An adaptive track sanding device and method for complex curved surfaces

Abstract

This invention discloses an adaptive track sanding device and method for complex curved surfaces. The device includes: a flange seat, a universal joint at the front end of the flange seat, a motor body disposed within the universal joint, and a brake ring and a grinding disc at the output end of the motor body. The universal joint is a circular ring structure, rotatably connected to the front end of the flange seat by a first pin. The upper part of the motor body passes through the universal joint, and the two are rotatably connected by a second pin. The connecting lines formed by the first and second pins intersect, allowing the motor body to rotate in two degrees of freedom. By rotating the motor body via the universal joint, the contact surface between the grinding disc and the surface to be sanded is adjusted, achieving adaptive sanding of the surface. This ensures that the normal of the grinding disc coincides with the normal of the curved surface without requiring precise adjustment of the robot's posture or positioning accuracy, thus achieving a better sanding effect.

Description

Technical Field

[0001] This invention belongs to the field of sanding equipment technology, and more specifically, relates to an adaptive track sanding device and method for complex curved surfaces. Background Technology

[0002] A sander is a power tool widely used for grinding the surface of workpieces. A track sander uses slight rotation or track motion to move the object's surface for sanding or polishing, achieving fine grinding. Currently, sanding equipment used in robotic grinding mostly employs a manual disc sander connected to a force-controlled tool via a connecting flange. The force-controlled tool used for disc sanders typically uses single-axis adaptive control of displacement and pressure. During grinding, it is necessary to ensure that the normal to the grinding disc surface coincides with the normal to the curved surface to obtain a relatively uniform grinding effect.

[0003] Chinese patent CN106239319A discloses a sanding mechanism, which includes a connecting back plate, an upper plate, a lower plate, a motor, and a sanding disc. The upper plate is fixed to the connecting back plate, and the upper and lower plates are spaced apart and connected by several connecting rods. The upper end of the connecting rod is connected to the upper plate, and the lower end of the connecting rod is connected to the lower plate through a spherical bearing. The motor is fixed to the upper surface of the lower plate, and the output shaft of the motor passes through the lower plate and is fixedly connected to the sanding disc located below the lower plate. It offers high flexibility, capable of sanding not only smooth surfaces but also curved surfaces with small curvatures. It also boasts advantages such as high production efficiency, good sanding quality, and effective protection of workpiece edges and corners.

[0004] However, Chinese patent CN106239319A states that when the normal of the surface to be sanded does not coincide with the normal of the grinding disc, the contact point between the grinding disc and the surface is located at the edge of the grinding disc. The edge of the grinding disc transmits the downward pressure of the force control tool, and the edge of the grinding disc has a relatively high linear velocity, making it prone to over-grinding and resulting in indentations on the surface, leading to uneven removal of material. Therefore, an adaptive track sanding device and method for complex curved surfaces is needed, which adds a surface adaptive mechanism to ensure that the grinding disc normal and the surface normal adaptively align during the sanding process of complex curved surfaces, thus guaranteeing the uniformity of sanding quality. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides an adaptive track sanding device and method for complex curved surfaces. This device enables the sanding disc to rotate in all directions. Because the force points on the sanding disc are uneven or not in the center, the motor body rotates via a universal cross to adjust the contact surface between the sanding disc and the surface to be sanded, thus achieving adaptive sanding. This ensures that the normal of the sanding disc coincides with the normal of the curved surface without requiring precise adjustments to the robot's posture or positioning accuracy, thereby achieving a better sanding effect.

[0006] To achieve the above objectives, according to a first aspect of the present invention, an adaptive track sanding device for complex curved surfaces is provided, comprising a flange seat, a universal cross disposed at the front end of the flange seat, a motor body disposed in the universal cross, and a brake ring and a grinding disc disposed at the output end of the motor body.

[0007] The universal cross is a circular structure and is rotatably connected to the front end of the flange seat by a first pin. The upper part of the motor body passes through the universal cross, and the two are rotatably connected by a second pin.

[0008] The connecting lines formed by the first and second pins intersect at a cross, and the motor body achieves two degrees of freedom of rotation through these two pins.

[0009] Furthermore, the rear end of the flange seat is a cylinder with one end open, and its open end is symmetrically provided with an extension as a mounting plate.

[0010] The universal cross is installed at the front end of the mounting plate and rotates on the flange seat around the first pin.

