Calibration method and calibration system for surgical tool in surgical robot

Abstract

The application discloses a kind of calibration method and calibration system of surgical tool in surgical robot, by providing calibration block and probe, the calibration block is equipped with blade slot and probe jack, so, probe, calibration block and surgical tool can be installed and connected together and corresponding coordinate relationship is established, at least a first label on the calibration block is identified by camera to obtain the coordinate information to obtain the rotation matrix of surgical tool relative to camera and the coordinate information of second label on the probe is identified to obtain the translation vector of surgical tool in camera space, to obtain the transformation matrix of the surgical tool relative to camera, then the change matrix of the camera relative to the surgical robot is combined, and the transformation matrix of the surgical robot relative to surgical robot end, to obtain the pose relationship of surgical tool and robot end in indirect way, accurate calibration is realized.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to a calibration method and calibration system for surgical instruments in a surgical robot. Background Technology

[0002] The mandible is the bony framework of the lower third of the face and the only facial bone with movement function. Its unique shape forms the basis for individual facial features and normal function. If the shape and function of a patient's mandible are damaged due to disease or accident, resulting in facial deformities and varying degrees of impact on speech, biting, and chewing functions, then mandibular reconstruction treatment is necessary.

[0003] Traditionally, in jaw reconstruction surgery, surgeons manually cut the fibula using surgical instruments such as electric saws. However, electric saws generate significant vibrations during operation, and surgeons are prone to hand tremors. Therefore, relying on manual bone cutting results in instability in precision. Furthermore, the fibula is surrounded by numerous blood vessels, requiring surgeons to maintain prolonged concentration while operating the saw to avoid damaging these vessels. With the development of robotics, robots are increasingly being used, and specialized fibular surgery robots are available. During surgery, surgeons use these robots to perform fibular grafting, overcoming the instability in precision and the inability to maintain sustained physical and mental focus inherent in traditional techniques. This has led to improved surgical outcomes.

[0004] The fibular surgical robot has a surgical blade at its end effector. To accurately control the position and orientation of the surgical blade, the coordinate system of the surgical blade needs to be calibrated. Currently, most robotic tool calibrations use the four-point or seven-point method. Taking the four-point method as an example, in this calibration process, the operator manipulates the surgical blade in four different orientations to align the tip of the blade with a fixed point in space. Using relevant coordinate constraints, the position of the surgical blade in the coordinate system is calibrated. However, this calibration method is not only cumbersome but also has low overall accuracy. In particular, it is limited to surgical blades with point-like ends or surgical blades whose orientation is known. For planar tools such as osteotomy blades, it is much more difficult to simultaneously calibrate the position and orientation of the surgical blade relative to the robot's end effector. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies of the prior art, the present invention discloses a surgical robot to solve the problems of limited calibration orientation, cumbersome operation, and low overall calibration accuracy in the existing related technologies that adopt multi-point calibration methods.

[0006] To achieve the above objectives, this invention discloses a method for calibrating a surgical instrument in a surgical robot, wherein the surgical instrument is located at the end effector of the surgical robot, and the method for calibrating the surgical instrument includes the following steps:

[0007] A calibration block, a probe, and a camera are provided. The calibration block has a blade groove and a probe socket communicating with the blade groove. At least one first label is provided on the calibration surface of the calibration block, and a second label is provided at the first end of the probe. The calibration block is installed and connected to the surgical instrument through the blade groove. The camera is used to identify the coordinate information of the at least one first label on the calibration block to obtain the rotation matrix of the surgical instrument relative to the camera. The probe is inserted into the probe socket of the calibration block, and the camera is used to identify the coordinate information of the second label on the probe to obtain the translation vector of the surgical instrument in the camera space. Based on the rotation matrix of the surgical instrument relative to the camera and the translation vector of the surgical instrument in the camera space, the transformation matrix of the surgical instrument relative to the camera is obtained.

[0008] Obtain the transformation matrix of the surgical robot relative to the surgical robot end effector and the transformation matrix of the camera relative to the surgical robot; and

[0009] The pose relationship between the surgical tool coordinate system and the robot end effector coordinate system is obtained based on the transformation matrix of the surgical tool relative to the camera, the transformation matrix of the camera relative to the surgical robot, and the transformation matrix of the surgical robot relative to the surgical robot end effector.

