Surgical robot system and control method therefor

Abstract

The present invention comprises: a robot arm (3) that has a tip portion to which a surgical instrument (40) having a longitudinal axis (C) can be attached, and a plurality of drive shafts; an operation device (2) that receives an operation input from an operator (S) for controlling the position and posture of the surgical instrument (40); and a control device (28) that controls the robot arm (3) on the basis of the operation input. The control device (28): controls, in a state where a part of the surgical instrument (40) is inserted into the body of a patient through an opening formed in the body of the patient, the robot arm (3) on the basis of the operation input while maintaining a state where the longitudinal axis (C) passes through a pivot point (RC); and, when the operation of the robot arm (3) is restricted and thus the operation range of the surgical instrument (40) is reduced, moves a set position of the pivot point (RC) in a direction in which at least a part of the restriction on the operation of the robot arm (3) is canceled and the operation range of the surgical instrument (40) is expanded. The reduction in operation range of a surgical instrument due to restriction of the operation of the robot arm can be prevented or alleviated.

Description

Surgical robot system and its control method

[0001] This disclosure relates to a surgical robot system and its control method.

[0002] Conventionally, instead of a surgical method in which a surgeon directly holds and operates a surgical instrument, a surgical robot system for performing a surgical operation by operating a surgical instrument using a robot has been disclosed. The surgical robot system is used, for example, in minimally invasive surgery that can reduce the burden on a patient undergoing surgery.

[0003] The surgical robot system generally includes a surgical robot disposed beside the patient and an operating device for a surgeon to remotely operate the surgical robot. The operating device operated by the surgeon is disposed, for example, inside an operating room where an operating table on which the patient is placed is disposed. The surgical robot has a robot arm, and a surgical instrument is detachably attached to the robot arm. The surgical instrument attached to the robot arm has a configuration that can be inserted into a port member provided on the patient. The port member is, for example, a trocar or a cannula. The types of surgical instruments include forceps, an electric scalpel, a stapler, an endoscope, etc., and are appropriately selected from them according to the surgical procedure and the like. When the surgical robot has a plurality of robot arms, different types of surgical instruments may be attached to each robot arm, or the same type of surgical instrument may be attached to two or more robot arms. For example, an endoscope is attached to one robot arm, and forceps are attached to two or more other robot arms.

[0004] A surgeon (operator) can control the position and orientation of a surgical instrument attached to a robotic arm by operating an operating device to operate a surgical robot. When the surgical instrument itself has movable parts such as joints like forceps, the operation of the movable parts of the surgical instrument can also be performed by the operating device. Thereby, the surgeon can control the position and orientation of the surgical instrument (and also the movable parts if it has movable parts) by the operating device. For example, when the surgical instrument has a configuration in which a pair of jaws is provided at the tip of the shaft portion, 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 operation of the pair of jaws, or the rotational operation around the pitch axis and / or the yaw axis. Also, when the shaft portion itself is configured to be rotatable around its longitudinal axis, the surgeon can perform a rotational operation (operation around the roll axis) of the shaft portion of the surgical instrument by operating the operating device.

[0005] When performing minimally invasive surgery or the like using a surgical robot system, for example, a port member (e.g., a trocar or a cannula) is inserted into an opening formed in the patient's body (particularly the body surface such as the abdominal wall), and the shaft portion of the surgical instrument is inserted into the port member. At least the tip portion of the shaft portion of the surgical instrument extends into the patient's body from the front end opening of the port member. When the control device of the robotic arm operates the shaft portion of the surgical instrument based on the operation of the operating device by the surgeon, it operates the shaft portion of the surgical instrument while maintaining a state in which the longitudinal axis of the shaft portion of the surgical instrument passes through a pivot point set at the patient's opening (see Patent Document 1). Thereby, the movement of the port member inserted through the patient's body surface being pressed by the shaft portion of the surgical instrument is restricted.

[0006] Conventional surgical robot systems typically have robotic arms equipped with multiple drive axes (joints). These multiple drive axes (joints) in the robotic arm generally include rotational joints, and sometimes linear joints. The number of drive axes (joints) in the robotic arm, i.e., the degrees of freedom of the robotic arm, must be at least the same as the degrees of freedom required to control the position and orientation of the surgical instrument. In particular, in minimally invasive surgery, for example, two additional degrees of freedom may be required in the robotic arm to maintain the longitudinal axis of the shaft of the surgical instrument passing through the pivot point.

[0007] WO2024 / 052969A1

[0008] In conventional surgical robot systems, the movement of the surgical robot arms was sometimes restricted due to interference between adjacent robot arms, which reduced the range of motion of the surgical instruments.

[0009] This disclosure is made to solve the problems described above, and one of its purposes is to provide a surgical robot system and a control method thereof that can prevent or mitigate the limitation of the robot arm's movement which reduces the range of motion of surgical instruments.

[0010] (Aspect 1) Aspect 1 of this disclosure is a surgical robot system comprising: a robot arm having a tip portion to which a surgical instrument having a longitudinal axis can be attached and a plurality of drive axes; an operating device for receiving operator input for controlling the position and orientation of the surgical instrument; and a control device for controlling the robot arm based on the operator input, wherein the control device controls the robot arm based on the operator input while maintaining the longitudinal axis passing through a pivot point when a part of the surgical instrument is inserted into the patient's body through an opening formed in the patient's body, and when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the control device moves the pivot point to a position that avoids at least a part of the restriction on the movement of the robot arm and expands the range of motion of the surgical instrument.

[0011] (Aspect 2) Aspect 2 of this disclosure is a surgical robot system according to Aspect 1, wherein when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the direction and amount of movement when moving the set position of the pivot point are determined based on the amount and direction of movement of the tip of the surgical instrument when the robot arm is controlled based on the operation input to move the tip of the surgical instrument.

[0012] (Aspect 3) Aspect 3 of this disclosure is a surgical robot system according to aspect 1 or 2, wherein the situation in which the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced relates to the control of the movement of the robot arm to avoid interference between the robot arm and other objects.

[0013] (Aspect 4) Aspect 4 of this disclosure is the surgical robot system according to aspect 3, further comprising another robot arm different from the robot arm, wherein the other object includes the other robot arm.

[0014] (Aspect 5) Aspect 5 of this disclosure is a surgical robot system according to aspect 4, wherein the control device generates a first arm model by modeling at least a portion of the robot arm and generates a second arm model by modeling at least a portion of the other robot arm, and the situation in which the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced is related to the proximity distance between the first arm model and the second arm model becoming smaller than the minimum allowable distance.

[0015] (Aspect 6) Aspect 6 of this disclosure is a surgical robot system according to any one of aspects 1 to 5, wherein the situation in which the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced is such that the interference margin of the robot arm during operation is below a predetermined threshold, and the direction of movement of the tip of the surgical instrument is such that the interference margin of the robot arm during operation is reduced.

[0016] (Aspect 7) Aspect 7 of this disclosure is a surgical robot system according to any one of aspects 1 to 6, wherein the control device moves the pivot point from an initial setting position when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, and then moves the pivot point in the direction of the initial setting position when the movement of the robot arm is not restricted. (Aspect 8) Aspect 8 of this disclosure is a surgical robot system according to any one of aspects 1 to 7, wherein the control device does not perform the operation of moving the pivot point in the direction of the initial setting position when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced.

[0017] (Aspect 9) Aspect 9 of this disclosure is a surgical robot system according to any one of aspects 1 to 8, wherein the amount of movement of the tip of the surgical instrument by controlling the robot arm based on the operation input is X, the amount of movement of the set position of the pivot point in the direction in which the operating range of the surgical instrument is expanded is Y, the distance from the pivot point to the pivot point is A, and the distance from the pivot point to the tip of the instrument is B, and the following equation Y = X × A / (A + B) is satisfied.

[0018] (Aspect 10) Aspect 10 of this disclosure is a surgical robot system according to aspect 9, wherein the tip of the robot arm has a translational movement mechanism for moving the surgical instrument along the longitudinal axis, and the reference point corresponds to the rear end of the translational movement mechanism.

[0019] (Aspect 11) Aspect 11 of this disclosure is a surgical robot system according to aspect 9, wherein the tip of the robot arm includes a translational movement mechanism for moving the surgical instrument along the longitudinal axis, the plurality of drive axes include a tip-side drive axis that allows the translational movement mechanism to be rotatably moved to another part of the tip of the robot arm, and the reference point corresponds to the tip-side drive axis.

[0020] (Aspect 12) Aspect 12 of this disclosure is a surgical robot system according to any one of aspects 1 to 11, wherein the number of the plurality of drive axes of the robot arm is greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument, the control device defines at least one of the plurality of drive axes as a redundant drive axis, controls the redundant drive axis based on the operation input and constraint conditions, and adjusts the constraint conditions to maintain a proximity distance between the robot arm and objects present around the robot arm that is greater than or equal to the minimum allowable distance.

[0021] (Aspect 13) Aspect 13 of this disclosure is the surgical robot system according to aspect 12, wherein the redundant drive shaft rotates at least a portion of the surgical instrument around the longitudinal axis.

[0022] (Aspect 14) Aspect 14 of this disclosure is a surgical robot system according to aspect 13, 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.

[0023] (Aspect 15) Aspect 15 of this disclosure is a method for controlling a surgical robot system, wherein the surgical robot system comprises a robot arm having a tip portion capable of mounting a surgical instrument having a longitudinal axis and a plurality of drive axes, an operating device that receives operator input for controlling the position and orientation of the surgical instrument, and a control device that controls the robot arm based on the operator input, wherein, when a part of the surgical instrument is inserted into the patient's body through an opening formed in the patient's body, the robot arm is controlled based on the operator input while maintaining the state in which the longitudinal axis passes through a pivot point set in the opening, and when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the setting position of the pivot point is moved in a direction in which at least a part of the restriction on the movement of the robot arm is avoided and the range of motion of the surgical instrument is expanded.

[0024] (Aspect 16) Aspect 16 of this disclosure is a control method for a surgical robot system according to aspect 15, wherein when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the direction and amount of movement when moving the set position of the pivot point are determined based on the amount and direction of movement of the tip of the surgical instrument when the robot arm is controlled based on the operation input to move the tip of the surgical instrument.

[0025] (Aspect 17) Aspect 17 of this disclosure is a computer-readable medium storing computer-readable instructions, wherein when the computer-readable instructions are executed by a processor of a surgical robot system, the processor causes the processor to execute a control method for the surgical robot system, the surgical robot system comprising a robot arm having a tip portion capable of attaching a surgical instrument having a longitudinal axis and a plurality of drive axes, an operating device that receives operator input for controlling the position and orientation of the surgical instrument, and a control device that controls the robot arm based on the operator input, wherein the control method controls the robot arm based on the operator input while maintaining the state that the longitudinal axis passes through a pivot point set in the opening when a part of the surgical instrument is inserted into the patient's body through an opening formed in the patient's body, and when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the computer-readable medium moves the setting position of the pivot point in a direction in which at least a part of the restriction on the movement of the robot arm is avoided and the range of motion of the surgical instrument is expanded.

[0026] (Aspect 18) Aspect 18 of this disclosure is a computer-readable medium according to aspect 17, wherein the direction and amount of movement when moving the set position of the pivot point when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced is determined based on the amount and direction of movement of the tip of the surgical instrument when the robot arm is controlled based on the operation input to move the tip of the surgical instrument.

[0027] The surgical robot system and its control method described herein can prevent or mitigate the limitation of the robot arm's movement, which reduces the range of motion of surgical instruments.

[0028] A perspective view showing the schematic configuration of a surgical robot system according to one embodiment. A plan view showing the schematic configuration of a surgical robot system according to one embodiment. A side view showing the schematic configuration of a surgical robot system according to one embodiment. Another side view showing the schematic configuration of a surgical robot system according to one embodiment. A perspective view showing the schematic configuration of surgical instruments attached to the robot arm of a surgical robot system according to one embodiment. A perspective view showing the schematic configuration of other surgical instruments attached to the robot arm of a surgical robot system according to one embodiment. A schematic block diagram showing the system configuration of the arm control unit of a surgical robot system according to one embodiment. A perspective view showing the schematic configuration of the robot arm and surgical instruments of a surgical robot system according to one embodiment. A perspective view showing the schematic configuration of the tip of the robot arm and surgical instruments attached to the tip of the robot arm of a surgical robot system according to one embodiment. A perspective view showing the schematic configuration of the tip of the robot arm of a surgical robot system according to one embodiment. A diagram showing the schematic configuration of the arm base and the robot arm attached to the arm base of a surgical robot system according to one embodiment. A schematic block diagram showing the configuration of the drive control system of a surgical robot system according to one embodiment. A diagram for explaining the automatic pivot position adjustment function in a surgical robot system according to one embodiment. Another diagram illustrating the automatic pivot position adjustment function in a surgical robot system according to one embodiment. Yet another diagram illustrating the automatic pivot position adjustment function in a surgical robot system according to one embodiment. A flowchart illustrating the automatic pivot position adjustment function in a control method for a surgical robot system according to one embodiment. A diagram illustrating the automatic pivot position adjustment function in a surgical robot system according to one embodiment. Another diagram illustrating the automatic pivot position adjustment function in a surgical robot system according to one embodiment. A schematic diagram showing a virtual model and reference part of a robot arm used in a control method for a surgical robot system according to one embodiment. A diagram illustrating an example of calculating the distance between virtual models of robot arms used in a control method for a surgical robot system according to one embodiment. Another flowchart illustrating the automatic pivot position adjustment function in a control method for a surgical robot system according to one embodiment.Figure 22 shows the state of the surgical robot in a first case illustrating the verification results of the automatic pivot position adjustment function in a control method for a surgical robot system according to one embodiment. Figure 24 shows the verification results of the first case. Figure 26 shows the state of the surgical robot in a second case illustrating the verification results of the automatic pivot position adjustment function in a control method for a surgical robot system according to one embodiment. Figure 28 shows the verification results of the fourth case. Figure 30 shows the verification results of the first case shown in Figure 22. A figure showing the verification results of the third case shown in Figure 26 using the verification method shown in Figure 30. A figure showing the verification results of the fourth case shown in Figure 28 using the verification method shown in Figure 30. A figure showing an example of operation of a surgical robot system according to one embodiment. Another figure showing an example of operation of a surgical robot system according to one embodiment. Yet another figure showing an example of operation of a surgical robot system according to one embodiment. A flowchart schematically showing the control method of a surgical robot system according to one embodiment. A schematic diagram for explaining the control method of a surgical robot system according to one embodiment. Another schematic diagram for explaining the control method of a surgical robot system according to one embodiment. Yet another schematic diagram for explaining the control method of a surgical robot system according to one embodiment.

[0029] The following describes embodiments that embody this disclosure.

[0030] The surgical robot system according to this embodiment is a robot system composed of master-slave type manipulators as a whole. The operating device constituting the master unit is equipped with a hand control that allows the operator (the surgeon performing the procedure) to manually manipulate its position and orientation. The position and orientation coordinates of the hand control in the coordinate system set on the master side (master coordinates) are mapped to the position and orientation coordinates in the 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 factor may be set so that the change in the slave coordinates is smaller than the change in the master coordinates.

[0031] When the operator manually controls the hand controls, the master-side coordinates change, and the slave-side coordinates change accordingly. The control unit 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 constitutes the slave-side unit, based on the slave-side coordinates (position and orientation). Based on the axis values ​​obtained through calculation, the control unit controls the movement of the drive axes of the slave-side unit.

[0032] In this specification, the drive axis of a robot arm may be a joint of the robot arm, or it may be a drive axis provided on the robot arm side to drive a joint (driven axis) included in a surgical instrument.

