WO2024027857A1

WO2024027857A1 - Method and system for registration of surgical robot coordinate system with ct scanner coordinate system

Info

Publication number: WO2024027857A1
Application number: PCT/CN2023/125927
Authority: WO
Inventors: 甘承军; 隋晨光; 郭岩中
Original assignee: 苏州派尼迩医疗科技有限公司
Priority date: 2023-04-07
Filing date: 2023-10-23
Publication date: 2024-02-08
Also published as: CN116392246A; CN117835933A

Abstract

A method and system for the registration of a surgical robot coordinate system with a CT scanner coordinate system. The system comprises a 3D structured light camera (1) and a calibration plate (2), which are used cooperatively with a surgical robot console, a robotic arm (4), and a CT scanner, wherein a 3D visual system is used for the registration of the CT scanner coordinate system with a robotic arm coordinate system of the surgical robot; and the 3D structured light camera (1) in the 3D visual system moves synchronously with the robotic arm (4) and a puncture device (3) fixedly mounted at the end of the robotic arm (4). In this way, a coordinate registration process in a robot surgical procedure is simplified. The 3D structured light camera (1) and the puncture device (3) are both mounted at the end of the robotic arm (4), so that the surgical robot has a reduced size.

Description

Method and system for registering surgical robot coordinate system and CT machine coordinate system

Technical field

The present invention relates to the field of puncture robots, and specifically to a method and system for registering the coordinate system of a surgical robot and the coordinate system of a CT machine.

Background technique

In the process of using a robot to perform puncture surgery, the doctor will diagnose the patient and formulate a surgical plan based on medical imaging equipment (such as a CT machine), and then the surgical robot will perform the puncture surgery based on the surgical plan given by the doctor. Only after the coordinate system of the surgical robot is aligned with the coordinate system of the medical imaging equipment can the surgical robot complete the surgical action according to the surgical plan formulated by the doctor.

At present, most surgical robots use infrared binocular cameras to take pictures of the sign components fixed on the robotic arm and the sign components fixed on the human body. Then, combined with the CT images of the sign components fixed on the human body, through the pattern recognition algorithm and spatial geometry, Algorithm to determine the coordinate registration of the robotic arm and CT machine. This technology and method requires the fixed installation of marker components on both the patient and the robotic arm, and a large infrared binocular camera placed outside the robotic arm at a suitable position with a view. The entire system is complex and inconvenient to operate, requiring medical staff to The operation can only be completed after a long training period. In particular, fixing the landmark component on the patient requires the patient's effective cooperation, which limits the widespread promotion and application of surgical robots.

Contents of the invention

The purpose of the present invention is to provide a method for registering the coordinate system of a surgical robot and the coordinate system of a CT machine. It is a completely new registration method. The present invention only requires a high-precision, small-sized robot to be fixedly installed at the end of the robotic arm. The 3D structured light camera, combined with the calibration plate specially designed according to the 3D structured light camera of the present invention, can complete the registration of the robot arm coordinates and the CT machine coordinates by placing the calibration plate on the CT machine, without the need to fix the corresponding coordinates on the robot arm and the patient. It also eliminates the need for additional large-scale infrared binocular cameras, making the surgical robot equipment simpler and easier to use and operate. It can be widely promoted and applied and is suitable for medical units of all levels.

The method for registering the coordinate system of the surgical robot and the coordinate system of the CT machine in the present invention uses a 3D vision system to register the coordinate system of the CT machine and the coordinate system of the mechanical arm in the surgical robot. The 3D structured light in the 3D vision system The camera moves synchronously with the robotic arm and the puncture device fixedly installed at the end of the robotic arm.

Preferably, the 3D vision system includes a 3D structured light camera installed at the end of the robotic arm and fixed as a whole with the puncture device. It can be directly placed on the CT machine and is located where the 3D structured light camera takes pictures. Calibration board within range.

