Active compliant transmission joint based on magnetic field regulation and working method

Abstract

The application discloses a kind of active compliant transmission joint based on magnetic field regulation and working method, including output module, rigidity adjusting module, position driving module.The application uses magnetic coupling technology to realize variable stiffness transmission, since there is no physical contact in transmission process, therefore there is no friction loss, which makes the life of non-contact transmission system longer, improves the stability of the whole joint;Gear rack mechanism is used to realize the first-stage stiffness adjustment of the joint, at the same time, the cam and gear integrated structure is used to realize the change of magnetic coupling gap, and the spiral chute is used to realize the radial position change of the sector yoke module, to realize the synchronous performance of second-stage stiffness adjustment;It can dynamically and quickly adjust its response characteristics according to external load, and the multi-stage stiffness adjustment increases the stiffness adjustment range of the joint, so as to maintain better adaptability in working environment.

Description

Technical Field

[0001] This invention relates to a transmission joint, specifically an active compliant transmission joint based on magnetic field control and its working method, belonging to the field of robot control technology. Background Technology

[0002] The booming robotics industry is profoundly changing human production and lifestyles. With its rise and development, human-robot interaction technology is bringing revolutionary progress to productivity. To avoid accidents caused by accidental collisions during robot interaction, protect the safety of operators, robots, and environmental equipment, and adapt to different working conditions, designing a reliable, simple, highly controllable, and rapidly adjustable variable stiffness joint is crucial for improving robot motion performance.

[0003] Variable stiffness mechanisms are a key component of bionic joints and an important part that distinguishes them from traditional rigid actuators. They can directly affect the variable stiffness performance of the joint. Currently, the variable stiffness compliant joints of robots are mainly divided into the following structural principles: (1) Balance position adjustment type, which changes the effective length of the spring plate inside the joint to adjust its flexural stiffness, thereby changing the output stiffness of the joint; (2) Antagonistic action type, which uses a set of springs and antagonistic forces to change the stiffness of the joint, thereby allowing the robot to better adapt to different environments and conditions when performing tasks; (3) Variable structure type, which uses special mechanical structures, such as spring plates, planetary gear trains and crank-slider mechanisms, etc., to adjust the stiffness of the joint by changing the effective working length of the elastic element. Traditional variable stiffness joints are mostly contact transmission, which is prone to fatigue damage. For example, Chinese patent CN106737824A proposes an electromagnetic variable stiffness flexible rotary joint, which achieves the purpose of variable stiffness through radially arranged coils and electromagnetic coupling, and restores the joint to the balance position through spring limiting. However, long-term energization will cause the coil to continuously heat up, accelerate the aging process of the coil, reduce its service life, and cannot work for a long time. For example, Chinese patent CN110978046A proposes a variable stiffness joint based on a cylindrical cam and its control method. By adjusting the attraction between the cylindrical iron-core electromagnet and the annular armature, the roller moves within a curved groove on the cylindrical cam cylinder wall, thereby causing the cylindrical cam cylinder to rotate and generate a restoring torque. The output stiffness of the joint can be changed by altering the current magnitude. However, the continuous contact and relative movement between the cam and the cylinder wall over a long period of time can lead to deformation of the cam profile and a decrease in accuracy. At the same time, the iron-core electromagnet is prone to aging under continuous current operation, affecting the accuracy of the output stiffness. Summary of the Invention

[0004] The purpose of this invention is to provide an active compliant transmission joint and its operating method based on magnetic field control to solve at least one of the aforementioned technical problems, overcoming the issues of complex variable stiffness principles, slow response speed, and high energy consumption for stiffness adjustment in existing technologies. This joint achieves completely contactless transmission, improving the overall reliability of the joint without frictional losses. Furthermore, the output stiffness of this joint is multi-level adjustable, enabling a wide range of stiffness adjustments to meet different stiffness requirements, while also providing beneficial effects in vibration control and shock absorption.

[0005] The present invention achieves the above objectives through the following technical solution: an active compliant transmission joint based on magnetic field control, comprising an output module, a stiffness adjustment module and a position drive module, wherein the output module, stiffness adjustment module and position drive module are connected together in sequence; The output module includes an output disk, a cylindrical nut assembly, a permanent magnet baffle assembly, a sector-shaped permanent magnet assembly I, a bolt I, and a nut I. The sector-shaped permanent magnet assembly I is installed in the built-in groove of the output disk, the permanent magnet baffle assembly is fixedly installed in the circumferential slot of the output disk by the bolt I, and the cylindrical nut is connected to the bolt I in conjunction with the nut I. The stiffness adjustment module includes a connecting plate I, a connecting plate II, and an assembly shaft module. The connecting plate I and the connecting plate II are connected by a double-headed bolt group, and the double-headed bolt group is equipped with a tension spring group. One end of the assembly shaft module is slidably connected to the spline of the center hole of the connecting plate I, and the other end is connected to the inner ring of the bearing III. The outer ring of the bearing III is interference-fitted with the center through hole of the connecting plate II. The assembled shaft module includes a shaft end retaining ring, a double-layer key sleeve, a circular spline shaft, a segmented shaft, a flexible connecting key, a U-shaped spring assembly, a grooved nut, and screw VIII. One end of the circular spline shaft engages with the spline inside the double-layer key sleeve, and a shaft end retaining ring is provided on the shaft body. The other end of the circular spline shaft engages with one end of the segmented shaft using a flexible connecting key. The other end of the segmented shaft is threaded and engages with the grooved nut. The U-shaped spring assembly and screw VIII are installed in the four grooves of the grooved nut. The output module 1 also includes an angular contact ball bearing I, the inner ring of which is interference-fitted onto the cam shaft of the connecting disk I, and the outer ring of which is fixedly mounted to the central cam shaft of the output disk of the output module 1. The stiffness adjustment module also includes a sector-shaped permanent magnet group II, a connecting plate II, a gear group II, a stiffness adjustment motor II, a gear group III, a handwheel and nut group, and a center hole gear. The output shaft of the stiffness adjustment motor II is fixedly installed to the connecting flange. The connecting flange is installed together with the transmission flange by screw IV. The transmission flange is installed on the center hole gear by screw VI. The center hole gear is installed on the segmented shaft of the assembly shaft module near the thread position through bearing II. The grooved nut contacts the inner ring of bearing II to achieve axial fixation of bearing II. At the same time, the circumferentially arranged gear group III is installed on the same shaft as gear group II. On the gear synchronizing shaft, the gear synchronizing shaft is mounted on the connecting plate II via bearing assembly I. The handwheel nut assembly is mounted on the threaded section of the gear synchronizing shaft. Gear assembly III meshes with the central hole gear. The adjusting motor II drives the central hole gear to rotate, thereby driving gear assembly III to rotate. Gear assembly III drives gear assembly II to rotate via the gear synchronizing shaft. Gear assembly II meshes with the spur rack assembly. The connecting plate II is provided with an indexing groove. The sector permanent magnet assembly II is fixedly mounted on the spur rack assembly. The rotation of the central hole gear drives gear assembly II to make the spur rack assembly slide radially on the indexing groove of the connecting plate II. The stiffness adjustment module also includes a cam disc, a stiffness adjustment motor I, a flange I, a pinion I, and a stiffness adjustment gear. The cam disc is fixedly mounted on the connecting disc II. The stiffness adjustment gear is mounted on the central cam of the connecting disc I via an angular contact ball bearing II. The central cam of the connecting disc I has a spline groove that slides with the outer spline of the double-layer key sleeve in the assembly shaft module. At the same time, the connecting disc II has a splined inner hole that engages with the spline on the circular splined shaft of the assembly shaft module. The flange I is fixed to the connecting disc I by screws III. The stiffness adjustment motor I is fixedly mounted to the flange I by screws II. The pinion I is mounted on the output end of the stiffness adjustment motor I and meshes with the stiffness adjustment gear. One end of the stiffness adjustment gear has multiple spiral grooves, and the other end has an arc-shaped cam guide wall I. Each spiral groove corresponds to a cylindrical pin on the end of the sector-shaped magnetic yoke group II. The stiffness adjustment module also includes a sector magnetic yoke module and a connecting plate I. The connecting plate I has an indexing through-slide groove. The sector magnetic yoke module includes sector magnetic yoke group I and sector magnetic yoke group II. Each sector magnetic yoke group I and sector magnetic yoke group II is symmetrically fixed in pairs on the indexing through-slide groove by four screws I. The position drive module includes a drive flange, a hollow harmonic reducer, flange II, and a drive motor. The drive motor is connected to the hollow harmonic reducer via flange II. The output end of the hollow harmonic reducer is connected to the drive flange via screw VII. The other end of the drive flange is fixedly mounted on the annular groove of the connecting plate II using screw VI, so that the position drive module is connected to the stiffness adjustment module. The stiffness adjustment motor II is fixed on the arc-shaped groove of the drive flange via screw V, and the tail of the stiffness adjustment motor II is embedded in the hollow harmonic reducer.

