CN113842217B

CN113842217B - Method and system for limiting motion area of robot

Info

Publication number: CN113842217B
Application number: CN202111035714.2A
Authority: CN
Inventors: 张逸凌; 刘星宇
Original assignee: Longwood Valley Medtech Co Ltd
Current assignee: Zhang Yiling; Longwood Valley Medtech Co Ltd
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2022-07-01
Anticipated expiration: 2041-09-03
Also published as: WO2023029922A1; CN113842217A

Abstract

The application discloses a method and a system for limiting a motion area of a robot. The method comprises the following steps: establishing a stiffness-damping model of a virtual spring according to displacement offsets of an actuator at the tail end of a mechanical arm of the robot in the directions of multiple degrees of freedom from an actual position; setting stiffness values of each of the virtual springs in a plurality of degrees of freedom to define movement of the actuator over a pre-planned target area. The method adopts a virtual spring stiffness-damping model, sets the stiffness in each degree of freedom direction, and can limit the movement in each degree of freedom direction, when external force acts on each degree of freedom, the displacement is very small in the direction of the degree of freedom with high stiffness, and even the displacement can not be generated, so that the actuator can be limited on a target area, and the actuator is prevented from deviating from the target area to cause injury to a patient.

Description

Method and system for limiting motion area of robot

Technical Field

The application relates to the technical field of medical instruments, in particular to a method and a system for limiting a robot motion area.

Background

In the existing operation, when a robot is used for assistance, a doctor holds a mechanical arm of the robot for operation. During operation, due to carelessness, active or passive force may be too hard in places where the force is not applied, so that the saw blade at the end of the mechanical arm exceeds a predetermined operation area, thereby causing unnecessary injury to a patient.

Disclosure of Invention

The main objective of the present application is to provide a method and a system for defining a robot motion area, so as to define an actuator at the end of a robot arm within a target area, thereby improving safety.

In order to achieve the above object, according to an aspect of the present application, there is provided a method of defining a robot movement region, including:

establishing a stiffness-damping model of a virtual spring according to displacement offsets of an actuator at the tail end of a mechanical arm of the robot in the directions of multiple degrees of freedom from an actual position;

setting stiffness values of each of the virtual springs in a plurality of degrees of freedom to define movement of the actuator over a pre-planned target area.

In one embodiment, a direction in which the actuator cuts into the target region is referred to as a depth direction, a direction in the target region and perpendicular to the depth direction is referred to as a lateral direction, and a direction perpendicular to the target region is referred to as a vertical direction;

the stiffness value of each of the virtual springs set in a plurality of degrees of freedom directions includes:

setting the stiffness value of the virtual spring in the depth direction, the stiffness value of the virtual spring in the transverse direction and the stiffness value of the virtual spring in the vertical direction in the direction of translational freedom;

the stiffness value of the virtual spring in the depth direction is equal to or less than the stiffness value of the virtual spring in the transverse direction;

the stiffness value of the virtual spring in the transverse direction is smaller than that of the virtual spring in the vertical direction;

the stiffness value of the virtual spring in the depth direction and the stiffness value of the virtual spring in the transverse direction are both smaller than or equal to a first translational preset stiffness threshold, and the stiffness value of the virtual spring in the vertical direction is larger than or equal to a second translational preset stiffness threshold.

In one embodiment, setting the stiffness value of each of the virtual springs in the plurality of degrees of freedom comprises:

setting, in a rotational degree of freedom direction, a stiffness value of a virtual spring in a direction of axial rotation with the depth direction as an axis, a stiffness value of a virtual spring in a direction of axial rotation with the lateral direction as an axis, and a stiffness value of a virtual spring in a direction of axial rotation with the vertical direction as an axis;

the stiffness value of the virtual spring taking the vertical direction as the axis rotation direction is smaller than the stiffness value of the virtual spring taking the depth direction as the axis rotation direction and smaller than the stiffness value of the virtual spring taking the transverse direction as the axis rotation direction;

the stiffness value of the virtual spring taking the vertical direction as the axis rotation direction is smaller than or equal to a first rotation preset stiffness threshold value;

and the rigidity value of the virtual spring taking the depth direction as the shaft rotation direction and the rigidity value of the virtual spring taking the transverse direction as the shaft rotation direction are greater than or equal to a second rotation preset rigidity threshold value.

In one embodiment, the first translational preset stiffness threshold is 0N/m to 500N/m;

the second translational preset rigidity threshold value is 4000N/m-5000N/m;

the first rotational preset stiffness threshold is 0 Nm/rad-20 Nm/rad;

the second rotation preset rigidity threshold value is 200 Nm/rad-300 Nm/rad.

In one embodiment, damping values for the virtual spring in multiple degrees of freedom are set.

In one embodiment, the target region comprises: a femoral anterior resection plane, a femoral anterior oblique resection plane, a femoral posterior condylar resection plane, a femoral posterior oblique resection plane, a femoral distal resection plane, and a tibial resection plane.

In order to achieve the above object, according to a second aspect of the present application, there is provided a system for defining a motion region of a robot, the system including:

the model establishing module is used for establishing a stiffness-damping model of the virtual spring according to displacement offsets of an actuator at the tail end of a mechanical arm of the robot in the directions of multiple degrees of freedom and an actual position;

and the rigidity setting module is used for setting the rigidity value of each virtual spring in a plurality of freedom degrees so as to limit the movement of the actuator on a pre-planned target area.

In one embodiment, a direction in which the actuator cuts into the target region is referred to as a depth direction, a direction perpendicular to the depth direction within the target region is referred to as a lateral direction, and a direction perpendicular to the target region is referred to as a vertical direction;

the stiffness setting module is further used for setting the stiffness value of the virtual spring in the depth direction, the stiffness value of the virtual spring in the transverse direction and the stiffness value of the virtual spring in the vertical direction in the direction of translational freedom;

the stiffness value of the virtual spring in the transverse direction is greater than the stiffness value of the virtual spring in the vertical direction;

In one embodiment, the stiffness setting module is further configured to set, in a rotational degree of freedom direction, a stiffness value of a virtual spring in a direction of rotation about the depth direction as an axis, a stiffness value of a virtual spring in a direction of rotation about the lateral direction as an axis, and a stiffness value of a virtual spring in a direction of rotation about the vertical direction as an axis;

In one embodiment, the stiffness setting module is further configured to set the first translational preset stiffness threshold to be 0N/m to 500N/m;

the second translational preset rigidity threshold value is 4000N/m-5000N/m;

the first rotational preset stiffness threshold is 0 Nm/rad-20 Nm/rad;

the second rotation preset rigidity threshold value is 200 Nm/rad-300 Nm/rad.

