Method and system for controlling spraying of shotcrete machine mechanical arm based on tunnel wet spraying trajectory

Abstract

The present invention discloses a method for controlling the spraying of a grouting machine robot arm based on a tunnel wet spraying trajectory, which relates to the field of tunnels. The robot arm includes a plurality of joint links connected in sequence, and the end joint link of the robot arm is connected to a spray head, including: S1: obtaining the position and orientation of the nozzle at each point on the trajectory according to the motion posture trajectory; S2: using a preset inverse kinematics model according to the position and orientation of the nozzle, obtaining the rotation angle of each joint link at each point of the trajectory when the grouting machine nozzle performs wet spraying along the motion posture trajectory; S3: controlling the movement of the robot arm according to the rotation angle of each joint link at each point of the trajectory of the nozzle, so as to spray the area to be sprayed. It provides an inverse kinematics model that can be calculated quickly and accurately to obtain the rotation angle of each joint link of the robot arm, and controls the robot arm to spray along a preset trajectory through the rotation angle, so as to realize comprehensive and rapid automatic spraying of the tunnel without manual control.

Description

Technical Field

[0001] The present invention relates to the field of tunnels, and in particular to a method and system for controlling the spraying of a shotcrete machine mechanical arm based on a tunnel wet spraying trajectory. Background Art

[0002] The kinematic modeling of the robot is the basis for controlling the spraying machine's robotic arm to spray along a preset trajectory. It mainly includes two aspects: forward kinematics and inverse kinematics. The purpose of forward kinematics modeling is to calculate the transformation matrix of the robot's end nozzle relative to the first joint link coordinate system based on the known joint variables of the robot arm. This matrix can provide the position and orientation information of the end nozzle relative to the first joint link coordinate system. The purpose of inverse kinematics modeling is to reversely calculate the kinematic parameters of each joint link of the robot arm based on the position and orientation of the end nozzle relative to the first joint link coordinate system.

[0003] For a seven-degree-of-freedom robotic arm (containing multiple rotating and telescopic joint links), using the traditional DH parameter method to establish a forward kinematics model is not only complex, but also increases the difficulty of solving the inverse kinematics. In addition, directly solving the seven-degree-of-freedom robotic arm through inverse kinematics is both difficult and computationally intensive, further increasing the difficulty of controlling the spraying machine robotic arm to spray along a preset trajectory. Therefore, it is urgent to provide an inverse kinematics model that can quickly and accurately calculate the rotation angles of each joint link of the robotic arm, and use this rotation angle to control the spraying machine robotic arm to spray along a preset trajectory, so as to achieve comprehensive, rapid and automatic spraying of tunnels without manual control. Summary of the Invention

[0004] In order to achieve comprehensive, rapid, and automatic spraying of tunnels without manual control, the present invention proposes a method for controlling the spraying of a spraying machine mechanical arm based on a tunnel wet spraying trajectory. The mechanical arm includes a plurality of joint links connected in sequence, and the end joint link of the mechanical arm is connected to a spray head. The tunnel wet spraying trajectory is the motion posture trajectory of the spray head of the spraying machine during the spraying process. The method comprises the following steps:

[0005] S1: Obtain the position and orientation of each point on the trajectory of the nozzle according to the motion posture trajectory;

[0006] S2: Based on the position and orientation of the nozzle, a preset inverse kinematics model is used to obtain the rotation angle of each joint link at each point of the trajectory when the nozzle of the shotcrete machine is wet spraying along the motion trajectory;

[0007] S3: Control the movement of the robotic arm according to the rotation angle of each joint link at each point of the nozzle trajectory to spray the area to be sprayed.

[0008] Furthermore, the steps S2 to S3 also include verification of the rotation angle, specifically:

[0009] S21: According to the rotation angle of each joint link of the nozzle at each point on the trajectory, the position and orientation of the nozzle at each point on the trajectory are obtained using the preset forward kinematics model as the verification position and verification orientation; and the verification position and verification orientation of each point are compared with the position and orientation of the corresponding point in step S1 respectively. If the comparison is consistent, it means that the rotation angle of each joint link corresponding to each point is correctly solved, and enter step S3.

[0010] Furthermore, the joint connecting rod of the robotic arm includes:

[0011] The first rotary joint link, the second rotary joint link, the third rotary joint link, the fourth telescopic joint link, the fifth telescopic joint link, the sixth rotary joint link and the seventh rotary joint link, the fourth telescopic joint link and the fifth telescopic joint link are combined into a movable joint link, wherein the seventh rotary joint link is connected to the nozzle.

[0012] Furthermore, the modeling process of the preset forward kinematics model is:

[0013] Step 1: Set the coordinates of any point in the tunnel wet spraying trajectory to (a, b, c);

[0014] Step 2: According to the coordinates (a, b, c), the homogeneous transformation matrix of the mobile joint link corresponding to the translation operation is:

[0015]

[0016] Step 3: By performing a rotation transformation on the revolute joint link with a rotation angle of θ, the transformation matrices of the revolute joint link corresponding to the rotation operation in the x, y, and z axes are obtained:

[0017]

[0018] Where Rot(x,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the x-axis direction;

[0019]

[0020] Where Rot(y,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the y-axis direction;

[0021]

[0022] Where Rot(z,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the z-axis direction;

[0023] The fourth step is to multiply the transformation matrix in the x-axis, y-axis, and z-axis directions and the homogeneous transformation matrix to obtain the general formula of the transfer transformation matrix of adjacent joint links:

[0024]

[0025] In the formula, i=1, 2, 3, 4, 5, 6; θ i is the rotation angle of the i-th joint link; d i is the offset of the i-th joint link; α i is the preset torsion angle of the i-th joint link; a i is the preset length of the i-th joint link; T i-1,i is the transformation matrix from the i-1th joint link to the i-th joint link, where when i=1, T 0,1 Represents the transformation matrix from the preset base coordinate system established by the robot base to the first joint link;

[0026] The fifth step is to obtain a preset forward kinematics model. The preset forward kinematics model is the product of the general formula of the transfer transformation matrix between each adjacent joint link, and its expression is:

[0027]

[0028] Where, T 12 represents the transformation matrix from the first revolute joint link to the second revolute joint link; T 23 T represents the transformation matrix from the second revolute joint link to the third revolute joint link; 34 T represents the transformation matrix from the third revolving joint link to the moving joint link; 45 represents the transformation matrix from the mobile joint link to the sixth revolving joint link; T 56 represents the transformation matrix from the sixth revolute joint link to the seventh revolute joint link; [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the nozzle; T 06 The transformation matrix from the preset base coordinate system to the nozzle is the preset forward kinematics model.