[0011] The outer ring of the motor body is provided with a fixing frame, which is connected to the inner ring of the universal cross and rotates on the universal cross around the second pin.

[0012] Furthermore, when the grinding disc contacts the surface to be ground, because the force points of the grinding disc are uneven or not in the center, the motor body rotates through the universal cross to adjust the contact surface between the grinding disc and the surface to be ground, so that the normal of the grinding disc coincides with the normal of the surface to be ground.

[0013] Furthermore, the flange seat is also provided with a plurality of spring seats, which are evenly distributed on the open end face of the flange seat and located between the two mounting plates of the flange seat;

[0014] A spring is provided between the spring seat and the fixing frame of the motor body. Multiple springs ensure that the motor body is evenly stressed. When no external force is applied, the motor body always remains aligned with the axis of the sanding device under the action of multiple springs.

[0015] Furthermore, the front end of the motor body is provided with a dust removal hood, and an air inlet is opened around the dust removal hood. Multiple guide plates are arranged from the air inlet toward the middle to form a guide plate array. A dust suction port is also provided on one side of the dust removal hood for connecting an external dust collector.

[0016] Furthermore, the motor body includes a motor housing, a rear end cover located at the rear end of the motor housing, a front end cover located at the front end of the motor housing, and a brushless motor located within the motor housing.

[0017] Furthermore, the motor housing is also provided with holes evenly spaced around its circumference, and a silencer is provided in each hole. The rear end cover is also provided with an air pipe connector for introducing compressed air. A damping ring is also provided between the motor housing and the rear end cover, and the damping ring is provided with multiple small holes as guide holes.

[0018] After compressed air is introduced into the air pipe connector, the airflow passes through the guide hole on the damping ring and enters the motor body, and then flows out from the muffler to dissipate heat from the motor body. The compressed air also creates positive pressure in the motor body to prevent dust generated by the grinding disc at the front end from entering the motor body.

[0019] Furthermore, the output end of the brushless motor is provided with an eccentric body, the center of which is fixedly connected to the output shaft of the brushless motor. An eccentric block is provided at the front end away from the center, and multiple heat dissipation fins are provided at equal intervals along the rear end face to form a heat dissipation fin array. The heat dissipation fin array is opposite to the guide plate array.

[0020] Furthermore, the grinding disc is mounted on the eccentric block of the eccentric body via a connecting pin, and the connecting pin and the eccentric block are connected by a connecting bearing. The grinding disc and the eccentric body are always in a moving state, and there is an eccentricity between the grinding disc and the output shaft of the brushless motor.

[0021] According to a second aspect of the present invention, an adaptive track sanding method for complex curved surfaces is provided, specifically including the following steps:

[0022] S100. Connect the sanding device to the robot's force control tool via the flange seat, and ensure that the motor body can rotate freely at multiple angles via the universal joint.

[0023] S200. Adjust the robot's posture so that the grinding disc is roughly aligned with the surface to be ground. Start the brushless motor, and the motor will drive the grinding disc to rotate.

[0024] S300 When the grinding disc contacts the surface to be ground, the motor body adjusts its angle adaptively through the universal cross to make the normal of the grinding disc coincide with the normal of the surface to be ground because the force points of the grinding disc are uneven or not in the center.

[0025] S400, start the external dust collector. The suction generated by the dust collector effectively sucks up and collects the dust generated during the polishing process.

[0026] S500: The rotation of the motor and the rotation of the eccentric couple are combined to form the rotation of the grinding disc through the eccentric body. The friction between the brake ring and the grinding disc makes the movement trajectory of the sandpaper and abrasive particles on the grinding disc a random cycloidal motion.

[0027] S600. For the edge of the curved surface to be polished, a single-acting cylinder is used to lock the normal direction of the polishing disc to prevent excessive swaying of the polishing disc during edge polishing, which would cause over-polishing of the edge of the curved surface.

[0028] S700: When the sandpaper reaches the end of its lifespan, the robot moves the sander to the automatic sandpaper tearing mechanism and activates a single-acting cylinder to lock the normal direction of the sanding disc, preventing the sanding disc from swaying during the sandpaper tearing process, thereby improving the success rate of sandpaper replacement.

[0029] After S800 finishes grinding, stop the brushless motor and quickly brake the grinding disc using the brake ring to end the grinding operation.

