Manufacturing method for automatic polishing system for complex special-shaped thin-wall skin

Abstract

The invention discloses a manufacturing method for an automatic polishing system for a complex special-shaped thin-wall skin. The manufacturing method comprises the following steps that (1) a polishing head module is designed; (2) a six-axis robot is arranged; (3) designing a supporting vehicle module; (4) planning a polishing path; and (5) starting a polishing working procedure. The intelligent machining design concept is added, the force control technology, the vision technology, the software technology and the like are fused in grinding equipment, the automatic robot technology, the grinding automatic alignment planning technology, the automatic photographing positioning technology and the like are specifically included, and automatic grinding of the thin-wall skin of the aviation product is achieved; in the grinding process, attitude force / position mixed control compensation is carried out according to contact force of the tail ends of the grinding heads and product contact parts, accuracy and stability of the contact force of the grinding heads are guaranteed, meanwhile, self-adaptive stretching and retracting can be carried out according to contour features of the surfaces of the products, rapid movement between the grinding heads and the contact surfaces is achieved, and the grinding efficiency is improved. And the grinding head is quickly replaced and mounted through the design of a positioning buckle.

Description

Technical Field

[0001] The invention belongs to the technical field of surface grinding treatment of heterogeneous thin-wall shells such as titanium alloys, high-temperature alloys, and resin-based composite materials, and relates to a manufacturing method for an automatic grinding system for complex and heterogeneous thin-wall skins. Background Art

[0002] With the continuous innovation of aviation products, the structural shape of the products is becoming more and more complex. The performance of the materials used in the outer skin is gradually developing towards high hardness, high modulus, and multi-function. Among them, titanium alloys, high-temperature alloys, and composite materials are typical representatives of materials used in aviation products. In addition, the product structure design is complex, and the construction of each process is frequently crossed. If the surface treatment methods such as pickling and sandblasting are adopted, it is not realistic. Laser cleaning is easy to damage the electronic components installed inside the product due to the high instantaneous temperature. Therefore, the current production method of surface treatment in the workshop is still using grinding. Manual grinding is labor-intensive, and the grinding quality depends entirely on the experience of the operator. Automated grinding is difficult to be truly applied because the grinding head is difficult to adapt to the complex skin structure. Therefore, the skin surface treatment method seriously restricts the mass production of aviation products. Summary of the invention

[0003] (I) Purpose of the invention

[0004] The purpose of the present invention is to provide a manufacturing method for an automated grinding system for complex and special-shaped thin-walled skins, to achieve automated grinding of complex and special-shaped thin-walled skins of aviation products, to improve grinding efficiency, to solve the problem of low yield rate of manual grinding, and to meet the flexible grinding requirements of special structures and materials such as aviation products.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a manufacturing method for an automated grinding system for complex and irregular thin-walled skins, comprising the following steps:

[0007] (1) Design of the grinding head module: The grinding head module is mainly composed of seven independent radial floating spindles and force control integrated actuators. The seven independent radial floating spindles are arranged to form a circular grinding disc. Each radial floating spindle contains a drive motor and a frequency converter. The force sensor at the top of each radial floating spindle realizes high-precision force control adjustment. The front end of each force sensor transmits contact pressure through a follower ball. The structure of the force sensor at the top of the radial floating spindle is similar to the head of a cylindrical pen core. Each radial floating spindle is equipped with a detachable grinding head. The grinding head is similar to a screw-shaped cylinder with a rod. The rod of the grinding head is assembled with the radial floating spindle by means of sleeve insertion. After the grinding head and the radial floating spindle are assembled in place, they are positioned and locked by means of a snap-on method. The snap-on method can be quickly opened and installed after being pressed, which facilitates the replacement of the grinding head during the grinding process.

[0008] The force control integrated actuator controls the rotation, attitude adjustment, motion state and telescopic stroke of each radial floating spindle. The force control integrated actuator mainly includes attitude sensor, position sensor, acceleration sensor, force sensor and control system. When the attitude sensor contacts and moves with the surface of the grinding head and the workpiece, the force sensor of each grinding head first determines the contact force between the grinding head and the workpiece through contact pressure perception; the attitude sensor detects the position of the equipment; the position sensor detects the stroke position of the grinding head; the acceleration sensor determines the motion state of the grinding head; the control system collects the information fed back by each sensor, outputs the control signal through the force control algorithm, and the control signal electronic module regulator controls the rotation, attitude, telescopic stroke, etc. of each grinding head to achieve grinding of the workpiece.