In one embodiment, the system for defining a robot motion zone further comprises a damping setting module for setting damping values of the virtual spring in a plurality of degrees of freedom.

In a third aspect, the present application further provides an electronic device, including: at least one processor and at least one memory; the memory is to store one or more program instructions; the processor is configured to execute one or more program instructions to perform any of the methods described above.

In a fourth aspect, the present application also proposes a computer-readable storage medium having embodied therein one or more program instructions for executing the method of any one of the above.

In the embodiment of the application, a stiffness-damping model of a virtual spring is established according to displacement offsets of an actuator at the tail end of a mechanical arm of a robot in the directions of multiple degrees of freedom and an actual position; setting stiffness values of each of the virtual springs in a plurality of degrees of freedom to define movement of the actuator over a pre-planned target area. Through the rigidity value of the spring of setting for each degree of freedom, on the big degree of freedom direction of rigidity value, the executor is difficult to take place the displacement, and the doctor hardly promotes, just so can inject the executor on the target area, avoid bringing the injury for the patient, very big improvement the security of operation.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, serve to provide a further understanding of the application and to enable other features, objects, and advantages of the application to be more apparent. The drawings and their description illustrate the embodiments of the invention and do not limit it. In the drawings:

fig. 1 is a flow chart of a method of defining a robot motion zone according to an embodiment of the application;

FIG. 2 is a schematic diagram of a stiffness-damping model of a virtual spring according to an embodiment of the present application;

FIG. 3 is a schematic illustration of multiple degrees of freedom orientation of an actuator according to an embodiment of the present application;

FIG. 4A is a schematic illustration of an osteotomy anterior-posterior comparison in accordance with an embodiment of the present application;

FIG. 4B is a schematic view of a femur in a first orientation according to an embodiment of the present application;

FIG. 4C is a schematic view of a femur in a second orientation according to an embodiment of the present application;

FIG. 4D is a schematic view of a third orientation of a femur according to an embodiment of the present application;

FIG. 4E is a schematic view of a fourth orientation of a femur according to an embodiment of the present application;

FIG. 4F is a schematic view of a fifth orientation of a femur according to an embodiment of the present application;

fig. 4G is a schematic view of a tibia according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a system for defining a robot motion zone according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of an apparatus for defining a motion region of a robot according to an embodiment of the present application.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In the present application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are used primarily to better describe the invention and its embodiments and are not intended to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.

Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meanings of these terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

Furthermore, the terms "mounted," "disposed," "provided," "connected," and "sleeved" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

The method for limiting the robot motion region can be applied to a method for limiting a robot osteotomy plane for knee joint replacement, and can also be applied to a method for limiting a motion region of a robot in other fields.

The method for defining the motion area of the robot refers to a flow chart of a method for defining the motion area of the robot shown in fig. 1; the method comprises the following steps:

step S102, establishing a stiffness-damping model of a virtual spring according to displacement offset of an actuator at the tail end of a mechanical arm of the robot in a plurality of freedom degree directions and an actual position.

The stiffness-damping model of the virtual spring is also referred to as Cartesian damping Control Mode (CICM). In the damping control mode the robot is compliance sensitive and can react to external influences, such as obstacles or process forces. Application of an external force may move the robot away from the planned orbital path.

This model is based on a virtual spring and damper implementation that varies in extension with the difference between the current measurement and the specified position of the TCP (Tool Center Point). The spring is characterized by a stiffness value (stiff) and the damper is characterized by a damping value (damming). These parameters can each be set individually in each translational or rotational dimension.

The virtual spring relaxes if the measured robot position corresponds to the specified robot position. Since the robot is now compliant in its behavior, external forces or motion commands cause deviations between the position set point and the actual value of the robot. This causes the virtual spring to deflect, producing a force that complies with hooke's law. The resultant force F can be calculated according to hooke's law, using the set spring rate C and offset Δ x: f ═ C · Δ x.

Referring to FIG. 2, a schematic diagram of a stiffness-damping model of a virtual spring is shown; wherein 1 is spring bias; 2 is a virtual spring; 3 is the actual position; 4 is force; and 5 is the set point position. The spring rate determines how well the robot yields to external forces and deviates from its planned path.

Step S104, setting rigidity values of each virtual spring in a plurality of freedom degrees to limit the movement of the actuator on a preset target area.

Specifically, when the spring rates in the different degrees of freedom are set, the setting can be performed using a function setstifness (…) (type: double).

For use in knee replacement surgery, the target region may be a target plane, i.e. an osteotomy plane, and specifically, the target region may include: osteotomy planes at a plurality of different locations on the femur and tibia.

Illustratively, in any one osteotomy plane, a relatively large stiffness value is set in a direction perpendicular to the osteotomy plane, the stiffness value being greater than a predetermined threshold value to limit movement of the actuator in the direction perpendicular to the osteotomy plane, thereby effectively avoiding deviation of the actuator from the osteotomy plane. The preset threshold value can be flexibly set, when a doctor pushes the mechanical arm, if the actuator deviates in the direction perpendicular to the osteotomy plane, the mechanical arm can output corresponding feedback force (resistance), the doctor can feel the resistance, knows that the actuator deviates undesirably, and does not push the mechanical arm by force.

In specific implementation, after the actuator is aligned with the current target area, the actuator is started, and at the moment, the control robot enters a state of a virtual spring damping model, in the state, the whole mechanical arm can be regarded as an approximate virtual spring, and after force is applied in any direction, the virtual spring follows hooke's law. Illustratively, especially in the direction perpendicular to the osteotomy plane, if the rigidity of the direction is large, the deviation of the actuator in the direction is small, so that the actuator can be stably limited on the osteotomy plane, and the actuator is prevented from exceeding the osteotomy plane, especially the actuator can be effectively prevented from moving in the direction perpendicular to the osteotomy plane, thereby reducing the actuator exceeding the target area to the maximum extent and reducing the accidental injury to the patient.

