A method for machine tool and robot collaborative machining of large thin-walled cylindrical components

Abstract

The application is a kind of method for large thin-walled cylinder component machine tool and robot collaborative processing, characterized in that it comprises the following steps: step one, establishing the hardware configuration of the system; step two, calibrating the system; step three, based on the above matrix transformation relationship, the relative position and posture in the component coordinate system {PF} and the robot coordinate system {BF} are calculated by formula; step four, after obtaining the calibration result, the component is milled. Therefore, the positioning accuracy of robot offline programming is improved by relying on the accuracy of the machine tool, and the processing efficiency is improved. In addition, by calibrating the position relationship between the robot and the component through the machine tool, the limitations during robot calibration are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automatic assembly, and discloses a method for machining large thin-walled cylindrical components by machine tools and robots in cooperation. BACKGROUND

[0002] The large thin-walled cylindrical component belongs to a typical large thin-walled multi-cylinder segment welded combined structure. Due to the machining error of the thin-walled cylinder segment, welding deformation and external environmental factors (such as temperature, humidity, etc.), the actual state of the large thin-walled cylindrical component is inconsistent with the theoretical state. In order to ensure the quality of the final product, some processing features need to be processed before the final assembly of the component.

[0003] The existing processing mode only uses a numerical control machine tool as a processing equipment, and has problems such as complex manufacturing process, long manufacturing cycle, poor quality consistency and the like, and it is difficult to meet the requirements of large batch, high efficiency and high precision production of the component under the current situation. However, the robot has strong spatial accessibility and operational flexibility, but its movement range is also limited to a certain extent when processing large components, and only the local position of the component can be calibrated, so it is difficult to meet the final processing precision requirements. SUMMARY

[0004] In view of the existing processing mode for the large thin-walled cylindrical component, the purpose of the present application is to provide a method for machining large thin-walled cylindrical components by machine tools and robots in cooperation, so as to improve the processing efficiency and processing precision.

[0005] A method for machining large thin-walled cylindrical components by machine tools and robots in cooperation, characterized by using a system for machining large thin-walled cylindrical components by machine tools and robots in cooperation, which comprises a numerical control machine tool 3, a large thin-walled cylindrical component 4, an industrial robot 1 and a milling end 2; the industrial robot 1 is loaded with a milling executor 2 at the end, and the industrial robot 1 is fixed on the ground outside the end side of the large thin-walled cylindrical component 4; the milling executor 2 adopts an electric spindle for milling processing, and the speed is set according to the requirements, and a circulating coolant is provided for the electric spindle of the milling executor through a liquid cooling machine to ensure the service life.

[0006] The method for machining large thin-walled cylindrical components by machine tools and robots in cooperation comprises the following steps:

[0007] Step 1: establish the hardware configuration of the system, including the numerical control machine tool, the large thin-walled cylindrical component, the industrial robot and the milling end installed on the robot;

[0008] Step 2: calibrate the system, and mark the machine tool coordinate system, the component coordinate system, the robot coordinate system and the tool coordinate system as {MF}, {PF}, {BF} and {TF} respectively, solve the matrix transformation relationship between {MF} and {PF}, {MF} and {BF}, and {BF} and {TF} respectively, and obtain

[0009] The tool coordinate system {TF} is calibrated using the four-point method. A pointed cone is installed on the robot's main axis. The robot is operated to touch the pointed cone block, which is stably placed near the robot, in four different postures, and samples are taken. The calculation method is as follows:

[0010] The relationships between the robot coordinate system, flange coordinate system, and tool coordinate systems {BF}, {FF}, and {TF} are as follows: Expanding the relationship, we get:

[0011]

[0012] Transform into: In the formula, p T0 The translation vector of the tool coordinate system in the robot coordinate system remains constant. Let be the rotation matrix of the tool coordinate system in the robot coordinate system. for The rotation matrix of the flange coordinate system in the robot coordinate system, p Fi Let be the translation vector of the flange coordinate system in the robot coordinate system. p is the rotation matrix of the tool coordinate system in the flange coordinate system. t Let p be the translation vector of the tool coordinate system in the flange coordinate system. When i = 4, p can be solved. t The value of .

[0013] Step 3: Based on the above matrix transformation relationships, the relative poses in the component coordinate system {PF} and the robot coordinate system {BF} are calculated using the formula.

[0014] Step 4: After obtaining the calibration results, place the robot, milling end effector, and component in the offline programming software according to their relative poses. Using the component coordinate system {PF} as the world coordinate system, generate the tool's machining trajectory and perform milling on the component.

[0015] In step one, the industrial robot can be equipped with end effectors of different functions to complete the processing of components with various features.

[0016] In step two, the matrix transformation relationship between {BF} and {TF} can be obtained using the four-point method, and its calculation process is performed analytically by the robot.

