An automated assembly system for tunnel segment bolts and its automated assembly method

Abstract

This invention discloses an automatic assembly system for tunnel segment bolts and its automated assembly method. The system includes a multi-degree-of-freedom robotic arm, with a rotary storage unit connected to the actuator of the robotic arm. The rotary storage unit includes a rotating device, with a bolt storage device connected to its front side and a nut storage device connected to its rear side. The bolt storage device contains several bolt storage compartments arranged in a ring, and the nut storage device contains several nut storage compartments arranged in a ring, with each nut storage compartment corresponding to a bolt storage compartment. A tightening mechanism and a vision device, which cooperate with the bolt storage compartments, are located at the front end of the storage mechanism's outer shell. The actuator of the multi-degree-of-freedom robotic arm is equipped with an axial pushing mechanism that extends into the nut storage compartments. The multi-degree-of-freedom robotic arm, the axial pushing mechanism, the rotating device, and the vision device are all connected to a control system. This invention features a compact structure and flexible operation, enabling efficient and stable bolt assembly.

Description

Technical Field

[0001] This invention relates to the field of tunnel segment assembly technology, and in particular to an automatic assembly system for tunnel segment bolts and its automated assembly method. Background Technology

[0002] Tunnel lining is composed of several segments connected by bolts to form a whole. Bolts are the only component connecting the segments and the most important constraint, so the assembly of bolts plays an important role in the tight connection of the segments.

[0003] As a crucial component of tunnel boring machines (TBMs), segment assemblers play a vital role in tunnel construction. Their efficiency and operational quality directly impact the progress, quality, and lifespan of the tunnel. The segment assembler typically performs procedures such as clamping, moving, rotating, and positioning the segments, as well as bolting them together.

[0004] Traditional bolt assembly is mainly done manually, which has the following drawbacks:

[0005] (1) The diameter of the tunnel boring machine used for urban subway construction is generally around 6.2-6.4m, the outer diameter of the segment is 6.0m, the tunnel diameter is 5.4m, and the assembly time of one ring is generally between 30 and 60 minutes. It takes a lot of time and has low efficiency, which reduces the working efficiency of the segment assembly machine and affects the progress of tunnel construction. To complete the installation of one ring of segments, 16 circumferential connecting bolts and 12 axial connecting bolts are required. When the construction personnel are assembling the bolts, the number of bolts they can carry is limited each time, and they need to make multiple trips to complete the connection of one ring of bolts, which takes a long time and reduces the working efficiency of bolt assembly.

[0006] (2) After the segments are installed in place, the construction personnel first tighten the circumferential connecting bolts, and then tighten the axial connecting bolts in sequence. When assembling the bolts, first put the bolts into the holes where the bolts need to be assembled and put on the nuts, but do not tighten them temporarily. Extend the corresponding push cylinder and press the segments that have been in place. In order to ensure that the nuts are tightened in place, the construction personnel will tighten the nuts with a wrench. During the tightening process, since it is impossible to accurately judge the torque of the nuts, they may be too tight or too loose. Too tight may damage the segments, and too loose will affect the bolt assembly accuracy and reduce the load-bearing capacity. This will cause too much deviation for the segment installation of the entire tunnel. When assembling, the nuts must be tightened just right. Otherwise, it will reduce the quality of the segment assembly machine operation, thereby affecting the quality and service life of the tunnel construction. In order to reduce the joints, the nuts should be tightened and reinforced. Generally speaking, the tightening and reinforcement of the nuts need to be repeated many times. The bolt assembly process is complicated, the assembly quality cannot be guaranteed, and it leaves potential safety hazards for the tunnel.

[0007] (3) Due to the small area of ​​the segment installation operation and the many unpredictable external factors, there are potential hazards that may affect the personal safety of construction personnel. Therefore, construction personnel must be familiar with the safe operating procedures and pay attention to the coordination between operators. Since the segment assembly machine will also generate a lot of noise during construction, the dust pollution at the construction site is serious and the working environment is harsh, which greatly affects the health of the workers.

