A manufacturing method for an automated grinding system for complex, irregularly shaped, thin-walled skins

Abstract

This invention discloses a manufacturing method for an automated grinding system for complex, irregularly shaped thin-walled skin, comprising the following steps: (1) designing a grinding head module; (2) deploying a six-axis robot; (3) designing a support vehicle module; (4) planning the grinding path; and (5) starting the grinding process. This invention incorporates intelligent processing design concepts, integrating force control, vision, and software technologies into the grinding equipment. Specifically, it includes automated robot technology, automatic grinding alignment planning technology, and automatic photo positioning technology, achieving automated grinding of thin-walled skin for aerospace products. During the grinding process, attitude force / position hybrid control compensation is performed based on the contact force between the end of the grinding head and the contact area of ​​the product, ensuring the accuracy and stability of the contact force of each grinding head. Simultaneously, it can adaptively extend and retract according to the contour features of the product surface, solving the problem of rapid movement between the grinding head and the contact surface. Furthermore, the grinding head is quickly replaced through a positioning buckle design.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surface polishing treatment of titanium alloy, high-temperature alloy, resin-based composite and other special-shaped thin-walled shells, and relates to a manufacturing method of an automatic polishing system for complex special-shaped thin-walled skins. BACKGROUND

[0002] With the continuous innovation of aviation products, the structure and shape of the products are becoming more and more complex, and the material properties used for the outer skin are gradually developing in the direction of high hardness, high modulus and multi-function, among which titanium alloy, high-temperature alloy and composite material are typical representatives of the materials used for aviation products. In addition, the product structure design is complex, and the construction of each process is frequently crossed. If the surface treatment mode such as pickling and sandblasting is adopted, it is not very realistic. Laser cleaning is easy to cause damage to the installed electronic devices inside the product due to too high instantaneous temperature. Therefore, the current production mode of surface treatment in the workshop is still polishing. Manual polishing is difficult due to high working intensity, and the polishing quality is controlled entirely by the experience of the operators. Automatic polishing is difficult to be truly applied because the polishing head is difficult to adapt to the complex skin structure, and therefore the surface treatment mode of the skin seriously restricts the batch production of aviation products. SUMMARY

[0003] (I) Invention purpose

[0004] The purpose of the application is to provide a manufacturing method of an automatic polishing system for complex special-shaped thin-walled skins, to realize automatic polishing of complex special-shaped thin-walled skins of aviation products, to improve polishing efficiency, to solve the problem of low yield of manual polishing, and to meet the flexible polishing requirements of special structures and materials of aviation products.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the application provides a manufacturing method of an automatic polishing system for complex special-shaped thin-walled skins, which comprises the following steps:

[0007] (1) Design of polishing head module: the polishing 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 polishing disc. Each radial floating spindle contains a driving motor and a frequency converter. Each force sensor at the top end of the radial floating spindle realizes high-precision force control adjustment. Each force sensor at the front end transmits contact pressure through a follow-up ball. The structure of the force sensor at the top end of the radial floating spindle is similar to the head of a cylindrical pencil refill. Each radial floating spindle is provided with a detachable grinding head. The grinding head is similar to a screw-shaped rod cylindrical body. 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 buckling. The buckle can be quickly opened and disassembled after being pressed, facilitating the replacement of the grinding head during the polishing process.

[0008] The force control integrated actuator controls the rotation, posture adjustment, motion state and telescopic stroke of each radial floating spindle. The force control integrated actuator mainly includes a posture sensor, a position sensor, an acceleration sensor, a force sensor and a control system. When the grinding head and the workpiece surface are in contact, the force sensor of each grinding head first senses the contact force between the grinding head and the workpiece through the contact pressure; the posture sensor detects the position and posture of the equipment; the position sensor detects the stroke position of the grinding head; the acceleration sensor judges the motion state of the grinding head; the control system collects the information fed back by each sensor, outputs a control signal through a force control algorithm, and controls the rotation, posture and telescopic stroke of each grinding head through an electronic module regulator, so as to realize the 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 the present patent is a mature product on the market, and the grinding head system can realize multi-directional and multi-angle rotation on the head of the six-axis robot. The six-axis robot is composed of a control cabinet, a teach pendant and a robot body. The control cabinet is used to control the motion and posture of the robot; the teach pendant is used to execute operation programs and parameter configurations related to the robot; and the robot body is mainly composed of six joint axes, which are driven by servo motors to move. The present patent arranges a visual positioning system in the center of the movable chassis of the six-axis robot. The visual positioning system is mainly composed of a capture card, a visual camera and a switching module. The function of the visual positioning system is to identify a two-dimensional code on the ground, use the visual imaging navigation system to search and position, transmit a moving instruction, and mobilize the six-axis robot to move forward or backward to automatically find the work position and accurately move to the work position to grind the product.

