Nine-freedom segment erector and segment erection method

Abstract

This invention relates to the field of tunnel construction technology and discloses a nine-degree-of-freedom segment assembly machine and its usage method. The assembly machine includes a gantry structure, translational hydraulic cylinders, a rotation mechanism, a hydraulic motor, lifting cylinders, a lifting beam, a stationary platform, an actuating cylinder group, a moving platform, clamping cylinders, a sensor group, and an electrical and control system. The translational hydraulic cylinders provide one translational degree of freedom, the rotation mechanism provides one rotational degree of freedom, and the two lifting cylinders provide one lifting degree of freedom. The stationary platform, moving platform, and actuating cylinder group constitute a six-degree-of-freedom parallel mechanism, forming a nine-degree-of-freedom motion control system. Its usage method includes installation and calibration, coarse and fine adjustment of position and posture, segment clamping, and assembly. This invention, by combining three-degree-of-freedom coarse adjustment with six-degree-of-freedom fine adjustment, and using closed-loop feedback control with visual sensors, solves the problems of large mechanical backlash interference, large coordinate transformation errors, difficult control, and low efficiency, thus improving assembly accuracy and speed.

Description

Technical Field

[0001] This invention relates to the field of tunnel and underground engineering construction technology, and in particular to a nine-degree-of-freedom segment assembly machine and its usage method. Background Technology

[0002] Shield tunnel boring machines (TBMs), as core equipment for tunnel and underground engineering construction, have been widely used in railway, highway, subway, and water conservancy projects. Segment assemblies are one of the key supporting equipment for TBMs, used to assemble precast concrete segments into tunnel lining rings according to the design sequence. Their assembly accuracy and efficiency directly affect the tunnel's forming quality, waterproofing performance, and construction progress.

[0003] Currently, most common tunnel segment assembly machines employ a series-type multi-degree-of-freedom robotic arm structure. For example, segment positioning is achieved through three coarse adjustment degrees of freedom (translation, rotation, and lifting) combined with a passive compliant mechanism at the end effector. With the increasing demands for automation and intelligence in tunnel construction, some high-end assembly machines are beginning to incorporate visual sensors and parallel micro-motion mechanisms, attempting to achieve automatic segment identification and posture adjustment. However, existing technologies still face the following prominent problems in intelligent assembly processes: 1. Significant impact of mechanical backlash: Manufacturing and assembly backlashes are unavoidable in various moving parts of the assembly machine (such as hinge holes, guide rail pairs, gear ring meshing, etc.). Under heavy-load conditions, these backlashes can cause nonlinear deviations between the actual and theoretical poses of the end effector, severely interfering with accurate alignment under vision guidance.

[0004] 2. Large hand-eye coordinate system transformation error: Vision sensors (cameras, laser sensors) are usually installed on the end effector, requiring the establishment of a transformation relationship between the sensor coordinate system and the coordinate systems of each moving part. Due to insufficient structural rigidity of existing assembly machines, easy deformation of sensor supports, and simple calibration methods, the hand-eye calibration accuracy is low, and the coordinate transformation error can reach the centimeter level, making it difficult to meet the millimeter-level accuracy requirements for segment assembly.

[0005] 3. Difficulty in high-precision motion control: Traditional assembly machines rely solely on coarse-degree-of-freedom adjustments (translation, rotation, and lifting) for positioning, lacking multi-degree-of-freedom fine-tuning capabilities at the end. Even with the introduction of a six-degree-of-freedom parallel platform, issues such as low accuracy of hydraulic cylinder displacement detection, slow control valve response, and imperfect closed-loop control strategies often result in large dynamic positioning errors and long adjustment times.

[0006] 4. Low overall assembly efficiency: In the existing intelligent assembly process, there is a lack of coordinated optimization in the visual recognition, pose calculation and motion execution stages, which often requires repeated measurement and adjustment. At the same time, the allocation of margin between coarse adjustment and fine adjustment is unreasonable, resulting in excessive or insufficient travel in the fine adjustment stage and a long overall assembly cycle.

[0007] To address the aforementioned issues, some existing technologies have attempted to improve the situation by increasing machining precision, employing high-resolution encoders, and optimizing control algorithms. However, these solutions either significantly increase manufacturing costs or lack reliability in the harsh environment of tunnels. Summary of the Invention

[0008] The purpose of this invention is to provide a nine-degree-of-freedom segment assembly machine and segment assembly method to solve the above-mentioned problems. It can take into account mechanical backlash compensation, precise hand-eye coordinate conversion, high-precision motion control, and efficient assembly process.

