阅读说明：本技术 一种用于口腔种植机器人的精确定位及智能导航方法 (Accurate positioning and intelligent navigation method for oral implantation robot ) 是由 刘云峰 阚天舒 王卫彬 程康杰 姜献峰 董星涛 于 2020-02-25 设计创作，主要内容包括：一种用于口腔种植机器人的精确定位及智能导航方法,包括以下步骤：(1)数字化种植牙方案的规划；(2)设计定位标志器的个性化固定结构；(3)设计定位标志器的标准定位支架；(4)定位标志器生成；(5)三维种植方案中的种植体位置坐标获取；(6)口腔碰撞模型的构建；(7)实际场景坐标系构建及校正；(8)机器人运动路径规划及离线编程；(9)机器人种植手术操作。本发明在术前实现三维种植方案中全局坐标系下机器人末端执行器目标位置坐标精确计算、利用机器人接触式位置反馈校正光学定位与导航系统的精度、种植操作的末端执行器碰撞模型构建以及机器人运动动态规划。(An accurate positioning and intelligent navigation method for an oral implantation robot comprises the following steps: (1) planning a digital dental implant scheme; (2) designing an individualized fixing structure of the positioning marker; (3) designing a standard positioning bracket for positioning the marker; (4) generating a positioning marker; (5) acquiring the position coordinates of an implant in a three-dimensional planting scheme; (6) constructing an oral collision model; (7) constructing and correcting an actual scene coordinate system; (8) planning a motion path of the robot and programming the robot off line; (9) robotic implant surgery operations. The invention realizes accurate calculation of the target position coordinates of the robot end effector under the global coordinate system in the three-dimensional planting scheme before operation, corrects the precision of an optical positioning and navigation system by using robot contact type position feedback, constructs an end effector collision model of planting operation and dynamically plans the motion of the robot.)

1. A precise positioning and intelligent navigation method for an oral implantation robot is characterized by comprising the following steps:

(1) planning of digital dental implant plan

The method comprises the steps of acquiring a CBCT image of an oral cavity of a patient and intraoral plaster mold taking or intraoral scanning data aiming at the patient with partial missing teeth of the upper jaw or the lower jaw to be implanted, reconstructing an oral cavity three-dimensional model, finishing placement of an implant in a jaw bone model by utilizing digital implantation software according to model data, determining parameters such as the number, the position, the angle, the depth and the like of the implant, and acquiring a three-dimensional implantation scheme;

(2) personalized fixing structure for designing positioning marker

According to the three-dimensional planting scheme in the step (1), a tooth socket structure without undercut is generated on the remaining teeth by using a guide plate generating function in digital planting software to serve as a personalized fixing structure for fixing a positioning marker and the oral cavity of a patient;

(3) standard positioning support for designing positioning marker

The method comprises the steps that a three-dimensional modeling software is utilized to design an extraoral positioning support, a group of positioning holes are formed in the support and used for the cooperative robot to contact and position in a dragging mode, the real-time position coordinates of the oral cavity of a patient are calculated and used for correcting an optical positioning system, meanwhile, the positioning holes can also be used for installing positioning mark points for visual identification, the positioning support is designed into a standard structure, a plurality of groups with different sizes are provided for selection and storage according to an ST L file, and meanwhile, a two-dimensional checkerboard image three-dimensional model is constructed;

(4) localization marker generation

In the planting scheme design software, a standard positioning support and a two-dimensional checkerboard image three-dimensional model which are designed in advance are called according to the relevant size of a patient data three-dimensional reconstruction model, the standard positioning support and the two-dimensional checkerboard image three-dimensional model are adjusted to be suitable for the positioning of a robot and the operation, the standard positioning support is connected with a personalized fixing structure of a positioning marker, a complete three-dimensional structure of the positioning marker support is formed together with a two-dimensional checkerboard inserted into a positioning hole of the standard positioning support, model data are exported, finally, a real object is printed by further utilizing S L A, a real object plate of the two-dimensional checkerboard image is inserted into a marker support hole, and the accuracy of the mutual positions is checked;

