A Parallel Constraint Projection Positioning Method for Preoperative Positioning of Two Arms of a Surgical Robot

Abstract

This invention proposes a parallel constraint projection positioning method for preoperative positioning of the two arms of a surgical robot, comprising the following steps: Step 1, solving the forward kinematics of the front-end robotic arm based on the DH method to determine the initial posture of the passive positioning device during preoperative positioning; Step 2, constructing the projection mapping relationship between the passive positioning device and the end effector fixed point by combining the characteristics of the parallel constraint structure. This method solves the existing problem of aligning the two arms of a surgical robot with the operating table, enabling the two arms to accurately position themselves to the lesion puncture point along the desired posture during preoperative positioning, ensuring that the surgeon can perform safe and efficient surgical operations on the lesion area within the collaborative space planned by the arm motion.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a method for preoperative positioning of the two arms of a surgical robot using parallel constraint projection. Background Technology

[0002] Most existing minimally invasive medical devices require a lot of time and effort to adjust their position during preoperative setup; the assembly process requires repeated positioning to ensure that the robotic arm and the operating table are in the most ideal position and that the surgical procedure can be performed within the optimal collaborative space. Summary of the Invention

[0003] This application proposes a parallel constraint projection positioning method for the preoperative positioning of the two arms of a surgical robot to solve the problem of alignment and positioning between the two arms of the surgical robot and the operating table. This method enables the two arms of the surgical robot to be accurately positioned at the lesion puncture point along the desired posture during preoperative positioning, ensuring that the surgeon can perform safe and efficient surgical operations on the lesion area within the collaborative space planned by the movement of the two arms.

[0004] To achieve the above objectives, this application proposes a parallel constraint projection positioning method for preoperative positioning of a surgical robot's dual arms. The surgical robot includes a base, a central column mounted on the base, a first rotating structure mounted on the central column, a boom connected to the first rotating structure, a second rotating structure connected to the boom, and a passive positioning device connected to the second rotating structure. A first controllable arm device and a second controllable arm device are respectively connected to the passive positioning device. The end positions of both the first and second controllable arm devices are designated as fixed points, which are positions with a fixed distance constraint from the passive positioning device. The base, central column, first rotating structure, boom, and second rotating structure are designated as the front-end robotic arm, and the end position of the front-end robotic arm refers to the end of the second rotating structure. The method includes the following steps:

[0005] Step 1: Solve the forward kinematics of the front-end robotic arm based on the DH method to determine the initial posture of the passive positioning device during preoperative positioning;

[0006] Step 2: Based on the characteristics of the parallel constraint structure, construct the projection mapping relationship between the passive positioning device and the end fixed point.

[0007] In some embodiments, step 1 includes the following steps:

[0008] Step 101: Describe the rigid body pose using the homogeneous transformation method;

[0009] Step 102: Input the initial parameter values ​​of the front-end robotic arm and construct the coordinate system of the front-end robotic arm;

[0010] Step 103: Construct the DH parameter table for the front-end robotic arm;

[0011] Step 104: Solve the positive kinematic mapping relationship from the base to the end of the front robotic arm.

[0012] In some embodiments, step 2 includes the following steps:

[0013] Step 201: Preoperative positioning and layout of parallel constraint projection space;

[0014] Step 202: Based on the parallel constraint projection positioning algorithm of fixed points, construct the projection plane coordinate system, and perform fixed point positioning analysis based on the parameter changes of the passive positioning device. That is, according to the position offset parameters of the passive positioning device links under different conditions, calculate the end position of each link of the passive positioning device, and finally solve the position of the fixed point and the cooperative target space of its traversal motion. The passive positioning device includes N links, which are denoted as the first link, the second link, ..., the Nth link. The first link is close to the front end of the robotic arm. The first link, the second link, ..., the (N-1)th link all have position offset parameters. The deflection angle of each link in the first link, the second link, ..., the (N-1)th link relative to its own initial position is denoted as the position offset parameter of the link.

