipulate its position and orientation. The coordinates of the hand control's position and orientation in a coordinate system set on the master side (master coordinates) are mapped to the coordinates of its position and orientation in a coordinate system set on the slave side (slave coordinates). Scaling can also be introduced in the mapping between the master coordinates and the slave coordinates. For example, a scaling coefficient can be set so that the amount of change in the slave coordinates is smaller than the amount of change in the master coordinates.

[0041] When the operator operates the hand control, the master coordinates change, and the slave coordinates change accordingly. The control device of the surgical robot system calculates the axis values ​​of each of the multiple drive axes of the robot arm of the surgical robot that makes up the slave unit from the slave coordinates (position and posture). The control device controls the operation of the drive axes of the slave unit based on the axis values ​​calculated.

[0042] In this specification, the drive shaft of a robot arm may be a joint of the robot arm, or may be a drive shaft provided on the robot arm to drive a joint (driven shaft) included in a surgical instrument.

[0043] The robot arm of the surgical robot in the surgical robot system according to this embodiment has redundancy. That is, the number of degrees of freedom required for the task to be accomplished by the robot arm is fewer than the degrees of freedom (i.e., the number of drive axes) the robot arm has. Conversely, the degrees of freedom of the robot arm are greater than the degrees of freedom necessary for the task. The degrees of freedom required for the task to be accomplished by the robot arm are typically the degrees of freedom necessary for (the task of) controlling the position and orientation of a surgical instrument detachably attached to the tip of the robot arm. Here, the number of drive axes, which determines the degrees of freedom of the robot arm, includes the number of drive axes for controlling the joints of the surgical instrument itself (the joints of the movable part of the surgical instrument) attached to the tip of the robot arm, and / or the number of drive axes for rotating the entire surgical instrument relative to the tip of the robot arm.

[0044] When the robot arm of the surgical robot that constitutes the slave unit has redundancy, the solution (combination of multiple axis values) for finding each axis value of the robot arm from the slave coordinates by inverse kinematics calculation cannot be determined uniquely, and there are an infinite number of solutions. As a result, it is not possible to determine each axis value of the robot arm, and as it is, it is not possible to control the operation of the robot arm.

[0045] When a robot arm has redundancy, there are extra axes that do not necessarily need to be operated from the perspective of accomplishing a task. Such extra axes can be called redundant axes. Since the robot arm as a whole has an extra number of axes, a specific axis among the multiple axes that make up the robot arm is not necessarily determined as a redundant axis. In other words, in inverse kinematics calculations for a robot arm with redundancy, which axis is treated as a redundant axis is not a given condition that is necessarily determined by the configuration of the robot arm, but is something that must be determined ex post.

[0046] In the control method for the surgical robot system according to this embodiment, one drive axis is assigned to one redundant degree of freedom in the robot arm, and the drive axis to which this redundant degree of freedom is assigned is positioned as the redundant axis. For example, if the number of degrees of freedom required to control the position and orientation of a surgical instrument is n and the number of degrees of freedom (number of drive axes) of the robot arm is n+3, then the robot arm has three redundant degrees of freedom. In this case, three drive axes are selected as redundant axes from the n+3 drive axes of the robot arm, and each of the selected three drive axes is assigned to one of the three redundant degrees of freedom. The degrees of freedom required to control the position and orientation of the surgical instrument are, for example, six degrees of freedom related to the movement of an end effector attached to the tip of the shaft of the surgical instrument in three-dimensional space (e.g., inside the patient's body).

[0047] Furthermore, when the shaft of a surgical instrument is inserted into a port member (trocar or cannula) placed on the surface of the patient's body, a center of rotation (pivot point) for the tilting movement of the shaft of the surgical instrument, which tilts along with the port member, may be set. In this case, the movement of the surgical instrument must be controlled so that the longitudinal axis of the shaft of the surgical instrument always passes through or near the center of rotation (pivot point). This increases the number of degrees of freedom (n) required to control the position and orientation of the surgical instrument by two, for a total of eight.

[0048] In this specification, the term "shaft" refers to a member or section that constitutes the entire or part of a surgical instrument, and is an elongated section or section having a longitudinal axis. Shafts of surgical instruments include those that include joints and those that are flexible.

[0049] In the control method for the surgical robot system according to this embodiment, constraints are added for each redundant degree of freedom possessed by the robot arm. The robot arm in this embodiment has multiple redundant degrees of freedom, and multiple constraints are set accordingly. Furthermore, in this embodiment, among the multiple drive axes of the robot arm, drive axes equal in number to the number of redundant degrees of freedom are selected as redundant axes, and one constraint is set for each redundant axis. While actual drive axes and redundant axes may correspond one-to-one, this is not a requirement. For example, the relationship between the axis values ​​of two drive axes can also be treated as a redundant axis. As a specific example, if the axis value of one drive axis is θ1 and the axis value of the other drive axis is θ2, the θ defined by the constraint equation θ1 + θ2 = θ can be considered as the axis value of a new (virtual) redundant axis. A constraint, for example, constrains the operation of the redundant axis corresponding to that constraint in relation to the configuration of the robot arm, which is determined by the combination of the axis values ​​of the multiple drive axes of the robot arm. That is, the constraint conditions impose restrictions on the configuration of the robot arm, and the operation of the redundant axis corresponding to the constraint conditions is controlled so that the change in the configuration of the robot arm falls within the range restricted by the constraint conditions. This point will be described in detail later with reference to Figure 13 etc.

[0050] By providing multiple constraints in the control of the robot arm in this manner, in this embodiment, which includes a robot arm with multiple redundant axes, a definite solution can be calculated when calculating the axis values ​​(joint variable values) of the drive axes of the robot arm from the position and orientation of the end effector of the surgical instrument. In other words, in this embodiment, once the position and orientation of the end effector of the surgical instrument are determined, the axis values ​​(joint variable values) of the redundant axes are uniquely determined by the constraints. For example, the constraints can be configured as mathematical expressions that uniquely determine the axis values ​​of the redundant axes based on the position and orientation of the end effector. Since the axis values ​​of the redundant axes can be determined by the constraints in this manner, inverse kinematic calculations similar to those used when no redundant axes exist can be applied to multiple drive axes other than the redundant axes. The axis values ​​of the redundant axes can also be referred to as joint positions or joint angles.

[0051] The constraint conditions for redundant axes are also related to which of the multiple drive axes (multiple joints) of a robot arm is treated as a redundant axis. In other words, the content of the constraint conditions for redundant axes may change depending on which of the multiple drive axes of a robot arm is selected as a redundant axis. Furthermore, the constraint conditions for redundant axes can be determined from the perspective of avoiding interference between arms, etc. For example, the constraint conditions for redundant axes can be set so that the robot arm operates within a range of motion where interference between arms is unlikely to occur.

[0052] As described above, the constraint conditions for the redundant axes can be determined from the viewpoint of avoiding interference between the arms, but the content of the constraint conditions determined is not always optimal. For example, when performing a certain surgery, even if an appropriate arm interference avoidance effect can be achieved in one phase of the surgery, the originally intended arm interference avoidance effect may not necessarily be achieved in another phase of the surgery.

[0053] Therefore, in this embodiment, the constraint conditions of the redundant axes are not positioned as fixed conditions that are not changed once they are set, but can be dynamically changed according to the situation at any given time, even during surgery. That is, in this embodiment, the constraint conditions of the redundant axes that are set, for example, before the start of surgery (at the time of setup, etc.) can be dynamically changed according to the situation at any given time after the start of surgery, for example, during the following operation by the operator (surgeon).

[0054] When the constraint conditions of the redundant axis are changed, the axis values ​​of the multiple drive axes (joints) of the robot arm change accordingly. That is, the axis values ​​of the multiple drive axes of the robot arm are calculated by arithmetic processing based on command values ​​for the position and orientation of the end effector generated based on operation input from the operating device, and this arithmetic processing includes content related to the constraint conditions of the redundant axis. Therefore, when the constraint conditions of the redundant axis are changed, the content of the arithmetic processing when calculating the axis values ​​of the multiple drive axes (joints) of the robot arm from the command values ​​for the position and orientation of the end effector changes, and the axis values ​​of the multiple drive axes obtained as a result of the arithmetic processing also change.

[0055] Here, the operation of the robot arm's drive axes related to the constraints of the redundant axes does not affect the motion of the end effector. Therefore, even if the axis values ​​of the multiple drive axes of the robot arm change due to a change in the constraints of the redundant axes, the motion of the end effector is not affected. If the axis values ​​of the multiple drive axes of the robot arm change due to a change in the constraints of the redundant axes, the configuration of the robot arm changes accordingly. The configuration of a robot arm can be defined as the spatial region occupied by the robot arm in an absolute coordinate system (or a world coordinate system). Therefore, by changing the constraints of the redundant axes, the spatial region occupied by the robot arm in the absolute coordinate system can be changed. The change in the spatial region occupied by the robot arm due to a change in the constraints of the redundant axes can be realized without affecting the motion of the end effector. In other words, by changing the constraints of the redundant axes, the spatial region occupied by the robot arm can be changed without affecting the motion of the end effector.

