A three-degree-of-freedom parallel electromagnetic variable stiffness actuator for robot grinding and polishing end

Abstract

The present invention belongs to the technical field of mechanical transmission devices, and discloses a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of robot grinding and polishing. The present invention provides a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of robot grinding and polishing, and its necessary technical features include: a non-rigidity electromagnetic drive branch chain, whose drive motor is an electromagnetic direct drive motor module, and according to the force transmission characteristics, the force is completely compliant; three degrees of freedom movement can be generated through three non-rigidity electromagnetic drive branches; an electromagnetic spring drive branch chain, whose drive motor is an electromagnetic spring, which is responsible for providing adjustable stiffness; and a carefully designed structural component and peripheral sensor system for clever connection between structures and accurate force and displacement control. This comprehensive technical feature makes the actuator flexible, efficient and adaptable in the field of robotics technology.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical transmission devices, and in particular relates to a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for a robot grinding and polishing terminal. Background Art

[0002] For robot force-controlled end effectors in the field of contact operations, such as floating grinding equipment, the existing technology mostly uses single-degree-of-freedom mechanisms, which cannot meet the needs of high-precision polishing of complex surfaces; therefore, a three-degree-of-freedom parallel end force-controlled actuator that realizes two rotations and one movement has broad application prospects; the three-degree-of-freedom parallel mechanism or device has the advantages of good compactness and high load-bearing capacity, and therefore has been widely studied.

[0003] Traditional drive devices achieve the driving of objects through rigid design, that is, the transmission of motion and force through the "motor + reducer + load" method. This connection method cannot achieve smooth driving and does not have good environmental adaptability. When colliding with the environment, energy cannot be buffered and is stored. A certain degree of flexibility can be introduced through devices such as torsion springs.

[0004] Through the above analysis, the problems and defects of the prior art are as follows:

[0005] (1) The flexible introduction of devices such as torsion springs cannot change the rigid nature of the drive structure, and the rigidity of the end cannot be changed, which reduces the flexibility in scenarios with environmental changes.

[0006] (2) The existing parallel mechanism transmission and structure are complex and bulky, and the driving motor often needs to be driven by a motor + reducer. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for a robot grinding and polishing terminal.

[0008] The present invention is implemented in this way: a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for a robot grinding and polishing terminal comprises:

[0009] Non-rigidity electromagnetic drive branch chain, electromagnetic spring drive branch chain, and structural parts and peripheral sensor system;

[0010] There are three rigidity-free electromagnetic drive branches, namely, rigidity-free electromagnetic drive branch 1, rigidity-free electromagnetic drive branch 2 and rigidity-free electromagnetic drive branch 3; one end of the rigidity-free electromagnetic drive branch is directly connected to the end motion plate, and the other end is connected to the robot end consolidation plate; the three rigidity-free branches of the same structure are evenly distributed along the circumference of the actuator center axis.

[0011] Furthermore, the electromagnetic spring driven branch chain is located at the central axis of the actuator, one end of the branch chain is directly connected to the end motion plate, and the other end is connected to the robot end consolidation plate.

[0012] Furthermore, the electromagnetic spring drive branch chain and the three non-rigidity electromagnetic drive branch chains are all connected to the end motion plate and the robot end consolidation plate to form a parallel transmission form.

[0013] Furthermore, the rigidity-free electromagnetic drive branch chain includes an electromagnetic direct drive motor module, a preloaded rigidity spring, a linear bearing, a support connector 1, a support connector 2, a linear bearing guide rail, a universal joint at the proximal motor end, a universal joint at the distal motor end, and a rigidity-free electromagnetic drive connecting rod.

[0014] Furthermore, the transmission process of the rigidity-free electromagnetic drive branch chain is as follows: the electromagnetic direct-drive motor module generates a driving force, which passes through the support connector 1 and moves linearly along the linear bearing guide rail. The linear motion is transmitted to the end motion plate through the universal joint at the near motor end, the rigidity-free electromagnetic drive connecting rod, and the universal joint at the far motor end; three rigidity-free electromagnetic drive branch chains with the same transmission route act on the end motion plate together, and the end motion plate generates two rotations and one translational motion.

[0015] Furthermore, the electromagnetic direct-drive motor module consists of a ferromagnetic yoke plate, a square permanent magnet, a coil support plate, a permanent magnet yoke plate support plate and a square coil.

[0016] Furthermore, the linear bearing guide rail is equipped with four preload stiffness springs.

[0017] Further, the electromagnetic spring driven branch chain includes an electromagnetic spring module, a circular permanent magnet bracket-connecting rod, a double-headed ball valve, a ball valve connecting rod, and a single-headed ball valve;

[0018] The stiffness transfer process of the electromagnetic spring driven branch chain is that the electromagnetic spring module generates variable stiffness, which is transferred to the end motion plate through the circular permanent magnet bracket-connecting rod, the double-headed ball valve, the ball valve connecting rod, and the single-headed ball valve; the use of the double-headed ball valve and the single-throw ball valve prevents the introduction of variable stiffness from constraining the freedom of the end motion plate.