[0008] A search revealed that Chinese invention patent application CN 113250718 A, published on August 13, 2021, discloses an intelligent segment assembly system and method based on automatic cruise. The system includes an internal walking mechanism, a movable disk fixed to the periphery of the internal walking mechanism, a rotating mechanism meshing with the movable disk, and a robotic arm operating platform fixed to the rotating mechanism. The internal walking mechanism includes a walking mechanism, a data processing mechanism mounted on the walking mechanism, a walking beam, and a hydraulic cylinder for driving the walking mechanism along the walking beam. The robotic arm operating platform is equipped with an image recognition mechanism and a robotic arm. While this invention patent provides a method for automatically assembling segment bolts, it only discloses a double-headed robotic arm for bolt installation and tightening. The robotic arm uses a hexagonal groove on a three-jawed manipulator to grasp the bolt and insert it into the bolt hole. After the bolt is installed, the robotic arm with a pneumatic wrench tightens the nut. It does not cover the specific details of automatic bolt and nut installation.

[0009] Chinese invention patent application CN 114161130 A, published on March 11, 2022, discloses an automatic installation and tightening system for tunnel segment bolts in a tunnel boring machine. The system includes a feeding tray, a traveling system, a bolt installation system, a nut tightening system, and a PLC control system. The traveling system, bolt installation system, and nut tightening system are all communicatively connected to the PLC control system. While this invention discloses a relatively specific automatic assembly structure for tunnel segment bolts, it requires two robotic arms to separately grasp the nut and bolt for each bolt installation, followed by positioning and assembly operations. This not only results in redundant movements and low reliability but also low efficiency. Summary of the Invention

[0010] To address the shortcomings in the aforementioned background technology, this invention proposes an automatic assembly system for tunnel segment bolts and its automated assembly method, which solves the technical problems of low reliability and efficiency in the bolt assembly system for tunnel segments.

[0011] The technical solution of this application is as follows:

[0012] An automated assembly system for tunnel segment bolts includes a multi-degree-of-freedom robotic arm. The actuator of the multi-degree-of-freedom robotic arm is connected to a rotary storage unit. The rotary storage unit includes a storage mechanism housing, inside which a rotary device is installed. The front of the rotary device is connected to a bolt storage device, and the rear is connected to a nut storage device. The bolt storage device contains several bolt storage compartments arranged in a ring, and the nut storage device contains several nut storage compartments arranged in a ring. Each nut storage compartment corresponds to a bolt storage compartment. The front end of the storage mechanism housing is equipped with a tightening mechanism and a vision device that cooperate with the bolt storage compartments. The actuator of the multi-degree-of-freedom robotic arm is equipped with an axial pushing mechanism that can extend into the nut storage compartments. The multi-degree-of-freedom robotic arm, the axial pushing mechanism, the rotary device, and the vision device are all connected to a control system.

[0013] Furthermore, the nut storage device includes a rotary table that is ball-jointed to a multi-degree-of-freedom robotic arm, the nut storage chamber is disposed on the rotary table, a nut fixing assembly is disposed inside the nut storage chamber, and the axial pushing mechanism is in abutting engagement with the nut fixing assembly.

[0014] Furthermore, the nut fixing assembly includes a fixed disc slidably disposed in the nut storage chamber, a fixed shaft is provided on the inner side of the fixed disc, the nut to be installed is inserted on the fixed shaft, and the fixed shaft is axially aligned with the bolt to be installed in the bolt storage chamber.

[0015] Furthermore, a rubber air bladder is provided on the outer circumferential surface of the fixed disc, and the rubber air bladder slides in contact with the inner wall of the nut storage compartment and the inner wall of the bolt storage compartment.

[0016] Furthermore, the bolt storage compartment is provided with a sliding groove, and a pulley is provided in cooperation with the sliding groove. The pulley is connected to a bolt positioning connector, and an electric gripper is provided on the bolt positioning connector to fix the bolt to be installed. The electric gripper is connected to the control system.

[0017] Furthermore, the tightening mechanism includes a clamping and positioning device driven by a rotary drive device. The clamping and positioning device includes at least two electrically driven clamping blades disposed in the groove. An infrared sensor is disposed on the electrically driven clamping blades. When the infrared sensor detects the nut, the control system controls the electrically driven clamping blades to extend radially to clamp the nut, and then controls the rotary drive device to rotate. A pressure sensor connected to the control system is disposed between the front sidewall of the groove and the clamping and positioning device.

[0018] Furthermore, the axial pushing mechanism includes a pushing cylinder equipped with a displacement sensor. The piston rod end of the pushing cylinder is connected to a pushing device. A protective sleeve is provided outside the rodless chamber. A balancing cylinder is ball-jointed between the protective sleeve and the nut storage device. The pushing device includes a connecting platform hinged to the piston rod end of the pushing cylinder. Several fine-tuning cylinders are hinged to the connecting platform. The piston rod ends of the fine-tuning cylinders are hinged to the same pushing platform. An electromagnet is provided between the pushing platform and the nut storage device. The pushing cylinder, displacement sensor, fine-tuning cylinder, and electromagnet are all connected to the control system.

