Shield segment automatic assembling method based on line laser sensor

Abstract

The present application relates to the field of measurement positioning, tunnel segment automatic assembly technology field, especially to a kind of shield segment pose measurement and automatic assembly method based on line laser sensor, when robot picks up segment and sends segment to rough assembly position, each line laser can just irradiate to the edge of assembled segment and segment to be assembled, wherein three line lasers irradiate segment arc side, and the random intersection point of segment arc side edge of segment to be assembled is respectively set as A, B, C;And the random intersection point of assembled segment arc side edge is respectively set as A', B', C';Two line lasers irradiate segment straight side, and the random intersection point of segment straight side edge of segment to be assembled is respectively set as D, E;And the random intersection point of assembled segment straight side edge is respectively set as D', E';Line laser sensor used in the present application has the characteristics of high measurement accuracy, is not affected by construction illumination etc.

Description

Technical Field

[0001] This invention relates to the field of measurement and positioning, and the field of automated assembly technology of tunnel segments, and particularly to a method for measuring and automating the pose of shield tunnel segments based on a line laser sensor. Background Technology

[0002] With rapid economic development and urbanization, underground railway systems have gradually become an effective and convenient mode of transportation to alleviate urban traffic congestion. Currently, underground tunnel excavation mainly employs the shield tunneling method. The segment assembly machine is an important subsystem of the shield tunneling machine, primarily responsible for assembling the segments during shield construction. Segment assembly mainly consists of three processes: segment grabbing, segment delivery, and segment assembly. Ultimately, the precast reinforced concrete segments are assembled into a ring to provide support for the tunnel.

[0003] In current tunnel boring machine (TBM) construction, automated tunnel segment assembly is mainly achieved by marking the segments. Industrial cameras capture the markings, and image processing algorithms extract features from the markings to determine the segment's position, enabling automated segment grabbing and assembly. This method requires pre-marking at specific locations on the segments, and errors in the marking position can affect the assembly accuracy, making it unsuitable for the high-precision segment assembly required in tunnel construction. Summary of the Invention

[0004] In view of this, the present invention aims to provide an automated assembly method for shield tunnel segments based on line laser sensors, so as to realize tunnel construction that requires high-precision assembly of tunnel segments during shield tunneling.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The automated assembly method for tunnel boring machine segments based on line laser sensors includes the following steps:

[0007] Step 1: Installation and deployment of the line laser;

[0008] Step 2: Establishing the coordinate system;

[0009] Step 3: Algorithm for Automated Assembly Position Measurement of Tunnel Segments;

[0010] In step one, five line laser sensors are used to measure the pose of the tube segments and the assembly error of the tube segments. The line laser sensors are all fixedly mounted on the robot's gripping plate. When the robot grips the tube segment and delivers it to the rough assembly position, each line laser can just illuminate the edges of the assembled tube segment and the tube segment to be assembled. Three line lasers illuminate the arc-shaped side of the tube segment, and the random intersection points with the edge of the tube segment to be assembled are set as A, B, and C, respectively; the random intersection points with the arc-shaped side edge of the assembled tube segment are set as A', B', and C', respectively; two line lasers illuminate the straight edge of the tube segment, and the random intersection points with the straight edge edge of the tube segment to be assembled are set as D and E, respectively; the random intersection points with the straight edge edge of the assembled tube segment are set as D' and E', respectively.

[0011] In step two, a coordinate system {seg1} for the segment to be assembled and a coordinate system {seg2} for the assembled segment are established with A and A' as origins. In the {seg1} coordinate system, the x-axis is perpendicular to surface ABC, and the y-axis is along line AB. In the {seg2} coordinate system, the x-axis is perpendicular to surface A'B'C', and the y-axis is along line A'B'. Line laser 1 illuminates A and A', line laser 2 illuminates B and B', and line laser 3 illuminates C and C'. The coordinate systems of the three line lasers are {s1}, {s2}, and {s3}, respectively. Let the coordinate system of the robotic arm end effector be {t}, and the robot base coordinate system be {b}.

[0012] As a further aspect of the present invention: the algorithm control flow in step three includes the following steps:

[0013] A. Leveling: Leveling refers to adjusting the pose of the tube segment to be assembled so that the axial arc side of the tube segment to be assembled is parallel to that of the already assembled tube segment, i.e., surface ABC is parallel to surface A'B'C'. Line lasers s1, s2 and s3 are used to measure the pose of the tube segment to be assembled and the already assembled tube segment in the robot's base coordinate system. Keeping the position of the tube segment to be assembled unchanged, the pose of the already assembled tube segment is used as the desired pose. The desired pose when the axial arc side of the tube segment to be assembled is adjusted to be parallel to that of the already assembled tube segment is solved. Then, the desired pose of the end effector of the robot is solved after leveling. Combining the robot's inverse kinematics, the motion bias required to reach each degree of freedom of the desired pose is solved. Based on the bias, the robot is controlled to adjust the tube segment to be assembled so that its axial side is parallel to that of the already assembled tube segment.

[0014] B. Translation along the positive x-axis of {seg1}: After leveling, the robot needs to translate the tube segment to be assembled along the positive x-axis of the coordinate system {seg1} of the tube segment to be assembled to reduce the gap between the tube segment to be assembled and the axial arc side of the assembled tube segment. The gap between the tube segment to be assembled and the axial arc side of the assembled tube segment is calculated by measuring with line lasers s1, s2, and s3. It is then determined whether the gap is within the allowable error range. If it is within the allowable error range, the translation movement is stopped; otherwise, the translation movement continues until the error is within the allowable range.

[0015] C. Adjust the rotation of the tube segment around the x-axis of {seg1}: After the tube segment is translated along the positive x-axis of {seg1} so that the gap between the tube segment to be assembled and the axial arc-shaped side of the assembled tube segment is within the allowable error range and the translation stops, the robotic arm needs to be controlled to rotate the tube segment to be assembled around the x-axis of {seg1}. Adjust the distances h1 and h2 from points A and C along the negative z-axis of {seg1} to the arc-shaped inner surface of the assembled tube segment so that the height difference between h1 and h2 is within the allowable error range, so that when the tube segment to be assembled is translated along the negative z-axis of {seg1}, the axial arc-shaped side of the tube segment to be assembled and the assembled tube segment can fit together.

[0016] D. Negative translation along the z-axis of {seg1}: After adjusting the difference between h1 and h2 to the allowable error range, the robotic arm needs to be controlled to translate the tube segment along the negative z-axis of {seg1}. The real-time h1 during the translation process is measured using a line laser. When h1 is within the allowable error range, the robotic arm stops moving; otherwise, the robotic arm continues to move until h1 is within the allowable error range. After the negative translation along the z-axis of {seg1} is completed, the tube segment to be assembled and the axial arc side of the assembled tube segment are in contact with each other.

[0017] E. Rotation around the axial direction of the segment to be assembled: After the segment stops translating along the negative z-axis of {seg1}, the robotic arm needs to be controlled to rotate the segment to be assembled around the axial direction of the segment to be assembled, continuously reducing the gap error between the segment to be assembled and the straight edge of the assembled segment. The gap size is measured in real time using a line laser. When the gap is within the allowable range, the rotation stops; otherwise, the rotation continues until the gap is within the allowable error range.