For convenience of description, referring to fig. 3, the cutting depth direction of the actuator is denoted as the depth direction and is denoted by symbol X. The direction within the region of the actuator perpendicular to the cutting direction of the actuator is denoted as the cross direction and is denoted by the symbol Y. The direction perpendicular to the actuator plane is denoted as the vertical direction and is denoted by the symbol Z.

The degrees of freedom include two kinds of degrees of freedom, i.e., translational degrees of freedom and rotational degrees of freedom, which will be described in the following in two cases.

In one embodiment, when the stiffness values of the virtual springs in the plurality of degrees of freedom are set, the stiffness value of the virtual spring in the depth direction, the stiffness value of the virtual spring in the lateral direction, and the stiffness value of the virtual spring in the vertical direction are set in the translational degree of freedom direction.

Specifically, the stiffness value of the virtual spring in the depth direction is equal to or smaller than the stiffness value of the virtual spring in the lateral direction; the stiffness value of the virtual spring in the lateral direction is greater than the stiffness value of the virtual spring in the vertical direction. And the stiffness value of the virtual spring in the depth direction and the stiffness value of the virtual spring in the transverse direction are both smaller than or equal to the first translational preset stiffness threshold value.

For example, the first translational preset stiffness threshold may range from 0N/m to 500N/m. Therefore, the range of the stiffness value of the virtual spring in the depth direction X and the range of the stiffness value of the virtual spring in the lateral direction Y can be limited to the range of 0N/m to 500N/m. Of course, other ranges of values may be set as appropriate. The principle is that the stiffness setting is relatively small, because according to hooke's law, the smaller the stiffness, the larger the amount of spring deflection when the force is constant. Therefore, the rigidity in the depth direction is set to be as small as possible, and the actuator can be displaced in this direction to cut. In the transverse direction Y, the stiffness provided is also relatively small, which also facilitates the movement of the actuator in this direction for cutting. The depth direction and the transverse direction are both on the osteotomy plane, and the rigidity values of the actuator in the two directions are set to be smaller, so that the actuator can perform cutting motion conveniently.

For a vertical direction, a stiffness value of the virtual spring in the vertical direction is greater than or equal to a second translational preset stiffness threshold. The second translational preset stiffness threshold may be 4000N/m to 5000N/m. From the above, the stiffness in the vertical direction Z of the target region was the largest, and the set range was 4000N/m to 5000N/m. Of course, the setting can be flexibly performed according to actual conditions. The principle is to be as large as possible. Because the greater the stiffness, the smaller the amount of spring deflection when the force is constant, according to hooke's law. Therefore, setting the stiffness in the Z-direction as large as possible can help to avoid displacement of the blade in the Z-direction, which is not allowed if the actuator is caused to directly leave the predetermined osteotomy plane after the displacement in the Z-direction, which is likely to cause injury to the patient.

In one embodiment, the stiffness value of each of the virtual springs in the plurality of degrees of freedom is set in the rotational direction with the depth direction X as the axis;

the stiffness value of the virtual spring in the axial rotation direction by taking the transverse direction Y as an axis;

and the rigidity value of the virtual spring in the axial rotation direction is taken as the vertical direction Z.

Specifically, the stiffness value of the virtual spring in the vertical direction Z as the axial rotation direction is smaller than the stiffness value of the virtual spring in the depth direction X as the axial rotation direction and smaller than the stiffness value of the virtual spring in the lateral direction Y as the axial rotation direction.

The stiffness value of the virtual spring in the direction of rotation of the axis with the vertical direction Z is less than or equal to a first rotational preset stiffness threshold. Optionally, the first rotational preset stiffness threshold is 0 Nm/rad-20 Nm/rad, so that the actuator can rotate in the current target region with the vertical direction Z as an axis,

the stiffness value of the virtual spring in the axial rotation direction with the depth direction X as the axis and the stiffness value of the virtual spring in the axial rotation direction with the transverse direction Y as the axis are greater than or equal to a second rotation preset stiffness threshold value.

The second rotation preset rigidity threshold is 200 Nm/rad-300 Nm/rad, so that the displacement of the actuator in rotation with the depth direction X as an axis and the transverse direction Y as an axis is limited, the actuator is further prevented from being separated from the current target area, and the safety of osteotomy is ensured.

In an alternative embodiment, the preset stiffness value of the virtual spring in the depth direction X and the preset stiffness value of the virtual spring in the lateral direction Y may both be 0N/m, the preset stiffness value of the virtual spring in the vertical direction Z may be 5000N/m, the stiffness value of the virtual spring in the rotational direction with the vertical direction Z as the axis may be 10 Nm/rad, and the stiffness value of the virtual spring in the rotational direction with the depth direction X as the axis and the stiffness value of the virtual spring in the rotational direction with the lateral direction Y as the axis may both be 300 Nm/rad.

In one embodiment, the method of defining further comprises: damping values of the virtual spring in a plurality of degrees of freedom are set. Wherein the spring damping determines the degree of oscillation of the virtual spring after the virtual spring has been displaced from the central position. The damping value may range from 0.1 to 1.0, for example, 0.7.

Specifically, the damping value is set using the following function:

setdamming (…) Spring damping (type: double).

The oscillation coefficient for all degrees of freedom is 0.1-1.0; default value is 0.7.

In the robot API, the cartesian damping control mode is given by the enumeration CartDOF (package com. The enumerated values may be used to describe individual degrees of freedom or may be a combination of degrees of freedom.

A translational degree of freedom in the CartDOF.X direction;

translation freedom in the CartDOF.Y direction;

translation freedom in the CartDOF.Z direction;

transfer X, Y and a combination of translational degrees of freedom in the Z direction;

a degree of freedom of rotation of cartdof.a about the Z-axis;

cartdof.b rotational degrees of freedom about the Y axis;

c rotational degree of freedom about the X axis;

rot X, Y in combination with rotational degrees of freedom in the Z-axis;

all combinations of all cartesian degrees of freedom;

by setting the stiffness to the maximum allowed value (5000) in the direction of the Z-axis, setting the stiffness to a small value (0-500) in the X, Y directions, while setting the stiffness to the maximum allowed value (300) in the direction of the rotational degrees of freedom B, C, and setting the stiffness to a small value (0-100) in the direction of the rotational degrees of freedom A about the Z-axis, the motion of the TCP point of the end-of-arm tool can be confined to the XOY plane and can be turned in a small range on the XOY plane.