[0029] Furthermore, the step S2 is specifically as follows:

[0030] In the first step, according to the position and orientation of each point on the motion trajectory of the nozzle obtained in step S1, the transformation matrix from the preset base coordinate system to the nozzle is set to R, which is expressed as:

[0031] In the formula, [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the sprinkler head;

[0032] And by presetting the forward kinematics model, we can get:

[0033] R=T 06 =T 01 ×T 12 ×T 23 ×T 34 ×T 45 ×T 56 ;

[0034] The second step is to fix the third rotating joint link and the fourth telescopic joint link, that is, to preset their parameters, which include rotation angle, offset, preset torsion angle, and preset rod length; obtain the inverse of the general formula of the transfer transformation matrix between each adjacent joint link, and obtain the rotation angle of each joint link through the inverse of the general formula of the transfer transformation matrix between the preset base coordinate system to the nozzle and the adjacent joint links.

[0035] Furthermore, the tunnel is provided with a plurality of arc-shaped steel arches perpendicular to the central axis of the tunnel, and the main model of the tunnel is represented by point cloud data, characterized in that the method for obtaining the wet spraying trajectory of the tunnel comprises the steps of:

[0036] S01: In the main tunnel model, the area between adjacent steel arches is obtained as the area to be sprayed, and the area to be sprayed is vertically divided into two areas of equal width, namely the left spraying area and the right spraying area;

[0037] S02: Obtain the point clouds closest to the cutting surface in the left spray area and the right spray area, and sequentially obtain the distances between the nearest point in the left spray area and the nearest points in the right spray area, obtaining the two closest points with the smallest distance as matching points, and connecting the matching points to obtain the intersection point between the connecting line and the cutting surface;

[0038] S03: Obtain the surface normal vector of the point cloud data of the tunnel surface through the intersection point. The surface normal vector is the inner direction normal vector.

[0039] S04: offsetting each intersection point by a preset distance along the direction of the surface normal vector, obtaining the offset intersection point as the point to be sprayed, and sequentially connecting each point to be sprayed to obtain the tunnel wet spraying trajectory.

[0040] The present invention also proposes a system for controlling the spraying of a shotcrete machine robot arm based on a tunnel wet spraying trajectory. The robot arm includes a plurality of joint links connected in sequence, and the end joint link of the robot arm is connected to a spray head. The system is characterized in that the tunnel wet spraying trajectory is the motion posture trajectory of the spray head of the shotcrete machine during the spraying process. The system includes:

[0041] An acquisition module is used to obtain the position and orientation of each point on the trajectory of the nozzle according to the motion posture trajectory;

[0042] The rotation angle acquisition module is used to obtain the rotation angle of each joint link at each point of the trajectory of the shotcrete machine nozzle when the nozzle is wet spraying along the motion trajectory according to the position and orientation of the nozzle using a preset inverse kinematics model;

[0043] The control module is used to control the movement of the robot arm according to the rotation angle of each joint link at each point of the trajectory of the nozzle, so as to spray the area to be sprayed.

[0044] Furthermore, the system further comprises:

[0045] The verification module is used to obtain the position and orientation of the nozzle at each point in the trajectory as the verification position and verification orientation according to the rotation angle of each joint link of the nozzle at each point in the trajectory using a preset forward kinematics model; and compare the verification position and verification orientation of each point with the position and orientation of the corresponding point in step S1 respectively. If the comparison is consistent, it means that the rotation angle of each joint link corresponding to each point is correctly solved.

[0046] Furthermore, the tunnel is provided with a plurality of curved steel arches perpendicular to the central axis of the tunnel. The main model of the tunnel is represented by point cloud data, and is characterized in that the acquisition of the wet spraying trajectory of the tunnel includes:

[0047] The cutting module is used to obtain the area between adjacent steel arches in the tunnel main model as the area to be sprayed, and vertically cut the area to be sprayed into two areas of equal width, namely the left spraying area and the right spraying area;

[0048] The intersection point acquisition module is used to obtain the point cloud closest to the cutting surface in the left spray area and the right spray area, and sequentially obtain the distance between the nearest point in the left spray area and the nearest points in the right spray area, so as to obtain the two closest points with the smallest distance as matching points, and connect the matching points to obtain the intersection point between the connecting line and the cutting surface;

[0049] A normal vector acquisition module is used to obtain the surface normal vector of the point cloud data of the tunnel surface through the intersection point. The surface normal vector is the inner direction normal vector;

[0050] The trajectory acquisition module is used to offset each intersection point by a preset distance along the direction of the surface normal vector, and the offset intersection point is obtained as the point to be sprayed. The points to be sprayed are connected in sequence to obtain the tunnel wet spraying trajectory.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] (1) The present invention obtains the position and orientation of each point on the trajectory of the nozzle through the motion posture trajectory, and uses a preset inverse kinematics model according to the position and orientation of the nozzle to obtain the rotation angle of each joint link at each point of the trajectory when the nozzle of the shotcrete machine performs wet spraying along the motion posture trajectory, and controls the movement of the robot arm according to the rotation angle of each joint link at each point of the trajectory of the nozzle to spray the area to be sprayed, thereby realizing comprehensive and rapid spraying of the tunnel without manual control;

[0053] (2) In the process of modeling the preset forward kinematics model, the present invention establishes a preset base coordinate system at the base of the manipulator, and from the preset base coordinate system to the first joint link, the first joint link to the second joint link, and so on, until the sixth joint link to the seventh joint link. This is different from the traditional DH parameter method which only sets a coordinate system on each joint link. The present invention starts with translation and rotation from the base coordinate system established at the base of the manipulator (after establishing a base coordinate system at the base of the manipulator, directly translate the base coordinate system and move it to the center position of the next joint. If the next joint is a translation joint, continue to translate the coordinate system; if the next joint is a rotation joint, rotate the coordinate system, and so on to obtain the final coordinate system of each joint). This method is clearer than the traditional DH parameter method, avoids joint ambiguity, and reduces the difficulty of solving inverse kinematics.