[0009] (2) Six-axis robot layout: The grinding head module is installed on the six-axis robot. The six-axis robot used in this patent is a mature product on the market. The grinding head system can realize multi-directional and multi-angle rotation on the head of the six-axis robot. The six-axis robot consists of a control cabinet, a teach pendant, and a robot body. The control cabinet is used to control the movement and posture of the robot; the teach pendant is used to execute the operation program and parameter configuration related to the operation and robot; the robot body is mainly composed of six joint axes, which drive each servo motor through the control signal to drive the six joint axes to move. This patent arranges the visual positioning system in the center of the movable chassis of the six-axis robot. The visual positioning system is mainly composed of an acquisition card, a visual camera, a switching module, etc. The function of the visual positioning system is to identify the QR code on the ground, use its visual imaging navigation system to locate and search, transmit movement instructions, mobilize the six-axis robot to move forward or backward, automatically find the workstation position, and automatically and accurately move to the workstation to grind the product.

[0010] (3) Support vehicle module: The support vehicle is used to support the product. The support vehicle module is mainly composed of a slider track, a rotating retaining ring, a drive motor and a lockable moving wheel. The slider track is placed on the lockable moving wheel. The lockable moving wheel can transfer and fix the support vehicle to a specified position under the action of the drive motor, so as to realize the transfer site of the grinding system; two rotating retaining rings are installed on the slider track, which can realize forward and backward movement and synchronous fixed-axis rotation, and can realize positioning locking, so as to move or fix the product to a specified position for grinding. The product is placed on the support vehicle and needs to be horizontally adjusted and axially positioned. For horizontal adjustment, the equipment used includes a laser distance sensor and a photoelectric sensor. Different products can use different types of sensors. This patent uses a laser distance sensor for horizontal adjustment. The laser distance sensor is installed at the rotating retaining ring on the support vehicle, collects measurement data and compares it with the preset value, so as to complete the horizontal posture adjustment. For axial positioning determination, a laser distance sensor is used on the sliding track of the support vehicle to measure the different positions of the rotating retaining rings corresponding to different products. The axial position of the rotating retaining ring is adjusted by comparing the measured value with the preset value of the product's three-dimensional digital model.

[0011] (4) Planning of grinding paths: By building a three-dimensional model of the product and importing it into the simulation software, the grinding process is simulated, and early warning and path planning are carried out for non-grinding or interference areas. The three-dimensional model is then imported into the robot's offline programming software, and the process parameters (mainly the grinding head moving speed, grinding trajectory) determined after the test are input as boundary conditions, and the software automatically generates a grinding program. The teach pendant is used to make adjustments based on the characteristics of each product and the differences between the actual product and the theoretical model, thereby completing the planning and programming of the entire grinding path.

[0012] (5) Grinding procedure: When the product is fixed on the rotating clamp on the support vehicle, select the corresponding product type in the program of the robot control cabinet. The rotating clamp on the support vehicle moves to the specified position according to the input signal and locks it, and then adjusts the posture of the product. The robot starts, automatically assembles the grinding head and moves to the corresponding station, and performs the grinding task according to the grinding program. When the grinding program of all stations of the product is completed, the robot returns to the initial position by scanning the preset QR code on the ground. The product rotates 180° driven by the two rotating clamps, and the robot repeats the grinding program until the product is polished. Set the grinding head replacement frequency according to the actual situation to ensure the grinding quality.

[0013] (III) Beneficial effects

[0014] The manufacturing method for the automated grinding system for complex and irregular thin-walled skins provided by the above technical solution adds the concept of intelligent processing design, and integrates force control, vision, software and other technologies in the grinding equipment, including automated robot technology, automatic grinding alignment planning technology, automatic camera positioning technology, etc., to achieve automated grinding of thin-walled skins of aviation products. The grinding head device uses multi-point sensing, positional force control, and comprehensive adjustment to highly integrate the sensing, control and execution systems. During the grinding process, the posture force / position mixed control compensation is performed according to the contact force between the end of the grinding head and the contact part of the product to ensure the accuracy and stability of the contact force of each grinding head. At the same time, it can also perform adaptive expansion and contraction according to the contour characteristics of the product surface to solve the problem of rapid movement between the grinding head and the contact surface, and the grinding head can be quickly replaced through the positioning buckle design. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the floating spindle and grinding head in the grinding head module.