The corresponding codes are as follows:

CartesianImpedanceControlModeimpedanceMode＝newCartesianImpedanceContr olMode()；

impedanceMode.parametrize(CartDOF.A).setStiffness(10)；

impedanceMode.parametrize(CartDOF.B).setStiffness(300)；

impedanceMode.parametrize(CartDOF.C).setStiffness(300)；

impedanceMode.parametrize(CartDOF.Z).setStiffness(5000)；

impedanceMode.parametrize(CartDOF.X).setStiffness(0)；

impedanceMode.parametrize(CartDOF.Y).setStiffness(0)；

impadancemode (cartdof. all) setDamping (1); setting spring damping as 1 for all combinations of all Cartesian degrees of freedom;

motioncontainer＝lbr.moveAsync(positionHold(impedanceMode,-1,TimeUnit.SEC ONDS))。

in one embodiment, for use in knee replacement surgery, the target area comprises: a femoral anterior resection plane, a femoral anterior oblique resection plane, a femoral posterior condylar resection plane, a femoral posterior oblique resection plane, a femoral distal resection plane, and a tibial resection plane.

See figure 4A for a schematic representation of a pre-and post-osteotomy comparison. Specifically, referring to fig. 4B, the dark gray covering area is the area of the non-anterior femur to be resected, which is the plane of the anterior femur resection. Referring to fig. 4C, the dark gray coverage area is the area of the anterior oblique resection of the femur, which is the plane of the anterior oblique resection of the femur. Referring to fig. 4D, the dark gray area is the area of the posterior femoral condyle to be resected, which is the resected plane of the posterior femoral condyle. Referring to fig. 4E, the dark gray area is the resected femoral posterior oblique resection plane. Referring to fig. 4F, the dark gray area is the distal femur osteotomy area, which is the distal femur osteotomy plane after being cut away, and the light gray area is a schematic diagram of the saw blade. Referring to fig. 4G, the dark gray area is the tibial plateau area, which is truncated to form the tibial osteotomy plane.

In order to determine the osteotomy plane, a prosthesis model needs to be determined before operation, and a target region is determined according to the prosthesis model, in a second aspect, the present application further provides a method for preoperative planning, specifically including the following steps:

after a medical image of the knee joint is obtained, segmenting and three-dimensionally reconstructing the medical image to obtain a three-dimensional skeleton model of the knee joint;

determining bone key parameters based on the three-dimensional bone model; determining the type and model of a three-dimensional bone prosthesis model based on the bone key parameters;

specifically, after obtaining the three-dimensional bone model of each bone region, the bone key anatomical points may include bone key anatomical points, bone key axes, and bone size parameters, and the bone key anatomical points may be identified based on a deep learning algorithm, such as a neural network model, and the identified bone key anatomical points may be marked on the three-dimensional bone model.

The bone dimensions may include the lateral diameter of the femur, the anteroposterior diameter of the femur, the lateral diameter of the tibia, and the anteroposterior diameter of the tibia, the lateral diameter of the femur being determined from a line connecting the medial and lateral edges of the femur, the anteroposterior diameter of the femur being determined from a line connecting the anterior cortex of the femur and the posterior condyles of the femur, the lateral diameter of the tibia being determined from a line connecting the medial and lateral edges of the tibia, and the anteroposterior diameter of the tibia being determined from a line connecting the anterior and posterior edges of the tibia.

The bone key axes are determined based on the bone key anatomical points, and the bone key angles are determined based on the bone key axes. And the determination of the type and model of the three-dimensional bone prosthesis model is facilitated based on the bone key axis and the bone key angle. Three-dimensional skeletal prosthesis models of knee joints generally include a three-dimensional femoral prosthesis model, a three-dimensional tibial prosthesis, and a shim model connecting the three-dimensional tibial prosthesis model and the three-dimensional femoral prosthesis model.

The three-dimensional bone prosthesis model can be a prosthesis model for total knee replacement in the existing market, the three-dimensional bone prosthesis model has multiple types, and each type of three-dimensional bone prosthesis model has multiple types. For example, the types of three-dimensional femoral prosthesis models are ATTUNE-PS, ATTUNE-CR, SIGMA-PS150, etc., and the types of ATTUNE-PS are 1, 2, 3N, 4N, 5N, 6N.

For example, the implementation manner of the system for determining the model number of the prosthesis through the interactive interface may include: configuration items of each three-dimensional bone prosthesis model can be set on the interface, for example, the configuration items of the three-dimensional femoral prosthesis model, the three-dimensional tibial prosthesis model and the three-dimensional shim model can be set, when one of the configuration items is triggered (for example, the configuration item is triggered in a selected mode), a corresponding prosthesis library can be automatically matched, then which prosthesis model in the prosthesis library is triggered is detected, and a triggered prosthesis signal is used as a replacement prosthesis. For example, when the configuration item of the femoral prosthesis model is triggered, the configuration item can be associated with the femoral prosthesis library, then the type and the model number of all prosthesis models in the femoral prosthesis library are displayed on the interface, and then it is detected which type of femoral prosthesis model and which model number of femoral prosthesis model under the type are triggered, so that the triggered femoral prosthesis model is selected as the femoral prosthesis model.

Implanting the selected three-dimensional bone prosthesis model into the three-dimensional bone model;

adjusting a placement position and a placement angle of the three-dimensional bone prosthesis model based on the bone key parameters and the type and model of the three-dimensional bone prosthesis model.

Specifically, the matching adjustment process and the matching effect of the bone and the prosthesis are displayed in a three-dimensional visual mode. After the three-dimensional bone model implanted with the three-dimensional bone prosthesis model is obtained, whether the femur prosthesis model is installed and adapted with the three-dimensional femur model or not can be determined based on the femur valgus angle, the femur varus angle, the femur supination angle, the femur internal rotation angle, the femur left-right diameter and the femur front-back diameter.

