A parallel type electromagnetic adsorption wall-climbing robot for curved surface polishing

Abstract

The present application relates to polishing robot technical field, especially a kind of parallel electromagnetic adsorption wall-climbing robot for curved surface polishing, including robot shell, electromagnetic adsorption mechanism, adaptive wheel group and 3RSS-U parallel polishing device.Slot is arranged at the cladding plate of robot shell with interval, for installing electromagnetic adsorption mechanism and mackenna wheel group with shock absorber, so that robot can be stably adsorbed and adaptively moved on complex curved surface.3RSS-U parallel polishing device located in the inside of shell, through three evenly distributed series motion branches and a central air bag type cylinder connection fixed platform and movable platform with polishing head, realizes the three-degree-of-freedom precision polishing movement of two rotation one movement, the present application has large range of movement ability, high rigidity operation characteristics and excellent curved surface adaptability, especially suitable for the automatic polishing operation of complex curved surface such as ship, large storage tank etc.

Description

Technical Field

[0001] This invention relates to the field of polishing robot technology, specifically to a parallel electromagnetic adsorption wall-climbing robot designed for polishing curved surfaces. Background Technology

[0002] Large metal components, such as ship hulls, aircraft surfaces, and chemical storage tanks, require surface treatments such as grinding, rust removal, and polishing during their manufacturing and maintenance. Currently, these tasks are mainly performed manually or with semi-automated equipment, resulting in low efficiency, inconsistent quality, and low grinding precision.

[0003] In this field, there are wall-climbing robots based on serial robotic arms and dedicated track-type or frame-type robots. Serial robotic arms have the advantage of large workspace but low rigidity, low precision, and slow response, making it impossible to achieve high-precision, high-force, and stable grinding, which affects surface quality. Dedicated track-type or frame-type robots require the pre-installation of rigid tracks or the construction of frames. The system has good rigidity but poor versatility and weak adaptability, and can only adapt to workpieces with fixed sizes and shapes.

[0004] In summary, existing technologies lack a grinding and wall-climbing robot capable of free movement over a wide range, high rigidity and stable operation, and adaptive adaptation to unknown curved surfaces. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a parallel electromagnetic adsorption wall-climbing robot for curved surface grinding.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a parallel electromagnetic adsorption wall-climbing robot for curved surface grinding, comprising a robot shell, an electromagnetic adsorption mechanism disposed on the robot shell, an adaptive wheel set, and an RSS-U parallel grinding device. The robot shell includes a polygonal plate and a covering plate connected to the outer periphery of the polygonal plate and forming a cylindrical surface; multiple equally spaced slots are opened along the outer circumference of the covering plate, and multiple electromagnetic adsorption mechanisms and multiple adaptive wheel sets are arranged in the slots at intervals. The electromagnetic adsorption mechanism includes a first movable secondary guide rail disposed in the slot, an electromagnet slidably disposed on the first movable secondary guide rail, a battery for supplying power to the electromagnet, and a spring for resetting the electromagnet. The adaptive wheel assembly includes a Mecanum wheel, a first motor that drives the Mecanum wheel, and a shock absorber connected between the Mecanum wheel and the robot housing. The RSS-U parallel grinding device is located inside the polygonal plate and includes a fixed platform connected to the polygonal plate, a moving platform equipped with a grinding head, three series motion branches connected between the fixed platform and the moving platform, and an airbag device located in the middle of the three series motion branches.

[0007] In some embodiments, the polygonal plate is a hexagonal plate, and the cylindrical surface formed by the covering plate is a prism surface.

[0008] In some embodiments, the two sides of the slot are parallel to the edges of the prism face, and one end of the slot passes through the bottom end of the covering plate; two first movable auxiliary guide rails are fixed along the two sides of the slot respectively, and the two sides of the electromagnet are slidably engaged with the first movable auxiliary guide rails through the first movable auxiliary sliders; the spring is connected between the first movable auxiliary sliders and the spring fixing bracket fixed on the slot.

[0009] In some embodiments, the adaptive wheel set further includes a first wheel set mounting bracket and a second wheel set mounting bracket, and the two ends of the shock absorber are respectively connected to the robot shell and the Mecanum wheel through the first wheel set mounting bracket and the second wheel set mounting bracket; the motor shaft of the first motor directly drives the axle of the Mecanum wheel.

