Shield tunneling machine and tool changing method thereof

Abstract

The invention relates to a shield tunneling machine and a tool changing method thereof, and belongs to the technical field of robots, and when it is monitored that the shield tunneling machine has a tool with over-limit wear, point cloud data of a preset operation space needing to execute tool changing operation path planning is obtained; determining the current position of the tool changing robot, adjusting the operation space to a path planning space between the current position of the tool changing robot and the position of the tool, and setting a current search step length; the current search step length is inversely proportional to the current complexity coefficient; taking the current position of the tool changing robot as a starting point, taking the tool position of the tool to be changed as a terminal point, and calling a preset path planning algorithm to obtain the next position of the tool changing robot based on the current search step length; taking the next position of the tool changing robot as the current position of the tool changing robot, repeatedly obtaining the next position until the next position of the tool changing robot meets the tool changing condition, and generating a feasible path so as to execute tool changing operation on the tool to be changed and realize automatic tool changing.

Description

Technical Field

[0001] This invention relates to a tunnel boring machine and its cutterhead changing method, belonging to the field of robotics technology. Background Technology

[0002] Tunnel boring machine (TBM) construction faces complex and ever-changing geological conditions. During tunneling, tool wear occurs, requiring frequent inspection and replacement. Currently, tool inspection and replacement are still mainly done manually. Pressurized tool replacement requires workers to enter the manhole, apply pressure, and then replace the tool. After replacement, they return to the manhole to gradually depressurize. This process is time-consuming, affecting the health of workers. Furthermore, the heavy weight of the tools and the narrow working space result in low tool replacement efficiency. As the diameter of the TBM increases, the number of tools, operational difficulty, and operational risks all increase accordingly, which does not meet the current requirements for safe and efficient tunnel construction.

[0003] To address the aforementioned issues, Chinese invention patent application CN119036473B discloses a method, device, and related products for changing cutterheads in tunnel boring machines (TBMs) based on a humanoid robot. The method involves: determining the position and first attribute information of the first cutter to be replaced; determining the current position of the humanoid robot; acquiring a first image of the position of the first cutter in the TBM and the ground below it; using the first image to determine a first position and controlling the humanoid robot to move to that position; acquiring second attribute information of the humanoid robot; determining the target posture parameters of the humanoid robot based on the first and second attribute information; and controlling the humanoid robot to perform corresponding posture movements according to the target posture parameters, and controlling the robotic arm to replace the first cutter according to the cutterhead replacement operation steps. However, determining the robot's walking path requires ensuring an open path, which increases the environmental requirements for the cutterhead replacement operation. Since other components exist at the cutterhead replacement location, and some areas are narrow, increasing the search step size of the path planning algorithm can ensure safety and avoid interference between the cutterhead replacement robot and other structures, but it increases path planning time, leading to lower cutterhead replacement efficiency. Therefore, it is difficult to guarantee a balance between cutterhead replacement efficiency and safety.

[0004] In addition, the monitoring of whether the cutters on the cutterhead of the tunnel boring machine need to be replaced involves judging the similarity between each cutter and multiple standard images. This monitoring method is complex and cannot detect the wear of the cutters in a timely manner during the operation of the tunnel boring machine or in other states, thereby reducing the triggering of cutter replacement operations and resulting in low work efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a tunnel boring machine and its cutterhead replacement method, which solves the problem that it is difficult to balance efficiency and safety when using a cutterhead replacement robot for automatic cutterhead replacement in tunnel boring machines.

[0006] To achieve the above objectives, the present invention proposes a cutterhead replacement method for a tunnel boring machine, comprising the following steps:

[0007] 1) When the shield machine detects that the cutter has worn beyond the limit, obtain the point cloud data of the working space where the preset cutter replacement operation path planning needs to be performed, and determine the location of the obstacle and the location of the cutter to be replaced.

[0008] 2) Determine the current position of the tool-changing robot, and based on the current position of the tool-changing robot and the position of the obstacles, adjust the workspace to the path planning space between the current position of the tool-changing robot and the position of the tool, and determine the current complexity coefficient based on the obstacle situation in the current path planning space; set the current search step size based on the current complexity coefficient; the current search step size is inversely proportional to the current complexity coefficient;

[0009] 3) Starting from the current position of the tool changing robot and ending at the position of the tool to be replaced, the next position of the tool changing robot is obtained by calling the preset path planning algorithm based on the current search step size.

[0010] 4) Repeat steps 2) and 3) with the next position of the tool changing robot as the current position of the tool changing robot until the next position of the tool changing robot meets the tool changing conditions, generate a feasible path, so that the tool changing robot can reach the tool position of the tool to be replaced according to the feasible path and perform the tool changing operation.

[0011] Furthermore, the current complexity coefficient is determined by the ratio between the total volume of obstacles in the current path planning space and the volume of the current path planning space.

[0012] Furthermore, the current complexity coefficient is calculated using the following formula:

[0013]

[0014] Where K is the current complexity coefficient; V obs V represents the total volume of obstacles in the current path planning space. spa Plan the spatial volume for the current path.

[0015] Furthermore, based on the current complexity coefficient, the current search step size is calculated using the following formula:

[0016]

[0017] Where λ is the current search step size; K is the current complexity coefficient; S base d is the reference step size for the tool-changing robot. |q-qs| The distance between the current position q of the tool-changing robot and the tool position qs is given.

[0018] Furthermore, the tool-changing condition is that the distance between the next position of the tool-changing robot and the tool position is less than a preset distance threshold for performing the tool-changing operation.

[0019] Furthermore, wear monitoring of the cutters in the tunnel boring machine is performed through the following steps:

[0020] Acquire point cloud data of the cutting tools during the tunnel boring machine's excavation process;

[0021] The wear depth of the tool is calculated based on the point cloud data of the tool; when the wear depth of the tool is greater than the preset tool wear depth threshold, the tool is identified as a tool with excessive wear.