Whether the tibial prosthesis model is installed and matched with the three-dimensional tibial model can be determined based on the tibial varus angle, the femoral valgus angle, the tibial left-right diameter and the tibial anteroposterior diameter.

In one embodiment, the three-dimensional bone model comprises a three-dimensional femoral model, the three-dimensional bone prosthesis model comprises a three-dimensional femoral prosthesis model, the bone key parameters comprise femoral key parameters, the femoral key parameters comprise a femoral mechanical axis, a femoral condyle access line, a posterior condylar junction line, a femoral left-right diameter, and a femoral anterior-posterior diameter;

the step of adjusting the placement position and the placement angle of the three-dimensional bone prosthesis model based on the bone key parameters and the type and model of the three-dimensional bone prosthesis model comprises:

adjusting the placement position of the three-dimensional femoral prosthesis model based on the femoral right-left diameter and the femoral anterior-posterior diameter;

adjusting the varus angle or valgus angle of the three-dimensional femoral prosthesis model to enable the cross section of the three-dimensional femoral prosthesis model to be perpendicular to the mechanical axis of the femur;

and adjusting the internal rotation angle or the external rotation angle of the three-dimensional femoral prosthesis to enable the femoral posterior condylar angle PCA (included angle between the projection line of the femoral condyle through line and the posterior condylar connecting line on the cross section) to be within a preset range.

In this optional implementation manner, when the placement position of the femoral prosthesis model satisfies that the femoral prosthesis model can cover the left and right sides of the femur, and the front and back of the femur, the installation position is appropriate.

Determining a femur valgus angle and a femur varus angle according to the relative angles of a central axis of the femur prosthesis model in the up-down direction of the coronal plane and a femur force line based on the current position of the femur prosthesis model, and determining a supination angle and an internal rotation angle according to the relative angles of a transverse axis of the femur prosthesis model and a through condyle line; the femoral flexion angle is determined by the angle of the mechanical axis of the femur and the central axis of the femoral prosthesis model in the anterior-posterior direction of the sagittal plane. By adjusting the above-mentioned angles, it is possible to determine whether the installation angle of the three-dimensional femoral prosthesis model is proper, for example, when the varus/valgus angle is adjusted to 0 ° and the PCA is adjusted to 3 °, it is determined that the seating position and seating angle of the femoral prosthesis model are adjusted to proper positions.

In one embodiment, the three-dimensional bone model further comprises a three-dimensional tibial model, the three-dimensional femoral prosthesis model further comprises a three-dimensional tibial prosthesis model; the bone key parameters also comprise tibia key parameters, and the tibia key parameters comprise a tibia mechanical axis, a tibia left-right diameter and a tibia front-back diameter;

adjusting the placement position of the three-dimensional tibial prosthesis model based on the left-right diameter of the tibia and the anterior-posterior diameter of the tibia;

and adjusting the varus angle or valgus angle of the three-dimensional tibial prosthesis to ensure that the mechanical tibial axis is vertical to the cross section of the three-dimensional tibial prosthesis.

In one embodiment, after the step of adjusting the placement position and placement angle of the three-dimensional bone prosthesis model, the method further comprises:

performing simulated osteotomy based on the matching relationship between the three-dimensional skeleton prosthesis model and the three-dimensional prosthesis model to obtain a three-dimensional skeleton postoperative simulation model;

performing motion simulation including a straightening position and a bending position on the three-dimensional femoral post-operation simulation model;

determining a straightening gap in a straightening state and a buckling gap in a buckling state;

and comparing the extension gap with the flexion gap, and performing matching verification on the three-dimensional bone prosthesis model.

In this alternative implementation, the bone osteotomy thickness is determined according to the bone prosthesis model design principle, and different bone prosthesis models may correspond to different osteotomy thicknesses; after the osteotomy thickness is determined based on the bone prosthesis model and the bone prosthesis model is matched with the bone, the osteotomy plane of the bone can be determined.

After the placement position and the placement angle of the three-dimensional skeleton prosthesis model are adjusted, simulation osteotomy is performed based on the matching relationship between the three-dimensional skeleton prosthesis model and the three-dimensional skeleton model, and a three-dimensional skeleton postoperative simulation model is obtained.

After the three-dimensional bone postoperative simulation model is obtained, motion simulation is carried out, and the extension gap and the flexion gap can be determined through the extension position simulation diagram and the flexion position simulation diagram. And determining whether the three-dimensional bone prosthesis model is matched with the three-dimensional bone model after osteotomy based on the extension gap and the flexion gap. Whether the size and the position of the prosthesis are proper or not can be observed from different angles through simulating the installation effect of the prosthesis, whether collision and dislocation of the prosthesis occur or not can be observed, and whether the prosthesis is matched with bones or not can be accurately determined. The user can determine whether the bone prosthesis model needs to be adjusted through the final simulation image, and if the type and the model of the bone prosthesis are replaced, the prosthesis library can be called again, and the replaced three-dimensional bone postoperative simulation model is generated based on the new bone prosthesis model. By simulating the expected effect after the operation, the final bone prosthesis model can be matched with the knee joint of the patient.

The gap can be accurately determined by performing postoperative simulation on the bone model for installing the prosthesis model, so that the defect of low operation precision caused by evaluation of indexes such as gap balance, prosthesis position installation and the like completely by subjective feeling depending on the technology and experience of an operator in the related technology is overcome.

In one embodiment, the preoperative planning method further comprises: determining three-dimensional coordinates of a femoral medullary cavity center point based on the three-dimensional femoral model; creating an intramedullary positioning simulation rod through a circle fitting method; determining a femoral intramedullary opening point from the intramedullary positioning simulation rod.

In an alternative implementation, the position of the needle insertion point of the simulated rod in the bone marrow of the femur is determined in the knee replacement, wherein the vertex of the intercondylar notch can be used as the position of the needle insertion point of the simulated rod in the bone marrow, and the position of the needle insertion point can be used as the femoral medullary opening point. In operation, the intramedullary positioning simulation rod and the femoral medullary opening point are visually displayed on the three-dimensional bone model to guide a doctor to open the medullary.