[0010] (3) Support car module: the support car is used to support the product, and the support car module mainly consists of a sliding block track, a rotating clasp, a driving motor and a lockable mobile wheel. The sliding block track is arranged on the lockable mobile wheel, the lockable mobile wheel can shift and fix the support car to a specified position under the action of the driving motor, and the polishing system can be shifted to a site; two rotating clasps are installed on the sliding block track, 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 to a specified position for polishing. The product placed on the support car 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. The laser distance sensor is used for horizontal adjustment in this patent. The laser distance sensor is installed at the rotating clasp on the support car, and the measured data is compared with the preset value to complete the horizontal attitude adjustment. For axial positioning, a laser distance sensor is used on the sliding track of the support car to measure the different positions of the rotating clasp corresponding to different products. By comparing the measured value with the preset value of the three-dimensional model of the product, the axial position of the rotating clasp is adjusted.

[0011] (4) Planning of polishing path: by establishing a three-dimensional model of the product, the model is imported into the simulation software to simulate the polishing process, and the non-polishing or interference area is warned and path planned in advance. Then, the three-dimensional model is imported into the offline programming software of the robot, and the process parameters (mainly polishing head moving speed and polishing trajectory) determined after the test are input as boundary conditions to generate a polishing program automatically. According to the characteristics of each product and the difference between the physical product and the theoretical model, the teach pendant is used for adjustment, so as to complete the planning and programming of the entire polishing path.

[0012] (5) Polishing work program: when the product is fixed on the rotating clasp of the support car, the corresponding product type is selected in the program of the robot control cabinet, the rotating clasp on the support car moves to the specified position and is locked according to the input signal, and then the product is adjusted. After the robot starts, the polishing head is automatically assembled and moves to the corresponding station to execute the polishing program. When all the station polishing programs of the product are executed, the robot returns to the initial position by scanning the preset two-dimensional code on the ground, the product is rotated 180° under the driving of the two rotating clasps, and the robot repeats the polishing program until the product polishing is completed. The polishing head replacement frequency is set according to the actual situation to ensure the polishing quality.

[0013] (Three) Beneficial effects

[0014] The manufacturing method of the automatic polishing system for complex special-shaped thin-wall skin increases the intelligent processing design concept, and integrates force control, vision, software and other technologies in the polishing equipment, specifically including automatic robot technology, polishing automatic alignment planning technology, automatic photographing positioning technology and the like, and realizes the automatic polishing of the thin-wall skin of an aviation product. The polishing head device adopts multi-point sensing, sub-position force control, comprehensive adjustment and the like, highly integrates the sensing, control and execution systems, performs posture force / position hybrid control compensation according to the contact force of the grinding head end and the product contact position in the polishing process, ensures the accuracy and stability of the contact force of each grinding head, and can also be self-adapted according to the contour characteristics of the product surface, solves the rapid movement between the grinding head and the contact surface, and the grinding head realizes rapid replacement through the positioning buckle design. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Schematic diagram of a floating main shaft and a grinding head in a polishing head module.