[0054] (3) In order to solve the problem of high difficulty and large amount of calculation in directly solving the seven-degree-of-freedom manipulator through inverse kinematics, the present invention fixes the third rotating joint link and the fourth telescopic joint link in the modeling process of the preset inverse kinematics model, that is, adopts the fixed joint angle method to solve the inverse kinematics model to solve the analytical solution of the remaining five joints. This method greatly reduces the computational difficulty and the amount of calculation, thereby greatly improving the spraying speed of the manipulator;

[0055] (4) The present invention verifies the analytical solution obtained by the preset inverse kinematics model through the preset forward kinematics model, which improves the accuracy of the analytical solution and further improves the spraying accuracy of the spraying machine robot arm during the spraying process. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A flow chart of a method for controlling the spraying of a shotcrete machine robot arm based on a tunnel wet spraying trajectory;

[0057] Figure 2 This is a system module diagram for controlling the spraying of the spraying machine robot arm based on the tunnel wet spraying trajectory;

[0058] Figure 3 This is the joint link diagram of the shotcrete machine robot arm;

[0059] Figure 4 This is a projection diagram of the robotic arm. DETAILED DESCRIPTION

[0060] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0061] Example 1

[0062] In order to provide an inverse kinematics model that can quickly and accurately calculate the rotation angle of each joint link of the robot arm, and control the spraying machine robot arm to spray along the preset trajectory through the rotation angle, so as to achieve comprehensive and rapid automatic spraying of the tunnel without manual control, such as Figure 1 As shown, the present invention proposes a method for controlling the spraying of a shotcrete machine robot arm based on a tunnel wet spraying trajectory, wherein the robot arm includes a plurality of joint links connected in sequence, and the end joint link of the robot arm is connected to a spray head. The tunnel wet spraying trajectory is the motion posture trajectory of the spray head of the shotcrete machine during the spraying process. The method comprises the following steps:

[0063] S1: Obtain the position and orientation of each point on the trajectory of the nozzle according to the motion posture trajectory;

[0064] like Figure 3 As shown, the joint connecting rod of the robotic arm includes:

[0065] The first rotating joint link (joint 1), the second rotating joint link (joint 2), the third rotating joint link (joint 3), the fourth telescopic joint link (joint 4), the fifth telescopic joint link (joint 5), the sixth rotating joint link (joint 6) and the seventh rotating joint link (joint 7), the fourth telescopic joint link and the fifth telescopic joint link are combined into a movable joint link, wherein the seventh rotating joint link is connected to the nozzle.

[0066] The shotcrete machine used in the present invention is a seven-degree-of-freedom robotic arm, and has both rotational and telescopic joints. Using the traditional DH parameter method to establish a forward kinematics model is not only more complicated, but also increases the difficulty of solving inverse kinematics. Unlike the traditional parameter method, the present invention establishes a base coordinate system at the base of the robotic arm to make the parameters clearer than the traditional DH method, and can also avoid joint ambiguity.

[0067] In the modeling process of the preset forward kinematics model, the present invention establishes a preset base coordinate system on the base of the robotic arm, from the preset base coordinate system to the first joint link, the first joint link to the second joint link, and so on, until the sixth joint link to the seventh joint link. This is different from the traditional DH parameter method which only sets the coordinate system on each joint link. The present invention starts with translation and rotation from the base coordinate system established on the base of the robotic arm (after establishing a base coordinate system on the base of the robotic arm, directly translate the base coordinate system and move it to the center position of the next joint. If the next joint is a translation joint, continue to translate the coordinate system; if the next joint is a rotation joint, rotate the coordinate system, and so on to obtain the final coordinate system of each joint). This method is clearer than the traditional DH parameter method, avoids joint ambiguity, and reduces the difficulty of solving inverse kinematics.

[0068] S2: Based on the position and orientation of the nozzle, a preset inverse kinematics model is used to obtain the rotation angle of each joint link at each point of the trajectory when the nozzle of the shotcrete machine is wet spraying along the motion trajectory;

[0069] The steps S2 to S3 also include verification of the rotation angle, specifically:

[0070] S21: According to the rotation angle of each joint link of the nozzle at each point on the trajectory, the position and orientation of the nozzle at each point on the trajectory are obtained using the preset forward kinematics model as the verification position and verification orientation; and the verification position and verification orientation of each point are compared with the position and orientation of the corresponding point in step S1 respectively. If the comparison is consistent, it means that the rotation angle of each joint link corresponding to each point is correctly solved, and enter step S3.