[0019] Furthermore, the electromagnetic spring module includes a circular permanent magnet and a circular coil. The magnetic field generated by the circular coil is related to the position to form a non-uniformly distributed magnetic field along the axis. The magnetic fields generated by the circular permanent magnet and the circular coil interact to generate stiffness.

[0020] Furthermore, the structural parts and peripheral sensor system include a main shaft, a main shaft fixture, a rigidity-free electromagnetic drive branch chain integrated fixing plate, a robot end consolidation plate, an end motion plate, a force sensor, and a grating ruler displacement sensor;

[0021] The force sensor and the displacement sensor feedback can realize precise force control and displacement control;

[0022] The spindle, spindle fixture, non-rigidity electromagnetic drive branch chain integrated fixing plate, robot end consolidation plate, and end motion plate can realize the end fixation and processing of the robot.

[0023] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0024] First, the present invention designs a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of robot grinding and polishing, the stiffness of which can be configured in real time by controlling the current of the electromagnetic spring. The stiffness directly acts on the end of the motion, improving the applicability of the actuator and providing better processing performance when processing complex parts;

[0025] The present invention designs a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the robot grinding and polishing end. The three degrees of freedom are directly generated through electromagnetic direct-drive motor transmission. Compared with the traditional three-degree-of-freedom parallel mechanism, it has high response, low latency, and high compliance actuator performance, and can provide higher force control and posture control accuracy.

[0026] The present invention designs a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of a robot grinding and polishing machine. The three-degree-of-freedom drive is realized by an electromagnetic direct-drive motor, the end stiffness is realized by an electromagnetic spring, and the stiffness transmission branch is separated and decoupled from the motion branch, thereby realizing decoupling control of three-degree-of-freedom motion and stiffness and reducing control costs.

[0027] The present invention designs a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of robot grinding and polishing, which introduces a rigid electromagnetic drive chain and improves the traditional drive chain into a non-rigid electromagnetic drive chain. The entire actuator is effectively integrated through ingenious circular symmetry design and structural design.

[0028] Ultimately, the technical solution of the present invention solves a technical problem that people have always been eager to solve but have never succeeded in solving: it solves the following problems for the high-precision and compliant processing technology of complex surfaces of robots: precise stiffness adjustment and force control, compliant and high-precision posture adjustment, and high-response, low-latency actuator performance.

[0029] The core of the technical solution of the present invention is to develop a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of robot grinding and polishing, and its necessary technical features include: a non-rigid electromagnetic drive branch chain, whose drive motor is an electromagnetic direct drive motor module, and according to the force transmission characteristics, the force is completely compliant; three degrees of freedom movement can be generated through three non-rigid electromagnetic drive branches; an electromagnetic spring drive branch chain, whose drive motor is an electromagnetic spring, which is responsible for providing adjustable stiffness; and a carefully designed structural component and peripheral sensor system for clever connection between structures and accurate force and displacement control. This comprehensive technical feature makes the actuator flexible, efficient and adaptable in the field of robotics.

[0030] The present invention is implemented as follows: a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of a robot grinding and polishing, characterized by a non-rigidity electromagnetic drive branch chain, an electromagnetic spring drive branch chain, and a structural part and a peripheral sensor system.

[0031] Second, the expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0032] Improve processing efficiency and precision: In high-precision polishing operations, robots can complete tasks faster and more accurately, reducing manual intervention and error rates. Reduce maintenance costs: By using non-rigidity electromagnetic drives and electromagnetic springs, the wear and failure rate of traditional rigid drive systems is reduced, extending the service life of the equipment. Broaden the application field: This technology is not only suitable for robot polishing operations, but can also be extended to other fields that require high-precision force control, such as medical surgical robots, precision assembly, etc.

[0033] The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0034] The current market lacks robot end effectors that can achieve both high-precision force control and adjustable stiffness. Traditional single-degree-of-freedom mechanisms and rigid drive methods cannot meet the high-precision polishing requirements of complex surfaces. The present invention fills this technical gap by introducing a three-degree-of-freedom parallel electromagnetic variable stiffness actuator, providing a brand-new solution that is expected to be widely used and recognized in the domestic and international markets.

[0035] The technical solution of the present invention solves the technical problems that people have been eager to solve but have never been able to solve successfully:

[0036] The invention solves the problem that traditional drive devices cannot achieve compliant driving. It realizes high-precision force control and posture control, and realizes real-time adjustment of stiffness through the introduction of electromagnetic springs. This technological breakthrough is of great significance in the scenes of robot complex surface polishing, high-precision processing and high compliance requirements, and solves the problem of balancing high precision and compliance that has long plagued the industry.

[0037] The technical solution of the present invention overcomes technical prejudice:

[0038] The present invention overcomes the technical prejudice of rigid design and complex transmission structure in traditional mechanical transmission devices through the innovative design of non-rigid electromagnetic drive branch chain and electromagnetic spring drive branch chain. The traditional view is that high precision and flexibility are difficult to take into account at the same time, but the present invention achieves high-precision, low-latency, and high-flexibility actuator performance through clever design and technological innovation, breaking through this technical prejudice and creating a new direction for robot force-controlled end effectors.

