A grinding execution system for a water turbine blade

Abstract

The present invention discloses a grinding execution system for a water turbine blade, which includes a grinding execution mechanism module, a curved surface path planning module and a control module; the control module includes a host computer, a force sensor and a vibration sensor; the grinding execution mechanism module is connected to an industrial robot through the robot connection flange, and the force sensor is arranged between the robot connection flange and the grinding execution mechanism; the grinding execution mechanism module includes a grinding wheel machine mounting plate, a high-speed grinding wheel machine and an adjustable grinding wheel machine fixing rod, the vibration sensor is arranged on the grinding wheel machine mounting plate, and the connection between the grinding wheel machine mounting plate and the high-speed grinding wheel machine is connected by an extrusion fixing screw. The beneficial effects of the present invention are as follows: After the water turbine blade is ground by the grinding execution system of the industrial robot, the service life of the industrial robot can be increased and the grinding accuracy can be provided. The operation posture adjustment control of the industrial robot is convenient, the configuration is simple, and the economy is good.

Description

Technical Field

[0001] The present invention relates to the technical field of grinding execution equipment, and particularly relates to a grinding execution system for a water turbine blade. Background Art

[0002] The manufacturing technology of water turbine blades is the key to producing high-quality water turbines. Due to the complex shape structure and severe spatial distortion of water turbine blades, a high-efficiency grinding and processing execution system to meet the requirements of high-quality blades has become the key and core of the water turbine runner. At present, there is relatively little research on the industrial robot grinding execution system dedicated to water turbine blades at home and abroad, but its importance cannot be ignored. Especially in the grinding of hard materials such as stainless steel water turbine blades, because large grinding forces applied to the tool will cause vibration and instability, which will in turn affect the grinding accuracy and quality. At the same time, the surface of large water turbine blades after processing is a curved surface. Without precise curved surface path planning, the grinding efficiency and quality will be reduced. Therefore, it is extremely meaningful to invent a robot grinding system for large water turbine blades. Especially for large water turbine blades, after rough grinding by a gantry milling machine, the surface roughness is maintained at 32 - 50, and there are rough grinding marks on the blade surface. Subsequent fine grinding is required to make the surface roughness of the blade reach below 3.2μm and there are no obvious defects on the blade surface to meet the application requirements. At present, many enterprises mainly adopt the method of manual grinding, which has problems such as low processing efficiency and unstable processing quality. At the same time, a large amount of dust and iron filings will be generated during grinding, which may float in the air and be inhaled by the staff, thus posing a threat to physical health. Summary of the Invention

[0003] The purpose of the present invention is to provide a grinding execution system for a water turbine blade to solve the problems mentioned in the above background art.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A grinding execution system for a water turbine blade includes a grinding execution mechanism module, a curved surface path planning module, and a control module; the control module includes a host computer, a force sensor, and a vibration sensor; the grinding execution mechanism module is connected to an industrial robot through the robot connection flange, and the force sensor is arranged between the robot connection flange and the grinding execution mechanism; the grinding execution mechanism module includes a angle grinder mounting plate, a high-speed angle grinder, and an adjustable angle grinder fixing rod. The vibration sensor is arranged on the angle grinder mounting plate. The connection between the angle grinder mounting plate and the high-speed angle grinder is connected by an extrusion fixing screw. The adjustable angle grinder fixing rod is connected to the angle grinder mounting plate by a bolt, and the adjustable angle grinder fixing rod is connected to the high-speed angle grinder by an adjustable angle grinder fixing rod fixing bolt.

[0006] Furthermore, the robot connection flange adopts two industrial robot flange mounting plates, including a first industrial robot flange mounting plate and a second industrial robot flange mounting plate, and a rubber damping pad is provided between the first industrial robot flange mounting plate and the second industrial robot flange mounting plate.

[0007] Furthermore, the force sensor is bolted to the industrial robot flange mounting plate, and the force sensor is also bolted to the angle grinder mounting plate.

[0008] Furthermore, there are two extrusion fixing screws, including a first extrusion fixing screw and a second extrusion fixing screw. Rubber damping pads are provided at the bottoms of the two extrusion fixing screws to prevent the vibration generated during the grinding operation of the water turbine blade by the grinding execution system from damaging the shell of the high-speed angle grinder.