[0071] The modeling process of the preset forward kinematics model is:

[0072] Step 1: Set the coordinates of any point in the tunnel wet spraying trajectory to (a, b, c);

[0073] Step 2: According to the coordinates (a, b, c), the homogeneous transformation matrix of the mobile joint link corresponding to the translation operation is:

[0074]

[0075] Step 3: By performing a rotation transformation on the revolute joint link with a rotation angle of θ, the transformation matrices of the revolute joint link corresponding to the rotation operation in the x, y, and z axes are obtained:

[0076]

[0077] Where Rot(x,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the x-axis direction;

[0078]

[0079] Where Rot(y,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the y-axis direction;

[0080]

[0081] Where Rot(z,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the z-axis direction;

[0082] The fourth step is to multiply the transformation matrix in the x-axis, y-axis, and z-axis directions and the homogeneous transformation matrix to obtain the general formula of the transfer transformation matrix of adjacent joint links:

[0083]

[0084] In the formula, i=1, 2, 3, 4, 5, 6; θ i is the rotation angle of the i-th joint link; d i is the offset of the i-th joint link; α i is the preset torsion angle of the i-th joint link; a i is the preset length of the i-th joint link; T i-1,i is the transformation matrix from the i-1th joint link to the i-th joint link, where when i=1, T 0,1 Represents the transformation matrix from the preset base coordinate system established by the robot base to the first joint link;

[0085] The joint link parameters in this embodiment are shown in the following table (since the fourth telescopic joint link and the fifth telescopic joint link are combined into one movable joint link, there are six joint links in total. The value range of d4 in the table is 1982 to 6582 mm):

[0086]

[0087] Through the data in the joint link parameter table and the general formula of the transfer transformation matrix of the adjacent joint links in the preset forward kinematics model, we can obtain:

[0088]

[0089]

[0090]

[0091] The fifth step is to obtain a preset forward kinematics model. The preset forward kinematics model is the product of the general formula of the transfer transformation matrix between each adjacent joint link, and its expression is:

[0092]

[0093] Where, T 12 represents the transformation matrix from the first revolute joint link to the second revolute joint link; T 23 T represents the transformation matrix from the second revolute joint link to the third revolute joint link; 34 T represents the transformation matrix from the third revolving joint link to the moving joint link; 45 represents the transformation matrix from the mobile joint link to the sixth revolving joint link; T 56 represents the transformation matrix from the sixth revolute joint link to the seventh revolute joint link; [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the nozzle; T 06 The transformation matrix from the preset base coordinate system to the nozzle is the preset forward kinematics model.

[0094] In this embodiment, after substituting the data, we get:

[0095] n x =sinθ6(cosθ1cosθ2sinθ3-cosθ1sinθ2cosθ3)-sinθ1sinθ5cosθ6-cosθ1cosθ5cosθ6(sinθ2sinθ3+cosθ2cosθ3);

[0096] n y =cosθ1sinθ5cosθ6+sinθ1cosθ5cosθ6(sinθ2sinθ3+cosθ2cosθ3)+sinθ1sinθ6(cosθ2sinθ3-sinθ2cosθ3);

[0097] n z =cosθ5cosθ6(cosθ2sinθ3-sinθ2cosθ3)-sinθ6(sinθ2sinθ3+cosθ2cosθ3);

[0098] o x =sinθ1sinθ5sinθ6+cosθ1cosθ5sinθ6(sinθ2sinθ3+cosθ2cosθ3)+cosθ1sinθ6(cosθ2sinθ3-sinθ2cosθ3);

[0099] o y =sinθ1cosθ6(cosθ2sinθ3-sinθ2cosθ3)-cosθ1sinθ5sinθ6+sinθ1cosθ5sinθ6(sinθ2sinθ3+cosθ2cosθ3);

[0100] o z =cosθ5sinθ6(sinθ2cosθ3-cosθ2sinθ3)-cosθ6(sinθ2sinθ3+cosθ2cosθ3);

[0101] a x =-sinθ1cosθ5-cosθ1sinθ5(sinθ2sinθ3+cosθ2cosθ3);a y =cosθ1cosθ5-sinθ1sinθ5(sinθ2sinθ3+cosθ2cosθ3);

[0102] a z =sinθ5(sinθ2cosθ3-cosθ2sinθ3);

[0103] P x=3219cosθ1cosθ2-426sinθ1-325sinθ1cosθ5+cosθ1(d4-990)(cosθ2sinθ3-sinθ2cosθ3)-325cosθ1sinθ5(sinθ2sinθ3+cosθ2cosθ3);

[0104] P y =3219sinθ1cosθ2+426cosθ1+325cosθ1cosθ5+sinθ1(d4-990)(cosθ2sinθ3-sinθ2cosθ3)-325sinθ1sinθ5(sinθ2sinθ3+cosθ2cosθ3);

[0105] P z =(990-d4)(sinθ2sinθ3+cosθ2cosθ3)-3219sinθ2-426sinθ1-325sinθ5(cosθ2sinθ3-sinθ2cosθ3);

[0106] The step S2 is specifically as follows:

[0107] In the first step, according to the position and orientation of each point on the motion trajectory of the nozzle obtained in step S1, the transformation matrix from the preset base coordinate system to the nozzle is set to R, which is expressed as:

[0108] In the formula, [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the sprinkler head;

[0109] And by presetting the forward kinematics model, we can get:

[0110] R=T 06 =T 01 ×T 12 ×T 23 ×T 34 ×T 45 ×T 56 (Formula 8);

[0111] The second step is to fix the third rotating joint link and the fourth telescopic joint link, that is, to preset their parameters, which include rotation angle, offset, preset torsion angle, and preset rod length; obtain the inverse of the general formula of the transfer transformation matrix between each adjacent joint link, and obtain the rotation angle of each joint link through the inverse of the general formula of the transfer transformation matrix between the preset base coordinate system to the nozzle and the adjacent joint links.

[0112] In order to solve the problem that it is difficult and computationally intensive to directly solve a seven-degree-of-freedom robotic arm through inverse kinematics, the present invention fixes the third rotational joint link and the fourth telescopic joint link during the modeling process of the preset inverse kinematics model, that is, the fixed joint angle method is used to solve the inverse kinematics model to obtain the analytical solution of the remaining five joint links. This method greatly reduces the computational difficulty and the computational complexity, thereby greatly improving the spraying speed of the robotic arm.