[0039] Third, the present invention proposes a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the robot grinding and polishing end, which has a unique and innovative design, effectively solves multiple problems in the prior art, and has achieved significant technological progress.

[0040] First, the actuator achieves high-precision and high-flexibility control of the grinding and polishing end through a unique three-degree-of-freedom parallel structure. This design enables the actuator to move and rotate freely in multiple directions, thereby more accurately adapting to the complex shapes and contours of the workpiece surface, improving the quality and efficiency of the grinding and polishing operation.

[0041] Secondly, the parallel transmission form of the electromagnetic spring drive branch chain and the non-rigidity electromagnetic drive branch chain in the present invention provides a rich range of stiffness changes for the actuator. This design enables the actuator to adjust its stiffness in real time according to the operation requirements, thereby effectively coping with the changes of different workpiece materials and grinding and polishing forces while maintaining high precision, thereby improving the stability and reliability of the operation.

[0042] In addition, the innovative design of the non-rigid electromagnetic drive branch chain is also a highlight of the present invention. The branch chain achieves high-precision, non-rigid drive of the end motion plate through the ingenious combination of electromagnetic direct drive motor module, preloaded stiffness spring, linear bearing and other components. This design not only reduces the complexity and cost of the actuator, but also improves its response speed and accuracy.

[0043] In summary, the present invention successfully solves many technical problems of the end effector of the existing grinding and polishing robot through a unique three-degree-of-freedom parallel structure, a rich range of stiffness variations, and an innovative non-rigid electromagnetic drive branch chain design. The implementation of the present invention will significantly improve the accuracy, efficiency, and stability of grinding and polishing operations, and inject new vitality into the development of industrial automation and intelligent manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a detailed structural schematic diagram of the non-rigidity electromagnetic drive branch chain provided in an embodiment of the present invention.

[0045] Figure 2 It is a schematic diagram of the principle of the three-degree-of-freedom parallel branched chain structure provided by an embodiment of the present invention.

[0046] Figure 3 It is a schematic diagram of the distribution of a three-degree-of-freedom parallel branched chain structure provided in an embodiment of the present invention.

[0047] Figure 4 It is a schematic diagram of the structure of an electromagnetic direct drive module provided in an embodiment of the present invention.

[0048] Figure 5 It is a schematic diagram of a complementary supporting connector provided in an embodiment of the present invention.

[0049] Figure 6 It is a schematic diagram of the structure of an electromagnetic spring provided by an embodiment of the present invention.

[0050] Figure 7 It is a schematic diagram of the detailed structure of the electromagnetic spring driven branch chain provided in an embodiment of the present invention.

[0051] Figure 8 It is a schematic diagram of the three-view and axial side view of the three-degree-of-freedom parallel electromagnetic variable stiffness actuator at the robot grinding and polishing terminal provided by an embodiment of the present invention.

[0052] In the figure: 101, ferromagnetic yoke plate; 102, square permanent magnet; 103, coil support plate; 104, permanent magnet yoke support plate; 105, square coil; 201, circular permanent magnet bracket-connecting rod; 202, circular permanent magnet; 203, circular coil; 301, remote motor end universal joint; 302, non-rigid electromagnetic drive connecting rod; 303, preload stiffness spring 304, linear bearing; 305, support connection Part 1; 306, universal joint near the motor end; 307, support connector 2; 308, linear bearing guide; 309, double-headed ball valve; 310, ball valve connecting rod; 311, single-headed ball valve; 401, main shaft; 402, main shaft fixture; 403, rigidity-free electromagnetic drive branch chain integrated fixing plate; 404, robot end consolidation plate; 405, end motion plate; 406, force sensor; 407, grating scale displacement sensor. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] Example 1: Surface grinding of smartphone housing

[0055] Smartphone casings are usually made of materials such as aluminum alloy, stainless steel or glass, and require fine surface grinding to ensure a smooth, flawless surface with good feel and appearance quality.

[0056] 1) Installation and configuration:

[0057] Three stiffness-free electromagnetic drive branches and an electromagnetic spring drive branch chain are installed on the end of the smartphone casing grinding robot.

[0058] Ensure that each non-rigid electromagnetic drive branch chain is evenly distributed on the circumference of the actuator center axis and connected to the end motion plate and the robot end consolidation plate.

[0059] 2) Force control and stiffness adjustment:

[0060] According to the hardness of the smartphone shell material, an electromagnetic direct-drive motor module and a preloaded stiffness spring are used to adjust the stiffness of the non-stiffness electromagnetic drive branch chain to meet the grinding requirements of different materials.

[0061] During the grinding process, the sensor system monitors the grinding force and displacement in real time, and dynamically adjusts the stiffness of the electromagnetic spring-driven branch chain to ensure that the surface grinding force is uniform and stable.

[0062] 3) High precision grinding:

[0063] By controlling the position and motion trajectory of the end motion plate, the robot can accurately follow the surface shape of the smartphone case for grinding.