Preferably, it is used to register the CT machine coordinate system and the robot arm coordinate system, which is characterized in that the following steps are performed:

1) Move the robotic arm fixed with the 3D structured light camera to the surgical area next to the CT machine;

2) Place the calibration plate on the CT machine and within the range that can be photographed by the 3D structured light camera;

3) Start the registration process. The robotic arm carries the 3D structured light camera and moves to multiple poses in sequence. After moving to each pose, the 3D structured light camera is turned on to project multiple sets of structured light and collect the structured light. Project the photos of the calibration structure in the calibration plate, record the transformation parameters of the robot arm in each posture and the photos of the calibration structure in the calibration plate through computer software, and use the hand-eye calibration algorithm to obtain the coordinate system of the calibration plate. The transformation relationship with the robot arm coordinate system is the third transformation matrix;

4) The robotic arm is retracted to the initial position, the calibration plate continues to be placed on the CT machine and remains motionless, and the CT machine is started to scan the calibration plate; CT scans of the four spherical calibration parts on the calibration plate are obtained. The image data is combined with the coordinate matrix of the spherical center of the four spherical calibration parts against the calibration plate to obtain the conversion relationship between the CT coordinate system and the calibration plate coordinate system, which is the fourth conversion matrix;

5) Obtain the CT machine coordinate system based on the third transformation matrix between the calibration plate coordinate system and the robot arm coordinate system and the fourth transformation matrix between the CT machine coordinate system and the calibration plate coordinate system. The conversion relationship with the robot arm coordinate system is the fifth transformation matrix, which completes the coordinate registration between the CT machine coordinate system and the robot arm coordinate system.

Preferably, in step 3), the following steps are performed:

3.1) Start the registration procedure. The robotic arm carries the 3D structured light camera and moves to n different preset poses in sequence. After moving to each pose, the calibration plate in each pose is acquired. The conversion relationship between the coordinate system and the camera coordinate system is the first conversion matrix W _BC ; the conversion relationship between the end center point of the robotic arm and the robotic arm coordinate system is the second conversion matrix W _AT ;

3.2) Select the first transformation matrix W _BC and the second transformation matrix W _AT corresponding to two of the poses (i, j), and obtain the camera coordinate system and the robot end center point coordinate system according to the following equation (1) The transformation matrix W _CT ^(ij) ;
W _AT ⁽ⁱ⁾ W _CT ^(ij) W _BC ⁽ⁱ⁾ = W _AT ^(j) W _CT ^(ij) W _BC ^(j) (1)

3.3) Obtain the transformation matrix W _AB ^{(ij) of the calibration plate coordinate system and the robot arm coordinate system for the two poses (i, j) according to the following equation (2)} ;
W _AB ^(ij) = W _AT ⁽ⁱ⁾ W _CT ^(ij) W _BC ⁽ⁱ⁾ = W _AT ^(j) W _CT ^(ij) W _BC ^(j) (2)

3.4) Repeat steps 3.2) and 3.3) to select the first transformation matrix W _BC and the second transformation matrix W _AT of two different postures from n postures. After combination, n*(n-1)/2 can be obtained the conversion matrices W _AB ^(ij) ; calculate the average value for the same variables corresponding to the n*(n-1)/2 conversion matrices W _AB ^(ij) , and combine the average values of all the same variables into The conversion relationship between the calibration plate coordinate system and the robot arm coordinate system is called the third conversion matrix

Preferably, in step 3.1), the following steps are performed after the robotic arm moves to each posture:

3.1.1) The 3D structured light camera projects structured light to the calibration plate, collects photos of the mark structure in the calibration plate projected by the structured light, and records the posture transformation parameters of the robotic arm and the structured light by computer software The photo of the landmark structure in the calibration plate is projected onto the camera, and the conversion relationship between the coordinate system of the calibration plate and the center point coordinate system of the 3D structured light camera for this pose is obtained through the hand-eye calibration algorithm, which is the first conversion. matrix W _BC ;

3.1.2) Based on the pose transformation parameters of the robot arm in each pose, obtain the pose representation of the center point of the robot arm in the robot arm coordinate system, that is, the coordinate system of the center point of the robot arm end and the coordinates of the robot arm in this pose The conversion relationship between systems is the second conversion matrix W _AT .