[0006] As a further embodiment of the present invention: both sector-shaped permanent magnet group I and sector-shaped permanent magnet group II are provided with eight sector-shaped permanent magnets, which are symmetrically installed in pairs to form a coupled magnetic field.

[0007] As a further embodiment of the present invention: the connecting disk II is provided with eight uniformly spaced indexing grooves, and the indexing grooves have open slots to allow the gear set II and the ruler rack set to mesh with each other. The eight ruler rack sets are installed in the indexing grooves and slide radially. The fan-shaped permanent magnet set II is fixedly installed on the ruler rack set. The gear set II is provided with eight gears, which are uniformly installed on one end of the eight gear synchronous shafts. The eight gear synchronous shafts are evenly installed in the circumferential holes opened in the connecting disk II through the bearing set I. The other end of the eight gear synchronous shafts is equipped with gear set III.

[0008] As a further embodiment of the present invention: when the sector-shaped permanent magnet group I and the sector-shaped permanent magnet group II are in a directly opposite position, the highest point of the inclined surface of the cam guide wall I and the highest point of the inclined surface of the cam guide wall II are in contact, and the sector-shaped magnetic yoke module is at the proximal end.

[0009] As a further aspect of the present invention, the central angle of the eight spiral grooves opened on the adjusting gear is 90°.

[0010] As a further embodiment of the present invention: the slope of the cam guide wall I provided by the adjusting gear and the cam guide wall II provided by the cam shaft disk are both 45°, and the circumferential angle of the cam guide wall I and the cam guide wall II are both 180°.

[0011] As a further embodiment of the present invention: the cam guide wall I and the cam guide wall II are always in contact under the tension of the tension spring assembly.