[0010] In some embodiments, each of the series motion branches sequentially includes a bearing housing mounted on a fixed platform, a first revolute joint, a first connecting rod, a first ball joint, a second connecting rod, and a second ball joint; the airbag device includes an airbag cylinder, a first cylinder bearing housing, a Hooke's joint, and a second cylinder bearing housing.

[0011] In some embodiments, the three tandem motion branches are evenly distributed around the airbag device.

[0012] In some embodiments, the bearing housing is connected to the first link via the first revolute joint, the first link is connected to the second link via the first ball joint, and the second link is connected to the moving platform via the second ball joint.

[0013] In some embodiments, the bottom of the airbag cylinder is fixed to a fixed platform via a first cylinder bearing seat, and its top is connected to the Hooke hinge via a first rotating shaft of the Hooke hinge. The Hooke hinge is then connected to the second cylinder bearing seat via its second rotating shaft, and the second cylinder bearing seat is fixed to a moving platform.

[0014] In some embodiments, the first rotary joint is a drive joint; the airbag cylinder can output linear motion in the vertical direction.

[0015] In some embodiments, the moving platform can achieve three degrees of freedom spatial motion, consisting of two rotations and one translation, by driving the first rotary joint and the airbag cylinder.

[0016] Compared with the prior art, the beneficial effects of the present invention are: by setting a parallel mechanism of 3RSS-U and a grinding head, the present invention has the advantages of high precision, good rigidity, fixed axis of rotation, easy control, large working range, and flexible spatial movement. It can be used in the grinding of large curved parts, improve processing efficiency, improve processing accuracy, and save processing time.

[0017] 1. Integrated Adaptive Mobile Adsorption Platform: A unique hexagonal shell and prism-shaped bread-covered plate structure are designed, with independently extendable electromagnetic adsorption mechanisms and shock-absorbing adaptive wheel sets spaced apart within the circumferential slots. The electromagnetic adsorption mechanism achieves adaptive adhesion and rapid detachment of the adsorption surface through spring reset and sliding pairs, ensuring stable adsorption and flexible movement of the robot on complex curved surfaces.

[0018] 2. High-rigidity curved surface adaptability for grinding end: An innovative 3RSS-U parallel mechanism is adopted as the grinding actuator. This mechanism consists of three evenly distributed RSS motion branches and a central U-joint (composed of a pneumatic cylinder and a Hooke joint) connected in series. By driving the rotary joints of the three branches and the pneumatic cylinder, the moving platform can achieve three degrees of freedom motion (two rotations and one translation), combining the high rigidity and high precision advantages of parallel mechanisms, and achieving adaptive normal fitting of the grinding head to the curved surface through passive / active adjustment of the pneumatic cylinder.

[0019] 3. System Integration and Operating Mode: The system organically integrates a highly mobile platform with a high-rigidity end effector. When not in use, the grinding device can retract into its protective housing; during operation, it can precisely extend and adapt to curved surfaces. This design achieves a balance between mobility and operational performance, solving the challenge of automated grinding of large curved surfaces.

[0020] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. The embodiments of this application will provide a detailed description and understanding of the application. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention; Figure 2 for Figure 1 A three-dimensional structural diagram of the robot's outer shell; Figure 3 for Figure 2 A three-dimensional structural diagram of the electromagnetic adsorption mechanism; Figure 4 for Figure 1A three-dimensional structural diagram of the adaptive wheel assembly; Figure 5 for Figure 1 A three-dimensional structural diagram of the grinding device with the 3RSS-U parallel mechanism; Figure 6 for Figure 5 A schematic diagram of the three-dimensional structure of the first branch; Figure 7 for Figure 5 A three-dimensional structural diagram of the central airbag device.

[0022] In the diagram: 1. Robot shell; 11. Covering plate; 12. Electromagnetic adsorption mechanism; 13. First sliding block slider; 14. First sliding guide rail; 15. Spring; 16. Spring fixing frame; 17. First wheel set fixing frame; 2. Electromagnetic adsorption mechanism; 21. Spring fixing frame; 22. Electromagnetic adsorption mechanism; 23. Adsorption surface; 24. First battery; 3. Adaptive wheelset; 31. Shock absorber; 32. Second wheelset mounting bracket; 33. First motor; 34. Mecanum wheel; 4. Parts to be polished; 5. 3RSS-U parallel grinding device; 51. Moving platform equipped with grinding head; 52. Fixed platform connected to the inner side of polygonal plate; 53. Grinding head; 54. Frame bearing seat; 55. First rotating joint; 56. First connecting rod; 57. First ball joint; 58. Second connecting rod; 59. Second ball joint; 510. Airbag cylinder; 511. First cylinder bearing seat; 512. Second cylinder bearing seat; 513. Second Hooke joint. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: Basic Structure Example This embodiment describes in detail the basic structure, connection relationship and working principle of a parallel electromagnetic adsorption wall-climbing robot for curved surface grinding.