[0064] The non-rigid electromagnetic drive branch chain provides flexible movement and force control, allowing the robot to adapt to complex curved surface structures and ensure the consistency and high quality of the grinding effect.

[0065] By using a three-degree-of-freedom parallel electromagnetic variable stiffness actuator, the surface grinding process of smartphone casings has become more efficient and precise, the surface quality has been significantly improved, scratches and blemishes have been reduced, and the overall appearance and user experience of the product have been improved.

[0066] Example 2: Polishing the inner wall of automobile engine cylinder

[0067] The inner wall of the automobile engine cylinder needs to be polished with high precision to reduce friction and improve engine performance and service life. The inner wall of the cylinder has complex geometry and high processing precision requirements, which are difficult to meet with traditional polishing methods.

[0068] 1) Installation and configuration:

[0069] Three non-rigidity electromagnetic driven branch chains and an electromagnetic spring driven branch chain are installed on the end of a robot used for polishing the inner wall of an engine cylinder.

[0070] Ensure that the three non-rigid electromagnetic drive branches are evenly distributed along the circumference of the actuator center axis and connected to the end motion plate and the robot end consolidation plate.

[0071] 2) Force control and stiffness adjustment:

[0072] According to the material and structural characteristics of the inner wall of the engine cylinder, the electromagnetic direct drive motor module and the preload stiffness spring are used to adjust the stiffness of the non-stiffness electromagnetic drive branch chain.

[0073] During the polishing process, the polishing force and displacement are monitored in real time through the sensor system, and the stiffness of the electromagnetic spring-driven branch chain is dynamically adjusted to adapt to the complex shape of the inner wall of the cylinder and the stiffness changes in different parts.

[0074] 3) High precision polishing:

[0075] By controlling the position and motion trajectory of the end motion plate, the robot can accurately follow the complex geometry of the inner wall of the engine cylinder for polishing.

[0076] The rigidity-free electromagnetic drive branch chain provides flexible movement and force control, allowing the robot to adapt to the curved surface structure of the cylinder wall, ensuring the consistency and high quality of the polishing effect.

[0077] By using a three-degree-of-freedom parallel electromagnetic variable stiffness actuator, the polishing process of the inner wall of the engine cylinder becomes more efficient and precise, the surface finish of the inner wall is significantly improved, friction is reduced, the service life of the engine is extended, and the performance and reliability of the engine are improved.

[0078] The above two specific embodiments demonstrate the application of the actuator in the surface grinding of smartphone casings and the polishing of the inner wall of automobile engine cylinders. Through high-precision force control and stiffness adjustment, high-quality grinding and polishing effects of complex surfaces are achieved.

[0079] The core of the technical solution of the present invention is to develop a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of robot grinding and polishing, and its necessary technical features include: a non-rigid electromagnetic drive branch chain, whose drive motor is an electromagnetic direct drive motor module, and according to the force transmission characteristics, the force is completely compliant; three degrees of freedom movement can be generated through three non-rigid electromagnetic drive branches; an electromagnetic spring drive branch chain, whose drive motor is an electromagnetic spring, which is responsible for providing adjustable stiffness; and a carefully designed structural component and peripheral sensor system for clever connection between structures and accurate force and displacement control. This comprehensive technical feature makes the actuator flexible, efficient and adaptable in the field of robotics.

[0080] The present invention is implemented as follows: a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of a robot grinding and polishing, characterized by a non-rigidity electromagnetic drive branch chain, an electromagnetic spring drive branch chain, and a structural part and a peripheral sensor system.

[0081] like Figure 1-8As shown, the embodiment of the present invention provides three rigidity-free electromagnetic drive branches, namely, rigidity-free electromagnetic drive branch 1, rigidity-free electromagnetic drive branch 2 and rigidity-free electromagnetic drive branch 3; one end of the rigidity-free electromagnetic drive branch is directly connected to the end motion plate 405, and the other end is connected to the robot end consolidation plate 404; the three rigidity-free branches of the same structure are evenly distributed along the circumference of the actuator center axis.

[0082] In order to integrate and reduce the volume of the actuator and ensure the transmission of stiffness, the embodiment of the present invention provides an electromagnetic spring drive branch chain located at the central axis of the actuator, one end of the branch chain is directly connected to the end motion plate 405, and the other end is connected to the robot end consolidation plate 404.

[0083] The electromagnetic spring drive branch chain and the three non-rigidity electromagnetic drive branch chains provided in the embodiment of the present invention are all connected to the end motion plate 405 and the robot end consolidation plate 404 to form a parallel transmission form.

[0084] The non-rigidity electromagnetic drive branch chain includes an electromagnetic direct drive motor module, a preloaded stiffness spring 303, a linear bearing 304, a support connector 1305, a support connector 2307, a linear bearing guide rail 308, a near motor end universal joint 306, a far motor end universal joint 301, and a non-rigidity electromagnetic drive connecting rod 302.