[0113] Based on the data in the joint link parameter table, the calculation process of the joint link rotation angle is shown as follows:

[0114] By presetting the general formula of the transfer transformation matrix of adjacent joint links in the forward kinematics model, we can obtain:

[0115]

[0116] Multiply the left side of equation 7 by T 01 The inverse of , we get (Equation 10):

[0117]

[0118] Multiply the right side of equation 7 by T 01 The inverse of , we get (Equation 11):

[0119]

[0120] Where C 23 represents cos(θ2+θ3), S 23 represents sin(θ2+θ3), C2 represents cos(θ2), C5 represents cos(θ5), C6 represents cos(θ6), S5 represents sin(θ5), and S6 represents sin(θ6);

[0121] 1) Solve for θ1

[0122] The elements in the second row and fourth column of (Equation 10) and (Equation 11) are equal:

[0123] P y cosθ1-P xsinθ1=325cosθ5+426 (Equation 12);

[0124] The elements in the second row and third column of (Equation 10) and (Equation 11) are equal:

[0125] a y cosθ1-a x sinθ1=cosθ5 (Equation 13);

[0126] Substituting (Equation 13) into (Equation 12) and eliminating cos(θ5) yields the trigonometric equations for θ1, which can be solved for the two values ​​of θ1:

[0127]

[0128]

[0129] Where,

[0130] 2) Solve for θ5

[0131] According to (Equation 13) and the solved θ1, it can be calculated that:

[0132]

[0133] The range of θ5 is [0, 2π], while the range of arccosine is [0, π], so there are two other solutions for θ5:

[0134]

[0135] 3) Solve for θ6

[0136] Since the elements in the 2nd row and 1st column of (Equation 10) and (Equation 11) are equal, the elements in the 2nd row and 2nd column are equal, and sinθ5 is eliminated, we have

[0137]

[0138] Considering the value range of θ6, the solution for θ6 is:

[0139]

[0140] 4) Solve for θ2+θ3. In the following solution, C1 represents cos(θ1), C6 represents cos(θ6), S1 represents sin(θ1), and Sx represents sin(θ6).

[0141] Multiply both sides of (Equation 10) by T 06 The inverse of , we get:

[0142]

[0143] Multiply both sides of (Equation 11) by T 06 The inverse of , we get:

[0144]

[0145] Where C 23 represents cos(θ2+θ3), S 23 represents sin(θ2+θ3), C2 represents cos(θ2), C5 represents cos(θ5), and S2 represents sin(θ2);

[0146] The elements in the first row and second column of (Equation 21) and (Equation 22) are equal, the elements in the third row and second column are equal, and cos(θ5) is eliminated to obtain:

[0147]

[0148] 5) Solve for θ3

[0149] The second joint link, the third joint link, and the fourth joint link are coupled to each other. It is difficult to establish a suitable equivalent relationship in the above matrix elements for stripping solution. Therefore, the robot arm is projected onto the x1o1z1 plane of a joint link (such as Figure 4 Calculation is performed as shown).

[0150] The position relationship of the five joint links in a joint coordinate system is expressed by (Equation 10), that is, Figure 4 The horizontal and vertical coordinates of point o5 corresponding to x5 in the x1o1z1 coordinate system are:

[0151] Where c1 represents cos(θ1) and s1 represents sin(θ1);

[0152] Figure 4 The unit direction vector of o1o3 can be represented by the z5 direction, which is the third column element in the matrix (Equation 22), and then the distance d from o1 to o1o3 can be calculated. oD The two solutions are:

[0153]

[0154] In addition, d can be created in triangle o1o3D oD The relationship with θ3 is as follows:

[0155]

[0156] From (Equation 25) and (Equation 26), we can calculate θ3 as:

[0157]

[0158] 6) Solve for θ2

[0159] According to the solved values ​​of θ2+θ3 and θ3, θ2 is obtained as:

[0160]

[0161] 7) Solve d4

[0162] Since the elements in the 3rd row and 4th column of (Equation 21) and (Equation 22) are equal, we can find that d4 has

[0163]

[0164] At this point, the analytical solutions for each joint are completed. Multiple sets of solutions can be obtained by combining different joints (for each transformation matrix, 16 sets of solutions can be obtained through the preset inverse kinematics model). These 16 sets of solutions are input into the preset forward kinematics model respectively. If the 16 transformation matrices calculated are completely consistent with the transformation matrix input when solving the analytical solution, it means that the analytical solution is correct, thereby verifying the correctness of the preset inverse kinematics model.

[0165] Solving inverse kinematics for a robot is a multi-solution problem. To use inverse kinematics to drive the joint linkages of a robotic arm, one must select the solution that best reflects the actual motion trajectory of the robotic arm from multiple sets of solutions. A common approach to this inverse solution selection problem is to apply the shortest path principle, which optimizes by moving smaller joints more and larger ones less.

[0166] Based on this, we add screening conditions to the 16 groups of solutions solved by the preset inverse kinematics model, including minimizing the changes in the joint variables between the current solution and the previous group of solutions; giving priority to changing the joint variables of the joints closer to the end nozzle, that is, following the principle of "moving more small joints and fewer large joints"; the incremental directions of rotating joints such as pitch and yaw, and moving joints such as telescoping, etc. are kept as consistent as possible. The above screening conditions can be used to select the best set of solutions as the joint variables that need to be input when the robotic arm moves. In this embodiment, the weight coefficient method is proposed to simplify the multi-solution optimization problem into a single-objective optimization problem, and the evaluation function of the i-th group of inverse solutions is:

[0167] Where K is a preset constant; the number 6 is the number of joint links; w j is the weight coefficient of the j-th joint link; i is the group solution number; the weight coefficient of the large joint should be greater than the weight coefficient of the small joint, that is, w1>w2>w3>w4>w5>w6; θ j,i is the rotation angle of the jth joint link in the i-th solution; θ j,i-1When i-1=0, it indicates the rotation angle of the base corresponding to the j-th joint link; by comparing the evaluation function values ​​corresponding to each group of solutions, the group of solutions corresponding to the largest evaluation function value is the optimal solution, and is used as the joint variable required to be input when the robotic arm moves.

[0168] S3: Control the movement of the robotic arm according to the rotation angle of each joint link at each point of the nozzle trajectory to spray the area to be sprayed.