[0025] See Figure 1The robot in this embodiment consists of four core subsystems: robot shell 1, electromagnetic adsorption mechanism 2, adaptive wheel set 3, and 3RSS-U parallel polishing device 5. The robot shell 1 serves as the main load-bearing body, with three electromagnetic adsorption mechanisms 2 and three adaptive wheel sets 3 evenly and alternately arranged on its outer periphery. The 3RSS-U parallel polishing device 5 is installed at the inner center of the robot shell 1.

[0026] 1. Robot shell like Figure 2 As shown, the robot shell 1 is the robot's skeleton and main load-bearing structure. Its core includes a polygonal flat plate (in this preferred embodiment, it may be a hexagonal flat plate) and a covering plate 11 that is vertically connected to all the outer edges of the hexagonal flat plate and extends downwards integrally. The space enclosed by the covering plate 11 forms a cylindrical surface (corresponding to the hexagonal flat plate, this cylindrical surface is a prism), making the shell as a whole resemble a downward-opening "bench" or "brim" structure. This design ensures structural strength while providing installation space and protection for the internal mechanisms.

[0027] To achieve the adsorption and movement functions, six elongated slots are equally spaced along the outer circumference of the prismatic covering plate 11. The two sides of these slots are parallel to the edges of the prism face, and the lower end of the slot (the end away from the hexagonal plate) is continuous. These six slots are used to alternately install the electromagnetic adsorption mechanism 2 and the adaptive wheel set 3.

[0028] 2. Electromagnetic adsorption mechanism The electromagnetic adsorption mechanism 2 is key to enabling the robot to firmly adhere to the surface of magnetically conductive workpieces such as steel. For example... Figure 2 and Figure 3 As shown, each electromagnetic adsorption mechanism 2 is independently installed in a slot.

[0029] Moving and guiding components: A first sliding guide rail 14 is fixedly installed on each side edge of each slot. An electromagnet 22 is slidably mounted on the two first sliding guide rails 14 via first sliding sliders 13 connected to its two sides. This allows the electromagnet 22 to slide up and down along the slot, i.e., in a direction perpendicular to the workpiece surface.

[0030] Adsorption and power supply components: The lower end face of the electromagnet 22 forms the adsorption surface 23. The electromagnet 22 is connected to the battery 24 that powers it via a wire. The battery 24 can be fixedly installed inside the robot shell 1 or on the upper part of the electromagnet 22. When the battery 24 is powered, the electromagnet 22 generates a strong magnetic field, which firmly attracts the surface of the magnetically conductive workpiece below through the adsorption surface 23.

[0031] Adaptive Reset Component: This is crucial for achieving surface adaptation. The mechanism includes a spring 15 to reset the electromagnets. The upper end of the spring 15 is connected to a spring holder 16 fixed to the top or side wall of the slot, and the lower end is connected to the first sliding block 13 or a connected component. Its working principle is as follows: When the robot is placed on an uneven surface, under the influence of gravity and magnetism, the adsorption surfaces 23 of each electromagnet 22 extend and adhere to the surface to varying degrees. At this time, the spring 15 is stretched. When the robot needs to be moved (i.e., the electromagnets are de-energized), the magnetism disappears, and under the restoring force of the spring 15, the electromagnet 22 is pulled back to its initial position, detaching from the workpiece surface. This "extend-adhere-spring reset" mechanism allows each electromagnetic adsorption point to independently adapt to changes in the local surface height, ensuring the overall stability of the adsorption and the ease of detachment.

[0032] 3. Adaptive Wheelset The adaptive wheel set 3 is responsible for the robot's omnidirectional movement and ground adaptation. For example... Figure 4 As shown, each adaptive wheel set 3 is also independently installed in a slot and arranged at intervals with the electromagnetic adsorption mechanism 2.