[0015] The beneficial effect of the solution in this application is that the above-mentioned parallel constraint projection positioning method for the preoperative positioning of the surgical robot's two arms can solve the problem of alignment and positioning between the existing surgical robot's two arms and the operating table, so that the surgical robot's two arms can be accurately positioned to the lesion puncture point along the desired posture during preoperative positioning, ensuring that the doctor can perform safe and efficient surgical operations on the lesion area in the collaborative space of the two arm movement planning. Attached Figure Description

[0016] Figure 1 A schematic diagram of the structure of a surgical robot in the prior art is shown.

[0017] Figure 2 A top view is shown in the embodiment where the movable link of the passive positioning device is N=3.

[0018] Figure 3 The embodiment shows the angle deflection design when the movable link of the passive positioning device is N=3, where (a) is the angle deflection design of the first joint and (b) is the angle deflection design of the third joint.

[0019] Figure 4 The simplified geometric structure of the passive positioning device in the embodiment is shown when the movable link is N=2.

[0020] Figure 5This diagram illustrates the target collaborative space where the surgical robot's two arms traverse and interact with each other at fixed points, aligning with the surgical incision location on the lesion area.

[0021] Reference numerals: 1-base, 2-central column, 3-first rotating structure, 4-lifting rod, 5-second rotating structure, 6-fixed point, 7-passive positioning device, 8-first controllable arm device, 9-second controllable arm device. Detailed Implementation

[0022] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0023] In the description of this application, it should be understood that the terms "first," "second," etc., are used to distinguish similar objects, rather than to describe or indicate a specific order or sequence. The terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] Currently, the arms of surgical robots inherently possess multi-joint and modular characteristics. For example... Figure 1 As shown, the surgical robot includes:

[0025] Base 1: Includes surgical platform device for positioning and transportation, patient surgical platform electronics and connector panel;

[0026] Central column 2: The central column 2 moves the hanger 4 up or down;

[0027] Boom 4: Boom 4 is an adjustable rotatable support structure for the robotic arm (controllable arm device);

[0028] First rotating structure 3 and second rotating structure 5: rotating structures of the machine arm group connecting the boom 4;

[0029] Fixed point 6: A position that is subject to a fixed distance constraint from the passive positioning device 7;

[0030] Passive positioning device 7: During preoperative positioning, the fixed point at the end of the traction controllable arm device is positioned to the puncture point feature area.

[0031] First controllable arm device 8 and second controllable arm device 9: Patient surgical platform arm device, which can operate the instrument to move to the desired position.

[0032] Specifically, the base 1, the central column 2, the first rotating structure 3, the hanging rod 4, and the second rotating structure 5 are referred to as the front-end robotic arm, and the end position of the front-end robotic arm refers to the end of the second rotating structure 5.

[0033] In view of the structure of the surgical robot described above, this application proposes a method for preoperative positioning of the two arms of the surgical robot using parallel constraint projection, comprising the following steps:

[0034] Step 1: Solve the forward kinematics of the front-end robotic arm based on the DH method to determine the initial posture of the passive positioning device 7 during preoperative positioning.

[0035] The core idea of ​​this step is to use the DH method to perform kinematic modeling on the front-end robotic arm of the surgical robot, calculate the spatial transformation and position transfer relationships between each joint and the end effector, and obtain the end-effector output information of the front-end robotic arm as the initial posture of the passive positioning device 7. The specific process includes the following steps:

[0036] Step 101: Use the homogeneous transformation method to describe the pose of the rigid body.

[0037] Using the homogeneous transformation method to describe the pose of a rigid body allows the kinematic relationships between links to be transformed into mathematical calculations. In a Cartesian coordinate system {A}, the position vector of any point P in space is described by a 3×1 vector. A P is:

[0038]

[0039] In the formula: P x This represents the x-component of point P along the x-axis; P y This represents the component of point P along the y-axis; P z This represents the component of point P along the z-axis. A In P, A represents the coordinate system {A}.

[0040] To represent the orientation of any rigid body B in three-dimensional space, a coordinate system {B} is established, corresponding to the unit direction vector x. B y B 、z B The relationship with coordinate system {A} is as follows:

[0041]

[0042] In the formula: In this context, A represents coordinate system {A}, and B represents coordinate system {B}.