Preferably, the number of poses that the 3D structured light camera moves with the robotic arm in step 3) is 4-25.

Preferably, the 3D structured light camera in step 3.1.1) projects blue-violet LED light with a wavelength of 490 nm to the calibration plate in the form of a 13-24 stripe grating.

Preferably, the calibration plate includes a base plate, four spherical calibration members, a cylindrical connector for fixedly connecting the base plate and the spherical calibration member, and a lock for locking the cylindrical connector and the base plate. Firmware, the height of each columnar connector is distributed in equal rows, all columnar connectors are fixedly arranged on the same side surface of the base plate, and the substrate is provided with a checkerboard pattern on the side surface where the columnar connectors are provided. .

Preferably, the cylindrical connector includes a first connection portion connected to the spherical calibration member and a second connection portion connected to the base plate, and the first connection portion is provided with a hole for the spherical calibration member to sink into. A cylindrical groove, the depth of the groove is greater than the radius of the spherical calibration piece, and the inner diameter of the groove is less than or equal to the diameter of the spherical calibration piece.

In the present invention, there is a system for registering the coordinate system of the surgical robot and the coordinate system of the CT machine, a 3D structured light camera and a calibration plate used in conjunction with the surgical robot console, robotic arm, and CT machine. The 3D structured light camera and the The puncture device installed at the end of the robotic arm is fixedly installed together, and moves together with the puncture device as the robotic arm moves.

When using the system of the present invention for registration, you only need to push the surgical robot and robotic arm equipped with a 3D structured light camera to the side of the CT machine, place the calibration plate within the range of the CT machine tool that can be photographed by the 3D structured light camera, and start the program. Then the coordinate registration can be automatically completed, which is simple to operate, easy to learn and use. This greatly simplifies the operation difficulty of the surgical robot and greatly reduces the learning and training time of medical staff.

After the 3D structured light camera is applied to a surgical robot, the present invention can quickly and accurately realize the registration of the coordinate system of the surgical robot and the coordinate system of the CT machine. The registration accuracy can reach within 1 mm, providing accurate positioning for the surgical robot to perform puncture surgery. and identification to ensure the accuracy of surgery.

In addition, the present invention greatly simplifies the coordinate registration process during robot surgery through the use of 3D structured light cameras. It has nothing to do with the patient, is simple to operate, and greatly shortens the learning and training time of medical staff. In addition, the 3D structured light camera and the puncture device are installed at the end of the robotic arm, which reduces the size of the surgical robot's equipment and greatly reduces the space occupied by the equipment in the CT operating room. The conventional CT examination room can be fully used, allowing robotic surgery to be used in more of hospitals.

Description of the drawings

Fig. 1 is a flow chart of the method for registering the coordinate system of the surgical robot and the coordinate system of the CT machine in the present invention.

Figure 2 is a schematic structural diagram of a system for registering the surgical robot coordinate system and the CT machine coordinate system in the present invention.

Figure 3 is a schematic structural diagram of the 3D structured light camera and the puncture device in the present invention after they are combined and installed.

Figure 4 is a schematic three-dimensional structural diagram of the calibration plate in the present invention.

Fig. 5 is a schematic structural diagram of the checkerboard structure in the calibration plate substrate of the present invention.

Figure 6 is a schematic cross-sectional structural view of four columnar connectors in the present invention.

Figure 7 is a schematic structural diagram of the working state of the system in the present invention.

Figure 8 is a diagram 1 of the working principle of registration in the present invention.

Figure 9 is the second working principle diagram of registration in the present invention.

Implementation

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the specific embodiments and the accompanying drawings. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention.