[0010] In a preferred embodiment of the present invention, the step of mounting and connecting the calibration block to the surgical instrument via the blade groove, and using a camera to identify the coordinate information of at least one first label on the calibration block to obtain the rotation matrix of the surgical instrument relative to the camera, includes the following steps: inserting the surgical instrument into the blade groove of the calibration block, thereby mounting and connecting the calibration block to the surgical instrument, and constructing a surgical instrument coordinate system; wherein, at least one first label on the calibration surface of the calibration block is parallel to the blade surface of the surgical instrument, such that the coordinate system of the at least one first label is consistent with the coordinate system of the surgical instrument; using a camera to identify the at least one first label on the calibration block to obtain the coordinate information of the at least one first label; and obtaining the rotation matrix of the blade surface plane of the surgical instrument relative to the camera based on the coordinate information of the at least one first label.

[0011] In a preferred embodiment of the present invention, constructing the surgical tool coordinate system includes: setting the blade surface of the surgical tool as a plane composed of the X-axis and the Y-axis, setting the direction perpendicular to the blade surface of the surgical tool as the Z-axis, wherein the operating direction of the surgical tool is the X-axis, and the Y-axis is perpendicular to the X-axis; the direction of the probe insertion hole is consistent with the X-axis.

[0012] In a preferred embodiment of the present invention, inserting the probe into the probe socket of the calibration block and using a camera to identify the coordinate information of the second label on the probe to obtain the translation vector of the surgical blade in the camera space includes the following steps: inserting the probe into the probe socket of the calibration block until the second end of the probe contacts the center point of the blade of the surgical blade; using a camera to identify the second label on the first end of the probe and obtain the coordinate information of the second label; and obtaining the translation vector of the center point of the blade of the surgical blade in the camera space based on the coordinate information of the second label, the relationship between the second label and the second end of the probe, and the relationship between the second end of the probe and the center point of the blade.

[0013] In a preferred embodiment of the present invention, the transformation matrix of the camera relative to the surgical robot is obtained by hand-eye calibration; the transformation matrix of the surgical robot relative to the surgical robot end effector is obtained by robot forward calculus.

[0014] This invention discloses a calibration system for surgical instruments in a surgical robot. The surgical instruments are located at the end effector of the surgical robot. The calibration system for the surgical instruments includes:

[0015] A calibration block, wherein the calibration block is provided with a blade groove and a probe insertion hole communicating with the blade groove, the calibration block is installed and connected to the surgical instrument through the blade groove, and at least one first label is provided on the calibration surface of the calibration block;

[0016] A probe, wherein a second label is provided at the first end of the probe, and the second end of the probe is inserted into the probe socket of the calibration block;

[0017] A camera is used to identify the coordinate information of at least one first label on the calibration block to obtain the rotation matrix of the surgical instrument relative to the camera and to identify the coordinate information of the second label to obtain the translation vector of the surgical instrument in the camera space, thereby obtaining the transformation matrix of the surgical instrument relative to the camera.

[0018] In a preferred embodiment of the present invention, after the surgical instrument is inserted into the blade groove of the calibration block, at least one first label on the calibration surface of the calibration block is parallel to the blade surface of the surgical instrument, such that the coordinate system of the at least one first label is consistent with the coordinate system of the surgical instrument.

[0019] In a preferred embodiment of the present invention, in the constructed surgical tool coordinate system, the cutting surface of the surgical tool is set as a plane composed of the X-axis and the Y-axis, and the direction perpendicular to the cutting surface of the surgical tool is set as the Z-axis, wherein the operating direction of the surgical tool is the X-axis, and the Y-axis is perpendicular to the X-axis; the direction of the probe insertion hole is consistent with the X-axis.

[0020] In a preferred embodiment of the present invention, after the second end of the probe is inserted into the probe socket of the calibration block, the second end of the probe contacts the center point of the blade of the surgical instrument.

[0021] This invention discloses a surgical blade auxiliary calibration device, which cooperates with a camera to perform the aforementioned surgical blade calibration method. The surgical blade auxiliary calibration device includes:

[0022] A calibration block, wherein the calibration block has a blade groove and a probe insertion hole communicating with the blade groove, the calibration block is installed and connected to the surgical instrument through the blade groove, and at least one first label is provided on the calibration surface of the calibration block; and

[0023] The probe has a second label at its first end and is inserted into the probe socket of the calibration block at its second end.