[0009] Furthermore, a U-shaped groove is provided at the top of the adjustable angle grinder fixing rod. Different types of high-speed angle grinders can be installed by adjusting through the U-shaped groove. A U-shaped protrusion is provided at the bottom of the angle grinder mounting plate, and the U-shaped protrusion is used to limit the positions of the adjustable angle grinder fixing rod and the bottom of the angle grinder mounting plate to ensure that these two components are on the same straight line.

[0010] Furthermore, vibration sensor mounting holes are provided on the angle grinder mounting plate, and vibration sensors are arranged in the vibration sensor mounting holes.

[0011] Furthermore, during the grinding operation, the force sensor will collect the force signals during the grinding process, and the force signals will be transmitted to the upper computer after being collected.

[0012] Furthermore, during the grinding operation, the vibration sensor will collect the vibration signals during the grinding process and transmit the vibration signals to the upper computer in real time. The upper computer will compare the vibration signals during the grinding process with the safe vibration frequency set by the system. If the frequency of the vibration signal exceeds the safe vibration frequency set by the system, at this time, the upper computer will transmit a signal to the force sensor to adjust the industrial robot and reduce the working grinding force to make the system operate normally. If the frequency of the vibration signal is lower than the safe vibration frequency set by the system, at this time, the upper computer will transmit a signal to the force sensor to adjust the industrial robot and increase the working grinding force.

[0013] Furthermore, the force sensor and the vibration sensor are respectively connected to the host computer through electrical signals. After the force sensor and the vibration sensor collect signals, they are transmitted to the host computer. The host computer processes the signals to obtain the displacement offset signal of the industrial robot. At the same time, an analog voltage signal is generated according to the displacement offset signal and transmitted to the industrial robot controller. The industrial robot controller receives the analog signal sent by the external device, adjusts the speed of the industrial robot or causes the robot to generate a displacement offset. The industrial robot controller collects the position information of the industrial robot and transmits it to the host computer. The host computer transmits the obtained displacement offset amount to the industrial robot, thereby realizing the stable operation of the grinding execution system.

[0014] Furthermore, the implementation steps of the curved surface path planning module are as follows: Import the three-dimensional model of the water turbine blade into the CAM module of the three-dimensional modeling software to generate U and V lines. Plan the curved surface path of the water turbine blade according to the planning goal to form a three-dimensional space curve. Extract the curved surface path generated in the CAM module, and discretize the curve of the curved surface path into spatial geometric points; Then, use the segmented circular arc interpolation method to optimize the generated curved surface path, perform inverse kinematics solution of the curved surface path after optimization, thereby removing the singular points of the curved surface path, perform pose correction of the curved surface path after removing the singular points, obtain the optimal operable curved surface path of the grinding execution system, and use the industrial robot conversion program to generate an industrial robot executable program from the obtained curved surface path.

[0015] The beneficial effects of the present invention: After the water turbine blade is ground by the grinding execution system of the industrial robot, the service life of the industrial robot can be improved and the grinding accuracy can be provided. The operation posture adjustment control of the industrial robot is convenient, the configuration is simple, and the economy is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0017] Figure 2 It is a schematic diagram of the overall structure of the grinding execution mechanism of the present invention;

[0018] Figure 3 It is an assembly schematic diagram of the adjustable angle grinder fixing rod and the angle grinder mounting plate of the present invention;

[0019] Figure 4 It is a schematic diagram of the overall structure of the grinding tool of the present invention;

[0020] Figure 5 It is a control flow chart of the offline programming system and the path program import module of the curved surface path planning module of the present invention;

[0021] In the figure: 1. Grinding actuator; 2. Industrial robot body; 3. Movable and convenient installation base for industrial robot; 11. First flange mounting plate of industrial robot; 12. Rubber damping pad; 13. Second flange mounting plate of industrial robot; 14. Vibration sensor; 15. First extrusion fixing screw; 16. Adjustable angle grinder fixing rod; 17. Fixing bolt for adjustable angle grinder fixing rod; 18. High-speed angle grinder; 19. Second extrusion fixing screw; 110. Angle grinder mounting plate; 111. Adjustable angle grinder fixing nut; 112. Force sensor. Specific embodiments

[0022] The present invention will be further described below in conjunction with the accompanying drawings of the specification.