[0009] The present invention achieves the above objectives through the following technical solutions: A nine-degree-of-freedom segment assembly machine, including a gantry structure; A translational hydraulic cylinder installed on the gantry structure; A rotary mechanism connected to the end of the translational hydraulic cylinder, the rotary mechanism being driven to rotate by a hydraulic motor; Two lifting cylinders are connected to the rotary mechanism; A lifting crossbeam installed at the lower end of the two lifting cylinders; A stationary platform fixed at the lower end of the lifting beam; The moving platform is connected to the static platform via an actuating cylinder assembly; A clamping cylinder installed at the bottom of the moving platform to clamp the pipe segments; And sensor arrays and electrical and control systems; The translational hydraulic cylinder and the lifting hydraulic cylinder have built-in displacement sensors, and the output shaft of the hydraulic motor has an encoder. The sensor group is installed on the moving platform or the grabbing head and is used to measure the position and orientation of the tube segments; The electrical and control system is electrically connected to the sensor group, translation hydraulic cylinder, rotary mechanism, lifting cylinder and actuation cylinder group respectively, and is used to receive measurement data and control the action of each actuator in a closed loop. The translational hydraulic cylinder provides one translational degree of freedom, the rotary mechanism provides one rotational degree of freedom, the two lifting cylinders provide one lifting degree of freedom, and the static platform, the dynamic platform, and the actuating cylinder group together constitute a six-degree-of-freedom parallel mechanism, thereby forming a nine-degree-of-freedom motion control as a whole.

[0010] Preferably, the gantry structure is I-shaped, with crossbeams symmetrically arranged on both sides, and guide rail grooves are machined on the sides of the crossbeams.

[0011] Preferably, one end of the translational hydraulic cylinder is hinged to the cylinder mounting base on the crossbeam, and the other end is hinged to the outer shell of the rotary mechanism; the axis of the translational hydraulic cylinder is parallel to the working plane of the guide rail groove.

[0012] Preferably, the rotary mechanism includes a fixed part and a rotating part, and a hydraulic motor with a brake that can rotate in both directions is installed on the fixed part.

[0013] Preferably, a gear is mounted on the output shaft of the hydraulic motor; a large gear ring is provided in the rotating part of the rotary mechanism, and the large gear ring meshes with the gear.

[0014] Preferably, the two lifting cylinders are symmetrically mounted on the rotating part of the slewing mechanism and are equipped with guide sleeves; the moving end of the lifting cylinder is hinged to the lifting beam.

[0015] Preferably, the actuating cylinder assembly includes an upper Hooke hinge, a cylinder body, and an upper Hooke hinge. The stationary platform has six protrusions for installing the upper Hooke hinge, and the moving platform has six protrusions for installing the lower Hooke hinge. The cylinder body of the actuating cylinder assembly is installed between the upper and lower corresponding upper and lower Hooke hinges in each group.

[0016] Preferably, the cylinder body has a built-in displacement sensor and is equipped with a proportional valve or servo valve to form a closed-loop feedback control.

[0017] Preferably, the sensor group includes a binocular structured light camera, a binocular camera and a line laser sensor. The field of view of the binocular structured light camera or the binocular camera can simultaneously cover the two side lines of the segment to be assembled and the contact longitudinal seam of the adjacent assembled segment at the assembly station, and can also cover the screw holes and segment gripping holes.