[0022] Furthermore, when the cutting tool is a hob, the symmetry state of the hob is analyzed when calculating the wear depth of the hob;

[0023] When the tool wears symmetrically, the wear depth of the tool is calculated using the following formula:

[0024]

[0025] Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; right The height difference between the deepest wear point on the right side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section;

[0026] When the tool wears asymmetrically, and the wear on the left side is greater than that on the right side, the wear depth of the tool is calculated using the following formula:

[0027]

[0028] Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob's cutting edge cross-section and the highest point of the cutting edge on the hob's centerline; right The height difference between the deepest wear point on the right side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section;

[0029] When the tool wears asymmetrically, and the wear on the left side is less than that on the right side, the wear depth of the tool is calculated using the following formula:

[0030]

[0031] Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; right It is the height difference between the deepest wear on the right side of the hob's cutting edge section and the highest point of the cutting edge on the hob's centerline.

[0032] On the other hand, the present invention also proposes a tunnel boring machine, including a cutter-changing robot and a first device for acquiring point cloud data of a pre-set workspace for which a cutter-changing operation path needs to be planned; the cutter-changing robot is used to execute the cutter-changing method of the above-mentioned tunnel boring machine with automatic cutter changing, so that the tunnel boring machine can perform cutter-changing operations through the cutter-changing robot.

[0033] Furthermore, it includes a second device for acquiring point cloud data of the cutting tools during the tunnel boring machine's excavation process.

[0034] The beneficial effects of this invention are as follows: When a cutter on a tunnel boring machine is detected to have excessive wear, point cloud data of the working space for a pre-defined path planning for a cutter replacement operation is obtained, and the positions of obstacles and the cutter to be replaced are determined; the current position of the cutter replacement robot is determined, and based on the current position of the cutter replacement robot and the obstacle positions, the working space is adjusted to the path planning space between the current position of the cutter replacement robot and the cutter position, and the current complexity coefficient is determined based on the obstacle situation in the current path planning space; based on the current complexity coefficient, the current search step size is set; the current search step size is inversely proportional to the current complexity coefficient; taking the current position of the cutter replacement robot as the starting point and the position of the cutter to be replaced as the ending point, based on the current search step size, a pre-defined path planning algorithm is called to obtain the next position of the cutter replacement robot; the next position of the cutter replacement robot is used as the current position of the cutter replacement robot and the operation is repeated: determining the current position of the cutter replacement robot, and based on the current position of the cutter replacement robot and the obstacle positions, the working space is adjusted to the path planning space between the current position of the cutter replacement robot and the cutter position, and based on the current complexity coefficient, the current complexity coefficient is determined; based on the current complexity coefficient, the current search step size is set; the current search step size is inversely proportional to the current complexity coefficient; taking the current position of the cutter replacement robot as the starting point and the position of the cutter to be replaced as the ending point, a pre-defined path planning algorithm is called to obtain the next position of the cutter replacement robot; the next position of the cutter replacement robot is used as the current position of the cutter replacement robot and the operation is repeated: determining the current position of the cutter replacement robot, and based on the current position of the cutter replacement robot and the obstacle positions, the working space is adjusted to the path planning space between the current position of the cutter replacement robot and the cutter position, and based on the current complexity coefficient, the current complexity coefficient is determined; based on the current complexity coefficient, the current search step The current complexity coefficient is determined by the obstacle situation in the path planning space. Based on the current complexity coefficient, the current search step size is set. The current search step size is inversely proportional to the current complexity coefficient. Starting from the current position of the tool-changing robot and ending at the position of the tool to be replaced, a preset path planning algorithm is called based on the current search step size to obtain the next position of the tool-changing robot. This process continues until the next position of the tool-changing robot meets the tool-changing conditions, generating a feasible path. The tool-changing robot then reaches the position of the tool to be replaced according to the feasible path and performs the tool-changing operation. This achieves feasible path planning for the tool-changing robot based on the characteristics of the tunnel boring machine's excavation environment, enabling the tool-changing robot to reach the tool position and perform the tool-changing operation in various complex operating environments. This not only enables automatic tool-changing operations on the tunnel boring machine but also, by analyzing the current complexity coefficient using obstacle situations, further achieves path planning that adjusts the search step size according to the environmental complexity. This balances efficiency and safety in path planning, allowing the tool-changing robot to move stably and safely to the tool position. Attached Figure Description

[0035] Figure 1This is an example diagram of the path planning process of the cutter-changing robot in the cutter-changing method of a tunnel boring machine proposed in this invention;

[0036] Figure 2(a) is a schematic diagram of the symmetrical wear state of the cutter blade cross section in a practical application scenario of the cutter replacement method for a tunnel boring machine proposed in this invention;

[0037] Figure 2(b) is a schematic diagram of the cutter replacement method for a tunnel boring machine proposed in this invention in a practical application scenario, where the cutter blade cross-section is symmetrical and the wear on the left side is greater than the wear on the right side.

[0038] Figure 3 This is a schematic diagram of the structure of a cutter-changing robot for a tunnel boring machine in a practical application scenario, as proposed in this invention.

[0039] Figure 4 This is a schematic diagram showing the installation position of the visual monitoring device on the shield frame of a tunnel boring machine in a practical application scenario, as proposed in this invention.

[0040] Figure 5 This is a flowchart of the robot cutter replacement operation in a practical application scenario of the cutter replacement method for a tunnel boring machine proposed in this invention.

[0041] Figure 6 This is a block diagram of a cutter-changing robot system for a tunnel boring machine in a practical application scenario, as proposed in this invention.