(5) implant position coordinate acquisition in three-dimensional planting scheme

In the planting scheme design software, an oral local coordinate system is constructed based on a positioning marker, the root end position coordinate and the top implantation position coordinate of an implant in a three-dimensional planting scheme are obtained, the implantation angle of the implant is calculated, so that a complete pit preparation pose coordinate is obtained, the coordinate is further recorded in a homogeneous matrix form and is used as a target point to be written in a motion path;

(6) construction of oral Collision model

The method comprises the steps that an oral cavity three-dimensional model comprising a planting scheme and a positioning marker, a planting robot and an end effector are led into a robot simulation system to establish a robot tooth implantation operation simulation scene, obstacles such as the oral cavity three-dimensional model and the planting robot are set as collision models, and the robot is prevented from damaging oral tissue in the tooth implantation process;

(7) actual scene coordinate system construction and correction

Further in an actual scene, the positioning marker is installed on the teeth of a patient through an individualized fixing structure and fixed, the two-dimensional checkerboard is ensured to have the same position as that in the three-dimensional model when being inserted into the positioning hole of the standard positioning support, a binocular vision optical measuring instrument is adopted to measure the marking points on the two-dimensional checkerboard, and the optical measurement coordinates of the positioning support under the global coordinate system of the robot are calculated according to the marking point positions; dragging the robot to enable the tail end of the robot to be in contact with a positioning hole in the positioning support, and obtaining a contact measurement coordinate of the positioning support; comparing the optical measurement coordinate of the positioning bracket with the contact measurement coordinate, taking the contact measurement coordinate as a standard value, obtaining a compensation matrix corrected by the optical positioning system, and correcting the optical positioning system;

(8) robot motion path planning and off-line programming

Preparing pose coordinates through the obtained actual scene coordinate system and the cavity, calculating the final target pose of the robot end effector under the global coordinates, setting a robot motion path point, and further planning a reasonable operation path by using a motion planning algorithm in a motion planning algorithm library to complete robot motion path planning and off-line programming;

(9) robotic implant surgery

The robot finishes the operation under the guidance of the optical positioning navigation system according to the off-line programmed path planning, the operation can be interrupted if a patient needs to have a rest after closing the mouth in the operation, the mouth opening condition and the mouth position of the patient are obtained through the optical positioning system when the operation is continued, the path is dynamically modified on the basis of the planned path, and the robot end effector is guided to move safely, so that the planting operation is finished.

2. The method of claim 1, further comprising the steps of:

(9) intraoperative planting plan adjustment

If an accident situation occurs in the operation and the operation scheme needs to be adjusted temporarily, a doctor drags the robot to determine a new planting position and the pose of the end effector, drags the robot again to set passing waypoints, and obtains a new motion path of the robot by using a path planning algorithm in a motion planning algorithm library so as to guide the robot to complete new operation.

Technical Field

The invention relates to the technical field of oral implanting robots, in particular to a method for accurately positioning and navigating a robot in an implanting operation in a partial tooth missing area, particularly a missing area of a posterior tooth area.

Background

The oral implant is to implant an artificial implant in a jawbone of an edentulous part through an operation, and connect an abutment and a crown thereon to restore functions of chewing, appearance and the like of a patient. The implant is called the third tooth of human body after deciduous tooth and permanent tooth as the first tooth-missing repair method. In the process of oral implantation, the most core surgical operation is the preparation of implant cavities and the implantation of implants in jawbones, and related surgical operations are mainly completed in the forms of free hands, static guide plate guidance, dynamic video navigation, oral implantation robots and the like at present.

