Paint surface defect polishing device

Abstract

The invention discloses a paint surface defect polishing device. The grinding device comprises a base and a grinding assembly, three air cylinders are arranged on the base, and the air cylinders are perpendicular to the upper surface of the base; the three air cylinders are connected with the grinding assembly, and the grinding assembly comprises a fixing plate, a motor, a distance measuring sensor and a grinding tool. The six-dimensional force sensor is combined with the robot, and polishing posture adjustment and force control are conducted through a robot body. If a scene with a remarkable curved surface curvature change is encountered, all shafts of the robot need to cooperate to adjust the posture. According to the invention, the problem that a polishing tool carried by a robot in the prior art cannot adapt to polishing of a paint surface is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of body painting, and particularly to a paint defect grinding device. Background Art

[0002] In the related art, in the body production line, defects such as shrinkage holes and protrusions sometimes appear on the body paint surface. To solve the paint surface defects, manual grinding and polishing methods are often used. However, this requires workers to have rich grinding experience. Even so, it still takes a long time for grinding. To improve work efficiency, a detailed work strategy needs to be formulated, usually manifested as multiple people and multiple workstations collaborating to complete the defect correction process. To reduce the intensity of manual operations and improve the efficiency of the process flow, a robot - carried grinding tool has been invented, aiming to let the robot replace manual workers to carry tools to grind and polish the paint surface. However, the existing grinding tools are too dependent on the adjustment of the robot body posture to approach the defect position and adapt to the geometric changes of the paint surface. The process of the robot adjusting its posture greatly prolongs the overall process time and reduces the efficiency of the grinding work. Moreover, the paint surface of the body is mostly a three - dimensional structure rich in curved surfaces, inclined surfaces, etc. Only relying on adjusting the robot pose cannot fully adapt to grinding the paint surface. When facing high - intensity and high - beat production requirements, there will be situations where the robot pose is unreachable or the defect with too long grinding process time is abandoned. Currently, although some grinding tools have considered this problem in their development, they are all passive adaptation technologies for the paint surface (for example, CN111421444A, which changes the angle between the ball - head shaft and the grinding disc by squeezing the paint surface), and their adaptability to the paint surface is also poor.

[0003] Therefore, the technical problem that the grinding tools carried by robots in the related art cannot adapt to grinding the paint surface has not been effectively solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a paint defect grinding device to solve the problem that the grinding tools carried by robots in the related art cannot adapt to grinding the paint surface.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A paint defect grinding device includes a base and a grinding assembly. Three cylinders are arranged on the base, and the cylinders are perpendicular to the upper surface of the base; the three cylinders are respectively connected to the grinding assembly, and the grinding assembly includes a fixing plate, a motor, a ranging sensor, and a grinding tool.

[0007] Further, a frame fixing plate is arranged at the top of the cylinder. The frame fixing plate is parallel to the upper surface of the base, and a circular through - hole is arranged at the center of the frame fixing plate.

[0008] Further, a rotating pair is fixedly connected to the middle of the cylinder through a connecting block.

[0009] Further set as: A connecting rod is rotatably connected to the rotating pair.

[0010] Further set as: The connecting rod passes through the circular through-hole.

[0011] Further set as: The top of the connecting rod is connected to the bottom surface of the fixed plate through a Hooke hinge.

[0012] Further set as: A motor is fixedly connected to the fixed plate.

[0013] Further set as: Three distance sensors are fixedly connected to the fixed plate.

[0014] Further set as: A grinding tool is fixedly connected to the top of the motor.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are:

[0016] The paint surface defect grinding device has a series of remarkable technical effects. In terms of grinding accuracy, the cylinder can inversely solve the telescopic distance according to the constructed approximate plane equation, and autonomously adjust the optimal angle and grinding force of the grinding tool. After adjusting to the best angle, each cylinder extends forward synchronously to the preset grinding pressure, and maintains a constant pressure throughout the grinding process through the control valve group to ensure high-quality grinding. The structural design endows it with high flexibility. The fixed plate and the cylinder are connected by a Hooke hinge or a ball hinge, greatly improving the degree of freedom of the fixed plate. Cooperating with at least three cylinders and connecting rods, the angle between the grinding tool and the paint surface can be accurately and flexibly adjusted to meet the diverse grinding needs of different paint surfaces and defects. The distance sensor measures the distance from the paint surface in real time, providing key data support for angle adjustment. The device has excellent environmental adaptability. Using the pneumatic method, it can be safely applied to explosion-proof environments, broadening the usage scenarios. At the same time, the compressibility of the gas makes the pneumatic method have stronger force control anti-interference ability compared with the electric method, ensuring the stability of force output during the grinding process. From the overall structure, the parallel setting of the frame fixed plate and the base and the circular through-hole design, combined with the rotating pair connection in the middle of the cylinder, ensure the structural stability of the device and are conducive to accurate grinding. And the fixed plate integrally installs the distance sensor, the motor and the grinding tool, making the device structure compact and easy to operate and control. In summary, the grinding device provides an efficient and reliable solution for the repair of paint surface defects with accurate grinding, flexible adjustment, good adaptability and stable structure. Description of the Drawings