[0018] F. End of assembly: After completing the above steps, the assembly gap and height difference are calculated by line laser measurement. If the assembly error requirements are met, the segment assembly is ended. Otherwise, the above process is repeated until the assembly error meets the requirements.

[0019] As a further aspect of the present invention: the poses of the segments to be assembled and the assembled segments in the coordinate system {b} of the assembly robot are measured using line lasers s1, s2 and s3, i.e., the transformation matrices between {seg1} and {seg2} and the coordinate system {b}. and

[0020] As a further aspect of the present invention: keeping the position of {seg1} unchanged in {b}, and taking the pose of {seg2} in the {b} coordinate system as the pose of {seg1}, the desired pose of {seg1} when the poses of {seg1} and {seg2} are consistent can be obtained. In this pose, the x, y, and z axes of {seg1} and {seg2} are parallel, meaning that the axial arc-shaped side of the segment to be assembled is parallel to that of the segment already assembled.

[0021] As a further aspect of the present invention: utilizing the desired pose of the tunnel segments during leveling. Find the robot arm to adjust the tunnel segment to The pose of the end effector of the robotic arm The robot arm's pose can then be determined using inverse kinematics. The required motion offset for each degree of freedom is used to level the axial arc-shaped side of the segment to be assembled with that of the already assembled segment.

[0022] As a further embodiment of the present invention: the coordinate systems of the three line laser sensors are {s1}, {s2}, {s3}, and the coordinates of A, B, C, A', B', and C' in the line laser sensor coordinate system can be obtained by the line laser, denoted as A. s1 =[x As1 y As1 , z As1 ] T B s2 =[x Bs2 y Bs2 , z Bs2 ] T C s3 =[x Cs3 y Cs3 , z Cs3 ] T A' s1 =[x A’s1 y A’s1 , z A’s1 ] T B' s2 =[x B’s2 y B’s2 , z B’s2 ] T C' s3 =[x C’s3 y C’s3 , z C’s3 ] T Let the coordinate system of the robotic arm's end effector be {t}, and the coordinate transformation matrices between each line laser and the robotic arm's end effector be as follows: The coordinates of each point in the coordinate system of the robotic arm's end effector are as follows: A t =[x At y At , z At ] T B t =[x Bt y Bt , z Bt] T C t =[x Ct y Ct , z Ct ] T A' t =[x A’t y A’t , z A’t ]T, B' t =[x B’t y B’t , z B’t ] T C' t =[x C’t y C’t , z C’t ] T Then we have:

[0023] #

[0024] #

[0025]

[0026]

[0027]

[0028] #

[0029] In the coordinate system {t} at the end of the robotic arm, we have:

[0030]

[0031]

[0032] Then in {seg1}:

[0033] A seg1 =[0,0,0] τ ;

[0034] B seg1 =[x Bseg1 ,y Bseg1 ,z Bseg1 ] τ ;

[0035] in:

[0036]

[0037]

[0038] In {seg2}:

[0039] A′ seg2 =[0, 0, 0] T ;

[0040]

[0041]

[0042]

[0043] As a further aspect of the present invention: let the transformation matrices between {seg1}, {seg2} and the actuator end coordinate system {t} be respectively... The transformation matrix between {t} and the robot arm's base coordinate system {b} is: Then we have:

[0044]

[0045]

[0046] It can be written in block form as rotation and translation matrices:

[0047]

[0048]

[0049] Then we have:

[0050]

[0051]

[0052] A t B t C t and A seg1 B seg1 C seg1 Separate centering treatment:

[0053]

[0054] Centroidalization can reduce translation vectors The influence of this can be considered, and thus the rotation matrix can be calculated first. Therefore, the coordinates of points A, B, and C in the coordinate systems {t} and {seg1} are obtained by centroidalization:

[0055]

[0056]

[0057] Rotation matrix It can be decomposed into:

[0058]

[0059] Where: I is the identity matrix; S is the antisymmetric matrix; a, b, and c are Rodrigues parameters;

[0060]

[0061] Equation (1) can then be rewritten as:

[0062]

[0063] Summarized as follows:

[0064] Δx = L;

[0065] in: Using the least squares principle, the Rodrigues parameters are obtained:

[0066] X = (A T A) -1 A T L;

[0067] Substituting the calculated a, b, and c into (4) yields S, which is then substituted back into (3) to obtain... Substituting into (1) again, we get Thus obtain Similarly, we can find and Therefore, it can be concluded that

[0068] but It can be obtained from the following formula:

[0069]

[0070] in, The initial measurement position of the robotic arm's end effector pose can be determined by combining the motion biases of each degree of freedom of the robotic arm with the positive kinematics. Therefore, we can conclude that:

[0071] As a further aspect of the present invention: to adjust the posture of the segment to be assembled, so that surface ABC is parallel to surface A'B'C', and the position of {seg1} remains unchanged, the desired pose of the equivalent rigid body ΔABC can be set as follows:

[0072]

[0073] As a further aspect of the present invention: since the relative position of the end effector and the segment remains unchanged after the robotic arm grasps the segment to be assembled, the segment assembly process... If it remains unchanged, the desired pose will be reached. Sometimes:

[0074]

[0075] From this, we can determine the position of the tunnel segment. At that time, the position of the end effector of the robotic arm

[0076]

[0077] The robot's pose at the target position can then be determined using inverse kinematics. The required motion offset for each degree of freedom is determined to control the assembly robot to adjust the axial arc-shaped side of the segment to be assembled to be parallel to that of the already assembled segment.

[0078] As a further aspect of the present invention: after the segment to be assembled is parallel to the axial arc side of the already assembled segment, the orientation of the segment to be assembled is kept unchanged, and the segment is moved along the positive x-axis of {seg1} to reduce the assembly gap error of the arc side. The method includes the following steps:

[0079] Step 1: Calculate the clearance in the x-axis direction:

[0080] x-axis direction vector:

[0081]

[0082] Since plane ABC is parallel to plane A'B'C' (already adjusted in step one), let the x-axis intersect plane A'B'C' at point P.

[0083] Then we have: AP⊥plane A'B'C', and A'P∈plane A'B'C', therefore: AP⊥A'P;

[0084] The distance d between plane ABC and plane A'B'C' is:

[0085]

[0086] Step 2: Calculate the translation pose along the x-axis:

[0087] Let each translation be Δx, where i is the i-th translation, and x = Δx·i is the translation amount relative to the initial position after the i-th translation. Let be the coordinate transformation matrix between the i-th translation of the segment to be assembled and its initial position. Then:

[0088]

[0089]

[0090] but:

[0091]

[0092] right By performing inverse kinematics, the motion bias required for each degree of freedom of the robot arm during the i-th translation can be calculated, thereby controlling the robot to continuously move the tube segment along the positive x-direction of {seg1}. When the gap between the arc-shaped side of the tube segment, i.e. the distance d between surface ABC and surface A'B'C', is less than the allowable error range, the translation stops.

[0093] As a further aspect of the present invention: adjusting the height difference by rotating the tube segment around the x-axis of {seg1}, the method includes the following steps:

[0094] Step 1: After the segment has been translated along the positive x-axis of {seg1}, the segment needs to be rotated around the x-axis of {seg1} to adjust the height difference. After the segment has been translated along the positive x-axis of {seg1}, look from the positive x-axis of {seg1} to the negative x-axis to get a side view of the inner arc edge of the segment to be assembled and the segment already assembled.