[0017] In step three, the relative poses of the component coordinate system {PF} and the robot coordinate system {BF} are determined by calibrating the component and the robot base using a machine tool, thus avoiding inaccuracies when calibrating the component with the robot.

[0018] In step four, the reachable range and machining trajectory of the robot with different end effectors are simulated and analyzed by offline programming software to ensure the correctness and safety in actual machining.

[0019] The beneficial effects of the present application are as follows: the present application can calibrate the system, and the machine tool coordinate system, the component coordinate system, the robot coordinate system and the tool coordinate system are respectively {MF}, {PF}, {BF} and {TF}, the matrix transformation relationship between {MF} and {PF}, {MF} and {BF} and {BF} and {TF} is solved respectively, and Therefore, the relative pose in the component coordinate system {PF} and the robot coordinate system {BF} can be calculated by formula After obtaining the calibration result, the robot, the milling end and the component are placed in the offline programming software according to the relative pose relationship, the machining trajectory of the cutter is generated with the component coordinate system {PF} as the world coordinate system, and the milling machining of the component is performed.

[0020] Therefore, the present application can process various features on large thin-walled cylindrical components, and the matrix conversion of the numerical control machine tool is used to realize the accurate calibration between the robot and the component. The present application is suitable for feature processing on large thin-walled cylindrical components, and the processing mode combining the machine tool and the robot saves the machine tool time cost, improves the positioning accuracy of the robot offline programming by relying on the machine tool accuracy, and improves the processing efficiency. In addition, the position relationship between the robot and the component is calibrated by the machine tool, which avoids the limitation of robot calibration. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Fig. 1 is a system structure schematic diagram of the present application.

[0022] In the figure: 1 is an industrial robot, 2 is a milling end effector, 3 is a numerical control machine tool, and 4 is a large thin-walled cylindrical component. DETAILED DESCRIPTION

[0023] The method for machine tool and robot collaborative processing of large thin-walled cylindrical components according to the present application comprises the following steps:

[0024] S1. Establish the hardware configuration of the system, including the numerical control machine tool, the large thin-walled cylindrical component, the industrial robot and the milling end installed on the robot;

[0025] S2. Calibrate the system, and the machine tool coordinate system, the component coordinate system, the robot coordinate system and the tool coordinate system are respectively {MF}, {PF}, {BF} and {TF}, the matrix transformation relationship between {MF} and {PF}, {MF} and {BF} and {BF} and {TF} is solved respectively, and

[0026] S3. Based on the above matrix transformation relationship, the relative pose of the component coordinate system {PF} and the robot coordinate system {BF} is calculated by using the formula

[0027] S4. After obtaining the calibration result, the robot, the milling end and the component are placed in the offline programming software according to the relative pose relationship, the machining trajectory of the tool is generated in the component coordinate system {PF} as the world coordinate system, and the milling machining of the component is performed.

[0028] Preferably, the industrial robot in step S1 can be matched with different function end effectors to complete the machining of components with multiple features.

[0029] Preferably, the matrix transformation relationship between {BF} and {TF} in step S2 can be obtained by four-point method, and the calculation process is analyzed and calculated by the robot internally.

[0030] Preferably, the relative pose of the component coordinate system {PF} and the robot coordinate system {BF} in step S3 is obtained by respectively performing datum alignment on the component and the robot base of the machine tool, which avoids the inaccuracy of the robot calibration component.

[0031] Preferably, in step S4, the reachable range and machining trajectory of the robot when installing different end effectors are simulated and analyzed by the offline programming software, which ensures the correctness and safety in actual machining.

[0032] Embodiment one:

[0033] The application will be further described below with reference to the accompanying drawings.

[0034] Figure 1 The system for machine tool and robot collaborative machining of large thin-walled cylindrical components has the following characteristics and functions: the industrial robot 1 is loaded with a milling end effector 2, the milling end effector 2 adopts an electric spindle for milling machining, the rotating speed can be set according to the demand, and the electric spindle is provided with circulating cooling liquid by a liquid cooling machine to ensure the service life; the industrial robot 1 processes the features on the end face and inner cavity of the large thin-walled cylindrical component 4, and the numerical control machine tool 3 processes the features on other parts of the large thin-walled cylindrical component 4.

[0035] The system for machine tool and robot collaborative machining of large thin-walled cylindrical components includes the following steps:

[0036] S1. Establish the hardware configuration of the system, including the numerical control machine tool, the large thin-walled cylindrical component, the industrial robot, and the milling end installed on the robot; the robot mills the features on the end face and inner cavity of the large thin-walled cylindrical component, and the numerical control machine tool processes the features on other parts of the large thin-walled cylindrical component.

[0037] S2. Calibration system, machine tool coordinate system, component coordinate system, robot coordinate system, flange coordinate system, tool coordinate system are {MF}, {PF}, {BF}, {FF}, {TF} respectively.

