A reliability analysis method for positioning accuracy of a shield cutter changing robot

Abstract

The application provides a reliability analysis method for positioning accuracy of a shield tool changing robot, realizes sensitivity analysis of error parameters by constructing a kinematic model and an error proxy model, and accurately evaluates the failure probability of positioning accuracy. The assembly and machining errors are comprehensively considered, the error parameters are treated as random variables, the accuracy and efficiency of the analysis are improved. The mean and standard deviation of the random variable are used for sensitivity calculation, and a failure calculation method of positioning accuracy sensitivity is obtained, which provides an important basis for optimization design. The application not only helps to reduce the tool changing time, improve the construction efficiency and reduce the safety risk, but also provides an accurate and reliable tool changing robot manufacturing scheme for designers. The method has universality and flexibility, and can be widely applied to performance improvement and fault prevention of the shield tool changing robot. The implementation of the application will promote the development of shield construction technology and provide strong support for industrial automation and efficient production.

Description

Technical Field

[0001] This invention relates to the field of reliability analysis technology, and in particular to a reliability analysis method for the positioning accuracy of a tunnel boring machine cutter changer robot. Background Technology

[0002] The importance of the tunnel boring machine (TBM) as the core equipment in tunnel boring construction is self-evident. During the tunneling process, the geological environment it faces is ever-changing and unpredictable. This uncertainty places extremely high demands on the cutterhead and cutting tools used in construction. Due to the complexity of the geology, the tools wear out severely during the tunneling process, so multiple cutterhead replacements are often required during a single construction operation.

[0003] Traditional cutterhead changing operations are usually performed manually, but this method has many drawbacks. First, manual cutterhead changing is inefficient and time-consuming, directly impacting the overall project schedule. Second, performing cutterhead changing operations inside the narrow and complex interior of a tunnel boring machine makes it difficult to fully guarantee the personal safety of the operators. To address these issues, researchers and technicians have proposed a solution using cutterhead changing robots to perform autonomous cutterhead changing operations.

[0004] The introduction of cutterhead changing robots has undoubtedly brought revolutionary changes to tunnel boring machine (TBM) construction. Their high-precision positioning capabilities can greatly improve the efficiency of the cutterhead changing process, significantly reduce the time required for changing cutters, and thus improve the overall efficiency of the project. However, with the in-depth application of robotics technology, some challenges and problems have also emerged.

[0005] To meet the assembly requirements of the tool-changing robot and enable the rotational function of the kinematic pairs, a certain amount of clearance is inevitable between the robot's joints. These clearances, along with the flexible deformation of important joints due to load and their own weight, all affect the accuracy of the robot's end effector motion. More complexly, during robot operation, contact and impact wear between the joints can further deform these clearances, leading to a further deterioration in the robot's end effector pose accuracy.

[0006] Therefore, when using robots for cutter replacement operations, the reliability of their positioning accuracy becomes a problem we must face and solve. To improve the positioning accuracy of shield tunneling cutter replacement robots, researchers and technicians need to continuously explore new methods and technologies, such as optimizing the robot's structural design, improving the manufacturing precision of joints, and adopting advanced control systems, to ensure that the robot can stably and accurately complete the cutter replacement task in complex and ever-changing geological environments. Summary of the Invention

[0007] To address the technical problems in the prior art, this invention provides a reliability analysis method for the positioning accuracy of a shield tunneling cutter changer robot.

[0008] The technical solutions provided by the embodiments of the present invention are as follows:

[0009] First aspect:

[0010] This invention provides a reliability analysis method for the positioning accuracy of a tunnel boring machine (TBM) cutterhead changing robot, comprising:

[0011] S1. Establish the kinematic model of the tool-changing robot. The steps include clarifying the robot's DH parameters, establishing the robot's theoretical model and actual model, and finally obtaining the robot's error model.

[0012] S2. Construct a kinematic error surrogate model, including experimental design, building the surrogate model and optimizing the model parameters;

[0013] S3. Perform sensitivity analysis on parameter errors. The steps include organizing the random variables of model errors, obtaining the failure probability from the joint probability density, calculating the mean and variance of the failure probability, solving for the sensitivity factor, and finally obtaining the sensitivity of the error parameters.