[0169] The present invention obtains the position and orientation of the nozzle at each point on the trajectory through the motion posture trajectory, and uses a preset inverse kinematics model according to the position and orientation of the nozzle to obtain the rotation angle of each joint link at each point on the trajectory when the spraying machine nozzle performs wet spraying along the motion posture trajectory, and controls the movement of the robotic arm according to the rotation angle of each joint link at each point on the trajectory of the nozzle to spray the area to be sprayed, thereby realizing rapid spraying of the tunnel surface without manual control.

[0170] The tunnel is provided with a plurality of arc-shaped steel arches perpendicular to the central axis of the tunnel. The main model of the tunnel is represented by point cloud data. The method for obtaining the wet spraying trajectory of the tunnel comprises the steps of:

[0171] S01: In the main tunnel model, the area between adjacent steel arches is obtained as the area to be sprayed, and the area to be sprayed is vertically divided into two areas of equal width, namely the left spraying area and the right spraying area;

[0172] The arc-shaped steel arches are arranged in the tunnel in sequence and at equal intervals.

[0173] In step S01, the area to be sprayed is vertically cut into two areas of equal width, specifically:

[0174] The point cloud slicing technology is used to vertically cut the area to be sprayed into two areas of equal width using a plane parallel to the X=0 plane.

[0175] Specifically, the area to be sprayed is vertically cut into two areas of equal width in a direction perpendicular to the central axis of the tunnel.

[0176] S02: Obtain the point clouds closest to the cutting surface in the left spray area and the right spray area, and sequentially obtain the distances between the nearest point in the left spray area and the nearest points in the right spray area, obtaining the two closest points with the smallest distance as matching points, and connecting the matching points to obtain the intersection point between the connecting line and the cutting surface;

[0177] S03: Obtain the surface normal vector of the point cloud data of the tunnel surface through the intersection point. The surface normal vector is the inner direction normal vector.

[0178] S04: offsetting each intersection point by a preset distance along the direction of the surface normal vector, obtaining the offset intersection point as the point to be sprayed, and sequentially connecting each point to be sprayed to obtain the tunnel wet spraying trajectory.

[0179] The present invention obtains the point cloud closest to the cutting surface in the left spraying area and the right spraying area, and sequentially obtains the distances between the nearest point in the left spraying area and the nearest points in the right spraying area, so as to obtain the two nearest points with the smallest distance as matching points, thereby obtaining the points to be sprayed that form the tunnel wet spraying trajectory, and sequentially connects the points to be sprayed to obtain the complete tunnel wet spraying trajectory, which improves the accuracy of the tunnel wet spraying trajectory.

[0180] In this embodiment, an S-shaped trajectory is used for spraying. Considering the actual orientation of the spraying vehicle and boom, with the front of the boom facing the outside of the tunnel and the range of motion of the 1-joint link being ±180°, the tunnel is divided into two halves for trajectory planning. Starting from the tunnel bottom, the spray gun tip moves back and forth along the tunnel wet spraying trajectory, layer by layer, to achieve continuous, comprehensive, and automatic rapid spraying of the tunnel.

[0181] In actual shotcrete support operations, shotcrete trajectory planning is an extremely important issue. Only by accurately and continuously planning the tunnel wet spraying trajectory can the preset inverse kinematics model of the present invention be used to control the robotic arm to accurately use the tunnel wet spraying trajectory as the moving spraying trajectory to carry out comprehensive, continuous and rapid automatic spraying of the tunnel.

[0182] Example 2

[0183] like Figure 2 As shown, the present invention also proposes a system for controlling the spraying of a shotcrete machine robot arm based on a tunnel wet spraying trajectory. The robot arm includes a plurality of joint links connected in sequence, and the end joint link of the robot arm is connected to a spray head. The tunnel wet spraying trajectory is the motion posture trajectory of the spray head of the shotcrete machine during the spraying process. The system includes:

[0184] An acquisition module is used to obtain the position and orientation of each point on the trajectory of the nozzle according to the motion posture trajectory;

[0185] The rotation angle acquisition module is used to obtain the rotation angle of each joint link at each point of the trajectory of the shotcrete machine nozzle when the nozzle is wet spraying along the motion trajectory according to the position and orientation of the nozzle using a preset inverse kinematics model;

[0186] The control module is used to control the movement of the robot arm according to the rotation angle of each joint link at each point of the trajectory of the nozzle, so as to spray the area to be sprayed.

[0187] The system further comprises:

[0188] The verification module is used to obtain the position and orientation of the nozzle at each point in the trajectory as the verification position and verification orientation according to the rotation angle of each joint link of the nozzle at each point in the trajectory using a preset forward kinematics model; and compare the verification position and verification orientation of each point with the position and orientation of the corresponding point in step S1 respectively. If the comparison is consistent, it means that the rotation angle of each joint link corresponding to each point is correctly solved.

[0189] The present invention verifies the analytical solution obtained by the preset inverse kinematics model through the preset forward kinematics model, which improves the accuracy of the analytical solution and thus further improves the spraying accuracy of the spraying machine robot arm during the spraying process.

[0190] The tunnel is provided with a plurality of curved steel arches perpendicular to the central axis of the tunnel. The main model of the tunnel is represented by point cloud data, which is characterized in that the acquisition of the wet spraying trajectory of the tunnel includes:

[0191] The cutting module is used to obtain the area between adjacent steel arches in the tunnel main model as the area to be sprayed, and vertically cut the area to be sprayed into two areas of equal width, namely the left spraying area and the right spraying area;

[0192] The intersection point acquisition module is used to obtain the point cloud closest to the cutting surface in the left spray area and the right spray area, and sequentially obtain the distance between the nearest point in the left spray area and the nearest points in the right spray area, so as to obtain the two closest points with the smallest distance as matching points, and connect the matching points to obtain the intersection point between the connecting line and the cutting surface;

[0193] A normal vector acquisition module is used to obtain the surface normal vector of the point cloud data of the tunnel surface through the intersection point. The surface normal vector is the inner direction normal vector;

[0194] The trajectory acquisition module is used to offset each intersection point by a preset distance along the direction of the surface normal vector, and the offset intersection point is obtained as the point to be sprayed. The points to be sprayed are connected in sequence to obtain the tunnel wet spraying trajectory.