[0018] In addition, the present invention also provides a method for using the above-mentioned nine-degree-of-freedom segment assembly machine, comprising the following steps: S1: Install the nine-degree-of-freedom segment assembly machine and connect the gantry structure to the TBM main machine's sub-beam; S2: Perform hand-eye coordinate system calibration; S3: Move to the segment grabbing position, the vision sensor collects the image of the entire segment, the host computer calculates the grabbing hole position, and makes preliminary adjustments through translation hydraulic cylinder, lifting hydraulic cylinder and hydraulic motor, reserving the first displacement margin and the first angle margin. Then, measure the actual displacement and rotation angle, convert the difference into the target value of the six sets of action cylinders in the static platform coordinate system, and control the six sets of action cylinders to move to the designated position by the PLC to form a closed loop feedback; S4: Segment clamping; S5: Segment assembly coarse adjustment. The assembly machine moves close to the assembled segment. The vision sensor and line laser sensor collect data. The host computer calculates the positional relationship between the segment to be assembled and the assembled segment, performs coordinate transformation, and controls the movement of the translation hydraulic cylinder, lifting hydraulic cylinder and hydraulic motor to reserve a second displacement margin and a second angle margin between the segment to be assembled and the target position. The second displacement margin is greater than the first displacement margin. S6: Segment assembly fine adjustment, the position relationship is measured and calculated again by the sensor to obtain the position change in the static platform coordinate system, and then the action amount of the six sets of hydraulic cylinders is calculated. The PLC control valve drives the hydraulic cylinders to perform the action, so that the segment to be assembled reaches the specified position until the position error meets the assembly requirements. S7: Complete the segment assembly.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention employs a technical solution combining a three-degree-of-freedom large-stroke coarse adjustment mechanism with a six-degree-of-freedom parallel micro-motion fine adjustment mechanism. The translational hydraulic cylinder, rotation mechanism, and lifting cylinder provide a wide range of position adjustment capabilities, while the six-degree-of-freedom parallel mechanism enables precise micro-adjustment of the end-effector's posture. The coarse and fine adjustments work together to ensure the large-stroke motion requirements during the gripping and assembly process, while also compensating for errors such as mechanical clearance and structural deformation during the fine adjustment stage. This results in millimeter-level precision in segment assembly, significantly improving the forming quality of the tunnel lining.

[0020] 2. This invention integrates a binocular structured light camera, a binocular camera, and a line laser sensor onto a moving platform or lifting head, enabling simultaneous coverage of the two side lines of the segment to be assembled, the contact seams of adjacent assembled segments, screw holes, and segment gripping holes. By acquiring segment pose information through a vision sensor and combining it with image processing and coordinate transformation by a host computer, the position of the gripping holes and the assembly pose relationship are automatically calculated, achieving automatic identification of segment features and automatic pose calculation. Combined with hand-eye coordinate system calibration and closed-loop feedback control, manual intervention is significantly reduced, improving the automation and intelligence level of the assembly process.

[0021] 3. In this invention, the translational hydraulic cylinder, lifting cylinder, and actuation cylinder all have built-in high-precision displacement sensors, and the hydraulic motor output shaft is equipped with a high-precision encoder. All actuators are equipped with proportional valves or servo valves, forming a fully closed-loop feedback control. During the segment grabbing stage, a first displacement margin and a first angular margin are reserved, which are precisely aligned by a parallel mechanism to compensate for the clearance and error of the coarse adjustment mechanism. During the assembly coarse adjustment stage, a second displacement margin is reserved, and this second displacement margin is greater than the first displacement margin, providing sufficient safety adjustment space for the fine adjustment stage. This control strategy of tiered margin reservation and tiered error compensation effectively overcomes the influence of adverse factors such as mechanical clearance, structural deformation, and sensor bracket deformation on assembly accuracy, ensuring the system's control stability under heavy loads and harsh tunnel environments.

[0022] 4. This invention employs a combined coarse and fine-tuning assembly process design. Both the grasping and assembly stages utilize a two-step strategy of "large-stroke coarse adjustment + parallel fine-tuning," avoiding the drawbacks of traditional assembly machines that require multiple repeated measurements and adjustments. The coarse-tuning mechanism quickly transports the segment to the vicinity of the target pose, while the parallel mechanism completes precise alignment in one go, optimizing the assembly cycle. Simultaneously, the vision sensor can adapt to different segment types and assembly conditions. Adjustments via a host computer algorithm can accommodate segments of different specifications without requiring modifications to the mechanical structure, demonstrating excellent engineering adaptability.

[0023] 5. The gantry structure of this invention is I-shaped, with symmetrical crossbeams on both sides. The lifting crossbeams are made of steel, and the key moving parts adopt a high-precision fit clearance design to ensure the overall structural rigidity. The clamping cylinder has a built-in pressure sensor, and the PLC determines whether the segments are clamped properly by reading the pressure data. Clamping is only considered complete when the pressure reaches a set threshold, preventing the segments from falling off during transportation. The control system has complete logic interlocking and error handling functions, ensuring the safety and reliability of the assembly operation. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a nine-degree-of-freedom segment assembly machine according to the present invention.

[0026] Figure 2 This is a partially enlarged view of a nine-degree-of-freedom segment assembly machine according to the present invention. Figure 3 This is a flowchart illustrating the usage method of a nine-degree-of-freedom segment assembly machine as described in this invention.

