A robot soft grinding and polishing device

Abstract

The present invention discloses a robot compliant grinding and polishing device, comprising a robot body, a compliant connection device and a grinding and polishing tool; wherein the compliant connection device has a magnetorheological damping unit and an electromagnetic variable stiffness unit. The compliant grinding and polishing device of the present invention not only has active and passive vibration suppression functions, but also has the function of electromagnetically driven stiffness adjustment; the compliant grinding and polishing device of the present invention adopts magnetorheological damping to suppress the vibration of the robot during the grinding and polishing process, has good dynamic response and large load-bearing capacity; at the same time, the stiffness of the compliant grinding and polishing device is regulated by current regulation, which can effectively adapt to the change of grinding and polishing load, effectively suppress the vibration during the grinding and polishing process and adapt to the change of grinding and polishing load through vibration suppression and stiffness adjustment, and realize the compliant grinding and polishing operation of the robot.

Description

Technical Field

[0001] The invention relates to a grinding and polishing device, in particular to a robot compliant grinding and polishing device with vibration control and stiffness adjustment functions, belonging to the technical field of intelligent manufacturing. Background Art

[0002] Grinding and polishing are common types of operations in the industrial field. Robotic grinding and polishing, in particular, is increasingly used in scenarios such as steel polishing, ceramic sanitary ware, marble, high-speed rail bodies, and wind turbine blades. Among them, the end effector is a key component of robotic grinding and polishing, and its performance largely determines the performance of the entire robotic operation system.

[0003] In the prior art, "Robot Polishing Force / Position Hybrid Control Method Based on Passive Compliance" proposes a robot polishing system force / position hybrid control strategy based on a passive compliance device. A compliance device is installed at the end of the robot to achieve decoupling of the tool end force control and position control. One end of the compliance device is installed at the end of the robot, and the other end is connected to the polishing tool. The robot controller controls the robot end posture, and the compliance device controller directly controls the contact force between the tool and the workpiece. However, the prior art has the following problems: First, due to the low stiffness characteristics of the robot body, residual vibration is also easy to generate during the operation process. At the same time, especially for elastic thin-walled parts, elastic vibration is easy to occur during the polishing process. These vibration factors affect the stability of the robot polishing; second, the existing research on polishing devices is mainly to achieve constant force control, but the robot polishing has poor adaptive adjustment ability to dynamic changes in load, and it is difficult to achieve polishing vibration control and stiffness adjustment according to load changes. Summary of the invention

[0004] The purpose of the present invention is to provide a robot compliant grinding and polishing device with a simple structure, active and passive vibration suppression functions and stiffness adjustment functions in order to solve at least one of the above-mentioned technical problems. The robot compliant grinding and polishing device isolates or suppresses the vibration generated during the grinding and polishing process, adapts to the dynamic changes of the grinding and polishing load, and is of great value to the stable grinding and polishing of the robot.

[0005] The present invention achieves the above-mentioned object through the following technical solutions: A robot compliant grinding and polishing device comprises a robot body, a compliant connection device and a grinding and polishing tool;

[0006] The compliant connection device includes an upper connection flange, a magnetorheological damping unit, an electromagnetic variable stiffness unit, a support frame, a polishing connection flange, a force sensor and a displacement sensor;

[0007] The upper end of the magnetorheological damping unit is connected to the upper connecting flange, and the lower end of the magnetorheological damping unit is connected in series with the electromagnetic variable stiffness unit;

[0008] The electromagnetic variable stiffness unit is located inside the support frame, and the lower end of the electromagnetic variable stiffness unit is connected to the grinding and polishing connection flange through a force sensor;

[0009] The upper end of the support frame is connected to the magnetorheological damping unit, the lower end of the support frame is connected to the polishing connection flange, and the displacement sensor is fixed on the magnetorheological damping unit.