[0195] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0196] In addition, in the present invention, descriptions such as "first," "second," and "one" are for descriptive purposes only and should not be understood to indicate or imply their relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0197] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0198] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A method for controlling the spraying of a shotcrete machine robot arm based on a tunnel wet spraying trajectory, wherein the robot arm comprises a plurality of joint links connected in sequence, and the end joint link of the robot arm is connected to a spray head, characterized in that: The tunnel wet spraying trajectory is the motion posture trajectory of the spraying head of the spraying machine during the spraying process; the joint connecting rod of the robotic arm includes: a first rotating joint connecting rod, a second rotating joint connecting rod, a third rotating joint connecting rod, a fourth telescopic joint connecting rod, a fifth telescopic joint connecting rod, a sixth rotating joint connecting rod and a seventh rotating joint connecting rod connected in sequence, the fourth telescopic joint connecting rod and the fifth telescopic joint connecting rod are combined into a movable joint connecting rod, wherein the seventh rotating joint connecting rod is connected to the spraying head; the method comprises the steps of: S1: Obtain the position and orientation of each point on the trajectory of the nozzle according to the motion posture trajectory; S2: Based on the position and orientation of the nozzle, a preset inverse kinematics model is used to obtain the rotation angle of each joint link at each point of the trajectory when the nozzle of the shotcrete machine is wet spraying along the motion trajectory; The steps S2 to S3 also include verification of the rotation angle, specifically: S21: according to the rotation angle of each joint link of the nozzle at each point on the trajectory, a preset forward kinematics model is used to obtain the position and orientation of the nozzle at each point on the trajectory as a verification position and a verification orientation; The verified position and verified orientation of each point are compared with the position and orientation of the corresponding point in step S1. If the comparison is consistent, it means that the rotation angle of each joint link corresponding to each point is solved correctly, and the process goes to step S3; The modeling process of the preset forward kinematics model is: Step 1: Set the coordinates of any point in the tunnel wet spraying trajectory to (a, b, c); Step 2: According to the coordinates (a, b, c), the homogeneous transformation matrix of the mobile joint link corresponding to the translation operation is: Step 3: By performing a rotation transformation on the revolute joint link with a rotation angle of θ, the transformation matrices of the revolute joint link corresponding to the rotation operation in the x, y, and z axes are obtained: Where Rot(x,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the x-axis direction; Where Rot(y,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the y-axis direction; Where Rot(z,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the z-axis direction; The fourth step is to multiply the transformation matrix in the x-axis, y-axis, and z-axis directions and the homogeneous transformation matrix to obtain the general formula of the transfer transformation matrix of adjacent joint links: In the formula, i=1, 2, 3, 4, 5, 6; θ i is the rotation angle of the i-th joint link; d i is the offset of the i-th joint link; α i is the preset torsion angle of the i-th joint link; a i is the preset rod length of the i-th joint link; T i-1,i is the transformation matrix from the i-1th joint link to the i-th joint link, where when i=1, T 0,1 Represents the transformation matrix from the preset base coordinate system established by the robot base to the first joint link; The fifth step is to obtain a preset forward kinematics model. The preset forward kinematics model is the product of the general formula of the transfer transformation matrix between each adjacent joint link, and its expression is: Where, T 12 represents the transformation matrix from the first revolute joint link to the second revolute joint link; T 23 T represents the transformation matrix from the second revolute joint link to the third revolute joint link; 34 T represents the transformation matrix from the third revolving joint link to the moving joint link; 45 represents the transformation matrix from the mobile joint link to the sixth revolving joint link; T 56 represents the transformation matrix from the sixth revolute joint link to the seventh revolute joint link; [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the nozzle; T 06 The transformation matrix from the preset base coordinate system to the nozzle is the preset forward kinematics model; The step S2 is specifically as follows: In the first step, according to the position and orientation of each point on the motion trajectory of the nozzle obtained in step S1, the transformation matrix from the preset base coordinate system to the nozzle is set to R, which is expressed as: In the formula, [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the sprinkler head; And by presetting the forward kinematics model, we can get: R=T 06 =T 01 ×T 12 ×T 23 ×T 34 ×T 45 ×T 56 ; The second step is to fix the third rotating joint link and the fourth telescopic joint link, that is, to preset their parameters, which include rotation angle, offset, preset torsion angle, and preset rod length; obtain the inverse of the general formula of the transfer transformation matrix between each adjacent joint link, and obtain the rotation angle of each joint link through the inverse of the general formula of the transfer transformation matrix between the preset base coordinate system and the nozzle; S3: Control the movement of the robotic arm according to the rotation angle of each joint link at each point of the nozzle trajectory to spray the area to be sprayed.

2. According to the method of claim 1, a method for controlling the spraying of a spraying machine robot arm based on a tunnel wet spraying trajectory, wherein the tunnel is provided with a plurality of curved steel arches perpendicular to the central axis of the tunnel, and the main tunnel model is represented by point cloud data, characterized in that: The method for obtaining the tunnel wet spraying trajectory comprises the following steps: S01: In the main tunnel model, the area between adjacent steel arches is obtained as the area to be sprayed, and the area to be sprayed is vertically divided into two areas of equal width, namely the left spraying area and the right spraying area; S02: Obtain the point clouds closest to the cutting surface in the left spray area and the right spray area, and sequentially obtain the distances between the nearest point in the left spray area and the nearest points in the right spray area, obtaining the two closest points with the smallest distance as matching points, and connecting the matching points to obtain the intersection point between the connecting line and the cutting surface; S03: Obtain the surface normal vector of the point cloud data of the tunnel surface through the intersection point. The surface normal vector is the inner direction normal vector. S04: offsetting each intersection point by a preset distance along the direction of the surface normal vector, obtaining the offset intersection point as the point to be sprayed, and sequentially connecting each point to be sprayed to obtain the tunnel wet spraying trajectory.