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

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

[0018] The numbers in the figure represent: a circular polishing disc 1, a force control integrated actuator 2, a radial floating main shaft 3, a follow-up ball 4, a grinding head 5, a rod of the grinding head 6, a control cabinet 7, a teach pendant 8, a robot body 9, a joint shaft 10, a movable chassis 11 of the robot, a sliding block rail 12, a rotating clasp 13, a driving motor 14, a lockable movable wheel 15, a first laser distance sensor 16, and a second laser distance sensor 17. DETAILED DESCRIPTION

[0019] In order to make the purpose, content and advantages of the present application clearer, the specific embodiments of the present application are described in further detail below in combination with the drawings and examples.

[0020] The patent designs a polishing head module according to the characteristics of the aviation product, such as many special-shaped surfaces and difficult-to-polish materials. The polishing head module integrates seven independent radial floating main shafts. Each radial floating main shaft automatically adjusts the extension and posture of the grinding head according to the contact force of each grinding head. The patent sets the contact force between the grinding head and the product surface to be constant at 30N, the automatic extension distance is 100mm, the grinding heads are regularly arranged on the circular polishing disc, and the rapid replacement of the grinding heads can be realized. The polishing path is planned according to the product shape, and the six-axis robot is automatically operated to realize the automatic polishing of the product.

[0021] The present application is described in detail below in combination with the drawings and specific examples.

[0022] (1) Design of the polishing head module: the polishing head module mainly includes a polishing disc 1, a force control integrated actuator 2, a radial floating main shaft 3, a follow-up ball 4, a grinding head 5, a rod of the grinding head 6, a control cabinet 7, a teach pendant 8, a robot body 9, a joint shaft 10, a movable chassis 11 of the robot, a sliding block rail 12, a rotating clasp 13, a driving motor 14, a lockable movable wheel 15, a first laser distance sensor 16 and a second laser distance sensor 17.Figure 1 The seven independent radial floating main shafts 3 and the force control integrated actuator 2 constitute a circular polishing disc 1, each radial floating main shaft 3 contains a driving motor and a frequency converter, and the force sensor at the top end of each radial floating main shaft 3 realizes high-precision force control adjustment, the front end of each force sensor is in contact with the contact pressure through a follow-up ball 4, the structure of the force sensor at the top end of the radial floating main shaft 3 is similar to the head of a cylindrical pencil, each radial floating main shaft 3 is provided with a detachable grinding head 5, the grinding head 5 is a screw-like rod cylindrical body, the rod 6 of the grinding head 5 is assembled with the radial floating main shaft 3 in a sleeved manner, and the grinding head 5 and the radial floating main shaft 3 are positioned and locked through buckling after assembly, and the buckling can realize quick opening and disassembly after pressing, thereby facilitating the replacement of the grinding head 5 during polishing.

[0023] The force control integrated actuator 2 controls the rotation, posture adjustment, motion state and telescopic stroke of each radial floating main shaft 3, and mainly includes a posture sensor, a position sensor, an acceleration sensor, a force sensor and a control system. When the grinding head 5 and the workpiece surface are in contact motion, the force sensor of each grinding head 5 first senses and judges the contact force between the grinding head 5 and the workpiece through the contact pressure; the posture sensor detects the position and posture of the equipment; the position sensor detects the stroke position of the polishing head; the acceleration sensor judges the motion state of the grinding head; the control system collects the information fed back by each sensor, outputs a control signal through a force control algorithm, and controls the rotation, posture and telescopic stroke of each grinding head 5 through a control signal electronic module regulator, so as to realize polishing of the workpiece.

[0024] (2) Six-axis robot layout: as shown in Figure 1 The polishing head module is installed on the six-axis robot as shown in Figure 2 The six-axis robot used in the present patent is a mature product on the market, as shown in Figure 1 The polishing head system can rotate in multiple directions and at multiple 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 motion and posture of the robot; the teach pendant 8 is used to execute the running program, parameter configuration and the like related to the operation and the robot; and the robot body 9 is mainly composed of six joint axes 10, which are driven to move by control signals driving the servo motors. The present application arranges a visual positioning system in the center of the movable chassis 11 of the six-axis robot, which is mainly composed of a capture card, a visual camera and a switching module. The function of the visual positioning system is to identify the two-dimensional code on the ground, use the visual imaging navigation system to search and position, transmit the movement instructions, and mobilize the six-axis robot as shown in Figure 2 to move forward or backward to automatically find the work position and automatically and accurately move to the work position to polish the product.