[0033] In the surgical robot system and its control method according to this embodiment, pivot points are set at the start of surgery in openings formed in the patient's body (particularly the body surface such as the abdominal wall) for inserting port members (e.g., trocars or cannulas). The number of openings formed in the patient's body is, for example, the same as the number of robot arms provided by the surgical robot, and each opening is set as a pivot point. Multiple openings (and multiple pivot points) can be arranged, for example, in a generally straight line. However, the arrangement of multiple openings (and multiple pivot points) is not limited to a straight line; for example, they can be arranged in a zigzag pattern, or they can be arranged to form the vertices of a polygon such as a quadrilateral.

[0034] The robot arm control device controls the robot arm in response to input from the operating device to operate surgical instruments, ensuring that the longitudinal axis of the surgical instrument's shaft passes through the pivot point. Openings formed in a patient's body include artificial openings (incisions) created by making cuts on the body surface using a scalpel, etc., and natural openings (natural orifices) that are originally formed in the human body, such as the anus.

[0035] Furthermore, the surgical robot system and its control method according to this embodiment include a function to dynamically move the pivot point, which is set at the start of the surgery, within an acceptable range during the surgery (especially during the following motion). More specifically, when the robot arm's movement is restricted due to interference with surrounding objects (e.g., adjacent robot arms), thereby reducing the range of motion of the surgical instruments, the robot arm control device moves the pivot point's setting position in a direction that avoids at least a portion of the restriction on the robot arm's movement and expands the range of motion of the surgical instruments.

[0036] As described above, the pivot point is set at an opening formed in the patient's body, but since human tissue has a certain degree of flexibility, it is possible to shift the pivot point from its initial position to some extent. When viewed in a direction along the body surface, the pivot point can be moved, for example, within a radius of approximately 1 cm to several centimeters. In this embodiment, the direction in which the pivot point is shifted to avoid limitations on the movement of the robot arm may be along the body surface, but it is not necessarily limited to the direction along the body surface, and may also include cases where the pivot point is shifted in a direction that forms an angle with respect to the body surface.

[0037] When the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the direction and amount of movement when moving the pivot point setting position are determined based on the amount and direction of movement when the robot arm is controlled based on the input from the control device to move the tip of the surgical instrument (instrument tip). Here, the tip of the surgical instrument is, for example, the part of the pair of jaw members in the case of forceps, or the tip of the endoscope body (camera part) in the case of an endoscope.

[0038] Situations in which the movement of a robotic arm is restricted and the range of motion of surgical instruments is reduced are related, for example, to avoiding interference between a robotic arm being operated by an input and an adjacent robotic arm. For example, a robotic arm control device generates a first arm model by modeling at least a portion of the robotic arm, and generates a second arm model by modeling at least a portion of another robotic arm. Situations in which the movement of a robotic arm is restricted and the range of motion of surgical instruments is reduced can be related to the proximity distance between the first arm model and the second arm model becoming smaller than the minimum allowable distance. When the proximity distance between the first arm model and the second arm model becomes smaller than the minimum allowable distance, the configuration of the robotic arm being operated by the input is changed in a direction that increases the proximity distance between the arms by moving the pivot point setting position corresponding to the robotic arm being operated by the input. This point will be described in more detail later with reference to the drawings.

[0039] In robot arms, it is possible that the inverse kinematics calculations may not be able to find a solution (combination of joint angles and linear motion) that realizes the given position and orientation of the surgical instrument within the constraints of the robot arm and surgical instrument mechanisms. As a result of the inverse kinematics calculations failing to find a solution, the movement of the robot arm may be restricted, thereby reducing the range of motion of the surgical instrument. The success or failure of the inverse kinematics calculations can change depending on the shape of the robot arm, so by changing the pivot point setting, the shape of the robot arm may change, and in some cases the inverse kinematics calculations may be able to find a solution. By devising the logic for changing the pivot point setting, it may be possible to make the surgical instrument perform the desired movement while minimizing the change in the overall shape of the robot arm, and by utilizing this, the possibility of the inverse kinematics calculations finding a solution can be increased. This point will be explained in detail later with reference to the drawings.

[0040] The control device for the robot arm may be configured to move the pivot point from its initial setting position when the robot arm's movement is restricted and the range of motion of the surgical instrument is reduced, and then move the pivot point back towards the initial setting position when the robot arm's movement is not restricted. For example, when the robot arm's movement is not restricted, if the direction in which the robot arm is controlled based on the input to move the tip of the surgical instrument is the same as the direction in which the pivot point returns to its initial setting position, the pivot point may be moved back towards the initial setting position according to the amount of movement of the tip of the surgical instrument. In this way, it is possible to ensure as much as possible that the pivot point is at or close to the initial setting position, which may minimize changes in the operator's feel (occurrence of discomfort) when operating the control device. In addition, it may be possible to reduce the force applied to the opening by having the pivot point offset from the opening.

[0041] Alternatively, the control device for the robot arm may be configured such that, once the pivot point is moved from its initial setting position when the robot arm's movement is restricted and the range of motion of the surgical instrument is reduced, it does not move the pivot point back towards the initial setting position even when the robot arm's movement is not restricted. For example, even when the robot arm's movement is not restricted and the direction in which the robot arm is controlled based on the input to move the tip of the surgical instrument is in the direction of returning the pivot point to its initial setting position, the control device for the robot arm does not move the pivot point back towards the initial setting position. In this way, the frequency of moving the pivot point can be reduced compared to a control method that returns the pivot point to the initial setting position. This reduces the amount of computation (computational load) in the calculation processing for controlling the robot arm.

[0042] The robotic arm of the surgical robot in the surgical robot system according to this embodiment has redundancy. That is, the degrees of freedom required for the task to be accomplished by the robotic arm are smaller than the degrees of freedom possessed by the robotic arm (i.e., the number of drive axes). Conversely, the degrees of freedom of the robotic arm are larger than the degrees of freedom required for the task. The degrees of freedom required for the task to be accomplished by the robotic arm are typically the degrees of freedom required for controlling the position and orientation of a surgical instrument detachably attached to the tip of the robotic arm (this is the task). Here, the number of drive axes that determine the degrees of freedom of the robotic arm includes the number of drive axes for controlling the joints of the surgical instrument itself (the joints of the movable parts of the surgical instrument) attached to the tip of the robotic arm, and / or the number of drive axes for rotating the entire surgical instrument relative to the tip of the robotic arm.

[0043] When the robotic arms of a surgical robot that constitute the slave unit have redundancy, the solution (combination of multiple axis values) for determining each axis value of the robotic arm from the slave coordinates using inverse kinematics calculations is not uniquely determined, and there are infinitely many solutions. Therefore, it is not possible to determine each axis value of the robotic arm, and in this state, it is not possible to control the movement of the robotic arm.

[0044] When a robotic arm has redundancy, there are extra axes that do not necessarily need to be operated from the perspective of achieving the task. Such extra axes can be called redundant axes. Since the robotic arm as a whole has extra axes, a specific axis among the multiple axes that make up the robotic arm is not necessarily determined to be a redundant axis. In other words, in inverse kinematics calculations for a redundant robotic arm, which axis is treated as a redundant axis is not a given condition that is necessarily determined by the configuration of the robotic arm, but rather a matter that should be determined retrospectively.

[0045] In the control method for the surgical robot system according to this embodiment, one drive axis is assigned to each redundant degree of freedom in the robot arm, and the drive axis to which such a redundant degree of freedom is assigned is positioned as a 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 (drive axes) of the robot arm is n+3, then the robot arm will have three redundant degrees of freedom. In this case, three drive axes are selected from the n+3 drive axes of the robot arm as redundant axes, and each of the three selected drive axes is assigned to each of the three redundant degrees of freedom. The degrees of freedom required to control the position and orientation of a surgical instrument are, for example, the six degrees of freedom relating to the movement of the end effector provided at the tip of the shaft of the surgical instrument in three-dimensional space (for example, inside the patient's body).

[0046] Furthermore, if the shaft of a surgical instrument is inserted into a port member (trocar or cannula) provided on the patient's body surface, a pivot point may be set for the tilting motion of the shaft of the surgical instrument, which tilts together with the port member. In this case, it is necessary to control the movement of the surgical instrument so that the longitudinal axis of the shaft of the surgical instrument always passes through the pivot point or its vicinity. For this reason, the degrees of freedom n required to control the position and orientation of the surgical instrument increase by two, totaling eight.

[0047] In this specification, the shaft portion of a surgical instrument is a member or part that constitutes the whole or a part of the surgical instrument, and is an elongated portion or member having a longitudinal axis. The shaft portion of a surgical instrument may include those that include joints or that are flexible.

[0048] In the control method for the surgical robot system according to this embodiment, constraint conditions are added in proportion to the number of redundant degrees of freedom of the robot arm. The robot arm in this embodiment has multiple redundant degrees of freedom, and multiple constraint conditions are set accordingly. In this embodiment, the same number of drive axes as the number of redundant degrees of freedom are selected as redundant axes from among the multiple drive axes of the robot arm, and one constraint condition is set for each redundant axis. Note that the actual drive axes and redundant axes may be matched one-to-one, but the method is not necessarily limited to a one-to-one correspondence. For example, the relationship between the axis values ​​of two drive axes can also be treated as a redundant axis. Specifically, if the axis value of one drive axis is θ1 and the axis value of another drive axis is θ2, then θ defined by the constraint equation θ1 + θ2 = θ can be considered as the axis value of a new (virtual) redundant axis. The constraint conditions, for example, constrain the operation of the redundant axis corresponding to that constraint condition in relation to the configuration of the robot arm, which is determined by the combination of axis values ​​of the multiple drive axes of the robot arm. In other words, constraints are imposed on the shape of the robot arm, and the movement of the redundant axes corresponding to these constraints is controlled so that the changes in the shape of the robot arm remain within the range constrained by the constraints. This point will be explained in more detail later with reference to Figure 35, etc.

[0049] By setting multiple constraint conditions in the control of the robot arm in this manner, in this embodiment equipped with a robot arm having multiple redundant axes, a fixed solution can be calculated when calculating the axis value (joint variable value) of the robot arm's drive axis from the position and orientation of the end effector of the surgical instrument. That is, in this embodiment, once the position and orientation of the end effector of the surgical instrument are determined, the axis value (joint variable value) of the redundant axis is uniquely determined by the constraint conditions. For example, the constraint conditions can be composed of a mathematical formula for uniquely determining the axis value of the redundant axis based on the position and orientation of the end effector. Since the axis value of the redundant axis can be determined by the constraint conditions in this way, the same inverse kinematic calculation as in the case where there is no redundant axis can be applied to the multiple drive axes other than the redundant axis. The axis value of the redundant axis can also be called the joint position or joint angle.

[0050] The constraint conditions for redundant axes are related to which of the robot arm's multiple drive axes (multiple joints) are treated as redundant axes. In other words, the content of the constraint conditions for redundant axes can change depending on which of the robot arm's multiple drive axes are selected as redundant axes. Furthermore, the constraint conditions for redundant axes can be determined from the perspective of avoiding interference between arms. 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 expected to be unlikely.

[0051] As described above, constraint conditions for redundant axes can be determined from the perspective of avoiding interference between arms, but the content of the constraint conditions once determined is not always optimal. For example, in a certain surgery, even if the arm interference avoidance effect is properly achieved at one stage of the surgery, the arm interference avoidance effect that was initially planned may not be achieved at another stage of the surgery.

[0052] Therefore, in this embodiment, the constraint conditions for the redundant axis are not positioned as fixed conditions that remain unchanged once set, but rather as conditions that can be dynamically changed according to the situation at the time, for example, even during surgery. In other words, in this embodiment, the constraint conditions for the redundant axis, which are set at a point before the start of surgery (e.g., during setup), can be dynamically changed after the start of surgery, for example, during the following actions by the operator (surgeon), according to the situation at the time.

[0053] When the constraint conditions for redundant axes are changed, the axis values ​​of the robot arm's multiple drive axes (joints) change as a result. Specifically, the axis values ​​of the robot arm's multiple drive axes are determined by calculations based on the command values ​​for the position and orientation of the end effector, which are generated based on the operation input from the control device. This calculation process includes information related to the constraint conditions for redundant axes. Therefore, when the constraint conditions for redundant axes are changed, the content of the calculation process used to determine the axis values ​​of the robot arm's multiple drive axes (joints) 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 calculation process also change.

[0054] Here, the movement 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 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. When the axis values ​​of 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 the robot arm can be defined as the spatial region occupied by the robot arm in the absolute coordinate system (or 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 space region occupied by the robot arm due to a change in the constraints of the redundant axes can be achieved without affecting the motion of the end effector. In other words, by changing the constraints of the redundant axes, the space region occupied by the robot arm can be changed without affecting the motion of the end effector.

[0055] As described above, the shape of the robot arm can be changed and its occupied space altered without affecting the movement of the end effector. For example, if there is a possibility of the arms approaching and interfering with each other while an operator (practitioner) is performing a procedure by operating the control device (during the so-called following motion), the control device can dynamically change the constraint conditions of the redundant axes to avoid interference between the arms in advance, without interrupting the operator's procedure (i.e., without interrupting the following motion).

[0056] If interference between the arms occurs and the surgical robot stops, it may be necessary to release the stopped (locked) state of the surgical robot while considering the patient's safety. For example, it may be necessary to temporarily remove the surgical instrument from the port member, change the robot arm to the appropriate shape, reattach the surgical instrument to the robot arm, and then release the stopped state of the surgical robot. In this way, when a surgical robot stops due to interference between the arms, it takes time and effort to release it, and the surgery is interrupted during that time. In contrast, according to this embodiment, interference between the arms can be avoided in advance, so it is possible to reliably prevent the surgery from being interrupted by the stopping of the surgical robot and the subsequent recovery work. Thus, according to this embodiment, the continuity of the surgery by the operator can be reliably guaranteed in surgery using a surgical robot system.

[0057] As described above, the surgical robot system and its control method according to this embodiment include a function to dynamically change the pivot point setting position (automatic pivot position adjustment function) and a function to dynamically change the constraint conditions of redundant axes (automatic constraint condition adjustment function). In controlling the robot arm, the automatic pivot position adjustment function can be applied independently, or the automatic constraint condition adjustment function can be applied independently. The automatic pivot position adjustment function can be applied regardless of whether the robot arm has redundancy or not. In other words, the automatic pivot position adjustment function does not necessarily require the robot arm to have redundancy.

[0058] Based on the judgment that the pivot point should not be moved as much as possible during surgery (especially during following movements), the automatic constraint adjustment function may be applied preferentially over the automatic pivot position adjustment function. In other words, if the range of motion of surgical instruments is limited due to interference between robot arms, the automatic constraint adjustment function will be used first to try to avoid the limitation of the range of motion of the surgical instruments. If the limitation of the range of motion of the surgical instruments can be avoided in this way, the automatic pivot position adjustment function will not be applied. On the other hand, if the automatic constraint adjustment function cannot avoid the limitation of the range of motion of the surgical instruments at all, or cannot avoid it completely, the automatic pivot position adjustment function will be applied instead of the automatic constraint adjustment function, or in addition to the automatic constraint adjustment function, to avoid the limitation of the range of motion of the surgical instruments.

[0059] The surgical robot system and its control method according to this embodiment will be described below with reference to the drawings. First, the overall configuration of the surgical robot system will be described, followed by the automatic pivot position adjustment function, and then the automatic constraint condition adjustment function.

[0060] As shown in Figures 1 to 3, the surgical robot system 10 according to this embodiment comprises a surgical robot 1 which constitutes at least a part of the slave unit, and an operating device 2 which constitutes at least a part of the master unit. The operating device 2 is located next to the operating table 111 in the operating room. The operating device 2 may be located at a further distance from the operating table 111 in the operating room, or it may be located outside the operating room. The operator (surgeon) S who performs surgery using the surgical robot system 10 is located on the side of the operating device 2 rather than the surgical robot 1 side during the procedure in order to operate the operating device 2. The patient P on whom the surgery is performed is placed on the operating table 111 which is located next to the surgical robot 1.