[0010] As a further technical solution of the present invention: the magnetorheological damping unit is composed of a magnetic conductive ring, an upper end cover, an electromagnetic coil I, a magnetic isolation ring, a magnetorheological fluid, a magnetorheological pressure plate, a guide rod and a lower end cover;

[0011] Among them, the electromagnetic coil I is wound in the cavity of the magnetic isolation ring, and a through hole I is reserved at the lower end of the magnetic isolation ring for leading out the wire. The guide rod is connected to the magnetic fluid pressure plate, and the magnetic conductive ring is connected to the upper end cover and the lower end cover. The magnetorheological fluid fills the area surrounded by the magnetic fluid pressure plate, the upper end cover, the lower end cover, and the magnetic isolation ring. The upper end cover is provided with a sealing groove I, and the lower end cover is provided with a sealing groove II and a sealing groove III for sealing the magnetorheological fluid. A through hole II is reserved at the lower end of the lower end cover and cooperates with the through hole I to lead out the wire in the electromagnetic coil I.

[0012] As a further technical solution of the present invention: the electromagnetic variable stiffness unit is composed of an electromagnetic coil II, a magnetic isolation plate, an armature, and a permanent magnet;

[0013] Among them, the electromagnetic coil II is wound in the cavity connected by the armature and the magnetic isolation plate. A through hole III is left at the upper end of the magnetic isolation plate for the guide rod to pass through. The armature has an internal thread for matching with the external thread of the guide rod. The permanent magnet is a hollow annular permanent magnet in the middle to facilitate the insertion of the linear bearing I.

[0014] As a further technical solution of the present invention: the support frame is composed of a support column, a guide rod, a support plate, a support spring, a linear bearing I, and a linear bearing II;

[0015] Among them, the upper end of the support column is connected to the lower end cover, and the lower end of the support column is connected to the support plate. Through holes IV and V are left in the middle and around the support plate to facilitate the insertion of linear bearings I and II. The support spring is inserted into the guide rod, and a threaded hole III is left at the lower end of the guide rod to cooperate with the grinding and polishing connecting flange.

[0016] As a further technical solution of the present invention: the grinding and polishing connecting flange is a "convex" shaped flange with a raised truncated cone in the middle, a threaded hole I is reserved in the middle of the convex cone of the grinding and polishing connecting flange for connection with the force sensor, and threaded holes II and stepped holes are reserved around it for matching the grinding and polishing tools and guide rods.

[0017] As a further technical solution of the present invention: the displacement sensor fixing plate has a "T"-shaped plate, and a through hole VI and a through hole VII are left on the displacement sensor fixing plate.

[0018] As a further technical solution of the present invention: the displacement sensor reflector plate has a "Z" shape, a through hole VIII is left on the displacement sensor reflector plate for matching with the grinding and polishing connecting flange, and a through hole IX passes through the guide rod for positioning.

[0019] As a further technical solution of the present invention: the guide rod is in the shape of a stepped rod with threads, an external thread is left at the middle step portion of the guide rod, a threaded hole IV is left at the upper end of the guide rod, and a threaded hole V is left at the lower end.

[0020] As a further technical solution of the present invention: the support column has an outer shape of an I-shaped hollow column with symmetrical upper and lower ends and bidirectional cut edges, and threaded holes VI are left at the upper and lower ends of the support column.

[0021] The beneficial effects of the present invention are:

[0022] 1) The flexible grinding and polishing device of the present invention not only has the active and passive vibration suppression functions, but also has the electromagnetically driven stiffness adjustment function. The flexible grinding and polishing device of the present invention adopts magnetorheological damping to suppress the vibration of the robot during the grinding and polishing process, has good dynamic response and large load-bearing capacity;

[0023] 2) The present invention realizes the regulation of the stiffness of the flexible grinding and polishing device through current regulation, which can effectively adapt to the changes in the grinding and polishing load. Through vibration suppression and stiffness adjustment, the vibration in the grinding and polishing process can be effectively suppressed and the changes in the grinding and polishing load can be adapted, thereby realizing the flexible grinding and polishing operation of the robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a structural diagram of the robot grinding and polishing device of the present invention;

[0025] Figure 2 It is a structural diagram of the soft grinding and polishing device of the present invention;