[0033] Drive and locomotion components: The core component is a Mecanum wheel 34. The Mecanum wheel 34 is directly driven by a first motor 33, and the motor shaft of the first motor 33 is connected to the wheel axle of the Mecanum wheel 34. The specific arrangement of the three Mecanum wheels 34 enables the robot to achieve omnidirectional movements such as linear movement, lateral movement, and rotation within a plane.

[0034] Shock Absorption and Connection Components: To accommodate bumps during movement on curved surfaces and ensure the wheels remain in contact with the surface, shock absorbers 31 are provided. The upper end of the shock absorber 31 is connected to the robot shell 1 (such as the covering plate 11 or inner plate) via a first wheel assembly mounting bracket 17, and the lower end is connected to the bracket of the Mecanum wheel 34 via a second wheel assembly mounting bracket 32. The shock absorber 31 (such as a pneumatic or hydraulic shock absorber) allows the Mecanum wheel 34 to float up and down relative to the shell to a certain extent, thereby cushioning impacts and ensuring that all drive wheels can effectively contact the ground on uneven curved surfaces, providing continuous driving force.

[0035] 4. 3RSS-U parallel grinding device This device serves as the robot's operational mechanism, integrating high rigidity and adaptability to curved surfaces. For example... Figure 5 As shown, it mainly includes a fixed platform 52, a moving platform 51, three series motion branches, and a central airbag device.

[0036] Platform: The fixed platform 52 is fixedly connected to the center of the inner side of the hexagonal plate of the robot shell 1. The moving platform 51 is located below the fixed platform 52, and a grinding head 53 (such as a pneumatic or electric grinding disc, belt sander head, etc.) is installed at its lower end.

[0037] Three sequential motion branches (RSS branches): such as Figure 5 and Figure 6 As shown, three branches are evenly distributed around the periphery of the airbag device. Each branch has an identical structure; taking one branch as an example: A bearing housing 54 is fastened to the fixed platform 52 by bolts.

[0038] The first rotary joint 55 (i.e., R-joint) is mounted in the bearing housing 54, and its rotation axis is along the radial direction of the fixed platform 52. The first rotary joint 55 is a drive joint, driven by a servo motor (not shown in the figure) mounted on the fixed platform 52.

[0039] One end of the first connecting rod 56 is fixedly connected to the output end of the first rotating joint 55 and rotates with it.

[0040] The other end of the first link 56 is connected to the upper end of the second link 58 via the first ball joint 57 (i.e., S-joint).

[0041] The lower end of the second link 58 is connected to the moving platform 51 via the second ball joint 59 (i.e., S-joint).

[0042] The axes of the first revolute joint 55 of the three branches are at 120° angles to each other in the horizontal plane. This arrangement ensures the symmetry of the mechanism and the stability of its motion.

[0043] Central airbag unit (U-type): such as Figure 5 and Figure 7 As shown, the device is connected at the center of the fixed platform 52 and the moving platform 51, realizing one translational degree of freedom (P joint in the U joint) and two rotational degrees of freedom (two orthogonal R joints in the U joint).

[0044] The air-filled cylinder 510 is arranged vertically. The bottom of its cylinder body is firmly fixed to the fixed platform 52 by the first cylinder bearing seat 511.

[0045] The piston rod of the air-filled cylinder 510 is connected at the top of a first Hooke hinge 513 (i.e., a universal hinge) to a first rotating shaft 514. The axial direction of the first rotating shaft 514 is defined as the X-direction.

[0046] The second rotating shaft 515 of the first Hooke hinge 513 is perpendicular (i.e., in the Y direction) to the first rotating shaft 514. The second rotating shaft 515 is fixedly connected to the center of the moving platform 51 through the second cylinder bearing seat 512.

[0047] Therefore, the extension and retraction of the air-filled cylinder 510 itself provides linear motion in the vertical direction (Z direction) (P joint). The first Hooke joint 513 provides two rotational degrees of freedom about the X-axis and about the Y-axis (two R joints), which together form a U joint.

[0048] The air-filled cylinder 510 can be driven by a pneumatic system. Its internal air pressure is adjustable. It can not only provide active telescopic movement, but also act as a compliant element to passively adapt to the normal force fluctuations during the grinding process, protecting the mechanism and the workpiece.