[0061] Operator S inputs control signals to the operating device 2 to control the position and orientation of the surgical instrument 40. The control signals input to the operating device 2 are transmitted via wired or wireless connection to the arm control unit 28 of the surgical robot 1. The arm control unit 28 generates motion commands for the surgical robot 1 based on the control signals input to the operating device 2. The surgical robot 1 is operated based on these motion commands. In this way, the operating device 2 constitutes an interface between the surgical robot system 10 and operator S, and is a device (master unit) for remotely operating the surgical robot 1 (slave unit).

[0062] The operating device 2 includes left and right operating manipulators 20A and 20B, a plurality of operating 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 located on a support bar 26. The operating manipulators 20A and 20B are equipped with left and right hand controls 21A and 21B for the operator to input operating commands using their left and right hands. The operating manipulators 20A and 20B are operating devices that receive input for generating motion commands for the position and posture of surgical instruments 40. The operating pedals 22 are operating devices that receive commands such as zooming the endoscope camera, switching control modes, and switching between robot arms 3 (3A, 3B, 3C, 3D) associated with the left and right operating manipulators 20A and 20B.

[0063] The monitor 24 is a scope-type display device that displays images taken by an endoscope inserted into the patient P's body. 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 at the same height as the operator S's face. A sensor 27 for detecting the operator S's head is provided near the monitor 24. For example, the arm control unit 28 is configured such that remote control of the surgical robot 1 by the operating device 2 is possible only if the operator S's head is detected by the sensor 27, and remote control of the surgical robot 1 by the operating device 2 is not possible if the operator S's head is not detected by the sensor 27. The operator S operates the hand controls 21A, 21B and the operating pedal 22 of the operating manipulators 20A, 20B while viewing the affected area of ​​patient P on the monitor 24.

[0064] The surgical robot 1 constitutes the interface between the surgical robot system 10 and the patient P. The surgical robot 1 is positioned in the operating room next to the operating table 111 on which the patient P lies. The operating table 111 and its surroundings in the operating room are sterilized to form a sterile field.

[0065] The surgical robot 1 comprises 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.

[0066] As shown in Figure 4, in this embodiment, four robot arms 3A, 3B, 3C, and 3D are attached to the arm base 5. The number of robot arms 3 may be less than four or more than four. Each of the multiple robot arms 3's tip 32 (see Figure 8) includes an instrument holder 36 to which surgical instruments 40 are detachably attached (see also Figure 9). In other words, the instrument holder 36 constitutes at least a part of the tip 32 of the robot arm 3.

[0067] The positioner 7 is composed of, for example, a 7-axis vertical articulated robot. The positioner 7 includes a base 90 and a series of link parts 91 whose base ends are connected to the base 90. The multiple links 91 are connected to each other by joint parts 92. The base 90 of the positioner 7 is mounted on the upper surface of the 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 in three dimensions. That is, the positioner 7 can move the position of the arm base 5 in three dimensions along mutually orthogonal X, Y, and Z axis directions relative to the movable carriage 70, and can rotate the orientation of the arm base 5 around the roll axis, pitch axis, and yaw axis.

[0068] The arm base 5 comprises an arm base body 50, a positioner mounting portion 51 provided on the back of the arm base body 50 to which the tip of the positioner 7 is attached, and a plurality of arm mounting portions 52 provided on the lower part of the arm base body 50 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 of the positioner 7. The arm base 5 is provided with an imaging unit 53. The imaging unit 53 can photograph at least one of the operating table 111 and the patient P placed on the operating table 111.

[0069] The positioner 7, arm base 5, and the components 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 components are shielded from the sterile field in the operating room.

[0070] Figure 5 shows a forceps assembly 40A as an example of a surgical instrument 40. The forceps assembly 40A comprises a shaft portion 43, an end effector 44 including a pair of jaws provided at its tip, and an instrument base 45 that rotatably holds the base end of the shaft portion 43 around the longitudinal axis of the shaft portion 43.

[0071] Figure 6 shows another example of a surgical instrument 40, an endoscopic assembly 40B, which is an imaging device inserted into a patient's body to image the surgical site. The endoscopic assembly 40B includes an endoscope 12 and an endoscope holder 13. The endoscope holder 13 holds the endoscope 12 so that it can rotate around its longitudinal axis. Inside the endoscope holder 13 is a drive unit (not shown) for rotating the endoscope 12 around its longitudinal axis. The front portion (camera side) of the endoscope 12 is formed as a shaft portion 43.

[0072] As described above, the shaft portion 43 of the surgical instrument 40 may refer to an elongated member with an end effector 44 attached to its tip, or it may refer to the front portion (camera side portion) of the endoscope 12, which is formed as an elongated member.

[0073] The instrument base 45 of the forceps assembly 40A is provided with a locking portion (not shown) that can be releasably locked to the instrument holder 36 of the robot arm 3, and the instrument holder 36 is provided with a receiving portion (not shown) into which the locking portion is locked. For example, the locking portion and the receiving portion have complementary shapes, and a retractable portion that extends and retracts elastically on one of the locking portion and the receiving portion is releasably locked to a recess on the other of the locking portion and the receiving portion. For example, a surgical assistant can manually release the retractable portion that is elastically locked to the recess and remove the forceps assembly 40A from the instrument holder 36. The endoscope holder 13 also has the same attachment and detachment mechanism as described above and can be attached to and detached from the instrument holder 36 by manual operation by a surgical assistant.

[0074] 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 robot arms 3 (four in this example). Other surgical instruments, such as forceps assemblies 40A, are detachably held as surgical instruments 40 in the instrument holders 36 of the remaining robot arms 3 (three in this example). In the surgical robot 1 shown in Figure 4, the endoscope assembly 40B is attached to the second robot arm 3B, and other surgical instruments, such as forceps assemblies 40A, are attached to the first, third, and fourth robot arms 3A, 3C, and 3D, respectively.

[0075] In the surgical robot 1, the arm base 5 functions as a "hub" that serves as the base for multiple robot arms 3. In this embodiment, the positioner 7 is composed of a vertical articulated robot, but the positioner 7 can also be composed of a manipulator other than a vertical articulated robot. For example, the positioner 7 may be a linear rail for supporting the arm base 5, a lifting device, or a bracket attached to the ceiling or wall. In this embodiment, the base 90 of the positioner 7 is attached to a movable trolley 70, but instead, the base of the positioner 7 can be attached to a fixed object such as the wall, floor, or a member fixed to these in the operating room.

[0076] Furthermore, the trolley 70 is equipped with an operation unit 72 for setting and inputting the position and orientation (preparation posture) of the positioner 7, arm base 5, and multiple robot arms 3, mainly before the procedure. The operation unit 72 includes, for example, a touch panel.

[0077] In the surgical robot 1 described above, multiple components are connected in a series, from the positioner 7 to the surgical instrument 40. In this specification, the end of the 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 end on the opposite side may be referred to as the "tip (of the series of components)."

[0078] The arm control unit 28, which controls the operation of the surgical robot 1 based on operation input from the operating device 2, may consist of a single controller that centrally controls the robot, or it may consist of multiple controllers that cooperate with each other to perform distributed control. As shown in Figure 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, memory 302 such as ROM and RAM, an I / O unit (input / output unit) 303, and an interface 304. The memory 302 stores control programs and various data used for controlling the operation of the surgical robot 1. The interface 304 is used for communication with the operating device 2, various sensors (such as encoders that detect the rotation angle of servo motors, which will be described later), etc.

[0079] Figure 8 shows a schematic configuration of one of the multiple robot arms 3 provided by the surgical robot 1. A surgical instrument 40 is detachably attached to the tip 32 of the robot arm 3. In this embodiment, all of the multiple robot arms 3 provided by the surgical robot 1 have the same or similar configuration, but at least one of the multiple robot arms 3 may have a different configuration from the other robot arms 3 (for example, having different degrees of freedom). As shown in Figure 8, the robot arm 3 comprises an arm body 30 and a translational movement mechanism 35 provided on the arm body 30. The translational movement mechanism 35 has an instrument holder 36 that is movably provided on its main body. The translational movement mechanism 35 (including the instrument holder 36) constitutes at least a part of the tip 32 of the robot arm 3. As shown in Figures 8 and 9, the instrument base 45 of the surgical instrument 40 is detachably attached to the instrument holder 36 by a detachable mechanism (not shown). The tip portion 32 of the robot arm 3 is movable in three dimensions relative to the base portion 80 of the robot arm 3.

[0080] As shown in Figures 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 includes a command input unit 39A, which includes buttons, 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. Commands input from the command input unit 39A include, for example, commands relating to a retraction operation that retracts the surgical instrument 40 inserted into the port member 112 to a retracted position. A surgical assistant standing next to the surgical robot 1 may operate the command input unit 39A to control the retraction operation of the surgical instrument 40 by the manual controller 39B.

[0081] The arm body 30 comprises a base end 80 that is detachably attached to the arm base 5, and a plurality of arm link sections sequentially connected from the base end 80 toward the tip. The arm body 30 is configured with a plurality of joint sections (a plurality of drive shafts) by sequentially connecting one arm link section so that it rotates relative to another arm link section. The plurality of arm link sections include the first link 81 to the sixth link 86. The plurality of joint sections include the first joint J31 to the seventh joint J37. In this embodiment, the plurality of joint sections (first joint J31 to the seventh joint J37) of the arm body 30 are configured as rotary joints equipped with a rotation axis, but at least some of the joint sections may be configured as linear joints.

[0082] More specifically, the base end of the first link 81 is connected to the tip end of the base end 80 of the robot arm 3 via a torsional (roll) joint, the first joint J31 (base-side torsional joint). The base end of the second link 82 is connected to the tip end of the first link 81 via a bending (pitch) joint, the second joint J32. The base end of the third link 83 is connected to the tip end of the second link 82 via a torsional joint, the third joint J33. The base end of the fourth link 84 is connected to the tip end of the third link 83 via a bending joint, the fourth joint J34. The base end of the fifth link 85 is connected to the tip end of the fourth link 84 via a torsional joint, the fifth joint J35. The base end of the sixth link 86 is connected to the tip end of the fifth link 85 via a bending joint, the sixth joint J36. The base end of the translational movement mechanism 35 is connected to the tip of the sixth link 86 via the seventh joint J37 (tip-side bending joint), which is a bending joint.

[0083] In this embodiment, the first link 81 has a bent shape between adjacent joints J31 and J32. In other words, the first link 81 is configured so that the axis of rotation of the first joint J31 and the axis of rotation 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 proximal end of the first joint J31 in a predetermined first direction (the direction of the axis of rotation of the first joint J31). The second portion 81b extends from the tip of the first portion 81a in a second direction intersecting the extension direction of the first portion 81a (and perpendicular to the axis of rotation of the second joint J32) and connects to the tip of the second joint J32. The angle between the first direction and the second direction in the first link 81 is, for example, 120 degrees or more and 160 degrees or less (for example, 140 degrees). Furthermore, the first part 81a and the second part 81b are smoothly connected. This makes it easier to pass wires such as electrical wiring through multiple arm link sections, even if some of the arm link sections have a bent shape.

[0084] Furthermore, the fourth link 84 has a bent shape between adjacent joints J34 and J35, and this portion is the elbow 11 of the arm body 30. In other words, the fourth link 84 is configured so that the axis of rotation of the fourth joint J34 and the axis of rotation of the fifth joint J35 do not intersect. The axis of rotation of the fifth joint J35 is offset from the axis of rotation of the fourth joint J34 in a direction perpendicular to the axis of rotation of the fourth joint J34 and the axis of rotation of 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 proximal end of the fourth joint J34 in a predetermined first direction (a direction perpendicular to both the axis of rotation of the fourth joint J34 and the axis of rotation of the fifth joint J35). Furthermore, the second portion 84b extends from the tip of the first portion 84a in a second direction (the rotation axis direction of the fifth joint J35) that intersects the extension direction of the first portion 84a, and connects to the fifth joint J35 on the tip side. The angle between the first direction and the second direction in 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.

[0085] 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.

[0086] Each arm link portion is configured such that the area of ​​the cross-section perpendicular to the longitudinal direction is smaller than that of the arm link portion (or base portion 80) connected to the base end portion of that arm link portion. As a result, the arm body 30 is configured to gradually become thinner from the base portion 80 toward the tip end. Furthermore, each joint J32, J34, J36, which is a bending joint, is configured such that the tips of the arm link portions 81, 83, 85 on the base end side are located on one side of the rotation axis with respect to the center of the rotation axis in the joint portion. In addition, the base ends of the arm link portions 82, 84, 86 on the tip end side are configured to face the tips of the arm link portions 81, 83, 85 on the base end side on the other side of the rotation axis with respect to the center of the rotation axis in the joint portion.

[0087] Furthermore, the width in the rotational axis direction at the joint, that is, the distance between the rotational axis direction outer end of the tip of the arm link portion 81, 83, 85 on the base end side and the rotational axis direction outer end of the base end of the arm link portion 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 portion of the arm link portion 81, 83, 85 located on the base end side from the tip.

[0088] In this way, each joint and the arm link portion at its tip are configured to be narrower than the arm link portion at its base. This makes it possible to increase the range of motion of each arm body 30 (the range in which it does not interfere with other arm bodies 30) in a workspace that narrows as it approaches the treatment area 110 of the patient P.

[0089] The outer shell of the arm body 30 is formed from a material that has chemical resistance due to painting. In addition, openings such as inspection holes in the arm body 30 are covered with resin covers. By forming these covers from a material such as resin, the weight of parts that do not contribute to the strength of the arm body 30 can be reduced. As a result, even if the cover falls off or the arm body 30 hits another arm body 30 or a treatment assistant, the impact can be reduced. Note that the outer shell of the arm body 30 itself may include parts made of resin material.

[0090] The translational movement mechanism 35 is a mechanism that allows the surgical instrument 40 mounted on the instrument holder 36 to be translated in the direction of extension of the shaft portion 43 by translating the instrument holder 36, which is movably provided on the main body of the translational movement mechanism 35, in the direction of the long axis Dt (Figure 8).

[0091] The translational movement mechanism 35 is connected to the tip of the sixth link 86 of the arm body 30 via a bending joint, the seventh joint J37. The seventh joint J37 extends in a direction perpendicular to the long axis direction Dt. Inside the translational movement mechanism 35 is a drive mechanism including a drive source for translating the instrument holder 36. The translational movement mechanism 35 can advance the surgical instrument 40 in the insertion direction and retract it in the withdrawal direction. The drive mechanism provided inside the translational movement mechanism 35 may be configured using, for example, a pulley and timing belt, or a mechanism including a gear train, or it may be configured as a double-speed mechanism. In this way, the translational movement mechanism 35 constitutes the eighth joint J38, which is a linear joint that moves the instrument holder 36 in a straight line in the long axis direction Dt.

[0092] The instrument holder 36 detachably holds the instrument base 45 of the surgical instrument 40. As shown in Figure 10, the instrument holder 36 includes an instrument drive unit 38 having a plurality (four in this example) of drive shafts 37 that rotate to provide driving force to the surgical instrument 40. One of the plurality of drive shafts 37 of the instrument drive unit 38 generates a driving force that rotates the shaft portion 43 of the surgical instrument 40 around its longitudinal axis.