[0019] Furthermore, the rotary device includes a drive unit connected to the control system. The drive unit meshes with a large gear ring through a transmission unit and a drive gear. The large gear ring is slidably disposed inside the storage mechanism housing. The bolt storage device and the nut storage device are respectively connected to both sides of the large gear ring.

[0020] Furthermore, the multi-degree-of-freedom robotic arm includes a base, the base is connected to a first main arm link via a rotary mechanism, the first main arm link is connected to the execution end via a second main arm link, and servo motors connected to the control system are provided between the rotary mechanism and the first main arm link, between the first main arm link and the second main arm link, and between the second main arm link and the execution end.

[0021] An automated assembly method for tunnel segment bolts, employing the aforementioned automated assembly system for tunnel segment bolts, includes the following steps:

[0022] Step 1: The tunnel segment bolt automatic assembly system moves towards the tail of the shield under the action of the multi-degree-of-freedom robotic arm. The vision device located on the tightening mechanism scans and identifies the surroundings, and transmits the scan information to the background management system through the control system for analysis. It determines the position of the bolt holes of the tunnel segment and obtains the pose of the bolt holes in the coordinate system of the multi-degree-of-freedom robotic arm. The multi-degree-of-freedom robotic arm aligns the tightening mechanism with the bolt holes and fits them through pose transformation.

[0023] Step 2: Control the axial pushing mechanism to insert into the nut storage compartment. The axial pushing mechanism pushes the nut fixing component and the bolt positioning connector towards the bolt hole. When the bolt to be installed is inserted into the bolt hole, until the infrared sensor inside the tightening mechanism recognizes the pre-installed nut on the bolt to be installed, the electric clamping blade automatically extends and clamps the pre-installed nut. Under the action of the rotary drive device, the clamping and positioning device of the tightening mechanism starts to rotate. The pressure sensor inside the tightening mechanism provides real-time feedback on the force of the pre-installed nut to the background management system. When the force of the pre-installed nut reaches the threshold, the tightening mechanism automatically stops tightening, the electric clamping blade retracts, and the pre-installed nut installation is completed.

[0024] Step 3: The vision component scans and identifies the surrounding working conditions and transmits them to the back-end management system for analysis. It determines the bolt hole position information at the other end of the bolt to be installed. The multi-degree-of-freedom robotic arm moves to the designated position through pose transformation. The axial pushing mechanism continues to push the nut fixing component. The position of the nut fixing component is finely adjusted so that the nut on it fits into the bolt. The tightening process of Step 2 is repeated.

[0025] Step 4: After completing the assembly of one bolt, the axial pushing mechanism drives the nut fixing component and the bolt positioning connector to reset. The axial pushing mechanism then exits the nut storage compartment. The rotary storage unit rotates a certain angle through the rotary device until the next nut storage compartment is axially aligned with the axial pushing mechanism. Repeat steps one to three until the bolt assembly of one ring of segments is completed.

[0026] Step 5: After the bolts and nuts to be installed in the built-in rotary storage mechanism are assembled, the tunnel segment bolt automatic assembly system, under the position change of the multi-degree-of-freedom robotic arm, adjusts to the angle suitable for the construction personnel to add the bolts and nuts to be installed. The construction personnel open the end cover at the front end of the rotary storage unit to add the bolts and nuts.

[0027] Compared with existing technologies, the device of this invention is designed to store a sufficient number of bolts and nuts. Whether for circumferential or axial bolt connections, the number of bolts stored by the device can meet the requirements. Each bolt has a pre-tightened nut at its rear end, so only two pushes are needed to complete the assembly of a bolt, saving time and improving bolt assembly efficiency. Furthermore, the storage compartment in the rotary storage unit is designed as a through hole, which not only simplifies the structure and facilitates manufacturing, but also makes it suitable for bolts of different diameters and shapes, thus increasing the applicability of the device. When tightening the nut, since both overtightening and loosening can affect the tunnel segments, a pressure sensor is added to the device to provide real-time feedback on the force on the nut to the back-end management system. When the force on the nut reaches a certain threshold, tightening automatically stops. Considering the limited space for tunnel segment installation and the complexity of the bolt assembly process, the automatic bolt assembly system for tunnel segments of this invention has a compact structure and flexible operation, and can efficiently and stably complete the bolt assembly work. This invention can independently complete the assembly process, working simultaneously with the segment assembly machine without affecting its operation, fundamentally improving bolt assembly efficiency. The tightening device's front end is designed according to the segment's curvature, preventing collisions between the tightening mechanism and the segment during bolt assembly, thus improving safety. The hydraulic drive method of this invention is selected based on the segment assembly machine's drive mode, facilitating control system management and maintenance. This invention can be applied to segment assembly machines with a tunnel boring machine diameter of 6.4m or more. It connects to the segment assembly machine's chuck via a snap-fit ​​device, making assembly and disassembly convenient and highly versatile. It can also move with the chuck to the vicinity of the bolt holes, reducing movement time and improving efficiency. This invention incorporates electronic components such as infrared sensors, pressure sensors, and displacement sensors, enabling functions such as identifying and locating bolt holes. It can efficiently and safely replace construction personnel in bolt assembly work, effectively ensuring their safety and driving the segment assembly machinery towards full automation. Attached Figure Description