[0026] Figure 3 It is a structural diagram of the magnetorheological damping unit of the present invention;

[0027] Figure 4 is a cross-sectional view of a magnetorheological damping unit of the present invention;

[0028] Figure 5 It is a structural diagram of the electromagnetic variable stiffness unit of the present invention;

[0029] Figure 6 is a cross-sectional view of the electromagnetic variable stiffness unit of the present invention;

[0030] Figure 7 It is a connection structure diagram of the support frame of the present invention;

[0031] Figure 8 is a cross-sectional view of the support frame of the present invention;

[0032] Fig. 9 It is a connection cross-sectional view of the grinding and polishing connection flange of the present invention;

[0033] Fig.10 It is a structural diagram of the grinding and polishing connection flange of the present invention;

[0034] Fig.11 It is a structural diagram of a displacement sensor fixing plate of the present invention;

[0035] Fig.12 It is a structural diagram of the displacement sensor reflector of the present invention;

[0036] Fig.13 is a cross-sectional view of a guide rod of the present invention;

[0037] Fig.14 It is a structural diagram of the support column of the present invention;

[0038] Fig.15 It is the force diagram of the electromagnetic variable stiffness unit of the present invention;

[0039] In the figure:

[0040] 001, Robotic arm, 002, Soft connection device, 003, Grinding and polishing tool, 004, Workpiece,

[0041] 100. Upper connecting flange,

[0042] 200, magnetorheological damping unit, 210, magnetic conductive ring,

[0043] 220, upper end cover, 221, sealing groove Ⅰ,

[0044] 230. Electromagnetic coil I,

[0045] 240, magnetic isolation ring, 241, through hole I,

[0046] 250, magnetorheological fluid, 260, magnetic fluid pressure plate,

[0047] 270, guide rod, 271, external thread, 272, threaded hole IV, 273, threaded hole V,

[0048] 280, lower end cover, 281, sealing groove II, 282, sealing groove III, 28, through hole II,

[0049] 300, electromagnetic variable stiffness unit, 310, electromagnetic coil II,

[0050] 320, magnetic isolation plate, 321, through hole III,

[0051] 330, armature, 340, permanent magnet,

[0052] 400, support frame, 410, support column, 420, guide rod,

[0053] 430, support plate, 431, through hole IV, 432, through hole V,

[0054] 440, support spring, 500, polished connection flange, 510, threaded hole Ⅰ, 520, threaded hole Ⅱ, 530, stepped hole, 600, force sensor, 700, displacement sensor,

[0055] 710, displacement sensor fixing plate, 711, through hole VI, 712, through hole VII,

[0056] 720, displacement sensor reflector, 721, through hole VIII, 722, through hole IX,

[0057] A01, screw Ⅰ, A02, screw Ⅱ, A03, screw Ⅲ, A04, screw Ⅳ,

[0058] C01, linear bearing Ⅰ, C02, linear bearing Ⅱ,

[0059] D01, nut. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Embodiment 1, as Figure 1 As shown, a robot compliant grinding and polishing device includes a robot body 001, a compliant connection device 002 and a grinding and polishing tool 003.

[0062] like Figure 2 As shown, the compliant connection device 002 includes an upper connection flange 100, a magnetorheological damping unit 200, an electromagnetic variable stiffness unit 300, a support frame 400, a polishing connection flange 500, a force sensor 600 and a displacement sensor 700; wherein, the upper end of the magnetorheological damping unit 200 is connected to the upper connection flange 100, and the lower end is connected in series with the electromagnetic variable stiffness unit 300; the electromagnetic variable stiffness unit 300 is located inside the support frame 400, and the lower end of the electromagnetic variable stiffness unit 300 is connected to the polishing connection flange 500 through the force sensor 600; the upper end of the support frame 400 is connected to the magnetorheological damping unit 200, and the lower end is connected to the polishing connection flange 500, and the displacement sensor 700 is fixed on the magnetorheological damping unit 200.

