A method for adjusting the working space of a surgical arm

Abstract

The present invention discloses a method for adjusting the working space of a surgical arm, comprising the steps of: obtaining the current working space of the surgical arm; determining the target pose of the end surgical instrument according to the real-time pose of the end of the master robotic arm; judging whether the surgical arm is within its current working space when the end surgical instrument is at its target pose, if so, controlling the joints of the surgical arm to move to their target poses, otherwise driving the redundant pitching joint in the adjustment arm to adjust its working space, and at the same time keeping the pose of the end surgical instrument unchanged through the synchronous cooperation actions of the remaining joints of the slave robotic arm. The present invention can autonomously judge the working space of the surgical arm and make appropriate adjustments to the working space, effectively expanding its operating range without interrupting the operation, ensuring the continuity and fluency of the operation, and improving the overall safety.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a method for adjusting the working space of a surgical arm. Background Art

[0002] At present, minimally invasive surgery has basically replaced open surgery as the main development direction in the field of surgical medicine. Compared with traditional open surgery, minimally invasive surgery has the advantages of small trauma, mild pain, and quick recovery. With the development of robot technology, minimally invasive surgery based on a robot-assisted system, represented by the Da Vinci surgical robot, has gradually matured and been widely used.

[0003] A laparoscopic surgical robot is a master-slave teleoperation system, including a master manipulator and a slave manipulator. Among them, the master manipulator is the manipulator directly controlled by the operator, and the slave manipulator includes an adjustment arm, a surgical arm, and an end surgical instrument. The operator can control the slave manipulator by operating the master manipulator, so as to perform surgery on the patient using the end surgical instrument.

[0004] During the operation, the slave manipulator performs corresponding surgical actions following the movement of the master manipulator. For some special surgical actions, it may be necessary for the surgical arm to be in a state close to full extension or retraction for surgery. During the subsequent surgery, it is inevitable that due to the limit of the pitch joint of the slave manipulator, the end surgical instrument cannot reach the lesion. At this time, the surgery may need to be temporarily aborted, and the bedside nurse needs to re-adjust the pose of the adjustment arm, and even needs to re-plan the punching position on the patient's body surface to carry out the surgery. The above process undoubtedly destroys the continuity of the surgery, prolongs the surgery time, and increases the surgical risk and patient injury. Summary of the Invention

[0005] Object of the Invention: Aiming at the above deficiencies, the present invention provides a robot and a control method capable of dynamically adjusting the working space of a surgical arm during surgery.

[0006] Technical Solution:

[0007] A method for adjusting the working space of a surgical arm, comprising the steps of:

[0008] Obtaining the current working space of the surgical arm;

[0009] Determining the target pose of the end surgical instrument according to the real-time pose of the end of the master manipulator;

[0010] Judging whether the surgical arm is within its current working space when the end surgical instrument is at its target pose. If so, controlling the joints of the surgical arm to move to their target poses. Otherwise, driving the redundant pitch joints in the adjustment arm to move to adjust its working space, and at the same time, making the pose of the end surgical instrument unchanged through the synchronous cooperation actions of the other joints of the slave manipulator.

[0011] The specific method for obtaining the current workspace of the surgical arm is as follows:

[0012] Calculate the motion range of the pitch joint of the surgical arm based on the mechanical structure design parameters, so as to obtain the current workspace of the surgical arm.

[0013] The specific method for obtaining the current workspace of the surgical arm is as follows:

[0014] Adjust the surgical arm to make the end surgical instrument perform pitch motion around the center of rotation of the remote center of motion to reach its minimum limit position and maximum limit position, thereby obtaining the motion range of the pitch joint and the current workspace of the surgical arm.

[0015] The specific operation of adjusting the surgical arm to make the end surgical instrument perform pitch motion around the center of rotation of the remote center of motion to reach its minimum limit position and maximum limit position is as follows:

[0016] Adjust the pitch joint to make the center lines of the connecting rods of the surgical arm coincide, and obtain the minimum limit position of the pitch joint;

[0017] Adjust the pitch joint to make the center lines of the connecting rods of the surgical arm perpendicular to each other, and obtain the maximum limit position of the pitch joint.

[0018] Set a motion buffer for the motion range of the pitch joint to obtain the set motion range of the pitch joint, and calculate the current workspace of the surgical arm based on this.

[0019] The range of the motion buffer is [0°, 10°].

[0020] The specific operation of determining whether the surgical arm is within its current workspace when the end surgical instrument is at its target pose is as follows:

[0021] Calculate the target positions of the joints of the surgical arm according to the target pose of the end surgical instrument and control the motion of each joint;

[0022] Real-time obtain the current position of the pitch joint of the surgical arm, and determine whether it is within its set motion range. If so, continue to control the motion of each joint; otherwise, adjust the workspace of the surgical arm.