[0028] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 for Figure 1 Enlarged view of the slewing device and the axial pushing mechanism;

[0031] Figure 3 for Figure 1 A partial cross-sectional view of a rotary storage unit;

[0032] Figure 4 for Figure 1 A schematic diagram of the tightening mechanism and the rotary storage unit;

[0033] Figure 5 for Figure 1 Enlarged view of the tightening mechanism. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] An automated assembly system for tunnel segment bolts, such as Figures 1-5 As shown, the device includes a multi-degree-of-freedom robotic arm 2. The execution end of the multi-degree-of-freedom robotic arm 2 is connected to a rotary storage unit. The rotary storage unit stores bolts and nuts to be installed. By rotating, each group of bolts and nuts is aligned with the axial direction of the execution end. The bolts and nuts are delivered by pushing the execution end.

[0036] Specifically, the rotary storage unit includes a storage mechanism housing 7 and a main control compartment 8-3 located inside the housing 7. A rotating device 10 is installed inside the housing 7. The front of the rotating device 10 is connected to a bolt storage device 8, and the rear is connected to a nut storage device 9. The rotating device 10 synchronously drives the bolt storage device 8 and the nut storage device 9 to rotate, causing the corresponding bolts and nuts to enter the installation position. The bolt storage device 8 has several bolt storage compartments 8-1 arranged in a ring, each storing one bolt with a pre-installed nut. The nut storage device 9 has several nut storage compartments 9-1 arranged in a ring, each corresponding to one of the bolt storage compartments 8-1. Each nut storage compartment 9-1 stores one nut, used in conjunction with the bolt stored in the bolt storage compartment 8-1.

[0037] The front end of the storage mechanism housing 7 is provided with a tightening mechanism 11 and a vision device 12 that cooperate with the bolt storage bin 8-1. The vision device 12 is used to detect the position of the bolt hole and locate the position of the multi-degree-of-freedom robotic arm 2. When the actuator pushes the bolt or nut to the tightening mechanism 11, the tightening mechanism 11 clamps the corresponding nut to tighten it.

[0038] The multi-degree-of-freedom robotic arm 2 is equipped with an axial pushing mechanism that extends into the nut storage compartment 9-1. This mechanism pushes bolts and nuts into their corresponding bolt holes and to the corresponding positions on the tightening mechanism 11, thus assembling the nuts and bolts. The multi-degree-of-freedom robotic arm 2, the axial pushing mechanism, the rotary device 10, and the vision device 12 are all connected to the control system. All actions of this system are automatically performed through the control system. The vision device 12 includes an industrial camera 12-1, configured to detect the position of the bolt holes. It can scan and identify the surrounding pipe segments and feed the information back to the main control unit for analysis in the background system. This determines the bolt hole position, obtains the pose in the multi-degree-of-freedom robotic arm coordinate system, and uses inverse kinematics to obtain the joint posture information of the multi-degree-of-freedom robotic arm. Based on the position information, trajectory planning and pose transformation are performed.

[0039] Specifically, the nut storage device 9 includes a rotary table connected to the multi-degree-of-freedom robotic arm 2 via a ball joint. A nut storage chamber 9-1 is mounted on the rotary table, and a nut fixing assembly 9-2 is disposed within the nut storage chamber 9-1. The axial pushing mechanism engages with the nut fixing assembly 9-2. The nut fixing assembly 9-2 includes a fixed disc 9-2-1 slidably disposed within the nut storage chamber 9-1. A fixed shaft 9-2-2 is disposed on the inner side of the fixed disc 9-2-1. Nuts to be installed are inserted into the fixed shaft 9-2-2, and the fixed shaft 9-2-2 axially corresponds to the bolts to be installed in the bolt storage chamber 8-1.