[0027] The annotations in the attached figures are explained as follows: 1. Gantry structure; 2. Translation hydraulic cylinder; 3. Rotation mechanism; 4. Hydraulic motor; 5. Lifting cylinder; 6. Lifting beam; 7. Stationary platform; 8. Actuating cylinder assembly; 81. Upper Hooke hinge; 82. Cylinder body; 83. Lower Hooke hinge; 9. Moving platform; 10. Clamping cylinder; 11. Sensor assembly; 12. Grab head; 13. Hydraulic oil supply unit connection; 14. Electrical and control system. Detailed Implementation

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood through the specific circumstances.

[0030] The present invention will be further described below with reference to the accompanying drawings: Example 1

[0031] like Figures 1-2 As shown, this embodiment provides a nine-degree-of-freedom segment assembly machine. The assembly machine mainly includes: a gantry structure 1, a translational hydraulic cylinder 2, a rotation mechanism 3, a hydraulic motor 4, a lifting cylinder 5, a lifting beam 6, a static platform 7, an actuating cylinder group 8, a moving platform 9, a clamping cylinder 10, a sensor group 11, and an electrical and control system 14.

[0032] Specifically, the gantry structure 1 is I-shaped and is used for fixed connection with the sub-beams of the shield tunneling TBM main unit. Symmetrical crossbeams are provided on both sides of the structure, and high-precision guide rail grooves are machined on the sides of the crossbeams. The flatness of the working plane of the guide rail groove is preferably no more than 0.03 mm to ensure the guiding accuracy of the translational movement.

[0033] The translational hydraulic cylinder 2 is mounted on the gantry structure 1. One end (e.g., the rod end) is hinged to the cylinder mounting base on the crossbeam, and the other end (the rodless cavity side) is hinged to the housing of the rotary mechanism 3. The axis of the translational hydraulic cylinder 2 is parallel to the working plane of the guide rail groove, and the parallelism is preferably no more than 0.05 mm. The translational hydraulic cylinder 2 has a built-in displacement sensor (such as an LVDT), with a full-stroke displacement error of less than 1 mm, and is equipped with a proportional valve or servo valve to provide high-precision translational freedom.

[0034] The rotary mechanism 3 includes a fixed part and a rotating part. The fixed part is connected to the end of the translational hydraulic cylinder 2. A reversible hydraulic motor 4 with a braking function is mounted on the fixed part. A gear is mounted on the output shaft of the hydraulic motor 4, which meshes with a large gear ring inside the rotating part of the rotary mechanism 3, driving the rotating part to rotate. The output shaft of the hydraulic motor 4 is equipped with a high-precision encoder (accuracy not less than 0.05°) and a proportional valve or servo valve to provide a controllable degree of rotational freedom.

[0035] Two lifting cylinders 5 are symmetrically mounted on the rotating part of the slewing mechanism 3, and are equipped with guide sleeves to enhance stability. The moving end of the lifting cylinder 5 is hinged to the lifting beam 6. Each lifting cylinder 5 has a built-in displacement sensor (such as an LVDT), with a full-stroke displacement error of less than 1mm, and is equipped with a proportional valve or servo valve. The two lifting cylinders 5 move synchronously, providing a single degree of freedom for lifting.

[0036] A stationary platform 7 is fixedly connected to the lower end of the lifting beam 6. The stationary platform 7 and the moving platform 9 are connected by an actuating cylinder assembly 8. Specifically, the actuating cylinder assembly 8 includes an upper Hooke hinge 81, a cylinder body 82, and an upper Hooke hinge 83. The stationary platform 7 has six bosses for mounting the upper Hooke hinge 81, and the moving platform 9 has six bosses for mounting the lower Hooke hinge 83. The cylinder body 82 of the actuating cylinder assembly 8 is installed between the corresponding upper and lower Hooke hinges 81 and lower Hooke hinge 83 in each set. Each cylinder body 82 has a built-in high-precision displacement sensor (such as an LVDT), with a full-stroke displacement error of less than 0.01mm, and is equipped with a proportional valve or servo valve to form a closed-loop feedback control. Thus, the stationary platform 7, the moving platform 9, and the actuating cylinder assembly 8 together constitute a six-degree-of-freedom parallel mechanism.