Before osteotomy, in order to ensure that the position of the surgical robot during movement is matched with the position of the knee joint of the patient, the bone needs to be registered, and in a third aspect, the application also provides a bone registration method, which specifically comprises the following steps:

acquiring the spatial position of a preoperative planning point on a skeleton in a three-dimensional model of the knee joint under a three-dimensional model coordinate, and the spatial position of an intraoperative marker point on the solid knee joint skeleton under a world coordinate system;

carrying out coarse registration on the spatial position of the preoperative planning point in the three-dimensional coordinate system and the spatial position of the intraoperative marker point in the world coordinate system to obtain a coarse registration matrix;

acquiring the space position of a marking point set on a target bone of the knee joint of an entity under a world coordinate system; and carrying out fine registration on the space position of the scribing point set under the world coordinate system and the three-dimensional model according to the coarse registration matrix so as to register the world coordinate system to the three-dimensional model coordinate system.

Specifically, the three-dimensional model refers to a bone model of the knee joint. The preoperative planned points are points planned in advance in the three-dimensional model for registration. The intraoperative marker points are points that the physician marks on the surface of the bone during surgery.

Preoperatively, preoperative planning points are determined on the bones in the three-dimensional model of the knee joint. The three-dimensional model may specifically comprise a three-dimensional femoral model and a three-dimensional tibial model. In the knee joint replacement operation process, the patient adopts a supine position, and a doctor can implant fixing nails on each bone of the knee joint of the patient respectively and install tracers on each bone. And then taking the inner side of the knee joint to enter, incising the skin and subcutaneous tissues, entering the joint to fully expose the tibial plateau, and sequentially registering and registering each bone of the knee joint.

In the bone registration process, the optical navigation positioning system acquires the spatial position of a preoperative planning point on a bone in the three-dimensional model of the knee joint under a three-dimensional model coordinate system and the spatial position of an intraoperative marker point on each bone of the solid knee joint under a world coordinate system. For example, 40 bone anchor points may be acquired as intraoperative marker points.

The registration process for a three-dimensional model can be divided into two phases: a coarse registration stage and a fine registration stage. In the coarse registration stage, a preset three-dimensional space point cloud searching mode can be adopted for coarse registration.

For coarse registration, in one embodiment, the coarse registration of the spatial position of the preoperative planning point in the three-dimensional coordinate system with the spatial position of the intraoperative marker point in the world coordinate system includes:

respectively triangulating the spatial position of the preoperative planning point in a three-dimensional coordinate system and the spatial position of the intraoperative marking point in a world coordinate system by a preset three-dimensional space point cloud searching mode to obtain an actual operation triangular sequence corresponding to the intraoperative marking point and a planning triangular sequence corresponding to the preoperative planning point;

correcting preoperative planning points according to the planning triangular sequence in a preset three-dimensional space point cloud searching mode to obtain corrected preoperative planning points;

and carrying out coarse registration on the intraoperative marker points corresponding to the actual operation triangular sequence and the corrected preoperative planning points.

In one embodiment, the triangulating, by a preset three-dimensional spatial point cloud search method, the spatial position of the preoperative planning point in the three-dimensional coordinate system and the spatial position of the intraoperative marking point in the world coordinate system to obtain an actual operation triangle sequence corresponding to the intraoperative marking point and a planning triangle sequence corresponding to the preoperative planning point includes:

forming a triangle by the first three points of the preoperative planning points according to the spatial position of the preoperative planning points under a three-dimensional coordinate system and forming a triangle by the first three points of the intraoperative marking points according to the spatial position of the intraoperative marking points under a world coordinate system in a preset three-dimensional space point cloud searching mode;

respectively selecting two points from the previous points from the fourth point, and forming a triangle with the current point to obtain a real operation triangle sequence corresponding to the intraoperative marker point and a planning triangle sequence corresponding to the preoperative planning point; the triangle composition sequence of the real operation triangle sequence and the planning triangle sequence is the same.

In an embodiment, the modifying the preoperative planning point according to the planning triangle sequence by a preset three-dimensional space point cloud search method to obtain a modified preoperative planning point includes:

determining a second neighborhood space point set of the preoperative planning points on the three-dimensional model by a preset three-dimensional space point cloud searching mode;

screening out a second target point from the second neighborhood space point set;

and correcting the spatial position of the preoperative planning point under the three-dimensional model coordinate to the position corresponding to the second target point according to the planning triangular sequence.

After the coarse registration is completed, a second stage of fine registration is required. In the fine registration stage, preoperative planning is not required, scribing operation can be performed on all bone surfaces of the solid knee joint by using surface calibration equipment such as an operation probe and the like in the operation, and a scribing point set of all the bone surfaces is acquired through the scribing operation. The scribe areas where scribing is required are critical bone areas on the surface of each bone, i.e. areas containing critical bone points.

Specifically, the set of scribe points is composed of points on a plurality of line segments, and may include points in three line segments, for example. And carrying out triangular pairing on the points in the scribing point set, respectively selecting one point in each line segment, forming a triangle by every three points according to the principle that the perimeter of the triangle is the largest, and obtaining a paired triangle sequence according to the triangular pairing mode. The paired triangle sequence includes a plurality of triangles.

Illustratively, the position of a tracer on a surgical probe is tracked through a tracking camera in an optical navigation positioning system, and according to the spatial position of the probe tracer on the surgical probe, which is acquired by the tracking camera, in a world coordinate system in a scribing process, the spatial position of a scribing point set on each bone of the physical knee joint in the world coordinate system is determined to obtain the scribing point set.

In an alternative manner of this embodiment, in the scribing operation, sampling may be performed by the surgical probe at the frequency S, and the sampling operation is performed on the line, so that the whole line segment is subdivided into several point sets.

In the fine registration process, a neighborhood space point set of the scribing point set on the three-dimensional model can be determined firstly, so that the space position of the scribing point set under the coordinate system of the three-dimensional model is corrected according to the neighborhood space point set and the space position of the scribing point set under the world coordinate system, and the corrected space positions of the scribing point set and the scribing point set under the world coordinate system are registered.