[0040] In a preferred embodiment, the outer circumference of the fixed disc 9-2-1 is provided with a rubber air bladder, which slides in contact with the inner wall of the nut storage chamber 9-1 and the inner wall of the bolt storage chamber 8-1. The rubber air bladder around the circumference of the fixed disc serves two purposes: firstly, it prevents the nut fixing assembly 9-2 from sliding up and down arbitrarily during movement within the nut storage chamber 9-1, increasing friction; secondly, it reduces wear on parts. A rubber head is designed at the front end of the fixed shaft 9-2-2 to reduce collisions and wear when the fixed shaft 9-2-2 pushes out the bolt; in the vertical direction, the rubber head also prevents the nut from falling off, thus providing a fixing function.

[0041] In a preferred embodiment, the bolt storage chamber 8-1 is provided with a sliding groove, and a pulley is provided in conjunction with the sliding groove. The pulley is connected to a bolt positioning connector 8-2, and an electric gripper for fixing the bolt to be installed is provided on the bolt positioning connector 8-2. The electric gripper is connected to the control system. The bolt positioning connector 8-2 can be inserted into the sliding groove and is detachable. One side of the bolt positioning connector 8-2 has a pulley that connects to the inner wall of the sliding groove, and the upper part has a gripper. The gripper is connected to the bolt positioning connector 8-2 through a pin. The motor drives the gripper to open and close, so as to fix the bolt to be installed in the bolt storage chamber 8-1 and prevent it from moving.

[0042] In a preferred embodiment, the tightening mechanism 11 includes a clamping and positioning device 11-1 driven by a rotary drive device 11-2. The clamping and positioning device 11-1 includes at least two electrically driven clamping blades 11-1-1 disposed in a groove. An infrared sensor 11-1-2 is disposed on the electrically driven clamping blades 11-1-1. When the infrared sensor 11-1-2 detects the nut, the control system controls the electrically driven clamping blades 11-1-1 to extend radially to clamp the nut, and then controls the rotary drive device 11-2 to rotate. A pressure sensor 11-1-3 connected to the control system is disposed between the front sidewall of the groove and the clamping and positioning device 11-1.

[0043] In a preferred embodiment, the axial pushing mechanism includes a pushing cylinder 3 equipped with a displacement sensor 3-1, a pushing device 4 connected to the piston rod end of the pushing cylinder 3, a protective sleeve 6 provided outside the rodless cavity, and a balancing cylinder 5 ball-jointed between the protective sleeve 6 and the nut storage device 9, thereby achieving flexible adjustment and precise positioning.

[0044] The pushing device 4 includes a connecting platform 4-3 hinged to the piston rod end of the pushing cylinder 3. Several fine-tuning cylinders 4-2 are hinged to the connecting platform 4-3. The piston rod ends of the fine-tuning cylinders 4-2 are hinged to the same pushing platform 4-1. An electromagnet is installed between the pushing platform 4-1 and the nut storage device 9. The pushing cylinder 3, displacement sensor 3-1, fine-tuning cylinders 4-2, and electromagnet are all connected to the control system. The pushing cylinder 3 plays the main pushing role, and the various fine-tuning cylinders 4-2 cooperate with each other. Through extension and retraction adjustment, their relative positional relationship with the nut fixing assembly 9-2 can be changed, thereby achieving fine-tuning of the bolt and nut posture.

[0045] In a preferred embodiment, the rotary device 10 includes a drive unit 10-2 connected to the control system. The drive unit 10-2 meshes with a large gear ring 10-1 via a transmission unit and a drive gear 10-3. The large gear ring 10-1 is slidably disposed within the storage mechanism housing 7. The bolt storage device 8 and the nut storage device 9 are respectively connected to both sides of the large gear ring 10-1. The drive unit 10-2 includes a hydraulic motor, a reducer, etc., disposed between the large gear ring 10-1 and the storage mechanism housing 7. The power output of the hydraulic motor drives the large gear ring 10-1 to rotate 360 ​​degrees, thereby driving the bolt storage device 8 and the nut storage device 9 to rotate within the storage mechanism housing 7.