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 is the overall structural schematic diagram of the present invention;

[0019] Figure 2 is the front view of the present invention;

[0020] Figure 3 is the spatial structural schematic diagram of the painted surface to be polished;

[0021] Figure 4 is the overall structural schematic diagram of Structure 1;

[0022] Figure 5 is the front view of Structure 1;

[0023] Figure 6 is the overall structural schematic diagram of Structure 2;

[0024] Figure 7 is the front view of Structure 2;

[0025] Figure 8 is the overall structural schematic diagram of Structure 3;

[0026] Figure 9 is the front view of Structure 3.

[0027] Reference numerals: 1, base; 2, cylinder; 3, frame fixing plate; 4, rotating pair; 5, connecting rod; 6, fixing plate; 7, motor; 8, grinding tool; 9, distance measuring sensor; 10, Hooke's joint; 11, guide rail; 12, slider; 13, cylinder mounting seat. Detailed implementation manners

[0028] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Embodiment 1

[0032] Referring to Figure 1-2 , a paint surface defect grinding device disclosed in the present invention, the invention includes: a base 1 and a grinding assembly. Three cylinders 2 are provided on the base 1, and the cylinders 2 are perpendicular to the upper surface of the base 1; the three cylinders 2 are respectively connected to the grinding assembly, and the grinding assembly includes a fixing plate 6, a motor 7, a distance measuring sensor 9, and a grinding tool 8.

[0033] Specifically, after the workpiece paint surface is formed, there are often various defects, such as shrinkage holes, protrusions, dents, etc. In order to remove the paint surface defects, the paint surface defects need to be polished and buffed multiple times. The present invention is composed of a base 1, a fixing plate 6, a cylinder 2, a motor 7, a grinding tool 8, and a distance measuring sensor 9. The main function of the base 1 is to install the cylinder 2 and connect it to the six-axis flange of the robot, so that the robot holds the paint surface defect grinding device and autonomously goes to the defective paint surface for grinding.

[0034] The function of the grinding tool 8 is to grind and polish the paint surface. The grinding tools 8 corresponding to different defects are not the same. For example, wool wheels, sponge wheels, polishing agents, etc. The grinding tool 8 is installed at the front end of the motor 7. The main function of the motor 7 is to provide power for the grinding tool 8. The control system will control the rotation speed of the motor 7 according to the defect type to achieve the optimal grinding effect, and it is installed on the fixing plate 6. The main function of the frame fixing plate 3 is to reinforce the cylinder 2 and prevent the cylinder 2 from swinging due to lateral force. The main function of the connecting rod 5 is to connect the cylinder 2 and the fixing plate 6 to facilitate the adjustment of the fixing plate 6 by the cylinder 2.

[0035] The base 1 is connected to the six-axis flange of the robot, enabling the robot to hold the grinding device and autonomously move to the defective paint surface for grinding. This realizes automated operation, improves work efficiency, reduces manual intervention, lowers labor costs, and can more accurately locate the defective position. Different grinding tools 8 (such as wool wheels, sponge wheels, polishing agents, etc.) can be used for different defects, enabling the treatment of various paint surface defects such as shrinkage holes, protrusions, and dents, improving the grinding effect and quality, and enabling the paint surface to be more ideally repaired. The control system controls the rotation speed of the motor 7 according to the defect type to achieve the optimal grinding effect. This adjustable power output can better adapt to different grinding requirements, avoid secondary damage to the paint surface due to improper power, and further ensure the grinding quality. The frame fixing plate 3 can reinforce the cylinder 2, prevent the cylinder 2 from swinging due to lateral force, ensure the stability of the entire device during the grinding process, make the grinding operation more accurate and reliable, and is conducive to improving the grinding accuracy and effect. The connecting rod 5 connects the cylinder 2 and the fixing plate 6, facilitating the adjustment of the fixing plate 6 by the cylinder 2, enabling the position of the grinding assembly to be flexibly adjusted according to the actual grinding requirements, enhancing the adaptability and operability of the device, and being able to better handle paint surface defects at different positions and angles.