[0016] Figure 2 Schematic diagram of a six-axis robot.

[0017] Figure 3 Schematic diagram of the support vehicle module.

[0018] As shown in the figure: circular grinding disc 1, force control integrated actuator 2, radial floating spindle 3, follower ball 4, grinding head 5, grinding head rod 6, control cabinet 7, teaching pendant 8, robot body 9, joint shaft 10, robot movable chassis 11, slider track 12, rotating clamping ring 13, driving motor 14, lockable moving wheel 15, first laser distance sensor 16, second laser distance sensor 17. DETAILED DESCRIPTION

[0019] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0020] This patent designs a grinding head module based on the characteristics of aviation products, such as many heterogeneous surfaces and difficult-to-grind materials. The grinding head module integrates seven independent radial floating spindles, each of which automatically adjusts the extension and posture of the grinding head according to its own contact force. This patent sets the contact force between the grinding head and the product surface to be constant at 30N, and the automatic extension distance is 100mm. The grinding heads are neatly arranged on the circular grinding disc, which can realize the rapid replacement of the grinding heads. The grinding path is planned according to the product appearance, and the automatic operation of the six-axis robot is coordinated to realize the automatic grinding of the product.

[0021] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] (1) Design of grinding head module: The grinding head module mainly consists of Figure 1 The seven independent radial floating spindles 3 and the force control integrated actuator 2 shown are composed, and the seven independent radial floating spindles 3 are arranged to form a circular grinding disc 1. Each radial floating spindle 3 contains a driving motor and a frequency converter. The force sensor at the top of each radial floating spindle 3 realizes high-precision force control adjustment. The front end of each force sensor transmits contact pressure through the follower ball 4. The structural shape of the force sensor at the top of the radial floating spindle 3 is similar to the head of a cylindrical pen core. Each radial floating spindle 3 is provided with a detachable grinding head 5. The grinding head 5 is similar to a screw-shaped cylinder with a rod. The rod 6 of the grinding head is assembled with the radial floating spindle 3 by means of sleeve insertion. After the grinding head 5 and the radial floating spindle 3 are assembled in place, they are positioned and locked by means of a snap-on method. The snap-on method can be quickly opened and installed after being pressed, so that the grinding head 5 can be replaced conveniently during the grinding process.

[0023] The force control integrated actuator 2 controls the rotation, attitude adjustment, motion state and telescopic stroke of each radial floating spindle 3. The force control integrated actuator 2 mainly includes attitude sensors, position sensors, acceleration sensors, force sensors and control systems. When the attitude sensor contacts and moves with the grinding head 5 and the workpiece surface, first, the force sensor of each grinding head 5 senses the contact pressure and determines the contact force between the grinding head 5 and the workpiece; the attitude sensor detects the position of the equipment; the position sensor detects the stroke position of the grinding head; the acceleration sensor determines the motion state of the grinding head; the control system collects the information fed back by each sensor, outputs the control signal through the force control algorithm, and the control signal electronic module regulator controls the rotation, attitude, telescopic stroke, etc. of each grinding head 5 to achieve grinding of the workpiece.

[0024] (2) Six-axis robot layout: Figure 1 The grinding head module shown is installed in Figure 2 The six-axis robot shown in FIG. 1 is a mature product on the market. Figure 1 The grinding head system shown can rotate in multiple directions and angles on the head of the six-axis robot. The six-axis robot is composed of a control cabinet 7, a teach pendant 8, and a robot body 9, wherein the control cabinet 7 is used to control the movement and posture of the robot; the teach pendant 8 is used to execute operating procedures and parameter configurations related to the operation and the robot; the robot body 9 is mainly composed of six joint axes 10, and each servo motor is driven by a control signal to drive the six joint axes 10 to move. The present invention arranges a visual positioning system at the center of the movable chassis 11 of the six-axis robot. The visual positioning system is mainly composed of an acquisition card, a visual camera, a switching module, etc. The function of the visual positioning system is to identify the QR code on the ground, use its visual imaging navigation system to perform positioning search, transmit movement instructions, and mobilize Figure 2 The six-axis robot shown moves forward or backward, automatically searches for the workstation position, and automatically and accurately moves to the workstation to polish the product.