The free hand operation means that a doctor holds an implantation operation tool (an implantation mobile phone) by hand and performs operation in the oral cavity of a patient according to own experience and hand feeling. Due to lack of accurate guidance in free hand operation, the deviation between the actual implant position of the implant and the preoperative planning scheme is easily overlarge, and the ideal occlusion relation of a patient cannot be recovered. Incorrect occlusion relation easily causes poor stress of the implant, and a series of complications such as severe bone absorption, implant falling, and implant mechanical fracture caused by stress concentration are caused by combining inherent stress mismatching of a bone-implant interface. Free hand operation also presents a greater risk during cavity preparation, such as side wall perforation of the patient's jaw, damage to the roots of adjacent teeth, or irreversible damage to the mandibular nerve canal, even death of the patient, due to hand gesture deviations. With the development and application of technologies such as CT scanning, computer-aided oral three-dimensional model reconstruction, oral scanning and the like, a three-dimensional planting scheme is designed before an operation, and a navigation planting operation guided by a static guide plate or video dynamic guide is widely applied in the operation. However, the planting operation guided by the guide plate has the defects of difficult heat dissipation, influence on hole preparation operation due to the fact that the guide plate occupies the operation space in the height direction, insufficient flexibility in the operation and the like; in dynamic navigation, a dentist needs to look at a screen for operation, and the intuition is not enough. Meanwhile, the above three implantation and repair methods all require a doctor to hold a tool for operation, and the hands are prone to involuntary shaking, jaw drilling vibration, and uncomfortable postures during operation in a narrow oral cavity are prone to fatigue and poor in visual field, which all easily cause the lack of necessary stability in oral implantation operation.

In recent years, the rapid development of the robot technology, particularly the characteristics of precision, repeatability, stability, safety and the like of robot operation, brings a new idea for medical operations. The application of the robot in the oral implantation field is also deeply researched and is already applied to clinic. For example, the Yomi assisted planting robot system in the United states was approved by the FDA in 2017 and is widely used; and the fully autonomous robot developed by Zhao Iridium folk team of the university of military medical sciences of air force in China also realizes the primary clinical application of the anterior dental area in 2017. With the continuous improvement of intelligent technology, robots with partially autonomous operation capability are becoming the main development direction of oral implant robots. However, since the application of the robot to the oral field is a short time, many problems still need to be solved.

An optical positioning system adopted by the existing planting robot is used for positioning and navigating the robot, but the marker image recognition technology of the optical system is insufficient in precision; meanwhile, in the prior art, a patient who is adopted by an optical system wears a fixed tooth socket (such as a U-shaped tube) of a marker on teeth before an operation to shoot a CT, and the same fixed tooth socket is worn to connect the marker for positioning in the operation, but the fixed tooth socket is a standard component and is not matched with the tooth shape of the patient, fillings such as gutta-percha and the like need to be filled in the fixed tooth socket, and the soft fillings deform, so that the position of the connected marker is further inaccurate, and errors of the optical positioning and navigation system are caused. Errors of a robot positioning and navigation system easily cause inaccurate positioning of an end effector (dental drill) caused by inaccurate coordinates of a target position of the robot, so that the risk of a planting operation is increased, and the precision of the current clinical operation of the planting robot is improved. On the other hand, because the shape of the oral tissue is uncertain after mouth closing and mouth opening, in the process of the robot implantation operation, a patient must keep the mouth opening state for a long time, so that the robot does not collide with the surface in the oral cavity when moving according to the preoperative planned path, and the fatigue and even dislocation of the temporomandibular joint of the robot are easily caused.

Disclosure of Invention

In order to overcome the defects of the prior art and further solve a series of problems that in the robot implantation operation process, an end effector (an implantation mobile phone and a dental drill) is accurately obtained from a target position coordinate in a three-dimensional implantation scheme under a global coordinate system of a robot system, the precision of an optical positioning and navigation system is insufficient, the robot collides with the oral cavity of a patient, the opening time in the operation process is too long and the like, the invention provides an intelligent navigation method which can accurately calculate the target position coordinate of the end effector of the robot under the global coordinate system in the three-dimensional implantation scheme before an operation, correct the precision of the optical positioning and navigation system by using robot contact type position feedback, construct an end effector collision model of implantation operation and dynamically plan the motion of the robot.