[0042] Figure label:

[0043] 1-Slide table; 2-Rotating component; 3-First-stage swing component; 4-Second-stage swing component; 5-Third-stage swing component; 6-End actuator; 7-Cutting tool; 8-Ground rail; 9-Visual monitoring device; 10-Shield machine frame; 11-Door;

[0044] 601 - Visual navigation device; 602 - Tool shaft clamping jaws; 603 - Clamping jaws. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0046] The inventive concept of this invention is as follows: In order to replace worn-out cutting tools in tunnel boring machines in a timely manner, the path planning of the cutting tool changing robot is carried out in combination with the obstacle situation in the path planning space. This enables the cutting tool changing robot to smoothly reach the position of the worn-out cutting tool and perform the cutting tool changing operation in the complex and ever-changing tunnel environment, effectively avoiding the problems of low efficiency and high danger caused by manual cutting tool changing operation.

[0047] Specific implementation method 1 for cutterhead replacement of tunnel boring machines:

[0048] Because the cutterhead changing robot operates in a narrow and complex environment with various obstacles, when there are cutters in the tunnel boring machine cutterhead that have exceeded their wear limits, these worn cutters are the ones that need to be replaced. To prevent the cutterhead changing robot from colliding with other structures during its movement, this invention proposes a cutterhead changing method for tunnel boring machines, such as... Figure 1 The diagram shown is an example of the path planning process for the cutter-changing robot in a cutter-changing method for a tunnel boring machine proposed in this invention. It includes steps S11-S14, specifically:

[0049] The system acquires a preset working space image for the tool-changing operation path planning in real time, and processes the image through noise reduction and downsampling. In practical applications, the working space image is acquired using a visual navigation device mounted on the end effector of the tool-changing robot. Based on the processed working space image, point cloud data of the working space is generated. Step S11 is executed to acquire the preset point cloud data of the working space for the tool-changing operation path planning, and to determine the positions of obstacles and the tool to be replaced. It should be noted that the preset working space for the tool-changing operation path planning refers to the spatial range within which the tool-changing robot can stably and safely move to the position of the tool to be replaced through path planning. This preset working space can be set according to the structural characteristics of the tunnel boring machine, the structural characteristics of the tool-changing robot, or the spatial requirements of the tunnel project. The obstacles include one, two, or more. Simultaneously, the acquired point cloud data is also aligned and registered, features are extracted, and then a plane is reconstructed to obtain obstacle pose information more accurately and quickly, and to plan feasible routes.

[0050] When the tool-changing robot performs path planning, the space available for the planned path changes constantly at different positions, and the situation of obstacles within that space also changes continuously. Therefore, in step S12, the current position of the tool-changing robot is determined, and based on the current position of the tool-changing robot and the positions of the obstacles, the working space is adjusted to the path planning space between the current position of the tool-changing robot and the position of the tool. The current complexity coefficient is determined based on the obstacle situation in the current path planning space. Based on the current complexity coefficient, the current search step size is set. The current search step size is inversely proportional to the current complexity coefficient. Here, the obstacle situation includes, but is not limited to, information such as the number, size, volume, and distribution of obstacles used to determine the state of obstacles in the current path planning space. This enables dynamic adjustment of the current path planning space and the current complexity coefficient based on the current position of the tool-changing robot. Simultaneously, the current complexity coefficient is set in conjunction with the obstacle situation in the current path planning space. By constraining the search step size of the path planning through different current complexity systems, a deeper understanding of the obstacle situation in the current path planning space is achieved, and constraints are placed on the search step size for the next position, enabling the tool-changing robot to move safely and stably to its next position.

[0051] Step S13: Taking the current position of the tool-changing robot as the starting point and the position of the tool to be replaced as the ending point, based on the current search step size, a preset path planning algorithm is invoked to obtain the next position of the tool-changing robot. The preset path planning algorithm includes, but is not limited to, a path planning algorithm based on fast expanding random numbers. Here, the preset path planning algorithm can be selected according to the needs of different engineering practices. In a preferred embodiment of the present invention, the preferred preset path planning method is a path planning algorithm based on fast expanding random numbers. The path planning algorithm specifically involves: establishing a mathematical model between the tunnel boring machine cutterhead, the tool to be replaced, and the tool-changing robot; calculating the pose information of each obstacle and the tool to be replaced based on the digital model; planning the obstacle avoidance path of the tool-changing robot; and confirming the starting point q of the tool-changing robot according to the coordinate system of the mathematical model. s and the target point q of the tool to be replaced tar Information, generate random sampling points q rand Search for q on the search tree rand The nearest node q near q is obtained by using this step size in the direction of the straight line. new This node is then used as a tree node to continue the search. During the search, if no collision occurs, q is... new Add the node to the search tree and record it as the parent node. If a collision occurs, randomly select a new node until the search point matches the target point q. tar If the value falls below a set threshold, the search stops and a feasible path is generated. Meanwhile, during the q... new During the search, the current search step size is introduced to adjust q.new Find the range to constrain.

[0052] Step S14: Repeat steps S12 and S3, taking the next position of the tool-changing robot as the current position of the tool-changing robot, until the next position of the tool-changing robot meets the tool-changing condition, and generate a feasible path; here, the tool-changing condition refers to the condition that ensures the tool-changing robot can perform the tool-changing operation and is used to stop the loop, which includes, but is not limited to, distance conditions, time conditions, etc. In a preferred embodiment of the present invention, the preferred tool-changing condition is that the distance between the next position of the tool-changing robot and the tool position is less than a preset distance threshold for performing the tool-changing operation.

[0053] For example, when the tool changing condition is a distance condition, a preset distance threshold of 2m is used to perform the tool changing operation. When the distance d between the next position of the tool changing robot and the tool position is less than 2m, the search for the next position of the tool changing robot stops, and a feasible path is generated. When the tool changing condition is a time condition, a preset time threshold of 10min is used. The time t for cyclically obtaining the next position of the tool changing robot is recorded. When the time t for obtaining the next position reaches 10min, the search for the next position of the tool changing robot stops, and a feasible path is generated. Of course, the time threshold must ensure that the tool changing robot can move from the initial position to the tool position. The initial position refers to the first determined current position of the tool changing robot.