[0043] because A x B , A y B , A zB Both are unit vectors and are perpendicular to each other, {r ij} represents the column element corresponding to the unit vector, i,j=1,2,3, such as A x B Corresponding to {r i1 The column vector of} A y B Corresponding to {r i2 The column vector of} A z B Corresponding to {r i3 The column vectors of}, so for the rotation matrix There is a relation:

[0044]

[0045] in, T is the transpose of the matrix, and |·| represents the determinant.

[0046] use This indicates the position of the origin of coordinate system {B} within coordinate system {A}. Let {B} represent the orientation of the coordinate axes in coordinate system {A}. Then:

[0047]

[0048] in, Indicates the position of an object. Indicates the posture of an object.

[0049] The general formula for representing rigid body pose using homogeneous matrices is:

[0050]

[0051] Step 102: Input the initial parameter values ​​of the front-end robotic arm and construct the coordinate system of the front-end robotic arm.

[0052] DH parametric coordinate system construction guidelines: See Figure 1 A base coordinate system is constructed with the center of the bottom end of the surgical robot's base 1 as the origin:

[0053] a) Using the vertically upward direction as the z-axis, translate along the z-axis by a distance d1 to determine the first coordinate system;

[0054] b) Rotate counterclockwise around the z-axis by an angle θ2, then clockwise by 90° to determine the second coordinate system.

[0055] c) Rotate 90° clockwise around the x-axis and translate a distance d3 along the z-axis to determine the third coordinate system;

[0056] d) Rotate counterclockwise around the x-axis by 90°, then rotate counterclockwise around the z-axis by θ4, then rotate counterclockwise around the z-axis by 90° to determine the fourth coordinate system.

[0057] Step 103: Construct the DH parameter table for the front-end robotic arm.

[0058] Table 1. DH Parameter Table for the Front-End Robotic Arm

[0059] Serial Number <![CDATA[α i-1 ]]> <![CDATA[a i-1 ]]> <![CDATA[θ i ]]> <![CDATA[d i ]]> 1 0 0 0 <![CDATA[d1]]> 2 0 0 <![CDATA[θ2-90°]]> 0 3 -90° 0 0 <![CDATA[d3]]> 4 90° 0 <![CDATA[θ4+90°]]> 0

[0060] Where, for any link i, a i Indicates the length of the connecting rod, α i d represents the linkage angle. i θ represents the offset distance of the link. i The joint angle of the link is represented by the DH parameter in Table 1, which is determined by combining the actual measured value. The parameters are set as follows: d1∈[1950,2375], d3∈[850,1199], θ2∈[0,81.5°], θ4∈[0,287.2°].

[0061] Step 104: Solve the positive kinematic mapping relationship from base 1 to the end of the front robotic arm.

[0062] Here, we choose the surgical robot base 1 as the origin to construct a base coordinate system. Using the concept of DH parameter transformation, we construct a positive kinematic mapping relationship from base 1 to the end effector of the robotic arm. Therefore, under the DH transformation concept, if the transformation of adjacent links can be expressed relative to coordinate system {i-1}, then coordinate system {i} represents the transformation matrix. The general formula for link transformation is:

[0063]

[0064] Among them, T z,d Relative to parameter d i Transformation, T z,θ Represents relative to parameter θ i Transformation, T x,a Relative to parameter a i Transformation, T x,α Represents relative to parameter α i The transformation.

[0065] Based on the DH parameter table, the transition matrices for each connected joint are obtained:

[0066]

[0067]

[0068]

[0069]

[0070] The mathematical expression of the homogeneous transformation matrix from base 1 to the end effector of the robotic arm is as follows:

[0071]

[0072] Equation (7-1) can be decoupled as follows:

[0073]

[0074] Among them, s k =sinθ k c k =cosθ k k = 2, 4, s 2+4 =sin(θ2+θ4), c 2+4 =cos(θ2+θ4).

[0075] n represents the normal vector, n = o × a;

[0076] o represents the orientation vector, the direction of the line connecting the end of the front robotic arm and the actuator gripper;

[0077] 'a' represents the proximity vector, which is the direction in which the end of the robotic arm approaches the object from the actuator.