[0049] 5. Working principle and kinematics The robot's workflow in this embodiment is as follows: Positioning and Adsorption: The operator or auxiliary equipment places the robot on the surface of the large steel component to be polished. The control system powers the battery 24 of the electromagnetic adsorption mechanism 2, and the three electromagnets 22 slide downward under the action of magnetic force, the adsorption surface 23 closely fits the curved surface, and the spring 15 is stretched. The robot is firmly adsorbed onto the workpiece.

[0050] Movement and Positioning: The first motor 33 drives the Mecanum wheel 34 to rotate. According to the preset grinding path plan, the speed and direction of the three wheels are controlled to enable the robot to move omnidirectionally on the curved surface until it reaches the first grinding point. During the movement, the shock absorber 31 buffers the vibration, and the electromagnetic adsorption mechanism 2 maintains adsorption at all times.

[0051] Grinding operation: After the robot arrives at the work point, the 3RSS-U parallel grinding device 5 starts working.

[0052] Attitude adjustment: By coordinating the servo motors that drive the three first rotary joints 55, the length changes of the three RSS branches can be controlled, thereby driving the moving platform 51 to rotate around the X-axis and around the Y-axis (i.e., two rotational degrees of freedom), so that the grinding head 53 is adjusted to the expected attitude aligned with the normal direction of the local curved surface.

[0053] Contact and constant force grinding: The pneumatic cylinder 510 inflates and extends, pushing the moving platform 51 and grinding head 53 downward (one degree of freedom of movement) until the grinding head 53 contacts the workpiece surface with a set pressure. During grinding, the air pressure of the pneumatic cylinder 510 can be controlled in a closed loop to maintain a constant normal grinding force. At the same time, its inherent compliance can absorb some of the impact.

[0054] Surface tracking: When the robot moves along a curved surface for continuous grinding, the direction of the normal at the grinding point also changes due to the change in the curvature of the surface. The control system uses feedback from sensors (such as force sensors and tilt sensors) to adjust the three first rotary joints 55 and the airbag cylinder 510 in real time, so that the posture and contact force of the grinding head 53 always adapt to the curved surface, achieving high-quality tracking grinding.

[0055] Finishing and Transfer: After grinding an area is completed, the pneumatic cylinder 510 retracts, lifting the grinding head 53. The electromagnetic adsorption mechanism 2 is de-energized, and under the action of the spring 15, the electromagnet 22 resets and detaches from the workpiece surface. The robot can then move freely under the drive of the Mecanum wheel 34 to the next work area or remove the workpiece.

[0056] The working principle of this invention, based on the technical solution of this application, is as follows: In the unpolished state, the 3RSS parallel polishing device 5 retracts into the covering plate and is protected; the three adaptive wheel sets 3 are also inside the covering plate. In the working state, the invention is first placed on the surface of the part 4 to be polished, and is attracted to the surface of the part by the magnetic force of the electromagnet after being energized; the first motor is turned on so that the invention can move on the surface of the part to be polished according to the designed path; finally, the driver of the 3RSS-U parallel polishing device is started, so that the polishing head moves downward and extends to polish the surface of the part. After polishing, all moving parts can return to their initial state.

[0057] This parallel wall-climbing robot can perform grinding on large and complex curved surfaces. It uses electromagnets to attract and release the electromagnet portion of the robot's shell, allowing it to engage and disengage with the large metal curved surface. Combined with a 3RSS-U parallel mechanism, this enables the robot to perform grinding operations on large and complex curved surfaces. Once the robot reaches the designated processing position, the grinding head mounted on the lower platform can perform high-precision machining on the large and complex curved surface.

[0058] In summary, the robot in this embodiment, through its defined structure, successfully combines an adaptive mobile adsorption platform with a high-rigidity, compliant parallel grinding end, achieving autonomous, stable, and high-precision automated grinding operations on large, complex curved surfaces. Example 2: Modified Example of Electromagnetic Adsorption Mechanism This embodiment, based on Embodiment 1, focuses on optimizing and modifying the electromagnetic adsorption mechanism 2 to demonstrate its design flexibility.

[0059] Variant 1: Hybrid Adsorption of Permanent Magnet and Electromagnet. Electromagnet 22 can be replaced with a hybrid magnet consisting of a permanent magnet core and an excitation coil. Under normal conditions, the permanent magnet provides the basic attraction force to ensure safety; when movement is required, the coil, through which a reverse current is applied, cancels out part of the magnetic force, allowing spring 15 to more easily pull the magnet back. This reduces energy consumption during movement and provides fail-safe protection.