[0030] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0031] 1. In the sanding device of the present invention, the connecting lines of the first pin shaft and the connecting lines of the second pin shafts at both ends cross each other. The motor body achieves two degrees of freedom of rotation through the first and second pin shafts, so that the grinding disc can achieve omnidirectional rotation. Since the force points of the grinding disc are uneven or not in the center position, the motor body rotates through the omnidirectional cross to adjust the contact surface between the grinding disc and the surface to be ground, so as to achieve adaptive grinding of the surface. It can ensure that the normal of the grinding disc coincides with the normal of the surface without the need for precise adjustment of the robot posture and positioning accuracy, thereby obtaining a better grinding effect.

[0032] 2. In the sanding device of the present invention, multiple springs ensure that the motor body is evenly stressed. When no external force is applied, the motor body remains aligned with the axis of the sanding device under the action of the multiple springs. When the sanding device does not contact the surface to be sanded, the swaying caused by the weight of the sanding device and external interference forces is balanced, preventing accidental contact before friction when it comes into contact with the surface to be sanded, which could lead to damage or local over-sanding of the surface to be sanded.

[0033] 3. In the sanding device of the present invention, a sliding friction pair is formed between the brake ring and the grinding disc. During the grinding process, the frictional resistance of the brake ring on the grinding disc causes the movement trajectory of the sandpaper grains on the grinding disc to be a random cycloidal motion, which makes the surface quality obtained after grinding more uniform and consistent. In addition, during the shutdown process, the brake ring can quickly brake the grinding disc.

[0034] 4. In the sanding device of the present invention, the suction force generated by the external dust collector allows outside air to enter the dust collection hood through the air inlet. After entering the dust collection hood, the air flows on the heat dissipation fin array, carrying the heat therein to achieve heat dissipation for the sanding device. At the same time, under the action of high-speed centrifugation, dust particles escape from the edge of the heat dissipation fins and are finally sucked into the dust collector through the dust suction port, effectively preventing dust from entering the motor body or bearings.

[0035] 5. In the sanding device of the present invention, the rotational motion of the sanding disc is a combination of the rotational motion of the motor and the rotational motion of the eccentric body, which generate the rotational motion of the sanding disc. During the sanding process, the movement trajectory of each abrasive grain on the sandpaper attached to the sanding disc is a random track. The random movement of the abrasive grains during the sanding process can obtain a more uniform and consistent sanding quality.

[0036] 6. In the sanding device of the present invention, when it is necessary to lock the normal direction of the sanding device, the piston rod of the single-acting cylinder acts on the concave ring on the motor body, and the sanding device will not swing, thus playing a locking role. When sanding the edge of the curved surface, locking the sanding device prevents the sanding device from excessively swinging and causing excessive sanding of the edge.

[0037] 7. In the sanding device of the present invention, when the sandpaper reaches the end of its lifespan, the robot moves the sander to the automatic sandpaper tearing mechanism and activates a single-acting cylinder to lock the normal direction of the sanding disc, preventing the sanding disc from swaying during the sandpaper tearing process, thereby improving the success rate of sandpaper replacement. Attached Figure Description

[0038] Figure 1 This is an exploded view of the structure of an adaptive track sanding device for complex curved surfaces according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the structure of an adaptive track sanding device for complex curved surfaces according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram illustrating the positional relationship between the grinding disc and the surface to be ground in a traditional method.

[0041] Figure 4 This is a schematic diagram showing the positional relationship between the grinding disc and the surface to be ground in Embodiment 1 of the present invention;

[0042] Figure 5 This is a schematic diagram of the motor body structure of an adaptive track sanding device for complex curved surfaces according to an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the eccentric body installation of an adaptive track sanding device for complex curved surfaces according to an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the installation of a single-acting cylinder in an adaptive track sanding device for complex curved surfaces, according to an embodiment of the present invention.

[0045] Figure 8 This is a schematic diagram showing the positional relationship between the grinding disc and the surface to be ground in Embodiment 2 of the present invention;

[0046] Figure 9This is a schematic flowchart of an adaptive track sanding method for complex curved surfaces according to an embodiment of the present invention.