[0078] p represents the position vector, the origin of the coordinate system at the end of the robotic arm.

[0079]

[0080]

[0081]

[0082] Here, det(·) represents the determinant of the matrix. express The matrix consisting of the elements in the 2nd and 3rd rows / columns, express The matrix consisting of the elements in the 1st and 3rd rows / columns, express A matrix consisting of the elements in the first and second rows / columns.

[0083] According to the homogeneous matrix representation of expression (5), the rotation matrix of the object position at the end of the front robotic arm relative to base 1 is:

[0084]

[0085] Relative to base 1, the position of the object at the end of the front robotic arm is:

[0086]

[0087] Using equations (8-1) to (8-3), the attitude direction vector can be calculated. for:

[0088]

[0089] Based on the above forward kinematics solution, the homogeneous transformation expression (7-1) from the base 1 to the end of the front robotic arm is obtained. Using equations (10) and (11), the initial center position vector of the passive positioning device 7 can be calculated. and attitude direction vector That is, the initial posture of the passive positioning device 7 is determined during preoperative positioning.

[0090] Step 2: Based on the characteristics of the parallel constraint structure, construct the projection mapping relationship between the passive positioning device 7 and the end fixed point 6.

[0091] During the surgery, the first controllable arm device 8 and the second controllable arm device 9 need to be operated in a small space. In order to ensure the accuracy of the operation, the passive positioning device 7 needs to be properly positioned in space during the preoperative positioning. The specific solution steps are as follows:

[0092] Step 201: Preoperative positioning and layout of parallel constraint projection space.

[0093] See Figure 2 By adjusting the linkage size and joint range of motion of the passive positioning device 7, the cross-sectional motion range of the fixed point 6 can be calculated, so that the fixed point coincides with the corresponding puncture point. To achieve this goal, the centers of the first controllable arm device 8 and the second controllable arm device 9 are set to be located exactly on the vertical symmetry plane of the surgical robot. According to the doctor's operating posture and placement habits, the puncture point should be placed in the overlapping and cooperative area of ​​the fixed point motion at the end of the first controllable arm device 8 and the second controllable arm device 9—the cooperative working area.

[0094] Define the inertial coordinate system {O0} and the body coordinate system {O b The parameter descriptions in the Cartesian coordinate system are shown in Table 2.

[0095] Table 2 Description of parameters for passive positioning devices

[0096]

[0097] It is worth noting that due to the limitations of wire transmission, the second link b and the virtual fixed link (the fourth link) d only perform translational motion, where d is the projection of the distance from the end joint of the third link to the fixed point in the horizontal plane.

[0098] Step 202: Based on the parallel constraint projection positioning algorithm of fixed points, construct the projection plane coordinate system, and perform fixed point positioning analysis based on the parameter changes of the passive positioning device 7. That is, according to the position offset parameters of the links of the passive positioning device 7 under different conditions, calculate the end position of each link of the passive positioning device 7, and finally solve the position of the fixed point and the cooperative target space of its traversal motion. The passive positioning device 7 includes N links, which are respectively denoted as the first link, the second link, ..., the Nth link. The first link is close to the front end of the robotic arm. The first link, the second link, ..., the (N-1)th link all have position offset parameters. The deflection angle of each link in the first link, the second link, ..., the (N-1)th link relative to its own initial position is recorded as the position offset parameter of the link.

[0099] The construction of the projection plane coordinate system includes the following rules for determining the coordinates of fixed points on the projection plane: (e.g.) Figure 2 As shown, let point O be the origin, the horizontal direction to the right be the x-axis, and the vertical direction upward be the y-axis. Under this coordinate system xOy, it is not difficult to determine the position of each joint point under different conditions, and the position of the fixed point (RCM) is also relatively fixed.

[0100] In step 202, a fixed-point positioning analysis is performed based on the parameter changes of the passive positioning device 7: Without loss of generality, parameters are selected... d1 = 1950mm, d3 = 850mm. Combining DH parameter tables 1 and 2, the initial position of the passive positioning device 7 can be obtained. According to the description in table 2, the length unit in the following analysis is uniformly defined as mm.