[0056] As described above, the shape of the robot arm can be changed to change its occupied spatial area without affecting the movement of the end effector. Therefore, for example, if there is a possibility that the arms will come close to each other and interfere with each other while an operator (practitioner) is operating the control device to perform treatment (during a so-called following operation), the control device can dynamically change the constraint conditions of the redundant axis, thereby preventing the arms from interfering with each other in advance, without interrupting the operator's treatment (i.e., without interrupting the following operation).

[0057] If interference between the arms occurs and the surgical robot stops, it is necessary to release the surgical robot from its stopped state (locked state) while considering the safety of the patient. For example, it may be necessary to withdraw the surgical instrument from the port member, reconfigure the robot arm to the appropriate shape, and then reattach the surgical instrument to the robot arm before releasing the stopped state of the surgical robot. Once the surgical robot stops due to interference between the arms, releasing the arm takes time and effort, interrupting the surgery during that time. In contrast, this embodiment can prevent interference between the arms in advance, thereby reliably preventing the surgical robot from stopping and the subsequent interruption of the surgery due to the need for recovery. Thus, this embodiment reliably ensures the continuity of the surgery by the operator in a surgery using a surgical robot system.

[0058] A surgical robot system and a control method thereof according to this embodiment will be described below with reference to the drawings.

[0059] As shown in FIGS. 1 to 3, a surgical robot system 10 according to this embodiment includes a surgical robot 1 constituting at least a part of the slave unit, and an operating device 2 constituting at least a part of the master unit. The operating device 2 is placed beside an operating table 111 in an operating room. The operating device 2 may be placed at a location further away from the operating table 111 in the operating room, or may be placed outside the operating room. An operator (surgeon) S who performs surgery using the surgical robot system 10 is positioned on the operating device 2 side, not the surgical robot 1 side, during the procedure in order to operate the operating device 2. A patient P on whom surgery is to be performed is placed on the operating table 111 placed beside the surgical robot 1.

[0060] The operator S inputs operation inputs to the operation device 2 to control the position and posture of the surgical instrument 40. The operation inputs input to the operation device 2 are transmitted to the arm control unit 28 of the surgical robot 1 via a wired or wireless connection. The arm control unit 28 generates operation commands for the surgical robot 1 based on the operation inputs input to the operation device 2. The surgical robot 1 is operated based on these operation commands. In this way, the operation device 2 constitutes an interface between the surgical robot system 10 and the operator S, and is a device (master unit) for remotely operating the surgical robot 1 (slave unit).

[0061] The operation device 2 includes left and right operation manipulators 20A and 20B, multiple operation pedals 22, a touch panel 23, and a monitor 24. The monitor 24 is supported by a support arm 25. The touch panel 23 is disposed on a support bar 26. The operation manipulators 20A and 20B include left and right hand controls 21A and 21B that an operator operates with their left and right hands to input operation commands. The operation manipulators 20A and 20B are operation tools that accept operation inputs for generating movement commands for the position and posture of the surgical instrument 40. The operation pedal 22 is an operation tool that accepts commands such as zooming the endoscopic camera, switching control modes, and switching between robot arms 3 (3A, 3B, 3C, 3D) associated with the left and right operation manipulators 20A and 20B.

[0062] The monitor 24 is a scope-type display device that displays images captured by an endoscope inserted into the body of the patient P. The monitor 24 may also be a 3D viewer that displays 3D images. The support arm 25 can support the monitor 24 so that its height is aligned with the face of the operator S. A sensor 27 that detects the head of the operator S is provided near the monitor 24. For example, the arm control unit 28 is configured so that remote control of the surgical robot 1 by the operating device 2 is possible only when the head of the operator S is detected by the sensor 27, but remote control of the surgical robot 1 by the operating device 2 is not possible when the head of the operator S is not detected by the sensor 27. The operator S operates the hand controls 21A and 21B of the operating manipulators 20A and 20B and the operating pedals 22 while visually checking the affected area of ​​the patient P on the monitor 24.

[0063] The surgical robot 1 constitutes an interface between the surgical robot system 10 and the patient P. The surgical robot 1 is placed in the operating room beside the operating table 111 on which the patient P lies. The operating table 111 and its surrounding area in the operating room are sterilized to form a sterile field.

[0064] The surgical robot 1 includes a positioner 7, an arm base 5 attached to the tip of the positioner 7, and a plurality of robot arms 3 (3A, 3B, 3C, 3D) detachably attached to the arm base 5.

[0065] As shown in FIG. 4, in this embodiment, four robot arms 3A, 3B, 3C, and 3D are attached to an arm base 5. The number of installed robot arms 3 may be less than four or more than four. The tip end 32 (see FIG. 8) of each of the multiple robot arms 3 includes an instrument holder 36 to which a surgical instrument 40 is detachably attached (see also FIG. 9). In other words, the instrument holder 36 constitutes at least a part of the tip end 32 of the robot arm 3.

[0066] The positioner 7 is configured, for example, by a seven-axis vertical articulated robot. The positioner 7 includes a base 90 and a series of links 91 whose base ends are connected to the base 90. The links 91 are connected to each other by joints 92. The base 90 of the positioner 7 is attached to the upper surface of a casing 71 of a movable carriage 70. An arm base 5 is provided at the tip of the positioner 7. The positioner 7 is configured to move the position and orientation of the arm base 5 three-dimensionally. That is, the positioner 7 can move the position of the arm base 5 three-dimensionally relative to the movable carriage 70 along mutually orthogonal X-, Y-, and Z-axis directions, and can rotate the orientation of the arm base 5 around the roll axis, pitch axis, and yaw axis.

[0067] The arm base 5 comprises an arm base main body 50, a positioner mounting section 51 provided on the back surface of the arm base main body 50 and to which the tip end of the positioner 7 is attached, and a plurality of arm mounting sections 52 provided on the lower part of the arm base main body 50 and to which the base ends 80 of a plurality of robot arms 3 are attached. The arm base 5 is configured to be rotatable relative to the tip end of the positioner 7. The arm base 5 is provided with an imaging section 53. The imaging section 53 can capture an image of at least one of the operating table 111 and the patient P placed on the operating table 111.

[0068] The positioner 7, the arm base 5, and the members from the base end 80 of the robot arm 3 to the instrument holder 36 of the robot arm 3 are covered with a sterile drape (not shown). These members from the base end 80 of the robot arm 3 to the instrument holder 36 are shielded from the sterile field in the operating room.

[0069] 5 shows a forceps assembly 40A as an example of a surgical instrument 40. The forceps assembly 40A includes a shaft portion 43, an end effector 44 including a pair of jaws provided at the tip of the shaft portion 43, and an instrument base 45 that holds the base end of the shaft portion 43 rotatably about the longitudinal axis of the shaft portion 43.

[0070] 6 shows an endoscope assembly 40B, which is an imaging device that is inserted into a patient's body to capture images of the condition of the surgical site, as another example of a surgical instrument 40. The endoscope assembly 40B includes an endoscope 12 and an endoscope holder 13. The endoscope holder 13 holds the endoscope 12 rotatably about its longitudinal axis. A drive unit (not shown) is provided inside the endoscope holder 13 for rotating the endoscope 12 about its longitudinal axis. The front portion (camera side portion) of the endoscope 12 is formed as a shaft portion 43.

[0071] As described above, the shaft portion 43 of the surgical instrument 40 may refer to an elongated member having the end effector 44 at its tip, or may refer to the front portion (camera side portion) of the endoscope 12 formed as an elongated member.

[0072] The instrument base 45 of the forceps assembly 40A is provided with a locking portion (not shown) that releasably locks to the instrument holder 36 of the robot arm 3, and the instrument holder 36 is provided with a receiving portion (not shown) to which the locking portion locks. For example, the locking portion and the receiving portion have complementary shapes, and a retractable portion that resiliently protrudes and retracts on one of the locking portion and the receiving portion is releasably locked in a recessed portion on the other of the locking portion and the receiving portion. For example, a surgical assistant can manually release the resiliently locked recessed portion to remove the forceps assembly 40A from the instrument holder 36. The endoscope holder 13 also has an attachment / detachment mechanism similar to that described above, and can be attached to and detached from the instrument holder 36 by manual operation by a surgical assistant.

[0073] In the surgical robot 1 of this embodiment, an endoscope assembly 40B is detachably held as a surgical instrument 40 in the instrument holder 36 of one of the multiple (four in this example) robot arms 3. A surgical instrument other than the endoscope assembly 40B, for example, a forceps assembly 40A, is detachably held as a surgical instrument 40 in the instrument holders 36 of the remaining (three in this example) robot arms 3. In the surgical robot 1 shown in Figure 4, the endoscope assembly 40B is attached to the second robot arm 3B, and surgical instruments other than the endoscope assembly 40B, for example, a forceps assembly 40A, are attached to the first, third, and fourth robot arms 3A, 3C, and 3D.

[0074] In the surgical robot 1, the arm base 5 functions as a "hub" that serves as a base for multiple robot arms 3. Although the positioner 7 in this embodiment is configured as a vertical articulated robot, the positioner 7 may also be configured as a manipulator other than a vertical articulated robot. For example, the positioner 7 may be a linear rail for supporting the arm base 5, an elevator device, or a bracket attached to the ceiling or wall. In this embodiment, the base 90 of the positioner 7 is attached to the movable cart 70. However, instead, the base of the positioner 7 may be attached to a fixed object such as the wall or floor of the operating room or a member fixed to these.