[0012] A method for operating an actively compliant drive joint based on magnetic field control, comprising an actively compliant drive joint, the method comprising the following steps: Step 1: Define the adjustment method and range of the first-stage stiffness adjustment. The primary stiffness adjustment mainly measures the relationship between the rotation range of the stiffness adjustment motor II and the radial slip range of the sector permanent magnet group II, and then determines the relationship between the rotation range of the stiffness adjustment motor II and the output stiffness of the active compliant transmission joint, and records the results in the expert knowledge base I; a. Control the stiffness adjustment motor I and stiffness adjustment motor II to position the active compliant drive joint in its initial position; b. The sector-shaped permanent magnet group II is installed on the spur rack group. The radial sliding range of the spur rack group on the straight ruler slide groove is measured on the connecting plate I to obtain the radial sliding range of the sector-shaped permanent magnet group II. The gear group II meshes with the spur rack group. The rotation angle range of the gear group II is determined according to the measured sliding range of the sector-shaped permanent magnet group II. The gear group II and the gear group III are coaxially driven, thus obtaining the relationship between the radial sliding range of the sector-shaped permanent magnet group II and the rotation angle of the gear group III. c. Gear set III meshes with the center hole gear. The rotation angle range of the center hole gear is determined according to the fixed gear transmission ratio. The output end of the adjustable motor II is fixedly installed with the connecting flange to directly drive the center hole gear. The output rotation angle range of the adjustable motor II is determined according to the rotation angle range of the center hole gear. d. Plot the curve showing the relationship between the rotation angle of the adjustable motor II and the radial slip range of the sector permanent magnet group I. Based on the least squares method, perform curve fitting to determine the relationship between the rotation angle of the adjustable motor II and the radial slip of the sector permanent magnet group II. e. Using Maxwell simulation, step-size scanning was performed within the radial sliding range of the sector permanent magnet group II to determine the output torque of the compliant transmission joint at different radial sliding positions of the sector permanent magnet group II. The field quantity calculator was used to process the curve data by angle partial derivative to obtain the relationship between the rotation range of the stiffness adjustment motor II and the output stiffness of the active compliant transmission joint. That is, the adjustment method and adjustment range of the first-stage stiffness adjustment of the active compliant transmission joint were calibrated, and the results were recorded in the expert knowledge base I. Step 2: Define the adjustment method and adjustment range of the secondary stiffness adjustment. The secondary stiffness adjustment mainly measures the relationship between the rotation range of the stiffness adjustment motor I and the output stiffness of the active compliant transmission joint. Specifically, it is reflected in the relationship between the rotation angle of the stiffness adjustment motor I and the radial displacement range of the sector-shaped magnetic yoke module, as well as the axial air gap between the sector-shaped permanent magnet group II and the sector-shaped permanent magnet group I. a. Control the stiffness adjustment motor I and stiffness adjustment motor II to position the active compliant drive joint in its initial position; b. The rotation of the adjusting gear will synchronously affect the radial displacement of the sector-shaped magnetic yoke module and the axial air gap between sector-shaped permanent magnet group II and sector-shaped permanent magnet group I. The adjusting gear is driven to rotate by a fixed step angle to measure the radial displacement of the sector-shaped magnetic yoke module. At the same time, the axial distance between sector-shaped permanent magnet group II and sector-shaped permanent magnet group I is measured. Combining the range of the radial displacement stroke of the sector-shaped magnetic yoke module and the range of the axial distance between sector-shaped permanent magnet group II and sector-shaped permanent magnet group I, the rotation angle range of the adjusting gear is determined. The relationship between the rotation angle of the adjusting gear and the axial air gap length of sector-shaped permanent magnet group II and sector-shaped permanent magnet group I, as well as the relationship between the rotation angle of the adjusting gear and the radial displacement of the sector-shaped magnetic yoke module, are also determined. Finally, the relationship between the change in the axial air gap length of sector-shaped permanent magnet group II and sector-shaped permanent magnet group I and the radial displacement of the sector-shaped magnetic yoke module is determined. c. Pinion I meshes with the adjusting gear. Based on the fixed gear transmission ratio formula, determine the rotation angle range of pinion I. d. Using Maxwell simulation, based on the relationship between the axial air gap length changes of sector permanent magnet group II and sector permanent magnet group I and the radial displacement of sector magnetic yoke module determined in step 3b, synchronous multiple scans are performed on the radial displacement of sector magnetic yoke module and the axial air gap length of sector permanent magnet group II and sector permanent magnet group I. The output torque curves of active compliant transmission joint under different radial positions of sector magnetic yoke module and different axial air gaps of sector permanent magnet group II and sector permanent magnet group I are measured. The curve data are processed by angle partial derivative using a field quantity calculator to obtain the relationship between the rotation range of stiffness adjustment motor I and the output stiffness of active compliant transmission joint, that is, to calibrate the adjustment method and adjustment range of secondary stiffness adjustment, and the results are recorded in expert knowledge base II. Step 3: Based on actual usage requirements, determine the desired value of the output disk rotation stiffness. Based on the expert knowledge base I and expert knowledge base II recorded in Steps 2 and 3, determine whether to enable primary or secondary stiffness adjustment for the active compliant joint. When the desired rotational stiffness is within the first-level stiffness adjustment range, starting from the initial position of the active compliant joint, based on the expert knowledge base I of the relationship between the output stiffness of the output disk and the rotation angle of the stiffness adjustment motor II, the position controller controls the stiffness adjustment motor II to rotate to the desired output angle through the servo driver. The stiffness adjustment motor II drives the center hole gear to output a specified angle. The center hole gear meshes with the gear set III, which drives the gear set II to rotate to the desired angle through the synchronous shaft of the drive gear. At this time, the spur rack set meshing with the gear set II is driven by the gear set II to slide to the specified displacement in the indexing slide. The sector permanent magnet set II is fixed at the tail end of the spur rack set and slides radially synchronously with the spur rack set, thereby changing the centering area of ​​the sector permanent magnet set II and the sector permanent magnet set I. After the stiffness adjustment work is completed, the stiffness adjustment motor II is de-energized and the drive motor is started, and the output disk rotates under the desired rotational stiffness. When the desired rotational stiffness is within the range of the second-level stiffness adjustment, the active compliant joint is reset to its initial position. Based on the expert knowledge base II regarding the relationship between the output stiffness of the output disk and the rotation angle of the stiffness adjustment motor I, the position controller controls the stiffness adjustment motor I to rotate to the desired output angle via the servo driver. The stiffness adjustment motor I drives the pinion I to rotate by a specified angle. The pinion I meshes with the stiffness adjustment gear and drives the stiffness adjustment gear to rotate by a specified angle. The stiffness adjustment gear synchronously drives the sector magnetic yoke module to shift to the specified position in the direction of the distal end. At the same time, the air gap between the coupling axial direction of the sector permanent magnet group II and the sector permanent magnet group I changes. After the stiffness adjustment work is completed, the stiffness adjustment motor I and the power-off brake are deactivated, the drive motor is started, and the output disk rotates under the desired rotational stiffness.