[0063] like Figure 3 and Figure 4As shown, the magnetorheological damping unit 200 is composed of a magnetic conductive ring 210, an upper end cover 220, an electromagnetic coil I 230, a magnetic isolation ring 240, a magnetorheological fluid 250, a magnetic fluid pressure plate 260, a guide rod 270 and a lower end cover 280; wherein, the electromagnetic coil I 230 is wound in the cavity of the magnetic isolation ring 240, a through hole I 241 is left at the lower end of the magnetic isolation ring 240 for the lead-out of the wire, the magnetic isolation ring 240 is inserted into the interior of the magnetic conductive ring 210, the upper end of the guide rod 270 passes through the lower end cover 280 and is connected to the magnetic fluid pressure plate by screws I A01, and the magnetic conductive ring The upper and lower ends of the ring 210 are connected to the upper end cover 220 and the lower end cover 280 respectively through screws ⅡA02. The magnetorheological fluid 250 fills the area surrounded by the magnetic fluid pressure plate 260 and the upper end cover 220, the lower end cover 280 and the magnetic isolation ring 240. The upper end cover 220 is provided with a sealing groove Ⅰ221, and the lower end cover 280 is provided with a sealing groove Ⅱ281 and a sealing groove Ⅲ282 for sealing the magnetorheological fluid 250. The lower end of the lower end cover is provided with a through hole Ⅱ283 which cooperates with the through hole Ⅰ241 for leading out the wire in the electromagnetic coil Ⅰ230.

[0064] like Figure 5 and Figure 6 As shown, the electromagnetic variable stiffness unit 300 is composed of an electromagnetic coil II 310, a magnetic isolation plate 320, an armature 330 and a permanent magnet 340; wherein, the electromagnetic coil II 310 is wound in a cavity connected to the armature 330 and the magnetic isolation plate 320, a through hole III 321 is reserved at the upper end of the magnetic isolation plate 320 for the guide rod 270 to pass through, the magnetic isolation plate 320 is fixed to the upper end of the armature 330 by glue, the armature 330 is reserved with an internal thread 331 for matching with the external thread 271 of the guide rod 270, the permanent magnet 340 is a hollow annular permanent magnet in the middle to facilitate the insertion of the linear bearing IC01, and the permanent magnet 340 is fixed to the support plate 430 by glue; wherein the magnetic isolation plate 320 is used to eliminate the influence of the magnetic field generated by the electromagnetic coil II 310 on the magnetorheological damping unit 200.

[0065] like Figure 7 and Figure 8 As shown, the support skeleton 400 is composed of a support column 410, a guide rod 420, a support plate 430, a support spring 440, a linear bearing IC01 and a linear bearing IC02; wherein, the upper end of the support column 410 is connected to the lower end cover 280, and the lower end is connected to the support plate 430. The middle and surrounding of the support plate 430 are provided with through holes IV431 and V432 for the insertion of the linear bearing IC01 and the linear bearing IC02 and are fixed to the support plate 430 by screws IA01 and IA02. The support spring 440 is inserted into the upper end of the guide rod 420 and contacts the lower end of the guide rod 420 and contacts the linear bearing IC02. The lower end of the guide rod 420 is provided with a threaded hole III421 and is connected to the polishing connection flange 500 by screws IIIA03.

[0066] like Fig. 9 and Fig.10 As shown, the grinding and polishing connecting flange 500 is a "convex" shaped flange with a raised truncated cone in the middle. A threaded hole I 510 is left in the middle of the convex cone of the grinding and polishing connecting flange 500 for connecting with the force sensor 600, and threaded holes II 520 and stepped holes 530 are left around it for matching the grinding and polishing tool 003 and the guide rod 420.

[0067] like Fig.11 As shown, the displacement sensor fixing plate 710 has a "T"-shaped plate shape, and a through hole VI711 is left on the displacement sensor fixing plate 710, which is fixed to the displacement sensor 700 by screws IVA04 and nuts D01, and a through hole VII712 on the displacement sensor fixing plate 710 is fixed to the lower end cover 280 by screws IIA02.