[0075] The cart 70 is also provided with an operation unit 72 for mainly setting and inputting the positions and postures (preparatory postures) of the positioner 7, arm base 5, and multiple robot arms 3 before treatment. The operation unit 72 includes, for example, a touch panel.

[0076] In the above-described surgical robot 1, multiple components are connected in series from the positioner 7 to the surgical instrument 40. In this specification, the end of the above-described series of components that faces the positioner 7 (more specifically, the base 90 of the positioner 7) may be referred to as the "base end (of the series of components)," and the opposite end may be referred to as the "distal end (of the series of components)."

[0077] The arm control unit 28, which controls the operation of the surgical robot 1 based on operation input from the operating device 2, may be composed of a single controller for centralized control, or may be composed of multiple controllers for distributed control in cooperation with each other. As shown in FIG. 7, the arm control unit 28 is composed of a computer 300 such as a microcontroller. The computer 300 has a processor 301 such as a CPU, a memory 302 such as a ROM and a RAM, an I / O unit (input / output unit) 303, and an interface 304. The memory 302 stores a control program and various data used to control the operation of the surgical robot 1. The interface 304 is used for communication with the operating device 2 and various sensors (such as an encoder that detects the rotation angle of a servo motor, which will be described later).

[0078] FIG. 8 shows the schematic configuration of one robot arm 3 among the multiple robot arms 3 included in the surgical robot 1. A surgical instrument 40 is detachably attached to the tip 32 of the robot arm 3. In this embodiment, the multiple robot arms 3 included in the surgical robot 1 all have the same or similar configurations, but at least one of the multiple robot arms 3 may have a different configuration (e.g., different degrees of freedom) from the other robot arms 3. As shown in FIG. 8, the robot arm 3 includes an arm main body 30 and a translational movement mechanism 35 provided on the arm main body 30. The translational movement mechanism 35 has an instrument holder 36 movably provided on its main body. The translational movement mechanism 35 (including the instrument holder 36) forms at least a part of the tip 32 of the robot arm 3. As shown in FIGS. 8 and 9, an instrument base 45 of a surgical instrument 40 is detachably attached to the instrument holder 36 by an attachment / detachment mechanism (not shown). The tip end 32 of the robot arm 3 is movable three-dimensionally relative to the base end 80 of the robot arm 3 .

[0079] 9 and 10, the instrument holder 36 of the translational movement mechanism 35 is equipped with an arm manual operation mechanism 39. The arm manual operation mechanism 39 has a command input unit 39A including a button, a joystick, etc., and a manual controller 39B that drives the translational movement mechanism 35 in response to commands input from the command input unit 39A. The commands input from the command input unit 39A include, for example, a command related to a retraction operation for retracting the surgical instrument 40 inserted in the port member 112 to a retracted position. An assistant surgeon near the surgical robot 1 may operate the command input unit 39A to control the retraction operation of the surgical instrument 40 using the manual controller 39B.

[0080] The arm main body 30 includes a base end 80 that is detachably attached to the arm base 5, and a plurality of arm link sections that are sequentially connected from the base end 80 to the tip end. The arm main body 30 includes a plurality of joint sections (a plurality of drive shafts) that are sequentially connected so that one arm link section rotates relative to another arm link section. The arm link sections include a first link 81 to a sixth link 86. The joint sections include a first joint J31 to a seventh joint J37. Note that, although the joint sections (the first joint J31 to the seventh joint J37) of the arm main body 30 in this embodiment are configured as rotary joints equipped with rotary shafts, at least some of the joint sections may be configured as linear joints.

[0081] More specifically, a base end portion of a first link 81 is connected to the tip side of a base end portion 80 of the robot arm 3 via a first joint J31 (base end torsion joint), which is a torsion (roll) joint. A base end portion of a second link 82 is connected to the tip end portion of the first link 81 via a second joint J32, which is a bending (pitch) joint. A base end portion of a third link 83 is connected to the tip end portion of the second link 82 via a third joint J33, which is a torsion joint. A base end portion of a fourth link 84 is connected to the tip end portion of the third link 83 via a fourth joint J34, which is a bending joint. A base end portion of a fifth link 85 is connected to the tip end portion of the fourth link 84 via a fifth joint J35, which is a torsion joint. A base end portion of a sixth link 86 is connected to the tip end portion of the fifth link 85 via a sixth joint J36, which is a bending joint. The base end of the translation mechanism 35 is connected to the tip end of the sixth link 86 via a seventh joint J37 (tip side bending joint) which is a bending joint.

[0082] In this embodiment, the first link 81 has a bent shape between the adjacent joints J31 and J32. In other words, the first link 81 is configured so that the rotation axis of the first joint J31 and the rotation axis of the second joint J32 do not intersect. That is, the first link 81 has a first portion 81a and a second portion 81b. Of these, the first portion 81a extends from the first joint J31 on the base end side in a predetermined first direction (the direction of the rotation axis of the first joint J31). Furthermore, the second portion 81b extends from the tip end of the first portion 81a in a second direction intersecting the extension direction of the first portion 81a (and perpendicular to the rotation axis of the second joint J32) and is connected to the second joint J32 on the tip end side. The angle between the first direction and the second direction of the first link 81 is, for example, 120 degrees or more and 160 degrees or less (for example, 140 degrees). The first portion 81a and the second portion 81b are smoothly connected, which makes it easier to pass wires such as electrical wiring through the arm link portions even if some of the arm link portions have a bent shape.

[0083] Furthermore, the fourth link 84 has a bent shape between the adjacent joints J34 and J35, and this portion forms the elbow 11 of the arm main body 30. In other words, the fourth link 84 is configured so that the rotation axis of the fourth joint J34 and the rotation axis of the fifth joint J35 do not intersect. The rotation axis of the fifth joint J35 is offset from the rotation axis of the fourth joint J34 in a direction perpendicular to the rotation axes of the fourth joint J34 and the fifth joint J35. That is, the fourth link 84 has a first portion 84a and a second portion 84b. Of these, the first portion 84a extends from the fourth joint J34 on the base end side in a predetermined first direction (a direction perpendicular to both the rotation axis of the fourth joint J34 and the rotation axis of the fifth joint J35). The second portion 84b extends from the distal end of the first portion 84a in a second direction (the direction of the rotation axis of the fifth joint J35) that intersects with the extension direction of the first portion 84a, and is connected to the distal-side fifth joint J35. The angle between the first direction and the second direction of the fourth link 84 is, for example, 70 degrees or more and 110 degrees or less (for example, 90 degrees). The first portion 84a and the second portion 84b are smoothly connected.

[0084] The other links 82, 83, 85, and 86 are formed in a straight line between adjacent joints. In other words, the other links 82, 83, 85, and 86 are configured so that the rotation axes of adjacent joints intersect with each other.

[0085] Each arm link section is configured so that the cross-sectional area perpendicular to the longitudinal direction is smaller than that of the arm link section (or base end 80) connected to the base end side of that arm link section. As a result, the arm main body 30 is configured to gradually become thinner from the base end 80 toward the tip end. Furthermore, each of the joints J32, J34, and J36, which are bending joints, is configured so that the tip end of the base end side arm link section 81, 83, and 85 is located on one side of the rotation axis direction with respect to the center of the joint section in the rotation axis direction. Also, the base end of the tip end side arm link section 82, 84, and 86 is configured so that it faces the tip end of the base end side arm link section 81, 83, and 85 on the other side of the rotation axis direction with respect to the center of the joint section in the rotation axis direction.

[0086] Furthermore, the width in the rotational axis direction at the joint, i.e., the distance between the outer end of the tip of the arm link parts 81, 83, 85 on the base end side and the outer end of the rotational axis direction at the base end of the arm link parts 82, 84, 86 on the tip end side, is shorter than the diameter (maximum dimension) of the cross section perpendicular to the longitudinal direction of the part located closer to the base end than the tip of the arm link parts 81, 83, 85 on the base end side.

[0087] In this way, each joint and the arm link portion at its distal end are configured to be narrower than the arm link portion at its proximal end, which increases the range of movement of each arm body 30 (the range where it does not interfere with other arm bodies 30) in a workspace that becomes narrower as it approaches the treatment site 110 of the patient P.

[0088] The outer shell of the arm body 30 is made of a material that is painted to be chemical resistant. In addition, openings such as inspection holes in the arm body 30 are covered with resin covers. By forming the covers from a material such as resin, it is possible to reduce the weight of parts that do not contribute to the strength of the arm body 30. This makes it possible to reduce the impact even if the cover falls or the arm body 30 hits another arm body 30 or a treatment assistant. Note that the outer shell of the arm body 30 itself may include a portion made of a resin material.

[0089] The translational movement mechanism 35 is a mechanism that can translate the surgical instrument 40 attached to the instrument holder 36 in the extension direction of the shaft portion 43 by translating the instrument holder 36, which is movably provided in the main body portion of the translational movement mechanism 35, in the longitudinal axis direction Dt (Figure 8).