[0054] Through steps S11-S14, during the replacement of the cutter on the tunnel boring machine, the path planning space and complexity coefficient are dynamically adjusted based on the different position information of the cutter-changing robot. The complexity coefficient is then used to constrain the search step size, so that obstacle situations are incorporated into the solution path planning process. This avoids the phenomenon of collision between the cutter-changing robot and obstacles when running along the feasible path, ensuring that the cutter-changing robot reaches the position of the cutter to be replaced safely, stably, and quickly.

[0055] For example, a pre-defined image of the workspace M for which tool change operation path planning needs to be performed is acquired, and noise reduction and downsampling are performed on the workspace M image to improve its clarity; point cloud data is generated based on the processed workspace M image, and the tool position A of the tool to be replaced and the positions of n obstacles (obstacle 1 position B1, obstacle 2 position B2, ..., obstacle n position B1) are determined from the point cloud data. n (where n is an integer greater than 1).

[0056] Determine the current position C1 of the tool-changing robot in the point cloud data of the workspace M; based on the current position C1, obstacle 1 position B1, obstacle 2 position B2, ..., obstacle n position B... n, adjust the operation space M to the path planning space m1 between the current position C1 and the tool position A; analyze the obstacle situation in the path planning space m1, preferably including obstacles 1 - obstacle i (where i is an integer greater than or equal to 1 and i < n) in the path planning space m1, and based on the position B1 of obstacle 1 - the position B of obstacle i i Determine the current complexity coefficient K1, and at the same time set the current search step λ1; starting from the current position C1 and ending at the tool position A, based on the current search step λ1, call the path planning algorithm based on fast expanding random numbers to obtain the next position C2 of the tool changing robot; preferably set the distance threshold 2m for performing the tool changing operation, calculate that the distance d1 between the next position C2 of the tool changing robot and the tool position A is greater than 2m, determine the current position as C2, and continue to search for the next position.

[0057] Similarly, according to the current position C2, the position B1 of obstacle 1, the position B2 of obstacle 2,..., the position B of obstacle n n , adjust the operation space M to the path planning space m2 between the current position C2 and the tool position A; analyze the obstacle situation in the path planning space m2, preferably including obstacles 1 - obstacle j (where j is an integer greater than or equal to 1 and j < n) in the path planning space m2, and based on the position B1 of obstacle 1 - the position B of obstacle j j Determine the current complexity coefficient K2, and at the same time set the current search step λ2; starting from the current position C2 and ending at the tool position A, based on the current search step λ2, call the path planning algorithm based on fast expanding random numbers to obtain the next position C3 of the tool changing robot; calculate that the distance d2 between the next position C3 of the tool changing robot and the tool position A is greater than 2m, determine the current position as C3, and continue to search for the next position,... Preferably, after obtaining the next position Cl of the tool changing robot, preferably set the distance threshold 2m for performing the tool changing operation, calculate that the distance dl between the next position Cl of the tool changing robot and the tool position A is less than 2m. At this time, generate a feasible path, that is, {C2, C3,..., Cl}.

[0058] The specific implementation method 2 of the tool changing method for the shield machine:

[0059] Continuing with the above embodiments of the present invention, in step S12, the current complexity coefficient is determined by the ratio between the total volume of obstacles in the current path planning space and the volume of the current path planning space. Here, the ratio between the total volume of obstacles in the current path planning space and the volume of the current path planning space can also be set with a ratio parameter. This ratio parameter can be adjusted according to the needs of different engineering practices. For example, the ratio parameter can be set to 0.1, in which case the current complexity coefficient is 0.1 * (the ratio between the total volume of obstacles in the current path planning space and the volume of the current path planning space). In a preferred embodiment of the present invention, the ratio parameter is preferably 1. In this case, the current complexity coefficient is calculated using the following formula:

[0060]

[0061] Where K is the current complexity coefficient; V obs V represents the total volume of obstacles in the current path planning space. spa Plan the spatial volume for the current path.

[0062] For example, when the next position C2 of the tool-changing robot is obtained in the above embodiment, the current position C1 of the tool-changing robot is determined in the point cloud data of the workspace M; based on the current position C1 and the positions of n obstacles, the workspace M is adjusted to the path planning space m1; the obstacle situation in the path planning space m1 is analyzed, and it is preferred that the path planning space m1 includes obstacles 1 to obstacle i, and the volume of the path planning space m1 is calculated as V. spa1 The total volume of obstacle 1 to obstacle i is V. obs1 ; The current complexity coefficient K1 = V is obtained. obs1 / V spa1 Therefore, based on the current complexity coefficient K1, we can continue searching for the next position.

[0063] Specific implementation method 3 for cutterhead replacement of tunnel boring machines:

[0064] In the actual search process, when the ratio parameter of the current complexity coefficient is 1, the closer the complexity coefficient is to 1, the more complex the space is. Combined with the actual tool changing operation process of the tool changing robot, the complexity is lowest when it exits the cabin. As the end effector of the tool changing robot gets closer and closer to the tool position, the number of obstacles increases. Therefore, a gradient reduction compensation search strategy is adopted to set the corresponding step size according to the gradient of the complexity coefficient. As the complexity of the current path planning space increases, the current search step size is reduced.

[0065] Specifically, the current search step size is calculated using the following formula:

[0066]

[0067] Where λ is the current search step size; K is the current complexity coefficient; S base d is the reference step size for the tool-changing robot. |q-qs| The distance between the current position q of the tool-changing robot and the tool position qs is given.

[0068] In summary, a complexity coefficient that incorporates obstacle situations is introduced into the path planning process of the tool-changing robot, and the complexity coefficient is used to constrain the path search step size to ensure that the generated feasible path enables the tool-changing robot to reach the tool position safely and stably.