[0023] The specific operation of adjusting the workspace of the surgical arm is as follows:

[0024] Calculate the current pose matrix of the center of rotation of the remote center of motion through forward kinematics of the robotic arm, and obtain the current positions of the joints of the robotic arm;

[0025] Judge the motion direction of the redundant pitch joint according to the current position of the pitch joint, and calculate the target position of the redundant pitch joint;

[0026] Based on the current pose matrix of the telecentric fixed point and the target position of the redundant pitch joint, calculate the target positions of the joints of the robotic arm while keeping the current pose of the telecentric fixed point unchanged, and calculate the position increments of the joints of the robotic arm in combination with the current positions of the joints of the robotic arm, and control the execution.

[0027] The determination of the target position of the redundant pitch joint is specifically as follows:

[0028] Set the periodic motion amount of the redundant pitch joint and periodically update the motion range of the pitch joint so that the current position of the pitch joint falls back into its updated motion range, and the target position of the redundant pitch joint can be determined.

[0029] The specific determination of whether the surgical arm is within its current workspace when the end surgical instrument is at its target pose is as follows:

[0030] Calculate the target positions of the joints of the surgical arm according to the target pose of the end surgical instrument;

[0031] Calculate and determine whether the target position of the pitch joint of the surgical arm is within its motion range. If so, control the motion of the joints of the surgical arm; otherwise, adjust the workspace of the surgical arm.

[0032] The adjustment of the workspace of the surgical arm is specifically as follows:

[0033] According to the target position and motion range of the pitch joint, calculate the target position of the redundant pitch joint, and then calculate the final target positions of the other joints of the robotic arm, and control the motion of the joints of the robotic arm.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention can autonomously judge whether the workspace of the surgical arm needs to be adjusted and can dynamically adjust its workspace, effectively expanding the surgical range without interrupting the operation.

[0036] 2. The present invention does not require manual intervention and adjustment by the bedside nurse, nor does it need to re-plan the punching positions on the patient's body surface, ensuring the continuity and smoothness of the operation and improving the overall safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the installation schematic diagram of the surgical arm of the present invention;

[0038] Figure 2 is the flow chart of dynamically adjusting the workspace of the surgical arm of the present invention;

[0039] Figure 3 is the schematic diagram of the minimum limit of the pitch joint;

[0040] Figure 4 Schematic diagram of the maximum limit of the pitching joint

[0041] Figure 5 Schematic diagram of the minimum limit of the pitching joint after adjustment

[0042] Figure 6 Schematic diagram of the maximum limit of the pitching joint after adjustment

[0043] Wherein, 1 is the adjustment arm, 2 is the surgical arm, 21 is the flipping joint, 22 is the first arm, 23 is the second arm, 24 is the third arm, 25 is the instrument arm, 3 is the redundant pitching joint, and 4 is the RCM point Detailed implementation manners

[0044] The present invention will be further clarified below in conjunction with the accompanying drawings and specific embodiments

[0045] As Figure 1 shown, it is a schematic structural diagram of the slave manipulator of the laparoscopic surgical robot in the present invention. The slave manipulator includes an adjustment arm 1, a surgical arm 2 and an end surgical instrument; the adjustment arm 1 is used to perform the positioning action and adjust the spatial position of the RCM point (i.e., the center of rotation point); the adjustment arm 1 includes a redundant pitching joint 3 for driving the surgical arm 2 to perform pitching motion; the surgical arm 2 includes a flipping joint 21, a pitching joint composed of multiple joints and linkages, and an instrument arm 25 mounted on the pitching joint. The pitching joint is used to drive the end surgical instrument at the end of the instrument arm 25 to perform pitching motion around the RCM point 4, so as to perform operations; in the present invention, the pitching joint of the surgical arm 2 is formed by the cooperation of 3 linkages and joints. The three linkages are the first arm 22, the second arm 23 and the third arm 24 in sequence. The first arm 22 is mounted in cooperation with the flipping joint 21, and the instrument arm 25 is mounted on the third arm 24 through a joint; usually, the movement range of the surgical arm 2 is a conical area with the RCM point 4 as the vertex. The angular range of the conical area is restricted by the limit of the pitching joint of the surgical arm 2. In the present invention, the movement range of the surgical arm 2 is generally a conical area with the RCM point 4 as the vertex, that is, the working space of the surgical arm 2

[0046] Figure 2 It is a flowchart of dynamically adjusting the working space of the surgical arm of the present invention. As Figure 2 shown, the method for dynamically adjusting the working space of the surgical arm of the present invention includes the following steps

