CN115337072A - Acetabulum rasp angle calibration method and system based on optical positioning - Google Patents

Abstract

The invention discloses a method and system for calibrating the angle of acetabular reaming based on optical positioning. and the first angle increment, according to the initial angle and the first angle increment, the manipulator and the optical locator perform angle hand-eye calibration through the angle calibrator, and output the optimal hand-eye transformation matrix; initialize the angle of the manipulator and the optical locator , to obtain the second angle increment, and construct the optimal hand-eye transformation relationship according to the optimal hand-eye transformation matrix; according to the second angle increment and the optimal hand-eye transformation relationship, the mechanical arm and the optical positioner perform angle calibration to adjust the actuator position attitude until the feedback adjustment condition is met, and the angle calibration is completed. On the premise of angle calibration, the angle accuracy of acetabular reaming is further improved, the error is reduced, and the complexity of multiple adjustments of the existing manual dragging robotic arm is solved.

Description

A method and system for calibrating the angle of acetabular reaming based on optical positioning

technical field

The invention relates to the technical field of mechanical arm application, in particular to a method and system for calibrating the angle of acetabular reaming based on optical positioning.

Background technique

In total hip arthroplasty, the angle of acetabular reaming is very important in total hip arthroplasty. In order to ensure the correct placement of the joint prosthesis structure, it is necessary to accurately ream the acetabulum according to the preoperatively planned reaming angle. . When the acetabulum is reamed by the method of hand-eye calibration with the robotic arm, the robotic arm needs to be adjusted in real time through the observation data many times during the operation. The accuracy of the hand-eye calibration will affect the accuracy of the robotic arm movement. There may be a certain error between the angle and the angle actually controlled by the robotic arm, and it is difficult to accurately judge the angle of the acetabular reamer in real time during the operation.

Contents of the invention

The object of the present invention is to provide a method and system for calibrating the angle of acetabular reaming based on optical positioning, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

The solution of the present invention to solve the technical problem is to provide a method and system for calibrating the angle of acetabular reaming based on optical positioning.

According to the embodiment of the first aspect of the present invention, a method for calibrating the angle of acetabular reaming based on optical positioning is provided, including: establishing the base coordinate system of the mechanical arm corresponding to the mechanical arm and the optical system coordinate system corresponding to the optical positioner, Wherein, the end of the mechanical arm is provided with an actuator and an angle calibrator, and the angle calibrator is installed on the actuator in parallel and is located within the visual range of the optical locator;

Obtain the planned initial angle and the first angle increment of the manipulator, according to the initial angle and the first angle increment, the manipulator and the optical positioner perform hand-eye calibration of the angle through the angle calibrator, and output the optimal hand-eye transformation matrix ;

Initializing the angle of the mechanical arm and the optical locator, obtaining a second angle increment, and constructing an optimal hand-eye conversion relationship according to the optimal hand-eye conversion matrix;

According to the second angle increment and the optimal hand-eye conversion relationship, the mechanical arm and the optical positioner perform angle calibration, and adjust the pose of the actuator until the feedback adjustment condition is satisfied, and the angle calibration is completed.

Further, the angle initialization of the mechanical arm and the optical positioner specifically includes:

Move the actuator at the end of the robotic arm to the set initial pose;

Track and position the optical locator to the angle calibrator to obtain the initial angle information in the coordinate system of the optical system.

Further, according to the second angle increment and the optimal hand-eye conversion relationship, the mechanical arm and the optical positioner perform angle calibration, and adjust the pose of the actuator until the feedback adjustment condition is met. The completion of the angle calibration specifically includes:

According to the second angle increment, the first angle information expected to be output by the optical locator is obtained, wherein the first angle information is the sum of the initial angle information and the second angle increment;

Input the first angle information into the optimal hand-eye transformation relationship, and obtain the theoretical angle information of the angle calibrator in the base coordinate system of the manipulator;

According to the theoretical angle information, the pose of the actuator at the end of the mechanical arm is adjusted, and the optical positioner tracks and positions the angle calibrator to obtain second angle information;

Obtaining an angle difference according to the first angle information and the second angle information, and judging whether the angle difference is smaller than a set angle difference threshold;

If so, complete the angle calibration, output the first angle information, if not, update the angle information input to the optimal hand-eye conversion relationship, and perform angle calibration again

Further, the updating of the angle information input to the optimal hand-eye conversion relationship, and performing angle calibration again specifically includes: adding the first angle information to the angle difference to obtain third angle information, and inputting the third angle information into In the optimal hand-eye conversion relationship, the angle calibration is performed again.