[0024] This invention discloses a calibration method and system for surgical instruments in a surgical robot. Compared with the prior art, the calibration method and system for surgical instruments in a surgical robot of this invention have at least the following technical effects: By providing a calibration block and a probe, the calibration block having a blade groove and a probe insertion hole, the probe, calibration block, and surgical instrument can be installed and connected together to establish a corresponding coordinate relationship. Thus, on the one hand, the coordinate information of at least one first label on the calibration block is used to identify the rotation matrix of the surgical instrument relative to the camera by the camera; on the other hand, the coordinate information of the second label on the probe is used to identify the translation vector of the surgical instrument in the camera space, thereby obtaining the transformation matrix of the surgical instrument relative to the camera. Combined with the transformation matrix of the camera relative to the surgical robot and the transformation matrix of the surgical robot relative to the end effector of the surgical robot, the pose relationship between the surgical instrument and the end effector of the robot is obtained indirectly, achieving accurate calibration.

[0025] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0026] Figure 1 The diagram shows an application of the calibration system for surgical tools in the surgical robot of the present invention in one embodiment.

[0027] Figure 2 Displayed as Figure 1 A schematic diagram of the calibration block and probe in the calibration system for surgical instruments, combined with the surgical instrument.

[0028] Figure 3 The diagram shown is a flowchart illustrating the calibration method for surgical instruments in the surgical robot of the present invention in one embodiment. Detailed Implementation

[0029] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the information disclosed herein. This disclosure can also be implemented or applied through other different specific embodiments, and various details in this disclosure can be modified or changed according to different viewpoints and application modules without departing from the spirit of this disclosure. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be combined with each other.

[0030] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings, so that those skilled in the art to which this disclosure pertains can readily implement it. This disclosure may be embodied in many different forms and is not limited to the embodiments described herein.

[0031] In the representation of this disclosure, the terms “first” and “second” are used for illustrative purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. While in some examples the terms first, second, etc., are used herein to denote various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, “first interface” and “second interface”, etc., are used. Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms “comprising” and “including” indicate the presence of the stated feature, step, operation, element, module, item, type, and / or group, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, modules, items, types, and / or groups. The terms “or” and “and / or” as used herein are to be construed as inclusive, or mean any one or any combination thereof. Therefore, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C". Exceptions to this definition will only occur if the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0032] In existing fibular graft surgeries, the traditional method involves the surgeon manually cutting the fibula with a handheld electric saw. This method suffers from problems such as insufficient stability, poor cutting precision, and significant susceptibility to human error, placing considerable stress on the surgeon. To address this, the inventors have designed a fibular surgical robot for mandibular reconstruction. This robot mounts surgical instruments onto a six-degree-of-freedom robotic arm connected in a series and parallel configuration, combining the characteristics of both parallel and series operations. This results in advantages such as zero cumulative error, high precision, high speed, and a large range of motion. Thus, using this fibular surgical robot allows the surgeon to collaborate with the surgeon during mandibular reconstruction surgery to complete the fibular cutting. This improves osteotomy precision, enhances postoperative healing of the reconstructed fibula, and significantly reduces the surgeon's workload.

[0033] The end effector of the fibular surgical robot is equipped with a surgical blade. To accurately control the position and orientation of the surgical blade, the coordinate system of the surgical blade needs to be calibrated. However, existing traditional multi-point calibration methods are not only cumbersome to operate but also have low overall calibration accuracy. In particular, they are limited to surgical blades with point-like ends or surgical blades with known orientations. For planar tools such as osteotomy blades, it is much more difficult to simultaneously calibrate the position and orientation of the surgical blade relative to the robot's end effector.

[0034] In view of this, the present invention discloses a calibration method and calibration system for surgical instruments in a surgical robot, which can achieve accurate calibration in a relatively simple way.

[0035] It should be noted that in the following description, the present invention is illustrated using the aforementioned fibular surgical robot as an example, but it is not limited thereto. Those skilled in the art will understand that the present invention can also be adapted for the calibration of other surgical robots or even general-purpose robots, and should have the same or similar effects.

[0036] Please see Figure 1 The diagram shows an application schematic of the surgical instrument calibration system in the surgical robot of the present invention in one embodiment. The surgical robot to which the surgical instrument calibration system of the surgical robot of the present invention is applied may be, for example, a fibular surgical robot, used to perform fibular osteotomy on a patient.

[0037] like Figure 1As shown, the surgical robot comprises a robot base 21, a three-degree-of-freedom Delta parallel mechanism 22, a three-degree-of-freedom serial mechanism 23, a robot end effector 24, and a surgical instrument 25. The three-degree-of-freedom Delta parallel mechanism 22 and the three-degree-of-freedom serial mechanism 3, combined, can construct a six-degree-of-freedom hybrid robotic arm, thereby giving the surgical instrument 25, mounted thereon, a high degree of flexibility. In some embodiments, the robot end effector 24 may be equipped with an end effector, and the surgical instrument 25 may be mounted on the end effector. Alternatively, in some embodiments, the surgical instrument 25 may be directly mounted on the robot end effector 24.