[0085] The transmission process of the non-rigidity electromagnetic drive branch chain provided by the embodiment of the present invention is that the electromagnetic direct drive motor module generates a driving force, and the linear motion along the linear bearing guide rail 309 passes through the support connector 1305, and the linear motion is transmitted to the terminal motion plate 405 through the near motor end universal joint 306, the non-rigidity electromagnetic drive connecting rod 302, and the far motor end universal joint 301. Three non-rigidity electromagnetic drive branch chains with the same transmission route act together on the terminal motion plate 405, and the terminal motion plate 405 can generate two rotations and one translation motion.

[0086] The electromagnetic direct-drive motor module provided in the embodiment of the present invention comprises a ferromagnetic yoke plate 101 , a square permanent magnet 102 , a coil support plate 103 , a permanent magnet yoke plate support plate 104 and a square coil 105 .

[0087] In order to balance the uniform transmission force of the electromagnetic direct-drive motor module in the rigidity-free electromagnetic drive branch chain and ensure the stable displacement of the support plate 104 and the square coil 105, the embodiment of the present invention provides that each coil support plate 103 is supported by the support connector 1305 and the support connector 2307 at the same time during transmission, and moves along the linear bearing guide rail 309 through the linear bearing 304.

[0088] In order to integrate and reduce the volume of the actuator, the embodiment of the present invention provides that each linear bearing guide rail 309 has a support connector 1305 of a different non-rigidity electromagnetic drive branch chain and a support connector 2307 of another non-rigidity electromagnetic drive branch chain.

[0089] In order to ensure that the support connector 1305 and the support connector 2307 on a linear bearing guide rail 309 do not interfere with each other during the movement of the electromagnetic direct drive motor, the embodiment of the present invention needs to be designed as complementary shapes and reserve travel displacement.

[0090] The linear bearing guide rail 309 provided in the embodiment of the present invention is installed with four preloaded stiffness springs 303 to ensure that there is no collision of the stiffness electromagnetic drive branch chain when it is not driven.

[0091] The electromagnetic spring driven branch chain includes an electromagnetic spring module, a circular permanent magnet bracket-connecting rod 201 , a double-headed ball valve 309 , a ball valve connecting rod 310 , and a single-headed ball valve 311 .

[0092] The stiffness transmission process of the electromagnetic spring driven branch chain provided in the embodiment of the present invention is that the electromagnetic spring module generates variable stiffness, which is transmitted to the end motion plate 405 through the circular permanent magnet bracket-connecting rod 201, the double-headed ball valve 309, the ball valve connecting rod 310, and the single-headed ball valve 311. The use of the double-headed ball valve 309 and the single-throw ball valve 311 prevents the introduction of variable stiffness from constraining the degree of freedom of the end motion plate 405.

[0093] The electromagnetic spring module provided by the embodiment of the present invention includes a circular permanent magnet 202 and a circular coil 203. The magnetic field generated by the circular coil is position-dependent to form a non-uniformly distributed magnetic field along the axis. The magnetic fields generated by the circular permanent magnet and the circular coil interact to generate stiffness.

[0094] In order to ensure that the rigidity generated by the circular permanent magnet 202 is transmitted by the cylindrical support component 204, the embodiment of the present invention combines the cylindrical support component 204 with the circular permanent magnet support-connecting rod 201 to encapsulate the circular permanent magnet 202 inside the cylindrical support component 204.

[0095] In a non-rigid electromagnetic drive branch chain provided by an embodiment of the present invention, in the initial position, the universal joint 306 near the motor end has two rotating shafts S3 and S4, the rotating shaft S1 connected to the electromagnetic direct drive motor module needs to be parallel to the z-axis, and the rotating shaft S2 connected to the non-rigid electromagnetic drive connecting rod 302 needs to be parallel to the y-axis. In the non-rigid electromagnetic drive branch chain, the linear motion of the position S1 is generated by the electromagnetic direct drive motor module, rather than the traditional motor screw transmission.

[0096] In a non-rigidity electromagnetic drive branch chain provided by an embodiment of the present invention, in the initial position, the universal joint 301 at the far motor end has two rotating shafts S3 and S4, the rotating shaft S3 connected to the non-rigidity electromagnetic drive connecting rod 302 needs to be parallel to the y-axis, and the rotating shaft S4 connected to the end motion plate 405 needs to be parallel to the x-axis.

[0097] The initial position of the actuator provided by the embodiment of the present invention is defined as: the end motion plate 405 is parallel to the robot end consolidation plate 404, and the ball valve connecting rod 310 is perpendicular to the position where the end motion plate 405 is parallel to the robot end consolidation plate 404.

[0098] The structural parts and peripheral sensor system include a main shaft 401, a main shaft fixture 402, a rigidity-free electromagnetic drive branch chain integrated fixing plate 403, a robot end consolidation plate 404, an end motion plate 405, a force sensor 406, and a grating scale displacement sensor 407.

[0099] The embodiment of the present invention provides that precise force control and displacement control can be achieved through feedback from the force sensor and the displacement sensor;

[0100] The embodiment of the present invention provides a main shaft 401, a main shaft fixture 402, a rigidity-free electromagnetic drive branch chain integrated fixing plate 403, a robot end consolidation plate 404, and an end motion plate 405 to achieve end fixation and processing with the robot.