Further, the acquisition of the planned initial angle of the manipulator and the first angle increment, according to the initial angle and the first angle increment, the manipulator and the optical positioner perform hand-eye calibration of the angle through the angle calibrator, and output the optimal The hand-eye transformation matrix specifically includes:

Obtain the planned initial angle and first angle increment of the mechanical arm, and control the rotation of the actuator at the end of the mechanical arm according to the initial angle and the first angle increment;

During the rotation of the actuator, several angle information of the angle calibrator in the optical system coordinate system are acquired and sampled to form the first angle point set, and several angle information in the base coordinate system of the manipulator are sampled to form second angle pair point set;

Based on the improved SVD algorithm, the point set of the first angle and the point set of the second angle are processed to obtain a hand-eye transformation matrix;

According to the hand-eye transformation matrix, use the first angle to invert the point set to obtain the theoretical angle point set of the angle calibrator in the coordinate system of the manipulator, and use the second angle to invert the point set and the theoretical angle point set Error calculation, judging whether the hand-eye transformation matrix is an optimal solution according to the error calculation result;

If not, update the first angle pair point set and the second angle pair point set according to the error calculation result, and then return to recalculate a new hand-eye transformation matrix;

If so, directly output the optimal hand-eye transformation matrix.

According to the embodiment of the second aspect of the present invention, an optical positioning-based acetabular reaming angle calibration system is provided, which is applied to an optical positioning-based acetabular reaming angle calibration method in the embodiment of the first aspect of the present invention , including: optical positioner, actuator, angle calibrator and mechanical arm;

The actuator is installed on the end of the mechanical arm for grinding the acetabulum, the angle calibrator is installed on the actuator, parallel to the actuator, and the angle calibrator is located at the end of the optical positioner within sight;

The optical locator is used to track and position the angle calibrator, and obtain angle information of the angle calibrator, and the mechanical arm is used to adjust the pose of the actuator.

Further, the angle calibrator includes: three calibration balls, a fixed bracket and a fixed rod;

The three calibration balls are fixed on the top of the fixed bracket by threads, and the bottom of the fixed bracket is connected with the actuator through the fixed rod, and the three calibration balls are all located within the visible range of the optical locator.

Further, an optical positioning-based acetabular reaming angle calibration system further includes: a tripod; the top of the tripod is connected to the bottom of the optical locator, and the tripod fixes and supports the optical locator.

The beneficial effects of the present invention are: by obtaining the optimal hand-eye transformation matrix, constructing the optimal hand-eye transformation relationship, and then adjusting the actuator according to the planned second angle increment, measuring the filing angle in real time during the filing process, and real-time Adjust the actuator according to the feedback error for angular calibration. The angle feedback adjustment is added to further improve the angle accuracy of acetabular reaming and reduce errors. The invention simply and effectively solves the problem that the mechanical arm automatically adjusts the angle to be close to the expected value during the operation. At the same time, it avoids the difficulty that the existing mechanical arm needs to adjust in real time through the observation data many times during the operation.

Description of drawings

Fig. 1 is a schematic flowchart of a method for calibrating the angle of acetabular reaming based on optical positioning provided by an embodiment of the present invention;

Fig. 2 is a schematic flowchart of a method for calibrating the angle of acetabular reaming based on optical positioning provided by another embodiment of the present invention;

Fig. 3 is a schematic flowchart of a method for calibrating the angle of acetabular reaming based on optical positioning provided by another embodiment of the present invention;

Fig. 4 is a structural schematic diagram of an acetabular reaming angle calibration system based on optical positioning provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of an acetabular reaming angle calibration system based on optical positioning provided by another embodiment of the present invention.

Reference signs: 100, optical positioner, 200, actuator, 300, angle calibrator, 310, calibration ball, 320, fixed bracket, 330, fixed rod, 400, mechanical arm, 500, triangular fixed frame.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, but not to limit the present invention.

It should be noted that although the functional modules are divided in the schematic diagram of the system, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the flow chart. The terms "first", "second" and the like in the specification and claims and the above drawings are used to distinguish similar objects, and not necessarily used to describe a specific sequence or sequence.

In the description of the present invention, it should be noted that unless otherwise clearly defined, terms such as installation, installation, and connection should be understood in a broad sense, and those skilled in the art can reasonably determine the meaning of the above terms in this document in combination with the specific content of the technical solution. The specific meaning of the invention.