[0038] When the application Figure 1 When performing fibular transplantation surgery using the fibular surgical robot, the osteotomy path is first imported into the fibular surgical robot. The fibular surgical robot then adjusts the posture of the surgical blade 25 according to the imported osteotomy path. The surgeon then operates the surgical blade 25 to the vicinity of the cutting starting point and performs the osteotomy.

[0039] In order to accurately control the position and orientation of the surgical instrument, it is necessary to calibrate the coordinate system of the surgical instrument. For example, it is necessary to obtain the pose relationship between the surgical instrument 25 and the robot end effector 24.

[0040] The surgical tool calibration system provided by the present invention includes a calibration block 11, a probe 13, and a camera 15. The surgical tool calibration system can be used to obtain the transformation matrix of the surgical tool 25 relative to the camera 15, and then obtain the pose relationship between the surgical tool 25 and the robot end effector 24.

[0041] To obtain the pose relationship between the surgical instrument 25 and the robot end effector 24 (i.e. Figure 1 The relationship Y in the equation is traditionally obtained directly using multi-point calibration methods (e.g., four-point, six-point, or seven-point methods). Taking the four-point method as an example, in this calibration process, the operator manipulates the surgical instrument in four different postures to align the tip of the instrument with a fixed point in space. The position of the surgical instrument in the coordinate system is then calibrated using relevant coordinate constraints. However, this calibration method is not only cumbersome but also has low overall accuracy. In particular, it is limited to surgical instruments with point-like ends or those whose posture is known. For planar tools like osteotomy blades, calibrating both the position and posture of the surgical instrument relative to the robot's end effector simultaneously is significantly more difficult.

[0042] In this invention, by providing a calibration system for the surgical instrument, the attitude relationship between the surgical instrument 25 and the camera 15 is obtained. Figure 1 The relationship between camera 15 and surgical robot (i.e., robot base 21) is obtained through other known methods (relationship A in the diagram), and the attitude relationship between camera 15 and surgical robot (i.e., robot base 21) is obtained through other known methods. Figure 1 The relationship X in the equation, and the transformation matrix between the surgical robot (i.e., the robot base 21) and the surgical robot end effector 24. Figure 1 Relationship B) is used to indirectly obtain the pose relationship between the surgical instrument 25 and the robot end effector 24 through calculation. That is, assuming the pose relationship between the surgical instrument and the robot end effector is expressed as: Based on the matrix relationships of the system:

[0043]

[0044] The orientation relationship between the surgical blade 25 and the camera 15 can be obtained through the calibration system of the surgical blade of the present invention.

[0045] Please see Figure 2 Displayed as Figure 1 A planar schematic diagram showing the combination of calibration block 11 and probe 13 with surgical blade 25 in the calibration system of surgical blade.

[0046] The following combination Figure 1 and Figure 2 The calibration system for the surgical instruments of the present invention will be described in detail.

[0047] The calibration block 11 has a block structure; in some embodiments, the calibration block 11 is a cube.

[0048] The calibration block 11 is provided with a blade slot (not shown in the figure) and a probe socket (not shown in the figure) communicating with the blade slot.

[0049] The blade groove is adapted to the surgical instrument 25 for insertion therein. In this invention, the surgical instrument 25 in the surgical robot is a planar tool, having at least a flat blade surface 251 and a cutting edge 253 located at the front end of the blade surface 251. The cutting edge is serrated. By pushing the surgical instrument 25 back and forth, the serrated cutting edge 253 in the surgical instrument 25 can reciprocate to contact the surgical object (e.g., the fibula or related tissue) and perform osteotomy. In some embodiments, the serrated cutting edge 253 may also be designed with a certain bevel, for example, an upper bevel, a lower bevel, or both bevels.

[0050] The surgical blade 25 may have a blade mounting structure at its rear end, allowing it to be directly mounted to the robot end effector 24 via the blade mounting structure or via an end effector. Thus, the calibration block 11 can be inserted into the surgical blade 25 through its blade slot and then connected to it; that is, the calibration block 11 is mounted to the robot end effector 24 via its blade slot.

[0051] In this invention, the blade 251 of the surgical tool 25 is a planar tool, and correspondingly, the groove surface of the blade groove is a planar structure. The groove plane of the blade groove is parallel to the calibration surface in the calibration block 11 (a certain surface in the calibration block 11 can be set as the calibration surface). Therefore, when the calibration block 11 inserts the surgical tool 25 through the blade groove and is installed and connected to the surgical tool 25, the blade 251 of the surgical tool 25 is parallel and consistent with the calibration surface of the calibration block 11.