[0014] S1 specifically includes:

[0015] S11. The end effector pose of the tool-changing robot includes link length, link offset, link torsion angle, and axis torsion angle. All links of the tool-changing robot are considered rigid bodies, and a coordinate system is established for each link. A rigid body description matrix is ​​obtained through homogeneous transformation. Multiplying all the rigid body description matrices together yields the end effector pose matrix T of the tool-changing robot.

[0016] ;

[0017] In the above formula, Indicates the length of the connecting rod, Indicates link offset, Indicates the link torsion angle and Indicates the angle of twist of the shaft;

[0018] S12. Considering assembly and machining errors, the actual pose of the tool-changing robot is:

[0019] ;

[0020] In the above formula, and These represent the link length error, link offset error, link torsion angle error, and shaft torsion angle error, respectively.

[0021] S13, when and When both are relatively small, it simplifies to a linear equation.

[0022] ;

[0023] In the above formula, and Generally refers to the DH parameters of each axis in a tool-changing robot.

[0024] S3 specifically includes:

[0025] S14. Input the error parameters of each axis of the tool changing robot. and Organize into a single random parameter variable ;

[0026] S22. Define the joint probability density of the variables as... If the error parameters are considered independent of each other, then the joint probability density distribution is obtained by considering all the random parameter variables together as follows:

[0027] ;

[0028] Meanwhile, the failure rate of the tool-changing robot's positioning accuracy is [value missing].

[0029] ;

[0030] In the above formula, The area where the tool-changing robot experiences positioning accuracy failure;

[0031] S23. The process of solving for the sensitivity of the error variable of the tool changing robot is actually the process of calculating the mean and variance partial derivatives of the failure probability of the tool changing robot's positioning accuracy.

[0032] ;

[0033] S24. According to the law of large numbers, the calculation of the positioning accuracy sensitivity failure of the tool-changing robot can be expressed as follows:

[0034] ;

[0035] In the above formula, They are mutually independent random variables, including the mean. and standard deviation ,

[0036] ;

[0037] ;

[0038] By taking the partial derivatives with respect to the mean and standard deviation and combining them with the sensitivity failure calculation formula, we can obtain the degree of influence of the failure probability on the mean and standard deviation of the random variable.

[0039] ;

[0040] S25. After obtaining the influence of the mean and standard deviation of each error variable, and Take the absolute value.

[0041] ;

[0042] Then the sensitivity factor of the random parameter is obtained.

[0043] ;

[0044] By analyzing the sensitivity of the positioning accuracy reliability of each tool changer robot on each joint axis, the sensitivity of the tool changer robot to errors on each joint axis is obtained. By comparing the movement error and rotation error at the joint, the sensitivity of joint axis errors is analyzed. For tool changer robots with different configurations, the different configurations result in different sensitivities to error parameters. By analyzing tool changer robots with different configurations, errors can be avoided in the early design stage, thereby improving the reliability of the positioning accuracy of the tool changer robot.

[0045] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0046] (1) In this invention, by improving the positioning accuracy of the shield tunneling cutter replacement robot, the time required for cutter replacement can be significantly reduced, thereby improving construction efficiency. At the same time, robot cutter replacement reduces reliance on manual operation, lowers the safety risks to operators due to long working hours and high-intensity labor, and ensures the safety of the construction process;

[0047] (2) In this invention, the positioning accuracy reliability analysis method provided by this invention can accurately identify the main error sources affecting the positioning accuracy of the robot. This provides designers with an important reference for the robot design and manufacturing stages, helping them to avoid or reduce these errors during the design stage, thereby manufacturing a more accurate and reliable tool-changing robot. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in 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.

[0049] Figure 1 A flowchart illustrating a reliability analysis method for the positioning accuracy of a shield tunneling cutterhead changing robot provided in an embodiment of the present invention;

[0050] Figure 2This is a schematic diagram of the linkage parameter definition for a reliability analysis method of positioning accuracy of a shield tunneling cutter changer robot provided in an embodiment of the present invention. Detailed Implementation

[0051] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0052] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0053] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0054] Reference manual attached Figure 1 The diagram shows a flowchart illustrating a reliability analysis method for the positioning accuracy of a shield tunneling cutterhead changing robot provided in an embodiment of the present invention.