[0037] A clamping cylinder 10 is installed at the lower part of the moving platform 9 for clamping and releasing the tube segments. The clamping cylinder 10 has a built-in pressure sensor to determine whether the clamping force reaches a threshold, ensuring safe gripping. The clamping cylinder 10 and the moving platform 9 form a gripping head 12. A forward-tilting gantry-type mounting frame is installed on the upper surface of the moving platform 9, and a sensor group 11 is installed on the mounting frame for measuring the position and orientation of the tube segments. In this embodiment, the sensor group 11 includes a binocular structured light camera, a binocular camera, and a line laser sensor. At the assembly station, the field of view of the binocular structured light camera or the binocular camera can simultaneously cover the two side lines of the tube segment to be assembled, the contact longitudinal seam of adjacent assembled tube segments, screw holes, and tube segment gripping holes. The sensor fixing bracket has high rigidity, and the deformation during operation is controlled within 0.01mm to ensure measurement accuracy.

[0038] The electrical and control system 14 includes a PLC and a host computer, which are respectively connected to the sensor group 11, the displacement sensor and proportional valve / servo valve of the translational hydraulic cylinder 2, the encoder and proportional valve / servo valve of the hydraulic motor 4 of the rotary mechanism 3, the displacement sensor and proportional valve / servo valve of the lifting cylinder 5, and the displacement sensor and proportional valve / servo valve of the actuation cylinder group 8. This system receives data measured by the sensors, performs calculations according to a preset algorithm, and then performs closed-loop control to precisely control the movements of each actuator (cylinder, motor).

[0039] The above structures together constitute the nine-degree-of-freedom segment assembly machine of the present invention: the translational hydraulic cylinder 2 provides a translational degree of freedom, the rotary mechanism 3 provides a rotary degree of freedom, the two lifting cylinders 5 provide a lifting degree of freedom, and the six-degree-of-freedom parallel mechanism composed of the static platform 7, the moving platform 9 and the actuating cylinder group 8 provides the remaining six degrees of freedom (three translations and three rotations), thus forming a nine-degree-of-freedom motion control as a whole. Example 2

[0040] This embodiment will describe in detail the method of assembling tunnel segments using the aforementioned nine-degree-of-freedom segment assemblies. For example... Figure 3 As shown, the method mainly includes the following steps: Step S1: Installation of the nine-degree-of-freedom segment assembly machine.

[0041] First, firmly connect the gantry structure 1 to the sub-beam of the shield TBM main unit. Complete the assembly of the gantry structure 1, translation hydraulic cylinder 2, slewing mechanism 3, hydraulic motor 4, lifting cylinder 5, lifting crossbeam 6, stationary platform 7, actuation cylinder group 8, moving platform 9, clamping cylinder 10, and sensor group 11 described in Embodiment 1, and connect all hydraulic actuators to the hydraulic oil supply unit 13, and electrically connect all sensors and electrical components to the electrical and control system 14.

[0042] Step S2: Perform hand-eye coordinate system calibration.

[0043] Before starting automatic assembly, coordinate system calibration is required. This includes: first, calibrating the coordinate system of the translation hydraulic cylinder 2 (i.e., the coarse adjustment coordinate system) and the vision sensor coordinate system; then, calibrating the coordinate system of the static platform 7 (i.e., the base coordinate system of the fine adjustment parallel mechanism) and the vision sensor coordinate system. After calibration, the segment pose information measured by the vision sensor can be accurately converted to the control coordinate system of each actuator.

[0044] Step S3: Move to the segment grabbing position and grab it precisely.

[0045] The assembly machine moves to the segment grabbing station according to a preset program. At this time, a vision sensor (such as a binocular camera) acquires an image of the segment to be grabbed and transmits it to the host computer. The host computer calculates the position of the segment grabbing hole (in the visual coordinate system) using an image processing algorithm. Then, the control system drives the translation hydraulic cylinder 2, the lifting cylinder 5, and the hydraulic motor 4 for preliminary adjustment, so that the two moving ends of the clamping cylinder 10 of the grabbing head 12 approach the grabbing hole on the tunnel segment. This step requires reserving a first displacement margin (e.g., 4 cm) and a first angle margin (e.g., 0.5°) to allow space for subsequent fine-tuning.

[0046] Next, the actual displacement and rotation angle are measured using built-in displacement sensors and encoders, and the difference between the actual displacement and the target pose is calculated. The host computer converts this difference into the target extension and retraction of the six sets of hydraulic cylinders in the coordinate system of the static platform 7. The PLC drives the six sets of hydraulic cylinders 8 to move precisely to the designated position by controlling proportional valves or servo valves, forming a closed-loop feedback, thereby compensating for the backlash and error of the coarse adjustment mechanism and achieving precise alignment between the gripping head 12 and the gripping hole.