[0038] Calibrate tool coordinate system {TF} by four-point method, install a sharp cone on the robot spindle, operate the robot to touch the sharp cone block placed stably near the robot in four different postures, and sample, the calculation method is as follows:

[0039] The relationship between robot coordinate system, flange coordinate system, tool coordinate system {BF}, {FF}, {TF} is Expand the relationship as follows:

[0040]

[0041] Transformed as: In the formula, p T0 Fixed, The value of p t Can be obtained by sampling and establishing coordinate system, when i=4, the value of p

[0042] S3. Calibrate component coordinate system {PF} and robot coordinate system {BF} by machine tool reference alignment method, first roughly align the component according to the XYZ direction of numerical control programming, then ensure the parallelism of XYZ of the component and XYZ of the machine tool by table shooting, finally install the measuring head on the machine tool and mark the position of the component through measuring points to obtain Use the formula to solve and calculate the relative pose of component coordinate system {PF} and robot coordinate system {BF}

[0043] Based on the above matrix transformation relationship, use the formula To solve and calculate the relative pose of component coordinate system {PF} and robot coordinate system {BF}

[0044] S4. After obtaining the calibration results, place the robot, milling end and component in the offline programming software according to the relative pose relationship, take the component coordinate system {PF} as the world coordinate system, generate the machining trajectory of the cutter, and mill the component.

Claims

1. A method for machining large thin-walled cylindrical components by a machine tool in cooperation with a robot, characterized in that, The system for machining large thin-walled cylindrical components by machine tool and robot cooperation includes a numerical control machine tool (3), a large thin-walled cylindrical component (4), an industrial robot (1) and a milling end (2); the industrial robot (1) is loaded with a milling executor (2) at the end, and the industrial robot (1) is fixed on the ground outside the end side of the large thin-walled cylindrical component (4); the milling executor (2) uses an electric spindle for milling, sets the rotating speed according to the requirement, and provides circulating cooling liquid for the electric spindle of the milling executor through a liquid cooling machine to ensure the service life; The method for machining large thin-walled cylindrical components by machine tool and robot cooperation includes the following steps: Step one, establish the hardware configuration of the system, including a numerical control machine tool, a large thin-walled cylindrical component, an industrial robot and a milling end installed on the robot; Step two, calibrate the system, machine tool coordinate system, component coordinate system, robot coordinate system, tool coordinate system are {MF}, {PF}, {BF}, {TF} respectively, solve the matrix transformation relationship between {MF} and {PF}, {MF} and {BF}, {BF} and {TF} respectively, get The tool coordinate system {TF} is calibrated by the four-point method, a sharp cone is installed on the robot spindle, the robot is operated to touch the sharp cone block stably placed near the robot in four different postures, and sampling is performed, and the calculation method is as follows: The relationship between the robot coordinate system, the flange coordinate system, the tool coordinate system {BF}, {FF}, {TF} is The relationship is unfolded as follows: Transformed into: p in the formula T0 is a translation vector of the tool coordinate system in the robot coordinate system, is a rotation matrix of the tool coordinate system in the robot coordinate system, is a translation vector of the flange coordinate system in the robot coordinate system, is a rotation matrix of the flange coordinate system in the robot coordinate system, Fi is a translation vector of the flange coordinate system in the robot coordinate system, is a rotation matrix of the tool coordinate system in the flange coordinate system, t is a translation vector of the tool coordinate system in the flange coordinate system, t the value of p can be solved when i = 4. Step three, based on the above matrix transformation relationship, the formula is used to calculate the relative pose of the component coordinate system {PF} and the robot coordinate system {BF} Step four, after obtaining the calibration results, place the robot, the milling end and the component in the offline programming software according to the relative pose relationship, take the component coordinate system {PF} as the world coordinate system, generate the machining trajectory of the cutter, and mill the component.

2. The method according to claim 1, wherein, The industrial robot in step one can be matched with different function end executors to complete the machining of components with multiple features.

3. The method according to claim 1, wherein, The matrix transformation relationship between {BF} and {TF} in step two can be obtained by the four-point method, and the calculation process is analyzed and calculated by the robot internally.

4. The method for the machine tool and robot collaborative machining of large thin-walled cylindrical components according to claim 1, characterized in that, The relative pose between the component coordinate system {PF} and the robot coordinate system {BF} in step three is found by the machine tool respectively on the component and the robot base, which avoids the inaccuracy when the robot calibrates the component.

5. The method for the machine tool and robot collaborative machining of large thin-walled cylindrical components according to claim 1, characterized in that, In step four, the offline programming software is used to simulate and analyze the reachable range and machining trajectory of the robot when different end executors are installed, which ensures the correctness and safety in actual machining.

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