[0052] In this invention, we can construct a corresponding surgical tool coordinate system based on the structural characteristics of the surgical tool 25: the blade surface of the surgical tool mounted on the robot end effector is set as a plane composed of the X-axis and Y-axis, and the direction perpendicular to the blade surface of the surgical tool is set as the Z-axis. The operating direction of the surgical tool 25 is the X-axis, and the direction perpendicular to the X-axis is the Y-axis. For ease of calculation, as... Figure 2 As shown, the center point of the blade of the surgical instrument 25 is set as the origin of the surgical instrument coordinate system.

[0053] At least one first label is provided on the calibration surface of the surgical instrument. For example... Figure 2 As shown, a first label 12 is provided at each of the three corners of the calibration surface 111 of the calibration block 11. However, this is not a limitation. In some embodiments, a first label is provided at one corner of the calibration surface of the surgical instrument, or at each of two corners of the calibration surface of the surgical instrument (these two corners may be on the same side or diagonally opposite), or at all four corners of the calibration surface of the surgical instrument. The first label 12 is a square reference mark of a QR code generated by a visual reference system such as ArUco or April Tag. The main advantage of this type of square reference mark of a QR code is that a single mark can provide sufficient correspondence (four corners) to obtain the camera pose, and the internal binary encoding matrix can be used for misalignment detection and correction.

[0054] like Figure 2 As shown, the first label 12 is an ArUco label. ArUco labels are a type of label proposed by Rafael and Sergio Garrido. The four corner points of an ArUco label form four control points, surrounded by a black border. This black border facilitates rapid detection in an image. The internal structure is a binary encoding matrix for misalignment detection and correction. ArUco labels can be obtained using OpenCV. In general applications, they can be printed onto paper using a regular printer. For higher precision applications, the resolution of the label image can be increased, and a more precise printing method can be used to obtain the label. Of course, in other embodiments, the calibration label can also be a custom-designed label.

[0055] After the calibration block 11 inserts the surgical instrument 25 through the blade slot and is connected to the surgical instrument 25, the first label plane of at least one first label 12 on the calibration surface 111 of the calibration block 11 is parallel to the blade surface 251 of the surgical instrument 25 (i.e., the plane formed by the X-axis and Y-axis in the surgical instrument coordinate system). Thus, the camera can identify at least one first label 12 on the calibration block 11, obtain the coordinate information of the at least one first label 12, and, based on the coordinate information of the at least one first label 12, obtain the rotation matrix of the blade surface plane of the surgical instrument 25 relative to the camera 15.

[0056] The calibration block 11 has a probe socket that communicates with the blade slot and allows the probe 13 to be inserted. In this embodiment, the probe 13 is a straight rod type; therefore, the probe socket is a straight hole. Through the probe socket, one end of the probe 13 can be inserted into the probe socket and connected to the calibration block 11.

[0057] The probe 13 has a second tag 14 at its first end. In some embodiments, the first end of the probe 13 may correspond to or be specifically associated with the center of the second tag 14. The second tag 14 is a square reference mark of a QR code generated by a visual reference system such as ArUco or AprilTag. The main advantage of this type of square reference mark of a QR code is that a single mark can provide sufficient correspondence (four corners) to obtain the camera pose, and the internal binary encoding matrix can be used for misalignment detection and correction. Figure 2 As shown, the second label 14 is an ArUco label. The four corner points of the ArUco label constitute four control points, surrounded by a black border. This black border facilitates rapid detection in the image. The interior contains a binary encoding matrix for misalignment detection and correction. Of course, in other embodiments, the calibration label can also be a custom-designed label.

[0058] When the second end (also called the insertion end) of the probe 13 is inserted into the probe socket of the calibration block 11 until the second end of the probe 13 contacts the center point of the blade 253 of the surgical instrument 25, the second end point of the probe 13 is located at the origin of the surgical instrument coordinate system, and the extension direction of the probe is located on the X-axis of the surgical instrument coordinate system. The second label plane of the second label 14 on the first end of the probe 13 is parallel to the first label plane of at least one first label 12 on the calibration block 11 (i.e., the plane formed by the X-axis and Y-axis in the surgical instrument coordinate system). Thus, the camera identifies the second label 14 on the first end of the probe 13, obtains the coordinate information of the second label, and, based on the coordinate information of the second label, the relationship between the second label and the second end of the probe, and the relationship between the second end of the probe and the center point of the blade, obtains the translation vector of the center point of the blade in the camera space.