[0090] The translational movement mechanism 35 is connected to the distal end of the sixth link 86 of the arm body 30 via a seventh joint J37, which is a bending joint. The seventh joint J37 extends in a direction perpendicular to the longitudinal axis direction Dt. A drive mechanism including a drive source for translationally moving the instrument holder 36 is provided inside the translational movement mechanism 35. The translational movement mechanism 35 can advance the surgical instrument 40 in the insertion direction and retract the surgical instrument 40 in the withdrawal direction. The drive mechanism provided inside the translational movement mechanism 35 may be configured, for example, using a pulley and timing belt, or may be a mechanism including a gear train, or may be configured as a double-speed mechanism. In this way, the translational movement mechanism 35 forms an eighth joint J38, which is a linear joint that moves the instrument holder 36 linearly in the longitudinal axis direction Dt.

[0091] The instrument holder 36 detachably holds an instrument base 45 of the surgical instrument 40. As shown in Fig. 10, the instrument holder 36 includes an instrument driver 38 having a plurality of (four in this example) drive shafts 37 that are rotationally driven to apply a driving force to the surgical instrument 40. One of the plurality of drive shafts 37 of the instrument driver 38 generates a driving force that rotates the shaft portion 43 of the surgical instrument 40 about its longitudinal axis.

[0092] As shown in FIG. 5, a forceps assembly 40A, which is one of the surgical instruments 40, has an instrument base 45 provided at its proximal end, a shaft portion 43 whose proximal end is connected to the instrument base 45, and an end effector (treatment tool) 44 connected to the distal end of the shaft portion 43. Furthermore, the forceps assembly 40A is equipped with a drive force transmission portion (not shown) that is connected to a drive shaft 37 of an instrument drive unit 38 included in the instrument holder 36 by attaching the forceps assembly 40A to the instrument holder 36 and transmits the drive force of the drive shaft 37. The instrument drive unit 38 of the instrument holder 36 is provided with, for example, four drive shafts 37, and these drive shafts 37 are used, for example, for opening and closing a pair of jaws that are the end effector 44 of the forceps assembly 40A ( FIG. 5 ), for pitching or yawing the end effector 44, and for rolling the shaft portion 43 of the forceps assembly 40A around its longitudinal axis relative to the instrument base 45.

[0093] When the surgical instrument 40 attached to the instrument holder 36 is the endoscope assembly 40B shown in Figure 6, the drive shaft 37 of the instrument drive unit 38 of the instrument holder 36 drives a drive unit (not shown) provided inside the endoscope holder 13, thereby rotating the endoscope 12 around the longitudinal axis of its shaft portion 43.

[0094] The surgical instrument 40 has a defined longitudinal axis direction Dt (see FIG. 8 ), and the instrument base 45, shaft portion 43, and end effector 44 are arranged along the longitudinal axis direction Dt, in this order. The end effector of the surgical instrument 40 is not limited to the end effector 44 consisting of a pair of jaws shown in FIG. 5 . That is, the end effector of the surgical instrument 40 can be selected from a group including, for example, instruments with a moving joint (e.g., forceps, scissors, graspers, needle holders, microdissectors, staple appliers, tackers, suction and irrigation tools, snare wires, clip appliers, etc.) and instruments without a joint (e.g., cutting blades, cauterizing probes, irrigators, catheters, suction orifices, etc.).

[0095] The base end of the shaft 43 is connected to the instrument base 45 via a ninth joint J39 (tip-side torsion joint), which is a torsion (roll) joint. The rotation axis R9 of the ninth joint J39 has a rotation axis that is arranged coaxially with the central axis C of the shaft 43. The central axis C of the shaft 43 corresponds to the longitudinal axis of the surgical instrument 40. The rotation axis of the joint is the geometric (imaginary) axis of the rotating shaft. As described above, in this embodiment, the instrument base 45 and the ninth joint J39 may be elements included in the robot arm 3 for positioning the shaft portion 43.

[0096] As described above, the eighth joint J38 located between the seventh joint J37 and the ninth joint J39 is a translatory joint, and therefore the orientation of the rotation axis R9 of the ninth joint J39 relative to the rotation axis R7 of the seventh joint J37 is fixed. The rotation axis R7 of the seventh joint J37 is perpendicular to a reference plane RP ( FIG. 8 ) that includes the rotation axis R9 of the ninth joint J39 and extends in the longitudinal direction Dt. That is, in this embodiment, the seventh joint J37 constitutes a bending joint that defines the reference plane RP. The angle between the rotation axis R7 and the reference plane RP is not limited to a right angle; it is sufficient that the rotation axis R7 and the reference plane RP intersect. By rotating the seventh joint J37, the shaft portion 43 can be swung in an upright or downward direction.

[0097] 11, in this embodiment, a plurality of (four in this example) arm attachment parts 52 are provided on the arm base 5 in accordance with a plurality of (four in this example) robot arms 3. The arm base 5 has an elongated shape having a longitudinal axis, and the plurality of arm attachment parts 52 are arranged side by side in the longitudinal direction of the arm base 5 (the direction indicated by D1 in FIG. 11). By fixing the base ends 80 of the plurality of robot arms 3 to the plurality of arm attachment parts 52, respectively, the first link 81, which is the link on the side of the base end part 80 of the plurality of robot arms 3, is configured to be relatively rotatable around the rotation axis of the first joint J31.

[0098] Specifically, the arm attachment parts 52 are arranged such that the base ends 80 of the robot arms 3 are aligned in a predetermined first direction D1. The first direction D1 is a direction set on (included in) a predetermined first plane P1. In this embodiment, the first plane P1 is a virtual plane parallel to the floor (horizontal plane) G when the arm base 5 is positioned at the ready position (see FIG. 3 ). The first direction D1 is, for example, a horizontal direction that is the direction of the longitudinal axis of the elongated arm base 5, but is not limited to this. The first direction D1 is also a direction perpendicular to the rotation axis R1 of a first joint J31 (described later) of the robot arm 3. That is, the arm attachment parts 52 are aligned in a row in the first direction D1 (the direction into the depth of the paper in FIG. 3 ) when viewed from above with the arm base 5 positioned at the ready position, and face a second direction D2 that is perpendicular to the first direction D1. The arrangement of the arm attachment parts 52 is not limited to a single row, and they may be aligned in two rows. In addition, some of the arm attachment portions 52 may be offset in the second direction D2. In addition, some of the arm attachment portions 52 may be offset in the third direction D3. The third direction D3 is, for example, the vertical direction (the direction perpendicular to the paper surface in FIG. 11).

[0099] In the above, the instrument base 45 and the ninth joint J39 of the surgical instrument 40 have been described as components included in the surgical instrument 40, but these instrument base 45 and the ninth joint J39 can also be components included in the robot arm 3.

[0100] 12 is a block diagram showing a schematic configuration example of a control system of the surgical robot system 10. The arm body 30 of the robot arm 3 is provided with, corresponding to each joint J31 to J37 of the arm body 30, drive servomotors (denoted as SM in FIG. 12) M31 to M37, encoders (denoted as EN in FIG. 12) E31 to E37 that detect the rotation angles of the servomotors M31 to M37, and reducers (not shown) that reduce the speed of the outputs of the servomotors M31 to M37 to increase the torque.

[0101] 12 representatively shows the first joint J31 and the seventh joint J37 of the arm main body 30 out of the joints J31 to J37, and omits the control systems for the other joints J32 to J36. Furthermore, the translational movement mechanism 35 is provided with a servo motor M38 (a servo motor that drives an interlocking mechanism) for translational movement of the eighth joint J38, a servo motor M39 for rotational movement of the ninth joint J39, encoders E38 and E39 that detect the rotation angles of the servo motors M38 and M39, and reducers (not shown) that reduce the speed of the outputs of the servo motors M38 and M39 to increase the torque.

[0102] The encoders E31 to E39 are provided as an example of a rotational position detection means for detecting the rotational positions (rotation angles) of the servo motors M31 to M39, and a rotational position detection means such as a resolver may be used instead of the encoders E31 to E39.

[0103] The arm control unit 28 includes a control unit main body 29 that controls the movement of the multiple robot arms 3 based on operation commands. Servo control units C31 to C39, indicated by SC in the figure, are electrically connected to the control unit main body 29, and multiple actuators related to the servo motors M31 to M39 are electrically connected via amplifier circuits or the like.

[0104] In the above configuration, a position and orientation command for the tip 32 of the robot arm 3 is input to the control unit main body 29 based on an operation input input to the operation device 2 during treatment. The control unit main body 29 generates and outputs a position command value based on the position and orientation command and the rotation angle detected by the encoders E31 to E39. The servo control units C31 to C39, which have acquired this position command value, generate and output a drive command value (torque command value) based on the rotation angle detected by the encoders E31 to E39 and the position command value. The amplifier circuit, which has acquired this drive command value, supplies a drive current corresponding to the drive command value to the servo motors M31 to M39. In this way, each of the servo motors M31 to M39 is servo-controlled so that the tip 32 of the robot arm 3 reaches a position and orientation corresponding to the position and orientation command.

[0105] The arm control unit 28 is also provided with a storage unit 31 in the control unit main body 29 from which data can be read, and which stores in advance surgery information input via the operation device 2. This surgery information includes the combination of multiple robot arms 3 used in the surgery.