[0101] Another object of the present invention is to provide a method for a three-degree-of-freedom parallel electromagnetic variable stiffness actuator at the end of a robot grinding and polishing, comprising:

[0102] Step 1: Use the electromagnetic direct drive module to generate direct drive force, which is flexible rather than rigid;

[0103] Step 2: Build three parallel non-rigid electromagnetic drive branches, and use the electromagnetic direct drive module to generate direct drive force to achieve three-degree-of-freedom motion of the actuator

[0104] Step 3: construct an electromagnetic spring drive branch chain directly connected in parallel with the end to generate stiffness to adapt to different operating environments and mission requirements;

[0105] Step 4: Achieve precision through sensor system

[0106] Precise control, using sensor systems to monitor and control force and displacement;

[0107] Step 5: Based on the characteristics of the branch chain, a specific branch chain layout is adopted to effectively realize the three-degree-of-freedom motion while introducing the stiffness control of the end;

[0108] Step 6: Through structural design, the overall structure of the actuator is effectively integrated to ensure the function and stability of the actuator while effectively reducing the size of the actuator;

[0109] The present invention is specifically implemented:

[0110] The core of the technical solution of the present invention is to develop a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of robot grinding and polishing, and its necessary technical features include: a non-rigid electromagnetic drive branch chain, whose drive motor is an electromagnetic direct drive motor module, and according to the force transmission characteristics, the force is completely compliant; three degrees of freedom movement can be generated through three non-rigid electromagnetic drive branches; an electromagnetic spring drive branch chain, whose drive motor is an electromagnetic spring, which is responsible for providing adjustable stiffness; and a carefully designed structural component and peripheral sensor system for clever connection between structures and accurate force and displacement control. This comprehensive technical feature makes the actuator flexible, efficient and adaptable in the field of robotics.

[0111] The present invention is implemented as follows: a three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the end of a robot grinding and polishing, characterized by a non-rigidity electromagnetic drive branch chain, an electromagnetic spring drive branch chain, and a structural part and a peripheral sensor system.

[0112] The overall link distribution is as follows:

[0113] The branch chain refers to the entire link from the drive generation module to the actuator module, such as Figure 3 As shown, a three-degree-of-freedom parallel electromagnetic variable stiffness actuator at the end of a robot is provided, wherein there are three stiffness-free electromagnetic drive branches, namely, stiffness-free electromagnetic drive branch 1, stiffness-free electromagnetic drive branch 2 and stiffness-free electromagnetic drive branch 3; one end of the stiffness-free electromagnetic drive branch is directly connected to the end motion plate 405, and the other end is connected to the robot end consolidation plate 404; the three stiffness-free branches of the same structure are evenly distributed along the circumference of the actuator center axis.

[0114] like Figure 3 As shown, in order to integrate and reduce the volume of the actuator and ensure the transmission of stiffness, an electromagnetic spring driven branch chain is designed to be located at the central axis of the actuator, one end of the branch chain is directly connected to the end motion plate 405, and the other end is connected to the robot end consolidation plate 404.

[0115] like Figure 2 As shown, the electromagnetic spring drive branch chain and the three non-rigid electromagnetic drive branch chains are connected to the end motion plate 405 and the robot end consolidation plate 404 to form a parallel transmission form. Since the three non-rigid electromagnetic drive branch chains are evenly distributed on the circumference and the axis is the electromagnetic spring drive branch chain shown in the figure, as shown Figure 2 Only one stiffness-free electromagnetic drive branch is shown schematically.

[0116] like Figure 2As shown, in a non-rigid electromagnetic drive branch chain, in the initial position, the universal joint 306 near the motor end has two rotating shafts S3 and S4, the rotating shaft S1 connected to the electromagnetic direct drive motor module needs to be parallel to the z-axis, and the rotating shaft S2 connected to the non-rigid electromagnetic drive connecting rod 302 needs to be parallel to the y-axis. It is particularly important to note that the linear motion of the position S1 in the non-rigid electromagnetic drive branch chain is achieved by the electromagnetic direct drive motor module, rather than the traditional motor screw transmission.

[0117] like Figure 2 As shown, in a rigid electromagnetic drive branch chain, in the initial position, the universal joint 301 at the far motor end has two rotating shafts S3 and S4. The rotating shaft S3 connected to the rigid electromagnetic drive connecting rod 302 needs to be parallel to the y-axis, and the rotating shaft S4 connected to the end motion plate 405 needs to be parallel to the x-axis.

[0118] The three non-rigidity electromagnetic drive branches are constructed as follows:

[0119] like Figure 1 As shown, the rigidity-free electromagnetic drive branch chain includes an electromagnetic direct drive motor module, a preloaded stiffness spring 303, a linear bearing 304, a support connector 1305, a support connector 2307, a linear bearing guide 308, a near-motor end universal joint 306, a far-motor end universal joint 301, and a rigidity-free electromagnetic drive connecting rod 302.