[0059] Thus, in this invention, based on the aforementioned rotation matrix of the surgical instrument 25 relative to the camera 15... and the translation vector of the surgical instrument 25 in camera space The transformation matrix of the surgical instrument 25 relative to the camera 15 is obtained.

[0060] Subsequently, the transformation matrix of the surgical instrument relative to the camera can be used to... The change matrix of the camera relative to the surgical robot and the transformation matrix of the surgical robot relative to the surgical robot end effector Based on the aforementioned formula (1), the pose relationship between the surgical instrument and the robot end effector is finally obtained.

[0061] The change matrix of the camera relative to the surgical robot It was obtained through hand-eye calibration. Hand-eye calibration is a conventional technique in this field, so it will not be described in detail here.

[0062] The transformation matrix of the surgical robot relative to the surgical robot end effector It was obtained through forward kinematics. Forward kinematics refers to calculating the position and pose of a robot's end effector given the motion parameters and angles of each joint. Forward kinematics is a standard technique in this field and will not be elaborated upon here.

[0063] In addition, similar to the calibration system for surgical blades in the surgical robot, the present invention also discloses a surgical blade auxiliary calibration device, which includes a calibration block and a probe.

[0064] The calibration block has a blade groove and a probe insertion hole communicating with the blade groove. The calibration block is installed and connected to the surgical instrument through the blade groove. At least one first label is affixed to the calibration surface of the calibration block. For details on the structure and function of the calibration block and the characteristics of the first label, please refer to the previous description, which will not be repeated here.

[0065] The probe has a second tag at its first end, and the second end of the probe is inserted into the probe socket of the calibration block. For details regarding the structure and function of the probe, as well as the characteristics of the second tag, please refer to the preceding description; further details will not be repeated here.

[0066] Based on the aforementioned calibration system for surgical instruments in a surgical robot, calibration operations can be performed using this system. Therefore, this invention also discloses a calibration method applied to the aforementioned calibration system for surgical instruments.

[0067] Please see Figure 3 The diagram shows a flowchart of a method for calibrating surgical instruments in the surgical robot of the present invention in one embodiment.

[0068] like Figure 3 As shown, the calibration method for the surgical instrument includes the following steps:

[0069] Step S301: Install and connect the calibration block to the surgical instrument, and use a camera to identify the coordinate information of at least one first label on the calibration block to obtain the rotation matrix of the surgical instrument relative to the camera.

[0070] In this invention, the calibration block 11 is a block structure, and in some embodiments, the calibration block 11 is a cube.

[0071] The calibration block 11 is provided with a blade groove and a probe insertion hole communicating with the blade groove, and at least one first label 12 is provided on the calibration surface 111 of the calibration block 11.

[0072] The blade groove is adapted to the surgical tool 25 for insertion. In this invention, the surgical tool 25 in the surgical robot is a planar tool, having at least a flat blade surface 251 and a cutting edge 253 located at the front end of the blade surface 251, the cutting edge being a serrated edge. The calibration block 11 can be inserted into the surgical tool 25 through the blade groove and then connected to it; that is, the calibration block 11 is mounted to the robot end effector 24 through the blade groove.

[0073] The blade 251 of the surgical instrument 25 is a planar tool. Correspondingly, the groove surface of the blade groove is a planar structure. The groove plane of the blade groove is parallel to the calibration surface in the calibration block 11 (a certain surface in the calibration block 11 can be set as the calibration surface). Therefore, when the calibration block 11 inserts the surgical instrument 25 through the blade groove and is installed and connected to the surgical instrument 25, the blade 251 of the surgical instrument 25 is parallel and consistent with the calibration surface of the calibration block 11.

[0074] In this invention, we can construct a corresponding surgical tool coordinate system based on the structural characteristics of the surgical tool 25: the blade surface of the surgical tool mounted on the robot end effector is set as a plane composed of the X-axis and Y-axis, and the direction perpendicular to the blade surface of the surgical tool is set as the Z-axis. The operating direction of the surgical tool 25 is the X-axis, and the direction perpendicular to the X-axis is the Y-axis. For ease of calculation, as... Figure 2 As shown, the center point of the blade of the surgical instrument 25 is set as the origin of the surgical instrument coordinate system.

[0075] At least one first label is provided on the calibration surface of the surgical instrument. For example... Figure 2 As shown, a first label 12 is provided at each of the three corners of the calibration surface 111 of the surgical instrument 25. However, this is not a limitation on the danger. In some embodiments, a first label is provided at one corner of the calibration surface of the surgical instrument, or at each of two corners of the calibration surface of the surgical instrument (these two corners may be on the same side or diagonally opposite), or at all four corners of the calibration surface of the surgical instrument. The first label 12 is a square reference mark of a QR code generated by a visual reference system such as ArUco or April Tag.