[0047] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-flange seat, 2-single-acting cylinder, 3-first pin, 4-first oilless bearing, 5-spring seat, 6-spring, 7-universal cross, 8-second pin, 9-second oilless bearing, 10-motor body, 11-dust hood, 12-brake ring, 13-grinding disc, 1001-air pipe connector, 1002-concave ring, 1003-rear end cover, 1004-damping ring, 1005-motor housing, 1006-silencer, 1007-brushless motor, 1008-front end cover, 1009-eccentric body, 1010-connecting bearing, 1011-connecting shaft. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0049] Example 1

[0050] like Figure 1 , 2 As shown, this embodiment of the invention provides an adaptive track sanding device for complex curved surfaces, including a flange seat 1, a universal cross 7 disposed at the front end of the flange seat 1, a motor body 10 disposed in the universal cross 7, and a brake ring 12 and a grinding disc 13 disposed at the output end of the motor body 10. The universal cross 7 is a ring structure, connected to the front end of the flange seat 1 along a diameter by a first pin 3. The upper part of the motor body 10 passes through the universal cross 7, leaving a certain gap between them, and the two are also connected along a diameter by a second pin 8. The connecting line of the first pin 3 and the connecting line of the two second pins 8 intersect at both ends. The motor body 10 achieves two degrees of freedom of rotation through the first pin 3 and the second pin 8, so that the grinding disc 13 can achieve universal rotation, realizing adaptive grinding of the curved surface to be ground. It can ensure that the normal of the grinding disc coincides with the normal of the curved surface without the need for precise adjustment of the robot posture and positioning accuracy, thereby obtaining a better grinding effect.

[0051] The rear end of the flange seat 1 is a cylindrical body with one open end. Multiple mounting holes are provided at its bottom, and symmetrical extensions extending from the open end to the front end serve as mounting plates. The universal cross 7 is mounted to the front end of this mounting plate via a first pin 3 and rotates around the first pin 3 on the flange seat 1. A fixing bracket is provided on the outer ring of the motor body 10, and this fixing bracket is rotatably connected to the inner ring of the universal cross 7 via a second pin 8. When the grinding disc 13 contacts the surface to be ground, due to uneven force distribution or the grinding disc 13 being off-center, the motor body 10 rotates via the universal cross 7 to adjust the contact surface between the grinding disc 13 and the surface to be ground, ensuring that the normal of the grinding disc 13 coincides with the normal of the surface to be ground.

[0052] like Figure 3 , 4 As shown, traditional robotic sanding equipment uses force-controlled tools with only axial self-adaptation. When the normal of the surface to be sanded does not coincide with the normal of the grinding disc, the contact point between the grinding disc and the surface is located at the edge of the grinding disc. The edge of the grinding disc transmits the downward pressure of the force-controlled tool, and the edge of the grinding disc has a relatively high linear velocity, which easily leads to over-sanding and resulting in depressions on the surface after sanding, and the overall surface exhibits uneven sanding removal. In contrast, in this invention, the first pin 3, the universal cross 7, and the second pin 8 together form a ball-and-pin pair. This ball-and-pin pair releases two degrees of freedom of swing in the direction of the grinding disc normal. During the sanding process, the surface itself adjusts the grinding disc, allowing the sanding disc 13 of the sanding device to better fit the surface to be sanded. This ensures that the grinding disc normal and the surface normal adaptively fit during the sanding of complex surfaces, guaranteeing the uniformity of sanding quality.

[0053] To ensure the flexibility of the ball joint rotation and reduce rotational wear, a first oilless bearing 4 is installed at the connection between the first pin 3 and the flange seat 1, and a second oilless bearing 9 is installed at the connection between the motor body 10 and the universal joint 7. The universal joint has one degree of rotational freedom relative to the flange seat 1, and the motor body 10 has one degree of rotational freedom relative to the universal joint 7. During the grinding process, the sanding device passively adapts to the curved surface.

[0054] The flange seat 1 is also provided with multiple spring seats 5, which are evenly distributed on the open end face of the flange seat 1 and located between the two mounting plates of the flange seat 1. A spring 6 is provided between the spring seat 5 and the fixing frame of the motor body 10. The multiple springs 6 ensure that the motor body 10 is evenly stressed. When no external force is applied, the multiple springs 6 keep it aligned with the axis of the sanding device. Before the sanding device contacts the surface to be sanded, the springs balance the weight of the sanding device and the swaying caused by external interference forces, preventing accidental contact before friction when it comes into contact with the surface to be sanded, which could lead to damage or localized over-sanding of the surface.

[0055] The front end of the motor body 10 is also provided with a dust removal hood 11. Air inlets are opened around the dust removal hood 11, and multiple guide plates are arranged from the air inlets towards the center to form a guide plate array. A suction port is also provided on one side of the dust removal hood 11 for connecting to an external dust collector. During the grinding process, the dust collector generates suction, and air enters the dust removal hood 11 from the air inlets along the guide plate array, drawing the grinding dust from the suction port into the dust collector to achieve the purpose of dust removal.