[0095] Step 2: Let the negative z-axis of {seg1} intersect the arc edge of the assembled segment at F. Draw a line parallel to the z-axis through point C, which intersects the arc edge of the assembled segment at G. When AF = CG, the segment to be assembled can be made to fit the arc edge of the assembled segment after moving |AF| distance along the negative z-axis.

[0096] Transform the coordinates of A', B', and C' to the {seg1} coordinate system:

[0097]

[0098] In the {seg1} coordinate system, it can be obtained from A′ seg1 B′ seg1 C′ seg1 The equation of the circle containing the arc edge of the assembled segment is obtained using coordinates. Let the equation of the circle be:

[0099]

[0100] Let F seg1 = (Δd, 0, -h1), Where Δd is the distance between face ABC and face A'B'C' after the second translation is completed. Substituting it into the equation of the circle, we can solve for h1 and h2 respectively.

[0101] A. tf h1-h2>0 and |h1-h2|>Δh;

[0102] Looking from the positive x-axis of {seg1} towards the negative x-axis, {seg1} rotates counterclockwise around the x-axis by Δθ each time. Therefore, the angle of rotation relative to the initial position after the i-th rotation is θ = Δθ·i. At this point, the coordinate system of the segment to be assembled becomes {seg1′}, and the rotation matrix is:

[0103]

[0104]

[0105] Let the position of the robotic arm's end effector after the i-th rotation be... Let's consider the pose of the robotic arm's end effector when the segment finishes translating along the positive x-axis of {seg1}. From the second step, we can see that... The rotation angles of each joint can be obtained through forward kinematics, then:

[0106]

[0107] Then the end-effector pose of the i-th rotating robotic arm can be obtained.

[0108]

[0109] Depend on By combining inverse kinematics, the angles of rotation required for each joint relative to its initial position in the i-th rotation can be obtained.

[0110] B. If h1-h2<0 and |h1-h2|>Δh;

[0111] Rotate clockwise, at this time:

[0112]

[0113] Similarly, the answer can be found;

[0114] C. |h1-h2|>Δh;

[0115] If the height difference is within the allowable error range, stop the rotation, record the rotation angle of each joint at this time, and use forward kinematics to obtain the actual pose of the actuator end effector at this time.

[0116] As a further aspect of the present invention: the segment is translated along the negative z-axis of {seg1}. After the segment height difference adjustment is completed, the segment is translated along the negative z-axis of {seg1} so that the arc edge of the segment to be assembled fits with the arc edge of the assembled segment (the arc edges of the two segments are within the inner arc surface of the assembled segment), so that h1 is within the allowable error range. Assuming that each downward translation Δz > 0, then after i translations, the translation amount relative to the initial position is z = Δz·i. Let... Let be the coordinate transformation matrix between the i-th translation of the segment to be assembled and its initial position. Then:

[0117]

[0118]

[0119] but:

[0120]

[0121] right By performing inverse kinematics, the motion deviation required for the i-th translation of the robot arm's degree of freedom relative to the initial translation position along the negative z-axis can be calculated. The segment moves continuously along the negative z-axis of {seg1}, and the translation stops when h1 is within the allowable error range.

[0122] As a further aspect of the present invention: reducing the gap between the straight edges of the segments to be assembled and the already assembled segments, the method includes the following steps:

[0123] A. After the segment is translated along the negative z-axis of {seg1}, the arc-shaped side of the segment to be assembled is fitted with the segment already assembled. At this time, the segment needs to be rotated around the axis of the inner surface of the segment so that the gap between the straight edge of the segment to be assembled and the segment already assembled is continuously reduced. When the gap between the two straight edges is within the allowable error range, the rotation is stopped and the segment assembly is completed.

[0124] B. Rotational pose calculation:

[0125] In the {seg1} coordinate system, by A seg1 B eg1 C seg1 The coordinates of the center of the circle containing the arc edge of the segment to be assembled can be determined. Let the center of the circle be O(a′, b′, c′). Establish a coordinate system {seg0} with O as the origin, whose x, y, and z axes are aligned with the direction of {seg1}. Then the transformation matrix from {seg0} to {seg1} is... for:

[0126]

[0127] in I is the identity matrix.

[0128] Looking from the positive x-axis of {seg0} to the negative x-axis, the gap between the assembled pipe segment and the straight edge of the assembled pipe segment can only be reduced by rotating the assembled pipe segment counterclockwise around the x-axis of {seg0} (the specific direction of rotation is determined by the position of the straight edge of the assembled pipe segment).

[0129] Let Δβ be the rotation each time, then the angle β of the rotation relative to the initial {seg0} position after the i-th rotation is Δβ·i;

[0130]

[0131]

[0132] Let the position of the robotic arm's end effector after the i-th rotation be... Let be the pose of the robotic arm's end effector when the segment is translated along the negative z-axis of {seg1}. From step four, we can see that... Since the rotation angles of each joint can be obtained through normal kinematics, then:

[0133]

[0134] Then the end-effector pose of the i-th rotating robotic arm can be obtained.

[0135]

[0136] Depend on By combining inverse kinematics, the angles of rotation required for each joint relative to its initial position in the i-th rotation can be obtained.

[0137] C. Calculation of straight edge clearance:

[0138] The laser line of the fourth line laser s4 intersects the straight edges of the segments to be assembled and the assembled segments at E and E'. The laser line of the fifth line laser s5 intersects the straight edges of the segments to be assembled and the assembled segments at D and D'. From the second step, we know that in the {t} coordinate system, the x-axis direction vector of {seg1}... It has been determined that the straight edge of the segment to be assembled is perpendicular to plane ABC:

[0139]

[0140] in, This is the transformation matrix between the line laser S4 and the coordinate system of the robotic arm's end effector. Let be the transformation matrix between the line laser s5 and the coordinate system of the robotic arm's end effector. Both can be obtained from the hand-eye calibration between the line laser and the robotic arm's end effector. Let gap be the distance between the two straight edges, then:

[0141]

[0142] When gap < δ, that is, when the gap between the two straight edges is within the allowable error range, the segment assembly is completed.

[0143] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions:

[0144] (1) The shield tunnel segment automated assembly system based on line laser sensors in this scheme includes a six-degree-of-freedom assembly robot and line laser sensors. The system uses five line laser sensors, all of which are fixedly installed on the robot's gripping plate. When the assembly robot grips the segment to be assembled and sends it to the rough assembly position, the five line laser sensors can simultaneously illuminate the edges of the segment to be assembled and the assembled segment. Three of the line laser sensors illuminate the arc-shaped sides of the segment to be assembled and the assembled segment, while the other two line laser sensors illuminate the straight edges of the segment to be assembled and the assembled segment. The depth change points of the three-dimensional object edge illuminated by the line laser are used as feature points. The segment pose and assembly error are calculated by measuring and calculating the coordinates of these feature points in different coordinate systems. The assembly robot control commands are derived from the robot's inverse kinematics to control the robot to achieve high-precision automated assembly of the shield tunnel segments.