Referring to FIG. 1 , in some embodiments of the first aspect of the present invention, a method for calibrating the angle of acetabular reaming based on optical positioning includes the following steps:

S100, establish the base coordinate system of the manipulator corresponding to the manipulator and the coordinate system of the optical system corresponding to the optical locator, wherein the end of the manipulator is provided with an actuator and an angle calibrator, and the angle calibrator is installed on the actuator in parallel and located on the optical positioner. Within the visible range of the locator;

In this embodiment, a certain distance is maintained between the robotic arm and the optical positioner. The end of the mechanical arm is equipped with an actuator and an angle calibrator. The actuator is used to sharpen the acetabulum. The angle calibrator is within the visual range of the optical positioner. The angle calibrator is designed as an asymmetric structure and is installed parallel to the actuator. device. The optical locator can track and position the angle calibrator and obtain the angle information of the angle calibrator. The angle calibrator includes: three calibration balls, a fixed bracket and a fixed rod. The rigid body coordinates are established by three asymmetric calibration balls on the fixed bracket system to obtain the Euler angle data of the rigid body, that is to say, the optical locator can track and locate the calibration ball, and obtain the angle information of the calibration ball in real time. The coordinate system is established by three non-linear rigid body calibration spheres. As the actuator rotates, the calibration spheres are captured by the optical locator with a wide field of view. The angle calibrator is placed on the end effector in parallel, the structure is simple, the calibration process is easy to operate and implement, and the angle information is output in real time under the optical positioning system.

The built-in controller of the robotic arm can also obtain the angle value of the calibration ball in the base coordinate system of the robotic arm through the rigid body components such as the size parameters of the calibration ball, the length of the fixed bracket, and the length of the fixed rod. Calibration through the rigid body structure helps to improve calibration The precision of the work.

S200, obtaining the planned initial angle and the first angle increment of the manipulator, and according to the initial angle and the first angle increment, the manipulator and the optical positioner perform hand-eye calibration of the angle through the angle calibrator, and output an optimal hand-eye transformation matrix ;

In this embodiment, an initial angle of movement of the robotic arm and a first angular increment of movement of the robotic arm are planned. Obtain the planned initial angle and the first angle increment, and the external computer sends an operation command to the built-in controller of the manipulator to control the actuator at the end of the manipulator to rotate from the initial angle according to the first angle increment. For example: when the actuator at the end of the mechanical arm moves to the parallel and horizontal plane, set the angle at this time as the initial angle, and send an operation command to the built-in controller of the mechanical arm through the external computer, so that the mechanical arm can increment according to the planned angle Movement, according to the rotation process of the actuator, the mechanical arm and the optical positioner perform angle hand-eye calibration through the angle calibrator, and output the optimal hand-eye transformation matrix.

S300, initialize the angle of the manipulator and the optical locator, obtain the second angle increment, and construct the optimal hand-eye conversion relationship according to the optimal hand-eye conversion matrix;

In this embodiment, after the hand-eye calibration of the angle of the mechanical arm and the optical positioner is completed, the poses of the two remain unchanged. The instrument performs angle initialization, and obtains the second angle increment according to the planning acetabular reaming angle. Through the optimal hand-eye transformation matrix obtained in S200, an optimal hand-eye transformation relationship is constructed. Among them, the hand-eye transformation matrix represents the transformation relationship between the base coordinate system of the manipulator and the coordinate system of the optical system, and is actually composed of a rotation matrix R and a translation matrix T. According to the optimal rotation matrix R and translation matrix T, the optimal hand-eye transformation relationship B _j =A _i ×R+T is constructed.

S400, according to the second angle increment and the optimal hand-eye conversion relationship, the mechanical arm and the optical positioner perform angle calibration, adjust the pose of the actuator until the feedback adjustment conditions are met, and complete the angle calibration.

In this embodiment, according to the obtained second angle increment and the optimal hand-eye conversion relationship, the manipulator and the optical positioner perform angle calibration through the angle calibrator, and control the manipulator to adjust the pose of the actuator until the feedback adjustment is satisfied. condition, the actuator is no longer adjusted, and the calibration of the angle is completed.

After the actuator at the end of the mechanical arm completes the angle calibration, the optical positioner is used to track the angle calibrator in real time to obtain the angle information. According to the second angle increment, the actuator can reach the desired grinding angle and adjust it. On the premise of angle calibration Further improve the accuracy and solve the complexity of multiple adjustments of the existing manual dragging robotic arm. At the same time, it avoids the difficulty that the existing mechanical arm needs to adjust in real time through the observation data many times during the operation.