[0023] Example:

[0024] As Figures 1-5 shown, a grinding execution system for a water turbine blade replaces the traditional manual grinding operation of the water turbine. The grinding execution system includes a grinding actuator module 1, a curved surface path planning module, a control module, an industrial robot body 2, and an industrial robot installation base 3.

[0025] The connection between the grinding actuator 1 and the industrial robot body 2 through the robot connection flange is connected by 4 M6x12 bolts; the industrial robot body 2 and the movable and convenient installation base 3 for the industrial robot are connected by 3 M6x110 double nuts to prevent loosening.

[0026] The grinding actuator system specifically consists of components such as the first flange mounting plate 11 of the industrial robot, the rubber damping pad 12, the second flange mounting plate 13 of the industrial robot, the vibration sensor 14, the first extrusion fixing screw 15, the adjustable angle grinder fixing rod 16, the fixing bolt 17 for the adjustable angle grinder fixing rod, the high-speed angle grinder 18, the second extrusion fixing screw 19, the angle grinder mounting plate 110, the adjustable angle grinder fixing nut 111, and the force sensor 112.

[0027] The robot connection flange mainly consists of two flange mounting plates of the industrial robot, including the first flange mounting plate 11 of the industrial robot and the second flange mounting plate 13 of the industrial robot; a rubber damping pad 12 is placed between the two flange mounting plates. The main function of the rubber damping pad 12 is to absorb the vibration generated when the grinding execution system grinds the water turbine blade, avoid damaging the industrial robot body, and at the same time ensure the stable connection between the industrial robot body and the grinding execution system.

[0028] The force sensor 111 is connected by 4 M6x12 bolts. The bottom of the force sensor 112 is connected to the angle grinder mounting plate 110 of the grinding execution system by M6x16 bolts. The angle grinder mounting plate 110 is provided with vibration sensor mounting holes, and the 14 vibration sensors can be adsorbed and installed.

[0029] The two adjustable angle grinder fixing rods 16 are connected to the angle grinder mounting plate 110 by two M6x12 bolts. The angle grinder mounting plate 110 is connected to the high-speed angle grinder 18 by two M6x12 bolts. At the connection between the top of the adjustable angle grinder fixing rod 16 and the bottom of the angle grinder mounting plate 110, a U-shaped groove and a U-shaped protrusion are respectively provided. The U-shaped groove can install different types of high-speed angle grinders by adjusting the adjustable angle grinder fixing rod 16. The function of the U-shaped protrusion is to limit the positions of the adjustable angle grinder fixing rod 16 and the bottom of the angle grinder mounting plate 110, ensuring that these two components are on the same straight line.

[0030] Both the bottoms of the two extrusion fixing screws, namely the first extrusion fixing screw 15 and the second extrusion fixing screw 19, are provided with rubber damping pads. The function of the rubber damping pads at the bottom is to prevent the vibration generated during the grinding operation of the water turbine blade by the grinding execution system from damaging the shell of the high-speed angle grinder 18. At the same time, these two extrusion fixing screws can adjust the level of the angle grinder mounting plate 110 to ensure the stability and connection reliability of the grinding execution mechanism.

[0031] The function of the force sensor is that when the grinding system is working, after the force signal is collected and transmitted to the upper computer, the upper computer is installed with data processing software adapted to the force sensor. The upper computer obtains the displacement offset signal of the industrial robot after processing the force sensor and the vibration sensor, and at the same time generates an analog voltage signal according to the displacement offset signal and transmits it to the robot controller, so as to realize the pose control of the industrial robot. The function of the vibration sensor is that when the grinding execution system of the water turbine blade is grinding, the vibration sensor will collect the vibration signal generated during the grinding process of the water turbine blade and transmit the vibration signal to the grinding execution system in real time. The grinding execution system will compare the vibration signal during the grinding process with the safe vibration frequency set by the system. If the frequency of the vibration signal exceeds the safe vibration frequency set by the system, this grinding execution system will adjust the pose of the industrial robot and reduce the working grinding force of the grinding execution system to make the system operate safely and stably. If the frequency of the vibration signal is lower than the safe vibration frequency set by the system, at this time the grinding execution system will adjust the pose of the industrial robot and increase the working grinding force of the grinding system.