[0145] (2) The line laser sensor used in this solution has the characteristics of high measurement accuracy and is not affected by construction lighting. It can be applied to the high-precision automated assembly of shield tunnel segments under various working conditions. The coordinates of the depth change point of the line laser irradiating the edge of the segment are used to calculate the segment pose and assembly error. This reduces the operation process of using marking to achieve automated assembly of segments, reduces time costs, and at the same time reduces the impact of the marking position error on the segment assembly accuracy.

[0146] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0147] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0148] Figure 1 This is a schematic diagram of the installation and deployment of the line laser of the present invention;

[0149] Figure 2 This is a schematic diagram of the segment coordinate system of the present invention;

[0150] Figure 3 This is a flowchart of the algorithm of the present invention;

[0151] Figure 4 This is a schematic diagram of the segment leveling of the present invention;

[0152] Figure 5 This is a schematic diagram before the translation of the present invention is completed;

[0153] Figure 6 This is a schematic diagram after the translation of the present invention is completed;

[0154] Figure 7 This is a side view of the inner arc edge adjacent to the segment to be assembled and the already assembled segment of the present invention;

[0155] Figure 8 This is a schematic diagram of the final segment pose after the present invention moves along the negative z-axis of {seg1}.

[0156] Figure 9 This is a schematic diagram of the tube segment of the present invention rotating around the axis of its inner surface. Detailed Implementation

[0157] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0158] It is important to note that terms such as "first," "second," "symmetric," and "array" are used only to distinguish between descriptive and positional descriptions and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features specified with terms such as "first" or "symmetric" may explicitly or implicitly include one or more of that feature; similarly, when the quantity of certain features is not limited by words such as "two" or "three," it should be noted that such features also explicitly or implicitly include one or more features.

[0159] In this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," and "fixation" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral molding; they can refer to a mechanical connection, a direct connection, a welding connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the accompanying drawings and specific circumstances.

[0160] The automated assembly method for tunnel boring machine segments based on line laser sensors includes the following steps:

[0161] like Figure 1As shown, in step one, the installation and deployment of line lasers involves using five line laser sensors to measure the pose of the tube segments and the assembly error of the tube segments. All line laser sensors are fixedly mounted on the robot's gripping plate. When the robot grips the tube segment and delivers it to the rough assembly position, each line laser can just illuminate the edges of the assembled tube segment and the tube segment to be assembled. Three line lasers illuminate the curved side of the tube segment, with random intersection points with the edge of the tube segment to be assembled designated as A, B, and C; and random intersection points with the curved side edge of the assembled tube segment designated as A', B', and C'. Two line lasers illuminate the straight edge of the tube segment, with random intersection points with the straight edge edge of the tube segment to be assembled designated as D and E; and random intersection points with the straight edge edge of the assembled tube segment designated as D' and E'.

[0162] like Figure 2 As shown, in step two, coordinate system establishment, a coordinate system {seg1} for the segments to be assembled and a coordinate system {seg2} for the assembled segments are established with A and A' as origins. In the {seg1} coordinate system, the x-axis is perpendicular to surface ABC, and the y-axis is along line AB. In the {seg2} coordinate system, the x-axis is perpendicular to surface A'B'C', and the y-axis is along line A'B'. Line laser 1 illuminates A and A', line laser 2 illuminates B and B', and line laser 3 illuminates C and C'. The coordinate systems of the three line lasers are {s1}, {s2}, and {s3}, respectively. Let the coordinate system of the robotic arm end effector be {t}, and the robot base coordinate system be {b}.

[0163] like Figure 3 As shown, step three, the automated assembly posture measurement algorithm for tunnel segments, includes the following control flow:

[0164] A. Leveling: Leveling refers to adjusting the pose of the tube segment to be assembled so that the axial arc side of the tube segment to be assembled is parallel to that of the already assembled tube segment, i.e., surface ABC is parallel to surface A'B'C'. Line lasers s1, s2 and s3 are used to measure the pose of the tube segment to be assembled and the already assembled tube segment in the robot's base coordinate system. Keeping the position of the tube segment to be assembled unchanged, the pose of the already assembled tube segment is used as the desired pose. The desired pose when the axial arc side of the tube segment to be assembled is adjusted to be parallel to that of the already assembled tube segment is solved. Then, the desired pose of the end effector of the robot is solved after leveling. Combining the robot's inverse kinematics, the motion bias required to reach each degree of freedom of the desired pose is solved. Based on the bias, the robot is controlled to adjust the tube segment to be assembled so that its axial side is parallel to that of the already assembled tube segment.

[0165] B. Translation along the positive x-axis of {seg1}: After leveling, the robot needs to translate the tube segment to be assembled along the positive x-axis of the coordinate system {seg1} of the tube segment to be assembled to reduce the gap between the tube segment to be assembled and the axial arc side of the assembled tube segment. The gap between the tube segment to be assembled and the axial arc side of the assembled tube segment is calculated by measuring with line lasers s1, s2, and s3. It is then determined whether the gap is within the allowable error range. If it is within the allowable error range, the translation movement is stopped; otherwise, the translation movement continues until the error is within the allowable range.

[0166] C. Adjust the rotation of the tube segment around the x-axis of {seg1}: After the tube segment is translated along the positive x-axis of {seg1} so that the gap between the tube segment to be assembled and the axial arc-shaped side of the assembled tube segment is within the allowable error range and the translation stops, the robotic arm needs to be controlled to rotate the tube segment to be assembled around the x-axis of {seg1}. Adjust the distances h1 and h2 from points A and C along the negative z-axis of {seg1} to the arc-shaped inner surface of the assembled tube segment so that the height difference between h1 and h2 is within the allowable error range, so that when the tube segment to be assembled is translated along the negative z-axis of {seg1}, the axial arc-shaped side of the tube segment to be assembled and the assembled tube segment can fit together.

[0167] D. Negative translation along the z-axis of {seg1}: After adjusting the difference between h1 and h2 to the allowable error range, the robotic arm needs to be controlled to translate the tube segment along the negative z-axis of {seg1}. The real-time h1 during the translation process is measured using a line laser. When h1 is within the allowable error range, the robotic arm stops moving; otherwise, the robotic arm continues to move until h1 is within the allowable error range. After the negative translation along the z-axis of {seg1} is completed, the tube segment to be assembled and the axial arc side of the assembled tube segment are in contact with each other.

[0168] E. Rotation around the axial direction of the segment to be assembled: After the segment stops translating along the negative z-axis of {seg1}, the robotic arm needs to be controlled to rotate the segment to be assembled around the axial direction of the segment to be assembled, continuously reducing the gap error between the segment to be assembled and the straight edge of the assembled segment. The gap size is measured in real time using a line laser. When the gap is within the allowable range, the rotation stops; otherwise, the rotation continues until the gap is within the allowable error range.

[0169] F. End of assembly: After completing the above steps, the assembly gap and height difference are calculated by line laser measurement. If the assembly error requirements are met, the segment assembly is ended. Otherwise, the above process is repeated until the assembly error meets the requirements.

[0170] like Figure 4 As shown, in one specific embodiment,

[0171] Step 1: Adjust the axial arc-shaped side of the segment to be assembled to be parallel to that of the already assembled segment.