[0060] Variation 2: Parallel connection of multiple springs and enhanced guidance. For heavier robots or those requiring greater resetting force, a single spring 15 can be replaced with multiple springs connected in parallel, or a disc spring assembly can be used. Simultaneously, the first gliding auxiliary guide rail 14 can be a linear ball bearing guide rail, and the first gliding auxiliary slider 13 can be a corresponding slider to reduce friction, making the up-and-down sliding of the electromagnet 22 smoother and the response faster.

[0061] Variant 3: Position sensor integration. Miniature displacement sensors (such as magnetic scales or LVDTs) are installed on the first sliding block 13 or electromagnet 22 to monitor the extension of each electromagnet 22 in real time. This data is fed back to the control system and can be used to roughly perceive the curved surface contour of the robot's bottom, providing auxiliary information for path planning and attitude prediction.

[0062] The variations in this embodiment do not deviate from the core features of "the electromagnetic adsorption mechanism includes a sliding pair, an electromagnet, a battery, and a return spring," but are performance optimizations based on this, and all fall within the protection scope of this invention. Example 3: Adaptive Wheelset and Chassis Modification Example This embodiment mainly demonstrates the possible variations of the adaptive wheel set 3 and the overall mobile chassis.

[0063] Variant 1: Wheel Replacement. The Mecanum wheel 34 can be replaced with an omni-wheel or a traditional combination of drive wheel and steering wheel, depending on actual needs. The omni-wheel also achieves omnidirectional movement, but the structure is slightly different; the combination of drive wheel and steering wheel achieves movement through differential and steering, and although it is not omnidirectional, the structure is simpler and more reliable. Regardless of the wheel type used, its combination with the shock absorber 31 and the first motor 33 achieves the function of "adaptive movement".

[0064] Variant 2: Active Suspension System. The passive shock absorbers 31 are upgraded to active or semi-active suspension (such as electro-hydraulic shock absorbers). The control system dynamically adjusts the damping or height of each shock absorber 31 based on data from the wheel assembly force sensor or the machine attitude sensor (IMU), actively maintaining the horizontal stability of the machine body. Even on curved surfaces with large tilt angles or bumps, it ensures that the grinding platform (fixed platform 52) is in the optimal working posture.

[0065] Variation 3: Changes in the number and layout of wheel sets. This refers to "multiple" adaptive wheel sets. In this variation, four adaptive wheel sets 3 and four electromagnetic adsorption mechanisms 2 can be set, and the polygonal flat plate of the robot shell 1 is correspondingly designed as an octagon, with the covering plate 11 forming an octagonal prism surface. More support points may bring better stability. This change in number and layout still follows the core arrangement method of "intermittent arrangement in slots".

[0066] The variations of this embodiment all revolve around the core concept that "the adaptive wheelset includes a Mecanum wheel, a drive motor, and a shock absorber," and are reasonable extensions of its specific implementation. Example 4: Modified Example of 3RSS-U Parallel Grinding Device This embodiment elaborates on various implementation methods and optimized design of the 3RSS-U parallel grinding device 5.

[0067] Variant 1: Refined Drive Method. The first rotary joint 55 is the drive joint. Its drive can be achieved by a servo motor in conjunction with a harmonic reducer, planetary reducer, or worm gear, directly driving the first connecting rod 56 to rotate. The drive of the pneumatic cylinder 510 can be replaced by a high-precision proportional pneumatic servo valve, electric cylinder, or ball screw module to achieve more precise displacement and force control. When using an electric cylinder, the "pneumatic" feature of the central U-joint evolves into an "electric telescopic rod," but its function of providing single-degree-of-freedom linear motion and constituting the U-joint remains unchanged.

[0068] Variant 2: Optimized airbag device structure. The first Hooke hinge 513 can be a precision universal hinge composed of crossed roller bearings to withstand greater bending and overturning moments. The airbag cylinder 510 can be designed as a dual-chamber or multi-chamber structure. By controlling the pressure of different chambers separately, it can not only achieve extension and retraction but also fine-tune its lateral stiffness, enhancing the anti-interference capability of the moving platform 51.