[0047] (1) Obtain the current working space of the surgical arm

[0048] In one embodiment, the motion range of the pitching joint of the surgical arm 2 can be obtained according to the mechanical structure design parameters, so as to calculate the motion range of the end surgical instrument and obtain the current working space of the surgical arm; alternatively, the motion range of the end surgical instrument can be defined by adjusting the position of the pitching joint of the surgical arm 2, so as to obtain the current working space of the surgical arm, specifically as follows:

[0049] Adjust the pitching joint so that the center lines of the connecting rods of the first arm 22, the second arm 23 and the third arm 24 coincide, and record the position of the pitching joint at this time as its minimum limit position P relative to the zero position min ;

[0050] Adjust the pitching joint so that the center lines of the connecting rods of the first arm 22, the second arm 23 and the third arm 24 are perpendicular, and record the position of the pitching joint at this time as its maximum limit position P relative to the zero position max ;

[0051] In one embodiment, the zero position of the pitching joint is the position of the pitching joint when the redundant pitching joint is in the zero position and the instrument arm 25 is in the vertical state; the zero position of the redundant pitching joint is the position of the redundant pitching joint when the included angle between the center line of the connecting rod of the first arm 22 and the vertical direction is 45°; the zero positions of the pitching joint and the redundant pitching joint can be set according to the mechanical structure and actual requirements, and only one example is given here.

[0052] According to the motion range [P min , P max of the pitching joint and the installation parameters of the surgical arm, the motion range of the surgical arm is calculated. Since it is too late to adjust the working space of the surgical arm when the pitching joint moves to both ends of its motion range, a motion buffer e of the pitching joint is defined, and then the set motion range [P min + e, P max - e] of the pitching joint can be obtained, and the current working space of the surgical arm is calculated accordingly;

[0053] In the present invention, the position of the pitching joint is the pitching angle of the surgical arm. Therefore, the range of the motion buffer e of the pitching joint is [0°, 10°], and the present invention preferably sets e = 10°.

[0054] (2) Adjustment of the working space of the surgical arm;

[0055] Determine the target pose of the end surgical instrument on the surgical arm according to the real-time pose of the end of the main robotic arm, solve the target positions of the joints of the surgical arm through the inverse kinematics of the robotic arm and control the motion of each joint, and obtain the current position of the pitching joint in real time and judge whether it is within the aforementioned set motion range;

[0056] If so, continue to control the motion of each joint of the surgical arm;

[0057] If not, it is necessary to adjust the working space of the surgical arm, that is, to drive the redundant pitching joint movement in the adjustment arm and the synchronous cooperation actions of the remaining joints of the slave manipulator to achieve multi-axis synchronous movement so that the pose of the end surgical instrument on the end of the instrument arm does not change;

[0058] Specifically:

[0059] 1) Calculate the current pose matrix T of the telecentric fixed point through the forward kinematics of the manipulator, and obtain the current positions of the joints of the slave manipulator;

[0060] 2) Judge the movement direction of the redundant pitching joint according to the current position of the pitching joint, and determine the target position of the redundant pitching joint;

[0061] Specifically, if the current position of the pitching joint is within (P max -e, P max , in this embodiment, the counterclockwise rotation direction of the redundant pitching joint is positive, then drive the redundant pitching joint to move in the negative direction, and the movement angle is θ = w * t, where w represents the rotational angular velocity of the redundant pitching joint, and t represents the rotational time step; it is possible to periodically update the movement range of the pitching joint to [P min +θ, P max +θ] every time dt time passes, as Figure 6 shown, so that the current position of the pitching joint falls back into the updated movement range of the pitching joint, and the target position of the redundant pitching joint can be determined; similarly, if the current position of the pitching joint is within [P min , P min +e), then drive the redundant pitching joint to move in the positive direction, and update the movement range of the pitching joint to [P min -θ, P max -θ], as Figure 5 shown;

[0062] 3) Calculate the target positions of the joints of the slave manipulator;

[0063] According to the current pose matrix T of the telecentric fixed point and the target position of the redundant pitching joint, calculate the target positions of the joints of the slave manipulator under the condition of keeping the current pose of the telecentric fixed point unchanged according to the conversion relationship or geometric relationship of each joint, so as to calculate the position increment of the joints of the slave manipulator in combination with 1) and control the execution.

[0064] In another embodiment, determine the target pose of the end surgical instrument on the surgical arm according to the real-time pose of the end of the master manipulator, solve the target positions of the joints of the surgical arm through the inverse kinematics of the manipulator, and calculate and judge whether the target position of the pitching joint is within the aforementioned movement range;

[0065] If so, it indicates that the surgical arm can reach its target pose within its current workspace, and the movements of the joints of the surgical arm are controlled.