As shown in Figures 1, 2, 3, 8 and 9, the method for registering the coordinate system of the surgical robot and the coordinate system of the CT machine in the present invention is to use a 3D vision system to register the coordinate system of the CT machine and the coordinate system of the surgical robot. The robot arm coordinate system is registered, and the 3D structured light camera in the 3D vision system moves synchronously with the robot arm 4 and the puncture device 3 installed at the end of the robot arm.

The 3D vision system used to register the coordinate system of the surgical robot and the coordinate system of the CT machine includes a software part and a hardware part. The software part is combined with the control system of the surgical robot. The specific combination and software program will be determined by those skilled in the art. This can be achieved after a detailed description of the inventive method. The hardware part includes a 3D structured light camera 1 installed on the puncture device 3 at the end of the surgical robot's robotic arm 4, and a calibration plate 2 that can be placed stably on the CT machine. The 3D structured light camera 1 and the puncture device 3 are fixedly installed together through the mounting bracket 32. They are both installed at the end of the robotic arm 4 and move synchronously with the movement of the robotic arm 4 together with the puncture device 3. The specific structures of the fixed installation of the 3D structured light camera 1 and the puncture device 3 and the fixed mounting bracket 32 are easy to implement for those skilled in the art, and will not be described in detail here.

As shown in Figure 3, the 3D structured light camera 1 in the present invention can be split into two parts, including a structured light source 30 and a DDP camera 31, which are respectively installed on both sides of the puncture device 3, so that the puncture needle in the puncture device 3 can 5 is located between the structured light source 30 and the DDP camera 31, and after the structured light source 30 and the DDP camera 31 are fixedly installed, the light source coverage range of the structured light source 30 and the shooting range of the camera 31 overlap exactly and are located below the puncture device 3. Can better identify the puncture location. The 3D structured light camera 1 in the present invention can also be directly fixed and installed on the end of the robotic arm 4 as a whole, as shown in FIGS. 7 and 9 , and is arranged parallel (or side by side) with the puncture device 3 .

As shown in Figure 4, the calibration plate 2 includes a base plate 20, four spherical calibration members 22, four columnar connectors 21 used to fixedly connect the base plate 20 and the spherical calibration members 22, and used to lock the columnar connectors 21 and the base plate. 20 of the four fasteners 23.

The substrate 20 is a square ceramic substrate with a length of 160 mm, a width of 140 mm, and a thickness of 5 mm. Each of the four right-angled positions of the ceramic substrate is provided with a through hole 25. One of the side surfaces of the ceramic substrate 20 is located at four through holes. Logo structures 24 are evenly distributed in the middle of 25 . The logo structure 24 is a geometric figure drawn or printed on the surface of the ceramic substrate 20, as shown in Figure 5. In the present invention, it is preferably black, The white squares are alternately arranged and combined to form a checkerboard pattern. The side length of the black and white squares is 8mm.

The columnar connectors 21 are preferably made of polyformaldehyde thermoplastic crystalline polymer (POM, polyformaldehyde) material. A spherical calibration member 22 is fixed above each columnar connector 21. The spherical calibration member 22 must be clearly visible in the CT machine. For materials that can image without producing artifacts, AL ₂ O ₃ ceramic balls with a diameter of 20 mm are preferred.

The materials used for the cylindrical connector 21 and the spherical calibration member 22 are selected. The density of the spherical calibration member 22 is 1.5-4 times greater than the density of the cylindrical connector 21. It can be accurately and clearly identified from the CT image, and at the same time, it will not appear in the CT image. artifacts are produced.

As shown in FIG. 6 , the cylindrical connector 21 includes a first connection portion 26 connected to the spherical calibration member 22 , a second connection portion 27 connected to the base plate 20 , and a second connection portion for connecting the first connection portion 26 and the second connection portion. 27 to connecting column 28. The first connecting part 26, the second connecting part 27, and the connecting column 28 are integrally formed of polyoxymethylene thermoplastic crystalline polymer material. The heights of the four columnar connectors 21 are all different, and the first connecting portion 26 and the second connecting portion 27 of each columnar connector 21 have the same structure and shape, and the same size. The connecting posts 28 used to connect the first connecting part 26 and the second connecting part 27 have different heights, and the four connecting posts 28 are arranged in an arithmetic sequence, preferably 0 mm, 20 mm, 40 mm, and 60 mm.

