A robot milling processing system and method for large-sized curved thin-walled parts

Abstract

The present invention relates to the technical field of large thin-walled part processing, and particularly relates to a robot milling processing system and method for large curved thin-walled parts. The system includes a flexible fixture unit, a robot milling unit, a tracking and measuring unit, a safety protection unit, and a control unit; the robot milling unit is installed on one side of the flexible fixture unit fixed to the ground, the tracking and measuring unit is installed beside the robot milling unit, the safety protection unit surrounds the flexible fixture unit, the robot milling unit, and the tracking and measuring unit, and the control unit is fixed outside the safety protection unit. The present invention improves the workpiece clamping efficiency and the robot processing accuracy by adaptively clamping the thin-walled part and tracking and monitoring the attitude of the end milling spindle during the robot milling process. The safety protection unit mainly realizes the separation of humans and machines to ensure the safety of personnel and equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of large thin-walled part machining, and particularly to a robot milling machining system and method for large curved thin-walled parts. Background Art

[0002] Large thin-walled parts, such as aircraft skins, rocket fuel tanks, etc., are key parts of major equipment in the fields of aviation, aerospace, etc. Such parts often need to machine a varying number of grid structures with different shapes on one side of the workpiece, and on the premise of ensuring structural strength, minimize the mass of the parts to the greatest extent. Due to the large size, low stiffness, and irregular shape of such parts, it has always been difficult to guarantee their machining quality, and the machining efficiency is also very low. At present, the manufacturing methods for the grid structures of such parts mainly include chemical milling methods and mechanical milling methods, etc. The chemical milling method has disadvantages such as long operation time, high operation cost, low machining accuracy, and difficult treatment of cutting waste liquid. The machining quality and efficiency of the horizontal mechanical milling method have been significantly improved. However, due to the large size of the thin-walled parts, special large horizontal machine tools and matching tooling systems are required for machining, the machining cost is high, and the flexibility of the machine tool and tooling is very poor, making it difficult to handle the machining of large thin-walled parts with multiple varieties and specifications. The robot machining system has good flexibility and can adapt to the application scenarios of multiple specifications of parts. However, it is limited by its insufficient rigidity and inability to directly feedback the end pose, and cannot be adjusted in real time according to the deviation amount during operation. Therefore, it is mainly applied to machining occasions with relatively low machining accuracy requirements. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects existing in the prior art, and mainly provide a robot milling machining system and method for large curved thin-walled parts from two aspects: flexible clamping of large thin parts and improving the machining accuracy of low-rigidity robots.

[0004] The technical solution for achieving the purpose of the present invention is: a robot milling machining system for large curved thin-walled parts, which has a flexible tooling unit, a robot milling unit, a tracking and measuring unit, a safety protection unit, and a control unit; the robot milling unit is installed on one side of the flexible tooling unit fixed to the ground, the tracking and measuring unit is installed beside the robot milling unit, the safety protection unit surrounds the flexible tooling unit, the robot milling unit, and the tracking and measuring unit, and the control unit is fixed outside the safety protection unit.

[0005] Further, the flexible tooling unit includes a tooling frame module, a number of servo flexible support modules, and a number of servo drive modules; the servo flexible support modules are installed inside the tooling frame module, the servo drive module body is installed on the servo flexible support module, and the driving end is fixed to the adjacent servo flexible support module on the left, so that two adjacent servo flexible support modules are connected.

[0006] Further, the tooling frame module is in a "mouth" shape and includes a fixed base. Two columns are fixedly installed at both ends of the fixed base, and a cross beam is installed at the top of the two columns. A linear guide rail is installed on the upper surface of the fixed base and the side surface of the cross beam respectively.

[0007] Further, a number of the servo flexible support modules are installed side by side in the tooling frame module. The servo flexible support module includes a vertical beam. Two sliders are fixedly installed at the top and bottom of the vertical beam respectively, and the sliders are slidably installed on the linear guide rail. A number of servo electric cylinders passing through the vertical beam are arranged on the vertical beam from top to bottom in sequence, and a vacuum adsorption device is arranged at the end of each servo electric cylinder.

[0008] Further, the robot milling unit includes a closed guide rail, a milling robot, a milling spindle, a robot base and a drag chain mechanism; the closed guide rail is fixedly installed parallel to the flexible tooling unit on the ground, the milling robot is movably installed on the closed guide rail through the robot base at the bottom end, and the milling spindle is installed at the end of the milling robot.

[0009] Further, the tracking and measuring unit includes a measuring tracking target and a measuring tracking host; the measuring tracking target is installed on the milling spindle, and the measuring tracking host is installed on the ground beside the robot milling unit.