[0093] As shown in Figure 5, the forceps assembly 40A, 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 instrument) 44 connected to the tip of the shaft portion 43. Furthermore, the forceps assembly 40A is equipped with a drive force transmission unit (not shown) that transmits the driving force of the drive shaft 37, which is connected to the drive shaft 37 of the instrument drive unit 38 included in the instrument holder 36 when the forceps assembly 40A is mounted in the instrument holder 36. The instrument drive unit 38 of the instrument holder 36 has, for example, four drive shafts 37, and these drive shafts 37 are used, for example, for opening and closing the pair of jaws that are the end effector 44 of the forceps assembly 40A (Figure 5), pitching or yawing the end effector 44, and rolling the shaft portion 43 of the forceps assembly 40A around its longitudinal axis relative to the instrument base 45.

[0094] 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 43.

[0095] The surgical instrument 40 has a defined longitudinal axis Dt (see Figure 8), and the instrument base 45, shaft portion 43, and end effector 44 are arranged in this order along the longitudinal axis Dt. The end effector of the surgical instrument 40 is not limited to the end effector 44 consisting of a pair of jaws as shown in Figure 5. That is, the end effector of the surgical instrument 40 can be selected from a group that includes, for example, instruments with movable joints (e.g., forceps, scissors, grippers, needle holders, microdisectors, staple applicators, tackers, suction and cleaning tools, snare wires, and clip applicators, etc.) and instruments without joints (e.g., cutting blades, cauterization probes, washers, catheters, and suction orifices, etc.).

[0096] The base end of the shaft portion 43 is connected to the instrument base 45 via a ninth joint J39 (tip-side torsional joint), which is a torsional (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 portion 43. The central axis C of the shaft portion 43 corresponds to the longitudinal axis of the surgical instrument 40. Note that the rotation axis of a joint refers to the geometric (imaginary) axis of the rotating shaft. Furthermore, as described above, in this embodiment, the instrument base 45 and the ninth joint J39 may also be elements included in the robot arm 3 for positioning the shaft portion 43.

[0097] As mentioned above, the eighth joint J38, located between the seventh joint J37 and the ninth joint J39, is a linear joint, so 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 the reference plane RP (Figure 8), which includes the rotation axis R9 of the ninth joint J39 and extends in the direction of the long axis Dt. In other words, in this embodiment, the seventh joint J37 constitutes a bending joint that defines the reference plane RP. Note that the angle between the rotation axis R7 and the reference plane RP is not limited to a right angle; the rotation axis R7 and the reference plane RP only need to intersect. By rotating the seventh joint J37, the shaft portion 43 can be swung in the direction of tilting up and down.

[0098] As shown in Figure 11, in this embodiment, multiple (four in this example) arm mounting sections 52 are provided on the arm base 5 to correspond to multiple (four in this example) robot arms 3. The arm base 5 has an elongated shape with a longitudinal axis, and the multiple arm mounting sections 52 are arranged in the longitudinal direction of the arm base 5 (the direction indicated by D1 in Figure 11). By fixing the base ends 80 of the multiple robot arms 3 to the multiple arm mounting sections 52, the first link 81, which is the link on the base end 80 side of the multiple robot arms 3, is configured to be rotatable relative to the rotation axis of the first joint J31.

[0099] Specifically, the multiple arm mounting sections 52 are arranged in a line in a predetermined first direction D1, with the base ends 80 of multiple robot arms 3 aligned in a predetermined first direction D1. The first direction D1 is a direction set (included) on a predetermined first plane P1. In this embodiment, the first plane P1 is a virtual plane parallel to the floor surface (horizontal plane) G when the arm base 5 is in the preparation position (see Figure 3), and the first direction D1 is, for example, the direction of the longitudinal axis of a long arm base 5 and is horizontal, but is not limited to this. Also, the first direction D1 is perpendicular to the rotation axis R1 of the first joint J31 of the robot arm 3, which will be described later. That is, when viewed from above with the arm base 5 in the preparation position, the multiple arm mounting sections 52 are arranged in a line in the first direction D1 (the depth direction of the paper in Figure 3) and face a second direction D2 that is perpendicular to the first direction D1. The arrangement of the arm mounting sections 52 is not limited to a single line, but may be arranged in two lines. Furthermore, some of the arm mounting portions 52 may be offset in the second direction D2. Also, some of the arm mounting 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 plane of the paper in Figure 11).

[0100] In the above description, 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. However, these instrument base 45 and the ninth joint J39 can also be considered components included in the robot arm 3.

[0101] Figure 12 is a schematic block diagram showing an example of the configuration of the control system of the surgical robot system 10. The arm body 30 of the robot arm 3 is provided with servo motors (indicated as SM in Figure 12) M31 to M37 for driving, encoders (indicated as EN in Figure 12) E31 to E37 for detecting the rotation angle of the servo motors M31 to M37, and a reduction gear (not shown) that reduces the output of the servo motors M31 to M37 to increase torque, corresponding to each joint J31 to J37 of the arm body 30.

[0102] In Figure 12, the first joint J31 and the seventh joint J37 of the arm body 30 are shown as representative examples of the joints J31 to J37, and the control systems for the other joints J32 to J36 are omitted. Furthermore, the translational movement mechanism 35 is provided with a servo motor M38 for the translational movement of the eighth joint J38 (a servo motor that drives the interlocking mechanism), a servo motor M39 for the rotational movement of the ninth joint J39, encoders E38 and E39 for detecting the rotation angles of the servo motors M38 and M39, and a reduction gear (not shown) that reduces the output of the servo motors M38 and M39 to increase torque.

[0103] Encoders E31 to E39 are provided as an example of rotational position detection means for detecting the rotational position (rotation angle) of servo motors M31 to M39, and other rotational position detection means such as resolvers may be used instead of encoders E31 to E39.

[0104] The arm control unit 28 includes a control unit body 29 that controls the movement of multiple robot arms 3 based on motion commands. The control unit body 29 is electrically connected to servo control units C31 to C39, indicated as SC in the figure, and multiple actuators related to servo motors M31 to M39 are electrically connected via amplification circuits and the like.

[0105] In the above configuration, a position and orientation command for the tip of the robot arm 3 is input to the control unit 29 based on the operation input received by the operating device 2 during the procedure. The control unit 29 generates and outputs a position command value based on the position and orientation command and the rotation angle detected by encoders E31 to E39. The servo control units C31 to C39, having acquired this position command value, generate and output a drive command value (torque command value) based on the rotation angle detected by encoders E31 to E39 and the position command value. The amplification circuit, having 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 of the robot arm 32 reaches the position and orientation corresponding to the position and orientation command.

[0106] Furthermore, the arm control unit 28 is equipped with a storage unit 31 that can read data from the control unit body 29, and surgical information input via the operating device 2 is stored in advance. This surgical information includes combinations of multiple robot arms 3 used in surgery.

[0107] Furthermore, the memory unit 31 stores information such as the length of the surgical instrument 40 held at the tip 32 of the robot arm 3 along its long axis Dt. As a result, the control unit 29 can determine 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 of 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).

[0108] Furthermore, the memory unit 31 stores in advance predetermined preparation positions established before the procedure of the arm base 5 and the multiple robot arms 3 (for example, the positions and orientations of the positioner 7, arm base 5, and robot arms 3 shown in Figure 3). Multiple preparation positions may be stored in the memory unit 31 depending on the content (type) of the procedure, the area to be treated, etc. The above-mentioned predetermined preparation positions are sometimes called setup positions.

[0109] As shown in Figures 1 to 3, in surgery using the surgical robot 1, first, the surgical assistant (or the operator S himself) moves the surgical robot 1 close to the operating table 111 using the trolley 70. At this time, the positioner 7, arm base 5, and multiple robot arms 3 are positioned in predetermined storage positions set on the trolley 70.

[0110] On the body surface of patient P lying on the operating table 111, port members 112, consisting of trocars and cannulas, are positioned, for example, in a straight line side by side. In Figure 3, the port members 112 are arranged in a single line in the depth direction of the paper. However, the arrangement of multiple port members 112 is not limited to this arrangement.

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

[0112] The assistant then sets a remote center RC (a predetermined center point) associated with each robot arm 3 in a one-to-one correspondence to the arm control unit 28. In this operation, the assistant attaches a teaching surgical instrument 40 to the instrument holder 36, for example, and moves the teaching surgical instrument 40 so that its tip is positioned in the center of the hole in the port member 112. The assistant then inputs an instruction to set the remote center RC into the operation unit 72. Based on this, the arm control unit 28 performs a forward conversion and calculates the position of the remote center RC 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 portion 80, and information relating to the parameters of each arm link portion.

[0113] The remote center RC functions as the pivot point described above. That is, in the following mode, when the arm control unit 28 controls the robot arm 3 to operate the surgical instrument 40 in response to the operation input from the operating device 2, it controls the robot arm 3 so that the central axis C (longitudinal axis) of the shaft portion 43 of the surgical instrument 40 passes through the remote center (pivot point) RC. The remote center (pivot point) RC is set at an opening formed in the patient's body (especially the body surface such as the abdominal wall).

[0114] In the first direction D1, the remote center RC associated with each robot arm 3 is arranged in the order of the robot arms 3, and the port member 112 are associated in a one-to-one correspondence. That is, the first robot arm 3A from the right in the first direction D1 is associated with the first port member 112 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 first remote center RC from the right in the first direction D1. The same applies to the other robot arms 3B, 3C, and 3D.

[0115] Then, the assistant or operator S replaces the teaching surgical instrument 40 with another surgical instrument 40, such as a forceps assembly 40A or an endoscope assembly 40B. By performing these preliminary actions, the positioner 7, 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 will be the treatment site 110, and the surgical instruments 40 attached to each robot arm 3 are in a predetermined initial positional relationship.

[0116] In this initial position, the robot arm 3 has its base end 80 extending generally horizontally. The second link 82 and third link 83, which are connected to the bent first link 81, extend diagonally downward. More specifically, the second link 82 and third link 83 extend downward in the direction from the base end to the tip end of the base end 80 (towards the feet of the patient P on the operating table 111) within the direction in which the rotation axis R1 of the first joint J31 extends (second direction D2). The fourth link 84, fifth link 85 and sixth link 86 bend back with the elbow 11 as the apex and extend diagonally downward. More specifically, the fourth link 84, fifth link 85 and sixth link 86 extend downward in the direction from the tip end to the base end of the base end 80 (towards the head of the patient P on the operating table 111) within the direction in which the rotation axis R1 of the first joint J31 extends.

[0117] In this embodiment, the arm control unit 28 does not accept input from the operating device 2 while the surgical robot 1 (positioner 7, arm base 5, and multiple robot arms 3) is moving from the storage position to the preparation position. After the surgical robot 1 is in the preparation position, the arm control unit 28 becomes capable of accepting input from the operating device 2. During a procedure after the surgical robot 1 is in the preparation position, the arm control unit 28, in principle with the positioner 7 and arm base 5 stationary, generates operation commands based on the operation input generated by the operator S operating the operating device 2. The arm control unit 28 then controls the operation of each robot arm 3 in accordance with the operation commands generated based on the operation input from the operating device 2 to appropriately change the position and orientation of the surgical instrument 40. At this time, the arm control unit 28 controls the robot arms 3 by restricting the orientation of the surgical instrument 40 so that the shaft portion 43 of the surgical instrument 40 inserted through the port member 112 passes through the remote center RC. This restricts the movement of the port member 112 in the in-plane direction of the patient P's body surface.

[0118] Next, with reference to Figures 13 to 21, the automatic pivot position adjustment function described above will be explained in more detail.

[0119] As described above, in the surgical robot system and its control method according to this embodiment, the arm control unit 28, which is a control device for the robot arm, has a function to dynamically move the pivot point (remote center RC) set at the start of the surgery during the surgery (especially during the following motion), that is, an automatic pivot position adjustment function. More specifically, when the movement of the robot arm is restricted due to interference between the robot arm being operated and surrounding objects (for example, an adjacent robot arm), thereby reducing the range of motion of the surgical instrument, the arm control unit 28 moves the pivot point setting position in a direction that avoids the restriction on the movement of the robot arm and expands the range of motion of the surgical instrument.

[0120] Here, interference between the operating robot arm and surrounding objects is not limited to actual collisions between the operating robot arm and surrounding objects (e.g., adjacent robot arms), but also includes situations where, even if no actual collision occurs, the proximity of the operating robot arm model to the adjacent robot arm model becomes smaller than the minimum allowable value, and restrictions are placed on the operating robot arm's movement to prevent an actual collision. This point will be explained in more detail later with reference to the drawings.

[0121] Figure 13 is a diagram illustrating the control method when the pivot position is moved by the automatic pivot position adjustment function. In the state shown in the left side of Figure 13, the tip of the second robot arm 3B and the tip of the third robot arm 3C are close together. Therefore, when the tip of the surgical instrument 40 of the third robot arm 3C (end effector EE) is moved to the right in the diagram based on the operation input from the operating device 2, the rear end of the translational movement mechanism (linear axis) of the third robot arm 3C tilts to the left in the diagram and interferes with the translational movement mechanism (linear axis) of the second robot arm 3B.

[0122] Therefore, in this embodiment, the automatic pivot position adjustment function described above is used to avoid interference between the second robot arm 3B and the third robot arm 3C, thereby preventing the operating range of the tip (end effector EE) of the surgical instrument 40 attached to the third robot arm 3C from being restricted.

[0123] Specifically, if the amount of movement of the tip of the surgical instrument 40 (end effector EE) by controlling the third robot arm 3C based on the operation input is X, the amount of movement (shift) of the pivot point RC setting position in the direction in which the operating range of the end effector EE is expanded is Y, the distance from the reference point set on the opposite side of the end effector EE on the longitudinal axis of the surgical instrument 40 to the pivot point RC is A, and the distance from the pivot point RC to the end effector EE is B, then the pivot point RC setting position is moved so that the following equation Y = X × A / (A + B) is satisfied.

[0124] In this example, the position of the rear end of the translational movement mechanism (linear axis) is projected onto the longitudinal axis of the surgical instrument 40 (the central axis C of the shaft 43 of the surgical instrument 40) and used as the reference point (one of the starting points of distance A). The position of the end effector EE, which is the tip of the surgical instrument 40, corresponds to, for example, the tool center point (TCP). If the surgical instrument 40 is a forceps, the tool center point (TCP) corresponds to, for example, the pivot axis of a pair of jaws.

[0125] As shown in Figure 13, by moving the pivot point RC from its current position, the end effector EE can be moved without moving the rear end of the translational movement mechanism (linear axis) of the third robot arm 3C. This prevents the rear end of the translational movement mechanism (linear axis) of the third robot arm 3C from interfering with the second robot arm 3B (especially its translational movement mechanism). Therefore, the operation of the end effector EE of the surgical instrument 40 attached to the third robot arm 3C is not restricted, and the end effector EE can be moved to the target position.

[0126] Figure 14 is a schematic diagram illustrating a modified method for calculating the amount of pivot position movement (shift) in the automatic pivot position adjustment function. As shown in Figure 14(A), when moving the tip of the surgical instrument 40 (end effector EE) to the right in the figure by an amount X, in the example shown in Figure 13 above, as shown in Figure 14(B), the rear end of the translational movement mechanism (linear axis) was used as the reference point (star), and the distance from the reference point to the pivot point RC was defined as A.

[0127] In contrast, as shown in Figure 14(C), the reference point (star) can be set to a position closer to the pivot point RC than to the rear end of the translational movement mechanism (linear axis). In Figure 14(C), the position of the reference point can be, for example, the position of the seventh joint J37 (tip-side drive axis) projected onto the longitudinal axis C of the surgical instrument 40. By setting the position of the reference point to a position closer to the pivot point RC rather than the rear end of the translational movement mechanism (linear axis), the rear end of the translational movement mechanism (linear axis) will move to the left in the figure to some extent as the end effector EE moves to the right in the figure, but at the same time, the amount of change in the overall configuration of the robot arm can be suppressed to some extent. Therefore, if the end effector EE is moved without applying the automatic pivot position adjustment function (case shown in Figure 14(A)), even if the calculation process for inverse kinematics fails to find a solution and the end effector EE cannot be moved to the target position, the amount of change in the overall shape of the robot arm is suppressed, which may allow the calculation process for inverse kinematics to continue and find a solution. Alternatively, by suppressing the amount of change in the overall shape of the robot arm to some extent, interference between the arm portion located on the arm base side of the translational movement mechanism (linear axis) and other objects (for example, other robot arms) can be avoided, potentially expanding the operating range of the end effector EE.