Referring to FIG. 2 , in some embodiments of the first aspect of the present invention, at S200, the planned initial angle of the manipulator and the first angle increment are obtained, and according to the initial angle and the first angle increment, the manipulator and the optical positioner pass The angle calibrator performs the hand-eye calibration of the angle, and outputs the optimal hand-eye transformation matrix, which specifically includes:

S210, acquiring the planned initial angle and first angle increment of the mechanical arm, and controlling the rotation of the actuator at the end of the mechanical arm according to the initial angle and the first angle increment;

In this embodiment, the initial angle of the robotic arm is planned, and the external computer sends an operation command to the built-in controller of the robotic arm to control the actuator at the end of the robotic arm to circle the base of the robotic arm in first angle increments from the initial angle. The x, y, z axis rotation of the coordinate system. For example: when the actuator at the end of the mechanical arm moves to the parallel and horizontal plane, set the angle at this time as the initial angle, and send an operation command to the built-in controller of the mechanical arm through the external computer, so that the actuator at the end of the mechanical arm is executing When the position of the grinding head of the device remains unchanged, it rotates around the x, y, and z axes of the base coordinate system of the mechanical arm according to the first angle increment.

S220, during the rotation process of the actuator, obtain and sample several angle information of the angle calibrator in the optical system coordinate system to form a first angle point set, and obtain and sample several angle information in the base coordinate system of the manipulator form the second set of angle pairs;

In this embodiment, during the rotation of the actuator, several angle information of the angle calibrator in the optical system coordinate system are acquired and sampled to form the first angle pair point set A _i ={A ₁ ,A ₂ , ...,A _i }, and obtain several angle information in the base coordinate system of the manipulator and sample to form the second angle pair point set B _i ={B ₁ ,B ₂ ,...,B _i }, where i=1 ,2,...,n; n is the number of angle information samples sampled in the present invention, n is a positive integer and n≥4.

S230, based on the improved SVD algorithm, the first angle pair point set and the second angle pair point set are processed to obtain a hand-eye transformation matrix;

In this embodiment, the first angle pair point set A _i ={A ₁ ,A ₂ ,...,A _i } and the second angle pair point set B _i ={B ₁ ,B ₂ ,...,B _i } into the decentralization formula:

再通过第一加权平均中心

和第一角度对点集A_i＝{A₁,A₂,…,A_i}得到第一角度标定点集A_j＝{A₁,A₂,…,A_j}；将第二角度对点集B_i＝{B₁,B₂,…,B_i}代入去中心化公式，得到第二加权平均中心

再通过第二加权平均中心

和第二角度对点集B_i＝{B₁,B₂,…,B_i}得到第二角度标定点集B_j＝{B₁,B₂,…,B_j}。In the formula, P _i is the source-to-point set, and P _j is the decentralized point set. Substitute the first angle pair point set A _i ={A ₁ ,A ₂ ,…,A _i } into the decentralized formula to obtain the first weighted mean center

Then through the first weighted average center

and the first angle pair point set A _i ={A ₁ ,A ₂ ,…,A _i } to obtain the first angle calibration point set A _j ={A ₁ ,A ₂ ,…,A _j }; the second angle pair Point set B _i ={B ₁ ,B ₂ ,…,B _i } is substituted into the decentralization formula to get the second weighted mean center

Then through the second weighted average center

and the second angle pair point set B _i ={B ₁ ,B ₂ ,...,B _i } to obtain the second angle calibration point set B _j ={B ₁ ,B ₂ ,...,B _j }.

Based on the improved SVD algorithm, the data after decentralized processing is used to solve the problem, and the hand-eye transformation matrix is obtained. The hand-eye transformation matrix represents the transformation relationship between the base coordinate system of the manipulator and the coordinate system of the optical system, and is actually composed of the rotation matrix R and a translation matrix T. Solving the rotation matrix R and the translation matrix T based on the SVD algorithm by using the centrally processed data belongs to the prior art, and will not be repeated in this embodiment.