[0068] like Fig.12 As shown, the displacement sensor reflector plate 720 has a "Z" shape, and a through hole VIII 721 is reserved on the displacement sensor reflector plate 720 for cooperating with the polishing connection flange 500, and a through hole IX 722 passes through the guide rod 420 for positioning, and the displacement sensor reflector plate 720 is used to cooperate with the displacement sensor 700 to receive signals.

[0069] like Fig.13 As shown, the guide rod 270 is in the shape of a stepped rod with threads, and an external thread 271 is reserved at the middle step portion of the guide rod 270 for cooperating with the armature 330, a threaded hole IV 272 is reserved at the upper end of the guide rod for cooperating with the magnetic flow pressure plate 260, and a threaded hole V 273 is reserved at the lower end for cooperating with the force sensor 600.

[0070] like Fig.14 As shown, the support column 410 is an I-shaped hollow column with symmetrical upper and lower ends and bidirectional cut edges. Threaded holes VI411 are left at the upper and lower ends of the support column 410 for matching with the lower end cover 280 and the support plate 430.

[0071] Embodiment 2, in addition to the robot compliant grinding and polishing device in Embodiment 1, this embodiment also includes a method for vibration control and variable stiffness of the robot compliant grinding and polishing device:

[0072] The working process of the magnetorheological damping unit 200 is as follows: when the polishing tool 003 polishes the workpiece 004, the vibration of the workpiece 004 will cause the fluctuation of the polishing load. At this time, the force sensor 600 and the displacement sensor 700 will detect the vibration information and reversely infer the control current of the electromagnetic coil I 230 according to the vibration control algorithm; the current change will cause the viscosity coefficient of the magnetorheological fluid 250 in the magnetorheological damping unit 200 to change, and the viscous damping force on the magnetorheological pressure plate 260 during the movement will be enhanced. Under the action of the damping force, the vibration generated by the workpiece 004 is suppressed.

[0073] The working process of the electromagnetic variable stiffness unit 300 is as follows: when the grinding and polishing tool 003 just contacts the workpiece 004, the current of the electromagnetic coil II 310 is adjusted to generate an electromagnetic force F; the electromagnetic force F drives the grinding and polishing tool 003 connected in series with the guide rod 270 to press down the workpiece 004. At this time, the electromagnetic force F acts as a grinding and polishing load to press the workpiece 004. The workpiece 004 generates a reaction force P that acts with the electromagnetic force F to keep the electromagnetic coil II 310 and the permanent magnet 340 at a distance δ; when the grinding and polishing load changes, the reaction force P of the workpiece 004 changes accordingly. By adjusting the current of the electromagnetic coil II 310, the strength of the magnetic field and the electromagnetic force F near the electromagnetic coil II 310 are adjusted, so that it is still at a distance δ from the permanent magnet 340, and the force balance of different grinding and polishing loads is achieved under the same displacement, thereby realizing the variable stiffness adjustment of the flexible connection device 002.