[0106] The memory unit 31 also stores information such as the length along the longitudinal axis direction Dt of the surgical instrument 40 held at the tip 32 of the robot arm 3. This enables the control unit main body 29 to grasp the position of the tip (end effector 44) of the surgical instrument 40 held at the tip 32 of the robot arm 3 based on the position and orientation command for the tip 32 of the robot arm 3. The position of the tip of the surgical instrument 40 is sometimes called the tool center point (TCP).

[0107] Furthermore, the memory unit 31 stores in advance predetermined preparation positions (for example, the respective positions and postures of the positioner 7, arm base 5, and robot arm 3 shown in FIG. 3) that are established before treatment of the arm base 5 and the multiple robot arms 3. The memory unit 31 can store multiple preparation positions according to the content (type) of treatment, the treatment area, etc. The above-mentioned predetermined preparation positions are sometimes called setup positions.

[0108] Figures 13 to 15 are diagrams for explaining an example of the operation of the surgical robot system 10. In Figures 13 and 14, of the four robot arms 3, robot arm 3B and elements related to robot arm 3B are shown, with other elements being omitted as appropriate. Also, in Figure 15, of the four robot arms 3, robot arm 3A and elements related to robot arm 3A are shown, with other elements being omitted as appropriate.

[0109] 1 to 3, in surgery using the surgical robot 1, first, the surgical assistant (or the operator S himself / herself) uses the cart 70 to move the surgical robot 1 near the operating table 111. At this time, the positioner 7, arm base 5, and multiple robot arms 3 are located in predetermined storage positions set for the cart 70.

[0110] Port members 112, such as trocars or cannulas, are placed on the body surface of a patient P lying on an operating table 111, for example, lined up side by side in a straight line. In Fig. 3, the port members 112 are arranged in a line in the depth direction of the page. However, the arrangement of the multiple port members 112 is not limited to this arrangement.

[0111] Then, the positioner 7 is controlled to position the arm base main body 50 so that the arm base main body 50 is located above the patient P and the rotation axis R1 of the first joint J31 of the robot arm 3 attached to the arm attachment part 52 faces in a generally horizontal direction. The angle between the rotation axis R1 of the first joint J31 and the horizontal plane is within a range of, for example, minus 30 degrees to plus 30 degrees. Furthermore, the positioner 7 is controlled to position the arm base main body 50 so that the second direction D2, which is the direction in which the arm attachment part 52 faces, is generally perpendicular to the direction in which the multiple port members 112 are lined up.

[0112] The surgical assistant then performs the task of setting, in the arm control unit 28, a remote center RC (predetermined center point) that is associated with each robot arm 3 in a one-to-one correspondence. In this task, the surgical assistant attaches, for example, a teaching surgical instrument 40 to the instrument holder 36 and moves the teaching surgical instrument 40 so that the tip of the teaching surgical instrument 40 is positioned at the center of the hole in the port member 112. The surgical assistant then inputs an instruction to set the remote center RC into the operation unit 72. In response to this, the arm control unit 28 performs a forward transformation based on the posture of the robot arm 3 at that time, the positional relationship of the tip of the shaft portion 43 of the teaching surgical instrument 40 relative to the instrument base 45, the position and posture of the base end portion 80, and information related to the parameters of each arm link portion, to calculate the position of the remote center RC.

[0113] The robot arms 3 and the port members 112 are associated in a one-to-one correspondence so that the remote centers RC associated with each robot arm 3 are aligned in the order of the robot arms 3 in the first direction D1. That is, the robot arm 3A, which is the first from the right in the first direction D1, is associated with the port member 112, which is the first from the right in the first direction D1. Then, by calculating the remote center RC of this port member 112, the robot arm 3A is associated with the remote center RC, which is the first from the right in the first direction D1. The same applies to the other robot arms 3B, 3C, and 3D.

[0114] Then, the surgical assistant or operator S replaces the teaching surgical instrument 40 with a surgical instrument 40 such as a forceps assembly 40A or an endoscope assembly 40B. By performing such a preliminary operation, the positioner 7, the arm base 5, and the multiple robot arms 3 are positioned so that the port member 112 placed on the body surface of the patient P, which is the treatment site 110, and the surgical instruments 40 attached to each robot arm 3 have a predetermined initial positional relationship.

[0115] In this initial posture, the robot arm 3 has a base end 80 that extends generally horizontally. The second link 82 and the third link 83 that are connected to the bent first link 81 extend diagonally downward. More specifically, the second link 82 and the third link 83 extend downward in a direction from the base end side of the base end 80 toward the tip end side (toward the toes of the patient P on the operating table 111) in the direction in which the rotation axis R1 of the first joint J31 extends (second direction D2). The fourth link 84, the fifth link 85, and the sixth link 86 turn back at the elbow 11 and extend diagonally downward. More specifically, the fourth link 84, the fifth link 85, and the sixth link 86 extend downward in a direction from the tip end side of the base end 80 toward the base end side (toward the head side of the patient P on the operating table 111) in the direction in which the rotation axis R1 of the first joint J31 extends.

[0116] In this embodiment, the arm control unit 28 does not accept operations from the operation device 2 while the surgical robot 1 (positioner 7, arm base 5, and multiple robot arms 3) moves from the storage position to the preparation position. After the surgical robot 1 reaches the preparation position, the arm control unit 28 becomes able to accept operations from the operation device 2. During surgery after the surgical robot 1 reaches the preparation position, the arm control unit 28 generates operation commands based on operation input generated by the operator S operating the operation device 2 while, in principle, the positioner 7 and arm base 5 are stationary. The arm control unit 28 then controls the operation of each robot arm 3 in accordance with the operation command generated based on the operation input from the operation device 2, thereby appropriately changing the position and posture of the surgical instrument 40. At this time, the arm control unit 28 controls the robot arm 3 by restricting the posture of the surgical instrument 40 so that the shaft 43 of the surgical instrument 40 inserted into the port member 112 passes through the remote center RC. This restricts the port member 112 from moving in the plane of the patient P's body surface.

[0117] The operation of moving the surgical instrument 40 to a target position and assume a target posture during the surgical procedure is realized, for example, by an operation including the operation of joints including nine axes, i.e., joints J31 to J39. In this way, the robot arm 3 has more degrees of freedom than are necessary to control the position and posture of the surgical instrument 40. In other words, the robot arm 3 has redundancy. Therefore, a set of rotational positions (joint positions) of the multiple joints of the robot arm 3 corresponding to a certain target position and target posture of the shaft 43 of the surgical instrument 40 (or the configuration of the robot arm 3 determined by a set of these angular positions) is not uniquely determined. For example, the operation of rotating the shaft 43 in a circumferential direction about its central axis C can be realized not only by rotating the ninth joint J39, which is provided coaxially with the central axis C, but also by rotating the distal end 32 of the arm body 30 in a circumferential direction about the central axis C. Therefore, the arm control unit 28 combines the movement of the arm main body 30 and the movement of the ninth joint J39 to control the rotational movement of the shaft unit 43 in the circumferential direction about the central axis C. The arm control unit 28 then operates the arm main body 30 and the ninth joint J39 to satisfy the following constraints among the movements that can be made to rotate the shaft unit 43 in the circumferential direction about the central axis C or to maintain the shaft unit 43 at the same circumferential position without rotating it.

[0118] In setting the constraint conditions, as shown in FIG. 13, first, the arm control unit 28 sets a reference point RD for each robot arm 3. As shown in FIG. 11, the reference point RDB of the robot arm 3B is located on a reference line RLB, which is an extension of the rotation axis R1 of the first joint J31 of the robot arm 3B. The reference point RDA of the robot arm 3A is located on a reference line RLA, which is offset to one side (positive direction) of the first direction D1 (direction perpendicular to the rotation axis R1) with respect to the rotation axis R1 of the first joint J31 of the robot arm 3A (see also FIG. 15). In this operation example, the first direction D1 is also the horizontal direction. The first direction D1 is parallel to the longitudinal direction of the arm base 5. The reference point RDC of the robot arm 3C is located on a reference line RLC, which is offset to the other side (negative direction) of the first direction D1 with respect to the rotation axis R1 of the first joint J31 of the robot arm 3C. Furthermore, the reference point RDD of the robot arm 3D is located on a reference line RLD that is offset to the other side (negative direction) of the first direction D1 with respect to the rotation axis R1 of the first joint J31 of the arm 3D. The offset distance of the reference line RL of each robot arm 3 is set to an individual value. This makes it possible to appropriately prevent interference with other devices in the surgical robot system 10, such as an adjacent robot arm 3, and with the surrounding environment, such as assistants.

[0119] Next, as shown in FIG. 14 , the arm control unit 28 determines whether the length L of a perpendicular line vh from the reference point RD to the central axis C of the shaft unit 43, which will assume the target posture at the target position, is shorter than a predetermined lower limit length Lmin. If the arm control unit 28 determines that the length of the perpendicular line vh is shorter than the lower limit length Lmin, it moves the position of the reference point RD on the reference line RL in a direction away from the central axis C of the shaft unit 43 so that the length of the perpendicular line vh becomes longer than the predetermined length Lmin. Note that if the arm control unit 28 determines that the length of the perpendicular line vh is longer than the lower limit length Lmin, it does not execute this process. Note that the arm control unit 28 may determine the position of the reference point RD on the reference line RL based on a continuous function that defines the relationship between the length L of the perpendicular line vh and the position of the reference point RD on the reference line RL, without performing the above determination.