[0128] Next, Figures 15(A), (B), and (C) correspond to Figures 14(A), (B), and (C), respectively. Figure 15 shows a case where the insertion depth of the surgical instrument 40 into the human body is greater than that shown in Figure 14. That is, the distance B from the end effector EE of the surgical instrument 40 to the pivot point RC is longer in the case shown in Figure 15 than in the case shown in Figure 14. Also, the distance A from the reference point (star) to the pivot point is shorter in the case shown in Figure 15 than in the case shown in Figure 14. In this example, the total distance of distance A and distance B remains the same in both the case shown in Figure 14 and the case shown in Figure 15. That is, the total distance of distance A and distance B in Figure 14(B) is the same as the total distance of distance A and distance B in Figure 15(B). Also, the total distance of distance A and distance B in Figure 14(C) is the same as the total distance of distance A and distance B in Figure 15(C).

[0129] The greater the insertion depth of the surgical instrument 40 into the patient's body, the greater the effect of expanding the range of motion of the end effector in relation to the amount of pivot point displacement.

[0130] Next, the control procedure for implementing the automatic pivot position adjustment function will be described with reference to Figures 16 to 18. Figure 16 is a flowchart showing the control procedure for the automatic pivot position adjustment function, Figure 17 is a schematic diagram illustrating the control procedure for the automatic pivot position adjustment function, and Figure 18 shows the meaning of the symbols shown in Figure 17.

[0131] In Figure 17, P ０ is the initial position (set value) of the pivot point on the XYZ coordinate system, P ｐ is the current position of the pivot point on the XYZ coordinate system (input), P ｎ is the target position (output) of the pivot point on the XYZ coordinate system, and T ｐ is the current position (input) of the end effector EE on the XYZ coordinate system, and T ｎ This is the target position (input) of the end effector EE on the XYZ coordinate system. Ｐ This is the allowable amount of displacement (set value) from the initial position of the pivot point, and in the verification described later, it was set to 20 mm. Note that the allowable amount of displacement LＰ may be determined in consideration of surgical procedures, the patient's physique, etc. L Ｔ is the distance (set value) from the end effector EE to the rear end of the translational drive mechanism (linear axis), and was set to 700 mm in the verification described later. Note that L Ｔ corresponds to the total distance of the distances A and B in FIG. 13 described above. Also, V Ｔ is the displacement vector (intermediate variable) of the end effector EE, and V Ｐ is the displacement vector (intermediate variable) of the pivot point.

[0132] As shown in FIG. 16, when implementing the pivot position automatic adjustment function, first, the displacement vector V Ｐ which is the direction and amount of displacement of the pivot point, is calculated based on the following formula (step S1).

[0133] V Ｔ = T ｎ - T ｐ α = |P ｐ - T ｐ | / L Ｔ V Ｐ = (1 - α)V Ｔ Note that the basic concept for calculating the displacement vector V Ｐ is the same as that described above using FIG. 13.

[0134] Next, it is determined whether both of the following two conditions are satisfied: the interference margin of the robot arm during operation is below a predetermined threshold, and the operating direction of the end effector EE is a direction that reduces the interference margin of the robot arm during operation (step S2).

[0135] Here, the interference margin of the robot arm during operation can be determined by modeling the robot arm. That is, in this embodiment, at least a part of each of the multiple robot arms 3 is modeled. For example, as shown in Figure 19, the model can be such that at least a part of the robot arm 3 is surrounded by a capsule-shaped virtual model. The part of the robot arm 3 that is modeled may include at least a part of the translational movement mechanism 35. Furthermore, at least a part of the virtual model of the robot arm 3 may be set as a reference part. In Figure 19, the reference part is represented by a capsule shown by a solid line. The reference part may be selected from the part where adjacent robot arms 3 are expected to be most likely to come into close proximity during treatment. For example, a part of the translational movement mechanism 35 may be selected as the reference part. Alternatively, the entire robot arm 3 may be modeled by covering each component constituting the robot arm 3 with each capsule.

[0136] Figure 20 shows an example of calculating the distance between two capsule models. A capsule model is given by the sweep volume of a sphere of radius r when it is moved in a straight line from point P to point Q. Interference checking with capsule models is performed by setting the radius and line segment of one capsule to r. １ and P １ Q １ Let the radius and line segment of the other capsule be r. ２ and P ２ Q ２ In this case, the line segment P of the two capsules １ Q １ and line segment P ２ Q ２ Find the distance L between the two capsules, and the distance L is the sum of the radii of the two capsules (r １ +r ２ Interference is determined when the distance L is less than or equal to the sum of the radii of the two capsules (r １ +r ２ If it is greater than ), there is an interference margin (L - (r) between the robot arms. １ +r ２ It is determined that )) exists.

[0137] As described above, in step 2, it is determined whether both the first condition, that the interference margin of the robot arm in operation is below a predetermined threshold, and the second condition, that the direction of movement of the end effector EE is in a direction that reduces the interference margin of the robot arm in operation, are met. The reason for this is as follows: If the determination is made based only on the first condition, that the interference margin of the robot arm in operation is below a predetermined threshold, the pivot point will be moved even if the direction of movement of the end effector EE increases the interference margin of the robot arm in operation (or the interference margin does not change), resulting in unnecessary displacement of the pivot point. Also, if the determination is made based only on the second condition, that the direction of movement of the end effector EE is in a direction that reduces the interference margin of the robot arm in operation, the pivot point will be moved even if there is still sufficient interference margin for the robot arm in operation, resulting in unnecessary displacement of the pivot point in this case as well. Since displacement of the pivot point results in displacement of the port member, even if the displacement of the pivot point is within the allowable displacement range, in step S2, the first and second conditions described above are set as AND conditions to prevent unnecessary displacement of the pivot point that does not contribute to expanding the operating range of the end effector by avoiding interference.

[0138] In step S2, if at least one of the two conditions described above is not met, the position of the pivot point is not changed (step S3). That is, the target position P of the pivot point. ｎ The current position P of the pivot point ｐ Controlling the robot arm as the same thing (P ｎ = P ｐ ).

[0139] On the other hand, in step S2, if both of the above two conditions are met, the current position P of the pivot point ｐ and displacement vector V Ｐ The target position P of the pivot point is determined using ｎ Calculate (step S4).

[0140] Next, the target position P of the pivot point determined in step S4.ｎ However, the initial position P of the pivot point ０ Allowable shift amount L from Ｐ It is determined whether the following conditions apply (step S5). Note that the allowable displacement amount L Ｐ For example, set the radius to 20 mm. In this case, the spatial region in which the pivot point can be set is the initial position P of the pivot point. ０ This forms a spherical region with a radius of 20 mm at its center.

[0141] In step S5, the target position P of the pivot point ｎ However, the initial position P of the pivot point ０ Allowable shift amount L from Ｐ If it is determined that the value exceeds a certain limit, the position of the pivot point will not be changed (step S3). That is, the target position P of the pivot point. ｎ The current position P of the pivot point ｐ Change it and apply it to the control of the robot arm (P ｎ = P ｐ ).

[0142] On the other hand, in step S5, the target position P of the pivot point determined in step 4 is ｎ However, the initial position P of the pivot point ０ Allowable shift amount L from Ｐ If the following is determined, the target position P of the pivot point determined in step 4 ｎ The robot arm is controlled using this method.

[0143] The control procedure shown in the flowchart in Figure 16 above is repeated at a predetermined fixed period. This predetermined fixed period may be determined based on the control period for controlling the robot arm (for example, several msec). For example, a value several times the control period for controlling the robot arm may be used as the period for repeatedly executing the control procedure shown in the flowchart in Figure 16. Figure 21 is a flowchart showing another example of a control procedure for performing the automatic pivot position adjustment function.

[0144] In the flowchart shown in Figure 21, step S23 is added between step S2 and step S3 compared to the flowchart shown in Figure 16. In the flowchart shown in Figure 21, the contents of the steps other than step 23 (i.e., steps 1, 2, 3, 4, and 5) are the same as those in the flowchart shown in Figure 16.

[0145] In step 23 of the flowchart shown in Figure 21, the first condition is that the interference margin of the robot arm during operation is greater than or equal to a second threshold, which is different from a predetermined threshold (first threshold) in step S2, and the direction of the pivot point shift is the initial position P of the pivot point. ０ It is determined whether both conditions are met, including the second condition that the direction is back to the original position. By setting a predetermined threshold (first threshold) in step S2 and the second threshold in step 23 to different values, the timing at which the pivot point begins to shift and the timing at which the pivot point begins to return to its original position are not simultaneous, thereby ensuring that the interference avoidance effect is more reliably achieved. Typically, by making the second threshold larger than the first threshold, interference can be prevented from occurring when the pivot point is returned to its original position.

[0146] In step S23, if at least one of the two conditions described above is not met, the position of the pivot point is not changed (step S3). That is, the target position P of the pivot point. ｎ The current position P of the pivot point ｐ Controlling the robot arm as the same thing (P ｎ = P ｐ ). On the other hand, in step S23, if both of the above two conditions are met, the current position P of the pivot point ｐ and displacement vector V Ｐ The target position P of the pivot point is determined using ｎ Calculate (step S4).

[0147] In the control procedure shown in Figure 21, step S23 is performed by adjusting the current position P of the pivot point using the previously performed automatic pivot position adjustment function. ｐ The initial position P ０If it is deviated from the pivot point, the current position P ｐ As close to the initial position P as possible ０ This is a step to return to the direction. In other words, in the control procedure without step S23 (Figure 16), if the determination in step S2 is NO, the procedure proceeds immediately to step 3 and the position of the pivot point is not changed. In contrast, in the control procedure shown in Figure 21, even if the determination in step S2 is NO, if the two conditions in step S23 are met, the procedure proceeds to step S4 and the target position P of the pivot point is changed. ｎ Calculate the target position P of the pivot point in step 5. ｎ However, the initial position P of the pivot point ０ Allowable shift amount L from Ｐ If the following is determined, the target position P of the pivot point determined in step 4 ｎ The robot arm is controlled using this method. This allows the pivot point's current position P to be adjusted by the previously implemented automatic pivot position adjustment function. ｐ The initial position P ０ If it is deviated from the pivot point, the current position P ｐ Initial position P ０ It can be returned in that direction.

[0148] Next, the verification results when the above-mentioned automatic pivot position adjustment function is applied to four cases with different robot arm states will be explained with reference to Figures 22 to 29. Figures 22 and 23 relate to the first case, Figures 24 and 25 relate to the second case, Figures 26 and 27 relate to the third case, and Figures 28 and 29 relate to the fourth case.

[0149] When verifying the automatic pivot position adjustment function using the first to fourth examples, the simulation was performed assuming that the end effector EE (more specifically, the tool center point TCP) moves within the HZ plane, where the vertical direction is the Z-axis and the direction roughly corresponding to the alignment of pivot points projected onto the XY plane is the H-axis. In actual surgical robots, the end effector EE moves in three-dimensional space, but from the perspective of interference between robot arms, the movement of the robot arms (especially the translational movement mechanism) when moving the end effector EE within the HZ plane is critical. Therefore, in the simulation for verification, the movement of the end effector EE was limited to the HZ plane.

[0150] Furthermore, in this verification, when interference occurred with the robot arm (virtual model) under evaluation without the automatic pivot position adjustment function, the positions that the end effector could reach (destination points) when the end effector was moved in one direction toward a target point on a circle of a predetermined radius in the HZ plane, centered on the position of the tip of the shaft of the surgical instrument attached to the robot arm under evaluation, were displayed at predetermined intervals. In Figure 23, etc., the white circles indicate positions (destination points) that can be reached without the automatic pivot position adjustment function, and the black circles indicate positions (destination points) that become reachable with the automatic pivot position adjustment function. In Figure 23, etc., the shaft portion 43 of the surgical instrument (virtual model) attached to the robot arm under evaluation is shown by a thick line.

[0151] In the first example (Figures 22 and 23), the robot arm 3A does not interfere with other robot arms, etc., and can move freely without its movement being restricted, so the range of motion of the tip (end effector) of the shaft portion 43 of the surgical instrument is not reduced.

[0152] On the other hand, because the tip of robot arm 3B is located close to robot arm 3C, moving the tip of robot arm 3B, especially the translational movement mechanism (linear axis), to the right or diagonally downward to the right in the diagram may cause interference with robot arm 3C. In other words, the movement of the tip of robot arm 3B to the right or diagonally downward to the right in the diagram is restricted. As a result, the movement of the tip of the shaft portion 43 of the surgical instrument attached to robot arm 3B (end effector) to the left or diagonally upward to the left in the diagram is restricted, and the range of motion of the end effector is reduced.

[0153] In situations where interference occurs in the robot arm 3B, using the automatic pivot position adjustment function allows the end effector to move to a part of the area to the left or diagonally upper left in the diagram (indicated by the black circle) that the end effector could not reach without the automatic pivot position adjustment function.

[0154] Robot arm 3C is an arm equipped with an endoscope (camera CAM) as a surgical instrument. Robot arm 3C is sandwiched between robot arms 3B and 3D, and if robot arm 3C, especially its translational movement mechanism (linear axis), is moved to the left or diagonally upward to the left in the diagram, interference with robot arm 3B occurs. In other words, the movement of robot arm 3C is restricted to the left or diagonally upward to the left in the diagram. As a result, the tip of the shaft portion 43 of the surgical instrument attached to robot arm 3C (end effector) cannot be moved to the right or diagonally downward to the right in the diagram, and the range of motion of the end effector is reduced.

[0155] Similarly, moving the robot arm 3C, particularly its translational movement mechanism (linear axis), to the right or diagonally downward to the right in the diagram causes interference with the robot arm 3D. In other words, the robot arm 3C is restricted to moving to the right or diagonally downward to the right in the diagram. Therefore, the tip of the shaft portion 43 of the surgical instrument attached to the robot arm 3C (end effector) is restricted to moving to the left or diagonally upward to the left in the diagram, thus reducing the range of motion of the end effector.

[0156] As a result, without the automatic pivot position adjustment function, the range of motion of the tip (end effector) of the shaft 43 of the surgical instrument attached to the robot arm 3C is limited to an extremely narrow area in the lower left direction of the figure (indicated by the white circle). In contrast, when the automatic pivot position adjustment function is applied to the control of the robot arm 3C, the end effector can move to a relatively wide area (indicated by the black circle) that covers almost all directions, which the end effector could not reach without the automatic pivot position adjustment function. For the robot arm 3C, the range of motion of the end effector is expanded by about 30 to 40 mm with the automatic pivot position adjustment function.

[0157] Because the tip of robot arm 3D is located close to robot arm 3C, moving the tip of robot arm 3D, especially the translational movement mechanism (linear axis), to the left or diagonally upward to the left in the diagram will cause interference with robot arm 3C. In other words, the movement of the tip of robot arm 3D to the left or diagonally upward to the left in the diagram is restricted. As a result, the movement of the tip of the shaft portion 43 of the surgical instrument attached to robot arm 3D (end effector) to the right or diagonally downward to the right in the diagram is restricted, and the range of motion of the end effector is reduced. In this situation, using the automatic pivot position adjustment function makes it possible to move to a part of the area to the right or diagonally downward to the right in the diagram (the part indicated by the black circle) that the end effector could not reach without the automatic pivot position adjustment function. For robot arm 3D, the range of motion of the end effector is expanded by about 30 to 40 mm by the automatic pivot position adjustment function.