[0056] The brake ring 12 is a rubber ring that forms a sliding friction pair with the grinding disc 13. During the grinding process, the frictional resistance of the brake ring 12 against the grinding disc 13 causes the sandpaper grains on the grinding disc 13 to move in a random cycloidal motion, resulting in a more uniform surface quality after grinding. Furthermore, during shutdown, the brake ring 12 can quickly brake the grinding disc 13.

[0057] like Figure 5 , 6 As shown, the motor body 10 includes a motor housing 1005, a rear end cover 1003 located at the rear end of the motor housing 1005, a front end cover 1008 located at the front end of the motor housing 1005, and a brushless motor 1007 housed within the motor housing 1005. The motor housing 1005 also has evenly spaced holes along its circumference, each containing a muffler 1006. The rear end cover 1003 has an air pipe connector 1001 for introducing compressed air. A damping ring 1004 is located between the motor housing 1005 and the rear end cover 1003, and the damping ring 1004 has multiple small holes serving as airflow guides. After compressed air is introduced into the air pipe connector 1001, the airflow passes through the airflow guides on the damping ring 1004 and enters the motor body 10, then exits from the muffler 1006, dissipating heat from the motor body 10 and preventing overheating during operation from affecting the grinding effect. Furthermore, compressed air is introduced into the motor body 10 to create positive pressure in its internal space, preventing dust generated by the grinding disc 13 at its front end from entering its interior and damaging its parts, thus extending the service life of the sanding device.

[0058] The output end of the brushless motor 1007 is provided with an eccentric body 1009, the center of which is fixedly connected to the output shaft of the brushless motor 1007. An eccentric block is located at the front end of the eccentric body 1009 away from the center, and multiple heat dissipation fins are equidistantly arranged along the rear end face to form a heat dissipation fin array. This heat dissipation fin array is opposite to the guide plate array. The suction force generated by the external dust collector draws outside air into the dust collector 11 through the air inlet. The air then flows over the heat dissipation fin array, carrying heat to dissipate heat from the sanding device. Simultaneously, under the action of high-speed centrifugation, dust particles escape from the edges of the heat dissipation fins and are ultimately sucked into the dust collector through the suction port, effectively preventing dust from entering the motor body 10 or the bearings.

[0059] The grinding disc 13 is mounted on an eccentric block on an eccentric body 1009 via a connecting pin 1011. The connecting pin 1011 and the eccentric block are connected by a connecting bearing 1010, ensuring that there is no circumferential constraint between the connecting pin 1011 and the eccentric body 1009, meaning the grinding disc 13 and the eccentric body 1009 are always in a dynamic state. The center of the pin 1011 and the center of the eccentric body 1009 are designed as an eccentric structure, meaning there is an eccentricity between the grinding disc 13 and the output shaft of the brushless motor 1007. The rotational motion of the grinding disc 13 is a combination of the rotational motion of the motor and the eccentric force couple generated by the rotational motion of the eccentric body 1009, resulting in the self-rotation of the grinding disc. During grinding, the trajectory of each abrasive grain on the sandpaper adhered to the grinding disc 13 is a random track, allowing for a more uniform grinding quality through the random movement of the abrasive grains.

[0060] like Figure 7 As shown, the rear end cover 1003 also has a concave ring 1002, which is embedded in the center of the rear end face of the rear end cover 1003. The surface has a concave conical structure. The inner bottom of the flange seat 1 also has a single-acting cylinder 2. When the piston rod of the single-acting cylinder 2 extends, it abuts against the concave ring 1002. When it is necessary to lock the normal direction of the sanding device, the piston rod of the single-acting cylinder acts on the concave ring 1002 on the motor body 10, and the sanding device will not swing, thus playing a locking role. When sanding the edge of a curved surface, locking the sanding device prevents excessive swing of the sanding device from causing excessive sanding of the edge. Moreover, when the sandpaper life reaches the end, when the robot moves the sander to the automatic sandpaper tearing mechanism, the single-acting cylinder is activated to lock the normal direction of the sanding disc, preventing the sanding disc from swinging during the sandpaper tearing process, thereby improving the success rate of sandpaper replacement.