[0101] See Figure 3 Note the parallel structural features of the passive positioning device 7: regardless of the deflection angle of the first link (or the second link) relative to its initial position. What is the value at which the geometry of the second (and third) link remains parallel throughout? The following is a step-by-step analysis:

[0102] 2.1) Main components of passive positioning device 7: Scenario analysis of link number N=3

[0103] against Figure 2 The following analysis is given regarding the parallel constraint projection spatial positioning layout design:

[0104] i) Case 1: Initial state

[0105] Relative to the initial position of the passive positioning device 7 The fixed point position of the xOy projection plane of the fourth link is determined, as shown in Table 3.1.

[0106] Table 3.1 Case study of fixed point determination process

[0107]

[0108] in, This represents the absolute offset of the second link relative to the first link on the x-axis. This represents the absolute offset of the second link relative to the first link on the y-axis, and the corresponding numerical calculation is as follows:

[0109]

[0110] here, This represents the absolute offset of the fourth link relative to the third link on the x-axis. This represents the absolute offset of the fourth link relative to the third link on the y-axis, and the corresponding numerical calculation is as follows:

[0111]

[0112] Therefore, relative to the initial position The position of the end of the fourth link is the relative position of the fixed point.

[0113]

[0114] Therefore, relative to base 1, calculating the position of the end of the fourth link is the absolute position of the fixed point:

[0115]

[0116] ii) Case 2:

[0117] Relative to the initial position The fixed point position of the xOy projection plane of the fourth link is determined, as shown in Table 3.2.

[0118] Table 3.2 Case study of fixed point determination process

[0119]

[0120] in, This represents the absolute offset of the second link relative to the first link on the x-axis. This represents the absolute offset of the second link relative to the first link on the y-axis, and the corresponding numerical calculation is as follows:

[0121]

[0122] here, This represents the absolute offset of the fourth link relative to the third link on the x-axis. This represents the absolute offset of the fourth link relative to the third link on the y-axis. The corresponding numerical calculation is carried out through the following analysis.

[0123] See Figure 3 An angular deflection occurs at the end of the second link. Analyzing the geometric relationship of spatial projection, this relationship is actually equivalent to the angle that occurs at the end of the first link. In the case of deflection, the geometric constraints of spatial projection in both cases have mapping similarity equivalence, and the vectors... Solving for the projected coordinates in the xOy direction is an example of applying this geometric similarity equivalence. The specific steps are as follows:

[0124] In triangle AB′C′, applying the triangle cosine theorem, the length of the hypotenuse of an obtuse triangle is... The conclusion is

[0125]

[0126] Using the law of sines,

[0127]

[0128] Find the hypotenuse of the triangle and The included angle:

[0129]

[0130] The results of the sorting are related to the deflection angle. Key relevant angles:

[0131]

[0132] So, relative to the initial position The position of the end of the fourth link is the relative position of the fixed point.

[0133]

[0134] set up Therefore, relative to base 1, calculating the position of the end of the fourth link is the absolute position of the fixed point:

[0135]

[0136] iii) Situation 3:

[0137] Relative to the initial position The fixed point position of the xOy projection plane of the fourth link is determined, as shown in Table 3.3.

[0138] Table 3.3 Case study of fixed point determination process

[0139]

[0140] in, This represents the absolute offset of the fourth link relative to the third link on the x-axis. This represents the absolute offset of the fourth link relative to the third link on the y-axis, and the corresponding numerical calculation is as follows:

[0141]

[0142] here, R represents the position of the second link relative to its initial position. s0,3 Absolute offset on the x-axis R represents the position of the second link relative to its initial position. s0,3 The absolute offset on the y-axis is calculated through the following analysis.

[0143] See Figure 3 An angular deflection occurs at the end of the first link. Analyzing the geometric relationships of spatial projection: In ΔAB′C′, applying the triangle cosine theorem, the length of the hypotenuse of the obtuse triangle... (C′ new (The symbol indicating the distinction of C′), such as Figure 3 Therefore, we can conclude that:

[0144]

[0145] Using the law of sines,

[0146]

[0147] Find the hypotenuse of the triangle and The included angle:

[0148]

[0149] The analysis yielded results related to the deflection angle. Key relevant angles:

[0150]

[0151] So, relative to the initial position The position of the end of the fourth link is the relative position of the fixed point.