S240, according to the hand-eye transformation matrix, use the first angle to invert the point set to obtain the theoretical angle point set of the angle calibrator in the coordinate system of the manipulator, and calculate the error between the point set and the theoretical angle point set through the second angle, and judge Whether the hand-eye transformation matrix is the optimal solution;

In this embodiment, according to the hand-eye transformation matrix, the point set A _i ={A ₁ ,A ₂ ,…,A _i } is inverted using the first angle of the angle calibrator in the optical system coordinate system to obtain the angle calibration The theoretical angle point set B _j ={B ₁ ,B ₂ ,…,B _j } of the device in the mechanical arm coordinate system, through the second angle point set B _i ={B ₁ ,B ₂ ,…,B _i } and The theoretical angle point set B _j ={B ₁ ,B ₂ ,…,B _j } is used for error calculation to obtain the error point set e, e=B _j -B _i , and judge whether the hand-eye transformation matrix is the optimal solution according to the error calculation, Judgment results include: if there is one or more differences in the error point set e greater than the preset error threshold β, then it is judged that the hand-eye transformation matrix is not the optimal solution, and step S250 is continued at this time; if the error point set e contains If all the differences are less than or equal to the preset error threshold β, then it is judged that the hand-eye transformation matrix is the optimal solution, and then skip to step S260.

S250, if not, update the first angle pair point set and the second angle pair point set according to the error calculation result, and then return to recalculate a new hand-eye transformation matrix;

In this embodiment, the unqualified difference is screened out from the error point set e, and the unqualified difference is greater than the preset error threshold β, and the first angle pair point set and the second angle pair point set have unqualified The angle values related to the qualified difference are deleted, the update is completed, and the updated first angle pair point set and the second angle pair point set are used to return to recalculate a new hand-eye transformation matrix.

S260, if yes, directly output the optimal hand-eye transformation matrix.

By collecting multiple sets of angular sample points under the coordinate system of the optical locator and the base of the manipulator. In the traditional SVD algorithm, the error threshold screening is added to calculate the hand-eye transformation matrix, and the hand-eye calibration of the angle is performed to improve the accuracy of the initial calibration, and then the angle feedback is used to further improve the execution accuracy of the angle calibration. Solve the complexity of multiple adjustments of the existing manual dragging mechanical arm. At the same time, it avoids the difficulty that the existing mechanical arm needs to adjust in real time through the observation data many times during the operation.

Referring to FIG. 3, in some embodiments of the first aspect of the present invention, in S300, initializing the angle of the robotic arm and the optical positioner specifically includes:

S310, moving the actuator at the end of the mechanical arm to the set initial pose;

In this embodiment, after the hand-eye calibration of the angle of the mechanical arm and the optical positioner is completed, the postures of the two remain unchanged, and the rasp angle of the acetabulum is planned according to the postures at this time. The robot arm moves autonomously, so that the actuator at the end of the robot arm moves to the planned initial pose. Complete the angle initialization of the robotic arm.

S320, tracking and positioning the angle calibrator with the optical locator, and obtaining initial angle information in the coordinate system of the optical system.

In this embodiment, the actuator has moved to the initial pose, and the optical locator tracks and positions the angle calibrator to obtain initial angle information A ₀ of the angle calibrator in the optical system coordinate system. Complete the angle initialization of the optical positioner.

Referring to Fig. 3, in some embodiments of the first aspect of the present invention, in S400, according to the second angle increment and the optimal hand-eye conversion relationship, the mechanical arm and the optical positioner perform angle calibration to adjust the pose of the actuator, Until the feedback adjustment conditions are met, the completion of the angle calibration includes:

S410. Obtain first angle information expected to be output by the optical locator according to the second angle increment, where the first angle information is the sum of the initial angle information and the second angle increment;

In this embodiment, after the actuator moves according to the planned second angle increment S, the optical positioner tracks and positions the angle calibrator, and is expected to output the first angle information A ₁ , wherein the first angle information A ₁ is the sum of the initial angle information and the second angle increment, A ₁ =A ₀ +S.

For example: the initial angle information A ₀ is the rasp anteversion angle of 15° and the rasp abduction angle of 35°, and the doctor plans the second increment S to increase the rasp anteversion angle by 3° and the rasp abduction angle by 2°. After the actuator moves, the optical positioner tracks and positions the angle calibrator, and the output first angle information A ₁ is the rasp anteversion angle of 18° and the rasp abduction angle of 37°.