[0025] (3) Support vehicle module: Figure 3 The support vehicle shown is used to support aviation products. The support vehicle module is mainly composed of a slider track 12, a rotating clamp 13, a drive motor 14 and a lockable moving wheel 15. The slider track 12 is placed on the lockable moving wheel 15, and the lockable moving wheel 15 can be moved and fixed under the action of the drive motor 14. Figure 3 The support vehicle shown in the figure is moved to the designated location to realize the transfer of the grinding system to the site; two rotating clamps 13 are installed on the slider track 12, which can realize forward and backward movement and synchronous fixed-axis rotation, and can realize positioning locking, so that the product can be moved or fixed at the designated location for grinding. Figure 3 The support vehicle shown needs to be adjusted horizontally and the axial positioning is determined. For the horizontal adjustment, the equipment used includes a laser distance sensor and a photoelectric sensor. Different products can use different types of sensors. This patent uses a first laser distance sensor 16 for horizontal adjustment. The first laser distance sensor 16 is installed at the rotating clamp 13 on the support vehicle to collect measurement data and compare it with the preset value to complete the horizontal posture adjustment. For the axial positioning, a second laser distance sensor 17 is used on the sliding track 12 of the support vehicle to measure the different positions of the rotating clamp 13 corresponding to different products. By comparing the measured value with the preset value of the product three-dimensional model, the axial position of the rotating clamp is adjusted.

[0026] (4) Planning of grinding path: By building a 3D model of the product and importing it into the simulation software, the grinding process can be simulated, and early warning and path planning can be performed for non-grinding or interference areas. Then the 3D model can be imported into the simulation software. Figure 2 In the offline programming software of the robot shown, the process parameters (mainly the grinding head moving speed and grinding trajectory) determined after the test are input as boundary conditions, and the grinding program is automatically generated by the software. According to the characteristics of each product and the difference between the actual product and the theoretical model, the teaching pendant 8 makes adjustments to complete the planning and programming of the entire grinding path.

[0027] (5) Polishing process: When the product is fixed on Figure 3On the rotating clamp ring 13 on the support vehicle shown, select the corresponding product type in the program of the robot control cabinet. The rotating clamp ring 13 on the support vehicle moves to the specified position according to the input signal and locks it, and then adjusts the posture of the product. The robot starts, automatically assembles the grinding head 5, and then moves to the corresponding station to perform the grinding task according to the grinding program. When the grinding program of all stations of the product is completed, the robot returns to the initial position by scanning the preset QR code on the ground. The product rotates 180° driven by the two rotating clamp rings 13. The robot repeats the grinding program until the product is polished. The replacement frequency of the grinding head 5 is set according to the actual situation to ensure the grinding quality. When the grinding head 5 is replaced, the robot returns to the initial position, and the joint shaft 10 is placed in the grinding head replacement box. After positioning, the grinding head 5 is detached and replaced by pressing.

[0028] It can be seen from the above technical solution that the present invention has the following significant features:

[0029] (1) The grinding head module is designed with seven independent force-controlled spindles, which can better adapt to the complex surfaces of aviation products. The grinding processes do not affect each other, and the grinding efficiency is high.

[0030] (2) The grinding heads are arranged neatly in a disc shape and placed in a grinding head replacement cabinet. The grinding heads and radial floating spindles are assembled through inserting buckles, and the grinding heads can be quickly replaced by automatically pressing with the robot joint arm.

[0031] (3) By combining the grinding head module and the robot and planning the automatic operation of the robot and the grinding head, the automated grinding of aviation products is realized, the manual grinding operation is eliminated, the grinding contact force is constant, and the grinding quality is guaranteed.

[0032] (4) The support vehicle module, grinding head module and robot system are all movable, which is convenient for subsequent site change and rearrangement, and the grinding production line is replicable.

[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A manufacturing method for an automated grinding system for complex and irregular thin-walled skins, characterized in that: The following steps are involved: (1) Design the grinding head module; (2) Layout of six-axis robot; (3) Design the support vehicle module; (4) Plan the polishing path; (5) Start the grinding process.

2. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skins according to claim 1, characterized in that: In step (1), the grinding head module includes seven independent radial floating spindles and a force control integrated actuator. The seven independent radial floating spindles are arranged to form a circular grinding disk, with one radial floating spindle located in the center and six radial floating spindles evenly distributed in the circumference. Each radial floating spindle contains a drive motor and a frequency converter. The force sensor at the top of each radial floating spindle realizes force control adjustment. The front end of each force sensor transmits contact pressure through a follower ball. Each radial floating spindle is equipped with a detachable grinding head. The grinding head is a cylinder with a rod. The rod of the grinding head is assembled with the radial floating spindle by means of sleeve insertion. After the grinding head and the radial floating spindle are assembled in place, they are positioned and locked by means of a snap-on method. The snap-on method can be quickly opened after being pressed, and the grinding head can be replaced during the grinding process. The force control integrated actuator controls the rotation, posture adjustment, motion state and telescopic stroke of each radial floating spindle.

3. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skins according to claim 2, characterized in that: In step (1), the force control integrated actuator includes a posture sensor, a position sensor, an acceleration sensor, a force sensor and a control system; When the attitude sensor moves in contact with the surface of the grinding head and the workpiece, the force sensor of each grinding head determines the contact force between the grinding head and the workpiece through contact pressure sensing; The posture sensor detects the position and posture of the device; The position sensor detects the travel position of the grinding head; the acceleration sensor determines the movement state of the grinding head; the control system collects the information fed back by each sensor and outputs a control signal. The control signal electronic module regulator controls the rotation, posture, telescopic travel of each grinding head to grind the workpiece.

4. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skins according to claim 3 is characterized in that: In step (2), the grinding head module is installed on the six-axis robot, and the grinding head module realizes multi-directional and multi-angle rotation on the head of the six-axis robot; the six-axis robot includes a control cabinet, a teach pendant, and a robot body, the control cabinet is used to control the movement and posture of the robot; the teach pendant is used to execute operation programs and parameter configurations related to the operation and the robot; the robot body includes six joint axes, and each servo motor is driven by a control signal to drive the six joint axes to move.

5. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skins according to claim 4, characterized in that: In step (2), a visual positioning system is arranged at the center of the movable chassis of the six-axis robot. The visual positioning system is used to identify the QR code on the ground, perform positioning search, transmit movement instructions, mobilize the six-axis robot to move forward or backward, automatically find the work station position, and automatically move to the work station to polish the product.

6. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skins according to claim 5, characterized in that: In step (3), the support vehicle module is used to support the product. The support vehicle module includes a slider track, a rotating clamp, a driving motor and a lockable movable wheel. The slider track is placed on the lockable movable wheel. The lockable movable wheel transfers and fixes the support vehicle to a specified position under the action of the driving motor, thereby realizing the transfer site of the grinding system. Two rotating clamps are installed on the slider track to realize forward and backward movement and synchronous fixed-axis rotation, and to achieve positioning locking, so that the product can be moved or fixed at a specified position for grinding.

7. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skins according to claim 6, characterized in that: In step (3), the product is placed on the support vehicle module for horizontal posture adjustment and axial positioning. A laser distance sensor is arranged on the support vehicle module for horizontal posture adjustment. The laser distance sensor is installed at the rotating clamp ring of the support vehicle module to collect measurement data for comparison with the preset value, thereby completing the horizontal posture adjustment.

8. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skin according to claim 7, characterized in that: In step (3), a laser distance sensor is used on the sliding track of the support vehicle module to measure the different positions of the rotating retaining rings corresponding to different products. The axial position of the rotating retaining ring is adjusted by comparing the measured values ​​with the preset values ​​of the product's three-dimensional digital model.

9. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skins according to claim 8, characterized in that: In step (4), a three-dimensional model of the product is established and imported into the simulation software to simulate the polishing process, and early warning and path planning are performed for non-polishing or interference areas. The three-dimensional model is then imported into the robot's offline programming software, and the determined process parameters are input as boundary conditions, and the software automatically generates a polishing program.

10. The manufacturing method for the automatic grinding system for complex and irregular thin-walled skin according to claim 9, characterized in that: In step (5), when the product is fixed on the rotating clamp on the support vehicle, the corresponding product type is selected in the program of the robot control cabinet, and the rotating clamp on the support vehicle moves to the specified position and locks it according to the input signal, and then the posture of the product is adjusted; the robot starts, automatically assembles the grinding head and moves to the corresponding station, and performs the grinding task according to the grinding program. When the grinding program of all stations of the product is completed, the robot returns to the initial position by scanning the preset QR code on the ground. The product rotates 180° driven by the two rotating clamps, and the robot repeats the grinding program until the product is polished.

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