[0013] The beneficial effects of this invention are: This invention utilizes magnetic coupling technology to achieve variable stiffness transmission. Since there is no physical contact during the transmission process, there is no friction loss, which makes the life of the contactless transmission system longer and improves the stability of the entire joint. This joint uses pure permanent magnet coupling transmission, which requires very little maintenance compared to electromagnetic coils. It almost does not require the replacement of parts, reducing the demand for excitation current. Therefore, it has lower energy loss and higher efficiency. The first-level stiffness adjustment of the joint is achieved by cleverly utilizing a gear and rack mechanism. At the same time, the magnetic coupling gap is changed by adopting an integrated structure of cam and gear, and the radial position of the sector magnetic yoke module is changed by using a spiral slide, so as to achieve the synchronous second-level stiffness adjustment. This variable stiffness joint can dynamically and quickly adjust its response characteristics according to external loads. The multi-level stiffness adjustment increases the range of joint stiffness adjustment, thereby maintaining good adaptability in the working environment. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the active compliant transmission joint structure based on magnetic field control according to the present invention. Figure 2 This is an exploded view of the active compliant transmission joint based on magnetic field control according to the present invention. Figure 3 This is an exploded view of the stiffness adjustment module of the present invention; Figure 4 This is an exploded view of the stiffness output module of the present invention; Figure 5 This is a schematic diagram of the installation of connecting disk I and connecting disk II of the present invention; Figure 6 This is a schematic diagram of the first-stage stiffness adjustment transmission process of the present invention; Figure 7 This is a schematic diagram of the two-stage stiffness adjustment transmission process of the present invention; Figure 8 This is a schematic diagram of the output disk structure of the present invention; Figure 9 This is a schematic diagram of the connecting disk II structure of the present invention; Figure 10 This is an exploded view of the assembled shaft module of the present invention; Figure 11 This is a flowchart illustrating the process of the active compliant transmission joint based on magnetic field control of the present invention. Figure 12 This is a simplified diagram of a first-stage stiffness adjustment embodiment of the active compliant transmission joint based on magnetic field control according to the present invention; Figure 13 This is a simplified diagram of a two-stage stiffness adjustment embodiment of the active compliant transmission joint based on magnetic field control according to the present invention; In the diagram: 1. Output module; 2. Stiffness adjustment module; 3. Position drive module; 4. Expert knowledge base I; 5. Position controller; 6. Servo driver; 7. Expert knowledge base II; 1-1. Cylindrical nut assembly; 1-2. Output disk; 1-3. Permanent magnet baffle assembly; 1-4. Sector permanent magnet assembly I; 1-5. Bolt I; 1-6. Nut I; 1-7. Angular contact ball bearing I; 1-8. Built-in groove; 1-9. Circumferential slot; 2-1. Sector magnetic yoke module; 2-1-1. Sector magnetic yoke assembly I; 2-1-2. Sector magnetic... 2-2. Yoke assembly II; 2-3. Screw I; 2-4. Cam guide wall I; 2-5. Connecting disc I; 2-6. Adjustable motor I; 2-7. Flange I; 2-8. Screw III; 2-9. Pinion I; 2-10. Adjustable gear; 2-11. Angular contact ball bearing II; 2-12. Assembly shaft module; 2-13. Cam guide wall II; 2-14. Cam shaft disc; 2-15. Sector permanent magnet assembly II; 2-16. Straight rack assembly; 2-17. Connecting disc II; 2-18. Nut assembly II; 2-19. Double... 2-20. Head bolt assembly; 2-21. Tension spring assembly; 2-22. Nut assembly III; 2-23. Gear assembly II; 2-24. Gear synchronous shaft; 2-25. Gear assembly III; 2-26. Handwheel nut assembly; 2-27. Bearing assembly I; 2-28. Bearing II; 2-29. Center hole gear; 2-30. Transmission flange; 2-30. Screw IV; 2-31. Screw V; 2-32. Connecting flange; 2-33. Adjustable motor II; 2-34. Screw VI; 2-35. Bearing III; 2-36. Spiral groove; 2-37. 2-38. Indexing groove; 2-39. Opening groove; 2-40. Circumferential hole; 3-1. Annular groove; 3-2. Drive flange; 3-3. Hollow harmonic reducer; 3-3. Flange II; 3-4. Drive motor; 3-5. Screw VII; 2-12-1. Shaft end retaining ring; 2-12-2. Double key sleeve; 2-12-3. Circular spline shaft; 2-12-4. Segmented shaft; 2-12-5. Flexible connecting key; 2-12-6. U-shaped spring assembly; 2-12-7. Groove nut; 2-12-8. Screw VIII. Detailed Implementation

[0015] 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.