[0047] Step S4: Clamp the segments.

[0048] After the lifting head 12 is aligned, the PLC first controls the lifting cylinder 5 to press down a specific distance, so that the lifting head 12 contacts the tube segment. Then, it controls the clamping cylinder 10 to clamp the tube segment. When the pressure sensor built into the clamping cylinder 10 detects that the pressure has reached the preset safety threshold, it determines that the clamping action is complete, ensuring that the tube segment will not fall off during subsequent handling.

[0049] Step S5: Rough adjustment of segment assembly.

[0050] After clamping the segments, the assembly machine moves along a preset path, transporting the segments to the target installation position close to the already assembled segments. At this position, vision sensors (binocular camera and line laser sensor) simultaneously acquire feature information such as the edges, longitudinal seams, and bolt holes of the segment to be assembled and the adjacent already assembled segments. The host computer calculates the relative pose relationship between the segment to be assembled and the already assembled segments.

[0051] After coordinate transformation, the control system drives the translation hydraulic cylinder 2, lifting cylinder 5, and hydraulic motor 4 to move again, performing a large-scale coarse adjustment to make the segments to be assembled quickly approach the target position. This step requires reserving a second displacement margin (e.g., 5cm) and a second angle margin (e.g., 0.5°), where the second displacement margin is greater than the first displacement margin (4cm), to provide sufficient safety adjustment space for the fine-tuning stage.

[0052] Step S6: Segment assembly and fine-tuning.

[0053] After the coarse adjustment is completed, the fine adjustment stage begins. Sensor group 11 measures the precise positional relationship between the segment to be assembled and the already assembled segment again. The host computer calculates the required position and attitude changes in the coordinate system of the static platform 7, and then solves for the precise displacement of each of the six sets of hydraulic cylinders 8.

[0054] Based on the calculation results, the PLC sends commands to the proportional valves or servo valves controlling the six sets of hydraulic cylinders 8, driving the cylinders to perform micro-motion. Since the hydraulic cylinder group 8 constitutes a six-degree-of-freedom parallel mechanism, it can achieve millimeter-level or even higher precision position adjustment. The control system performs real-time closed-loop feedback control until the position error meets the assembly requirements (e.g., joint width, flatness, bolt hole alignment, etc. are all qualified).

[0055] Step S7: Complete the segment assembly.

[0056] Once the segment to be assembled reaches the precise target position, the control system executes segment positioning and fixing actions (such as controlling the lifting force and operating bolt installation). Subsequently, the clamping cylinder 10 releases, and the lifting head 12 disengages from the segment. The assembly machine can then return to the gripping station, ready to begin the assembly cycle of the next segment.

[0057] Step S8: Cyclic operation.

[0058] Repeat steps S3 to S7 until the entire lining ring is assembled.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0060] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A nine-degree-of-freedom segment assembly machine, characterized in that, include: gantry structure (1); Translational hydraulic cylinder (2) installed on the gantry structure (1); A rotary mechanism (3) is connected to the end of the translational hydraulic cylinder (2), and the rotary mechanism (3) is driven to rotate by a hydraulic motor (4); Two lifting cylinders (5) are connected to the rotary mechanism (3); Lifting crossbeams (6) are installed at the lower ends of the two lifting cylinders (5); The stationary platform (7) is fixed at the lower end of the lifting beam (6); The moving platform (9) is connected to the stationary platform (7) via the hydraulic cylinder assembly (8). A clamping cylinder (10) installed on the lower part of the moving platform (9) for clamping the pipe segments. And sensor array (11) and electrical and control system (14); The translational hydraulic cylinder (2) and the lifting cylinder (5) have built-in displacement sensors, and the output shaft of the hydraulic motor (4) has an encoder. The sensor group (11) is mounted on the moving platform (9) and is used to measure the position and orientation of the tube segments; The electrical and control system (14) is electrically connected to the sensor group (11), translation hydraulic cylinder (2), rotation mechanism (3), lifting cylinder (5) and action cylinder group (8) respectively, and is used to receive measurement data and control the action of each actuator in a closed loop. Among them, the translational hydraulic cylinder (2) provides a translational degree of freedom, the rotary mechanism (3) provides a rotary degree of freedom, the two lifting cylinders (5) provide a lifting degree of freedom, and the static platform (7), the moving platform (9) and the actuation cylinder group (8) together constitute a six-degree-of-freedom parallel mechanism, thereby forming a nine-degree-of-freedom motion control as a whole.