[0010] Further, the safety protection unit includes aluminum profile columns, aluminum profile safety net sheets and safety doors; a number of the aluminum profile columns and a number of the aluminum profile safety net sheets enclose the flexible tooling unit, the robot milling unit and the tracking and measuring unit, and the safety door is installed between two of the aluminum profile columns.

[0011] Further, a wall part bracket is also installed on the vertical beam.

[0012] A robot milling processing method for large curved thin-walled parts includes the following steps:

[0013] Step 1. According to the theoretical model of the large curved thin-walled part and the preset tooling point information, the flexible tooling unit automatically adjusts the array of the vacuum adsorption devices by an offline program to make the boundary support points of the flexible tooling unit coincide with the theoretical model of the large curved thin-walled part, and the internal support points approach the theoretical model position.

[0014] Step 2. Lift the large curved thin-walled part. During the lifting process, the boundary support points of the flexible tooling first adsorb and fix the workpiece boundary, and then the other support points of the flexible tooling adjust the extension length to achieve adaptive positioning and adsorption and fixation through force feedback.

[0015] Step 3. The milling robot runs the offline program, scans the large curved thin-walled part according to the program path, determines the workpiece boundary and compares the dimensions of the actual model with the theoretical model;

[0016] Step 4. From the results of the scanning and comparison, the workpiece machining area and machining allowance information are obtained. On this basis, the offline programming system plans the machining path and automatically generates the machining program according to the experience database. The path planning can be demonstrated through simulation software, and the operator can view the simulation trajectory to ensure that the path is reasonable and correct;

[0017] Step 5. The milling robot starts to machine the workpiece. At the same time, the tracking and measuring unit tracks and measures the machining attitude of the milling spindle of the milling robot by measuring and tracking the measuring and tracking target installed at the end of the robot, and compensates and adjusts the attitude and process parameters of the subsequent micro-segments of the machining path of the milling robot in real time;

[0018] Step 6. After the workpiece machining is completed, the milling robot runs the detection and scanning program again to detect the machining quality of the workpiece.

[0019] After adopting the above technical solution, the present invention has the following positive effects: (1) The present invention has good flexibility and strong versatility, and can cope with the machining of large thin-walled parts of multiple varieties and specifications.

[0020] (2) The present invention can quickly adjust the tooling clamping according to different curved thin-walled parts, and can also track and monitor the spindle attitude during operation, with full automation, high machining accuracy and fast speed.

[0021] (3) The present invention realizes the separation of man and machine, and the measurement and machining processes are automated without manual intervention, ensuring the safety of personnel and equipment. Brief Description of the Drawings

[0022] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments in conjunction with the drawings, where

[0023] Figure 1 is the schematic diagram of the overall structure of the system of the present invention;

[0024] Figure 2 is the schematic diagram of the specific structure of the flexible tooling unit of the present invention;

[0025] Figure 3 is the schematic diagram of the specific structure of the robot milling unit of the present invention;

[0026] Figure 4 is the schematic diagram of the specific structure of the safety protection unit of the present invention;

[0027] Figure 5 is for the present invention Figure 2Partial enlarged view at position A;

[0028] Figure 6 This invention Figure 2 Partial enlarged view at position B. Detailed implementation method

[0029] (Example 1)

[0030] See Figure 1 , this invention has a flexible tooling unit 100, a robot milling unit 200, a tracking measurement unit 300, a safety protection unit 400 and a control unit 500; the robot milling unit 200 is installed on one side of the flexible tooling unit 100 fixed to the ground, the tracking measurement unit 300 is installed beside the robot milling unit 200, the safety protection unit 400 surrounds the flexible tooling unit 100, the robot milling unit 200 and the tracking measurement unit 300, and the control unit 500 is fixed outside the safety protection unit 400. The control unit 500 is connected to the flexible tooling unit 100, the robot milling unit 200 and the tracking measurement unit 300 through lines to play a control role.

[0031] See Figure 2 , Figure 5 , Figure 6 , the flexible tooling unit 100 includes a tooling frame module 110, 9 servo flexible support modules 120 and 8 servo drive modules 130; the servo flexible support modules 120 are installed in the tooling frame module 110, the body of the servo drive module 130 is installed on the servo flexible support module 120, and the driving end is fixed to the adjacent servo flexible support module 120 on the left, so that two adjacent servo flexible support modules 120 are connected. Linkage is achieved during milling. The tooling frame module 110 is in a "square" shape and includes a fixed base 111. Two columns 112 are installed and fixed at both ends of the fixed base 111, and a cross beam 113 is installed at the top of the two columns 112. A linear guide rail 114 is installed on the upper surface of the fixed base 111 and the side surface of the cross beam 113 respectively. The 9 servo flexible support modules 120 are installed in parallel in the tooling frame module 110. The servo flexible support module 120 includes a vertical beam 121. Two sliders 122 are fixed at the top and bottom of the vertical beam 121 respectively. The sliders 122 are slidably installed on the linear guide rail 114. Five servo electric cylinders 123 with lead screws passing through the vertical beam 121 are arranged on the vertical beam 121 from top to bottom in sequence. A vacuum adsorption device 124 is provided at the end of each servo electric cylinder 123. A wall part bracket 125 is also installed on the vertical beam 121.