The first connecting part 26 is provided with a cylindrical groove 29 inside for the spherical calibration member 22 to sink into. The depth of the groove 29 is greater than the radius of the spherical calibration member 22 but less than 2/3 of the diameter of the spherical calibration member 22. In this embodiment, the depth of the groove 29 is preferably 21 mm, and the diameter is preferably 19.9-20 mm. With the help of the characteristics of the polyoxymethylene thermoplastic crystalline polymer material, the spherical calibration member 22 has a somewhat clamped state when sinking into the groove 29, and it needs to be used a little. Only when the force can enter the groove 29 can the center of the spherical calibration member 22 be completely in the center of the groove 29, and the spherical calibration member 22 will not rotate or move after entering the groove 29, making the spherical calibration member 22 completely in the center of the groove 29. The center of the ball of the calibration member 22 is always at the center of the groove 29 . In order to enable the spherical calibration member 22 to enter the groove 29 smoothly, a ventilation hole 19 is provided at the inner bottom of the groove 29 .

Preferably, the four locking members 23 use hard rubber support columns to ensure that the calibration plate 2 is stable and does not slide when placed on the CT machine.

The size of the checkerboard grid, the columnar connector 21 and the spherical calibration member 22 in the calibration plate 2 of the present invention and their positions in the calibration plate 2 are precisely controlled, which can ensure that the spherical calibration member 22 can be clearly imaged in the CT machine and Artifacts will not be generated, and the spherical calibration member 22 can be stably fixed in the calibration plate, so that the coordinates of the center point of the spherical calibration member 22 in the calibration plate coordinate system are accurate.

As shown in Figure 1, Figure 7, Figure 8 and Figure 9, the method for registering the coordinate system of the surgical robot and the coordinate system of the CT machine in the present invention is used to register the coordinate system of the CT machine and the coordinate system of the robot arm, as follows Steps to perform:

1) Move the robotic arm 4 fixed with the 3D structured light camera 1 to a predetermined surgical area next to the CT machine 6 and fix it. In this step, the robotic arm 4 can be started in advance and moved to a predetermined position.

2) Place the calibration plate 2 on the CT bed of the CT machine 6 and within the range that the 3D structured light camera 1 can capture.

3) Start the registration process, and the robotic arm 4 carries the 3D structured light camera 1 and moves synchronously to the preset first posture (set in the surgical robot program), and performs the following steps:

3.1) Turn on the structured light source 30 in the 3D structured light camera 1, project blue-violet LED light with a wavelength of 490nm to the calibration plate 2, and form a 20-stripe grating on the logo structure 24 of the calibration plate 2, refracted by the blue-violet LED light to the DDP camera 31, convert the Gray code of the grating stripes into real-time data, perform a half-precision matching algorithm through the software, and then form a point cloud image through the patch algorithm, and calculate the content distance of the checkerboard in the mark structure 24 of the calibration plate 2 (checkerboard corner point to distance from the corner point), and then perform a deviation correction calculation based on the true value of the mark structure 24 in the calibration plate 2 to obtain the conversion relationship W _BC1 between the calibration plate coordinate system and the camera coordinate system in the first attitude,

The transformation relationship between the calibration plate coordinate system and the camera coordinate system is called the first transformation matrix W _BC .

The specific algorithm involved in this step is a hand-eye calibration algorithm, which is a well-known technology, and the specific principles and algorithms will not be described in detail.

In this step, the projection wavelength of the blue-violet LED light can be between 450nm and 550nm, and according to different wavelengths, it can have 13-24 stripes. The grating is placed on the calibration plate 2. In this embodiment, the wavelength of 490nm is preferred, and there are 20 stripes. The grating is on the calibration plate 2, which facilitates rapid calculation by computer software.