[0120] 13, the arm control unit 28 positions the joints J31 to J39 so that the reference plane RP passes through the reference point RD. As described above, the reference plane RP is a plane that includes the rotation axis R9 of the ninth joint J39 extending in the longitudinal direction Dt and intersects with the rotation axis R7 of the seventh joint J37.

[0121] This restricts the orientation of the translational movement mechanism 35 and the instrument base 45 so that they swing around the axis Rv connecting the reference point RD and the remote center RC. Therefore, when rotating the shaft portion 43 in a circumferential direction about its central axis C, the proportion of the operation of rotating the tip portion 32 of the robot arm 3 in a circumferential direction about the central axis C can be reduced. Furthermore, the proportion of the operation of rotating the shaft portion 43 by rotating the ninth joint J39 can be increased. This allows the translational movement mechanism 35, which is connected perpendicularly to the seventh joint J37, to assume an orientation facing outward from the reference point RD. This prevents the translational movement mechanism 35 and the instrument base 45 from assuming an orientation that protrudes to the side of the robot arm 3 (in the first direction D1). As a result, interference with other devices in the surgical robot system 10, such as the adjacent robot arm 3, and the surrounding environment can be prevented. Furthermore, since the robot arm 3 can be made to assume a posture in which the sixth link 86 of the arm main body 30 faces from the seventh joint J37 toward the center of the robot arm 3, the link length of the arm main body 30 can be used effectively, widening the range of motion. Furthermore, since multiple robot arms 3 assume a posture in which they spread out in a fan shape from the arm base main body 50, interference between adjacent robot arms can be reduced.

[0122] Furthermore, as shown in FIG. 14 , for example, when the shaft 43 swings about the remote center RC and approaches the reference point RD, the radius of rotation of the distal end 32 of the robot arm 3 around the central axis C during the operation of rotating the shaft 43 around the central axis C decreases. As a result, the movement of the robot arm 3 becomes sensitive, and large vibrations and reduced tracking performance may occur in the translational movement mechanism 35 and the instrument base 45 due to the sudden movement of the robot arm 3. In this regard, when the arm control unit 28 determines that the length L of the perpendicular line vh is shorter than the lower limit length Lmin, it moves the position of the reference point RD on the reference line RL so that the length of the perpendicular line vh is longer than the predetermined length Lmin. Therefore, it is possible to prevent the radius of rotation of the distal end 32 of the robot arm 3 around the central axis C from becoming smaller when the shaft 43 approaches the reference point RD, thereby suppressing sensitive movement of the robot arm 3. Furthermore, when the arm control unit 28 determines the position of the reference point RD on the reference line RL based on a continuous function that defines the relationship between the length L of the perpendicular line vh and the position of the reference point RD on the reference line RL, the occurrence of hypersensitive movements can be avoided.

[0123] In this way, the arm control unit 28 controls the robot arm 3 so that the shaft 43 of the surgical instrument 40 assumes the target posture at the target position. When a new target position and target posture are set, the arm control unit 28 again determines whether the length L of the perpendicular line vh is shorter than the predetermined lower limit length Lmin, and then executes the subsequent processes.

[0124] In addition to the control method described above, the surgical robot system 10 according to this embodiment can implement the control method described below to more reliably avoid interference between the robot arm 3 and surrounding objects (e.g., an adjacent robot arm 3).

[0125] In this embodiment, at least a portion of each of the multiple robot arms 3 is modeled. For example, as shown in FIG. 16, the robot arm 3 may be modeled so that at least a portion of the robot arm 3 is surrounded by a capsule-shaped virtual model. The target portion of the robot arm 3 to be modeled may include at least a portion of the translational movement mechanism 35. At least a portion of the virtual model of the robot arm 3 is set as a reference portion. In FIG. 16, the reference portion is represented by a capsule indicated by a solid line. The reference portion may be a portion that is assumed to be most likely to come close to adjacent robot arms 3 during treatment. For example, a portion of the translational movement mechanism 35 may be selected as the reference portion.

[0126] 17, the arm control unit 28 determines (step S1) a proximity distance between reference portions of the virtual models of, for example, adjacent robot arms 3. For example, the arm control unit 28 determines a proximity distance between a reference portion of the virtual model of a first robot arm 3A and a reference portion of the virtual model of a second robot arm 3B.

[0127] Next, the arm control unit 28 determines whether the difference between the proximity distance determined in step S1 and the allowable minimum distance is equal to or greater than a predetermined threshold (step S2). Fig. 18 shows a situation in which the difference between the proximity distance d12 between the reference portion of the first robot arm 3A and the reference portion of the second robot arm 3B and the allowable minimum distance is smaller than the predetermined threshold, and the difference between the proximity distance d23 between the reference portion of the second robot arm 3B and the reference portion of the third robot arm 3C and the allowable minimum distance is greater than the predetermined threshold.

[0128] When the arm control unit 28 determines that the difference between the proximity distance between the arms and the minimum allowable distance is smaller than a predetermined threshold, it selects the robot arm 3 to be adjusted (step S3). As the robot arm 3 to be adjusted, for example, from the pair of robot arms 3 whose proximity distances have been determined, the robot arm that is operating by operation (following operation) based on operation input from the operation device 2 is selected.

[0129] By targeting the operating robot arm 3 as the adjustment target, the operating range of the operating robot arm 3 can be expanded. In other words, if adjustment is not performed, the operating robot arm 3 must, for example, stop its operation to prevent interference with other robot arms when the proximity distance to other robot arms becomes smaller than the minimum allowable distance. In contrast, by targeting the operating robot arm 3 as the adjustment target, it becomes possible to continue the operation to control the position and orientation of the surgical instrument 40 while avoiding interference with other robot arms.

[0130] Furthermore, for example, if a first robot arm 3A in operation approaches a second robot arm 3B at rest, causing the proximity distance between the arms to become smaller than the minimum allowable distance, attempting to increase the proximity distance between the first robot arm 3A by adjusting the configuration of the second robot arm 3B at rest may result in a decrease in the proximity distance between the second robot arm 3B to be adjusted and the adjacent third robot arm 3C. In this case, it may become necessary to adjust the configuration of the third robot arm 3C as an additional adjustment target. This chain reaction of increasing the number of robot arms to be adjusted is desirable, if possible, from the perspective of preventing the complexity of control. In this regard, by adjusting the first robot arm 3A in operation rather than the second robot arm 3B at rest, it is possible to prevent a chain reaction of increasing the number of robot arms to be adjusted.

[0131] Furthermore, by adjusting the robot arm 3 while it is in operation, the possibility of vibration occurring in the robot arm 3 due to adjustment can be reduced compared to when the robot arm 3 is adjusted while it is stationary, and the impact of vibration on the surgery can be suppressed.

[0132] Note that when both of the pair of robot arms 3 are operating, the robot arm operating in the direction that shortens the proximity distance may be selected. Also, when both robot arms 3 are operating in directions that bring them closer to each other, the following processing can also be performed. First, a virtual line is assumed that connects the reference locations of the virtual models of the pair of robot arms 3. The velocity vector components in the direction along this virtual line are calculated for each of the pair of robot arms 3. When the calculated value of the velocity vector component of one robot arm 3 is larger than the calculated value of the velocity vector component of the other robot arm 3, the robot arm 3 with the larger calculated value is selected as the robot arm 3 to be adjusted.

[0133] Next, the arm control unit 28 determines the adjustment direction of the offset of the reference point RD for the robot arm 3 selected in step S3 (step S4). That is, it determines whether the offset of the reference point RD for the selected robot arm 3 should be adjusted in the plus direction or the minus direction in the first direction D1 shown in FIG.

[0134] Specifically, the offset adjustment direction is determined by moving the robot arm 3 to be adjusted on the model. That is, the reference point RD is slightly shifted in either the positive or negative direction in the first direction D1 on the model to slightly change the offset amount. This slightly changes the constraint condition for the ninth joint J39, which is set as a redundant axis. As a result, the configuration of the robot arm 3 to be adjusted changes slightly on the model. This slightly changes the proximity distance between the arms on the model (see FIG. 19 ). If the change in the proximity distance between the arms on the model when the reference point RD is slightly shifted in the positive direction in the first direction D1 is a change in a direction that increases the proximity distance, that direction, i.e., the positive direction in the first direction D1, is determined as the adjustment direction. On the other hand, if the change in the proximity distance between the arms on the model when the reference point RD is slightly shifted in the positive direction in the first direction D1 is a change in a direction that decreases the proximity distance, the opposite direction, i.e., the negative direction in the first direction D1, is determined as the adjustment direction for the offset amount. It should be noted that the direction in which the reference point RD is initially moved on the model can be set to the minus direction instead of the plus direction described above.

[0135] In the calculation processing on the model in step S4 described above, only calculations are performed regarding the joint position of the ninth joint J39, which changes based on changes in the offset amount of the reference point RD, and this can be done with a small amount of calculation and requires only a short calculation time.