2. The nine-degree-of-freedom segment assembly machine according to claim 1, characterized in that: The gantry structure (1) is I-shaped, with crossbeams symmetrically arranged on both sides, and guide rail grooves are machined on the sides of the crossbeams.

3. The nine-degree-of-freedom segment assembly machine according to claim 2, characterized in that: One end of the translational hydraulic cylinder (2) is hinged to the cylinder mounting base on the crossbeam, and the other end is hinged to the outer shell of the rotary mechanism (3); the axis of the translational hydraulic cylinder (2) is parallel to the working plane of the guide rail groove.

4. The nine-degree-of-freedom segment assembly machine according to claim 1, characterized in that: The rotary mechanism (3) includes a fixed part and a rotating part, and a hydraulic motor (4) capable of reversing forward and reverse rotation with a brake is installed on the fixed part.

5. A nine-degree-of-freedom segment assembly machine according to claim 4, characterized in that: The output shaft of the hydraulic motor (4) is equipped with a gear; the rotating part of the rotary mechanism (3) is provided with a large gear ring, which meshes with the gear.

6. A nine-degree-of-freedom segment assembly machine according to claim 4, characterized in that: The two lifting cylinders (5) are symmetrically installed on the rotating part of the rotary mechanism (3) and are equipped with guide sleeves; the moving end of the lifting cylinder (5) is hinged to the lifting beam (6).

7. A nine-degree-of-freedom segment assembly machine according to claim 1, characterized in that: The actuating cylinder assembly (8) includes an upper Hooke hinge (81), a cylinder body (82), and an upper Hooke hinge (83). The stationary platform (7) has six bosses for installing the upper Hooke hinge (81), and the moving platform (9) has six bosses for installing the lower Hooke hinge (83). The cylinder body (82) of the actuating cylinder assembly (8) is installed between the upper Hooke hinge (81) and the lower Hooke hinge (83) of each group.

8. A nine-degree-of-freedom segment assembly machine according to claim 7, characterized in that: The cylinder body (82) has a built-in displacement sensor and is equipped with a proportional valve or servo valve to form a closed-loop feedback control.

9. A nine-degree-of-freedom segment assembly machine according to claim 1, characterized in that: The sensor group (11) includes a binocular structured light camera, a binocular camera and a line laser sensor (area laser sensor). The field of view of the binocular structured light camera or the binocular camera can simultaneously cover the two side lines of the tube segment to be assembled and the contact longitudinal seam of the adjacent assembled tube segment at the assembly station, and can also cover the screw holes and the tube segment gripping holes.

10. A segment assembly method based on the nine-degree-of-freedom segment assembly machine according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Install the nine-degree-of-freedom segment assembly machine and connect the gantry structure (1) to the shield TBM host's sub-beam; S2: Perform hand-eye coordinate system calibration; S3: Move to the segment grabbing position, the vision sensor collects the image of the entire segment, the host computer calculates the grabbing hole position, and makes preliminary adjustments through translation hydraulic cylinder, lifting hydraulic cylinder and hydraulic motor, reserving the first displacement margin and the first angle margin. Then, measure the actual displacement and rotation angle, convert the difference into the target value of the six sets of action cylinders in the static platform coordinate system, and control the six sets of action cylinders to move to the designated position by the PLC to form a closed loop feedback; S4: Segment clamping; S5: Segment assembly coarse adjustment. The assembly machine moves close to the assembled segment. The vision sensor and line laser sensor collect data. The host computer calculates the positional relationship between the segment to be assembled and the assembled segment, performs coordinate transformation, and controls the movement of the translation hydraulic cylinder, lifting hydraulic cylinder and hydraulic motor to reserve a second displacement margin and a second angle margin between the segment to be assembled and the target position. The second displacement margin is greater than the first displacement margin. S6: Segment assembly fine adjustment, the position relationship is measured and calculated again by the sensor to obtain the position change in the static platform coordinate system, and then the action amount of the six sets of hydraulic cylinders is calculated. The PLC control valve drives the hydraulic cylinders to perform the action, so that the segment to be assembled reaches the specified position until the position error meets the assembly requirements. S7: Complete the segment assembly.

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