[0025] (3) Support car module: the support car shown in Figure 3 is used to support the aerospace product. The support car module mainly consists of a sliding track 12, a rotating clasp 13, a driving motor 14, and a lockable mobile wheel 15. The sliding track 12 is placed on the lockable mobile wheel 15, which can be shifted and fixed under the action of the driving motor 14. Figure 3 The support car to the designated position, which can realize the transfer of the polishing system field; two rotating clamps 13 are installed on the sliding track 12, which can realize forward and backward movement and synchronous axis rotation, and can realize positioning locking, which can move or fix the product at the designated position for polishing. The product is placed on the support car shown in Figure 3 , which 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. The first laser distance sensor 16 is used for horizontal adjustment in this patent. The first laser distance sensor 16 is installed at the rotating clasp 13 on the support car, and the measured data is compared with the preset value to complete the horizontal attitude adjustment. For axial positioning, the second laser distance sensor 17 is used on the sliding track 12 of the support car to measure the different positions of the rotating clasp 13 corresponding to different products. By comparing the measured value with the preset value of the three-dimensional model of the product, the axial position of the rotating clasp is adjusted.

[0026] (4) Polishing path planning: by establishing a three-dimensional model of the product, importing it into the simulation software, and simulating the polishing process, early warning and path planning are performed for non-polishing or interference areas. Then, using the three-dimensional model, import it into the offline programming software of the robot shown in Figure 2 , input the process parameters determined after the test (mainly the polishing head moving speed and polishing trajectory) as boundary conditions, and generate the polishing program automatically by the software. According to the characteristics of each product, the difference between the physical product and the theoretical model, and the adjustment by the teach pendant 8, the entire polishing path planning and program compilation are completed.

[0027] (5) Polishing work program: when the product is fixed on the support car shown in Figure 3The rotation clasp 13 on the support car is shown on the machine control cabinet program, the corresponding product type is selected, the rotation clasp 13 on the support car moves to the specified position according to the input signal and is locked and fixed, and then the posture of the product is adjusted. The robot starts, moves to the corresponding station after automatically assembling the grinding head 5, performs the grinding task according to the grinding program, and when all the grinding programs of the product are completed, the robot returns to the initial position by scanning the pre-set two-dimensional code on the ground. The product is rotated 180° under the drive of the two rotation clamps 13, and the robot repeats the grinding program until the product grinding is completed. According to the actual situation, the grinding head 5 replacement frequency is set to ensure the grinding quality. When the grinding head 5 is replaced, the robot returns to the initial position, the joint shaft 10 is placed in the grinding head replacement box, and the grinding head 5 is separated and replaced by pressing after positioning.

[0028] From the above technical solution, the present application has the following remarkable features:

[0029] (1) The polishing head module is designed as seven independent force control spindles, which can better adapt to the complex surface of the aviation product, and the polishing process does not affect each other, and the polishing efficiency is high.

[0030] (2) The grinding head is regularly arranged in a disc shape and placed in the grinding head replacement cabinet. The grinding head and the radial floating spindle are assembled by a clamping buckle, and the grinding head can be quickly replaced by automatic pressing of the robot joint arm.

[0031] (3) By combining the polishing head module and the robot, the automatic operation of the robot and the polishing head is planned, the automatic polishing of the aviation product is realized, the manual polishing operation is removed, the polishing contact force is constant, and the polishing quality is guaranteed.

[0032] (4) The support car module, the polishing head module and the robot system can be moved, which is convenient for subsequent replacement of the site and rearrangement, and the polishing production line has replicability.

[0033] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, some improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should be regarded as the protection scope of the present application.