The technical scheme adopted by the invention for solving the technical problems is as follows:

an accurate positioning and intelligent navigation method for an oral implantation robot comprises the following steps:

(1) planning of digital dental implant plan

And (3) acquiring a CBCT image of the oral cavity of the patient and intraoral plaster mold taking or intraoral scanning data for the patient with partial missing teeth of the upper jaw or the lower jaw to be implanted, and reconstructing the oral cavity three-dimensional model. According to the model data, the placement of the implant in the jaw bone model is completed by utilizing digital planting software (such as six-dimensional planting software), and parameters such as the number, the position, the angle, the depth and the like of the implant are determined to obtain a three-dimensional planting scheme;

(2) personalized fixing structure for designing positioning marker

According to the three-dimensional planting scheme in the step (1), a guide plate generating function in digital planting software (such as six-dimensional planting design software) is utilized to generate a tooth socket structure without undercut on the remaining teeth, and the tooth socket structure is used as a personalized fixing structure for fixing a positioning marker and the oral cavity of a patient;

(3) standard positioning support for designing positioning marker

The method comprises the steps that a three-dimensional modeling software (such as solidworks) is utilized to design an extraoral positioning support, a group of positioning holes are formed in the support and used for the cooperative robot to contact and position in a dragging mode, the real-time position coordinates of the oral cavity part of a patient are calculated and used for correcting an optical positioning system, and meanwhile, the positioning holes can also be used for installing positioning mark points for visual identification;

(4) localization marker generation

In the planting scheme design software, calling (importing ST L file) a pre-designed standard positioning support and a two-dimensional checkerboard image three-dimensional model according to the relevant size of a patient data three-dimensional reconstruction model, adjusting the standard positioning support and the two-dimensional checkerboard image three-dimensional model to the positions suitable for robot positioning and operation, connecting the standard positioning support with a personalized fixed structure of a positioning marker, forming a complete three-dimensional structure of the positioning marker support together with a two-dimensional checkerboard inserted in a positioning hole of the standard positioning support, exporting model data, finally further printing out a real object by utilizing S L A, inserting the real object plate of the two-dimensional checkerboard image into a marker support hole, and checking the accuracy of the mutual positions;

(5) implant position coordinate acquisition in three-dimensional planting scheme

In the planting scheme design software, an oral local coordinate system is constructed based on a positioning marker, the root end position coordinate and the top implantation position coordinate of an implant in a three-dimensional planting scheme are obtained, the implantation angle of the implant is calculated, so that a complete pit preparation pose coordinate is obtained, the coordinate is further recorded in a homogeneous matrix form and is used as a target point to be written in a motion path;

(6) construction of oral Collision model

Introducing an oral cavity three-dimensional model comprising a planting scheme and a positioning marker, a planting robot, an end effector (a surgical tool) and the like into a robot simulation system (such as ROS) to establish a robot tooth planting operation simulation scene, setting the oral cavity three-dimensional model, the planting robot and other obstacles as collision models, and avoiding the robot from damaging oral tissues in the process of planting teeth;

(7) actual scene coordinate system construction and correction

Further in an actual scene, the positioning marker is installed on the teeth of a patient through an individualized fixing structure and fixed, the two-dimensional checkerboard is ensured to have the same position as that in the three-dimensional model when being inserted into the positioning hole of the standard positioning support, a binocular vision optical measuring instrument is adopted to measure the marking points on the two-dimensional checkerboard, and the optical measurement coordinates of the positioning support under the global coordinate system of the robot are calculated according to the marking point positions; dragging the robot to enable the tail end of the robot to be in contact with a positioning hole in the positioning support, and obtaining a contact measurement coordinate of the positioning support; comparing the optical measurement coordinate of the positioning bracket with the contact measurement coordinate, taking the contact measurement coordinate as a standard value, obtaining a compensation matrix corrected by the optical positioning system, and correcting the optical positioning system;

(8) robot motion path planning and off-line programming

Setting a robot motion path point, and further planning a reasonable operation path by using a motion planning algorithm in a motion planning algorithm library (such as an OMP L motion planning library) to complete robot motion path planning and off-line programming;

(9) robotic implant surgery

The robot completes the operation under the guidance of the optical positioning navigation system according to the off-line programmed path plan. In the operation, if a patient needs to have a rest with a closed mouth, the operation can be interrupted, when the operation is continued, the mouth opening condition and the mouth position of the patient are obtained through the optical positioning system, the path is dynamically modified on the basis of the planned path, and the robot end effector is guided to move safely, so that the planting operation is completed.