[0055] This invention provides a reliability analysis method for the positioning accuracy of a tunnel boring machine (TBM) cutterhead changing robot, which may include the following steps:

[0056] To achieve pose control of the tool-changing robot, a kinematic model needs to be established. This model describes the poses between the robot's links. By multiplying the pose description matrices between each link, the end-effector pose of the tool-changing robot can be obtained. There are many methods for establishing a robot's kinematic model, and these methods are largely similar. This document provides a clear and easy-to-understand modeling method, which can be found in the attached instruction manual. Figure 2 The diagram illustrates the link parameter definition of a reliability analysis method for the positioning accuracy of a tunnel boring machine cutter changer robot according to an embodiment of the present invention. The link parameter definitions are as follows: For along Shaft from Move to distance, To bypass Shaft from Rotate to Angle, For along Shaft from Move to distance, To bypass Shaft from Move to The angle.

[0057] Assuming each link of the tool-changing robot is a rigid body, and establishing a coordinate system for each link, and obtaining a rigid body description matrix through homogeneous transformation, by linking these matrices together and recursively establishing the relationship between the pose of the end effector and the base coordinates, the end effector pose matrix of the tool-changing robot can be obtained.

[0058] For a tool-changing robot, the first step is to determine the pose of the robot's end effector. The robot's end effector pose can be determined by the link length. Linkage offset Linkage torsion angle Rotation angle of the axis There are four parameters in total. By multiplying these homogeneous matrices together, the end effector pose matrix T of the tool-changing robot can be determined.

[0059] ;

[0060] Meanwhile, due to assembly and machining errors, the actual pose of the tool-changing robot will be affected by errors. and Due to the influence of the robot, the actual pose of the tool-changing robot at this time is:

[0061] ;

[0062] When the errors are relatively small, it can be simplified into a linear equation:

[0063] ;

[0064] in, and The term "DH parameter" generally refers to the DH parameters of each axis in a tool-changing robot. By performing sensitivity analysis on the error parameters of each axis in the formula, the impact of each parameter on the reliability of the tool-changing robot can be identified.

[0065] Due to the inherent complexity of the tool-changing robot, it is difficult to directly express the model using mathematical models, and directly solving it using a real model is even more impossible. Therefore, a surrogate model is needed to replace the original model. A surrogate model is an approximate mathematical model that can replace complex and time-consuming numerical analysis in optimization design. It can also be called a response surface model or an approximate model. In sensitivity optimization design, it is inevitable to encounter objective functions that are difficult to express intuitively. In such cases, a surrogate model can be used to replace the objective function, thereby greatly improving the efficiency of optimization design and reducing the difficulty of optimization. Therefore, establishing a surrogate model to replace the original complex problem model reduces computational costs and improves computational efficiency.

[0066] After establishing a proxy model for the positioning accuracy reliability of the tool changer robot, the error parameters of each axis of the tool changer robot are... and Organize into a single random parameter variable The joint probability density of the variables is defined as follows: In practical engineering, it is assumed that the various error parameters are independent of each other, and the joint probability density distribution is obtained by combining the random parameter variables.

[0067] ;

[0068] The probability of positioning accuracy failure in the tool-changing robot is:

[0069] ;

[0070] The process of solving for the sensitivity of the error variables of the tool changing robot in the region where the positioning accuracy of the robot fails is actually the process of calculating the mean and variance partial derivative of the robot's positioning accuracy failure probability.

[0071] ;

[0072] By obtaining the end-effector error distribution of the shield tunneling cutter changer robot in the surrogate model, and then predicting the failure probability of the cutter changer robot's positioning accuracy, the calculation of the failure of the cutter changer robot's positioning accuracy sensitivity can be expressed as follows, according to the law of large numbers:

[0073] ;

[0074] in They are mutually independent random variables, including the mean. and standard deviation ;

[0075] ;

[0076] By taking the partial derivatives of the mean and standard deviation and combining them with the sensitivity failure calculation formula, we can obtain the degree of influence of the failure probability on the mean and standard deviation of the random variable.

[0077] ;

[0078] After obtaining the influence of the mean and standard deviation of each error variable, and We can get the result by taking the absolute value;

[0079] ;

[0080] The sensitivity factor of the random parameter can be obtained;

[0081] ;

[0082] By analyzing the sensitivity of the robot's positioning accuracy reliability across each joint axis, the sensitivity of the tool-changing robot to errors on each joint axis can be determined. The sensitivity of joint axis errors can be analyzed by comparing the translational and rotational errors at the joints. Different tool-changing robot configurations result in varying sensitivities to error parameters. Analyzing different configurations allows for the avoidance of these errors during the initial design phase, thereby improving the positioning accuracy reliability of the tool-changing robot.