[0036] It is further set that: a frame fixing plate 3 is provided at the top of the cylinder 2. The frame fixing plate 3 is parallel to the upper surface of the base 1. A circular through hole is provided at the center of the frame fixing plate 3. A rotating pair 4 is fixedly connected to the middle of the cylinder 2 through a connecting block. A connecting rod 5 is rotatably connected to the rotating pair 4. The connecting rod 5 passes through the circular through hole. The top of the connecting rod 5 is connected to the bottom surface of the fixing plate 6 through a Hooke's joint 10. A motor 7 is fixedly connected to the fixing plate 6. Three ranging sensors 9 are fixedly connected to the fixing plate 6. A grinding tool 8 is fixedly connected to the top of the motor 7.

[0037] Specifically, the main function of the cylinder 2 is to control its own telescopic distance to adjust the optimal angle and grinding force of the grinding tool 8. The control system will inversely solve how much distance each cylinder 2 needs to extend or retract according to the constructed approximate plane equation to make the grinding tool 8 at the optimal grinding angle. The cylinder 2 is installed on the base 1. The cylinder 2 is connected to the frame fixing plate 3 by a connecting rod 5. The connecting end of the connecting rod 5 and the cylinder 2 is a rotating pair 4. The connecting end of the connecting rod 5 and the frame fixing plate 3 is a ball joint or a Hooke's joint 10. At least three cylinders 2 are required for more precise adjustment of the fixing plate 6.

[0038] The cylinder 2 can autonomously control the force and position parameters without relying on the feedback control of a mechanical sensor. When the cylinder 2 adjusts the polishing angle in real time, it will output a constant polishing pressure according to the defect type to ensure precise control of the polishing force. After the cylinder 2 is adjusted to the optimal polishing angle, each cylinder 2 will extend forward synchronously until the polishing tool 8 contacts the paint surface and reaches the preset polishing pressure. At this time, the motor 7 provides power for the polishing tool 8 to start polishing. During polishing, the control valve group will control the supply amount of compressed air of the cylinder 2 to achieve a constant polishing pressure during the polishing process.

[0039] Advantages of pneumatic compared to electric: It can be used in explosion-proof environments; the gas itself has certain compression properties and the coordinated control of multiple motors is difficult, so pneumatic has stronger force control anti-interference ability compared to electric.

[0040] Specifically, the main function of the fixing plate 6 is to install and fix the ranging sensor 9, the motor 7 and the polishing tool 8. The fixing plate 6 is connected to the cylinder 2 by a Hooke joint 10 or a ball joint, aiming to increase the degree of freedom of the fixing plate 6 to facilitate the adjustment of the angle between the polishing tool 8 and the paint surface. When polishing defects, the optimal polishing angle and polishing force between the polishing tool 8 and the paint surface are different for different types of defects.

[0041] The main function of the ranging sensor 9 is to measure the distance between it and the paint surface. Therefore, in order to adapt to different paint surfaces and different defects, it is necessary to continuously adjust the polishing angle between the polishing tool 8 and the paint surface. The polishing tool 8 is installed on the fixing plate 6, so the angle between the polishing tool 8 and the paint surface can be adjusted by adjusting the angle between the fixing plate 6 and the paint surface.

[0042] The cylinder 2 can inversely solve the telescopic distance according to the constructed approximate plane equation, autonomously control its own telescopic movement to adjust the optimal angle and polishing force of the polishing tool 8, and achieve precise polishing to cope with the different polishing angles and forces required for different types of defects.

[0043] After the cylinder 2 is adjusted to the optimal polishing angle, it extends forward synchronously until the preset polishing pressure is reached, and during the polishing process, the supply amount of compressed air is controlled by the control valve group to output a constant polishing pressure, ensuring the stability and precision of the polishing force and improving the polishing quality. The fixing plate 6 is connected to the cylinder 2 by a Hooke joint 10 or a ball joint, increasing the degree of freedom of the fixing plate 6 and facilitating the flexible adjustment of the angle between the polishing tool 8 and the paint surface to adapt to the polishing requirements of different paint surfaces and different defects. At least three cylinders 2 cooperate with structures such as the connecting rod 5 to enable more precise adjustment of the fixing plate 6, making the position and angle adjustment of the polishing tool 8 more flexible and precise.