[0076] After the calibration block 11 inserts the surgical instrument 25 through the blade slot and is connected to the surgical instrument 25, the first label plane of at least one first label 12 on the calibration surface 111 of the calibration block 11 is parallel to the blade surface 251 of the surgical instrument 25 (i.e., the plane formed by the X-axis and Y-axis in the surgical instrument coordinate system). Thus, the camera can identify at least one first label 12 on the calibration block 11, obtain the coordinate information of the at least one first label 12, and, based on the coordinate information of the at least one first label 12, obtain the rotation matrix of the blade surface plane of the surgical instrument 25 relative to the camera 15.

[0077] Step S303: Install the probe on the calibration block and the surgical instrument, and use the camera to identify the coordinate information of the second label on the calibration block to obtain the translation vector of the surgical instrument in the camera space.

[0078] In this invention, the calibration block 11 has a probe socket that communicates with the blade slot and allows the probe 13 to be inserted. In this embodiment, the probe 13 is a straight rod type; therefore, the probe socket is a straight hole. Through the probe socket, one end of the probe 13 can be inserted into the probe socket and connected to the calibration block 11.

[0079] The probe 13 has a second tag 14 at its first end. In some embodiments, the first end of the probe 13 may correspond to or be specifically associated with the center of the second tag 14. The second tag 14 is a square reference mark of a QR code generated by a visual reference system such as ArUco or AprilTag. The main advantage of this type of square reference mark of a QR code is that a single mark can provide sufficient correspondence (four corners) to obtain the camera pose, and the internal binary encoding matrix can be used for misalignment detection and correction.

[0080] When the second end (also called the insertion end) of the probe 13 is inserted into the probe socket of the calibration block 11 until the second end of the probe 13 contacts the center point of the blade 253 of the surgical instrument 25, the second end point of the probe 13 is located at the origin of the surgical instrument coordinate system, and the extension direction of the probe is located on the X-axis of the surgical instrument coordinate system. The second label plane of the second label 14 on the first end of the probe 13 is parallel to the first label plane of at least one first label 12 on the calibration block 11 (i.e., the plane formed by the X-axis and Y-axis in the surgical instrument coordinate system). Thus, the camera identifies the second label 14 on the first end of the probe 13, obtains the coordinate information of the second label, and, based on the coordinate information of the second label, the relationship between the second label and the second end of the probe, and the relationship between the second end of the probe and the center point of the blade, obtains the translation vector of the center point of the blade in the camera space.

[0081] Step S305: Based on the rotation matrix of the surgical instrument relative to the camera and the translation vector of the surgical instrument in the camera space, obtain the transformation matrix of the surgical instrument relative to the camera.

[0082] In this invention, the rotation matrix of the surgical instrument 25 relative to the camera 15 is used. and the translation vector of the surgical instrument 25 in camera space The transformation matrix of the surgical instrument 25 relative to the camera 15 is obtained.

[0083] As can be seen from steps S301 to S305, by using the provided calibration block with a first label, the probe with a second label, and the camera, the rotation matrix of the surgical instrument relative to the camera can be obtained by using the camera to identify the first label on the calibration block. Furthermore, by using a camera to identify the second tag on the probe, the translation vector of the surgical instrument in the camera space can be obtained. Therefore, the transformation matrix of the surgical instrument relative to the camera is obtained.

[0084] Subsequently, the calibration method for the surgical tools may further include the following steps:

[0085] Step S307: Obtain the transformation matrix of the surgical robot relative to the surgical robot end effector and the transformation matrix of the camera relative to the surgical robot.

[0086] In some embodiments, the transformation matrix of the surgical robot relative to the surgical robot end effector The transformation matrix of the camera relative to the surgical robot can be obtained through the robot forward solving method. It can be obtained through hand-eye calibration.

[0087] Step S309: Based on the transformation matrix of the surgical instrument relative to the camera, the transformation matrix of the camera relative to the surgical robot, and the transformation matrix of the surgical robot relative to the surgical robot end effector, the pose relationship between the surgical instrument and the robot end effector is obtained.

[0088] In some embodiments, based on the transformation matrix of the surgical instrument relative to the camera The change matrix of the camera relative to the surgical robot and the transformation matrix of the surgical robot relative to the surgical robot end effector Based on the aforementioned formula (1), the pose relationship between the surgical instrument and the robot end effector is finally obtained.