[0016] Example 1, as Figures 1 to 10As shown, an active compliant transmission joint based on magnetic field control includes an output module 1, a stiffness adjustment module 2, and a position drive module 3, which are connected together in sequence. The output module 1 includes an output disk 1-2, a cylindrical nut assembly 1-1, a permanent magnet baffle assembly 1-3, a sector-shaped permanent magnet assembly I1-4, a bolt I1-5, and a nut I1-6. The sector-shaped permanent magnet assembly I1-4 is installed in the built-in groove 1-8 of the output disk 1-2. The permanent magnet baffle assembly 1-3 is fixedly installed in the circumferential slot 1-9 of the output disk 1-2 by the bolt I1-5. The cylindrical nut 1-1 and the nut I1-6 are connected to the bolt I1-5. The engagement of the cylindrical nut 1-1 and the nut I1-6 prevents the bolt I1-5 from loosening, thereby keeping the position of the sector-shaped permanent magnet assembly I1-4 relative to the output disk 1-2 unchanged. The stiffness adjustment module 2 includes a connecting plate I 2-4, a connecting plate II 2-17, and an assembly shaft module 2-12. The connecting plate I 2-4 and the connecting plate II 2-17 are connected by a double-headed bolt group 2-19, and the double-headed bolt group 2-19 is equipped with a tension spring group 2-20. One end of the assembly shaft module 2-12 is slidably connected to the spline of the center hole of the connecting plate I 2-4, and the other end is connected to the inner ring of the bearing III 2-35. The outer ring of the bearing III 2-35 is interference-fitted with the center through hole of the connecting plate II 2-17. The double-headed bolt group 2-19 and the assembly shaft module 2-12 work together to change the axial distance between the connecting plate I 2-4 and the connecting plate II 2-17. The assembled shaft module 2-12 includes a shaft end retaining ring 2-12-1, a double-layer key sleeve 2-12-2, a circular splined shaft 2-12-3, a segmented shaft 2-12-4, a flexible connecting key 2-12-5, a U-shaped spring assembly 2-12-6, a grooved nut 2-12-7, and a screw VIII 2-12-8. One end of the circular splined shaft 2-12-3 engages with the inner spline of the double-layer key sleeve 2-12-2, and the shaft body of the circular splined shaft 2-12-3 is provided with a shaft end retaining ring 2-12-1. The shaft end retaining ring 2-12-1 prevents the double-layer key sleeve 2-12-2 from engaging with the inner spline of the double-layer key sleeve 2-12-2. The axial offset of 12-2, the other end of the circular spline shaft 2-12-3 and one end of the segmented shaft 2-12-4 are connected by an elastic connecting key 2-12-5. The elastic connecting key 2-12-5 facilitates the disassembly and replacement of the circular spline shaft 2-12-3 and the segmented shaft 2-12-4. The other end of the segmented shaft 2-12-4 is threaded and engages with the grooved nut 2-12-7. The U-shaped spring group 2-12-6 is installed in the four grooves of the grooved nut 2-12-7 with screw VIII 2-12-8 to prevent the grooved nut 2-12-7 from failing to tighten. Output module 1 also includes angular contact ball bearing I1-7. The inner ring of angular contact ball bearing I1-7 is interference-fitted onto the convex shaft of connecting disk I2-4, and the outer ring of angular contact ball bearing I1-7 is fixedly installed with the central convex shaft of output disk 1-2 of output module 1. Angular contact ball bearing I1-7 ensures that connecting disk I2-4 and output disk 1-2 can only rotate relative to each other and cannot move axially. The overall series arrangement scheme realizes the decoupling of motion between joint position output and stiffness adjustment. The stiffness adjustment module 2 also includes a sector-shaped permanent magnet group II2-15, a connecting plate II2-17, a gear group II2-22, a stiffness adjustment motor II2-33, a gear group III2-24, a handwheel nut group 2-25, and a center hole gear 2-28. The output shaft of the stiffness adjustment motor II2-33 is fixedly installed with the connecting flange 2-32. The connecting flange 2-32 is installed together with the transmission flange 2-29 by screw IV2-30. The transmission flange 2-29 is installed with screw VI2-34. On the center hole gear 2-28, the center hole gear 2-28 is mounted on the segmented shaft 2-12-4 of the assembly shaft module 2-12 near the thread position via bearing II 2-27. The grooved nut 2-12-7 contacts the inner ring of bearing II 2-27 to axially fix bearing II 2-27. At the same time, the circumferentially arranged gear set III 2-24 and gear set II 2-22 are mounted on the gear synchronous shaft 2-23, and the gear synchronous shaft 2-23 is mounted via bearing set I 2-26. Mounted on connecting disc II2-17, handwheel nut assembly 2-25 is installed on the threaded section of gear synchronizer shaft 2-23 to prevent axial movement of gear assembly III2-24. Gear assembly III2-24 meshes with center hole gear 2-28. Adjusting motor II2-33 drives center hole gear 2-28 to rotate, thereby driving gear assembly III2-24 to rotate. Gear assembly III2-24 drives gear assembly II2-22 to rotate via gear synchronizer shaft 2-23. Gear assembly II2-22 meshes with spur gear... The rack assembly 2-16 meshes, and the connecting disc II 2-17 is provided with an indexing groove 2-37. The sector-shaped permanent magnet assembly II 2-15 is fixedly installed on the spur rack assembly 2-16. The rotation of the central hole gear 2-28 drives the gear assembly II 2-22 to make the spur rack assembly 2-16 slide radially on the indexing groove 2-37 of the connecting disc II 2-17, thereby changing the effective magnetic flux area of ​​the sector-shaped permanent magnet assembly II 2-15 and the sector-shaped permanent magnet assembly I 1-4, and thus changing the magnetic field force to achieve first-level stiffness adjustment. The stiffness adjustment module 2 also includes a cam disc 2-14, a stiffness adjustment motor I 2-5, a flange I 2-6, a pinion I 2-9, and a stiffness adjustment gear 2-10. The cam disc 2-14 is fixedly mounted on the connecting disc II 2-17. The cam disc 2-14 has a cam guide wall II 2-13 at its center. The stiffness adjustment gear 2-10 is mounted on the central cam of the connecting disc I 2-4 via an angular contact ball bearing II 2-11. The central cam of the connecting disc I 2-4 has a spline groove that slides with the outer spline of the double-layer key sleeve 2-12-2 in the assembly shaft module 2-12. At the same time, the connecting disc II 2-17 has a splined inner hole that engages with the spline on the circular splined shaft 2-12-3 of the assembly shaft module 2-12. The flange I 2-6 is fixed by screws III 2-8. On the connecting plate I2-4, the adjusting motor I2-5 is fixedly mounted on the flange I2-6 by screws II2-7. The pinion I2-9 is installed at the output end of the adjusting motor I2-5 and meshes with the adjusting gear 2-10. One end of the adjusting gear 2-10 is provided with multiple spiral grooves 2-36, and the other end is provided with an arc-shaped cam guide wall I2-3. Each spiral groove 2-36 corresponds to a cylindrical pin at the end of the sector magnetic yoke group II2-1-2. The rotation of the adjusting gear 2-10 drives the sector magnetic yoke group II2-1-2 to move radially under the action of the spiral grooves 2-36, thereby changing the average permeability of the medium between the sector permanent magnet group I1-4 and the sector permanent magnet group II2-15, thus changing the magnetic flux density of the coupled magnetic field. Simultaneously, when the adjusting gear 2-10 rotates, the arc-shaped cam guide wall I2-3 of the adjusting gear 2-10 interacts with the arc-shaped cam guide wall II2-13 of the cam shaft disk 2-14, causing the connecting disks I2-4 and II2-17 to shift axially, while the axial distance between the connecting disk I2-4 and the output disk 1-2 remains unchanged. Therefore, the total air gap of the coupled magnetic field changes, thereby changing the magnetic field strength. Here, the adjustment of the magnetic flux density and magnetic coupling air gap by the adjusting motor I2-5 of the coupled magnetic field will be carried out synchronously to achieve two-stage adjusting. The stiffness adjustment module 2 also includes a sector magnetic yoke module 2-1 and a connecting plate I2-4. The connecting plate I2-4 has an indexing through-slide groove. The sector magnetic yoke module 2-1 includes a sector magnetic yoke group I2-1-1 and a sector magnetic yoke group II2-1-2. Each sector magnetic yoke group I2-1-1 and sector magnetic yoke group II2-1-2 is symmetrically fixed in pairs by four screws I2-2 to form a sector magnetic yoke module 2-1 that moves radially synchronously. It is installed on the indexing through-slide groove of the connecting plate I2-4 by a cylindrical pin at the root of the sector magnetic yoke group II2-1-2. The sector magnetic yoke module 2-1 can slide radially on the indexing through-slide groove of the connecting plate I2-4. The position drive module 3 includes a drive flange 3-1, a hollow harmonic reducer 3-2, a flange II 3-3, and a drive motor 3-4. The drive motor 3-4 is connected to the hollow harmonic reducer 3-2 through the flange II 3-3. The output end of the hollow harmonic reducer 3-2 is connected to the drive flange 3-1 through screw VII 3-5. The other end of the drive flange 3-1 is fixedly installed on the annular groove 2-40 of the connecting plate II 2-17 with screw VI 2-34, so that the position drive module 3 is connected to the stiffness adjustment module 2. The stiffness adjustment motor II 2-33 is fixed on the arc-shaped groove of the drive flange 3-1 through screw V 2-31. The adjustable motor II2-33 is mounted on the drive flange 3-1 by screws 2-31, and the tail of the adjustable motor II2-33 is embedded in the hollow harmonic reducer 3-2.

[0017] Example 2: In addition to all the technical features in Example 1, this example also includes: each of the sector-shaped permanent magnet group I1-4 and sector-shaped permanent magnet group II2-15 is provided with eight sector-shaped permanent magnets, which are symmetrically installed in pairs to form a coupled magnetic field.