[0136] Alternatively, the processing in step S4 can be performed by actually moving the robot arm 3. That is, in actual control, not on a model, the reference point RD is slightly shifted in either the positive or negative direction in the first direction D1 to slightly change the offset amount. This slightly changes the constraint condition for the ninth joint J39, which is set as a redundant axis. As a result, the instrument driver 38 of the instrument holder 36 is driven, causing the ninth joint J39 to rotate slightly. The slight rotation of the ninth joint J39 slightly changes the configuration of the robot arm 3 to be adjusted. This slightly changes the proximity distance between the arms. If the change in the proximity distance between the arms when the reference point RD is slightly shifted in the positive (or negative) direction in the first direction D1 is a change in the direction that increases the proximity distance, the positive (or negative) direction in the first direction D1 is determined to be the adjustment direction. On the other hand, if the change in the proximity distance between the arms when the reference point RD is slightly shifted in the plus (or minus) direction in the first direction D1 results in a change in the direction that reduces the proximity distance, the minus (or plus) direction in the first direction D1 is determined as the adjustment direction for the offset amount. Note that even when the robot arm 3 is actually moved in step S4, it is the redundant axis (ninth joint J39) that is driven, and therefore the movement of the surgical instrument 40, which is controlled based on the operation input from the operating device 2, is not affected.

[0137] Once the offset adjustment direction is determined in step S4, the offset of the reference point RD in the first direction D1 is adjusted in the determined adjustment direction (step S5). Adjusting (changing) the offset of the reference point RD changes the constraint condition for the ninth joint J39, which is set as a redundant axis. As a result, the instrument driver 38 of the instrument holder 36 is driven to rotate the ninth joint J39. At this time, the movement of the surgical instrument 40, which is controlled based on the operation input from the operating device 2, is not affected. As the ninth joint J39 rotates due to the change in the constraint condition, the configuration of the robot arm 3 to be adjusted changes, thereby increasing the proximity distance between the arms.

[0138] Next, it is determined whether the difference between the proximity distance between the arms, which has increased due to the adjustment of the offset amount of the reference point RD, and the allowable minimum distance is equal to or greater than a predetermined threshold (step S6). When the difference between the proximity distance between the arms and the allowable minimum distance is equal to or greater than the predetermined threshold, the adjustment of the offset amount of the reference point RD is terminated (step S6).

[0139] As described above, by adjusting the offset amount of the reference point RD, the arm control unit 28 controls the instrument driving unit 38 of the instrument holder 36 to rotate the ninth joint J39 so as to maintain the proximity distance between the robot arms 3 at or above the minimum allowable distance. As described above, since the ninth joint J39 is set as a redundant axis, even if the constraint conditions are changed in accordance with a change in the offset amount of the reference point RD and the ninth joint J39 is rotationally driven as a result, this can be prevented from affecting the movement of the surgical instrument 40.

[0140] 20 shows how interference between the third robot arm 3C and the fourth robot arm 3D is avoided by the control method according to the present embodiment described above. In the example shown in FIG. 20, while the fourth robot arm 3D is stationary, the third robot arm 3C moves in a direction approaching the fourth robot arm 3D (step t). The arm control unit 28 determines the proximity distance between the reference portion of the third robot arm 3C and the reference portion of the fourth robot arm 3D based on the 3D virtual model of the robot arm 3C (see FIG. 16) (step S1 in FIG. 17). As the third robot arm 3C approaches the fourth robot arm 3D, the proximity distance between the reference portion of the model of the third robot arm 3C and the reference portion of the model of the fourth robot arm 3D gradually decreases (step t+1).

[0141] When the third robot arm 3C approaches the fourth robot arm 3D and the difference between the proximity distance and the allowable minimum distance between the reference portions of the models of both robots becomes equal to or less than a threshold, the arm control unit 28 starts the process of adjusting the offset amount of the reference point RD of the third robot arm 3C (step t+2). Specifically, first, the arm control unit 28 selects the robot arm whose offset amount is to be adjusted (step S3 in FIG. 17). In the example shown in FIG. 20, the fourth robot arm 3D is stationary and the third robot arm 3C is moving, so the arm control unit 28 selects the moving third robot arm 3C as the adjustment target.

[0142] Next, the arm control unit 28 calculates the adjustment direction for the offset amount of the third robot arm 3C selected as the adjustment target (step S4 in FIG. 17). Specifically, the offset of the third robot arm 3C on the model is slightly moved in one direction (for example, the positive direction) in the first direction D1 shown in FIG. 15, and if this increases the proximity distance between the reference portion of the third robot arm 3C and the reference portion of the fourth robot arm 3D on the model, the one direction (positive direction) is determined as the adjustment direction for the offset amount. Conversely, if the proximity distance decreases, the other direction (negative direction) in the first direction D1 is determined as the adjustment direction for the offset amount of the third robot arm 3C.

[0143] Next, the offset amount of the third robot arm 3C is adjusted in the calculated adjustment direction (step S5 in FIG. 17). As a result, the third robot arm 3C moves in a direction away from the fourth robot arm 3D (step t+2). The arm control unit 28 determines whether the proximity distance between the reference portions of the model of the third robot arm 3C and the model of the fourth robot arm 3D is equal to or greater than the allowable minimum distance (step S6 in FIG. 17), and ends adjustment of the offset amount of the third robot arm 3C when the proximity distance is equal to or greater than the allowable minimum distance.

[0144] Through the above operations, the proximity distance between the reference locations of the model of the third robot arm 3C and the model of the fourth robot arm 3D is maintained at or above the minimum allowable distance. This makes it possible to automatically avoid interference between the third robot arm 3C and the fourth robot arm 3D. As a result, for example, it is possible to avoid the surgical robot 1 being put into a stopped state (locked state) due to interference between the robot arms, thereby ensuring the continuity of the surgery.

[0145] Furthermore, the proximity distance between the reference regions of the adjacent robot arms 3C and 3D models is automatically maintained at or above the minimum allowable distance by the arm control unit 28, so that the control of the position and posture of the end effector by the operating robot arm 3C (following operation) can be prevented from being interrupted. This ensures the continuity of the treatment by the operator S.

[0146] As described above, the object to be avoided from interference is typically the adjacent robot arm 3. However, by providing an appropriate object detection means, other devices other than the robot arm 3 that constitute the patient-side unit, or treatment assistants, etc., can also be included as interference avoidance targets. An example of an appropriate object detection means is a proximity sensor 60 (see FIG. 8 ) provided at an appropriate position on the robot arm 3 to detect the proximity of surrounding objects. Examples of the proximity sensor 60 include an inductive proximity sensor, a magnetic proximity sensor, an optical proximity sensor, an ultrasonic proximity sensor, and a capacitive proximity sensor. The detection signal from the proximity sensor 60 is transmitted to the arm control unit 28, which determines the distance between the target robot arm 3 and the surrounding object based on the detection signal. The above-described interference avoidance control can be performed based on the determined distance. Alternatively, an imaging device for capturing images of surrounding objects may be provided, and the images from the imaging device may be analyzed using artificial intelligence techniques such as machine learning to determine the distance between the target robot arm 3 and the surrounding object.

[0147] Furthermore, for objects other than the robot arm 3 that are targets for interference avoidance, a spatial region in which the object exists or a spatial region in which the object may exist may be modeled in advance as a no-entry region. The no-entry region may be set, for example, to a spatial region in which devices other than the robot arm 3 constituting the surgical robot 1 exist, or to a spatial region in which the body of a surgical assistant may be present during surgery. The model of the no-entry region may be defined in a slave-side coordinate system recognized by the arm control unit 28. This allows the arm control unit 28 to determine the proximity distance between the model of the target robot arm 3 and the model of the no-entry region by calculation without using a proximity sensor or the like. Alternatively, a method using the detection results of a proximity sensor and a method using the model of the no-entry region may be used in combination.

[0148] As described above, the surgical robot system and control method according to this embodiment can reliably avoid interference between the robot arm and objects around the robot arm, thereby ensuring the continuity of surgery by the operator (surgeon) S. The control method for the surgical robot system according to this embodiment can be implemented by a computer program. The computer program may include computer code configured to instruct a computer to perform one or more functions of the control method. The computer program and / or code for executing such a control method may be provided on one or more computer-readable media. The computer-readable medium may be either transient or non-transitory. The computer-readable medium may be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, or a propagation medium for data transmission, for example, for downloading code via the Internet. Alternatively, the computer-readable medium may take the form of one or more physical computer-readable media, such as a semiconductor or solid-state memory, a magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk, or an optical disk such as a CD-ROM, a CD-R / W, or a DVD.

[0149] Additionally, the functions of the components disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, application-specific integrated circuits (ASICs), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuitry. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or processor. [Explanation of symbols]

[0150] 1. Surgical robot 2 Control device 3, 3A, 3B, 3C, 3D Robot Arm 10. Surgical Robot System 28 Arm control unit (control device) 32 Tip of the robot arm 35 Translation mechanism 36 Instrument holder 40 Surgical instruments 38 Instrument drive unit 43 Shaft of surgical instrument 60 Proximity Sensor C. Central axis of the shaft (longitudinal axis of the surgical instrument) J31~J39 Joints (drive shafts) R1~R9 rotation axis RC Remote Center RD reference point RL, RLA, RLB reference line RP reference plane S Operator (operator) Patient P

Claims

1. a robot arm having a distal end portion to which a surgical instrument having a longitudinal axis can be attached, and a plurality of drive shafts, the number of the plurality of drive shafts being greater than a minimum number of degrees of freedom required to control the position and orientation of the surgical instrument; an operating device that receives an operation input from an operator to control the position and posture of the surgical instrument; a control device that controls the robot arm based on the operation input, the distal end portion has an instrument drive portion that rotates at least a portion of the surgical instrument about the longitudinal axis; The control device controls the instrument driving unit to maintain a proximity distance between the robot arm and an object present around the robot arm at or above an allowable minimum distance.