[0172] The poses of the segments to be assembled and the assembled segments in the coordinate system {b} of the assembly robot are measured using line lasers s1, s2, and s3, i.e., the transformation matrices between {seg1} and {seg2} and the coordinate system {b}. and

[0173] In one embodiment, keeping the position of {seg1} unchanged in {b}, and using the pose of {seg2} in the {b} coordinate system as the pose of {seg1}, the desired pose of {seg1} when the poses of {seg1} and {seg2} are consistent can be obtained. In this pose, the x, y, and z axes of {seg1} and {seg2} are parallel, meaning that the axial arc-shaped side of the segment to be assembled is parallel to that of the segment already assembled.

[0174] In one embodiment, the desired pose of the tunnel segment is achieved by leveling. Find the robot arm to adjust the tunnel segment to The pose of the end effector of the robotic arm The robot arm's pose can then be determined using inverse kinematics. The required motion offset for each degree of freedom is used to level the axial arc-shaped side of the segment to be assembled with that of the already assembled segment.

[0175] In one embodiment, the coordinate systems of the three line laser sensors are {s1}, {s2}, and {s3}, respectively. The coordinates of A, B, C, A', B', and C' in the line laser sensor coordinate system can be obtained from the line laser, denoted as A. s1 =[x As1 y As1 , z As1 ] T B s2 =[x Bs2 y Bs2 , z Bs2 ] T C s3 =[x Cs3 y Cs3 , z Cs3 ] T A' s1 =[x A’s1 y A’s1 , z A’s1 ] T B' s2 =[x B’s2 y B’s2 , z B’s2 ] T C' s3 =[x C’s3 y C’s3 , z C’s3 ]T Let the coordinate system of the robotic arm's end effector be {t}, and the coordinate transformation matrices between each line laser and the robotic arm's end effector be as follows: The coordinates of each point in the coordinate system of the robotic arm's end effector are as follows: A t =[x At y At , z At ] T B t =[x Bt y Bt , z Bt ] T C t =[x Ct y Ct , z Ct ] T A' t =[x A’t y A’t , z A’t ]T, B' t =[x B’t y B’t , z B’t ] T C' t =[x C’t y C’t , z C’t ] T Then we have:

[0176] #

[0177] #

[0178]

[0179]

[0180]

[0181] #

[0182] In the coordinate system {t} at the end of the robotic arm, we have:

[0183]

[0184]

[0185] Then in {seg1}:

[0186]

[0187] B seg1=[x Biseg1 y Biseg1 , z Biseg1 ] T ;

[0188] in:

[0189]

[0190]

[0191] In {seg2}:

[0192] A′ seg2 =[0, 0, 0] T ;

[0193] B′ seg2 =[x Biseg2 y Biseg2 , z Biseg2 ] T ;

[0194]

[0195]

[0196] In one embodiment, let the transformation matrices between {seg1}, {seg2} and the actuator end coordinate system {t} be respectively... The transformation matrix between {t} and the robot arm's base coordinate system {b} is: Then we have:

[0197]

[0198]

[0199] It can be written in block form as rotation and translation matrices:

[0200]

[0201]

[0202] Then we have:

[0203]

[0204]

[0205] A t B t C t and A seg1 B seg1 C seg1Separate centering treatment:

[0206]

[0207] Centroidalization can reduce translation vectors The influence of this can be considered, and thus the rotation matrix can be calculated first. Therefore, the coordinates of points A, B, and C in the coordinate systems {t} and {seg1} are obtained by centroidalization:

[0208]

[0209]

[0210] Rotation matrix It can be decomposed into:

[0211]

[0212] Where: I is the identity matrix; S is the antisymmetric matrix; a, b, and c are Rodrigues parameters;

[0213]

[0214] Equation (1) can then be rewritten as:

[0215] #

[0216] Summarized as follows:

[0217] AX = L;

[0218] in: Using the least squares principle, the Rodrigues parameters are obtained:

[0219] x=(A T A) -1 A T L;

[0220] Substituting the calculated a, b, and c into (4) yields S, which is then substituted back into (3) to obtain... Substituting into (1) again, we get Thus obtain Similarly, we can find and Therefore, it can be concluded that

[0221] but It can be obtained from the following formula:

[0222]

[0223] in, The initial measurement position of the robotic arm's end effector pose can be determined by combining the motion biases of each degree of freedom of the robotic arm with the positive kinematics. Therefore, we can conclude that:

[0224] In one embodiment, to adjust the orientation of the segment to be assembled so that surface ABC is parallel to surface A'B'C' while keeping the position of {seg1} unchanged, the desired orientation of the equivalent rigid body ΔABC can be set as follows:

[0225]

[0226] In one embodiment, since the end effector and the segment remain in the same relative position after the robotic arm grasps the segment to be assembled, the segment assembly process... If it remains unchanged, the desired pose will be reached. Sometimes:

[0227]

[0228] From this, we can determine the position of the tunnel segment. At that time, the position of the end effector of the robotic arm

[0229]

[0230] The robot's pose at the target position can then be determined using inverse kinematics. The required motion offset for each degree of freedom is determined to control the assembly robot to adjust the axial arc-shaped side of the segment to be assembled to be parallel to that of the already assembled segment.

[0231] like Figure 5-6 As shown, in one specific embodiment, after the entire segment to be assembled is parallel to the axial arc side of the already assembled segment, the orientation of the segment to be assembled is kept unchanged, and the segment is moved along the positive x-axis of {seg1} to reduce the assembly gap error of the arc side. The method includes the following steps:

[0232] Step 1: Calculate the clearance in the x-axis direction:

[0233] x-axis direction vector:

[0234]

[0235] Since plane ABC is parallel to plane A'B'C' (already adjusted in step one), let the x-axis intersect plane A'B'C' at point P.

[0236] Then we have: AP⊥plane A'B'C', and A'P∈plane A'B'C', therefore: AP⊥A'P;

[0237] The distance d between plane ABC and plane A'B'C' is:

[0238]

[0239] Step 2: Calculate the translation pose along the x-axis:

[0240] Let each translation be Δx, where i is the i-th translation, and x = Δx·1 is the translation amount relative to the initial position after the i-th translation. Let be the coordinate transformation matrix between the i-th translation of the segment to be assembled and its initial position. Then:

[0241]

[0242]

[0243] but:

[0244]

[0245] right By performing inverse kinematics, the motion bias required for each degree of freedom of the robot arm during the i-th translation can be calculated, thereby controlling the robot to continuously move the tube segment along the positive x-direction of {seg1}. When the gap between the arc-shaped side of the tube segment, i.e. the distance d between surface ABC and surface A'B'C', is less than the allowable error range, the translation stops.

[0246] like Figure 7 As shown, in one specific embodiment, the height difference is adjusted by rotating the tube segment around the x-axis of {seg1}, and the method includes the following steps:

[0247] Step 1: After the segment has been translated along the positive x-axis of {seg1}, the segment needs to be rotated around the x-axis of {seg1} to adjust the height difference. After the segment has been translated along the positive x-axis of {seg1}, look from the positive x-axis of {seg1} to the negative x-axis to get a side view of the inner arc edge of the segment to be assembled and the segment already assembled.

[0248] Step 2: Let the negative z-axis of {seg1} intersect the arc edge of the assembled segment at F. Draw a line parallel to the z-axis through point C, which intersects the arc edge of the assembled segment at G. When AF = CG, the segment to be assembled can be made to fit the arc edge of the assembled segment after moving |AF| distance along the negative z-axis.