[0018] The connecting plate II2-17 is provided with eight evenly spaced indexing grooves 2-37. The indexing grooves 2-37 have opening slots 2-38 to allow gear set II2-22 to mesh with ruler rack set 2-16. The eight ruler rack sets 2-16 are installed in the indexing grooves 2-37 and slide radially. The sector permanent magnet set II2-15 is fixedly installed on the ruler rack set 2-16. Gear set II2-22 is provided with eight gears, which are evenly installed on one end of eight gear synchronous shafts 2-23. The eight gear synchronous shafts 2-23 are evenly installed in the circumferential holes 2-39 opened in the connecting plate II2-17 through bearing set I2-26. Gear set III2-24 is installed on the other end of the eight gear synchronous shafts 2-23.

[0019] When the sector-shaped permanent magnet group I1-4 and sector-shaped permanent magnet group II2-15 are in the opposite position, the highest point of the inclined surface of the cam guide wall I2-3 is in contact with the highest point of the inclined surface of the cam guide wall II2-13, and the sector-shaped magnetic yoke module 2-1 is in the position where the magnetic flux area of ​​the proximal end magnetic yoke is the smallest and the magnetic flux intensity is the smallest. At this time, the active compliant transmission joint is in the initial position.

[0020] The central angle of the eight spiral grooves 2-36 on the adjusting gear 2-10 is 90°.

[0021] The cam guide wall I2-3 of the stiffening gear 2-10 and the cam guide wall II2-13 of the cam shaft disk 2-14 both have an inclination of 45°, and the circumferential angle of the cam guide wall I2-3 and the cam guide wall II2-13 is 180°. When viewed from the spiral groove 2-36 side, when the stiffening gear 2-10 rotates 90° counterclockwise from the initial position, the axial distance between the connecting disk I2-4 and the connecting disk II2-17 is the smallest, and the sector magnetic yoke module 2-1 is located at the distal end. At this time, the magnetic permeability of the magnetic medium of the coupled magnetic field is the largest and the magnetic coupling gap is the smallest. The output stiffness of the active compliant transmission joint under the second stiffness is the largest.

[0022] Cam guide wall I2-3 and cam guide wall II2-13 are always in contact under the tension of tension spring assembly 2-20.

[0023] Example 3, as Figure 11 As shown, a method for operating an active compliant drive joint based on magnetic field control includes an active compliant drive joint, and the method includes the following steps: Step 1: Define the adjustment method and range of the first-stage stiffness adjustment. The primary stiffness adjustment mainly measures the relationship between the rotation range of the stiffness adjustment motor II2-33 and the radial slip range of the sector permanent magnet group II2-15. Then, it determines the relationship between the rotation range of the stiffness adjustment motor II2-33 and the output stiffness of the active compliant transmission joint, and records the results in the expert knowledge base I4.

[0024] a. Control the stiffening motor I2-5 and stiffening motor II2-33 to position the active compliant drive joint in its initial position; b. The sector-shaped permanent magnet group II2-15 is installed on the straight rack group 2-16. The radial sliding range of the straight rack group 2-16 on the straight ruler groove is measured on the connecting plate I2-4 to obtain the radial sliding range of the sector-shaped permanent magnet group II2-15. The gear group II2-22 meshes with the straight rack group 2-16. The rotation angle range of the gear group II2-22 is determined according to the measured sliding range of the sector-shaped permanent magnet group II2-15. The gear group II2-22 and the gear group III2-24 are coaxially driven, thus obtaining the relationship between the radial sliding range of the sector-shaped permanent magnet group II2-15 and the rotation angle of the gear group III2-24. c. Gear set Ⅲ2-24 meshes with center hole gear 2-28. The rotation angle range of center hole gear 2-28 is determined according to the fixed gear transmission ratio. The output end of the adjustable motor Ⅱ2-33 is fixedly installed with the connecting flange 2-32 to directly drive center hole gear 2-28. The output rotation angle range of the adjustable motor Ⅱ2-33 is determined according to the rotation angle range of center hole gear 2-28. d. Plot the curve relating the rotation angle of the adjustable motor II2-33 to the radial slip range of the sector permanent magnet group I1-4. Based on the least squares method, perform curve fitting to determine the relationship between the rotation angle of the adjustable motor II2-33 and the radial slip of the sector permanent magnet group II2-15. e. Using Maxwell simulation, step-size scanning was performed within the radial sliding range of the sector permanent magnet group II2-15 to determine the output torque of the compliant transmission joint at different radial sliding positions of the sector permanent magnet group II2-15. The curve data was processed by the field quantity calculator to obtain the relationship between the rotation range of the stiffness adjustment motor II2-33 and the output stiffness of the active compliant transmission joint. That is, the adjustment method and adjustment range of the first-stage stiffness adjustment of the active compliant transmission joint were calibrated, and the results were recorded in the expert knowledge base I4. Step 2: Define the adjustment method and adjustment range of the secondary stiffness adjustment. The secondary stiffness adjustment mainly measures the relationship between the rotation range of the stiffness adjustment motor I2-5 and the output stiffness of the active compliant transmission joint. Specifically, it is reflected in the relationship between the rotation angle of the stiffness adjustment motor I2-5 and the radial displacement range of the sector magnetic yoke