[0044] The distance measuring sensor 9 can measure the distance between it and the paint surface, providing data support for adjusting the angle between the grinding tool 8 and the paint surface, so as to continuously adjust the grinding angle according to the actual situation and ensure the grinding effect. Using the pneumatic method, it has the advantage of being able to be used in explosion-proof environments, broadening the application scenarios of the device and being suitable for some special environments with high safety requirements. The compression property of the gas itself and the characteristic that it is more difficult to control multiple electric motors in coordination compared to electricity make the pneumatic have stronger force control anti-interference ability, and can better maintain the stable output of force during the grinding process, improving the reliability of grinding.

[0045] The frame fixing plate 3 is parallel to the base 1 and is provided with a circular through hole at the center and other structural designs, and the connection method such as fixing the rotating pair 4 through the connecting block in the middle of the cylinder 2 makes the entire device structure stable, ensuring the relative positions of each component during the grinding process are stable, which is beneficial to precise grinding. The fixing plate 6 can install and fix the distance measuring sensor 9, the motor 7 and the grinding tool 8, realizing the integration of functions, making the device structure compact and facilitating the overall operation and control.

[0046] Refer to Figure 3 , Figure 3 is a schematic diagram of the spatial structure of the paint surface to be ground. As can be seen from the figure, the three distance measuring sensors 9 on the fixing plate 6 can measure the straight-line distance between them and the paint surface. Therefore, according to the known coordinates of the distance measuring sensor 9 and the measured straight-line distance, using the principle of spatial coordinate transformation, the translation and rotation of spatial coordinates are used to determine the coordinates of each point in space. Obtain the spatial coordinates of points A, B, and C on the paint surface. Furthermore, the plane equation formed by the above three points can be obtained according to the coordinates of points A, B, and C. The above plane equation is the approximate plane equation of the defective paint surface, and the basic information of the paint surface (three-dimensional dimensions: radian, inclination angle, normal direction, etc.) can be inversely solved through the plane equation, and then the optimal grinding angle of the corresponding grinding tool 8 can be adjusted. The main function of the distance measuring sensor 9 is to measure and feedback the straight-line distance between it and the paint surface in real time, providing data support for adjusting the optimal grinding angle of the grinding tool 8.

[0047] Because the grinding tool 8 can adjust the grinding posture in real time according to the change of the paint surface during grinding, there is no need for the robot to adjust its posture to adapt to the change of the paint surface, which greatly reduces the frequent adjustment of the robot's posture and saves the grinding time.

[0048] The following lists several grinding working conditions:

[0049] Working condition 1: If the paint defect is very large, such as scratches, the robot will move while grinding to cover the entire defect. Working condition 2: If the paint defect is a large annular defect, the robot will draw a circle while grinding to achieve comprehensive grinding. Working condition 3: If the defect is small, the robot stays in place and grinds. Because the grinding device can adjust the angle of the grinding tool 8 in real time and continuously supply a constant grinding pressure, it has stronger adaptability to various complex grinding working conditions.

[0050] The control valve group can be installed on the grinding device or separately installed in other places. Its main function is to control the supply of compressed air, output and maintain a constant grinding pressure.

[0051] In addition, before the body paint grinding station is the body defect paint detection station. The function of this station is to judge the type and coordinates of the body paint defect and transmit them to the grinding station. After the grinding station control system obtains the defect coordinates, it will transmit the coordinates to the robot and independently plan the robot trajectory path to make the robot carry the grinding device and move above the paint defect; after the grinding station control system obtains the defect type, it will select the corresponding grinding tool 8 and grinding force according to the defect type (different defects require different grinding tools 8 and grinding forces, and some defects even need to be ground with different grinding tools 8 for several rounds).

[0052] Embodiment 2

[0053] Refer to Figure 4-5 , this structure uses the guide rail 11 instead of the rodless cylinder 2 as the telescopic mechanism. The lower end of the slider 12 of the guide rail 11 is the traditional cylinder 2 to provide power for the slider 12 to control its up and down movement. The guide rail 11 is fixedly connected between the base 1 and the frame fixing plate 3. The cylinder 2 can be installed at the bottom of the guide rail 11 as an integral structure or installed on the base 1. The piston rod of the cylinder 2 is connected to the slider 12 of the guide rail 11. The slider 12 of the guide rail 11 is connected to the fixing plate 6 by a connecting rod 5. There is a rotating pair 4 between the connecting rod 5 and the slider 12 of the guide rail 11, and a ball joint or Hooke joint 10 between the connecting rod 5 and the fixing plate 6.