[0061] The flange seat 1 is also connected to the robot end effector via a flange, and the movement of the sanding device is controlled by the robot end effector.

[0062] Example 2

[0063] like Figure 8As shown, this embodiment of the invention provides another adaptive track sanding device for complex curved surfaces. In this embodiment, all other aspects are the same as in Embodiment 1, except that the ball pin is positioned between the robot flange and the force control tool.

[0064] Example 3

[0065] like Figure 9 As shown, this embodiment of the invention provides an adaptive track sanding method for complex curved surfaces, specifically including the following steps:

[0066] S100. Connect the sanding device to the robot's force control tool via the flange seat, and ensure that the motor body 10 can rotate freely at multiple angles via the universal cross 7.

[0067] S200. Adjust the robot's posture so that the grinding disc 13 is roughly aligned with the position of the curved surface to be ground. Start the brushless motor 1007, and the motor drives the grinding disc 13 to rotate.

[0068] S300. When the grinding disc 13 contacts the surface to be ground, the force points of the grinding disc 13 are uneven or not in the center, so the motor body 10 adaptively adjusts the angle through the universal cross 7 so that the normal of the grinding disc 13 coincides with the normal of the surface to be ground.

[0069] S400, start the external dust collector. The suction generated by the dust collector effectively sucks up and collects the dust generated during the polishing process.

[0070] S500, the rotation of the motor and the rotation of the eccentric couple are combined by the eccentric body 1009 to form the rotation of the grinding disc, and the friction between the brake ring 12 and the grinding disc 13 causes the movement trajectory of the sandpaper and abrasive particles on the grinding disc to be a random cycloidal motion.

[0071] S600. For the edge of the curved surface to be polished, a single-acting cylinder 2 is used to lock the normal direction of the polishing disc 13 to prevent excessive swaying of the polishing disc 13 during edge polishing, which would cause excessive polishing of the edge of the curved surface.

[0072] S700: When the sandpaper reaches the end of its lifespan, the robot moves the sander to the automatic sandpaper tearing mechanism and activates the single-acting cylinder 2 to lock the normal direction of the grinding disc 13, preventing the grinding disc from swaying during the sandpaper tearing process, thereby improving the success rate of sandpaper replacement.

[0073] S800. After grinding is completed, stop the operation of the brushless motor 1007 and quickly brake the grinding disc 13 through the brake ring 12 to end the grinding operation.

[0074] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An adaptive track sanding device for complex curved surfaces, characterized in that, It includes a flange seat (1), a universal cross (7) located at the front end of the flange seat (1), a motor body (10) located in the universal cross (7), and a brake ring (12) and a grinding disc (13) located at the output end of the motor body (10). The universal cross (7) is a ring structure and is rotatably connected to the front end of the flange seat (1) by a first pin (3). The upper part of the motor body (10) passes through the universal cross (7) and the two are rotatably connected by a second pin (8). The connecting lines formed by the first pin (3) and the second pin (8) intersect at a cross, and the motor body (10) achieves two degrees of freedom of rotation through the two pins; The flange seat (1) is also provided with a plurality of spring seats (5), which are evenly distributed on the open end face of the flange seat (1) and located between the two mounting plates of the flange seat (1); A spring (6) is provided between the spring seat (5) and the fixing frame of the motor body (10). Multiple springs (6) make the motor body (10) uniformly subjected to force. When there is no external force, under the action of multiple springs (6), it always keeps its axis of the sanding device aligned. The motor body (10) includes a motor housing (1005), a rear end cover (1003) located at the rear end of the motor housing (1005), a front end cover (1008) located at the front end of the motor housing (1005), and a brushless motor (1007) located in the motor housing (1005). The rear end cover (1003) is also provided with a concave ring (1002), which is embedded in the center of the rear end face of the rear end cover (1003) and has a concave conical surface. The inner bottom of the flange seat (1) is also provided with a single-acting cylinder (2). When the piston rod of the single-acting cylinder (2) extends, it abuts against the concave ring (1002).

2. The adaptive track sanding device for complex curved surfaces according to claim 1, characterized in that, The rear end of the flange seat (1) is a cylinder with one end open, and its open end is symmetrically provided with an extension as a mounting plate. The universal cross (7) is installed at the front end of the mounting plate and rotates on the flange seat (1) around the first pin (3); The outer ring of the motor body (10) is provided with a fixing frame, which is connected to the inner ring of the universal cross (7) and rotates on the universal cross (7) around the second pin (8).