[0249] Transform the coordinates of A', B', and C' to the {seg1} coordinate system:

[0250]

[0251] In the {seg1} coordinate system, it can be obtained from A′ seg1 B′ seg1 , c′ seg1 The equation of the circle containing the arc edge of the assembled segment is obtained using coordinates. Let the equation of the circle be:

[0252]

[0253] Let F seg1 = (Δd, 0, -h1), Where Δd is the distance between face ABC and face A'B'C' after the second translation is completed. Substituting it into the equation of the circle, we can solve for h1 and h2 respectively.

[0254] A. If h1-h2>0 and |h1-h2|>Δh;

[0255] Looking from the positive x-axis of {seg1} towards the negative x-axis, {seg1} rotates counterclockwise around the x-axis by Δθ each time. Therefore, the angle of rotation relative to the initial position after the i-th rotation is θ = Δθ·i. At this point, the coordinate system of the segment to be assembled becomes {seg1′}, and the rotation matrix is:

[0256]

[0257]

[0258] Let the position of the robotic arm's end effector after the i-th rotation be... Let's consider the pose of the robotic arm's end effector when the segment finishes translating along the positive x-axis of {seg1}. From the second step, we can see that... The rotation angles of each joint can be obtained through forward kinematics, then:

[0259]

[0260] Then the end-effector pose of the i-th rotating robotic arm can be obtained.

[0261]

[0262] Depend on By combining inverse kinematics, the angles of rotation required for each joint relative to its initial position in the i-th rotation can be obtained.

[0263] B. If h1-h2 < 0 and |h1-h2| > Δh;

[0264] Rotate clockwise, at this time:

[0265]

[0266] Similarly, the answer can be found;

[0267] C. |h1-h2|>Δh;

[0268] If the height difference is within the allowable error range, stop the rotation, record the rotation angle of each joint at this time, and use forward kinematics to obtain the actual pose of the actuator end effector at this time.

[0269] like Figure 8 As shown, in a specific embodiment, the segment is translated along the negative z-axis of {seg1}. After the segment height difference adjustment is completed, the segment is translated along the negative z-axis of {seg1} so that the arc edge of the segment to be assembled fits with the arc edge of the assembled segment (the arc edges of the two segments are within the inner arc surface of the assembled segment), so that h1 is within the allowable error range. Assuming that each downward translation Δz > 0, then after i translations, the translation amount relative to the initial position is z = Δz·i. Let... Let be the coordinate transformation matrix between the i-th translation of the segment to be assembled and its initial position. Then:

[0270]

[0271]

[0272] but:

[0273]

[0274] right By performing inverse kinematics, the motion deviation required for the i-th translation of the robot arm's degree of freedom relative to the initial translation position along the negative z-axis can be calculated. The segment moves continuously along the negative z-axis of {seg1}, and the translation stops when h1 is within the allowable error range.

[0275] like Figure 9 As shown, in one specific embodiment, the method for reducing the straight edge gap between the segment to be assembled and the already assembled segment includes the following steps:

[0276] A. After the segment is translated along the negative z-axis of {seg1}, the arc-shaped side of the segment to be assembled is fitted with the segment already assembled. At this time, the segment needs to be rotated around the axis of the inner surface of the segment so that the gap between the straight edge of the segment to be assembled and the segment already assembled is continuously reduced. When the gap between the two straight edges is within the allowable error range, the rotation is stopped and the segment assembly is completed.

[0277] B. Rotational pose calculation:

[0278] In the {seg1} coordinate system, by A seg1 B seg1 C seg1 The coordinates of the center of the circle containing the arc edge of the segment to be assembled can be determined. Let the center of the circle be O(a′, b′, c′). Establish a coordinate system {seg0} with O as the origin, whose x, y, and z axes are aligned with the direction of {seg1}. Then the transformation matrix from {seg0} to {seg1} is... for:

[0279]

[0280] in I is the identity matrix.

[0281] Looking from the positive x-axis of {seg0} to the negative x-axis, the gap between the assembled pipe segment and the straight edge of the assembled pipe segment can only be reduced by rotating the assembled pipe segment counterclockwise around the x-axis of {seg0} (the specific direction of rotation is determined by the position of the straight edge of the assembled pipe segment).

[0282] Let Δβ be the rotation each time, then the angle β of the rotation relative to the initial {seg0} position after the i-th rotation is Δβ·i;

[0283]

[0284]

[0285] Let the position of the robotic arm's end effector after the i-th rotation be... Let be the pose of the robotic arm's end effector when the segment is translated along the negative z-axis of {seg1}. From step four, we can see that... Since the rotation angles of each joint can be obtained through normal kinematics, then:

[0286]

[0287] Then the end-effector pose of the i-th rotating robotic arm can be obtained.

[0288]

[0289] Depend on By combining inverse kinematics, the angles of rotation required for each joint relative to its initial position in the i-th rotation can be obtained.

[0290] C. Calculation of straight edge clearance:

[0291] The laser line of the fourth line laser s4 intersects the straight edges of the segments to be assembled and the assembled segments at E and E'. The laser line of the fifth line laser s5 intersects the straight edges of the segments to be assembled and the assembled segments at D and D'. From the second step, we know that in the {t} coordinate system, the x-axis direction vector of {seg1}... It has been determined that the straight edge of the segment to be assembled is perpendicular to plane ABC:

[0292]

[0293] in, This is the transformation matrix between the line laser S4 and the coordinate system of the robotic arm's end effector. Let be the transformation matrix between the line laser s5 and the coordinate system of the robotic arm's end effector. Both can be obtained from the hand-eye calibration between the line laser and the robotic arm's end effector. Let gap be the distance between the two straight edges, then:

[0294]

[0295] When gap < δ, that is, when the gap between the two straight edges is within the allowable error range, the segment assembly is completed.

[0296] The above is the overall workflow of this invention. Simply repeat this process the next time you use it.