[0158] In the robot arms 3C and 3D, the tip (end effector) of the surgical instrument shaft 43 is inserted to a relatively deep position inside the patient's body. The deeper the surgical instrument shaft 43 is inserted into the patient's body, the greater the effect of expanding the range of motion of the end effector in relation to the amount of pivot point displacement.

[0159] In the second example (Figures 24 and 25), an endoscope (camera CAM) is attached to the robot arm 3B, and the distance between the tip of the shaft portion 43 of the surgical instrument attached to the robot arm 3B (end effector) and the pivot point RC is relatively short. Similarly, the distance between the tip of the shaft portion 43 of the surgical instrument attached to the robot arms 3C and 3D (end effector) and the pivot point RC is also relatively short. Furthermore, in the second example, where the base of the sixth joint J36 of the robot arm 3A and the translational movement mechanism (linear axis) of the robot arm 3B are close together, the operating range of the end effector, particularly in the lower left region of the figure, is expanded for the robot arm 3A by applying an automatic pivot position adjustment function.

[0160] For the robot arm 3B equipped with an endoscope, the range of motion of the end effector is limited to a narrow area in the lower right of the diagram (indicated by the white circle) when the automatic pivot position adjustment function is not present. As mentioned above, in the robot arm 3B, the distance between the end effector and the pivot point RC is short, so even a slight movement of the end effector in the left-right direction in the diagram causes the robot arm 3B, especially the translational movement mechanism (linear axis), to move significantly, making interference with adjacent robot arms likely.

[0161] In contrast, by applying the automatic pivot position adjustment function, the operating range of the end effector can be expanded in almost all directions, as shown by the black circle. The expansion of the operating range of the end effector of robot arm 3B is approximately 30 to 40 mm.

[0162] Although the robot arm 3C appears to have ample operating range from Figure 24, as mentioned above, the distance between the pivot point RC and the end effector is short. Therefore, even a slight movement of the end effector in the left-right direction in the figure causes the robot arm 3C, especially the translational movement mechanism (linear axis), to tilt significantly and interfere with the adjacent robot arm. For this reason, without an automatic pivot position adjustment function, the operating range of the end effector is limited to the lower half of the figure (the area marked with a white circle).

[0163] In contrast, applying the automatic pivot position adjustment function expands the operating range of the end effector in a portion of the upper half of the diagram, as indicated by the black circle. The expansion of the end effector's operating range is approximately 20 to 30 mm. In cases where the distance between the pivot point and the end effector is short, the effect of expanding the end effector's operating range in relation to the amount of pivot point displacement is smaller compared to cases where the distance between the pivot point and the end effector is long.

[0164] Regarding the 3D robot arm, in the upper right region of the diagram, the calculation process for the inverse kinematics of arm control fails to find a solution, resulting in a region where the 3D robot arm cannot be operated and the end effector cannot be moved. In contrast, by applying the automatic pivot position adjustment function, the amount of movement of the translational movement mechanism (linear axis) is reduced compared to when the automatic pivot position adjustment function is not used, and the overall shape (configuration) of the arm changes. As a result, the inverse kinematics calculation finds a solution, and the operating range of the end effector is expanded (the area marked with a black circle).

[0165] The third example (Figures 26 and 27) is a case where the translational movement mechanisms (linear axes) of robot arms 3B and 3C are in close proximity to each other.

[0166] Regarding the robot arm 3A, its elbow 11 (see Figure 8) interferes with the positioner 7. As a result, there is a large area in the upper half of the figure that the end effector cannot reach. In this area, even when the automatic pivot position adjustment function was applied, there was almost no effect in expanding the operating range of the end effector.

[0167] Regarding robot arm 3B, since its tip is located close to the tip of robot arm 3C, moving the tip of robot arm 3B, particularly the translational drive mechanism (linear axis), to the right or diagonally upward in the diagram will cause interference with robot arm 3C. In other words, the movement of the tip of robot arm 3B to the right or diagonally upward in the diagram is restricted. As a result, the movement of the tip of the shaft portion 43 of the surgical instrument attached to robot arm 3B (end effector) to the left or diagonally downward in the diagram is restricted, and the range of motion of the end effector is reduced.

[0168] In this situation, applying the automatic pivot position adjustment function allows the end effector to move to a portion of the area to the left or diagonally downward to the left in the diagram (indicated by the black circle), which would not have been reachable without the automatic adjustment function. The expansion of the end effector's operating range is approximately 30 to 40 mm.

[0169] Regarding the robot arm 3C, since its tip is located close to the robot arm 3B, moving the tip of the robot arm 3C, particularly the translational movement mechanism (linear axis), to the left or diagonally downward to the left in the diagram will cause interference with the robot arm 3B. In other words, the movement of the tip of the robot arm 3C to the left or diagonally upward to the left in the diagram is restricted. As a result, the movement of the tip of the shaft portion 43 of the surgical instrument attached to the robot arm 3C (end effector) to the right or diagonally upward to the right in the diagram is restricted, and the range of motion of the end effector is reduced.

[0170] In this situation, applying the automatic pivot position adjustment function allows the end effector to move to a portion of the area to the right or diagonally upwards to the right in the diagram (indicated by the black circle), which would not have been reachable without the automatic adjustment function. The expansion of the end effector's operating range is approximately 30 to 40 mm.

[0171] Regarding the 3D robotic arm, its movement is not restricted in the first place, and the range of motion of the end effector has not been reduced.

[0172] The fourth example (Figures 28 and 29) is a case where the translational movement mechanism (linear axis) of robot arm 3C and the elbow 11 of robot arm 3D are in close proximity. For robot arms 3A and 3B, their movements are not restricted in the first place, and the operating range of the end effector is not reduced.

[0173] Regarding the robot arm 3C, its translational movement mechanism (linear axis) is located close to the elbow 11 of the robot arm 3D, which significantly restricts its movement. As a result, the range of motion of the tip (end effector) of the shaft 43 of the surgical instrument attached to the robot arm 3C is greatly reduced. When the automatic pivot position adjustment function is applied in this situation, the movement of the end effector is expanded in a portion of the area that the end effector could not reach without the automatic adjustment function (indicated by the black circle).

[0174] Regarding the 3D robot arm, its elbow 11 interferes with the translational movement mechanism (linear axis) of the 3C robot arm, resulting in a reduced operating range of the end effector in the upper right half of the figure. When the automatic pivot position adjustment function is applied in this situation, the end effector's movement is expanded in a portion of the area that the end effector could not reach without the automatic adjustment function (indicated by the black circle). Applying the automatic pivot position adjustment function suppresses the movement of the translational movement mechanism (linear axis) of the target robot arm, and as a result, changes in the overall shape (configuration) of the robot arm are also suppressed. This is thought to have resulted in a degree of interference avoidance effect for the elbow 11 of the robot arm.

[0175] Furthermore, in cases like the fourth example, where the translational movement mechanism (linear axis) of one robot arm 3C and the elbow 11 of the other robot arm 3D are in close proximity, the automatic constraint adjustment function (a function that dynamically changes the constraint conditions of redundant axes), which will be described later, is considered effective.

[0176] Next, referring to Figures 30 to 34, we will explain the results of verifying the four cases described above using other verification methods.

[0177] In the verification method described above with reference to Figure 23, the simulation was performed to move the end effector in one direction from an interfered state. In contrast, in the verification method described below with reference to Figures 30 to 34, the simulation is performed so that the direction in which the end effector moves changes regularly and sequentially, rather than in one direction.

[0178] In other words, as shown in the upper part of Figure 30, the position T of the end effector in the interfered state. ０ On the circumference of a circle with a predetermined radius centered on it, target points T are placed at 30-degree intervals. ｎ Place the objects. The first target point is T １ For example, the even-numbered target point T ２ These become the target points on the opposite side of the previous target point, and the odd-numbered target point T ３ The end effector is operated toward the target point so that it becomes the target point to the left (counterclockwise) of the target point from two attempts ago. If interference or an operating range error occurs on the way to the target point, the end effector will start moving toward the next target point from that point (the location where the interference occurred) (the state shown in the lower part of Figure 30).

[0179] Figure 31 shows the results of verifying the robot arm 3C of the first example (see Figure 22) using the verification method described with reference to Figure 30. It shows the case where the automatic pivot position adjustment function is not applied (left figure), the case where the automatic pivot position adjustment function is applied but the pivot position is not returned (first method) (center figure), and the case where the automatic pivot position adjustment function is applied but the pivot position is returned (second method) (right figure). The first method, where the pivot position is not returned, is the case where the control procedure shown in Figure 16 above is used, and the second method, where the pivot position is returned, is the case where the control procedure shown in Figure 21 above is used. In the upper figure, the position of the tool center point TCP is shown on the HZ plane, and in the lower figure, the pivot position is shown on the HZ plane.

[0180] As shown in the left-hand diagram of Figure 31, when the automatic pivot position adjustment function is not applied, the operating range of the end effector, i.e., the operating range of the tool center point TCP, is considerably limited. On the other hand, as shown in the center and right-hand diagrams of Figure 31, when the automatic pivot position adjustment function is applied, the operating range of the end effector (TCP) is significantly expanded compared to when the automatic pivot position adjustment function is not applied. By applying the automatic pivot position adjustment function, in both the first method where the pivot position is not returned (center diagram) and the second method where the pivot position is returned (right diagram), the operating range of the end effector (TCP) increases by approximately three times in terms of the trajectory area of ​​the pivot position compared to when the automatic pivot position adjustment function is not applied. Furthermore, in both the first method where the pivot position is not returned (center diagram) and the second method where the pivot position is returned (right diagram), it can be seen that the pivot position is sequentially moving (drifting) when the automatic pivot position adjustment function is applied.

[0181] The difference between the first method (without returning the pivot position) and the second method (with returning the pivot position) is that in the first method, interference occurs immediately after the end effector (TCP) turns around at the target point, meaning there is a point where the operability is poor (circled in the diagram), but such unnatural movement does not occur in the second method.

[0182] Figure 32 shows the results of the verification of the robot arm 3C in the second example (see Figure 24) using the verification method described with reference to Figure 30. In the second example as well, it can be seen that the operating range of the end effector (TCP) is expanded by applying the automatic pivot position adjustment function compared to when the automatic pivot position adjustment function is not applied. By applying the automatic pivot position adjustment function, the operating range of the end effector (TCP) is increased by approximately 1.7 times in terms of the trajectory area of ​​the pivot position compared to when the automatic pivot position adjustment function is not applied, both in the first method where the pivot position is not returned (center figure) and in the second method where the pivot position is returned (right figure).

[0183] Comparing the first method (where the pivot point is not returned) with the second method (where the pivot point is returned), it can be seen that the movement trajectory of the pivot point is relatively simple in the first method, while the movement trajectory of the pivot point is relatively complex in the second method.

[0184] In the second case, unlike the first case, both the first method (without returning the pivot position) and the second method (with returning the pivot position) show unnatural movements where the end effector (TCP) deviates from the target trajectory (circled in the diagram).

[0185] Figure 33 shows the results of the verification of the robot arm 3B in the third case (see Figure 26) using the verification method described with reference to Figure 30. In the third case as well, it can be seen that the operating range of the end effector (TCP) is expanded by applying the automatic pivot position adjustment function compared to when the automatic pivot position adjustment function is not applied. By applying the automatic pivot position adjustment function, the operating range of the end effector (TCP) is increased by approximately 1.5 times in terms of the trajectory area of ​​the pivot position compared to when the automatic pivot position adjustment function is not applied, both in the first method where the pivot position is not returned (center figure) and in the second method where the pivot position is returned (right figure).

[0186] One difference between the first method (without returning the pivot position) and the second method (with returning the pivot position) is that in the first method, the range of motion of the end effector (TCP) is successfully expanded in a certain area (circled), while in the second method, this expansion is not necessarily fully achieved. Therefore, in the third example, the first method is slightly more effective in expanding the range of motion of the end effector (TCP) than the second method.

[0187] In the third example, as in the second example, comparing the first method (where the pivot position is not returned) with the second method (where the pivot position is returned), it can be seen that the movement trajectory of the pivot point is relatively simple in the first method, while the movement trajectory of the pivot point is relatively complex in the second method.

[0188] Figure 34 shows the results of the verification of the robot arm 3C in the fourth example (see Figure 28) using the verification method described with reference to Figure 30. In the fourth example as well, it can be seen that the operating range of the end effector (TCP) is expanded by applying the automatic pivot position adjustment function compared to when the automatic pivot position adjustment function is not applied. By applying the automatic pivot position adjustment function, the operating range of the end effector (TCP) is increased by approximately 2.1 times in terms of the trajectory area of ​​the pivot position compared to when the automatic pivot position adjustment function is not applied, both in the first method where the pivot position is not returned (center figure) and in the second method where the pivot position is returned (right figure).

[0189] In the third case, unlike the first case, both the first method (without returning the pivot position) and the second method (with returning the pivot position) show unnatural movements where the end effector (TCP) deviates from the target trajectory (circled in the diagram).

[0190] Next, an example of the operation of the surgical robot system 10 with respect to the automatic constraint adjustment function described above will be explained with reference to Figures 35 to 41.

[0191] In the surgical robot system 10 according to this embodiment, the movement of the surgical instrument 40 to assume a target position and orientation during a procedure performed by following motion is achieved, for example, by an operation that includes the movement of joints including the nine axes of joints J31 to J39. The robot arm 3 has degrees of freedom that exceed the degrees of freedom required to control the position and orientation of the surgical instrument 40. In other words, the robot arm 3 has redundancy. Therefore, the set of rotational positions (joint positions) of the multiple joints of the robot arm 3 corresponding to a certain target position and target orientation of the shaft portion 43 of the surgical instrument 40 (or the configuration of the robot arm 3 determined by the set of angular positions) is not uniquely determined. For example, the operation of rotating the shaft portion 43 in the circumferential direction about its central axis C can be achieved not only by rotating the ninth joint J39 which is provided coaxially with the central axis C, but also by rotating the tip portion 32 of the arm body 30 in the circumferential direction about the central axis C. Therefore, the arm control unit 28 controls the rotational movement of the shaft portion 43 in the circumferential direction about the central axis C by combining the movement of the arm body 30 and the movement of the ninth joint J39. The arm control unit 28 then operates the arm body 30 and the ninth joint J39 in such a way as to satisfy the constraint conditions described below, which can achieve either a movement that rotates the shaft portion 43 in the circumferential direction about its central axis C, or a movement that maintains the shaft portion 43 in the same circumferential position without rotation.

[0192] In Figures 35 and 36, of the four robot arms 3, robot arm 3B and elements related to robot arm 3B are shown, while other elements are omitted as appropriate. Similarly, in Figure 37, of the four robot arms 3, robot arm 3A and elements related to robot arm 3A are shown, while other elements are omitted as appropriate.

[0193] In setting the constraint conditions described above, as shown in Figure 35, the arm control unit 28 first sets a reference point RD for each of the robot arms 3. As shown in Figure 11, the reference point RDB of robot arm 3B is located on the reference line RLB, which is the extension of the rotation axis R1 of the first joint J31 of robot arm 3B. The reference point RDA of robot arm 3A is located on the reference line RLA, which is offset to one side (+ 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 robot arm 3A (see also Figure 37). In this example of operation, 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 robot arm 3C is located on the reference line RLC, which is offset to the other side (- direction) of the first direction D1 with respect to the rotation axis R1 of the first joint J31 of robot arm 3C. Furthermore, the reference point RDD of the robot arm 3D is positioned on a reference line RLD that is offset to the other side (-direction) of the first direction D1 with respect to the rotation axis R1 of the first joint J31 of the arm 3D. In addition, 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 equipment of the surgical robot system 10, such as adjacent robot arms 3, or with the surrounding environment, such as assistants.