[0120] Combination Figure 2 and Figure 1 The transmission process of the non-rigid electromagnetic drive branch chain is that the electromagnetic direct drive motor module generates a driving force, which moves linearly along the linear bearing guide rail 309 through the support connector 1305, and the linear motion is transmitted to the end motion plate 405 through the near motor end universal joint 306, the non-rigid electromagnetic drive connecting rod 302, and the far motor end universal joint 301. The three non-rigid electromagnetic drive branch chains with the same transmission route act together on the end motion plate 405, and the end motion plate 405 can generate two rotations and one translation motion.

[0121] The electromagnetic direct drive motor module consists of a ferromagnetic yoke plate 101, a square permanent magnet 102, a coil support plate 103, a permanent magnet yoke plate support plate 104 and a square coil 105. The structure is to provide electromagnetic direct drive force without the need for rotational transmission.

[0122] like Figure 2 As shown, in order to balance the uniform transmission force of the electromagnetic direct-drive motor module in the rigidity-free electromagnetic drive branch and ensure the stable displacement of the support plate 104 and the square coil 105, each coil support plate 103 is supported by the support connector 1305 and the support connector 2307 at the same time during transmission, and moves along the linear bearing guide 309 through the linear bearing 304.

[0123] like Figure 2 As shown, in order to integrate and reduce the volume of the actuator, each linear bearing guide rail 308 has a support connector 1305 of a different non-rigidity electromagnetic drive branch chain and a support connector 2307 of another non-rigidity electromagnetic drive branch chain.

[0124] like Figure 1 and Figure 3 As shown, in order to ensure that the support connector 1305 and the support connector 2307 on a linear bearing guide rail 308 do not interfere with each other during the movement of the electromagnetic direct drive motor;

[0125] like Figure 4 As shown, the support connector 1305 and the support connector 2307 need to be designed as complementary shapes and reserve travel displacement.

[0126] like Figure 3 As shown, the linear bearing guide rail 308 is installed with four preloaded stiffness springs 303 to ensure that there is no collision of the stiffness electromagnetic drive branch chain when it is not driven.

[0127] The electromagnetic spring driven branch chain is constructed as follows:

[0128] like Figure 5 and Figure 6 As shown, the electromagnetic spring drive branch chain includes an electromagnetic spring module, a circular permanent magnet bracket-connecting rod 201, a double-headed ball valve 309, a ball valve connecting rod 310, and a single-headed ball valve 311.

[0129] like Figure 6 As shown, the stiffness transmission process of the electromagnetic spring driven branch chain is that the electromagnetic spring module generates variable stiffness, which is transmitted to the end motion plate 405 through the circular permanent magnet bracket-connecting rod 201, the double-headed ball valve 309, the ball valve connecting rod 310, and the single-headed ball valve 311. The use of the double-headed ball valve 309 and the single-throw ball valve 311 prevents the introduction of variable stiffness from constraining the freedom of the end motion plate 405.

[0130] like Figure 5 As shown, the electromagnetic spring module includes a circular permanent magnet 202 and a circular coil 203. The magnetic field generated by the circular coil is position-dependent to form a non-uniformly distributed magnetic field along the axis. The magnetic fields generated by the circular permanent magnet and the circular coil interact to generate stiffness.

[0131] like Figure 5 As shown, in order to ensure that the stiffness generated by the circular permanent magnet 202 is transmitted by the cylindrical support member 204, the cylindrical support member 204 and the circular permanent magnet support-connecting rod 201 are combined to encapsulate the circular permanent magnet 202 inside the cylindrical support member 204 and the circular permanent magnet support-connecting rod 201.

[0132] like Figure 7As shown, the initial position of the actuator is defined as: the end motion plate 405 is parallel to the robot end consolidation plate 404, and the ball valve connecting rod 310 is perpendicular to the position where the end motion plate 405 is parallel to the robot end consolidation plate 404.

[0133] like Figure 8 As shown, the structural parts and peripheral sensor system include a spindle 401, a spindle fixture 402, a rigid electromagnetic drive branch chain integrated fixing plate 403, a robot end consolidation plate 404, an end motion plate 405, a force sensor 406, and a grating ruler displacement sensor 407. Precise force control and displacement control can be achieved through the feedback of the force sensor and the displacement sensor; the end fixation and processing of the robot can be achieved through the spindle 401, the spindle fixture 402, the rigid electromagnetic drive branch chain integrated fixing plate 403, the robot end consolidation plate 404, and the end motion plate 405.

[0134] 1. Specific application fields or related products of the present invention.

[0135] Complex surface high-precision polishing field: complex surface parts polishing in the aerospace industry; body and engine parts polishing in the automotive manufacturing industry; high-precision surface treatment in mold manufacturing.

[0136] Precision machining and assembly fields: assembly and debugging of precision instruments and equipment; precision welding and assembly in the electronics manufacturing industry; high-precision machining in medical equipment manufacturing.

[0137] Medical surgical robots: operations that require high precision and flexibility during surgery, such as minimally invasive surgical robots; rehabilitation robots, used for precise rehabilitation training and assistance.

[0138] Scientific research and education: experimental platforms in robotics and control engineering research; teaching and research equipment in universities and research institutions.