[0069] Specific implementation method 4 for cutterhead replacement of tunnel boring machines:

[0070] The present invention proposes a method for changing the cutterhead of a tunnel boring machine, comprising the following steps:

[0071] 1) When a cutter with excessive wear is detected on the tunnel boring machine (TBM), point cloud data of the pre-defined workspace for the planned cutter replacement operation path is acquired, and the positions of obstacles and the cutter to be replaced are determined. Here, the cutter with excessive wear is the cutter to be replaced. In practical applications, the determination of whether a cutter has excessive wear can be made by acquiring real-time images or point cloud data of the cutter. The pre-defined workspace for the planned cutter replacement operation path refers to the spatial range within which the cutter replacement robot can move stably and safely to the position of the cutter to be replaced through path planning. This pre-defined workspace can be set according to the structural characteristics of the TBM, the structural characteristics of the cutter replacement robot, or the spatial requirements of the tunnel project. The obstacles include one, two, or more. Simultaneously, the acquired point cloud data is aligned and registered, features are extracted, and then a plane is reconstructed to obtain obstacle pose information more accurately and quickly, and to plan feasible routes.

[0072] 2) Determine the current position of the tool-changing robot, and based on the current position of the tool-changing robot and the position of obstacles, adjust the workspace to the path planning space between the current position of the tool-changing robot and the position of the tool. Determine the current complexity coefficient based on the obstacle situation in the current path planning space. Set the current search step size based on the current complexity coefficient. The current search step size is inversely proportional to the current complexity coefficient. Here, the obstacle situation includes, but is not limited to, information such as the number, size, volume, and distribution of obstacles used to determine the obstacle status in the current path planning space. This enables dynamic adjustment of the current path planning space and the current complexity coefficient based on the current position of the tool-changing robot. At the same time, the current complexity coefficient is set in conjunction with the obstacle situation in the current path planning space. By constraining the search step size of the path planning through different current complexity systems, a deep understanding of the obstacle situation in the current path planning space is achieved, and constraints are placed on the search step size for the next position, enabling the tool-changing robot to move safely and stably to its next position.

[0073] Simultaneously, the current complexity coefficient is determined by the ratio between the total volume of obstacles in the current path planning space and the volume of the current path planning space. This ratio can also be set as a ratio parameter, which can be adjusted according to the needs of different engineering practices. For example, the ratio parameter can be set to 0.1, in which case the current complexity coefficient is 0.1 * (the ratio between the total volume of obstacles in the current path planning space and the volume of the current path planning space). In a preferred embodiment of the invention, the ratio parameter is preferably 1, in which case the current complexity coefficient is calculated using the following formula:

[0074]

[0075] Where K is the current complexity coefficient; V obs V represents the total volume of obstacles in the current path planning space. spa Plan the spatial volume for the current path.

[0076] In the actual search process, when the ratio parameter of the current complexity coefficient is 1, the closer the complexity coefficient is to 1, the more complex the space is. Combined with the actual tool changing operation process of the tool changing robot, the complexity is lowest when it exits the cabin. As the end effector of the tool changing robot gets closer and closer to the tool position, the number of obstacles increases. Therefore, a gradient reduction compensation search strategy is adopted to set the corresponding step size according to the gradient of the complexity coefficient. As the complexity of the current path planning space increases, the current search step size is reduced.

[0077] Specifically, the current search step size is calculated using the following formula:

[0078]

[0079] Where λ is the current search step size; K is the current complexity coefficient; S base d is the reference step size for the tool-changing robot. |q-qs| The distance between the current position q of the tool-changing robot and the tool position qs is given.

[0080] 3) Starting from the current position of the tool-changing robot and ending at the position of the tool to be replaced, the next position of the tool-changing robot is obtained by calling a preset path planning algorithm based on the current search step size. The preset path planning algorithm includes, but is not limited to, a path planning algorithm based on fast expanding random numbers. Here, the preset path planning algorithm is selected according to the needs of different engineering practices. In the preferred embodiment of the present invention, the preset path planning method is preferably a path planning algorithm based on fast expanding random numbers.

[0081] 4) Repeat steps 2) and 3) with the next position of the tool-changing robot as the current position of the tool-changing robot until the next position of the tool-changing robot meets the tool-changing condition, and generate a feasible path so that the tool-changing robot can reach the tool position of the tool to be replaced according to the feasible path and perform the tool-changing operation. Here, the tool-changing condition refers to the condition that ensures the tool-changing robot can perform the tool-changing operation and is used to stop the loop. It includes, but is not limited to, distance conditions, time conditions, etc. In the preferred embodiment of the present invention, the preferred tool-changing condition is that the distance between the next position of the tool-changing robot and the tool position is less than a preset distance threshold for performing the tool-changing operation.

[0082] In a preferred embodiment of the present invention, in response to the detection of a cutter in the tunnel boring machine that has exceeded its wear limit and needs to be replaced, a preset working space M image of the required cutter replacement operation path is acquired, and the working space M image is processed by noise reduction, downsampling, and other operations to improve the clarity of the working space M image; point cloud data is generated based on the processed working space M image, and the cutter position A of the cutter to be replaced and the n obstacle positions (obstacle 1 position B1, obstacle 2 position B2, ..., obstacle n position B1) are determined from the point cloud data. n (where n is an integer greater than 1).

[0083] Determine the current position C1 of the tool-changing robot in the point cloud data of the workspace M; based on the current position C1, obstacle 1 position B1, obstacle 2 position B2, ..., obstacle n position B... n, adjust the operation space M to the path planning space m1 between the current position C1 and the tool position A; analyze the obstacle situation in the path planning space m1, preferably including obstacles 1 - obstacle i (where i is an integer greater than or equal to 1 and i < n) in the path planning space m1, and calculate the volume of the path planning space m1 as V spa1 , the total volume of obstacles 1 - obstacle i is V obs1 ; obtain the current complexity coefficient K1 = V obs1 / V spa1 , according to K1, call the corresponding calculation formula of the current search step length to obtain the current search step length λ1; take the current position C1 as the starting point and the tool position A as the ending point, based on the current search step length λ1, call the path planning algorithm based on fast expanding random numbers to obtain the next position C2 of the tool changing robot; preferably set the distance threshold 2m for performing the tool change operation, calculate that the distance d1 between the next position C2 of the tool changing robot and the tool position A is greater than 2m, determine the current position as C2, and continue to search for the next position.