[0054] Embodiment 3

[0055] Refer to Figure 6-7 , this structure's telescopic mechanism uses the traditional cylinder 2. The cylinder 2 is directly installed between the base 1 and the fixing plate 6. The cylinder 2 is connected to the base 1 by a rotating pair 4, and the piston rod of the cylinder 2 is connected to the fixing plate 6 by a ball joint or Hooke joint 10.

[0056] Embodiment 4

[0057] Refer to Figure 8-9, this structure also uses a traditional cylinder 2, except that the rotating pair 4 at the lower end of the cylinder 2 is moved upward and installed on the base through the cylinder mounting seat 13. The lower end of the cylinder 2 is fixed on the base 1, and the cylinder 2 is connected to the fixed plate 6 by a connecting rod 5. The connecting rod 5 and the piston rod of the cylinder 2 form a rotating pair 4, and the connecting rod 5 and the fixed plate 6 form a ball joint or a Hooke joint 10.

[0058] The working principle and beneficial effects of the present invention are as follows: This paint surface defect grinding device has a series of remarkable technical effects. In terms of grinding accuracy, the cylinder 2 can inversely solve the telescopic distance according to the constructed approximate plane equation, and independently adjust the optimal angle and grinding force of the grinding tool 8. After adjusting to the best angle, each cylinder 2 extends forward synchronously to the preset grinding pressure, and maintains a constant pressure throughout the grinding process through the control valve group to ensure high-quality grinding. The structural design endows it with high flexibility. The fixed plate 6 and the cylinder 2 are connected by a Hooke joint 10 or a ball joint, greatly improving the degree of freedom of the fixed plate 6. Cooperating with at least three cylinders 2 and connecting rods 5, the angle between the grinding tool 8 and the paint surface can be accurately and flexibly adjusted to meet the diverse grinding requirements of different paint surfaces and defects. The ranging sensor 9 measures the distance from the paint surface in real time, providing key data support for angle adjustment. The device has excellent environmental adaptability. Using the pneumatic method, it can be safely applied to explosion-proof environments, expanding the usage scenarios. At the same time, the compression property of the gas makes the pneumatic system have stronger force control anti-interference ability compared with the electric system, ensuring the stability of the force output during the grinding process. From the overall structure, the parallel setting of the frame fixed plate 3 and the base 1 and the circular through-hole design, combined with the connection of the rotating pair 4 in the middle of the cylinder 2, ensure the stability of the device structure and are conducive to accurate grinding. The fixed plate 6 integrally installs the ranging sensor 9, the motor 7 and the grinding tool 8, making the device structure compact and convenient for operation and control. In summary, this grinding device provides an efficient and reliable solution for the repair of paint surface defects with accurate grinding, flexible adjustment, good adaptability and stable structure.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A paint surface defect grinding device, characterized in that Comprising: A base (1) and a grinding assembly. Three cylinders (2) are provided on the base (1), and the cylinders (2) are perpendicular to the upper surface of the base (1). The three cylinders (2) are respectively connected to the grinding assembly, and the grinding assembly includes a fixing plate (6), a motor (7), a ranging sensor (9) and a grinding tool (8).

2. The paint surface defect grinding device according to claim 1, characterized in that, Comprising: A frame fixing plate (3) is provided at the top of the cylinder (2). The frame fixing plate (3) is parallel to the upper surface of the base (1), and a circular through hole is provided at the center of the frame fixing plate (3).

3. A paint surface defect grinding device according to claim 2, characterized in that, Comprising: A rotating pair (4) is fixedly connected to the middle part of the cylinder (2) through a connecting block.

4. A paint surface defect grinding device according to claim 3, characterized in that, Comprising: A connecting rod (5) is rotatably connected to the rotating pair (4).

5. A paint surface defect grinding device according to claim 4, characterized in that, Comprising: The connecting rod (5) passes through the circular through hole.

6. A paint surface defect grinding device according to claim 4, characterized in that, Comprising: The top of the connecting rod (5) is connected to the bottom surface of the fixing plate (6) through a Hooke's joint (10).

7. A paint surface defect grinding device according to claim 1, characterized in that, Comprising: The motor (7) is fixedly connected to the fixing plate (6).

8. A paint surface defect grinding device according to claim 1, characterized in that, Comprising: Three ranging sensors (9) are fixedly connected to the fixing plate (6).

9. The surface defect grinding device according to claim 1, characterized in that, Comprising: The grinding tool (8) is fixedly connected to the top of the motor (7).

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