[0083] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0084] (1) In this invention, by improving the positioning accuracy of the shield tunneling cutter replacement robot, the time required for cutter replacement can be significantly reduced, thereby improving construction efficiency. At the same time, robot cutter replacement reduces reliance on manual operation, lowers the safety risks to operators due to long working hours and high-intensity labor, and ensures the safety of the construction process;

[0085] (2) In this invention, the positioning accuracy reliability analysis method provided by this invention can accurately identify the main error sources affecting the positioning accuracy of the robot. This provides designers with an important reference for the robot design and manufacturing stages, helping them to avoid or reduce these errors during the design stage, thereby manufacturing a more accurate and reliable tool-changing robot.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0087] The following points need to be explained:

[0088] (1) The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention. Other structures can refer to the general design.

[0089] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the invention, i.e., these drawings are not drawn to scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0090] (3) Where there is no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0091] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A reliability analysis method for the positioning accuracy of a shield tunneling cutterhead changing robot, characterized in that, include: S1. Establish the kinematic model of the tool-changing robot. The steps include clarifying the robot's DH parameters, establishing the robot's theoretical model and actual model, and finally obtaining the robot's error model. S2. Construct a kinematic error surrogate model, including experimental design, building the surrogate model and optimizing the model parameters; S3. Perform sensitivity analysis on parameter errors. The steps include organizing the random variables of model errors, obtaining the failure probability from the joint probability density, calculating the mean and variance of the failure probability, solving for the sensitivity factor, and finally obtaining the sensitivity of the error parameters. S1 specifically includes: S11. The end effector pose of the tool-changing robot includes link length, link offset, link torsion angle, and axis torsion angle. All links of the tool-changing robot are considered rigid bodies, and a coordinate system is established for each link. A rigid body description matrix is ​​obtained through homogeneous transformation. Multiplying all these rigid body description matrices yields the end effector pose matrix T of the tool-changing robot. ; In the above formula, Indicates the length of the connecting rod, Indicates link offset, Indicates the link torsion angle and Indicates the angle of twist of the shaft; S12. Considering assembly and machining errors, the actual pose of the tool-changing robot is: ; In the above formula, and These represent the link length error, link offset error, link torsion angle error, and shaft torsion angle error, respectively. S13, when and When both are relatively small, it simplifies to a linear equation. ; In the above formula, and Generally refers to the DH parameters of each axis in a tool-changing robot.

2. The reliability analysis method for the positioning accuracy of a shield tunneling cutterhead changing robot according to claim 1, characterized in that, S3 specifically includes: S14. Input the error parameters of each axis of the tool changing robot. and Organize into a single random parameter variable ; S22. Define the joint probability density of the variables as... If the error parameters are considered independent of each other, then the joint probability density distribution is obtained by considering all the random parameter variables together as follows: ; Meanwhile, the failure rate of the tool-changing robot's positioning accuracy is [value missing]. ; In the above formula, The area where the tool-changing robot experiences positioning accuracy failure; S23. The process of solving for the sensitivity of the error variable of the tool changing robot is actually the process of calculating the mean and variance partial derivatives of the failure probability of the tool changing robot's positioning accuracy. ; S24. According to the law of large numbers, the calculation of the positioning accuracy sensitivity failure of the tool-changing robot can be expressed as follows: ; In the above formula, They are mutually independent random variables, including the mean. and standard deviation , ; By taking the partial derivatives with respect to the mean and standard deviation and combining them with the sensitivity failure calculation formula, we can obtain the degree of influence of the failure probability on the mean and standard deviation of the random variable. ; S25. After obtaining the influence of the mean and standard deviation of each error variable, and Take the absolute value. ; Then the sensitivity factor of the random parameter is obtained. ; By analyzing the sensitivity of the positioning accuracy reliability of each tool changer robot on each joint axis, the sensitivity of the tool changer robot to errors on each joint axis is obtained. By comparing the movement error and rotation error at the joint, the sensitivity of joint axis errors is analyzed. For tool changer robots with different configurations, the different configurations result in different sensitivities to error parameters. By analyzing tool changer robots with different configurations, errors can be avoided in the early design stage, thereby improving the reliability of the positioning accuracy of the tool changer robot.

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