module 2-1, as well as the axial air gap between the sector permanent magnet group II2-15 and the sector permanent magnet group I1-4. a. Control the stiffening motor I2-5 and stiffening motor II2-33 to position the active compliant drive joint in its initial position; b. The rotation of the stiffening gear 2-10 will synchronously affect the radial displacement of the sector magnetic yoke module 2-1 and the axial air gap between sector permanent magnet group II 2-15 and sector permanent magnet group I 1-4. The stiffening gear 2-10 is driven to rotate by a fixed step angle to measure the radial displacement of the sector magnetic yoke module 2-1. At the same time, the axial distance between sector permanent magnet group II 2-15 and sector permanent magnet group I 1-4 is measured. Combining the range of the radial displacement stroke of the sector magnetic yoke module 2-11 and the range of the axial distance between sector permanent magnet group II 2-15 and sector permanent magnet group I 1-4, the rotation angle range of the stiffening gear 2-10 is determined. The relationship between the rotation angle of the adjusting gear 2-10 and the axial air gap lengths of the sector permanent magnet group II 2-15 and sector permanent magnet group I 1-4 was determined, as well as the relationship between the rotation angle of the adjusting gear 2-10 and the radial displacement of the sector magnetic yoke module 2-1. The relationship between the changes in the axial air gap lengths of the sector permanent magnet group II 2-15 and sector permanent magnet group I 1-4 and the radial displacement of the sector magnetic yoke module 2-1 was also determined. c. The pinion I2-9 meshes with the adjusting gear 2-10. The rotation angle range of the pinion I2-9 is determined according to the fixed gear transmission ratio formula. d. Using Maxwell simulation, based on the relationship between the axial air gap length changes of sector permanent magnet group II2-15 and sector permanent magnet group I1-4 and the radial displacement of sector magnetic yoke module 2-1 determined in step 3b, synchronous multiple scans were performed on the radial displacement of sector magnetic yoke module 2-1 and the axial air gap lengths of sector permanent magnet group II2-15 and sector permanent magnet group I1-4. The output torque curves of the active compliant transmission joint under different radial positions of sector magnetic yoke module 2-1 and different axial air gaps of sector permanent magnet group II2-15 and sector permanent magnet group I1-4 were measured. The field quantity calculator was used to process the curve data by angle partial derivative to obtain the relationship between the rotation range of stiffness adjustment motor I2-5 and the output stiffness of active compliant transmission joint, that is, to calibrate the adjustment method and adjustment range of secondary stiffness adjustment, and the results were recorded in expert knowledge base II7. Step 3: Based on actual usage requirements, determine the expected value of the rotational stiffness of output disk 1-2. Based on the expert knowledge base I4 and expert knowledge base II7 recorded in Step 2 and Step 3, determine whether the active compliant joint should use primary or secondary stiffness adjustment. like Figure 12 As shown, when the desired rotational stiffness is within the first-level stiffness adjustment range, starting from the initial position of the active compliant joint, based on the expert knowledge base I4 of the relationship between the output stiffness of the output disk 1-2 and the rotation angle of the stiffness adjustment motor II2-33, the position controller 5 controls the stiffness adjustment motor II2-33 to rotate to the desired output angle via the servo driver 6. The stiffness adjustment motor II2-33 drives the center hole gear 2-28 to output the specified angle. The center hole gear 2-28 meshes with the gear set III2-24, which drives the 8-gear synchronous shaft 2-23 to rotate the gear set II2-22. When the desired angle is reached, the spur rack group 2-16, which meshes with the gear group Ⅱ2-22, is driven by the gear group Ⅱ2-22 to slide to the specified displacement in the indexing groove. The sector permanent magnet group Ⅱ2-15 is fixed at the tail end of the spur rack group 2-16 and slides radially synchronously with the spur rack group 2-16, thereby changing the centering area of ​​the sector permanent magnet group Ⅱ2-15 and the sector permanent magnet group Ⅰ1-4. After the stiffness adjustment work is completed, the stiffness adjustment motor Ⅱ2-33 is de-energized and the brake is engaged, and the drive motor 3-4 is started. The output disk 1-2 rotates under the desired rotational stiffness. like Figure 13As shown, when the desired rotational stiffness is within the range of the second-level stiffness adjustment, the active compliant joint is reset to the initial position. According to the expert knowledge base II7 of the relationship between the output stiffness of the output disk 1-2 and the rotation angle of the stiffness adjustment motor I2-5, the position controller 5 controls the stiffness adjustment motor I2-5 to rotate to the desired output angle through the servo driver 6. The stiffness adjustment motor I2-5 drives the pinion I2-9 to rotate by a specified angle. The pinion I2-9 meshes with the stiffness adjustment gear 2-10 and drives the stiffness adjustment gear 2-10 to rotate by a specified angle. The stiffness adjustment gear 2-10 synchronously drives the sector magnetic yoke module 2-1 to shift to the specified position in the direction of the distal end. At the same time, the air gap of the coupling axial direction of the sector permanent magnet group II2-15 and the sector permanent magnet group I1-4 changes. After the stiffness adjustment work is completed, the stiffness adjustment motor I2-5 and the power-off brake are activated, and the drive motor 3-4 is started. The output disk 1-2 rotates under the desired rotational stiffness.