[0032] A control module in the grinding system of a grinding execution system for water turbine blades mainly consists of Figure 1 the industrial robot 2 in Figure 2It consists of a force sensor 112, a vibration sensor 14 and an upper computer. After the force signal and the vibration signal are collected, they are transmitted to the upper computer. Data processing software adapted to the force sensor and the vibration sensor is installed in the upper computer. The upper computer obtains the displacement offset signal of the industrial robot after processing the force sensor and the vibration sensor, and at the same time generates an analog voltage signal according to the displacement offset signal and transmits it to the robot controller. The software built into the controller receives the analog signal sent by the external device and can adjust the speed of the industrial robot or cause the robot to have a displacement offset. The displacement offset and the speed adjustment are different interfaces respectively, and they do not interfere with each other. The speed of the robot can be reduced in equal proportion. The controller collects the position information of the industrial robot and transmits it to the upper computer, and the upper computer transmits the obtained displacement offset amount to the robot. Thus, the stable operation of the grinding execution system is realized.

[0033] A curved surface path planning module of a grinding execution system for a hydroturbine blade mainly consists of an offline programming system and a path program import module. Its working principle is as follows: The three-dimensional model of the hydroturbine blade is imported into the CAM module of the three-dimensional modeling software to generate U and V lines. The curved surface path of the hydroturbine blade is planned according to the planning target to form a three-dimensional space curve. The curved surface path generated in the CAM module is extracted, and the curve of the curved surface path is discretized into spatial geometric points. Then, the generated curved surface path is optimized by using the segmented circular arc interpolation method, and the inverse kinematics of the robot is performed on the optimized curved surface path, so that the singular points of the curved surface path can be removed. Removing the singular points can enable the grinding execution system to operate normally and stably. The pose correction of the curved surface path is performed on the curved surface path after removing the singular points to obtain the optimal operable curved surface path of the grinding execution system. The industrial robot conversion program is used to generate an executable program for the industrial robot from the obtained curved surface path. Finally, the executable program is uploaded to the industrial robot control cabinet, so that the curved surface path planning module of the grinding execution system operates stably and reliably. Using offline programming for curved surface path planning can greatly improve the efficiency and accuracy of the grinding execution system in grinding hydroturbine blades.

[0034] The curved surface path planning module is developed through secondary development using relevant 3D modeling software platforms and some auxiliary programming development tools. Although there are a small number of secondary developments based on SolidWorks or UG in China at present, a complete offline programming system and path program import function cannot be formed. It can only be used for the simulation of the curved surface path but cannot import the program into the industrial robot body, so it is not applicable to actual industrial production. The curved surface path planning based on curvature is carried out on a dedicated CAM software. Since the curvature distribution of the complex curved surface of the water turbine is irregular and the planning of the machining trajectory is affected by the curvature, relevant information of the 3D model of the water turbine must be extracted during the planning of the tool path, including the position information of the contact point between the tool and the curved surface, the curvature radius information of the contact point with the curved surface, etc. The machining trajectories of different types of blade curved surfaces are used for planning, and the planning of the curved surface machining trajectory is realized through the CAM module of the 3D modeling software. The intelligent planning of the blade machining trajectory based on different machining parameters can be realized, and the machining accuracy of the curved surface is guaranteed. This module is developed through secondary development using C++ based on the 3D modeling software, which can import the 3D model of the water turbine blade into the 3D modeling software, generate, extract, and export the actual curved surface path of the industrial robot offline. The posture obtained from the teaching points is interpolated and synthesized with the position information of the trajectory points. The grinding trajectory is converted to the robot base coordinate system, and a robot program is generated to complete the planning process.