[0152]

[0153] set up Therefore, relative to base 1, calculating the position of the end of the fourth link is the absolute position of the fixed point:

[0154]

[0155] iv) Situation 4:

[0156] Relative to the initial position The fixed point position of the xOy projection plane of the fourth link is determined, as shown in Table 3.4.

[0157] Table 3.4 Case study of fixed point determination process

[0158]

[0159] in, R represents the position of the second link relative to its initial position. s0,4 Absolute offset on the x-axis R represents the position of the second link relative to its initial position. s0,4 Absolute offset on the y-axis This represents the absolute offset of the fourth link relative to the second link on the x-axis. This represents the absolute offset of the fourth link relative to the second link on the y-axis. The corresponding numerical calculation is carried out through the following analysis.

[0160] See Figure 3 An angular deflection occurs at the end of the first link. An angular deflection occurs at the end of the second link. In this context, we analyze the geometric relationships of spatial projection.

[0161] 1) Utilizing situation iii) Analysis

[0162] An angular deflection occurs at the end of the first link in case iii). Referring to expressions (19) to (22), calculate the position of the end of the second link:

[0163]

[0164] in, (C′ 1，4 The symbol for C′ is different from the C′ mentioned above. new ),

[0165]

[0166] 2) Utilizing the situation ii) Analysis

[0167] An angular deflection occurs at the end of the second link in case ii). Geometric similarity and equivalence of link space projections, vectors The projection of the xOy direction is the coordinate value we are looking for.

[0168] Referring to expressions (14) to (17), the position of the end of the fourth link is calculated:

[0169]

[0170] in, C′ 2，4 The symbol for C′ is different from the C′ mentioned above. new C′ 1，4 ),

[0171]

[0172] So, relative to the initial position The position of the end of the fourth link is the relative position of the fixed point.

[0173]

[0174] set up Therefore, relative to base 1, calculating the position of the end of the fourth link is the absolute position of the fixed point:

[0175]

[0176] 2.2) Main components of passive positioning device 7: Scenario analysis of link number N=2

[0177] The analysis in 2.1) above is for the case where the number of movable links is N=3. So how to achieve projection positioning mapping based on fixed points when the number of movable links is reduced to N=2? Here, we analyze the case where the number of movable links is N=2, that is, when c=0 and a and b are constants.

[0178] Relative to the initial position The fixed point position of the xOy projection plane of the fourth link (excluding the third link) is determined, as shown in Table 3.5.

[0179] Table 3.5 Case Study of Fixed Point Determination when N=2

[0180]

[0181] i) See Figure 4 ,when When, the position at point D is represented as the position at point C (C x C y ), along the direction The projection position, as described in i) of case 2.1), is easily calculated (C). x C y The value of ) is:

[0182]

[0183] This indicates relative to the initial position O (initial position) Position D:

[0184]

[0185] Relative to base 1, calculating the position of the end of the 4th link is the absolute position of the fixed point:

[0186]

[0187] ii) When When, the position at D′ is represented as the position at C′ (C′ x ,C′ y ), along the direction The projection position, as described in iii) of case 2.1), is easily calculated (C′). x ,C′ y The value of ) is:

[0188]

[0189] Among them, (C′ 1，2 The symbol for C′ is different from the C′ mentioned above. new C′ 1，4 C′ 2，4 ).

[0190]

[0191] Using the law of sines,

[0192]

[0193] Find the hypotenuse of the triangle and The included angle:

[0194]

[0195] The analysis yielded results related to the deflection angle. Key relevant angles:

[0196]

[0197] This indicates relative to the initial position O (initial position) The position of D′ at point D:

[0198]

[0199] set up Indicates the position of D′ relative to O:

[0200] It can be calculated that:

[0201]

[0202] set up Therefore, relative to base 1, calculating the position of the end of the fourth link is the absolute position of the fixed point:

[0203]

[0204] From the above results, it can be concluded that for the cases where the moving links of the passive positioning device 7 are N=2 and N=3, the above geometric calculation steps can be applied sequentially to iteratively solve for more complex cases, such as N=4, 5, L. Therefore, theoretically, for any number of moving links N=K, the position of the fixed point D(D′) obtained by parallel constraint projection positioning mapping can always be solved analytically.