[0069] Variation 3: Fine-tuning of branch configuration. The second link 58 of the three tandem motion branches can be designed with a finely adjustable length (e.g., via a threaded sleeve) for precise calibration of the mechanism's initial zero position and symmetry during assembly. The first ball joint 57 and the second ball joint 59 can employ rod end bearings for ease of installation and maintenance.

[0070] Variant 4: End-of-line tool quick change. A standard tool quick-change interface (such as an ISO9409 standard flange) is integrated on the moving platform 51, allowing the grinding head 53 to be quickly replaced with a polishing wheel, milling head, cleaning nozzle, or inspection probe (such as a 3D scanner), expanding the robot's application functions and achieving multi-purpose functionality.

[0071] All variations of this embodiment retain the core topology of the 3RSS-U parallel mechanism, which consists of "three RSS branches surrounding a central U-type sub-sub ... Example 5: Control System and Operating Method Example This embodiment describes, from the perspective of control system and overall working method, how to drive and coordinate the hardware of the aforementioned embodiments to complete complex surface polishing tasks.

[0072] Subsystem control: Motion control unit: responsible for processing path planning algorithms (such as offline planning based on curved CAD models or online planning based on vision), solving the speed commands of the three Mecanum wheels 34, and controlling the first motor 33 (usually a DC brushless motor with an encoder) to achieve precise movement and positioning.

[0073] Adsorption control unit: manages the power-on and power-off sequence of the electromagnetic adsorption mechanism 2. For example, before movement, a wave-like sequence of "on first, then off" is used to ensure that there is always sufficient magnetic force to prevent the robot from slipping.

[0074] Parallel mechanism control unit: This is the core. It receives pose information from the moving platform and feedback from end effectors (six-dimensional force / torque sensor, proximity sensor). Based on the grinding process requirements (constant force, constant speed), it solves the inverse kinematics of the 3RSS-U mechanism in real time. That is, based on the desired pose of the moving platform 51 (two rotation angles, one movement), it calculates the rotation angles of the three first rotary joints 55 and the extension / retraction setpoints of the pneumatic cylinder 510, and drives the corresponding servo motors and pneumatic servo valves.

[0075] Surface adaptation working method: Local adaptation under a global path: The robot moves along a globally planned path. Upon reaching a grinding point, the contact force is detected by the end effector force sensor. If the force value deviates from the set value, the control system immediately adjusts the pressure of the pneumatic cylinder 510 (or the position of the electric cylinder), changing the Z-axis movement; simultaneously, based on the force distribution or a pre-defined surface model, the three first rotary joints 55 are adjusted, changing the tilt angle of the moving platform 51 (two rotations), so that the grinding head 53 is realigned with the surface normal. This is a dynamic "force-position hybrid control" process.

[0076] The combination of passive adaptation and active compensation: The airbag compliance of the 510 airbag cylinder itself provides passive force buffering. The active control system then provides precise compensation based on this, together achieving robust tracking of unknown or variable curvature surfaces.

[0077] Safety and Monitoring: The system integrates an inertial measurement unit (IMU), tilt sensor, and fall protection sensor to monitor the aircraft's attitude in real time. Upon detecting abnormal tilt or a risk of adsorption failure, all movement is immediately stopped, the mechanism is locked, and a safety alarm is activated. Example 6: Typical Application Scenarios This embodiment describes the application scenarios of the robot of the present invention in different industrial fields to demonstrate its wide applicability.

[0078] Scenario 1: Shipbuilding and Repair. Used for grinding welds, removing rust, and surface treatment before painting on ship hull steel plates. The robot adheres to vertical or curved ship hull plates, replacing manual high-altitude work, significantly improving efficiency and ensuring uniform quality.

[0079] Scenario 2: Aerospace. Used for grinding and polishing aircraft fuselage skin and wing surfaces. Its lightweight design (achieved through material selection) and high-precision adaptability can meet the high-quality aerodynamic shape requirements of aircraft surfaces.

[0080] Scenario 3: Energy and Chemical Industry. Used for the routine maintenance and polishing of large spherical storage tanks, wind turbine towers, and the outer shells of nuclear power facilities. The robot can work stably on complex hyperboloid surfaces and adapt to harsh environments.

[0081] Scenario 4: Large steel structure buildings. Surface treatment used for bridge steel box girders, stadium steel structures, and high-rise building curtain wall support structures.