S420, inputting the first angle information into the optimal hand-eye conversion relationship, and solving to obtain the theoretical angle information of the angle calibrator in the base coordinate system of the mechanical arm;

In this embodiment, the estimated _first angle information A1 is input into the optimal hand-eye conversion relationship, wherein the optimal hand-eye conversion relationship is:

_Bj = _Ai ×R+T,

In the formula, B _j is the theoretical angle point set B _j = {B ₁ , B ₂ ,...,B _j } of the angle calibrator in the base coordinate system of the manipulator, and A _i is the first angle point set of the angle calibrator in the optical system coordinate system An angle pair point set A _i ={A ₁ ,A ₂ ,…,A _i }, R is the optimal rotation matrix, T is the optimal translation matrix, and the first angle information A ₁ Convert to the base coordinate system of the manipulator for representation, and obtain the theoretical angle information B ₁ , that is, obtain the theoretical angle information B ₁ theoretically reached by the angle calibrator in the base coordinate system of the manipulator.

S430, adjust the pose of the actuator at the end of the mechanical arm according to the theoretical angle information, and the optical positioner tracks and positions the angle calibrator to obtain second angle information;

In this embodiment, according to the theoretical angle information B ₁ , the pose of the actuator at the end of the manipulator is adjusted so that the actuator reaches the pose corresponding to the theoretical angle information B ₁ , that is, the angle calibrator is in the base coordinate system of the manipulator The angle information below is theoretical angle information B ₁ . When the pose of the actuator at the end of the mechanical arm is adjusted, the optical locator tracks and locates the angle calibrator, and obtains the second angle information A ₂ of the angle calibrator in the optical coordinate system.

S440. Obtain an angle difference value according to the first angle information and the second angle information, and judge whether the angle difference value is smaller than a set angle difference threshold;

In this embodiment, the difference calculation is performed on the _first angle information A1 and the _second angle information A2 to obtain the angle difference E, wherein the angle difference E is the expected arrival of the angle calibrator in the optical coordinate system The angle value between the first angle information A ₁ and the actually arrived second angle information A ₂ . The angle difference E is compared with the set angle difference threshold α, and it is judged whether the angle difference E is smaller than the preset angle difference threshold α set by the technician.

For example: when the first angle information A ₁ that the angle calibrator arrives in the optical coordinate system is expected to be the rasp anteversion angle of 18° and the rasp abduction angle of 37°, the actuator adjusts the posture according to the second increment S, so that The _second angle information A2 reached by the angle calibrator in the optical coordinate system is the rasp anteversion angle of 17° and the rasp abduction angle of 36°, then the angle difference E includes a rasp angle difference of 1° and an abduction angle difference of 1° , is compared with the preset angle difference threshold α set by the technician, and it is judged whether the angle difference E at this time is smaller than the preset angle difference threshold α set by the technician.

S450, if yes, complete the angle calibration, and output the first angle information, if not, update the angle information input to the optimal hand-eye conversion relationship, and perform angle calibration again.

In this embodiment, the corresponding judgment results include: when the angle difference E is less than the preset angle difference threshold α set by the technician, it is considered that the angle calibration is completed, and the _first angle information A1 is output to the external computer Middle; when the angle difference E is greater than the preset angle difference threshold α set by the technician, it is considered that the angle calibration is not completed, and the first angle information A ₁ that the angle calibrator expects to arrive at the angle calibrator in the optical coordinate system and The angle value gap between the actually arrived _second angle information A2 is relatively large, and at this time, the implantation of the prosthesis is likely to affect the patient. Therefore, the angle information input to the optimal hand-eye conversion relationship is updated, and the angle calibration is performed again.

In this embodiment, updating the angle information input to the optimal hand-eye conversion relationship, and performing angle calibration again specifically includes: adding the first angle information to the angle difference to obtain the third angle information, and inputting the third angle information to the optimal Excellent hand-eye conversion relationship. That is to say, the first angle information A ₁ is updated by adding the angle difference E to obtain the third angle information A ₃ , and the third angle information A ₃ is input into the angle information of the optimal hand-eye conversion relationship, and the angle calibration is performed again.

After the angle calibration of the end effector of the robotic arm is completed, the doctor plans the angle of the surgical knife, and according to the expected input angle information, the angle information of the theoretical arrival angle of the robotic arm can be obtained through angle hand-eye conversion calculation. After the robot arm adjusts the pose of the actuator at the end of the robot arm, the rough calibration can be completed, combined with the optical locator to track the actual angle information output by the angle calibrator in real time, and further verify the error through the actual angle information and the expected input angle information If the error between the two exceeds the preset angle difference threshold set by the technician, the input angle information is automatically fed back and adjusted until the requirements are met. Angle feedback is added to the operation to further improve the accuracy of angle calibration, reduce the adjustment of the angle during the operation to the reasonable angle range of real-time observation, and shorten the operation time.