3. A system for controlling the spraying of a spraying machine robot arm based on a tunnel wet spraying trajectory, wherein the robot arm comprises a plurality of joint links connected in sequence, and the end joint link of the robot arm is connected to a spray head, characterized in that: The tunnel wet spraying trajectory is the motion posture trajectory of the spraying head of the spraying machine during the spraying process; the joint link of the robotic arm includes: a first rotating joint link, a second rotating joint link, a third rotating joint link, a fourth telescopic joint link, a fifth telescopic joint link, a sixth rotating joint link and a seventh rotating joint link connected in sequence, the fourth telescopic joint link and the fifth telescopic joint link are combined into a mobile joint link, wherein the seventh rotating joint link is connected to the spraying head; the system includes: An acquisition module is used to obtain the position and orientation of each point on the trajectory of the nozzle according to the motion posture trajectory; The rotation angle acquisition module is used to obtain the rotation angle of each joint link at each point of the trajectory of the shotcrete machine nozzle when the nozzle is wet spraying along the motion trajectory according to the position and orientation of the nozzle using a preset inverse kinematics model; The system further comprises: The verification module is used to obtain the position and orientation of the nozzle at each point on the trajectory as the verification position and verification orientation based on the rotation angle of each joint link at each point on the trajectory of the nozzle using a preset forward kinematics model; and the verification position and verification orientation of each point are sequentially compared with the position and orientation of the corresponding point in step S1. If the comparison is consistent, it means that the rotation angle of each joint link corresponding to each point is correctly solved; The modeling process of the preset forward kinematics model is: Step 1: Set the coordinates of any point in the tunnel wet spraying trajectory to (a, b, c); Step 2: According to the coordinates (a, b, c), the homogeneous transformation matrix of the mobile joint link corresponding to the translation operation is: Step 3: By performing a rotation transformation on the revolute joint link with a rotation angle of θ, the transformation matrices of the revolute joint link corresponding to the rotation operation in the x, y, and z axes are obtained: Where Rot(x,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the x-axis direction; Where Rot(y,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the y-axis direction; Where Rot(z,θ) is the transformation matrix of the rotation joint link corresponding to the rotation operation in the z-axis direction; The fourth step is to multiply the transformation matrix in the x-axis, y-axis, and z-axis directions and the homogeneous transformation matrix to obtain the general formula of the transfer transformation matrix of adjacent joint links: In the formula, i=1, 2, 3, 4, 5, 6; θ i is the rotation angle of the i-th joint link; d i is the offset of the i-th joint link; α i is the preset torsion angle of the i-th joint link; a i is the preset length of the i-th joint link; T i-1,i is the transformation matrix from the i-1th joint link to the i-th joint link, where when i=1, T 0,1 Represents the transformation matrix from the preset base coordinate system established by the robot base to the first joint link; The fifth step is to obtain a preset forward kinematics model. The preset forward kinematics model is the product of the general formula of the transfer transformation matrix between each adjacent joint link, and its expression is: Where, T 12 represents the transformation matrix from the first revolute joint link to the second revolute joint link; T 23 T represents the transformation matrix from the second revolute joint link to the third revolute joint link; 34 T represents the transformation matrix from the third revolving joint link to the moving joint link; 45 represents the transformation matrix from the mobile joint link to the sixth revolving joint link; T 56 represents the transformation matrix from the sixth revolute joint link to the seventh revolute joint link; [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the nozzle; T 06 The transformation matrix from the preset base coordinate system to the nozzle is the preset forward kinematics model; The rotation angle acquisition module is specifically used for: In the first step, according to the position and orientation of each point on the motion trajectory of the nozzle obtained in step S1, the transformation matrix from the preset base coordinate system to the nozzle is set to R, which is expressed as: In the formula, [P x ,P y ,P z ] T Indicates the position of the nozzle; [n x ,n y ,n z ] T ,[o x ,o y ,o z ] T ,[a x ,a y ,a z ] T Indicates the direction of the sprinkler head; And by presetting the forward kinematics model, we can get: R=T 06 =T 01 ×T 12 ×T 23 ×T 34 ×T 45 ×T 56 ; The second step is to fix the third rotating joint link and the fourth telescopic joint link, that is, to preset their parameters, which include rotation angle, offset, preset torsion angle, and preset rod length; obtain the inverse of the general formula of the transfer transformation matrix between each adjacent joint link, and obtain the rotation angle of each joint link through the inverse of the general formula of the transfer transformation matrix between the preset base coordinate system and the nozzle; The control module is used to control the movement of the robot arm according to the rotation angle of each joint link at each point of the trajectory of the nozzle, so as to spray the area to be sprayed.

4. A system for controlling spraying of a shotcrete machine arm based on a tunnel wet spraying trajectory according to claim 3, wherein the tunnel is provided with a plurality of curved steel arches perpendicular to the central axis of the tunnel, and the main tunnel model is represented by point cloud data, characterized in that: The acquisition of the tunnel wet spraying trajectory includes: The cutting module is used to obtain the area between adjacent steel arches in the tunnel main model as the area to be sprayed, and vertically cut the area to be sprayed into two areas of equal width, namely the left spraying area and the right spraying area; The intersection point acquisition module is used to obtain the point cloud closest to the cutting surface in the left spray area and the right spray area, and sequentially obtain the distance between the nearest point in the left spray area and the nearest points in the right spray area, so as to obtain the two closest points with the smallest distance as matching points, and connect the matching points to obtain the intersection point between the connecting line and the cutting surface; A normal vector acquisition module is used to obtain the surface normal vector of the point cloud data of the tunnel surface through the intersection point. The surface normal vector is the inner direction normal vector; The trajectory acquisition module is used to offset each intersection point by a preset distance along the direction of the surface normal vector, and the offset intersection point is obtained as the point to be sprayed. The points to be sprayed are connected in sequence to obtain the tunnel wet spraying trajectory.

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