[0082] In all these scenarios, the robot of the present invention can demonstrate its comprehensive advantages of "flexible movement, stable adsorption, good grinding rigidity, and adaptive curved surface", which verifies the outstanding practicality and creativity of the defined technical solution.

[0083] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A parallel electromagnetic adsorption wall-climbing robot for curved surface grinding, comprising a robot shell (1), an electromagnetic adsorption mechanism (2) disposed on the robot shell (1), an adaptive wheel set (3), and a 3RSS-U parallel grinding device (5), characterized in that: The robot shell (1) includes a polygonal plate and a covering plate (11) connected to the outer periphery of the polygonal plate and forming a cylindrical surface; a plurality of equally spaced slots are provided along the outer circumference of the covering plate (11), and a plurality of electromagnetic adsorption mechanisms (2) and a plurality of adaptive wheel sets (3) are arranged in the slots at intervals. The electromagnetic adsorption mechanism (2) includes a first movable secondary guide rail (14) disposed in the slot, an electromagnet (22) slidably disposed on the first movable secondary guide rail (14), a battery (24) supplying power to the electromagnet (22), and a spring (15) for resetting the electromagnet (22). The adaptive wheel assembly (3) includes a Mecanum wheel (34), a first motor (33) that drives the Mecanum wheel (34), and a shock absorber (31) connected between the Mecanum wheel (34) and the robot housing (1). The 3RSS-U parallel grinding device (5) is located on the inner side of the polygonal plate and includes a fixed platform (52) connected to the polygonal plate, a moving platform (51) provided with a grinding head (53), three series motion branches connected between the fixed platform (52) and the moving platform (51), and an airbag device located in the middle of the three series motion branches.

2. The parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 1, characterized in that: The polygonal plate is a hexagonal plate, and the cylindrical surface formed by the covering plate (11) is a prism surface.

3. The parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 2, characterized in that: The two sides of the slot are parallel to the edges of the prism face, and one end of the slot passes through the bottom end of the covering plate (11); the two first moving auxiliary guide rails (14) are fixed along the two sides of the slot respectively, and the two sides of the electromagnet (22) are slidably engaged with the first moving auxiliary guide rails (14) through the first moving auxiliary sliders (13); the spring (15) is connected between the first moving auxiliary sliders (13) and the spring fixing bracket (16) fixed on the slot.

4. The parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 1, characterized in that: The adaptive wheel set (3) also includes a first wheel set mounting bracket (17) and a second wheel set mounting bracket (32). The two ends of the shock absorber (31) are connected to the robot shell (1) and the Mecanum wheel (34) respectively through the first wheel set mounting bracket (17) and the second wheel set mounting bracket (32). The motor shaft of the first motor (33) directly drives the wheel axle of the Mecanum wheel (34).

5. A parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 1, characterized in that: Each of the aforementioned serial motion branches includes, in sequence, a bearing seat (54), a first rotating joint (55), a first connecting rod (56), a first ball joint (57), a second connecting rod (58), and a second ball joint (59) mounted on a fixed platform (52); the airbag device includes an airbag cylinder (510), a first cylinder bearing seat (511), a Hooke joint (513), and a second cylinder bearing seat (512).

6. A parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 5, characterized in that: The three tandem motion branches are evenly distributed around the airbag device.

7. A parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 5, characterized in that: The bearing seat (54) is connected to the first connecting rod (56) through the first rotating joint (55), the first connecting rod (56) is connected to the second connecting rod (58) through the first ball joint (57), and the second connecting rod (58) is connected to the moving platform (51) through the second ball joint (59).

8. A parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 5, characterized in that: The bottom of the airbag cylinder (510) is fixed on the fixed platform (52) via the first cylinder bearing seat (511), and its top is connected to the Hooke hinge (513) via the first rotating shaft (514). The Hooke hinge (513) is then connected to the second cylinder bearing seat (512) via its second rotating shaft (515). The second cylinder bearing seat (512) is fixed on the moving platform (51).

9. A parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claims 5 or 8, characterized in that: The first rotary joint (55) is a drive joint; the airbag cylinder (510) can output linear motion in the vertical direction.

10. A parallel electromagnetic adsorption wall-climbing robot for curved surface grinding according to claim 9, characterized in that: By driving the first rotary joint (55) and the airbag cylinder (510), the moving platform (51) can achieve three-degree-of-freedom spatial motion with two rotations and one translation.

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