3.2) Based on the pose transformation parameters of the robot arm in each pose (coordinates x, y, z and angles θ _x , θ _y , θ _z ), obtain the center point of the end of the robot arm in the robot arm coordinate system in the first posture The pose representation, that is, the transformation relationship between the coordinate system of the end center point of the robot arm and the coordinate system of the robot arm in the first posture, is the second transformation matrix W _AT1 .

Specifically, the rotation matrix and translation matrix of the transformation matrix are transformed into a 4×4 homogeneous transformation matrix W _AT :

4) Start the robotic arm 4 to move to the second posture, repeat the above step 3), and obtain the first transformation matrix W _BC2 of the calibration plate coordinate system and the camera coordinate system in the second posture, and the center point of the end of the robotic arm 4 and the mechanical The second transformation matrix W _AT2 of the arm coordinate system;

Repeat this, move the robotic arm 4 to 10 different predetermined postures in sequence, and obtain the first transformation matrix W _BCi in each posture, which is W _BC1 , W _BC2 , W _BC3 , ....W _BC10 ;The second conversion matrix W _ATi is: W _AT1 , W _AT2 , W _AT3 ,…….W _AT10 .

5) Obtain the transformation matrix W _CT between the camera coordinate system and the coordinate system of the center point of the end of the robot arm.

Specifically: select the first transformation matrix W _BCi , W _BCj and the second transformation matrix W ATi , _{W ATj} _of any two poses (i, j) from the 10 poses in step 4), according to the following equation (1 ) can obtain the transformation relationship between the camera coordinate system and the coordinate system of the center point at the end of the manipulator, that is, the transformation matrix W _CT ^(ij) .
W _AT ⁽ⁱ⁾ W _CT ^(ij) W _BC ⁽ⁱ⁾ = W _AT ^(j) W _CT ^(ij) W _BC ^(j) (1)

6) Obtain the transformation matrix W _AB ^(ij) between the calibration plate coordinate system and the robot arm coordinate system.

According to the following equation (2), the transformation relationship between the calibration plate coordinate system and the robot arm coordinate system for the two poses (i, j) is obtained, that is, the transformation matrix is W _AB ^(ij) .
W _AB ^(ij) = W _AT ⁽ⁱ⁾ W _CT ^(ij) W _BC ⁽ⁱ⁾ = W _AT ^(j) W _CT ^(ij) W _BC ^(j) (2)

7) Repeat steps 5) and 6) to select the first transformation matrix W _BC and the second transformation matrix W _AT of two different postures from the 10 postures. After combining the two, 10*9/2=45 can be obtained. transformation matrix W _AB ^(ij) . Calculate the average value for the same variables corresponding to the 45 transformation matrices W _AB ^(ij) , and combine the average values of all the same variables into the transformation relationship between the calibration plate coordinate system and the robot arm coordinate system, which is called the third transformation matrix

It should be noted that the 10 preset poses in this embodiment are based on the structural size of the calibration plate 2 and the characteristic parameters of the 3D structured light camera 1, and the best position that can ensure the measurement accuracy and conversion matrix calculation accuracy is selected. The number of poses can be between 4 and 20, depending on the structural size of the calibration plate 2 and the characteristic parameters of the 3D structured light camera 1.

The same variables refer to specific variables at each same position in the transformation matrix, such as u _ABx , u _ABy , u _ABz , etc.

8) Control the robotic arm 4 to retract, keep the calibration plate 2 stationary on the CT machine 6, and start the CT machine 6 to closely scan the calibration plate 2.

The CT influence data of the four spherical calibration parts 22 on the calibration plate 2 are obtained. The influence data includes the CT values and three-dimensional CT coordinates of all pixels in the image. Through the image recognition algorithm and the sphere center algorithm based on the CT values, the calculation Find the spherical center coordinates of the four spherical calibration parts 22 in the CT coordinate system, represented by the coordinate matrix B, Combining the coordinate matrix of the four spherical calibration parts 22 with the center of the sphere on the calibration plate 2 The following equation relationship can be obtained:

The coordinate matrix B has been obtained. The above equation can be solved to calculate the transformation relationship from the CT coordinate system to the calibration plate coordinate system, which is called the fourth transformation matrix.