Further, the method comprises the following steps:

(10) intraoperative planting plan adjustment

If an accident situation occurs in the operation and the operation scheme needs to be adjusted temporarily, a doctor drags the robot to determine a new planting position and a new pose of the end effector, drags the robot to set a passing waypoint, and obtains a new motion path of the robot by using a path planning algorithm in a motion planning algorithm library (such as an OMP L motion planning library) so as to guide the robot to complete a new operation.

The invention has the following beneficial effects: 1) the scheme improves the positioning navigation precision of the dental implant of the oral implant robot, and corrects the precision of the optical positioning navigation system through the contact measurement of the dragging position feedback of the cooperative robot; 2) the positioning precision of the robot system is further improved by utilizing a positioning scheme combining the personalized tooth upper fixing structure, the standard positioning bracket and the two-dimensional checkerboard; 3) the oral collision model is established in the robot simulation system for path planning, so that the safety of tooth implantation of the robot is improved, and the preoperative preparation work of the robot is greatly simplified; 4) when the intraoperative planting scheme is adjusted clinically, the position is dragged by the cooperative robot to feed back and position, a new robot motion path is planned quickly, and the flexibility of the robot system for implementing the operation is improved; 5) in the robot operation process, the operation is suspended when the patient has a rest with a closed mouth, and when the operation is continued, the optical system acquires the oral cavity position and the mouth opening condition of the patient, so that the operation path is dynamically adjusted, the problem of fatigue of the temporomandibular joint of the patient is effectively solved, and the robot operation system has a positive effect on reducing the labor intensity of doctors.

Drawings

Fig. 1 is a schematic diagram of the precise positioning and navigation of the oral implantation robot with cooperative robot contact type position feedback and optical tracking combined positioning.

Fig. 2 is a schematic side view of a reconstructed jaw bone model and an implantation plan for a missing tooth.

Fig. 3 is a schematic front view of a reconstructed jaw bone model of a missing tooth and an implantation plan.

Fig. 4 is a schematic view of the personalized fixation structure of the position marker.

FIG. 5 is a complete schematic view of a localization marker with personalized fixation structure.

Fig. 6 is a schematic view of an edentulous jaw bone after wearing the positioning marker.

Fig. 7 is a schematic view of a robotic positioning and dental implant procedure.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1 to 7, a precise positioning and intelligent navigation method for an oral implant robot includes the following steps:

(1) planning of digital dental implant plan

And (3) acquiring a CBCT image of the oral cavity of the patient and intraoral plaster mold taking or intraoral scanning data for the patient with partial missing teeth of the upper jaw or the lower jaw to be implanted, and reconstructing the oral cavity three-dimensional model. According to the model data, the placement of the implant in the jaw bone model is completed by utilizing digital planting software (such as six-dimensional planting software), and parameters such as the number, the position, the angle, the depth and the like of the implant are determined to obtain a three-dimensional planting scheme;

(2) personalized fixing structure for designing positioning marker

According to the three-dimensional planting scheme in the step (1), a guide plate generating function in digital planting software (such as six-dimensional planting design software) is utilized to generate a tooth socket structure without undercut on the remaining teeth, and the tooth socket structure is used as a personalized fixing structure for fixing a positioning marker and the oral cavity of a patient;

(3) standard positioning support for designing positioning marker

The method comprises the steps that a three-dimensional modeling software (such as solidworks) is utilized to design an extraoral positioning support, a group of positioning holes are formed in the support and used for the cooperative robot to contact and position in a dragging mode, the real-time position coordinates of the oral cavity part of a patient are calculated and used for correcting an optical positioning system, and meanwhile, the positioning holes can also be used for installing positioning mark points for visual identification;