2. 2. The surgical robot system of claim 1, wherein the control device operates the instrument driver to rotate at least a portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance when the difference between the proximity distance and the allowable minimum distance becomes smaller than a predetermined threshold.

3. the proximity distance is the distance between a reference portion of the robot arm and the object; the robotic arm has a translation mechanism that moves the surgical instrument along the longitudinal axis; The surgical robot system according to claim 1 or 2, wherein the reference site includes at least a part of the translational movement mechanism.

4. at least a portion of the surgical instrument is configured to be inserted through a port member provided in a patient; 3. The surgical robot system of claim 1, wherein the number of the plurality of drive axes of the robot arm is greater than a minimum number of degrees of freedom required to control the position and orientation of the surgical instrument with at least a portion of the surgical instrument inserted through the port member.

5. The surgical robot system according to claim 1 or 2, wherein the control device determines the proximity distance based on an arm model generated by modeling at least a portion of the robot arm.

6. The surgical robot system of claim 5, wherein the control device operates the robot arm on the arm model to determine, of two rotation directions about the longitudinal axis of the at least part of the surgical instrument, a rotation direction that increases the proximity distance.

7. the robotic arm has a translation mechanism that moves the surgical instrument along the longitudinal axis; The surgical robot system of claim 5 , wherein the at least a portion of the robot arm is at least a portion of the translation mechanism.

8. the object is another robotic arm to which another surgical instrument can be attached; the operating device receives an operation input from the operator for controlling the position and posture of the surgical instrument attached to the robot arm and the position and posture of the other surgical instrument attached to the other robot arm; The surgical robot system according to claim 1 or 2, wherein the control device controls the robot arm and the other robot arm based on the operation input.

9. the other robot arm has a distal end portion to which the other surgical instrument having a different longitudinal axis can be attached, and a plurality of drive shafts, the number of the plurality of drive shafts being greater than the minimum degree of freedom required to control the position and orientation of the other surgical instrument; the distal end of the other robot arm has a different instrument drive unit that rotates at least a portion of the other surgical instrument around the different longitudinal axis; The surgical robot system according to claim 8 , wherein the control device adjusts the proximity distance by operating at least one of the instrument driving unit and the other instrument driving unit.

10. 10. The surgical robot system according to claim 9, wherein the control device selects, from among the robot arm and the other robot arm, a robot arm that is operating by the operation input, as a robot arm to be adjusted, and adjusts the proximity distance by operating an instrument driving unit of the robot arm to be adjusted.

11. The surgical robot system according to claim 1 or 2, further comprising the surgical instrument provided at the tip of the robot arm.

12. the robot arm has a base end, a torsion joint disposed at the base end, and a bending joint disposed between the tip end and the base end, The control device Controlling the robot arm to intersect a rotation axis of the bending joint with a reference plane including the longitudinal axis, and fixing an orientation of the rotation axis of the bending joint with respect to the reference plane; A predetermined center point is set, and a reference point is set on a reference line that is an extension line of a rotation axis of the torsion joint or a line that is offset in a direction perpendicular to the extension line, and the robot arm is controlled to position the longitudinal axis at the center point and the reference plane at the reference point; 3. The surgical robot system according to claim 1, wherein the offset amount of the reference point in the direction perpendicular to the extension line is adjusted to control the direction and amount of movement of the instrument driving unit, thereby maintaining the proximity distance at or above the minimum allowable distance.

13. The surgical robot system according to claim 12 , wherein the direction perpendicular to the extension line is a horizontal direction.

14. an arm base for holding the base end of the robot arm and a base end of another robot arm, the arm base having a longitudinal axis; The surgical robot system of claim 12 , wherein the orthogonal direction of the extension line is parallel to the longitudinal axis of the arm base.

15. A control method for a surgical robot system, the surgical robot system comprising: a robot arm having a distal end portion to which a surgical instrument having a longitudinal axis is attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than a minimum degree of freedom required to control the position and orientation of the surgical instrument; an operation device that receives an operation input from an operator to control the position and orientation of the surgical instrument; and a control device that controls the robot arm based on the operation input, Rotating at least a portion of the surgical instrument around the longitudinal axis by an instrument driver that configures at least a portion of the distal end portion; A method for controlling a surgical robot system, the method controlling the instrument driving unit to maintain a proximity distance between the robot arm and an object present around the robot arm at or above an allowable minimum distance.

16. 16. The control method for a surgical robot system according to claim 15, wherein, when the difference between the proximity distance and the allowable minimum distance becomes smaller than a predetermined threshold, the instrument driving unit is operated to rotate at least the portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance.

17. A computer-readable medium storing computer-readable instructions, which, when executed by a processor of a surgical robot system, cause the processor to execute a control method for the surgical robot system, the surgical robot system comprising: a robot arm having a distal end portion to which a surgical instrument having a longitudinal axis is attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than a minimum degree of freedom required to control the position and orientation of the surgical instrument; an operation device that receives an operation input from an operator to control the position and orientation of the surgical instrument; and a control device that controls the robot arm based on the operation input, the control method comprising: Rotating at least a portion of the surgical instrument around the longitudinal axis by an instrument driver that configures at least a portion of the distal end portion; A computer-readable medium for controlling the tool driver to maintain a proximity distance between the robotic arm and objects surrounding the robotic arm at or above an acceptable minimum distance.

18. 18. The computer-readable medium of claim 17, wherein the control method operates the instrument driver to rotate the at least part of the surgical instrument about the longitudinal axis in a direction that increases the proximity distance when a difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold.

19. a robot arm having a distal end to which a surgical instrument can be attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than the minimum number of degrees of freedom required to control the position and orientation of the surgical instrument; an operating device that receives an operation input from an operator to control the position and posture of the surgical instrument; a control device that controls the robot arm based on the operation input, The control device defining at least one of the plurality of drive shafts as a redundant drive shaft, and controlling the redundant drive shaft based on the operation input and constraint conditions; A surgical robot system that adjusts the constraint conditions to maintain a proximity distance between the robot arm and an object present around the robot arm at or above an allowable minimum distance.

20. the surgical instrument has a longitudinal axis; 20. The surgical robotic system of claim 19, wherein the redundant drive shaft rotates at least a portion of the surgical instrument about the longitudinal axis.

21. 21. The surgical robot system of claim 20, wherein the control device rotates the at least a portion of the surgical instrument about the longitudinal axis in a direction that increases the proximity distance when a difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold.

22. A control method for a surgical robot system, the surgical robot system comprising: a robot arm having a distal end to which a surgical instrument is attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than the minimum degrees of freedom required to control the position and orientation of the surgical instrument; an operation device that receives an operation input from an operator to control the position and orientation of the surgical instrument; and a control device that controls the robot arm based on the operation input, defining at least one of the plurality of drive shafts as a redundant drive shaft, and controlling the redundant drive shaft based on the operation input and constraint conditions; A method for controlling a surgical robot system, which adjusts the constraint conditions to maintain a proximity distance between the robot arm and an object present around the robot arm at or above an allowable minimum distance.

23. the surgical instrument has a longitudinal axis; 23. The method of claim 22, wherein the redundant drive shaft rotates at least a portion of the surgical instrument about the longitudinal axis.

24. 24. The method of claim 23, further comprising rotating at least a portion of the surgical instrument around the longitudinal axis in a direction that increases the proximity distance when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold.

25. A computer-readable medium storing computer-readable instructions, which, when executed by a processor of a surgical robot system, cause the processor to execute a control method for the surgical robot system, the surgical robot system comprising: a robot arm having a distal end to which a surgical instrument is attached and a plurality of drive shafts, the number of the plurality of drive shafts being greater than a minimum degree of freedom required to control the position and orientation of the surgical instrument; an operation device that receives an operation input from an operator to control the position and orientation of the surgical instrument; and a control device that controls the robot arm based on the operation input, the control method comprising: defining at least one of the plurality of drive shafts as a redundant drive shaft, and controlling the redundant drive shaft based on the operation input and constraint conditions; A computer-readable medium that adjusts the constraint to maintain a proximity distance between the robot arm and objects surrounding the robot arm at or above a minimum allowable distance.

26. the surgical instrument has a longitudinal axis; 26. The computer readable medium of claim 25, wherein the control method causes the redundant drive shafts to rotate at least a portion of the surgical instrument about the longitudinal axis.

27. 27. The computer-readable medium of claim 26, wherein the control method rotates the at least part of the surgical instrument about the longitudinal axis in a direction that increases the proximity distance when a difference between the proximity distance and the minimum acceptable distance becomes less than a predetermined threshold.

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