[0084] Similarly, according to the current position C2, the position B1 of obstacle 1, the position B2 of obstacle 2,..., the position B of obstacle n n ,..., preferably after obtaining the next position Cl of the tool changing robot, preferably set the distance threshold 2m for performing the tool change operation, calculate that the distance d2 between the next position Cl of the tool changing robot and the tool position A is less than 2m. At this time, generate a feasible path, that is, {C2, C3,..., Cl}, and the tool changing robot reaches the tool position A according to {C2, C3,..., Cl} to perform the tool change operation on the worn - out tool to be replaced.

[0085] Specific implementation method 5 of the tool change method for the shield machine:

[0086] Then, following the above - mentioned embodiments of the present invention, in step 1), the tool wear in the shield machine is monitored through the following steps:

[0087] Obtain the point cloud data of the tool during the tunneling process of the shield machine; in the actual application scenario, take pictures of the tool images during the tunneling process through the visual monitoring system arranged inside the shield machine, and obtain the corresponding point cloud data according to the tool images.

[0088] At the same time, when obtaining the tool point cloud data, noise, background and other disturbances will interfere with the monitoring. It is necessary to crop the originally obtained point cloud data, remove the background point cloud, obtain the preliminary point cloud, perform straight - through filtering processing on the point cloud in the (x, y, z directions), and perform down - sampling processing using a 2×2×2 voxel grid. Fit a plane to the pre - processed point cloud, set the plane equation to be fitted as Q: Ax + By + Cz + D = 0, complete the solution of the plane equation, and perceive the tool state in real time to improve the accuracy of tool wear monitoring.

[0089] Based on the tool's point cloud data, the tool's wear depth is calculated. When the tool's wear depth exceeds a preset tool wear depth threshold, the tool is identified as a tool whose wear has exceeded the limit and needs to be replaced. Here, based on the tool's point cloud data, an edge detection algorithm is used to extract the tool's edge contour, which is compared with the tool's initial standard contour to calculate the size and amount of wear in the wear area. The wear amount is then used to determine whether the limit has been exceeded. The preset tool wear depth threshold can be obtained by establishing a multi-parameter wear depth relationship, such as tool material parameters, hardness parameters, sliding distance parameters, and correction parameters. The correction parameters include vibration correction parameters and temperature correction parameters.

[0090] In practical applications, the preset tool wear depth threshold can be obtained using the following formula:

[0091]

[0092] Where, ω thd K is the tool wear depth threshold; F is the wear coefficient; s is the propulsion force; H is the sliding distance; C is the tool hardness. i Let be the correction parameter for coefficient i, and m be the number of correction parameters.

[0093] When the correction parameter is a vibration correction parameter, it is calculated using the following formula:

[0094]

[0095] Among them, C vib α is the vibration correction parameter; α is the vibration sensitivity coefficient (preferably 0.1); a is the vibration acceleration; a0 is the reference vibration threshold.

[0096] When the correction parameter is a temperature correction parameter, it is calculated using the following formula:

[0097] C tem =1+β·(TT) ref )

[0098] Among them, C tem β is the temperature correction parameter; β is the temperature sensitivity coefficient (preferably 0.02); T is the tool temperature; T ref This is a reference temperature.

[0099] For example, a visual monitoring system installed inside the tunnel boring machine captures images of each cutter during the tunneling process, and point cloud data is obtained from all the cutter images; based on the point cloud data of each cutter, the wear depth ω of each cutter is calculated; and the wear depth of each cutter is determined, that is, ω is determined. i With ω thd The relationship between their magnitudes, where ωi Let ω be the wear depth of the i-th tool; i >ω thd The tool is identified as a tool whose wear exceeds the limit and needs to be replaced, thereby determining whether the wear of several tools exceeds the limit.

[0100] Of course, tool wear can also be assessed using sensors based on electromagnetic, magnetostrictive, and ultrasonic principles to monitor changes in tool diameter and perform calculations to evaluate tool wear.

[0101] Specific implementation method 6 for the cutterhead replacement method of tunnel boring machines:

[0102] Continuing with the above embodiments of the present invention, taking a hob as an example, since hob wear patterns are diverse in actual engineering, in order to simplify the calculation of hob wear, a method for calculating tool wear is designed based on two cases: symmetrical wear and asymmetrical wear of the hob cutting edge. Specifically, when calculating the wear depth of the tool, the symmetrical wear state of the hob is analyzed.

[0103] When the tool wears symmetrically, the wear depth of the tool is calculated using the following formula:

[0104]

[0105] Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; right It is the height difference between the deepest wear on the right side of the hobbing cutter's cutting edge cross-section and the apex of the cutting edge on the cross-section.

[0106] When the tool wears asymmetrically, and the wear on the left side is greater than that on the right side, the wear depth of the tool is calculated using the following formula:

[0107]

[0108] Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob cutting edge section and the highest point a' on the cutting edge along the hob centerline (as shown in Figure 2(b)); right The height difference between the deepest wear on the right side of the hob cutting edge section and the apex b` (b` in Figure 2(b)) on the cutting edge section;

[0109] When the tool is asymmetrical and the wear on the left side is less than that on the right side, the wear depth of the tool is calculated using the following formula:

[0110]

[0111] Where ω is the wear depth of the tool; Y leftY is the height difference between the deepest wear point on the left side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; right It is the height difference between the deepest wear on the right side of the hob's cutting edge section and the highest point of the cutting edge on the hob's centerline.

[0112] Right now,

[0113] Here, the statement that the wear on the left side is greater than the wear on the right side means that the height difference between the deepest wear on the left side of the hob's cutting edge and the highest point of the cutting edge on the hob's centerline is less than the height difference between the deepest wear on the right side of the hob's cutting edge and the apex of the cutting edge on the cutting edge, i.e., Y left <Y right The statement that the wear on the left side is less than the wear on the right side means that the height difference between the deepest wear on the left side of the hob's cutting edge cross-section and the apex of the cutting edge on the cross-section is greater than the height difference between the deepest wear on the right side of the hob's cutting edge cross-section and the highest point of the cutting edge on the hob's centerline, i.e., Y left >Y right .