9) After obtaining the third transformation matrix W _AB from the calibration plate coordinate system and the robot arm coordinate system, and the fourth transformation matrix W _BD from the CT coordinate system to the calibration plate coordinate system, the CT can be obtained according to the following calculation formula (3) The transformation relationship between the machine coordinate system and the robot arm coordinate system is called the fifth transformation matrix W _AD .

After obtaining the fifth transformation matrix W _AD between the CT coordinate system and the robot arm coordinate system, the coordinate registration of the CT machine coordinate system and the robot arm coordinate system is completed, thus completing the CT machine coordinate system and the surgical robot coordinate system. coordinate registration.

To sum up, the present invention fixes a 3D structured light camera at the end of the robotic arm and adopts a hand-on-eye calibration method. There is no need to use a separate binocular camera, which can effectively reduce various backgrounds in the CT room. The influence of light source on measurement can achieve high measurement accuracy. The theoretical measurement accuracy can reach 0.001mm, and under the scene conditions of the example, the accuracy can reach 0.1mm.

Claims

A method for registering the coordinate system of a surgical robot and the coordinate system of a CT machine, characterized in that a 3D vision system is used to register the coordinate system of the CT machine and the coordinate system of the mechanical arm in the surgical robot, and the 3D vision system The 3D structured light camera moves synchronously with the robotic arm and the puncture device fixedly installed at the end of the robotic arm.
The method for registering the surgical robot coordinate system and the CT machine coordinate system according to claim 1, wherein the 3D vision system includes a device installed at the end of the robotic arm and fixed to the puncture device. The overall 3D structured light camera and the calibration plate can be placed directly on the CT machine and located within the shooting range of the 3D structured light camera.
The method for registering the coordinate system of the surgical robot and the coordinate system of the CT machine according to claim 2, which is used to register the coordinate system of the CT machine and the coordinate system of the robotic arm, is characterized in that it is performed according to the following steps:

1) Move the robotic arm fixed with the 3D structured light camera to the surgical area next to the CT machine;

2) Place the calibration plate on the CT machine and within the range that can be photographed by the 3D structured light camera;

3) Start the registration process. The robotic arm carries the 3D structured light camera and moves to multiple poses in sequence. After moving to each pose, the 3D structured light camera is turned on to project multiple sets of structured light and collect the structured light. Project the photos of the calibration structure in the calibration plate, record the transformation parameters of the robot arm in each posture and the photos of the calibration structure in the calibration plate through computer software, and use the hand-eye calibration algorithm to obtain the coordinate system of the calibration plate. The transformation relationship with the robot arm coordinate system is the third transformation matrix;

4) The robotic arm is retracted to the initial position, the calibration plate continues to be placed on the CT machine and remains motionless, and the CT machine is started to scan the calibration plate; CT scans of the four spherical calibration parts on the calibration plate are obtained. The image data is combined with the coordinate matrix of the spherical center of the four spherical calibration parts against the calibration plate to obtain the conversion relationship between the CT coordinate system and the calibration plate coordinate system, which is the fourth conversion matrix;

5) Obtain the CT machine coordinate system based on the third transformation matrix between the calibration plate coordinate system and the robot arm coordinate system and the fourth transformation matrix between the CT machine coordinate system and the calibration plate coordinate system. The conversion relationship with the robot arm coordinate system is the fifth transformation matrix, which completes the coordinate registration between the CT machine coordinate system and the robot arm coordinate system.
The method for registering the surgical robot coordinate system and the CT machine coordinate system according to claim 3, characterized in that in step 3), the following steps are performed:

3.1) Start the registration procedure. The robotic arm carries the 3D structured light camera and moves to n different preset poses in sequence. After moving to each pose, the calibration plate in each pose is acquired. The conversion relationship between the coordinate system and the camera coordinate system is the first conversion matrix W BC ; the conversion relationship between the end center point of the robotic arm and the robotic arm coordinate system is the second conversion matrix W AT ;