[0046] In a preferred embodiment, the multi-degree-of-freedom robotic arm 2 includes a base 2-1. The base 2-1 is connected to a first main arm link 2-4 via a rotary mechanism 2-2. The first main arm link 2-4 is connected to the execution end via a second main arm link 2-6. Servo motors connected to the control system are provided between the rotary mechanism 2-2 and the first main arm link 2-4, between the first main arm link 2-4 and the second main arm link 2-6, and between the second main arm link 2-6 and the execution end.

[0047] Specifically, the servo motors include a first servo motor 2-3 disposed between the rotary mechanism 2-2 and the first upper arm connecting rod 2-4, a first upper arm servo motor 2-5 disposed between the first upper arm connecting rod 2-4 and the second upper arm connecting rod 2-6, and a second upper arm servo motor 2-7 disposed between the second upper arm connecting rod 2-6 and the actuator. Preferably, the actuator is hinged to the second upper arm connecting rod 2-6 via a wrist connecting rod 2-8, the second upper arm servo motor 2-7 is disposed between the wrist connecting rod 2-8 and the second upper arm connecting rod 2-6, and the protective sleeve 6 is disposed on the wrist connecting rod 2-8. The first upper arm connecting rod 2-4 can rotate circumferentially relative to the base 2-1 via the rotary mechanism 2-2, and pitch motion can be achieved between the first upper arm connecting rod 2-4 and the second upper arm connecting rod 2-6, and between the second upper arm connecting rod 2-6 and the wrist connecting rod 2-8.

[0048] An automated assembly method for tunnel segment bolts, employing the aforementioned automated assembly system for tunnel segment bolts, includes the following steps:

[0049] Step 1: The tunnel segment bolt automatic assembly system moves towards the tail of the shield under the action of the multi-degree-of-freedom robotic arm 2. The vision device 12 located on the tightening mechanism 11 scans and identifies the surroundings, and transmits the scan information to the background management system through the control system for analysis. The system determines the position of the bolt holes of the tunnel segment and obtains the pose of the bolt holes in the coordinate system of the multi-degree-of-freedom robotic arm 2. The multi-degree-of-freedom robotic arm 2 aligns the tightening mechanism 11 with the bolt holes and fits them through pose transformation.

[0050] Specifically, under the action of the vision device 12, a coarse adjustment is first performed. The control system first adjusts the position and posture of the multi-degree-of-freedom robotic arm 2 so that the tightening mechanism 11 is initially aligned with the bolt holes of the bolt assembly to be installed. Then, a medium adjustment is performed. The control system controls the extension and retraction of the balance cylinder 5 so that the tightening mechanism 11 is further aligned with the bolt holes of the bolt assembly to be installed. Finally, a fine adjustment is performed. The control system controls the extension and retraction of the push cylinder 3 so that the tightening mechanism 11 is precisely aligned with the bolt holes of the bolt assembly to be installed.

[0051] Step Two: Control the axial pushing mechanism to insert into the nut storage compartment 9-1. The axial pushing mechanism pushes the nut fixing assembly 9-2 and the bolt positioning connector 8-2 towards the bolt hole. After the bolt to be installed is inserted into the bolt hole, until the infrared sensor 11-1-2 inside the tightening mechanism 11 detects the pre-installed nut on the bolt, the electric clamping blade 11-1-1 automatically extends and clamps the pre-installed nut. Under the action of the rotary drive device 11-2, the clamping and positioning device 11-1 of the tightening mechanism 11 begins to rotate. The pressure sensor 11-1-3 inside the tightening mechanism 11 provides real-time feedback on the force on the pre-installed nut to the background management system. When the force on the pre-installed nut reaches the threshold, the tightening mechanism 11 automatically stops tightening, the electric clamping blade 11-1-1 retracts, and the pre-installed nut installation is completed.

[0052] Specifically, during the process of pushing the hydraulic cylinder 3 into the nut storage compartment 9-1 and pushing the nut fixing assembly 9-2, the relative positional relationship between the two is adjusted by the fine-tuning hydraulic cylinder 4-2 to achieve precise pushing of the bolt and nut.

[0053] Step 3: The vision component scans and identifies the surrounding working conditions and transmits them to the background management system for analysis. It determines the bolt hole position information at the other end of the bolt to be installed. The multi-degree-of-freedom robotic arm 2 moves to the designated position through pose transformation. The axial pushing mechanism continues to push the nut fixing component 9-2. The position of the nut fixing component 9-2 is finely adjusted so that the nut on it fits into the bolt. The tightening process of step 2 is repeated.