[0089] The calibration method and system for surgical instruments in a surgical robot disclosed in this invention have at least the following technical effects: By providing a calibration block and a probe, wherein the calibration block is provided with a blade groove and a probe insertion hole, the probe, calibration block, and surgical instrument can be installed and connected together to establish a corresponding coordinate relationship. Thus, on the one hand, the coordinate information of at least one first label on the calibration block is used to identify the rotation matrix of the surgical instrument relative to the camera by the camera, and on the other hand, the coordinate information of the second label on the probe is used to identify the translation vector of the surgical instrument in the camera space, thereby obtaining the transformation matrix of the surgical instrument relative to the camera. By combining the transformation matrix of the camera relative to the surgical robot and the transformation matrix of the surgical robot relative to the end effector of the surgical robot, the pose relationship between the surgical instrument and the end effector of the robot is obtained indirectly, thereby achieving accurate calibration.

[0090] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for calibrating surgical instruments in a surgical robot, characterized in that, The surgical instrument is located at the end of the surgical robot, and the calibration method for the surgical instrument includes the following steps: A calibration block, a probe, and a camera are provided. The calibration block has a blade groove and a probe socket communicating with the blade groove. At least one first label is provided on the calibration surface of the calibration block, and a second label is provided at the first end of the probe. The surgical instrument is inserted into the blade slot of the calibration block, thereby connecting the calibration block and the surgical instrument to establish a surgical instrument coordinate system. At least one first label on the calibration surface of the calibration block is parallel to the blade surface of the surgical instrument, such that the coordinate system of the at least one first label is consistent with the surgical instrument coordinate system. A camera is used to identify the at least one first label on the calibration block, obtaining the coordinate information of the at least one first label. Based on the coordinate information of the at least one first label, the rotation matrix of the blade surface plane of the surgical instrument relative to the camera is obtained. The probe is inserted into the probe socket of the calibration block, and the camera is used to identify the coordinate information of the second label on the probe to obtain the translation vector of the surgical instrument in the camera space; The transformation matrix of the surgical instrument relative to the camera is obtained based on the rotation matrix of the surgical instrument relative to the camera and the translation vector of the surgical instrument in the camera space. Obtain the transformation matrix of the robot base relative to the surgical robot end effector and the transformation matrix of the camera relative to the robot base; and The pose relationship between the surgical instrument and the robot end effector is obtained based on the transformation matrix of the surgical instrument relative to the camera, the transformation matrix of the camera relative to the robot base, and the transformation matrix of the robot base relative to the surgical robot end effector.

2. The method for calibrating surgical instruments in a surgical robot according to claim 1, characterized in that, The surgical tool coordinate system includes: setting the blade surface of the surgical tool as a plane composed of the X-axis and the Y-axis, setting the direction perpendicular to the blade surface of the surgical tool as the Z-axis, wherein the operating direction of the surgical tool is the X-axis, and the Y-axis is perpendicular to the X-axis; the direction of the probe insertion hole is consistent with the X-axis.

3. The method for calibrating surgical instruments in a surgical robot according to claim 1, characterized in that, The step of inserting the probe into the probe socket of the calibration block and using a camera to identify the coordinate information of the second label on the probe to obtain the translation vector of the surgical instrument in the camera space includes the following steps: Insert the probe into the probe socket of the calibration block until the second end of the probe contacts the center point of the blade of the surgical instrument; The camera is used to identify the second tag on the first end of the probe, and the coordinate information of the second tag is obtained; as well as Based on the coordinate information of the second label, the relationship between the second label and the second end of the probe, and the relationship between the second end of the probe and the center point of the blade, the translation vector of the center point of the surgical blade in the camera space is obtained.

4. The method for calibrating surgical instruments in a surgical robot according to claim 1, characterized in that, The transformation matrix of the camera relative to the robot base is obtained through hand-eye calibration; the transformation matrix of the robot base relative to the surgical robot end effector is obtained through robot forward calculus.

5. A surgical instrument auxiliary calibration device, characterized in that, The surgical blade calibration aid device works in conjunction with a camera to perform the surgical blade calibration method as described in any one of claims 1 to 4, wherein the surgical blade calibration aid device comprises: A calibration block, wherein the calibration block has a blade groove and a probe insertion hole communicating with the blade groove, the calibration block is installed and connected to the surgical instrument through the blade groove, and at least one first label is provided on the calibration surface of the calibration block; and The probe has a second label at its first end and is inserted into the probe socket of the calibration block at its second end.

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