[0114] As shown in Figures 2(a) and 2(b), Figure a shows the left hob exhibiting symmetrical wear, with a wear depth of [missing information]. In Figure b, the hob on the right exhibits asymmetrical wear, with the wear on the left side exceeding that on the right. The wear depth of the tool is...

[0115] Specific implementation method 1 for tunnel boring machines:

[0116] On the other hand, the present invention also proposes a tunnel boring machine (TBM), including a cutter-changing robot and a first device for acquiring point cloud data of a pre-set workspace for which cutter-changing operation path planning is required. The cutter-changing robot is used to execute the cutter-changing method of the aforementioned automatically-changing TBM, so that the TBM performs the cutter-changing operation through the cutter-changing robot. In practical applications, the first device is a visual navigation device, which corresponds to a visual navigation apparatus and a visual navigation system. The visual navigation system acquires the corresponding point cloud data by acquiring a pre-set workspace image for which cutter-changing operation path planning is required.

[0117] The tunnel boring machine (TBM) includes a second device for acquiring point cloud data of the cutting tools during the TBM's tunneling process. In practical applications, this second device is a visual monitoring device, which corresponds to a visual construction device and a visual monitoring system. Simultaneously, the visual monitoring system acquires the corresponding point cloud data by obtaining images of the cutting tools during the TBM's tunneling process. Furthermore, after acquiring these images, the visual monitoring system uploads them to a host computer (which contains an image processing control system, i.e.,...). Figure 6In the central control system, the host computer uses an edge detection algorithm to extract the edge contour of the tool, compares it with the initial standard contour of the tool, calculates the size and wear amount of the wear area, and decides whether to perform a tool change operation based on whether the wear amount exceeds the limit.

[0118] To achieve automated cutter changing, the cutter-changing robot's structure mainly consists of two modules: the robot body and the end effector. The robot is housed within the robot compartment and possesses multiple degrees of freedom to meet flexible cutter-changing requirements. The end effector enables cutter gripping and the removal and installation of cutter head bolts. The cutter-changing process is primarily divided into the following steps: the robot is positioned in the upper middle part of the tunnel boring machine's shield; the cutterhead rotates to the preset cutter-changing position; the robot exits the compartment to perform the cutter-changing operation; the excavation compartment monitors the cutter; the robot disassembles the cutter to be replaced; the robot returns with the removed cutter; then it enters the excavation compartment with the new cutter for replacement; after completing the cutter-changing, it returns to the robot compartment, closes the compartment door, and depressurizes. The cutter shaft clamping jaws can employ a symmetrical, openable gripping device to provide gripping safety.

[0119] like Figure 3 and 4 As shown, to achieve tool changing tasks in complex, multi-obstacle environments, the slide 1 can move and extend along the ground track 8; equipped with a rotary component 2, a first-stage swing component 3, a second-stage swing component 4, and a third-stage swing component 5, it allows the subsequent components of each mechanism to rotate or swing along different axes; the end effector 6 is used to grasp the tool 7. After the end effector 6 moves to the tool changing position, the gripper 603 first grasps the tool hub, and after the tool hub is grasped, the gripper 602 extends from the tool shaft to grasp the tool shaft, further enhancing the stability of tool grasping. The end effector of the tool changing robot is equipped with a visual navigation device 601, which is fixedly connected to the end effector of the robot. The visual navigation device 601 is guided by the corresponding visual navigation system inside the visual navigation device 601 to guide the robot's tool movement, and by... Figure 4 The visual monitoring device 9, installed on the shield frame behind the cutterhead, monitors the cutters to determine if their wear exceeds the limit. Cutters with excessive wear need to be replaced. Figure 4 The system includes a tunnel boring machine frame 10, a visual monitoring device 9 installed on the tunnel boring machine frame, and a chamber door 11 on the tunnel boring machine frame for arranging the cutter changer robot to enter and exit the soil chamber.

[0120] Meanwhile, due to the high water pressure, strong impact, and mud splashing in the tool-changing environment, mud and debris easily adhere to the tools and tool removal bolts, affecting the visual monitoring and navigation devices' ability to monitor tool wear and navigate tool removal bolts. Therefore, the end effector of the tool-changing robot is equipped with high-pressure water rinsing. After the end effector moves to the designated position, it first rinses the tools and bolts with high-pressure water until all mud and debris are completely removed. This end effector adds a tool shaft clamping jaw to the gripper. When the tool-changing robot grabs the tool out of the tool box, the tool shaft clamping jaw holds the tool shaft, increasing tool gripping stability and preventing the tool from falling and causing safety accidents in a vibrating environment.

[0121] Specific implementation method 2 for tunnel boring machines:

[0122] like Figure 5 The diagram illustrates the robot-assisted cutter replacement operation flowchart of the shield tunneling machine cutter replacement method proposed in this invention in a practical application scenario. For cutters with excessive wear, a cutter replacement robot performs the operation. During normal tunneling, to avoid affecting the normal operation of the shield machine and to prevent mud and debris from splashing onto the cutter replacement robot and affecting its operational capabilities, the cutter replacement robot retracts into its cabin and keeps the cabin door closed. Before starting the cutter replacement operation, the cutterhead needs to rotate to the cutter replacement position and stop rotating, and the working face is pressurized and stabilized. The pressure inside the robot cabin is increased to balance with the pressure in the excavation cabin, i.e., the pressure inside the robot cabin is adjusted to balance with the pressure in the excavation cabin, and the robot cabin door is opened, allowing the robot to exit the cabin. Based on the position of the cutter to be replaced, the robot position, and the position of obstacles, a feasible route for cutter replacement is calculated. Movement is performed according to the search step size until the end effector of the cutter replacement robot reaches the cutter replacement position, and the robot end effector completes the cutter replacement operation. After completing the cutter replacement operation, the robot returns to the robot cabin, the robot cabin door is closed, and the robot cabin is depressurized.