[0066] If not, it indicates that the surgical arm cannot reach its target pose within its current workspace. At this time, it is necessary to adjust the workspace of the surgical arm, that is, to drive the redundant pitch joint movement in the adjustment arm and the synchronous cooperation actions of the other joints of the slave manipulator to achieve multi-axis synchronous movement so that the pose of the end surgical instrument does not change.

[0067] Specifically, according to the target position and movement range of the pitch joint, the target position of the redundant pitch joint is calculated, and then the final target positions of the other joints of the slave manipulator are obtained to control the movements of each joint.

[0068] In the present invention, driving the redundant pitch joint movement can calculate its new workspace according to the target pose of the end surgical instrument and its current workspace, and accordingly calculate the angle that the redundant pitch joint should be adjusted; it can also dynamically adjust the workspace of the surgical arm during the operation, set the periodic movement amount of the redundant pitch joint until the workspace of the final surgical arm enables the target pose of the end surgical instrument thereon to be reachable, so as to determine the target position of the redundant pitch joint.

[0069] The present invention can be applied during the surgical operation process, and can also be used in other preoperative or postoperative debugging or maintenance situations.

[0070] The present invention can autonomously judge whether the workspace of the surgical arm needs to be adjusted and make appropriate workspace adjustments, and perform the workspace adjustment of the surgical arm, which can effectively expand the surgical scope without interrupting the operation; and it does not require the bedside nurse to intervene manually for adjustment, nor does it need to re-plan the punching positions on the patient's body surface. Through the autonomous workspace adjustment of the surgical arm, the continuity and smoothness of the operation are ensured, and the overall safety is improved.

[0071] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations (such as quantity, shape, position, etc.) can be made to the technical solution of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A method for adjusting the working space of a surgical arm, characterized in that: Including the steps: Obtain the current workspace of the surgical arm; Determine the target pose of the end surgical instrument according to the real-time pose of the end of the master manipulator; Calculate the target positions of the joints of the surgical arm according to the target pose of the end surgical instrument and control the movement of each joint. Obtain the current position of the pitch joint of the surgical arm in real time and determine whether it is within its set motion range; If so, continue to control the movement of each joint; Otherwise, calculate the current pose matrix of the telecentric fixed point through the forward kinematics of the manipulator, obtain the current positions of the joints of the slave manipulator, judge the movement direction of the redundant pitch joint according to the current position of the pitch joint, and calculate the target position of the redundant pitch joint; If so, control the joints of the surgical arm to move to their target poses; Otherwise, set the periodic motion amount of the redundant pitch joint and periodically update the motion range of the pitch joint so that the current position of the pitch joint falls back into its updated motion range again. Determine the target position of the redundant pitch joint, combine the current pose matrix of the telecentric fixed point with the target position of the redundant pitch joint, drive the redundant pitch joint in the adjustment arm to move to adjust its workspace, and at the same time keep the pose of the end surgical instrument unchanged through the synchronous cooperation actions of the other joints of the slave manipulator.

2. The method for adjusting the working space of the surgical arm according to claim 1, characterized in that: The obtaining of the current workspace of the surgical arm specifically is: Calculate the motion range of the pitch joint of the surgical arm according to the mechanical structure design parameters, so as to obtain the current workspace of the surgical arm.

3. The method for adjusting the working space of the surgical arm according to claim 1, characterized in that: The obtaining of the current workspace of the surgical arm specifically is: Adjust the surgical arm to make the end surgical instrument perform pitch motion around the telecentric fixed point to reach its minimum limit position and maximum limit position, and accordingly obtain the motion range of the pitch joint, and obtain the current workspace of the surgical arm.

4. The method for adjusting the working space of the surgical arm according to claim 3, wherein: The adjusting the surgical arm to make the end surgical instrument perform pitch motion around the telecentric fixed point to reach its minimum limit position and maximum limit position specifically is: Adjust the pitch joint so that the center lines of the connecting rods of the surgical arm coincide to obtain the minimum limit position of the pitch joint; Adjust the pitch joint so that the center lines of the connecting rods of the surgical arm are perpendicular to each other to obtain the maximum limit position of the pitch joint.

5. The method for adjusting the working space of the surgical arm according to claim 2 or 3, characterized in that: Set a motion buffer for the motion range of the pitch joint to obtain the set motion range of the pitch joint, and calculate the current workspace of the surgical arm accordingly.

6. The method for adjusting the working space of the surgical arm according to claim 5, characterized in that: The range of the motion buffer is [0°, 10°].

7. The method for adjusting the working space of the surgical arm according to claim 1, characterized in that: According to the current pose matrix of the telecentric fixed point and the target position of the redundant pitch joint, calculate the target positions of the joints of the slave manipulator when keeping the current pose of the telecentric fixed point unchanged, and calculate the position increments of the joints of the slave manipulator in combination with the current positions of the joints of the slave manipulator, and control and execute.

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