[0054] Step 4: After completing the assembly of one bolt, the axial pushing mechanism drives the nut fixing assembly 9-2 and the bolt positioning connector 8-2 to reset. The axial pushing mechanism exits the nut storage chamber 9-1, and the rotary storage unit rotates a certain angle through the rotary device 10 until the next nut storage chamber 9-1 is axially opposite to the axial pushing mechanism. Repeat steps one to three until the bolt assembly of one ring of pipe segments is completed.

[0055] Step 5: After the bolts and nuts to be installed in the built-in rotary storage mechanism are assembled, the tunnel segment bolt automatic assembly system, under the position change of the multi-degree-of-freedom robotic arm 2, adjusts to the angle suitable for the construction personnel to add the bolts and nuts to be installed. The construction personnel open the end cover at the front end of the rotary storage unit to add the bolts and nuts.

[0056] All aspects not detailed in this invention are conventional technical means known to those skilled in the art.

[0057] The above content shows and describes the basic principles, main features, and beneficial effects of the present invention. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tunnel segment bolt automatic assembly system comprising a multi-degree-of-freedom robot arm (2), characterized in that: The executing end of the multi-degree-of-freedom robot arm (2) is connected with a rotating wheel type storage unit, the rotating wheel type storage unit comprises a storage mechanism shell (7), a rotating device (10) is arranged in the storage mechanism shell (7), the front side of the rotating device (10) is connected with a bolt storage device (8), the rear side is connected with a nut storage device (9), a plurality of annularly distributed bolt storage bins (8-1) are arranged in the bolt storage device (8), a plurality of annularly distributed nut storage bins (9-1) are arranged in the nut storage device (9), the nut storage bin (9-1) corresponds to the bolt storage bin (8-1) one by one, the front end of the storage mechanism shell (7) is provided with a tightening mechanism (11) matched with the bolt storage bin (8-1) and a visual device (12), the executing end of the multi-degree-of-freedom robot arm (2) is provided with an axial pushing mechanism capable of extending into the nut storage bin (9-1), the multi-degree-of-freedom robot arm (2), the axial pushing mechanism, the rotating device (10) and the visual device (12) are connected with a control system; The nut storage device (9) comprises a rotating disc connected with the multi-degree-of-freedom robot arm (2) through a spherical hinge, the nut storage bin (9-1) is arranged on the rotating disc, and a nut fixing assembly (9-2) is arranged in the nut storage bin (9-1); the axial pushing mechanism is in top contact with the nut fixing assembly (9-2); The tightening mechanism (11) comprises a clamping positioning device (11-1) driven by a rotary driving device (11-2), the clamping positioning device (11-1) comprises at least two electric clamping blades (11-1-1) arranged in a groove, an infrared sensor (11-1-2) is arranged on the electric clamping blade (11-1-1), when the infrared sensor (11-1-2) detects the nut, the control system controls the electric clamping blade (11-1-1) to radially extend to clamp the nut, then the rotary driving device (11-2) is controlled to rotate, and a pressure sensor (11-1-3) connected with the control system is arranged between the front side wall of the groove and the clamping positioning device (11-1); The axial pushing mechanism comprises a pushing oil cylinder (3) provided with a displacement sensor (3-1), the piston rod end of the pushing oil cylinder (3) is connected with a pushing device (4), the outer part of the rodless cavity is provided with a protective sleeve (6), the protective sleeve (6) is connected with the nut storage device (9) through a spherical hinge, a balance oil cylinder (5), the pushing device (4) comprises a connecting platform (4-3) hinged to the piston rod end of the pushing oil cylinder (3), a plurality of fine adjustment oil cylinders (4-2) are hinged to the connecting platform (4-3), the piston rod ends of the fine adjustment oil cylinders (4-2) are hinged to the same pushing platform (4-1), an electromagnet is arranged between the pushing platform (4-1) and the nut storage device (9), and the pushing oil cylinder (3), the displacement sensor (3-1), the fine adjustment oil cylinder (4-2) and the electromagnet are connected with the control system.

2. The tunnel segment bolt auto-assembly system of claim 1, wherein: The nut fixing assembly (9-2) comprises a fixing disc (9-2-1) slidingly arranged in the nut storage bin (9-1), and the inner side of the fixing disc (9-2-1) is provided with a fixing shaft (9-2-2), the nut to be installed is inserted on the fixing shaft (9-2-2), and the fixing shaft (9-2-2) is axially corresponding to the bolt to be installed in the bolt storage bin (8-1).

3. The tunnel segment bolt auto-assembly system of claim 2, wherein: The outer circumferential surface of the fixing disc (9-2-1) is provided with a rubber air bag, and the rubber air bag is in sliding cooperation with the inner walls of the nut storage bin (9-1) and the bolt storage bin (8-1).