[0123] Specific implementation method 3 for tunnel boring machines:

[0124] The tunnel boring machine (TBM) with automatic cutter changer has a corresponding cutter changer system, specifically: such as... Figure 6 The diagram shown is a block diagram of a tool-changing robot system for a tunnel boring machine (TBM) in a practical application scenario, as proposed in this invention. The tool-changing robot system includes a control system, a visual navigation device, a robot body, and an end effector. The control system analyzes tool images, workspace images, and path planning space images to determine whether tool wear exceeds limits and to plan feasible paths for the tool-changing robot. Here, this control system and the host computer control system are the same control system. The visual navigation system provides guidance for the tool-changing robot's operation. The end effector includes a visual navigation system with hand-eye calibration to provide guidance for the tool-changing robot's operation.

[0125] This system enables safe and efficient tool wear monitoring and replacement. By using two vision systems and a tool-changing robot, tool wear monitoring and replacement are performed, eliminating the transition time required for manual pressure environment operations, ensuring construction safety, and improving construction efficiency.

[0126] In summary, compared with existing technologies, the above-mentioned method for changing cutterheads in tunnel boring machines (TBMs) and the use of TBMs with automatic cutterhead changing solve the problems of high difficulty, low efficiency, and high safety risks associated with manual cutterhead wear detection and replacement. It achieves automatic cutterhead monitoring and replacement, eliminates the transition time of manual pressure environment operations, ensures construction safety, and improves safety efficiency.

Claims

1. A method for changing cutterheads in a tunnel boring machine, characterized in that, Includes the following steps: 1) When the shield machine detects that the cutter has worn beyond the limit, obtain the point cloud data of the working space where the preset cutter replacement operation path planning needs to be performed, and determine the location of the obstacle and the location of the cutter to be replaced. 2) Determine the current position of the tool-changing robot, and based on the current position of the tool-changing robot and the position of the obstacles, adjust the workspace to the path planning space between the current position of the tool-changing robot and the position of the tool, and determine the current complexity coefficient based on the obstacle situation in the current path planning space; set the current search step size based on the current complexity coefficient; the current search step size is inversely proportional to the current complexity coefficient; 3) Starting from the current position of the tool changing robot and ending at the position of the tool to be replaced, the next position of the tool changing robot is obtained by calling the preset path planning algorithm based on the current search step size. 4) Repeat steps 2) and 3) with the next position of the tool changing robot as the current position of the tool changing robot until the next position of the tool changing robot meets the tool changing conditions, generate a feasible path, so that the tool changing robot can reach the tool position of the tool to be replaced according to the feasible path and perform the tool changing operation.

2. The cutterhead replacement method for a tunnel boring machine according to claim 1, characterized in that, The current complexity coefficient is determined by the ratio between the total volume of obstacles in the current path planning space and the volume of the current path planning space.

3. The cutterhead replacement method for a tunnel boring machine according to claim 2, characterized in that, The current complexity coefficient is calculated using the following formula: Where K is the current complexity coefficient; V obs V represents the total volume of obstacles in the current path planning space. spa Plan the spatial volume for the current path.

4. The cutterhead replacement method for a tunnel boring machine according to any one of claims 1-3, characterized in that, The current search step size is calculated using the following formula, based on the current complexity coefficient: Where λ is the current search step size; K is the current complexity coefficient; S base d is the reference step size for the tool-changing robot. |q-qs| The distance between the current position q of the tool-changing robot and the tool position qs is given.

5. The cutterhead replacement method for a tunnel boring machine according to any one of claims 1-3, characterized in that, The tool changing condition is that the distance between the next position of the tool changing robot and the tool position is less than a preset distance threshold for performing the tool changing operation.

6. The cutterhead replacement method for a tunnel boring machine according to claim 1, characterized in that, Wear monitoring of cutters in tunnel boring machines is performed using the following steps: Acquire point cloud data of the cutting tools during the tunnel boring machine's excavation process; The wear depth of the tool is calculated based on the point cloud data of the tool; when the wear depth of the tool is greater than the preset tool wear depth threshold, the tool is identified as a tool with excessive wear.

7. The cutterhead replacement method for a tunnel boring machine according to claim 6, characterized in that, When the cutting tool is a hob, the symmetry state of the hob is analyzed when calculating the wear depth of the hob. When the tool wears symmetrically, the wear depth of the tool is calculated using the following formula: Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; right The height difference between the deepest wear point on the right side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; When the tool wears asymmetrically, and the wear on the left side is greater than that on the right side, the wear depth of the tool is calculated using the following formula: Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob's cutting edge cross-section and the highest point of the cutting edge on the hob's centerline; right The height difference between the deepest wear point on the right side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; When the tool wears asymmetrically, and the wear on the left side is less than that on the right side, the wear depth of the tool is calculated using the following formula: Where ω is the wear depth of the tool; Y left Y is the height difference between the deepest wear point on the left side of the hob cutting edge cross-section and the apex of the cutting edge on the cross-section; right It is the height difference between the deepest wear on the right side of the hob's cutting edge section and the highest point of the cutting edge on the hob's centerline.

8. A tunnel boring machine, characterized in that, The device includes a cutter-changing robot and a first device for acquiring point cloud data of a pre-defined workspace for which a cutter-changing operation path needs to be planned; the cutter-changing robot is used to execute the cutter-changing method of a tunnel boring machine capable of automatic cutter changing as described in any one of claims 1-7, so that the tunnel boring machine performs a cutter-changing operation through the cutter-changing robot.

9. The tunnel boring machine according to claim 8, characterized in that, This includes a second device for acquiring point cloud data of the cutting tools during the tunnel boring machine's excavation process.

Images