3. The adaptive track sanding device for complex curved surfaces according to claim 2, characterized in that, When the grinding disc (13) comes into contact with the surface to be ground, the motor body (10) rotates through the universal cross (7) because the force points of the grinding disc (13) are uneven or not in the center position, so that the contact surface between the grinding disc (13) and the surface to be ground is adjusted, so that the normal of the grinding disc (13) and the normal of the surface to be ground coincide.

4. An adaptive track sanding device for complex curved surfaces according to any one of claims 1-3, characterized in that, The front end of the motor body (10) is also provided with a dust removal hood (11). The dust removal hood (11) has an air inlet around it. Multiple guide plates are provided from the air inlet toward the middle to form a guide plate array. A dust suction port is also provided on one side of the dust removal hood (11) for connecting an external dust collector.

5. The adaptive track sanding device for complex curved surfaces according to claim 4, characterized in that, The motor housing (1005) is also provided with holes evenly distributed around its circumference, and a silencer (1006) is provided in each hole. The rear end cover (1003) is also provided with an air pipe connector (1001) for introducing compressed air. A damping ring (1004) is also provided between the motor housing (1005) and the rear end cover (1003). The damping ring (1004) has multiple small holes as guide holes. After compressed air is introduced into the air pipe connector (1001), the airflow passes through the guide hole on the damping ring (1004) and enters the motor body (10), and then flows out from the muffler (1006) to dissipate heat from the motor body (10). The compressed air is introduced into the motor body (10) to form a positive pressure in its internal space, preventing the dust generated by the grinding disc (13) at its front end from entering its interior.

6. The adaptive track sanding device for complex curved surfaces according to claim 5, characterized in that, The output end of the brushless motor (1007) is provided with an eccentric body (1009). The center of the eccentric body (1009) is fixedly connected to the output shaft of the brushless motor (1007). An eccentric block is provided at the front end away from the center. Multiple heat dissipation fins are provided at equal intervals along the end face of the rear end to form a heat dissipation fin array. The heat dissipation fin array is opposite to the guide plate array.

7. The adaptive track sanding device for complex curved surfaces according to claim 6, characterized in that, The grinding disc (13) is mounted on the eccentric block of the eccentric body (1009) via a connecting pin (1011), and the connecting pin (1011) and the eccentric block are connected by a connecting bearing (1010). The grinding disc (13) and the eccentric body (1009) are always in an active state, and there is an eccentricity between the grinding disc (13) and the output shaft of the brushless motor (1007).

8. An adaptive track sanding method for complex curved surfaces, implemented using an adaptive track sanding device for complex curved surfaces as described in any one of claims 1-7, characterized in that, Specifically, the following steps are included: S100. Connect the sanding device to the robot's force control tool via the flange seat, and ensure that the motor body (10) can rotate freely at multiple angles via the universal cross (7). S200. Adjust the robot's posture so that the grinding disc (13) is roughly aligned with the surface to be ground. Start the brushless motor (1007) and the motor drives the grinding disc (13) to rotate. S300. When the grinding disc (13) contacts the surface to be ground, the force points of the grinding disc (13) are uneven or not in the center position, so that the motor body (10) adaptively adjusts the angle through the universal cross (7) so that the normal of the grinding disc (13) coincides with the normal of the surface to be ground. S400, start the external dust collector. The suction generated by the dust collector effectively sucks up and collects the dust generated during the polishing process. S500, the rotation of the motor and the rotation of the eccentric couple are combined into the rotation of the grinding disc by the eccentric body (1009), and the friction between the brake ring (12) and the grinding disc (13) makes the movement trajectory of the sandpaper and abrasive particles on the grinding disc a random cycloidal motion. S600. For the edge of the curved surface to be polished, a single-acting cylinder (2) is used to lock the normal direction of the polishing disc (13) to prevent excessive swaying of the polishing disc (13) during edge polishing, which would cause excessive polishing of the edge of the curved surface. S700. When the lifespan of the sandpaper is reached, the robot moves the sander to the automatic sandpaper tearing mechanism and activates the single-acting cylinder (2) to lock the normal direction of the grinding disc (13) to prevent the grinding disc from swaying during the sandpaper tearing process, thereby improving the success rate of sandpaper replacement. S800. After grinding is completed, stop the operation of the brushless motor (1007) and quickly brake the grinding disc (13) through the brake ring (12) to end the grinding operation.

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