Claims

1. A grinding execution system for a water turbine blade, characterized in that, it includes a grinding execution mechanism module, a curved surface path planning module and a control module; the control module includes a host computer, a force sensor and a vibration sensor; the grinding execution mechanism module is connected to an industrial robot through a robot connection flange, and the force sensor is arranged between the robot connection flange and the grinding execution mechanism; the grinding execution mechanism module includes a grinding machine mounting plate, a high-speed grinding machine and an adjustable grinding machine fixing rod, the vibration sensor is arranged on the grinding machine mounting plate, the connection between the grinding machine mounting plate and the high-speed grinding machine is connected by an extrusion fixing screw, the adjustable grinding machine fixing rod is connected to the grinding machine mounting plate by bolts, and the adjustable grinding machine fixing rod is connected to the high-speed grinding machine by an adjustable grinding machine fixing bolt; The robot connection flange uses two industrial robot flange mounting plates, including a first industrial robot flange mounting plate and a second industrial robot flange mounting plate, and a rubber damping pad is arranged between the first industrial robot flange mounting plate and the second industrial robot flange mounting plate; There are two extrusion fixing screws, including a first extrusion fixing screw and a second extrusion fixing screw, and rubber damping pads are arranged at the bottoms of the two extrusion fixing screws to prevent the vibration generated during the grinding operation of the water turbine blade by the grinding execution system from damaging the shell of the high-speed grinding machine; The top of the adjustable grinding machine fixing rod is provided with a U-shaped groove, and different types of high-speed grinding machines can be installed by adjusting through the U-shaped groove. The bottom of the grinding machine mounting plate is provided with a U-shaped protrusion, and the U-shaped protrusion is used for position limitation between the adjustable grinding machine fixing rod and the bottom of the grinding machine mounting plate to ensure that these two parts are on the same straight line.

2. The grinding execution system for a water turbine blade according to claim 1, characterized in that, the force sensor is connected to the industrial robot flange mounting plate by bolts, and the force sensor is connected to the grinding machine mounting plate by bolts.

3. The grinding execution system for a water turbine blade according to claim 1, characterized in that, a vibration sensor mounting hole is arranged on the grinding machine mounting plate, and the vibration sensor is arranged in the vibration sensor mounting hole.

4. The grinding execution system for a water turbine blade according to claim 1, characterized in that, during the grinding operation, the force sensor will collect the force signal during the grinding process, and the force signal is transmitted to the host computer after being collected.

5. The grinding execution system for a water turbine blade according to claim 4, characterized in that, During the grinding operation, the vibration sensor collects the vibration signals during the grinding process and transmits the vibration signals to the host computer in real time. The host computer compares the vibration signals during the grinding process with the safe vibration frequency set by the system. If the frequency of the vibration signal exceeds the safe vibration frequency set by the system, at this time, the host computer transmits a signal to the force sensor to adjust the industrial robot and reduce the working grinding force to make the system operate normally. If the frequency of the vibration signal is lower than the safe vibration frequency set by the system, at this time, the host computer transmits a signal to the force sensor to adjust the industrial robot and increase the working grinding force.

6. A grinding execution system for a hydraulic turbine blade according to claim 5, characterized in that, the force sensor and the vibration sensor are respectively electrically connected to the host computer. After the force sensor and the vibration sensor collect signals, they are transmitted to the host computer. After the host computer processes them, an industrial robot displacement offset signal is obtained. At the same time, an analog voltage signal is generated according to the displacement offset signal and transmitted to the industrial robot controller. The industrial robot controller receives the analog signal sent by the external device, adjusts the speed of the industrial robot or causes the robot to have a displacement offset. The industrial robot controller collects the position information of the industrial robot and transmits it to the host computer. The host computer transmits the obtained displacement offset amount to the industrial robot, thereby realizing the stable operation of the grinding execution system.

7. A grinding execution system for a hydraulic turbine blade according to claim 1, characterized in that, the implementation steps of the curved surface path planning module are as follows: Import the three-dimensional model of the hydraulic turbine blade into the CAM module of the three-dimensional modeling software to generate U and V lines. Plan the curved surface path of the hydraulic turbine blade according to the planning goal to form a three-dimensional space curve. Extract the curved surface path generated in the CAM module. Discretize the curve of the curved surface path into spatial geometric points; Then use the segmented circular arc interpolation method to optimize the generated curved surface path, perform inverse kinematics solution of the curved surface path after optimization, thereby removing the singular points of the curved surface path, perform pose correction of the curved surface path after removing the singular points, obtain the optimal operable curved surface path of the grinding execution system, and use the industrial robot conversion program to generate an industrial robot executable program from the obtained curved surface path.

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