[0194] Next, as shown in Figure 36, the arm control unit 28 determines whether the length L of the perpendicular vh from the reference point RD to the central axis C of the shaft portion 43 that assumes the target orientation 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 vh is shorter than the lower limit length Lmin, it moves the position of the reference point RD on the reference line RL away from the central axis C of the shaft portion 43 so that the length of the perpendicular vh becomes longer than the predetermined length Lmin. If the arm control unit 28 determines that the length of the perpendicular vh is longer than the lower limit length Lmin, it does not perform this process. Alternatively, 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 vh and the position of the reference point RD on the reference line RL, without performing the above determination.

[0195] Next, as shown in Figure 35, 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, which extends in the longitudinal axis direction Dt, and intersects with the rotation axis R7 of the seventh joint J37.

[0196] As a result, the translational movement mechanism 35 and the instrument base 45 are constrained to swing around the axis Rv connecting the reference point RD and the remote center RC. Therefore, in order to achieve the movement of rotating the shaft portion 43 in the circumferential direction about its central axis C, the proportion of movement of rotating the tip portion 32 of the robot arm 3 in the circumferential direction about the central axis C can be reduced. Also, the proportion of movement of rotating the shaft portion 43 by rotating the ninth joint J39 can be increased. Therefore, the translational movement mechanism 35, which is connected perpendicular to the seventh joint J37, can be made to take an orientation facing outward from the reference point RD. This prevents the translational movement mechanism 35 and the instrument base 45 from taking an orientation that protrudes laterally (first direction D1) from the robot arm 3. As a result, interference with other equipment of the surgical robot system 10, such as adjacent robot arms 3, and the surrounding environment can be prevented. Furthermore, since the sixth link 86 of the arm body 30 can be positioned so that it faces the center of the robot arm 3 from the seventh joint J37, the link length of the arm body 30 can be used effectively, and the range of motion can be widened. In addition, since multiple robot arms 3 spread out in a fan shape from the arm base body 50, interference between adjacent robot arms can be reduced.

[0197] Furthermore, as shown in Figure 36, for example, if the shaft portion 43 swings around the remote center RC and approaches the reference point RD, the radius of rotation of the tip portion 32 of the robot arm 3 around the central axis C decreases during the operation of rotating the shaft portion 43 around the central axis C. As a result, the robot arm 3 becomes overly sensitive, and there is a possibility that the translational movement mechanism 35 and the equipment base 45 may experience large vibrations or a decrease in tracking ability due to the sudden movement of the robot arm 3. In this regard, if 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 becomes longer than a predetermined length Lmin. Therefore, it is possible to prevent the radius of rotation of the tip portion 32 of the robot arm 3 around the central axis C from decreasing when the shaft portion 43 approaches the reference point RD, thereby suppressing overly sensitive movements of the robot arm 3. Furthermore, if 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, it is possible to avoid the occurrence of overly sensitive movements.

[0198] In this way, the arm control unit 28 controls the robot arm 3 so that the shaft portion 43 of the surgical instrument 40 assumes the target position and target posture. Once 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 a predetermined lower limit length Lmin, and then executes the subsequent processing.

[0199] Furthermore, in the surgical robot system 10 according to this embodiment, the automatic constraint condition adjustment function described below can be implemented to more reliably avoid interference between the robot arm 3 and surrounding objects (for example, an adjacent robot arm 3).

[0200] As shown in the flowchart of Figure 38, the arm control unit 28 first determines the proximity distance between the reference parts of the virtual models of adjacent robot arms 3 (see Figures 19, 20(A), (B), and (C)) (step S1). For example, it determines the proximity distance between the reference part of the virtual model of the first robot arm 3A and the reference part of the virtual model of the second robot arm 3B.

[0201] Next, the arm control unit 28 determines whether the difference between the proximity distance determined in step S1 and the allowable minimum distance is greater than or equal to a predetermined threshold (step S2). Figure 39 shows a situation where the difference between the proximity distance d12 between the reference part of the first robot arm 3A and the reference part of the second robot arm 3B and the allowable minimum distance is less than the predetermined threshold, and the difference between the proximity distance d23 between the reference part of the second robot arm 3B and the reference part of the third robot arm 3C and the allowable minimum distance is greater than the predetermined threshold.

[0202] The arm control unit 28 selects a robot arm 3 to be adjusted if it determines that the difference between the proximity distance between the arms and the minimum allowable distance is smaller than a predetermined threshold (step S3). As the robot arm 3 to be adjusted, for example, the robot arm that is being operated by operation input from the operating device 2 (following operation) is selected from a pair of robot arms 3 whose proximity distance to each other has been determined.

[0203] By adjusting the robot arm 3 while it is in motion, the range of motion of the robot arm 3 can be expanded. In other words, if no adjustment is made, the robot arm 3 in motion would need to stop its movement, for example, when the proximity distance to other robot arms becomes smaller than the minimum allowable distance, in order to prevent interference with other robot arms. In contrast, by adjusting the robot arm 3 while it is in motion, it becomes possible to continue the movement to control the position and orientation of the surgical instrument 40 while avoiding interference with other robot arms.

[0204] Furthermore, for example, if the first robot arm 3A, which is in motion, approaches the second robot arm 3B, which is stationary, and the proximity distance between the arms becomes smaller than the minimum allowable distance, if the second robot arm 3B, which is stationary, is to be adjusted and its configuration is changed to increase the proximity distance with the first robot arm 3A, the proximity distance between the second robot arm 3B, which is the target of adjustment, and the adjacent third robot arm 3C may decrease. In this case, it may become necessary to change the configuration of the third robot arm 3C, which is an additional target of adjustment. Such a chain reaction of increasing robot arms to be adjusted should be avoided if possible, from the standpoint of preventing increased complexity of control. In this regard, by making the first robot arm 3A, which is in motion, rather than the second robot arm 3B, which is stationary, the target of adjustment, it is possible to prevent a chain reaction of increasing robot arms to be adjusted.

[0205] Furthermore, by adjusting the robot arm 3 while it is in motion, the possibility of vibration occurring in the robot arm 3 during adjustment can be reduced compared to adjusting the robot arm 3 while it is stationary, thereby suppressing the impact of vibration on surgery.

[0206] Furthermore, if both robot arms 3 are operating, the robot arm operating in the direction that shortens the proximity distance may be selected. Also, if both robot arms 3 are operating in the direction that moves them closer to each other, the following processing can be performed. First, a virtual straight line is assumed connecting the reference parts of the virtual models of the pair of robot arms 3. The velocity vector component in the direction along this virtual straight line is calculated for each of the pair of robot arms 3. If the calculated value of the velocity vector component of one robot arm 3 is greater 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.

[0207] 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 positive or negative direction in the first direction D1 shown in Figure 37.

[0208] Specifically, the direction of the offset adjustment is determined by moving the robot arm 3 to be adjusted on the model. That is, the offset amount is slightly changed by slightly shifting the reference point RD on the model in either the positive or negative direction in the first direction D1. This slightly changes the constraint conditions 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 Figure 40). 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 increases the proximity distance, that direction, i.e., the positive direction in the first direction D1, is determined as the adjustment direction. Conversely, 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 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. Furthermore, the initial direction in which the reference point RD is moved on the model can be set to a negative direction instead of the positive direction described above.

[0209] In the model calculation process in step S4 described above, only calculations are performed regarding the joint position of the ninth joint J39, which changes based on the change in the offset amount of the reference point RD. This can be done with a small amount of computation and requires only a short computation time.

[0210] Furthermore, the process in step S4 can also be performed by actually moving the robot arm 3. That is, in actual control rather than on the 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 conditions for the ninth joint J39, which is set as a redundant axis. As a result, the tool drive unit 38 of the tool holder 36 is driven and the ninth joint J39 rotates slightly. Along with the slight rotation of the ninth joint J39, the configuration of the robot arm 3 to be adjusted changes slightly. 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, then the positive (or negative) direction in the first direction D1 is determined as the adjustment direction. In contrast, 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 that reduces the proximity distance, then the negative (or positive) direction in the first direction D1 is determined as the adjustment direction for the offset amount. Even when the robot arm 3 is actually moved in step S4, only the redundant axis (9th joint J39) is driven, so the movement of the surgical instrument 40, which is controlled based on the operation input from the operating device 2, is not affected.

[0211] In step S4, once the direction of adjustment for the offset amount is determined, the offset amount of the reference point RD in the first direction D1 is adjusted in the determined adjustment direction (step S5). By adjusting (changing) the offset amount of the reference point RD, the constraint conditions for the ninth joint J39, which is set as a redundant axis, are changed. As a result, the instrument drive unit 38 of the instrument holder 36 is driven and the ninth joint J39 rotates. 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 constraint conditions, the configuration of the robot arm 3 to be adjusted changes, and this increases the proximity distance between the arms.

[0212] Next, it is determined whether the difference between the increased proximity distance between the arms (achieved by adjusting the offset amount of the reference point RD) and the minimum allowable distance is greater than or equal to a predetermined threshold (step S6). If the difference between the proximity distance between the arms and the minimum allowable distance is greater than or equal to the predetermined threshold, the adjustment of the offset amount of the reference point RD is terminated (step S6).

[0213] As described above, the arm control unit 28 controls the instrument drive unit 38 of the instrument holder 36 to rotate the ninth joint J39 by adjusting the offset amount of the reference point RD, thereby maintaining the proximity distance between the robot arms 3 at or above the minimum allowable distance. As previously stated, the ninth joint J39 is set as a redundant axis, so even if the constraint conditions change due to the change in the offset amount of the reference point RD, and as a result the ninth joint J39 is rotated, the resulting impact on the movement of the surgical instrument 40 can be avoided.

[0214] Figure 41 shows how interference between the third robot arm 3C and the fourth robot arm 3D is avoided by the control method according to this embodiment described above. In the example shown in Figure 41, the third robot arm 3C is moving toward the fourth robot arm 3D while the fourth robot arm 3D is stationary (step t). The arm control unit 28 determines the proximity distance between the reference part of the third robot arm 3C and the reference part of the fourth robot arm 3D based on virtual models of the robot arms 3C and 3D (see Figure 19) (step S1 in Figure 38). As the third robot arm 3C approaches the fourth robot arm 3D, the proximity distance between the reference part of the model of the third robot arm 3C and the reference part of the model of the fourth robot arm 3D gradually decreases (step t+1).

[0215] When the arm control unit 28 detects that the third robot arm 3C is approaching the fourth robot arm 3D and the difference between the proximity distance between the reference parts of the two models and the minimum allowable distance falls below a threshold, it proceeds to adjust the offset amount of the reference point RD of the third robot arm 3C (step t+2). Specifically, it first selects the robot arm whose offset amount will be adjusted (step S3 in Figure 38). In the example shown in Figure 41, 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 target for adjustment.

[0216] Next, the arm control unit 28 calculates the adjustment direction for the offset amount of the third robot arm 3C, which has been selected as the adjustment target (step S4 in Figure 38). Specifically, the offset of the third robot arm 3C on the model is moved slightly in one direction (for example, the positive direction) in the first direction D1 shown in Figure 37. If this increases the proximity distance between the reference part of the third robot arm 3C and the reference part of the fourth robot arm 3D on the model, that direction (the positive direction) is determined as the adjustment direction for the offset amount. Conversely, if the proximity distance decreases, the other direction (the negative direction) in the first direction D1 is determined as the adjustment direction for the offset amount of the third robot arm 3C.

[0217] Next, the offset amount of the third robot arm 3C is adjusted in the calculated adjustment direction (step S5 in Figure 38). As a result, the third robot arm 3C moves away from the fourth robot arm 3D (step t+2). The arm control unit 28 determines whether the proximity distance between the reference parts of the models of the third robot arm 3C and the fourth robot arm 3D has become greater than or equal to the minimum allowable distance (step S6 in Figure 38), and when this proximity distance becomes greater than or equal to the minimum allowable distance, the adjustment of the offset amount of the third robot arm 3C is terminated.

[0218] Through the above operations, the proximity distance between the reference parts of the models of the third robot arm 3C and 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, it is possible to avoid the surgical robot 1 stopping (locking) due to interference between the robot arms, for example, and to ensure the continuity of the surgery.

[0219] Furthermore, since the proximity distance between the reference parts of the adjacent robot arms 3C and 3D is automatically maintained by the arm control unit 28 to be above the minimum allowable distance, interruptions to the control of the position and orientation of the end effector by the robot arm 3C during operation (following motion) can be avoided. This ensures the continuity of the procedure performed by the operator S.

[0220] As mentioned above, the object to be avoided for interference is typically the adjacent robot arm 3. However, other devices that make up the patient-side unit, such as equipment other than the robot arm 3 or a treatment assistant, can also be targeted for interference avoidance by providing appropriate object detection means. An appropriate object detection means is a proximity sensor 60 (see Figure 8) placed at an appropriate position on the robot arm 3 to detect proximity to surrounding objects. The proximity sensor 60 can be an inductive proximity sensor, a magnetic proximity sensor, an optical proximity sensor, an ultrasonic proximity sensor, a capacitive proximity sensor, etc. 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, and performs the interference avoidance control described above based on the determined distance. Alternatively, an imaging device may be installed to image the surrounding object, and the images from this imaging device may be analyzed using artificial intelligence technology such as machine learning to determine the distance between the target robot arm 3 and the surrounding object.

[0221] Furthermore, for objects other than the robot arm 3 that are to be avoided, the spatial region in which such objects exist, or the spatial region in which such objects may exist, may be pre-modeled as a no-entry zone. The no-entry zone may be set, for example, as the spatial region in which equipment other than the robot arm 3 that constitutes the surgical robot 1 exists, or as the spatial region in which the body of a surgical assistant may exist during surgery. The model of the no-entry zone may be defined in the slave 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 zone by calculation without using proximity sensors or the like. Alternatively, a method using the detection results of proximity sensors and a method using the model of the no-entry zone can be used in combination.

[0222] As described above, the surgical robot system and its control method according to this embodiment, which is equipped with an automatic redundancy condition adjustment function, can reliably avoid interference between the robot arm and objects surrounding the robot arm, thereby reliably ensuring the continuity of surgery performed by the operator (surgeon) S.

[0223] Furthermore, the control method for the surgical robot system according to this embodiment, which includes the pivot position automatic adjustment function and the redundancy condition automatic adjustment function described above, can be implemented by a computer program. The computer program may include computer code arranged to instruct the computer to execute one or more functions of the control method described above. The computer program and / or the code for executing such a control method may be provided on one or more computer-readable media. The computer-readable media may be transient or non-transient. The computer-readable media may be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, or a propagation medium for data transmission for downloading code over the Internet, for example. Alternatively, the computer-readable media may take the form of one or more physical computer-readable media such as semiconductors or solid-state memory, magnetic tape, removable computer diskettes, random access memory (RAM), read-only memory (ROM), hard magnetic disks, CD-ROMs, CD-R / Ws, DVDs, and other optical disks.

[0224] Furthermore, the functions of the components disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), 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 circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0225] As described above, the surgical robot system and control method according to this embodiment make it possible to prevent or mitigate the limitation of the robot arm's movement and the resulting reduction in the range of motion of surgical instruments by applying the automatic pivot position adjustment function.

[0226] Furthermore, according to the surgical robot system and control method of this embodiment, by applying an automatic redundancy condition adjustment function in addition to the automatic pivot position adjustment function, it is possible to more reliably prevent or mitigate the limitation of the robot arm's movement and the resulting reduction in the range of motion of surgical instruments.