[0032] See Figure 1 , Figure 3, the robotic milling unit 200 includes a closed guide rail 201, a milling robot 202, a milling spindle 203, a robot base 205, and a drag chain mechanism 206; the closed guide rail 201 is fixedly installed on the ground in parallel with the flexible tooling unit 100, and the milling robot 202 is movably installed on the closed guide rail 201 through the robot base 205 at the bottom end, and the milling spindle 203 is installed at the end of the milling robot 202. The tracking and measuring unit 300 includes a measuring and tracking target 204 and a measuring and tracking host; the measuring and tracking target 204 is installed on the milling spindle 203, and the measuring and tracking host is installed on the ground beside the robotic milling unit 200.

[0033] See Figure 4 , the safety protection unit 400 includes aluminum profile columns 401, aluminum profile safety net sheets 402, and a safety door 403; several aluminum profile columns 401 and several aluminum profile safety net sheets 402 enclose the flexible tooling unit 100, the robotic milling unit 200, and the tracking and measuring unit 300, and the safety door 403 is installed between 2 aluminum profile columns 401.

[0034] A robotic milling method for large curved thin-walled parts includes the following steps:

[0035] Step 1. According to the theoretical model of the large curved thin-walled part and the preset tooling point information, the flexible tooling unit 100 automatically adjusts the array of the vacuum adsorption device 124 by an offline program through controlling the servo electric cylinder 123, so that the boundary support points of the flexible tooling unit 100 coincide with the theoretical model of the large curved thin-walled part, and the internal support points are close to the theoretical model position.

[0036] Step 2. Lift the large curved thin-walled part. During the lifting process, the boundary support points of the flexible tooling first adsorb and fix the workpiece boundary, and then the remaining support points of the flexible tooling adjust the extension length, and achieve adaptive positioning and adsorption and fixation through force feedback.

[0037] Step 3. The milling robot 202 runs the offline program, scans the large curved thin-walled part according to the program path, determines the workpiece boundary, and compares the size of the actual model with the theoretical model.

[0038] Step 4. From the scanning and comparison results, obtain the workpiece machining area and machining allowance information. On this basis, the offline programming system plans the machining path and automatically generates a machining program according to the experience database. The path planning can be demonstrated through simulation software, and the operator can view the simulation trajectory to ensure that the path is reasonable and correct.

[0039] Step 5. The milling robot 202 starts machining the workpiece. Meanwhile, the tracking and measuring unit 300 tracks and measures the machining posture of the milling spindle 203 of the milling robot 202 by measuring and tracking the measuring and tracking target 204 installed at the end of the robot, and compensates and adjusts the posture and process parameters of the subsequent micro-segments of the machining path of the milling robot 202 in real time;

[0040] Step 6. After the workpiece machining is completed, the milling robot 202 runs the detection and scanning program again to detect the machining quality of the workpiece.

[0041] The working principle of the present invention is as follows: According to the theoretical model of the large curved surface thin-walled part, the flexible tooling unit 100 automatically adjusts the array of the vacuum adsorption device 124 by an offline program, so that each support point of the flexible tooling unit 100 coincides with the theoretical model of the large curved surface thin-walled part. Then, the operator hoists the large curved surface thin-walled part to the tooling position of the flexible tooling unit 100, and the vacuum adsorption device 124 array works in accordance with the steps of first boundary adsorption and then adaptive adsorption to firmly adsorb the workpiece. Next, the milling robot 202 runs the offline program, presets the offline program according to the workpiece model, scans the large curved surface thin-walled part according to the program path, determines the workpiece boundary and compares the actual model with the theoretical model. From the scanning and comparison results, the machining program of the milling robot 202 is confirmed.

[0042] Then, the milling robot 202 starts machining the workpiece. Meanwhile, the tracking and measuring unit 300 tracks and measures the machining posture of the milling spindle 203 of the milling robot 202, and compensates and adjusts the posture and process parameters of the subsequent micro-segments of the machining path of the milling robot 202 in real time. During the workpiece machining process, after the workpiece machining is completed, the milling robot 202 runs the detection and scanning program again to detect the machining quality of the workpiece.