(4) localization marker generation

In the planting scheme design software, calling (importing ST L file) a pre-designed standard positioning support and a two-dimensional checkerboard image three-dimensional model according to the relevant size of a patient data three-dimensional reconstruction model, adjusting the standard positioning support and the two-dimensional checkerboard image three-dimensional model to the positions suitable for robot positioning and operation, connecting the standard positioning support with a personalized fixed structure of a positioning marker, forming a complete three-dimensional structure of the positioning marker support together with a two-dimensional checkerboard inserted in a positioning hole of the standard positioning support, exporting model data, finally further printing out a real object by utilizing S L A, inserting the real object plate of the two-dimensional checkerboard image into a marker support hole, and checking the accuracy of the mutual positions;

(5) implant position coordinate acquisition in three-dimensional planting scheme

In the planting scheme design software, an oral local coordinate system is constructed based on a positioning marker, the root end position coordinate and the top implantation position coordinate of an implant in a three-dimensional planting scheme are obtained, the implantation angle of the implant is calculated, so that a complete pit preparation pose coordinate is obtained, the coordinate is further recorded in a homogeneous matrix form and is used as a target point to be written in a motion path;

(6) construction of oral Collision model

Introducing an oral cavity three-dimensional model comprising a planting scheme and a positioning marker, a planting robot, an end effector (a surgical tool) and the like into a robot simulation system (such as ROS) to establish a robot tooth planting operation simulation scene, setting the oral cavity three-dimensional model, the planting robot and other obstacles as collision models, and avoiding the robot from damaging oral tissues in the process of planting teeth;

(7) actual scene coordinate system construction and correction

Further in an actual scene, the positioning marker is installed on the teeth of a patient through an individualized fixing structure and fixed, the two-dimensional checkerboard is ensured to have the same position as that in the three-dimensional model when being inserted into the positioning hole of the standard positioning support, a binocular vision optical measuring instrument is adopted to measure the marking points on the two-dimensional checkerboard, and the optical measurement coordinates of the positioning support under the global coordinate system of the robot are calculated according to the marking point positions; dragging the robot to enable the tail end of the robot to be in contact with a positioning hole in the positioning support, and obtaining a contact measurement coordinate of the positioning support; comparing the optical measurement coordinate of the positioning bracket with the contact measurement coordinate, taking the contact measurement coordinate as a standard value, obtaining a compensation matrix corrected by the optical positioning system, and correcting the optical positioning system;

(8) robot motion path planning and off-line programming

Setting a robot motion path point, and further planning a reasonable operation path by using a motion planning algorithm in a motion planning algorithm library (such as an OMP L motion planning library) to complete robot motion path planning and off-line programming;

(9) robotic implant surgery

The robot completes the operation under the guidance of the optical positioning navigation system according to the off-line programmed path plan. In the operation, if a patient needs to have a rest with a closed mouth, the operation can be interrupted, when the operation is continued, the mouth opening condition and the mouth position of the patient are obtained through the optical positioning system, the path is dynamically modified on the basis of the planned path, and the robot end effector is guided to move safely, so that the planting operation is completed.

Further, the method comprises the following steps:

(10) intraoperative planting plan adjustment

If an accident situation occurs in the operation and the operation scheme needs to be adjusted temporarily, a doctor drags the robot to determine a new planting position and a new pose of the end effector, drags the robot to set a passing waypoint, and obtains a new motion path of the robot by using a path planning algorithm in a motion planning algorithm library (such as an OMP L motion planning library) so as to guide the robot to complete a new operation.

Referring to fig. 1, the precise positioning and intelligent navigation device for the oral implantation robot comprises a manipulator control system 2, a positioning marker 3, an optical positioning system 5, a computer and a display 7, wherein the manipulator comprises a six-degree-of-freedom cooperative mechanical arm 1 and an implantation mobile phone 8, the computer is connected with the six-degree-of-freedom cooperative mechanical arm 1 through the control system 2, the implantation mobile phone 8 is installed at the tail end of the six-degree-of-freedom cooperative mechanical arm through a clamp holder, the positioning marker 3 consists of an intraoral personalized fixing structure and an extraoral positioning structure, the positioning structure is provided with a plurality of marking points, and meanwhile, an optical tracking marker can be installed.