[0227] Furthermore, based on the judgment that the pivot point RC should not be moved as much as possible during surgery (especially during following movements), the automatic constraint adjustment function may be applied preferentially over the automatic pivot position adjustment function. In other words, if the range of motion of the surgical instrument 40 is restricted due to interference between robot arms 3, the automatic constraint adjustment function may be used first to try to avoid the restriction on the range of motion of the surgical instrument 40, and if the restriction on the range of motion of the surgical instrument 40 can be avoided in this way, the automatic pivot position adjustment function may not be applied. On the other hand, if the automatic constraint adjustment function cannot avoid the restriction on the range of motion of the surgical instrument 40 at all, or cannot avoid it completely, the automatic pivot position adjustment function may be applied instead of the automatic constraint adjustment function, or in addition to the automatic constraint adjustment function, to avoid the restriction on the range of motion of the surgical instrument 40.

[0228] This disclosure also includes the following aspects: (Aspect 1) Aspect 1 of this disclosure is a surgical robot system comprising: a robot arm having a tip to which a surgical instrument having a longitudinal axis can be attached and a plurality of drive axes, the number of which is greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument; an operating device for receiving operator input for controlling the position and orientation of the surgical instrument; and a control device for controlling the robot arm based on the operator input, wherein the tip has an instrument drive unit for rotating 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 robot arm and objects present around the robot arm that is greater than or equal to a minimum allowable distance.

[0229] (Aspect 2) Aspect 2 of this disclosure is a surgical robot system according to Aspect 1, wherein when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold, 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.

[0230] (Aspect 3) Aspect 3 of this disclosure is a surgical robot system according to 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 for moving the surgical instrument along the longitudinal axis, and the reference portion includes at least a portion of the translational movement mechanism.

[0231] (Aspect 4) Aspect 4 of this disclosure is a surgical robot system according to 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 on the patient, and the number of the plurality of drive axes of the robot arm is greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument while at least a portion of the surgical instrument is inserted into the port member.

[0232] (Aspect 5) Aspect 5 of this disclosure is a surgical robot system according to 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.

[0233] (Aspect 6) Aspect 6 of this disclosure is a surgical robot system according to aspect 5, wherein the control device operates the robot arm on the arm model to determine a rotation direction that increases the proximity distance among two rotation directions around the longitudinal axis of at least a portion of the surgical instrument.

[0234] (Aspect 7) Aspect 7 of this disclosure is a surgical robot system according to aspect 5 or 6, wherein the robot arm has a translational movement mechanism for moving the surgical instrument along the longitudinal axis, and at least a portion of the robot arm is at least a portion of the translational movement mechanism.

[0235] (Aspect 8) Aspect 8 of this disclosure is a surgical robot system according to any one of aspects 1 to 7, wherein the object is another robot arm to which other surgical instruments can be attached, the operating device receives operator input for controlling the position and orientation of the surgical instruments attached to the robot arm and the position and orientation of the other surgical instruments attached to the other robot arm, and the control device controls the robot arm and the other robot arm based on the operator input.

[0236] (Aspect 9) Aspect 9 of this disclosure is a surgical robot system according to aspect 8, wherein the other robot arm has a tip to which the other surgical instrument having another longitudinal axis can be attached and a plurality of drive axes, the number of which is greater than the minimum degree of freedom required to control the position and orientation of the other surgical instrument, the tip of the other robot arm has a separate instrument drive unit that rotates at least a portion of the other surgical instrument around the other 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.

[0237] (Aspect 10) Aspect 10 of this disclosure is a surgical robot system according to aspect 9, wherein the control device selects the robot arm that is operating by the operation input from among the robot arm and the other robot arms as the robot arm to be adjusted, and adjusts the proximity distance by operating the instrument drive unit of the robot arm to be adjusted.

[0238] (Aspect 11) Aspect 11 of this 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.

[0239] (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 torsional joint disposed at the base end, and a bending joint disposed between the tip 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, fix the orientation of the rotation axis of the bending joint with respect to the reference plane, set a predetermined center point, set a reference point on a reference line which is the extension of the rotation axis of the torsional joint or a line offset in the direction perpendicular to the extension, control the robot arm to position the longitudinal axis at the center point and the reference plane at the reference point, and control the operating direction and amount of the instrument drive unit by adjusting the offset amount of the reference point in the direction perpendicular to the extension to maintain the proximity distance at or above the allowable minimum distance.

[0240] (Aspect 13) Aspect 13 of this disclosure is the surgical robot system according to aspect 12, wherein the direction orthogonal to the extension line is the horizontal direction.

[0241] (Aspect 14) Aspect 14 of this disclosure is a surgical robot system according to aspect 12 or 13, further comprising an arm base for holding the base end of the robot arm and the base end of another robot arm, wherein the arm base has a longitudinal axis and the direction perpendicular to the extension line is parallel to the longitudinal axis of the arm base.

[0242] (Aspect 15) Aspect 15 of this disclosure is a method for controlling a surgical robot system, the method comprising: a robot arm having a tip portion to which a surgical instrument having a longitudinal axis is attached and a plurality of drive axes, the number of the plurality of drive axes being greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument; an operating device for receiving operator input for controlling the position and orientation of the surgical instrument; and a control device for controlling the robot arm based on the operator input, wherein an instrument drive unit constituting at least a part of the tip portion rotates at least a part of the surgical instrument around the longitudinal axis, and the instrument drive unit is controlled to maintain the proximity distance between the robot arm and objects present around the robot arm at or above the minimum allowable distance.

[0243] (Aspect 16) Aspect 16 of this disclosure is a control method for a surgical robot system according to aspect 15, wherein when the difference between the proximity distance and the minimum allowable distance becomes smaller than a predetermined threshold, the instrument drive 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.

[0244] (Aspect 17) Aspect 17 of this disclosure is a computer-readable medium storing computer-readable instructions, wherein when the computer-readable instructions are executed by a processor of a surgical robot system, the processor causes the processor to execute a control method for the surgical robot system, the surgical robot system comprising: a robot arm having a tip portion to which a surgical instrument having a longitudinal axis is attached and a plurality of drive axes, the number of the plurality of drive axes being greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument; an operating device for receiving operator input for controlling the position and orientation of the surgical instrument; and a control device for controlling the robot arm based on the operator input, wherein the control method rotates at least a portion of the surgical instrument around the longitudinal axis by an instrument drive unit constituting at least a portion of the tip portion, and controls the instrument drive unit to maintain a proximity distance between the robot arm and objects present around the robot arm at or above a minimum allowable distance.

[0245] (Aspect 18) Aspect 18 of this disclosure is a computer-readable medium according to aspect 17, wherein the control method 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.

[0246] (Aspect 19) Aspect 19 of this disclosure is a surgical robot system comprising: a robot arm having a tip portion to which a surgical instrument can be attached and a plurality of drive axes, wherein the number of the plurality of drive axes is greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument; an operating device for receiving operator input for controlling the position and orientation of the surgical instrument; and a control device for controlling the robot arm based on the operator input, wherein the control device defines at least one of the plurality of drive axes as a redundant drive axis, controls the redundant drive axis based on the operator input and constraint conditions, and adjusts the constraint conditions to maintain a proximity distance between the robot arm and objects present around the robot arm that is greater than or equal to the minimum allowable distance.

[0247] (Aspect 20) Aspect 20 of this disclosure is a surgical robot system according to aspect 19, 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.

[0248] (Aspect 21) Aspect 21 of this disclosure is a surgical robot system according to 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.

[0249] (Aspect 22) Aspect 22 of this disclosure is a method for controlling a surgical robot system, the method comprising: a robot arm having a tip to which a surgical instrument is attached and a plurality of drive axes, wherein the number of the plurality of drive axes is greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument; an operating device for receiving operator input for controlling the position and orientation of the surgical instrument; and a control device for controlling the robot arm based on the operator input, wherein at least one of the plurality of drive axes is defined as a redundant drive axis, the redundant drive axis is controlled based on the operator input and constraint conditions, and the constraint conditions are adjusted to maintain the proximity distance between the robot arm and objects present around the robot arm at or above the minimum allowable distance.

[0250] (Aspect 23) Aspect 23 of this disclosure is a control method for a surgical robot system according to aspect 22, wherein the surgical instrument has a longitudinal axis, and at least a portion of the surgical instrument is rotated about the longitudinal axis by the redundant drive shaft.

[0251] (Aspect 24) Aspect 24 of this disclosure is a control method for a surgical robot system according to aspect 23, wherein 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.

[0252] (Aspect 25) Aspect 25 of this disclosure is a computer-readable medium storing computer-readable instructions, wherein when the computer-readable instructions are executed by a processor of a surgical robot system, the processor causes the processor to execute a control method for the surgical robot system, the surgical robot system comprising: a robot arm having a tip to which surgical instruments are attached and a plurality of drive axes, the number of the plurality of drive axes being greater than the minimum degree of freedom required to control the position and orientation of the surgical instruments; an operating device for receiving operator input for controlling the position and orientation of the surgical instruments; and a control device for controlling the robot arm based on the operation input, wherein the control method defines at least one of the plurality of drive axes as a redundant drive axis, controls the redundant drive axis based on the operation input and constraint conditions, and adjusts the constraint conditions to maintain a proximity distance between the robot arm and objects present around the robot arm at or above a minimum allowable distance.

[0253] (Aspect 26) Aspect 26 of this disclosure is a computer-readable medium according to aspect 25, wherein the surgical instrument has a longitudinal axis, and the control method rotates at least a portion of the surgical instrument around the longitudinal axis by the redundant drive shaft.

[0254] (Aspect 27) Aspect 27 of this disclosure is a computer-readable medium according to 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.

[0255] 1 Surgical robot 2 Operating device 3, 3A, 3B, 3C, 3D Robot arm 10 Surgical robot system 28 Arm control unit (control device) 32 Tip of robot arm 35 Translational movement mechanism 36 Instrument holder 40 Surgical instrument 38 Instrument drive unit 43 Shaft of surgical instrument 60 Proximity sensor C Center axis of shaft (longitudinal axis of surgical instrument) J31-J39 Joint (drive axis) R1-R9 Rotation axis RC Remote center (pivot point) RD Reference point RL, RLA, RLB Reference line RP Reference plane S Operator (surgeon) P Patient

Claims

1. A surgical robot system comprising: a robot arm having a tip portion capable of attaching a surgical instrument having a longitudinal axis and a plurality of drive axes; an operating device that receives operator input for controlling the position and orientation of the surgical instrument; and a control device that controls the robot arm based on the operator input, wherein the control device controls the robot arm based on the operator input while maintaining the longitudinal axis passing through a pivot point when a portion of the surgical instrument is inserted into the patient's body through an opening formed in the patient's body; and when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the control device moves the pivot point to a position that avoids at least a portion of the restriction on the movement of the robot arm and expands the range of motion of the surgical instrument.

2. The surgical robot system according to claim 1, wherein when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the direction and amount of movement when moving the set position of the pivot point are determined based on the amount and direction of movement of the tip of the surgical instrument when the robot arm is controlled based on the operation input to move the tip of the surgical instrument.

3. The surgical robot system according to claim 1 or 2, wherein the situation in which the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced is related to controlling the movement of the robot arm to avoid interference between the robot arm and other objects.

4. The surgical robot system according to claim 3, further comprising another robot arm different from the robot arm, wherein the other object includes the other robot arm.

5. The surgical robot system according to claim 4, wherein the control device generates a first arm model by modeling at least a portion of the robot arm and generates a second arm model by modeling at least a portion of the other robot arm, and the situation in which the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced is related to the proximity distance between the first arm model and the second arm model becoming smaller than the minimum allowable distance.

6. The surgical robot system according to claim 1 or 2, wherein the situation in which the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced is such that the interference margin of the robot arm during operation is below a predetermined threshold, and the direction of movement of the tip of the surgical instrument is such that the interference margin of the robot arm during operation is reduced.

7. The surgical robot system according to claim 1 or 2, wherein the control device moves the pivot point from its initial setting position when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, and then moves the pivot point in the direction of the initial setting position when the movement of the robot arm is not restricted.

8. The surgical robot system according to claim 1 or 2, wherein the control device moves the pivot position from its initial setting position when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, and does not move the pivot point in the direction of the initial setting position when the movement of the robot arm is not restricted.

9. The surgical robot system according to claim 1 or 2, wherein the following equation Y = X × A / (A + B) is satisfied, where X is the amount of movement of the tip of the surgical instrument by controlling the robot arm based on the operation input, Y is the amount of movement of the pivot point to the set position in the direction in which the operating range of the surgical instrument is expanded, A is the distance from the pivot point to the reference point set on the longitudinal axis of the surgical instrument on the opposite side of the tip of the instrument with respect to the pivot point, and B is the distance from the pivot point to the tip of the instrument.

10. The surgical robot system according to claim 9, wherein the tip of the robot arm has a translational movement mechanism for moving the surgical instrument along the longitudinal axis, and the reference point corresponds to the rear end of the translational movement mechanism.

11. The surgical robot system according to claim 9, wherein the tip of the robot arm includes a translational movement mechanism for moving the surgical instrument along the longitudinal axis, the plurality of drive axes include a tip-side drive axes that rotatably connect the translational movement mechanism to other parts of the tip of the robot arm, and the reference point corresponds to the tip-side drive axes.

12. The surgical robot system according to claim 1 or 2, wherein the number of the plurality of drive axes of the robot arm is greater than the minimum degree of freedom required to control the position and orientation of the surgical instrument, the control device defines at least one of the plurality of drive axes as a redundant drive axis, controls the redundant drive axis based on the operation input and constraint conditions, and adjusts the constraint conditions to maintain a proximity distance between the robot arm and objects present around the robot arm that is greater than or equal to the minimum allowable distance.

13. The surgical robot system according to claim 12, wherein the redundant drive shaft rotates at least a portion of the surgical instrument around the longitudinal axis.

14. The surgical robot system according to claim 13, 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.

15. A method for controlling a surgical robot system, wherein the surgical robot system comprises: a robot arm having a tip portion capable of mounting a surgical instrument having a longitudinal axis and a plurality of drive axes; an operating device that receives operator input for controlling the position and orientation of the surgical instrument; and a control device that controls the robot arm based on the operator input, wherein, when a part of the surgical instrument is inserted into the patient's body through an opening formed in the patient's body, the robot arm is controlled based on the operator input while maintaining the state in which the longitudinal axis passes through a pivot point set in the opening; and when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the setting position of the pivot point is moved in a direction in which at least a part of the restriction on the movement of the robot arm is avoided and the range of motion of the surgical instrument is expanded.

16. The control method for a surgical robot system according to claim 15, wherein when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the direction and amount of movement when moving the set position of the pivot point are determined based on the amount and direction of movement of the tip of the surgical instrument when the robot arm is controlled based on the operation input to move the tip of the surgical instrument.

17. A computer-readable medium storing computer-readable instructions, wherein when the computer-readable instructions are executed by the processor of a surgical robot system, the processor causes the processor to execute a control method for the surgical robot system, the surgical robot system comprising: a robot arm having a tip portion capable of attaching a surgical instrument having a longitudinal axis and a plurality of drive axes; an operating device that receives operator input for controlling the position and orientation of the surgical instrument; and a control device that controls the robot arm based on the operator input, wherein the control method controls the robot arm based on the operator input while maintaining the state that the longitudinal axis passes through a pivot point set in the opening when a part of the surgical instrument is inserted into the patient's body through an opening formed in the patient's body, and when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the computer-readable medium moves the setting position of the pivot point in a direction that avoids at least a part of the restriction on the movement of the robot arm and expands the range of motion of the surgical instrument.

18. The computer-readable medium according to claim 17, wherein when the movement of the robot arm is restricted and the range of motion of the surgical instrument is reduced, the direction and amount of movement when moving the set position of the pivot point are determined based on the amount and direction of movement of the tip of the surgical instrument when the robot arm is controlled based on the operation input to move the tip of the surgical instrument.

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