4. The tunnel segment bolt auto-assembly system according to any one of claims 1-3, wherein: The bolt storage bin (8-1) is provided with a sliding groove, and a pulley is arranged in cooperation with the sliding groove, the pulley is connected with a bolt positioning plug-in part (8-2), the bolt positioning plug-in part (8-2) is provided with an electric gripper for fixing the bolt to be installed, and the electric gripper is connected with the control system.

5. The tunnel segment bolt auto-assembly system of claim 4, wherein: The rotary device (10) comprises a driving unit (10-2) connected with the control system, the driving unit (10-2) is engaged with a large gear ring (10-1) through a transmission unit and a driving gear (10-3), the large gear ring (10-1) is slidingly arranged in the storage mechanism shell (7), and the bolt storage device (8) and the nut storage device (9) are connected on the two sides of the large gear ring (10-1) respectively.

6. The tunnel segment bolt auto-assembly system according to any one of claims 1-3, 5, wherein: The multi-degree-of-freedom mechanical arm (2) comprises a base (2-1), the base (2-1) is connected with a first large arm connecting rod (2-4) through a rotary mechanism (2-2), the first large arm connecting rod (2-4) is connected with the execution end through a second large arm connecting rod (2-6), and the rotary mechanism (2-2), the first large arm connecting rod (2-4), the first large arm connecting rod (2-4) and the second large arm connecting rod (2-6), and the second large arm connecting rod (2-6) and the execution end are all provided with servo motors connected with the control system.

7. A method for automated assembly of tunnel segment bolts, characterized by: The automatic assembly method comprises the following steps: Step one: the tunnel segment bolt automatic assembly system moves to the shield tail direction under the action of the multi-degree-of-freedom mechanical arm (2), the visual device (12) on the tightening mechanism (11) scans and identifies the surrounding, and transmits the scanning information to the background management system through the control system for analysis, determines the position of the bolt hole of the tunnel segment, and obtains the pose of the bolt hole in the coordinate system of the multi-degree-of-freedom mechanical arm (2), and the multi-degree-of-freedom mechanical arm (2) aligns the tightening mechanism (11) with the bolt hole through pose transformation and adhesion. Step two: control the axial pushing mechanism to insert the nut storage bin (9-1), the axial pushing mechanism drives the nut fixing assembly (9-2) and the bolt positioning plug-in part (8-2) to move towards the bolt hole direction, when the to-be-installed bolt passes through the bolt hole, until the infrared sensor (11-1-2) in the tightening mechanism (11) recognizes the pre-installed nut on the to-be-installed bolt, the electric clamping blade (11-1-1) automatically extends and clamps the pre-installed nut, under the action of the rotary driving device (11-2), the clamping positioning device (11-1) of the tightening mechanism (11) starts to rotate, the pressure sensor (11-1-3) in the tightening mechanism (11) feedbacks the stress condition of the pre-installed nut to the background management system in real time, when the stress of the pre-installed nut reaches the threshold value, the tightening mechanism (11) automatically stops tightening, the electric clamping blade (11-1-1) retracts, and the pre-installed nut is installed; Step three: the visual assembly scans and identifies the surrounding work situation and transmits it to the background management system for analysis to determine the bolt hole position information of the other end of the to-be-installed bolt, the multi-degree-of-freedom robot arm (2) moves to the specified position through pose transformation, the axial pushing mechanism continues to push the nut fixing assembly (9-2), and the position of the nut fixing assembly (9-2) is fine-tuned so that the nut on it is fitted into the bolt, and the tightening process of step two is repeated; Step four: after completing the assembly of one bolt, the axial pushing mechanism drives the nut fixing assembly (9-2) and the bolt positioning plug-in part (8-2) to reset, the axial pushing mechanism exits the nut storage bin (9-1), the rotating wheel type storage unit rotates through the rotating device (10) by a certain angle, until the next nut storage bin (9-1) is axially opposite to the axial pushing mechanism; repeat steps one to three until the bolt assembly of one ring segment is completed; Step five: after the to-be-installed bolt and nut in the rotating wheel type storage mechanism are assembled, the tunnel segment bolt automatic assembly system adjusts to an angle suitable for the construction personnel to add the to-be-installed bolt and nut under the position transformation of the multi-degree-of-freedom robot arm (2), the construction personnel opens the end cover at the front end of the rotating wheel type storage unit, and adds the bolt and nut.

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