[0074] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0075] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A robot compliant grinding and polishing device, characterized in that: It comprises a robot body (001), a flexible connection device (002) and a grinding and polishing tool (003); The compliant connection device (002) comprises an upper connection flange (100), a magnetorheological damping unit (200), an electromagnetic variable stiffness unit (300), a support frame (400), a polishing connection flange (500), a force sensor (600) and a displacement sensor (700); The upper end of the magnetorheological damping unit (200) is connected to the upper connecting flange (100), and the lower end of the magnetorheological damping unit (200) is connected in series to the electromagnetic variable stiffness unit (300); The electromagnetic variable stiffness unit (300) is located inside the support frame (400), and the lower end of the electromagnetic variable stiffness unit (300) is connected to the grinding and polishing connection flange (500) through a force sensor (600); The upper end of the support frame (400) is connected to the magnetorheological damping unit (200), the lower end of the support frame (400) is connected to the polishing connection flange (500), and the displacement sensor (700) is fixed on the magnetorheological damping unit (200); The magnetorheological damping unit (200) is composed of a magnetic conductive ring (210), an upper end cover (220), an electromagnetic coil I (230), a magnetic isolation ring (240), a magnetorheological fluid (250), a magnetic fluid pressure plate (260), a guide rod (270) and a lower end cover (280); The electromagnetic coil I (230) is wound in the cavity of the magnetic isolation ring (240), a through hole I (241) is reserved at the lower end of the magnetic isolation ring for leading out a wire, the guide rod (270) is connected to the magnetic fluid pressure plate (260), the magnetic conductive ring (210) is connected to the upper end cover (220) and the lower end cover (280), the magnetorheological fluid (250) fills the area surrounded by the magnetic fluid pressure plate, the upper end cover (220), the lower end cover (280), and the magnetic isolation ring (240), wherein the upper end cover (220) is provided with a sealing groove I (221), the lower end cover (280) is provided with a sealing groove II (281) and a sealing groove III (282) for sealing the magnetorheological fluid (250), and the lower end of the lower end cover is provided with a through hole II (283) which cooperates with the through hole I (241) for leading out a wire in the electromagnetic coil I (230); The support frame (400) is composed of a support column (410), a guide rod (420), a support plate (430), a support spring (440), a linear bearing I (C01), and a linear bearing II (C02); The upper end of the support column (410) is connected to the lower end cover (280), and the lower end of the support column (410) is connected to the support plate (430). The middle and surrounding of the support plate (430) are provided with through holes IV (431) and V (432) for facilitating the insertion of the linear bearing I (C01) and the linear bearing II (C02). The support spring (440) is inserted into the guide rod (420), and the lower end of the guide rod (420) is provided with a threaded hole III (421) for matching with the grinding and polishing connection flange (500).

2. A robot compliant grinding and polishing device according to claim 1, characterized in that: The electromagnetic variable stiffness unit (300) is composed of an electromagnetic coil II (310), a magnetic isolation plate (320), an armature (330), and a permanent magnet (340); The electromagnetic coil II (310) is wound in a cavity connected to the armature (330) and the magnetic isolation plate (320); a through hole III (321) is reserved at the upper end of the magnetic isolation plate (320) for the guide rod (270) to pass through; the armature (330) is reserved with an internal thread (331) for matching with the external thread (271) of the guide rod (270); and the permanent magnet (340) is a hollow annular permanent magnet for easy insertion of the linear bearing I (C01).

3. A robot compliant grinding and polishing device according to claim 2, characterized in that: The grinding and polishing connection flange (500) is a "convex"-shaped flange with a raised truncated platform in the middle. A threaded hole I (510) is left in the middle of the raised platform of the grinding and polishing connection flange (500) for connection with the force sensor (600), and threaded holes II (520) and stepped holes (530) are left around it for matching with the grinding and polishing tool (003) and the guide rod (420).

4. A robot compliant grinding and polishing device according to claim 2, characterized in that: It also includes a displacement sensor fixing plate (710), the displacement sensor fixing plate (710) having a "T"-shaped plate shape, and a through hole VI (711) and a through hole VII (712) being left on the displacement sensor fixing plate (710).

5. The robot compliant grinding and polishing device according to claim 2, characterized in that: It also includes a displacement sensor reflective plate (720), the displacement sensor reflective plate (720) having a "Z" shape, a through hole VIII (721) for cooperating with the polishing connection flange (500), and a through hole IX (722) passing through the guide rod (420) for positioning.

6. A robot compliant grinding and polishing device according to claim 4, characterized in that: The guide rod (270) is in the form of a stepped rod with threads. An external thread (271) is left at the middle step of the guide rod (270). A threaded hole IV (272) is left at the upper end of the guide rod, and a threaded hole V (273) is left at the lower end.

7. The robot compliant grinding and polishing device according to claim 5, characterized in that: The support column (410) is in the shape of an I-shaped hollow column with symmetrical upper and lower ends and bidirectional cut edges, and threaded holes VI (411) are left at the upper and lower ends of the support column (410).

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