[0297] In the several embodiments provided in this application, it should be understood that the disclosed terminals, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0298] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units. The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An automated assembly method for tunnel boring machine segments based on a line laser sensor, characterized in that, Includes the following steps: Step 1: Installation and deployment of the line laser; Step 2: Establishing the coordinate system; Step 3: Algorithm for Automated Assembly Position Measurement of Tunnel Segments; Step one uses five line laser sensors to measure the pose of the tube segments and the assembly error of the tube segments. The line laser sensors are all fixedly mounted on the robot's gripping plate. When the robot grips the tube segment and delivers it to the rough assembly position, each line laser can just illuminate the edges of the assembled tube segment and the tube segment to be assembled. Three line lasers illuminate the arc-shaped side of the tube segment, and the random intersection points with the edge of the tube segment to be assembled are set as A, B, and C, respectively; the random intersection points with the arc-shaped side edge of the assembled tube segment are set as A', B', and C', respectively; two line lasers illuminate the straight edge of the tube segment, and the random intersection points with the straight edge edge of the tube segment to be assembled are set as D and E, respectively; the random intersection points with the straight edge edge of the assembled tube segment are set as D' and E', respectively. In step two, coordinate systems {seg1} and {seg2} are established with A and A' as origins. In coordinate system {seg1}, the x-axis is perpendicular to surface ABC and the y-axis is along line AB. In coordinate system {seg2}, the x-axis is perpendicular to surface A'B'C' and the y-axis is along line A'B'. Line laser 1 illuminates A and A', line laser 2 illuminates B and B', and line laser 3 illuminates C and C'. The coordinate systems of the three line lasers are {s1}, {s2}, and {s3}, respectively. Let the coordinate system of the robotic arm end effector be {t} and the robot base coordinate system be {b}. The algorithm control process in step three includes the following steps: A. Leveling: Leveling refers to adjusting the pose of the tube segment to be assembled so that the axial arc side of the tube segment to be assembled is parallel to that of the already assembled tube segment, i.e., surface ABC is parallel to surface A'B'C'. Line lasers s1, s2 and s3 are used to measure the pose of the tube segment to be assembled and the already assembled tube segment in the robot's base coordinate system. Keeping the position of the tube segment to be assembled unchanged, the pose of the already assembled tube segment is used as the desired pose. The desired pose when the axial arc side of the tube segment to be assembled is adjusted to be parallel to that of the already assembled tube segment is solved. Then, the desired pose of the end effector of the robot is solved after leveling. Combining the robot's inverse kinematics, the motion bias required to reach each degree of freedom of the desired pose is solved. Based on the bias, the robot is controlled to adjust the tube segment to be assembled so that its axial side is parallel to that of the already assembled tube segment. B. Translation along the positive x-axis of {seg1}: After leveling, the robot needs to translate the tube segment to be assembled along the positive x-axis of the coordinate system {seg1} of the tube segment to be assembled to reduce the gap between the tube segment to be assembled and the axial arc side of the assembled tube segment. The gap between the tube segment to be assembled and the axial arc side of the assembled tube segment is calculated by measuring with line lasers s1, s2, and s3. It is then determined whether the gap is within the allowable error range. If it is within the allowable error range, the translation movement is stopped; otherwise, the translation movement continues until the error is within the allowable range. C. Adjust the rotation of the tube segment around the x-axis of {seg1}: After the tube segment is translated along the positive x-axis of {seg1} so that the gap between the tube segment to be assembled and the axial arc-shaped side of the assembled tube segment is within the allowable error range and the translation stops, the robotic arm needs to be controlled to rotate the tube segment to be assembled around the x-axis of {seg1}. Adjust the distances h1 and h2 from points A and C along the negative z-axis of {seg1} to the arc-shaped inner surface of the assembled tube segment so that the height difference between h1 and h2 is within the allowable error range, so that when the tube segment to be assembled is translated along the negative z-axis of {seg1}, the axial arc-shaped side of the tube segment to be assembled and the assembled tube segment can fit together. D. Negative translation along the z-axis of {seg1}: After adjusting the difference between h1 and h2 to the allowable error range, the robotic arm needs to be controlled to translate the tube segment along the negative z-axis of {seg1}. The real-time h1 during the translation process is measured using a line laser. When h1 is within the allowable error range, the robotic arm stops moving; otherwise, the robotic arm continues to move until h1 is within the allowable error range. After the negative translation along the z-axis of {seg1} is completed, the tube segment to be assembled and the axial arc side of the assembled tube segment are in contact with each other. E. Rotation around the axial direction of the segment to be assembled: After the segment stops translating along the negative z-axis of {seg1}, the robotic arm needs to be controlled to rotate the segment to be assembled around the axial direction of the segment to be assembled, continuously reducing the gap error between the segment to be assembled and the straight edge of the assembled segment. The gap size is measured in real time using a line laser. When the gap is within the allowable range, the rotation stops; otherwise, the rotation continues until the gap is within the allowable error range. F. End of assembly: After completing the above steps, the assembly gap and height difference are calculated by line laser measurement. If the assembly error requirements are met, the segment assembly is ended. Otherwise, the above process is repeated until the assembly error meets the requirements.

2. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: The poses of the segments to be assembled and the assembled segments in the coordinate system {b} of the assembly robot are measured using line lasers s1, s2, and s3, i.e., the transformation matrices between {seg1} and {seg2} and the coordinate system {b}. and .

3. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: Keeping the position of {seg1} unchanged in {b}, and taking the pose of {seg2} in the {b} coordinate system as the pose of {seg1}, we can obtain the desired pose of {seg1} when the poses of {seg1} and {seg2} are the same. In this pose, the x, y, and z axes of {seg1} and {seg2} are parallel, meaning that the axial arc-shaped side of the segment to be assembled is parallel to that of the segment already assembled.

4. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: Desired pose of tunnel segments during leveling Find the robot arm to adjust the tunnel segment to The pose of the end effector of the robotic arm Then, the robot's pose can be determined using the robot's inverse kinematics. The required motion offset for each degree of freedom is used to level the axial arc-shaped side of the segment to be assembled with that of the already assembled segment.

5. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: The coordinate systems of the three line laser sensors are {s1}, {s2}, and {s3}. The coordinates of A, B, C, A', B', and C' in the line laser sensor coordinate system can be obtained from the line laser, and are denoted as A. s1 =[x As1 y As1 , z As1 ] T B s2 =[x Bs2 y Bs2 , z Bs2 ] T C s3 =[x Cs3 y Cs3 , z Cs3 ] T A' s1 =[x A’s1 y A’s1 , z A’s1 ] T B' s2 =[x B’s2 y B’s2 , z B’s2 ] T C' s3 =[x C’s3 y C’s3 , z C’s3 ] T Let the coordinate system of the robotic arm's end effector be {t}, and the coordinate transformation matrices between each line laser and the robotic arm's end effector be as follows: , , The coordinates of each point in the coordinate system of the robotic arm's end effector are as follows: A t =[x At y At , z At ] T B t =[x Bt y Bt , z Bt ] T C t =[x Ct y Ct , z Ct ] T A' t =[x A’t y A’t , z A’t ]T, B' t =[x B’t y B’t , z B’t ] T C' t =[x C’t y C’t , z C’t ] T Then we have: ； ； ； ； ； ； In the coordinate system {t} at the end of the robotic arm, we have: ； ； Then in {seg1}: ； ； in: ； ； In {seg2}: ； ； ； 。 6. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: Let the transformation matrices between {seg1}, {seg2} and the actuator end coordinate system {t} be respectively , The transformation matrix between {t} and the robot arm's base coordinate system {b} is: Then we have: ；（1） ；（2） , It can be written in block form as rotation and translation matrices: ； ； Then we have: ； ； Will , , and , , Separate centering treatment: ； Centroidalization can reduce translation vectors The influence of this can be considered, and thus the rotation matrix can be calculated first. Therefore, by centroidalizing the coordinates of points A, B, and C in the coordinate systems {t} and {seg1}, we obtain: ； ； Rotation matrix It can be decomposed into: ；（3） in: For unit array; The matrix is ​​antisymmetric; a, b, and c are Rodrigues parameters; ；（4） Then equation (1) can be rewritten as: ； Summarized as follows: ； in: Using the least squares principle, the Rodrigues parameters are obtained: ； Substitute the calculated a, b, and c into (4) to obtain S, then substitute them into (3) to get... Substituting this into (1) yields Thus obtain Similarly, we can find and Therefore, we can conclude that ; but , It can be obtained from the following formula: ； in, The initial measurement position of the robotic arm's end effector pose can be determined by combining the motion biases of each degree of freedom of the robotic arm with the forward kinematics; from this, we can conclude that: , , , .

7. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: To adjust the orientation of the segments to be assembled, making surface ABC parallel to surface A'B'C' while keeping the position of {seg1} unchanged, the equivalent rigid body can be made... The desired pose is: 。 8. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: Since the relative position of the end effector and the segment remains unchanged after the robotic arm grasps the segment to be assembled, the segment assembly process... If it remains unchanged, the desired pose will be reached. Sometimes: ； From this, we can determine the position of the tunnel segment. At that time, the position of the end effector of the robotic arm : ； The robot's pose at the target position can then be determined using inverse kinematics. The required motion offset for each degree of freedom is determined to control the assembly robot to adjust the axial arc-shaped side of the segment to be assembled to be parallel to that of the already assembled segment.

9. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that, After aligning the axial arc side of the segment to be assembled with that of the already assembled segment, maintain the orientation of the segment to be assembled and move it along the positive x-axis of {seg1} to reduce the assembly gap error of the arc side. The method includes the following steps: Step 1: Calculate the clearance in the x-axis direction: x-axis direction vector: ； Since plane ABC is parallel to plane A'B'C', let the x-axis intersect plane A'B'C' at point P. Then we have: AP⊥plane A'B'C'. And A'P∈plane A'B'C', so AP⊥A'P. The distance d between plane ABC and plane A'B'C' is: ； Step 2: Calculate the translation pose along the x-axis: Assume each translation , where i is the i-th translation. Let be the translation amount relative to the initial position after the i-th translation. Let be the coordinate transformation matrix between the i-th translation of the segment to be assembled and its initial position. Then: ； ； but: ； right By performing inverse kinematics, the motion bias required for each degree of freedom of the robot arm during the i-th translation can be calculated, thereby controlling the robot to continuously move the tube segment along the positive x-direction of {seg1}. When the gap between the arc-shaped side of the tube segment, i.e. the distance d between surface ABC and surface A'B'C', is less than the allowable error range, the translation stops.

10. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that, The method for adjusting the height difference by rotating the tube segment around the x-axis of {seg1} includes the following steps: Step 1: After the segment has been translated along the positive x-axis of {seg1}, the segment needs to be rotated around the x-axis of {seg1} to adjust the height difference. After the segment has been translated along the positive x-axis of {seg1}, look from the positive x-axis of {seg1} to the negative x-axis to get a side view of the inner arc edge of the segment to be assembled and the segment already assembled. Step 2: Let the negative z-axis of {seg1} intersect the arc edge of the assembled segment at F. Draw a line parallel to the z-axis through point C, intersecting the arc edge of the assembled segment at G. When At that time, the segments to be assembled move along the negative z-axis. The distance allows the arc edges of the segments to be assembled to fit snugly against those of the already assembled segments; Transform the coordinates of A', B', and C' to the {seg1} coordinate system: ； In the {seg1} coordinate system, it can be obtained from , , The equation of the circle containing the arc edge of the assembled segment is obtained using coordinates. Let the equation of the circle be: ； set up , ,in, Let be the distance between face ABC and face A'B'C' after the second translation step. Substituting these distances into the equation of the circle, we can solve for the answer. , ; A, and ; Looking from the positive x-axis of {seg1} towards the negative x-axis, {seg1} rotates counterclockwise around the x-axis. Each rotation... Then, the angle of rotation relative to the initial position after the i-th rotation is . At this point, the coordinate system of the segment to be assembled becomes Rotation matrix: ； ； Let the position of the robotic arm's end effector after the i-th rotation be... , Let's consider the pose of the robotic arm's end effector when the segment finishes translating along the positive x-axis of {seg1}. From the second step, we can see that... The rotation angles of each joint can be obtained through forward kinematics, then: ； Then the end-effector pose of the i-th rotating robotic arm can be obtained. : ； Depend on By combining inverse kinematics, the angles of rotation required for each joint relative to its initial position in the i-th rotation can be obtained. B. and ; Rotate clockwise, at this time: ； Similarly, the answer can be found; C、 ； If the height difference is within the allowable error range, stop the rotation, record the rotation angle of each joint at this time, and use forward kinematics to obtain the actual pose of the actuator end effector at this time. .

11. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that: After adjusting the height difference of the pipe segments, translate the pipe segments along the negative z-axis of {seg1} to make the arc edge of the pipe segment to be assembled fit with that of the already assembled pipe segment, so that... Within the allowable error range, assume each downward translation... Then, after i translations, the translation amount relative to the initial position is ,set up Let be the coordinate transformation matrix between the i-th translation of the segment to be assembled and its initial position. Then: ； ； but: ； right By performing inverse kinematics solutions, the motion offset required for the i-th translation of the robot arm's degree of freedom relative to its initial translation position along the negative z-axis can be calculated. The segment moves continuously along the negative z-axis of {seg1}. Stop translation when the error is within the allowable range.

12. The automated assembly method for tunnel boring machine segments based on a line laser sensor according to claim 1, characterized in that, The method for reducing the straight edge gap between the segments to be assembled and the already assembled segments includes the following steps: A. After the segment is translated along the negative z-axis of {seg1}, the arc-shaped side of the segment to be assembled is fitted with the segment already assembled. At this time, the segment needs to be rotated around the axis of the inner surface of the segment so that the gap between the straight edge of the segment to be assembled and the segment already assembled is continuously reduced. When the gap between the two straight edges is within the allowable error range, the rotation is stopped and the segment assembly is completed. B. Rotational pose calculation: In the {seg1} coordinate system, by , , The coordinates of the center of the circle containing the arc edge of the segment to be assembled can be determined. Let the center of the circle be... Establish a coordinate system {seg0} with O as the origin, whose x, y, and z axes are aligned with the direction of {seg1}. Then, the transformation matrix from {seg0} to {seg1} is... for: ； in , I is the identity matrix; Looking from the positive x-axis of {seg0} to the negative x-axis, the gap between the segment to be assembled and the straight edge of the already assembled segment can be reduced by rotating the segment to be assembled counterclockwise around the x-axis of {seg0}. Assume each rotation Then, the angle of rotation relative to the initial {seg0} position after the i-th rotation is... ; ； ； Let the position of the robotic arm's end effector after the i-th rotation be... , The pose of the robotic arm's end effector at the end of the translation of the segment along the negative z-axis of {seg1} is given by step four. Since the rotation angles of each joint can be obtained through normal kinematics, then: ； Then the end-effector pose of the i-th rotating robotic arm can be obtained. : ； Depend on By combining inverse kinematics, the angles of rotation required for each joint relative to its initial position in the i-th rotation can be obtained. C. Calculation of straight edge clearance: The laser line of the fourth line laser s4 intersects the straight edges of the segments to be assembled and the assembled segments at E and E'. The laser line of the fifth line laser s5 intersects the straight edges of the segments to be assembled and the assembled segments at D and D'. From the second step, we know that in the {t} coordinate system, the x-axis direction vector of {seg1}... It has been determined that the straight edge of the segment to be assembled is perpendicular to plane ABC: ； in, This is the transformation matrix between the line laser S4 and the coordinate system of the robotic arm's end effector. Let be the transformation matrix between the line laser s5 and the coordinate system of the robotic arm end effector. Both can be obtained through hand-eye calibration between the line laser and the robotic arm end effector. Let gap be the distance between the two straight sides, then: ； when That is, the segment assembly is completed when the gap between the two straight edges is within the allowable error range.

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