[0205] See Figure 5 Based on the modular structural design of the surgical robot, the solution of its overall kinematics is decoupled. To establish the complete forward kinematics of the front-end robotic arm, 1) the mapping relationship from the base to the end effector of the front-end robotic arm is planned using the DH method; 2) the position of the fixed point of the surgical robot is obtained by using the parallel constraint projection relationship of the passive positioning device; 3) the motion range of the preoperative positioning is planned. Therefore, by combining the motion positioning mapping relationship of each component of the surgical robot, the surgical incision position of the puncture point of the surgical robot is determined. Simulation verification ensures that the surgery is performed in the collaborative space of the motion planning of the controllable arm device of the surgical robot, and the doctor can perform precise, safe and efficient surgical operations on the lesion area.

[0206] In response to the demand for precision surgical manipulation, this patent application proposes a parallel constraint projection positioning method for the preoperative positioning of the two arms of a surgical robot. This method not only decouples the solution of the overall kinematics of the surgical robot through modular design, but also determines the planar projection position information of the fixed points of the surgical robot using the DH method and spatial geometric parallel constraints. Ultimately, it derives the spatial positional relationship from the base to the fixed points and the target area for the collaboration of the two arms, thus solving the problem of difficulty in aligning and positioning the two arms of a surgical robot with the surgical table. The parallel constraint projection positioning method for the preoperative positioning of the two arms of the surgical robot involved in this application enables the two arms of the surgical robot to be accurately positioned to the lesion puncture point along the desired posture during preoperative positioning, ensuring that the surgeon can perform safe and efficient surgical operations on the lesion area within the collaborative space planned by the arm movements.

[0207] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and concept of this application, should be included within the scope of protection of this application.

Claims

1. A method for preoperative positioning and parallel constraint projection of a surgical robot's dual arms, wherein the surgical robot includes a base, a central column mounted on the base, a first rotating structure mounted on the central column, a boom connected to the first rotating structure, a second rotating structure connected to the boom, a passive positioning device connected to the second rotating structure, a first controllable arm device and a second controllable arm device respectively connected to the passive positioning device, wherein the end positions of both the first and second controllable arm devices are designated as fixed points, which are positions with a fixed distance constraint from the passive positioning device, and the base, central column, first rotating structure, boom, and second rotating structure are designated as the front-end robotic arm, wherein the end position of the front-end robotic arm refers to the end of the second rotating structure; characterized in that: Includes the following steps: Step 1: Solve the forward kinematics of the front-end robotic arm based on the DH method to determine the initial posture of the passive positioning device during preoperative positioning; Step 2: Based on the characteristics of the parallel constraint structure, construct the projection mapping relationship between the passive positioning device and the end fixed point; Step 1 includes the following steps: Step 101: Describe the rigid body pose using the homogeneous transformation method; Step 102: Input the initial parameter values ​​of the front-end robotic arm and construct the coordinate system of the front-end robotic arm; Step 103: Construct the DH parameter table for the front-end robotic arm; Step 104: Solve the positive kinematic mapping relationship from the base to the end of the front robotic arm; Step 2 includes the following steps: Step 201: Preoperative positioning and layout of parallel constraint projection space; Step 202: Based on the parallel constraint projection positioning algorithm of fixed points, construct the projection plane coordinate system, and perform fixed point positioning analysis based on the parameter changes of the passive positioning device. That is, according to the position offset parameters of the passive positioning device links under different conditions, calculate the end position of each link of the passive positioning device, and finally solve the position of the fixed point and the cooperative target space of its traversal motion. The passive positioning device includes N links, which are denoted as the first link, the second link, ..., the Nth link. The first link is close to the front end of the robotic arm. The first link, the second link, ..., the (N-1)th link all have position offset parameters. The deflection angle of each link in the first link, the second link, ..., the (N-1)th link relative to its own initial position is denoted as the position offset parameter of the link.

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