[0043] In the above specific embodiments, the purpose, technical solution and beneficial effects of the present invention are further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A robotic milling method for large-scale curved thin-walled parts, characterized in that: It includes a milling processing system, which has a flexible tooling unit (100), a robotic milling unit (200), a tracking and measuring unit (300), a safety protection unit (400) and a control unit (500); the robotic milling unit (200) is installed on one side of the flexible tooling unit (100) fixed to the ground, the tracking and measuring unit (300) is installed beside the robotic milling unit (200), the safety protection unit (400) encloses the flexible tooling unit (100), the robotic milling unit (200) and the tracking and measuring unit (300), and the control unit (500) is fixed outside the safety protection unit (400); The flexible tooling unit (100) includes a tooling frame module (110), a number of servo flexible support modules (120) and a number of servo drive modules (130). A number of the servo flexible support modules (120) are installed side by side in the tooling frame module (110). The tooling frame module (110) is in the shape of a "square", including a fixed base (111). Two columns (112) are installed and fixed at both ends of the fixed base (111). A cross beam (113) is installed at the top of the two columns (112). A linear guide rail (114) is installed on the upper surface of the fixed base (111) and the side surface of the cross beam (113); The servo flexible support module (120) includes a vertical beam (121). Two sliders (122) are fixed at the top and bottom ends of the vertical beam (121). The sliders (122) are slidably installed on the linear guide rail (114). A number of servo electric cylinders (123) with lead screws passing through the vertical beam (121) are arranged on the vertical beam (121) from top to bottom. A vacuum adsorption device (124) is provided at the end of each servo electric cylinder (123); The robotic milling unit (200) includes a closed guide rail (201), a milling robot (202), a milling spindle (203), a robot base (205) and a drag chain mechanism (206); the closed guide rail (201) is fixedly installed parallel to the flexible tooling unit (100) on the ground. The milling robot (202) is movably installed on the closed guide rail (201) through the robot base (205) at the bottom end. The milling spindle (203) is installed at the end of the milling robot (202); The tracking and measuring unit (300) includes a measuring and tracking target (204) and a measuring and tracking host; the measuring and tracking target (204) is installed on the milling spindle (203), and the measuring and tracking host is installed on the ground beside the robotic milling unit (200); It includes the following steps: Step 1. According to the theoretical model of the large curved thin-walled part and the preset tooling point information, the flexible tooling unit (100) automatically adjusts the array of the vacuum adsorption devices (124) by the offline program through controlling the servo electric cylinders (123), so that the support points at the boundaries of the flexible tooling unit (100) coincide with the theoretical model of the large curved thin-walled part, and the internal support points are close to the theoretical model positions; Step 2. Lift the large curved thin-walled part. During the lifting process, the boundary support points of the flexible tooling first adsorb and fix the workpiece boundary, and then the remaining support points of the flexible tooling adjust the extension length to achieve adaptive positioning and adsorption fixation through force feedback; Step 3. The milling robot (202) runs the offline program, scans the large curved thin-walled part according to the program path, determines the workpiece boundary and compares the dimensions of the actual model with the theoretical model; Step 4. From the scanning and comparison results, obtain the workpiece machining area and machining allowance information. On this basis, the offline programming system plans the machining path and automatically generates the machining program according to the empirical database. The path planning can be demonstrated through simulation software, and the operator can view the simulation trajectory to ensure that the path is reasonable and correct; Step 5. The milling robot (202) starts to machine the workpiece. At the same time, the tracking and measurement unit (300) measures and tracks the measurement and tracking target (204) installed at the end of the robot to track and measure the machining attitude of the milling spindle (203) of the milling robot (202), and compensates and adjusts the attitude and process parameters of the subsequent machining path micro-segments of the milling robot (202) in real time; Step 6. After the workpiece machining is completed, the milling robot (202) runs the detection and scanning program again to detect the machining quality of the workpiece.

2. A robotic milling method for large curved thin-walled parts according to claim 1, characterized in that: The servo flexible support module (120) is installed in the tooling frame module (110), and the body of the servo drive module (130) is installed on the servo flexible support module (120), and the drive end is fixed to the adjacent servo flexible support module (120) on the left, so that two adjacent servo flexible support modules (120) are connected.

3. A robotic milling method for large curved thin-walled parts according to claim 1, characterized in that: The safety protection unit (400) includes aluminum alloy column (401), aluminum alloy safety net sheet (402), and safety door (403); several aluminum alloy columns (401) and several aluminum alloy safety net sheets (402) enclose the flexible tooling unit (100), the robot milling unit (200), and the tracking and measurement unit (300), and the safety door (403) is installed between 2 aluminum alloy columns (401).

4. A robotic milling method for large curved thin-walled parts according to claim 1, characterized in that: A wall part bracket (125) is also installed on the vertical beam (121).

Images