In one embodiment, the fine registration of the spatial positions of the set of scribed points in the world coordinate system with the three-dimensional model according to the coarse registration matrix comprises:

reflecting the space position of the scribing point set under the world coordinate system back to the three-dimensional model coordinate system according to the coarse registration matrix to obtain the position of the scribing point set under the three-dimensional model coordinate system;

performing neighborhood space search on the three-dimensional model according to the position of the scribing point set under a three-dimensional model coordinate system to obtain a first neighborhood space point set;

correcting the space position of the scribing point set under a world coordinate system according to the first neighborhood space point set to obtain a line segment point set; and carrying out fine registration on the line segment point set and the three-dimensional model.

Specifically, the coarse registration matrix represents a conversion relation between a world coordinate system obtained by coarse registration and a three-dimensional model coordinate system. According to the rough registration matrix, the space position of the scribing point set under the world coordinate system can be reflected back to the three-dimensional model coordinate system, and therefore the position of the scribing point set under the three-dimensional model coordinate system is obtained. Because the three-dimensional model corresponds to the three-dimensional model coordinate system, the neighborhood space search can be carried out on the three-dimensional model according to the position of the scribing point set under the three-dimensional model coordinate system, and the first neighborhood space point set is obtained. The first neighborhood space point set is a neighborhood space point set corresponding to the scribing point set under the three-dimensional model coordinate system.

In one embodiment, the correcting the spatial position of the set of scribe points in the world coordinate system according to the first neighborhood space point set includes:

carrying out triangular pairing on the points in the scribing point set to obtain a paired triangular sequence; correcting points in the scribing point set according to the first neighborhood space point set and the pairing triangular sequence;

the method specifically comprises the following steps: screening out a first target point from the first neighborhood space point set; and correcting the positions of the points in the scribing point set to the positions corresponding to the first target points according to the pairing triangular sequence.

The first neighborhood space set of points includes a large number of points. The matching triangle sequence comprises a plurality of triangles, each triangle comprises three triangle points, and for the current triangle, a target point corresponding to each triangle point of the current triangle can be screened in the second neighborhood space point set according to the matching triangle sequence to obtain a first target point set. The preset screening strategy is that the triangle formed by the screened three target points and the triangle in the matched triangle sequence are congruent triangles. Because the congruent triangle has extremely small error, the space positions of the three triangular points of the current triangle under the three-dimensional model coordinate can be respectively corrected to the positions of the corresponding target points in the first target point set, and the correction process is repeated, so that the space positions of the scribing point set under the three-dimensional model coordinate are continuously corrected through a large number of triangles in the paired triangular sequence, and the space positions of the scribing point set reflected into the three-dimensional model coordinate system are more accurate.

And then, registering the space positions of the corrected scribing point set and the scribing point set under a world coordinate system through a registration algorithm to obtain a registration result. For example, the registration algorithm may be ICP (Iterative Closest Point algorithm). The registration result can be a transformation relation between a finally obtained world coordinate system and the three-dimensional coordinate, and the precision of the operation in the operation can be improved through the registration result.

In the embodiment, the space positions of the scribing point sets on all bones of the knee joint of the entity under the world coordinate system are obtained through scribing operation, so that the space positions of the scribing point sets under the world coordinate system and the three-dimensional model are subjected to fine registration according to the rough registration matrix.

Target area corresponds to the method for defining a robot motion area of the first aspect, and in a fourth aspect, the present application further provides a method for controlling a surgical robot manipulator, comprising the steps of:

determining the offset of the actuator relative to the current target area according to the current spatial position of the actuator and the spatial position of the current target area of the knee joint in the operation process of the actuator at the tail end of the mechanical arm;

and controlling the mechanical arm according to the offset so as to limit the movement of the actuator in the target area.

Specifically, the surgical robot may be a joint replacement robot (including, but not limited to, a total knee replacement robot and other robots requiring osteotomy), and the robot may mainly include a mechanical arm, and an actuator (in a detachable manner) disposed at an end of the robot, and the actuator may be an osteotomy saw. The main control system of the upper computer can send a bone cutting starting signal to the mechanical arm, and the mechanical arm drives the bone cutting saw at the tail end of the mechanical arm to move after receiving the signal.

The tail end of the mechanical arm and the actual bone cutting region (such as a femur region and a tibia region of a knee joint) can be pre-provided with tracers, each tracer comprises a light sensing small ball capable of emitting infrared rays, the position of the light sensing small ball arranged at the tail end of the mechanical arm is tracked in real time through a binocular infrared camera, the position of the light sensing small ball on the femur region and the position of the light sensing small ball on the tibia region can determine the current spatial position of an actuator at the tail end of the mechanical arm and the current spatial position of each target region, so that the spatial position of the actuator and the spatial position of the current target region can be determined in real time, and further the offset of the actuator relative to the current target region can be determined based on the spatial position of the actuator and the spatial position of the current target region.

The three-dimensional model displays a pre-planned osteotomy sequence, with the current target region being a selected one of a plurality of target regions in response to an operator.

As an optional implementation manner of this embodiment, before the actuator operates, when the robot arm is operated to the knee joint, a position difference between the spatial position of the current target region and the current spatial position of the actuator is determined according to the planned spatial position of the current target region of the knee joint in the three-dimensional model coordinate system and the current spatial position of the actuator; determining the operated displacement of the mechanical arm according to the position difference; and displaying indication adjustment information corresponding to the displacement in the three-dimensional model so that an operator operates the mechanical arm according to the indication adjustment information, and thus, the actuator is adjusted to enable the plane of the actuator to be coplanar with the current target area. It is understood that the plane of the actuator is coplanar with the target area, meaning that the actuator is at the outer edge of the current target area, and the plane of the actuator is aligned substantially in the same plane as the current target area.

The indicated adjustment information corresponding to the amount of displacement may include an adjustment path corresponding to the amount of displacement displayed in an enlarged manner in the target region of the target region, which guides the surgeon to hold the robotic arm and adjust the plane of the actuator to be aligned with the osteotomy plane (the actuator is at the outer edge of the osteotomy plane, and the actuator is substantially coplanar with the osteotomy plane).