Referring to Fig. 4 and Fig. 5, according to the embodiment of the second aspect of the present invention, an acetabular reaming angle calibration system based on optical positioning is provided, which is applied to an optical positioning-based reaming angle calibration system in the embodiment of the first aspect of the present invention An acetabular reaming angle calibration method, a system for calibrating an acetabular reaming angle based on optical positioning includes: an optical positioning instrument 100 , an actuator 200 , an angle calibrator 300 and a mechanical arm 400 . The actuator 200 is installed on the end of the mechanical arm 400. The actuator 200 is used for grinding the acetabulum. The angle calibrator 300 is installed on the actuator 200. The angle calibrator 300 is parallel to the actuator 200. The angle calibrator 300 is located in the optical within the visible range of the locator 100. The optical locator 100 is used to track and locate the angle calibrator 300 and obtain angle information of the angle calibrator 300 , wherein the optical locator 100 adopts binocular infrared optical positioning technology. The robotic arm 400 is used to adjust the pose of the actuator 200 . A certain distance is maintained between the mechanical arm 400 and the optical locator 100 , so that the angle calibrator 300 is within the visual range of the optical locator 100 . This system uses the optical locator 100 to track the marked points on the angle calibrator 300 in real time during the operation, and outputs the corresponding angle information. Compared with the prior art, the operation is more efficient.

Referring to FIG. 4 , according to some embodiments of the second aspect of the present invention, the angle calibrator 300 includes: three calibration balls 310 , a fixing bracket 320 and a fixing rod 330 . The three calibration balls 310 are fixed on the top of the fixing bracket 320 through threads, and the bottom of the fixing bracket 320 is connected with the actuator 200 through the fixing rod 330 . The angle calibrator 300 is designed as an asymmetric structure, and is installed on the actuator 200 in parallel. The rigid body coordinate system is established by three asymmetric calibration spheres 310 on the fixed bracket 320, and the Euler angle data of the rigid body is obtained, that is to say, the optical locator 100 can track and position the calibration sphere 310, and obtain the angle of the calibration sphere 310 in real time information. The coordinate system is established by three non-linear rigid body calibration balls 310. When the actuator 200 rotates, the calibration ball 310 is captured by the optical locator 100 with a wide field of view, which can effectively avoid the overlapping of optical positioning caused by different angles of rotation. The impact on the tool tracking effect, and the disassembly and assembly of the structure is simple and practical, the calibration process is easy to operate and implement, and the angle information is output in real time under the optical positioning system. The design and processing costs of the angle calibrator 300 are relatively low, and the calibration ball 310 is highly expandable and adjustable.

Referring to FIG. 5 , according to some embodiments of the second aspect of the present invention, a system for calibrating the angle of acetabular reaming based on optical positioning further includes: a tripod 500 ; the top of the tripod 500 and the optical positioner 100 The bottom is connected, and the tripod 500 fixes and supports the optical locator 100 . In this embodiment, it is also possible to adjust the height of the tripod 500 so that the angle calibrator 300 falls within the visual range of the optical locator 100 .

The preferred embodiments of the present invention have been described in detail above, but the invention is not limited to the described embodiments, and those skilled in the art can also make various equivalent modifications or replacements without violating the spirit of the present invention. , these equivalent modifications or replacements are all included within the scope defined by the claims of the present application.

Claims (8)