Claims

1. A method of manufacturing for an automated sanding system of complex contoured thin-skinned shells, characterized by, The method comprises the following steps: (1) designing a polishing head module; (2) arranging a six-axis robot; (3) designing a support vehicle module; (4) planning a polishing path; (5) starting a polishing work program; In step (1), the polishing head module comprises seven independent radial floating spindles and force control integrated actuators. The seven independent radial floating spindles are arranged to form a circular polishing disc. One radial floating spindle is located at the center, and six radial floating spindles are uniformly distributed in the circumferential direction. Each radial floating spindle contains a driving motor and a frequency converter. A force sensor at the top of each radial floating spindle realizes force control adjustment. Each force sensor at the front end transmits contact pressure through a follow-up ball. Each radial floating spindle is provided with a detachable grinding head. The grinding head is a rod cylinder. The rod of the grinding head is assembled with the radial floating spindle through a sleeve insertion mode. After the grinding head and the radial floating spindle are assembled in place, they are positioned and locked through a buckle mode. The buckle realizes quick opening and assembly after being pressed. The grinding head can be replaced during the polishing process. The force control integrated actuator controls the rotation, attitude adjustment, motion state and telescopic stroke of each radial floating spindle. In step (1), the force control integrated actuator comprises an attitude sensor, a position sensor, an acceleration sensor, a force sensor and a control system. The attitude sensor detects the position and attitude of the equipment when the grinding head and the workpiece surface are in contact. The position sensor detects the position of the polishing head. The acceleration sensor judges the motion state of the grinding head. The control system collects the information fed back by each sensor, outputs a control signal, and controls the rotation, attitude and telescopic stroke of each grinding head to polish the workpiece. In step (3), the support vehicle module is used to support the product. The support vehicle module comprises a sliding block track, a rotating clasp, a driving motor and a lockable moving wheel. The sliding block track is placed on the lockable moving wheel. The lockable moving wheel shifts and fixes the support vehicle to a specified position under the action of the driving motor, realizing the transfer of the polishing system to the site. Two rotating clasps are installed on the sliding block track to realize forward and backward movement and synchronous fixed-axis rotation, and to realize positioning and locking, so as to move or fix the product at a specified position for polishing. In step (3), the product is placed on the support vehicle module for horizontal attitude adjustment and axial positioning determination. A laser distance sensor is arranged on the support vehicle module for horizontal attitude adjustment. The laser distance sensor is installed at the rotating clasp of the support vehicle module. The measured data are compared with the preset values to complete the horizontal attitude adjustment. 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 clasp corresponding to different products. Through comparison of the measured values with the preset values of the three-dimensional model of the product, the axial position of the rotating clasp is adjusted. ​ 2. The manufacturing method for the automated sanding system of complex contoured thin-skinned shells of claim 1, wherein, In step (2), the polishing head module is installed on the six-axis robot, and the polishing head module rotates in multiple directions and at multiple angles 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 pose of the robot; the teach pendant is used to execute operation programs and parameter configurations related to 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.

3. The method of manufacturing for an automated sanding system of complex contoured thin-skinned shells of claim 2, wherein, In step (2), the six-axis robot has a movable chassis center layout vision positioning system, which is used to identify a two-dimensional code on the ground, search for a position, transmit a movement instruction, and mobilize the six-axis robot to move forward or backward to automatically find a work position and move to the work position to polish a product.

4. The method of manufacturing for an automated sanding system of complex contoured thin-skinned shells of claim 3, wherein, In step (4), a three-dimensional model of the product is established and imported into simulation software to simulate the polishing process, and a non-polishing or interference area is prewarned and path planned; then, the three-dimensional model is imported into robot offline programming software, the determined process parameters are input as boundary conditions, and a polishing program is automatically generated by the software.

5. The method of manufacturing for an automated sanding system of complex contoured thin-skinned shells of claim 4, wherein, In step (5), when the product is fixed on the rotating clasp on the support vehicle, the corresponding product type is selected in the program of the robot control cabinet, the rotating clasp on the support vehicle moves to the specified position and is locked and fixed according to the input signal, and then the product is adjusted in pose; the robot is started, moves to the corresponding station after being automatically assembled with the grinding head, and performs the polishing task according to the polishing program; when all the polishing programs of the product are executed, the robot returns to the initial position by scanning the preset two-dimensional code on the ground, the product is rotated by 180° under the driving of the two rotating clasps, the robot repeatedly executes the polishing program, and the polishing of the product is completed.

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