In one embodiment, controlling the robotic arm to restrict movement of the actuator within the target region based on the offset comprises:

when the actuator operates, a Cartesian damping control mode taking the virtual springs and the dampers as models is started, and the mechanical arm outputs a feedback force F opposite to the operated direction based on the preset stiffness value C of each virtual spring in the multiple freedom degrees and the offset quantity delta x in the multiple freedom degrees, wherein the F is delta x C, so that the motion of the actuator is limited in the current target area.

The preset stiffness values C in the directions of the respective degrees of freedom are as described above, and are not described herein again.

Target area sixth aspect, the present application further provides a system for defining a robot motion plane, see the schematic structural diagram of a system for defining a robot motion plane shown in fig. 5; the system comprises:

the model establishing module 61 is used for establishing a stiffness-damping model of a virtual spring according to displacement offsets of an actuator at the tail end of a mechanical arm of the robot in the directions of multiple degrees of freedom from an actual position;

a stiffness setting module 62 configured to set stiffness values of each of the virtual springs in a plurality of degrees of freedom to define movement of the actuator on a pre-planned target area. In one embodiment, a direction in which the actuator cuts into the target region is referred to as a depth direction, a direction perpendicular to the depth direction within the target region is referred to as a lateral direction, and a direction perpendicular to the target region is referred to as a vertical direction;

the stiffness setting module 62 is further configured to set, in the direction of translational degree of freedom, a stiffness value of the virtual spring in the depth direction, a stiffness value of the virtual spring in the transverse direction, and a stiffness value of the virtual spring in the vertical direction;

In one embodiment, the stiffness setting module 62 is further configured to set, in the rotational degree of freedom direction, a stiffness value of the virtual spring in a direction of axial rotation with the depth direction as an axis, a stiffness value of the virtual spring in a direction of axial rotation with the lateral direction as an axis, and a stiffness value of the virtual spring in a direction of axial rotation with the vertical direction as an axis;

In one embodiment, the stiffness setting module 62 is further configured to set the first translational preset stiffness threshold to be 0N/m to 500N/m, the second translational preset stiffness threshold to be 4000N/m to 5000N/m, the first rotational preset stiffness threshold to be 0N/m to 20N/m, and the second rotational preset stiffness threshold to be 200N/m to 300N/m.

In one embodiment, a damping setting module 63 is further included for setting damping values of the virtual spring in multiple degrees of freedom.

The model building module 61, the stiffness setting module 62, and the damping setting module 63 may all be located in the robotic arm subsystem 12.

In a sixth aspect, the present application further provides a device for defining a robot movement plane, referring to the schematic structural diagram of the device for defining a robot movement plane shown in fig. 6; the apparatus comprises: at least one processor 71 and at least one memory 72; the memory 72 is for storing one or more program instructions; the processor 71 is configured to execute one or more program instructions to perform any of the steps described above.

In a seventh aspect, the present application further proposes a computer-readable storage medium containing one or more program instructions for performing the steps of any one of the above.

The various methods, steps and logic blocks disclosed in the embodiments of the present invention may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The processor reads the information in the storage medium and completes the steps of the method in combination with the hardware.

The storage medium may be a memory, for example, which may be volatile memory or nonvolatile memory, or which may include both volatile and nonvolatile memory.

The nonvolatile Memory may be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable PROM (EEPROM), or a flash Memory.

The volatile Memory may be a Random Access Memory (RAM) which serves as an external cache. By way of example and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), SLDRAM (SLDRAM), and Direct Rambus RAM (DRRAM).

The storage media described in connection with the embodiments of the invention are intended to comprise, without being limited to, these and any other suitable types of memory.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and they may alternatively be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, or fabricated separately as individual integrated circuit modules, or fabricated as a single integrated circuit module from multiple modules or steps. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for defining a robot motion area, comprising:

setting stiffness values of each of the virtual springs in a plurality of degrees of freedom to define movement of the actuator over a pre-planned target area;

the direction of the actuator cutting into the target area is recorded as a depth direction, the direction in the target area and perpendicular to the depth direction is recorded as a transverse direction, and the direction perpendicular to the target area is recorded as a vertical direction;

setting stiffness values of each of the virtual springs in a plurality of degrees of freedom directions, including:

the stiffness value of the virtual spring in the depth direction and the stiffness value of the virtual spring in the transverse direction are both smaller than or equal to a first translational preset stiffness threshold, and the stiffness value of the virtual spring in the vertical direction is larger than or equal to a second translational preset stiffness threshold;

the first translation preset rigidity threshold value is 0N/m-500N/m;

the second translational preset stiffness threshold value is 4000N/m-5000N/m.

2. The method of defining a robot motion zone of claim 1,

the stiffness value of the virtual spring in the transverse direction is smaller than the stiffness value of the virtual spring in the vertical direction.

3. The method of claim 2, wherein setting stiffness values of each of the virtual springs in a plurality of degrees of freedom comprises:

4. The method of defining a robot motion zone of claim 3,

the first rotational preset stiffness threshold is 0 Nm/rad-20 Nm/rad;

the second rotation preset rigidity threshold value is 200 Nm/rad-300 Nm/rad.

5. The method of defining a robot motion zone of claim 1, further comprising: damping values of the virtual spring in a plurality of degrees of freedom are set.

6. The method of defining a robot motion zone of claim 1,

the target area includes: a femoral anterior resection plane, a femoral anterior oblique resection plane, a femoral posterior condylar resection plane, a femoral posterior oblique resection plane, a femoral distal resection plane, and a tibial resection plane.

7. A system for defining a robot motion field, comprising:

a stiffness setting module for setting stiffness values of each of the virtual springs in a plurality of degrees of freedom to define movement of the actuator on a pre-planned target area;

the rigidity setting module is also used for setting the first translational preset rigidity threshold value to be 0N/m-500N/m and the second translational preset rigidity threshold value to be 4000N/m-5000N/m.

8. The system for defining a robot motion zone of claim 7,

the stiffness value of the virtual spring in the transverse direction is greater than the stiffness value of the virtual spring in the vertical direction.

9. An electronic device, comprising: at least one processor and at least one memory; the memory is to store one or more program instructions; the processor, configured to execute one or more program instructions to perform the method of any of claims 1-6.

10. A computer-readable storage medium having one or more program instructions embodied therein for performing the method of any of claims 1-6.