1. a kind of acetabular reaming angle calibration method based on optical positioning, it is characterized in that, comprising: Establish the base coordinate system of the manipulator corresponding to the manipulator and the coordinate system of the optical system corresponding to the optical locator, wherein the end of the manipulator is provided with an actuator and an angle calibrator, and the angle calibrator is installed on the actuator in parallel and located in the optical positioner. Within the visible range of the locator; Obtain the planned initial angle and the first angle increment of the manipulator, according to the initial angle and the first angle increment, the manipulator and the optical positioner perform hand-eye calibration of the angle through the angle calibrator, and output the optimal hand-eye transformation matrix ; Initializing the angle of the mechanical arm and the optical locator, obtaining a second angle increment, and constructing an optimal hand-eye conversion relationship according to the optimal hand-eye conversion matrix; According to the second angle increment and the optimal hand-eye conversion relationship, the mechanical arm and the optical positioner perform angle calibration, and adjust the pose of the actuator until the feedback adjustment condition is satisfied, and the angle calibration is completed. 2. A method for calibrating the angle of acetabular reaming based on optical positioning according to claim 1, wherein said initializing the angle of said mechanical arm and optical positioner specifically comprises: Move the actuator at the end of the robotic arm to the set initial pose; Track and position the optical locator to the angle calibrator to obtain the initial angle information in the coordinate system of the optical system. 3. A method for calibrating the angle of acetabular reaming based on optical positioning according to claim 2, characterized in that, according to the second angle increment and the optimal hand-eye conversion relationship, the mechanical arm and the optical positioner perform an angle calibration. Calibration, adjusting the pose of the actuator until the feedback adjustment conditions are met, and completing the angle calibration includes: According to the second angle increment, the first angle information expected to be output by the optical locator is obtained, wherein the first angle information is the sum of the initial angle information and the second angle increment; Input the first angle information into the optimal hand-eye transformation relationship, and obtain the theoretical angle information of the angle calibrator in the base coordinate system of the manipulator; According to the theoretical angle information, the pose of the actuator at the end of the mechanical arm is adjusted, and the optical positioner tracks and positions the angle calibrator to obtain second angle information; Obtaining an angle difference according to the first angle information and the second angle information, and judging whether the angle difference is smaller than a set angle difference threshold; If yes, the angle calibration is completed, and the first angle information is output; if not, the angle information input to the optimal hand-eye conversion relationship is updated, and the angle calibration is performed again. 4. A method for calibrating the angle of acetabular reaming based on optical positioning according to claim 3, characterized in that, the updating of the angle information input to the optimal hand-eye conversion relationship, and re-calibrating the angle specifically includes: The first angle information is added to the angle difference to obtain the third angle information, and the third angle information is input into the optimal hand-eye conversion relationship, and the angle calibration is performed again. 5. A method for calibrating the angle of acetabular reaming based on optical positioning according to claim 4, characterized in that, the acquisition of the planned initial angle and the first angle increment of the mechanical arm is based on the initial angle and the first angle increment. One angle increment, the manipulator and the optical positioner perform angle hand-eye calibration through the angle calibrator, and output the optimal hand-eye transformation matrix, which specifically includes: Obtain the planned initial angle and first angle increment of the mechanical arm, and control the rotation of the actuator at the end of the mechanical arm according to the initial angle and the first angle increment; During the rotation of the actuator, several angle information of the angle calibrator in the optical system coordinate system are acquired and sampled to form the first angle point set, and several angle information in the base coordinate system of the manipulator are sampled to form second angle pair point set; Based on the improved SVD algorithm, the point set of the first angle and the point set of the second angle are processed to obtain a hand-eye transformation matrix; According to the hand-eye transformation matrix, use the first angle to invert the point set to obtain the theoretical angle point set of the angle calibrator in the coordinate system of the manipulator, and use the second angle to invert the point set and the theoretical angle point set Error calculation, judging whether the hand-eye transformation matrix is an optimal solution according to the error calculation result; If not, update the first angle pair point set and the second angle pair point set according to the error calculation result, and then return to recalculate a new hand-eye transformation matrix; If so, directly output the optimal hand-eye transformation matrix. 6. A kind of acetabular reaming angle calibration system based on optical positioning, it is characterized in that, be applied to a kind of acetabular reaming angle calibration method based on optical positioning according to any one of claims 1 to 5, comprising: Optical positioners, actuators, angle aligners and robotic arms; The actuator is installed on the end of the mechanical arm for grinding the acetabulum, the angle calibrator is installed on the actuator, parallel to the actuator, and the angle calibrator is located at the end of the optical positioner within sight; The optical locator is used to track and position the angle calibrator, and obtain angle information of the angle calibrator, and the mechanical arm is used to adjust the pose of the actuator. 7. The acetabular reaming angle calibration system based on optical positioning according to claim 6, wherein the angle calibrator comprises: three calibration balls, a fixed bracket and a fixed rod; The three calibration balls are fixed on the top of the fixed bracket by threads, and the bottom of the fixed bracket is connected with the actuator through the fixed rod, and the three calibration balls are all located within the visible range of the optical locator. 8. A kind of acetabular reaming angle calibration system based on optical positioning according to claim 7, further comprising: a tripod mount; the top of the tripod mount is connected to the bottom of the optical positioner, the The above-mentioned tripod fixing frame fixes and supports the optical locator.

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