[0139] Industrial automation: high-precision force control operations in flexible manufacturing systems; precision assembly and testing in automated production lines.

[0140] 2. Relevant evidence of the technical effects obtained by the embodiments of the present invention.

[0141] Precise stiffness adjustment and force control: Real-time stiffness adjustment is achieved through current control of electromagnetic springs, which can adapt to different processing environments and materials. Precise force control and displacement control are achieved using force sensor and displacement sensor feedback.

[0142] High flexibility and adaptability: The non-rigid electromagnetic drive branch chain ensures flexibility during movement and can adapt to the polishing needs of complex curved surfaces. The electromagnetic variable stiffness technology provides higher environmental adaptability and operational flexibility.

[0143] High-response, low-latency actuator performance: The electromagnetic direct-drive motor module achieves fast response and low-latency drive control, improving the dynamic performance of the actuator. The three-degree-of-freedom parallel structure design provides an efficient motion and force transmission path, further improving the performance of the actuator.

[0144] Reduce control cost and complexity: The stiffness transmission branch chain is separated and decoupled from the motion branch chain, realizing independent control of three-degree-of-freedom motion and stiffness, simplifying the control system design. The modular design makes system maintenance and upgrades more convenient and reduces overall costs.

[0145] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0146] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A three-degree-of-freedom parallel electromagnetic variable stiffness actuator for robot grinding and polishing end, characterized in that: include: Non-rigidity electromagnetic drive branch chain, electromagnetic spring drive branch chain, and structural parts and peripheral sensor system; There are three rigidity-free electromagnetic drive branches, namely, rigidity-free electromagnetic drive branch 1, rigidity-free electromagnetic drive branch 2 and rigidity-free electromagnetic drive branch 3; one end of the rigidity-free electromagnetic drive branch is directly connected to the end motion plate, and the other end is connected to the robot end consolidation plate; the three rigidity-free branches of the same structure are evenly distributed along the circumference of the actuator center axis; The electromagnetic spring driven branch chain is located at the central axis of the actuator, one end of the branch chain is directly connected to the end motion plate, and the other end is connected to the robot end consolidation plate; The electromagnetic spring drive branch chain and the three non-rigid electromagnetic drive branch chains are all connected to the end motion plate and the robot end consolidation plate to form a parallel transmission form; The non-rigidity electromagnetic drive branch chain includes an electromagnetic direct drive motor module, a preloaded stiffness spring, a linear bearing, a support connector 1, a support connector 2, a linear bearing guide rail, a universal joint at a near motor end, a universal joint at a far motor end, and a non-rigidity electromagnetic drive connecting rod; The transmission process of the non-rigidity electromagnetic drive branch chain is as follows: the electromagnetic direct drive motor module generates a driving force, which moves linearly along the linear bearing guide rail through the support connector 1, and the linear motion is transmitted to the end motion plate through the universal joint at the near motor end, the non-rigidity electromagnetic drive connecting rod, and the universal joint at the far motor end; three non-rigidity electromagnetic drive branch chains with the same transmission route act on the end motion plate together, and the end motion plate generates two rotations and one translation motion; The electromagnetic spring driven branch chain includes an electromagnetic spring module, a circular permanent magnet bracket-connecting rod, a double-headed ball valve, a ball valve connecting rod, and a single-headed ball valve; The stiffness transfer process of the electromagnetic spring driven branch chain is that the electromagnetic spring module generates variable stiffness, which is transferred to the end motion plate through the circular permanent magnet bracket-connecting rod, the double-headed ball valve, the ball valve connecting rod, and the single-headed ball valve; the use of the double-headed ball valve and the single-throw ball valve prevents the introduction of variable stiffness from constraining the freedom of the end motion plate.

2. The three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the robot polishing terminal as claimed in claim 1, characterized in that: The electromagnetic direct-drive motor module comprises a ferromagnetic yoke plate, a square permanent magnet, a coil support plate, a permanent magnet yoke plate support plate and a square coil.

3. The three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the robot polishing terminal as claimed in claim 1, characterized in that: The linear bearing guide rail is equipped with 4 preload stiffness springs.

4. The three-degree-of-freedom parallel electromagnetic variable stiffness actuator for the robot polishing terminal as claimed in claim 1, characterized in that: The electromagnetic spring module comprises a circular permanent magnet and a circular coil. The magnetic field generated by the circular coil is related to the position to form a non-uniformly distributed magnetic field along the axis. The magnetic fields generated by the circular permanent magnet and the circular coil interact to generate stiffness.

5. The three-degree-of-freedom parallel electromagnetic variable stiffness actuator for robot polishing terminal as claimed in claim 1, characterized in that: The structural parts and peripheral sensor system include a spindle, a spindle fixture, a rigidity-free electromagnetic drive branch chain integrated fixing plate, a robot end consolidation plate, an end motion plate, a force sensor, and a grating ruler displacement sensor; The force sensor and the displacement sensor feedback realize precise force control and displacement control; The spindle, spindle fixture, non-rigidity electromagnetic drive branch chain integrated fixing plate, robot end consolidation plate, and end motion plate realize the end fixation and processing of the robot.

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