3.2) Select the first transformation matrix W BC and the second transformation matrix W AT corresponding to two of the poses (i, j), and obtain the camera coordinate system and the robot end center point coordinate system according to the following equation (1) The transformation matrix W CT (ij) ;
W AT (i) W CT (ij) W BC (i) = W AT (j) W CT (ij) W BC (j) (1)

3.3) Obtain the two transformation matrices W AB (ij ) of the calibration plate coordinate system and the robot arm coordinate system for the two poses (i, j) according to the following equation (2);
W AB (ij) = W AT (i) W CT (ij) W BC (i) = W AT (j) W CT (ij) W BC (j) (2)

3.4) Repeat steps 3.2) and 3.3) to select the first transformation matrix W BC and the second transformation matrix W AT of two different postures from 2n postures. After combination, n*(n-1)/2 can be obtained the conversion matrices W AB (ij) ; calculate the average value for the same variables corresponding to the n*(n-1)/2 conversion matrices W AB (ij) , and combine the average values of all the same variables into The conversion relationship between the calibration plate coordinate system and the robot arm coordinate system is called the third conversion matrix
The method for registering the surgical robot coordinate system and the CT machine coordinate system according to claim 4, characterized in that in step 3.1), the following steps are performed after the robotic arm moves to each posture:

3.1.1) The 3D structured light camera projects structured light to the calibration plate, collects photos of the mark structure in the calibration plate projected by the structured light, and records the posture transformation parameters of the robotic arm and the structured light by computer software The photo of the landmark structure in the calibration plate is projected onto the camera, and the conversion relationship between the coordinate system of the calibration plate and the center point coordinate system of the 3D structured light camera for this pose is obtained through the hand-eye calibration algorithm, which is the first conversion. matrix W BC ;

3.1.2) Based on the pose transformation parameters of the robot arm in each pose, obtain the pose representation of the center point of the robot arm in the robot arm coordinate system, that is, the coordinate system of the center point of the robot arm end and the coordinates of the robot arm in this pose The conversion relationship between systems is the second conversion matrix W AT .
The method for registering the coordinate system of the surgical robot and the coordinate system of the CT machine according to claim 4, characterized in that in step 3), the number of postures that the 3D structured light camera moves with the robotic arm is 4- An even number between 20.
The method for registering the surgical robot coordinate system and the CT machine coordinate system according to claim 5, characterized in that the 3D structured light camera in step 3.1.1) projects blue-violet LED light with a wavelength of 490 nm. 13-24 fringe gratings to the calibration plate.
The method for registering the surgical robot coordinate system and the CT machine coordinate system according to any one of claims 3 to 7, characterized in that the calibration plate includes a base plate and four spherical calibration parts for fixed connection. The columnar connector between the base plate and the spherical calibration piece is used to lock the columnar connector and the base plate. The height of each columnar connector is distributed in equal rows, and all columnar connectors are They are all fixedly arranged on the same side surface of the base plate, and the base plate is provided with a checkerboard pattern on the side surface where the columnar connector is provided.
The method for registering the coordinate system of the surgical robot and the coordinate system of the CT machine according to claim 8, characterized in that the cylindrical connector includes a first connection portion connected to the spherical calibration member, and the The second connection part for connecting the substrate, the first connection part is provided with a cylindrical groove for the spherical calibration piece to sink into, the depth of the groove is greater than the radius of the spherical calibration piece, and the groove is The inner diameter is less than or equal to the diameter of the spherical calibration component.
A system for the method of registering a surgical robot coordinate system and a CT machine coordinate system according to any one of the above claims 1-9, a 3D system used in conjunction with a surgical robot console, a robotic arm, and a CT machine Structured light camera and calibration plate, characterized in that the 3D structured light camera is fixedly installed with the puncture device installed at the end of the robotic arm, and moves together with the puncture device with the movement of the robotic arm.