[0025] The sector-shaped permanent magnet assembly I1-4 is fixed on the output disk 1-2 of the output module 1, forming a coupled transmission with the sector-shaped permanent magnet assembly II2-15 fixed on the connecting disk II2-17. The stiffness-adjusting motor I2-5 is fixed on the connecting disk I2-4 to achieve radial offset of the yoke and change of the permanent magnet air gap. The stiffness-adjusting motor II2-33 is fixed on the connecting disk II2-17 to achieve radial movement of the sector-shaped permanent magnet assembly II2-15, thereby changing the effective area of ​​the magnetic flux. By controlling the stiffness-adjusting motor, the effective area and magnetic flux density of the sector-shaped permanent magnet assemblies I1-4 and II2-15 can be effectively changed, thereby changing the magnetic field force to change the output stiffness. Using expert knowledge bases I4 and II7, the stiffness-adjusting motors I2-5 and II2-33 output a specified rotation angle. Under the drive of the drive motor 3-4, the magnetic field control has almost no response lag and low energy consumption.

[0026] It will be apparent to those skilled in the art that the present 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 its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0027] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A magnetic field-controlled active compliant transmission joint, comprising an output module (1), a stiffness adjustment module (2), and a position drive module (3), characterized in that: The output module (1), stiffness adjustment module (2) and position drive module (3) are connected together in sequence; The output module (1) includes an output disk (1-2), a cylindrical nut assembly (1-1), a permanent magnet baffle assembly (1-3), a sector-shaped permanent magnet assembly I (1-4), a bolt I (1-5), and a nut I (1-6); the sector-shaped permanent magnet assembly I (1-4) is installed in the built-in groove (1-8) of the output disk (1-2), the permanent magnet baffle assembly (1-3) is fixedly installed in the circumferential slot (1-9) of the output disk (1-2) by bolt I (1-5), and the cylindrical nut (1-1) is connected to the nut I (1-6) by fitting on the bolt I (1-5); The stiffness adjustment module (2) includes a connecting plate I (2-4), a connecting plate II (2-17), and an assembly shaft module (2-12). The connecting plate I (2-4) and the connecting plate II (2-17) are connected by a double-headed bolt group (2-19), and the double-headed bolt group (2-19) is provided with a tension spring group (2-20). One end of the assembly shaft module (2-12) is slidably connected to the spline of the center hole of the connecting plate I (2-4), and the other end is connected to the inner ring of the bearing III (2-35). The outer ring of the bearing III (2-35) is interference-fitted with the center through hole of the connecting plate II (2-17). The assembled shaft module (2-12) includes a shaft end retaining ring (2-12-1), a double-layer key sleeve (2-12-2), a circular splined shaft (2-12-3), a segmented shaft (2-12-4), a flexible connecting key (2-12-5), a U-shaped spring assembly (2-12-6), a grooved nut (2-12-7), and screw VIII (2-12-8). One end of the circular splined shaft (2-12-3) mates with the internal spline of the double-layer key sleeve (2-12-2), and the circular spline... The shaft (2-12-3) is provided with a shaft end retaining ring (2-12-1). The other end of the circular spline shaft (2-12-3) is engaged with one end of the segmented shaft (2-12-4) by an elastic connecting key (2-12-5). The other end of the segmented shaft (2-12-4) is threaded and engages with a grooved nut (2-12-7). The U-shaped spring assembly (2-12-6) is engaged with screw VIII (2-12-8) and installed in the four grooves of the grooved nut (2-12-7). The output module (1) also includes an angular contact ball bearing I (1-7), the inner ring of which is interference-fitted onto the cam shaft of the connecting disk I (2-4), and the outer ring of which is fixedly mounted to the central cam shaft of the output disk (1-2) of the output module (1). The stiffness adjustment module (2) further includes a sector-shaped permanent magnet group II (2-15), a connecting plate II (2-17), a gear group II (2-22), a stiffness adjustment motor II (2-33), a gear group III (2-24), a handwheel nut group (2-25), and a center hole gear (2-28). The output shaft of the stiffness adjustment motor II (2-33) is fixedly installed with the connecting flange (2-32). The connecting flange (2-32) is installed together with the transmission flange (2-29) by screw IV (2-30). The flange (2-29) is mounted on the center hole gear (2-28) by screw VI (2-34). The center hole gear (2-28) is mounted on the segmented shaft (2-12-4) of the assembly shaft module (2-12) near the thread position via bearing II (2-27). The grooved nut (2-12-7) contacts the inner ring of bearing II (2-27) to axially fix bearing II (2-27). At the same time, the circumferentially arranged gear set III (2-24) and gear set II (2-22) are mounted on the gear... On the gear synchronizing shaft (2-23), the gear synchronizing shaft (2-23) is mounted on the connecting disc II (2-17) via bearing assembly I (2-26). The handwheel nut assembly (2-25) is mounted on the threaded section of the gear synchronizing shaft (2-23). ​​The gear set III (2-24) meshes with the center hole gear (2-28). The adjusting motor II (2-33) drives the center hole gear (2-28) to rotate, thereby driving the gear set III (2-24) to rotate. The gear set III (2-24) is connected to the gear synchronizing shaft (2-23) via the gear synchronizing shaft (2-24). Shaft (2-23) drives gear set II (2-22) to rotate; gear set II (2-22) meshes with spur rack set (2-16); the connecting disk II (2-17) is provided with indexing groove (2-37); the sector permanent magnet set II (2-15) is fixedly installed on spur rack set (2-16); the rotation of the central hole gear (2-28) drives gear set II (2-22) to make spur rack set (2-16) slide radially on the indexing groove (2-37) of connecting disk II (2-17); The stiffness adjustment module (2) further includes a cam disc (2-14), a stiffness adjustment motor I (2-5), a flange I (2-6), a pinion I (2-9), and a stiffness adjustment gear (2-10). The cam disc (2-14) is fixedly mounted on the connecting disc II (2-17). The stiffness adjustment gear (2-10) is mounted on the central cam of the connecting disc I (2-4) via an angular contact ball bearing II (2-11). The central cam of the connecting disc I (2-4) has a spline groove that slides with the outer spline of the double-layer key sleeve (2-12-2) in the assembly shaft module (2-12). Meanwhile, the connecting disc II (2-17) has a splined inner hole that connects with the assembly shaft module (2-12). A circular spline shaft (2-12-3) is splinedly connected; the flange I (2-6) is fixed to the connecting plate I (2-4) by screw III (2-8); the adjusting motor I (2-5) is fixedly installed on the flange I (2-6) by screw II (2-7); the pinion I (2-9) is installed at the output end of the adjusting motor I (2-5) and meshes with the adjusting gear (2-10); one end of the adjusting gear (2-10) is provided with multiple spiral grooves (2-36), and the other end is provided with an arc-shaped cam guide wall I (2-3); each spiral groove (2-36) corresponds to a cylindrical pin at the end of the sector-shaped magnetic yoke group II (2-1-2); The stiffness adjustment module (2) further includes a sector magnetic yoke module (2-1) and a connecting disk I (2-4). The connecting disk I (2-4) has an indexing through-slide groove. The sector magnetic yoke module (2-1) includes sector magnetic yoke group I (2-1-1) and sector magnetic yoke group II (2-1-2). Each sector magnetic yoke group I (2-1-1) and sector magnetic yoke group II (2-1-2) is symmetrically fixed in pairs on the indexing through-slide groove by four screws I (2-2). The position drive module (3) includes a drive flange (3-1), a hollow harmonic reducer (3-2), flange II (3-3), and a drive motor (3-4). The drive motor (3-4) is connected to the hollow harmonic reducer (3-2) through flange II (3-3). The output end of the hollow harmonic reducer (3-2) is connected to the drive flange (3-1) through screw VII (3-5). The other end of the drive flange (3-1) is fixedly installed on the annular groove (2-40) of the connecting plate II (2-17) with screw VI (2-34), so that the position drive module (3) is connected to the stiffness adjustment module (2). The stiffness adjustment motor II (2-33) is fixed on the arc-shaped groove of the drive flange (3-1) through screw V (2-31). The tail of the stiffness adjustment motor II (2-33) is embedded in the hollow harmonic reducer (3-2).

2. The active compliant transmission joint based on magnetic field control according to claim 1, characterized in that: Both the sector-shaped permanent magnet group I (1-4) and the sector-shaped permanent magnet group II (2-15) are equipped with eight sector-shaped permanent magnets, which are symmetrically installed in pairs to form a coupled magnetic field.

3. The active compliant transmission joint based on magnetic field control according to claim 1, characterized in that: The connecting disc II (2-17) is provided with eight evenly spaced indexing grooves (2-37). The indexing grooves (2-37) have opening slots (2-38) to allow gear set II (2-22) to mesh with the ruler rack set (2-16). The eight ruler rack sets (2-16) are installed in the indexing grooves (2-37) and slide radially. The fan-shaped permanent magnet set II (2-15) is fixedly installed on the ruler rack set (2-16). The gear set II (2-22) is provided with eight gears, which are evenly installed on one end of the eight gear synchronous shafts (2-23). ​​The eight gear synchronous shafts (2-23) are evenly installed in the circumferential holes (2-39) opened in the connecting disc II (2-17) through bearing set I (2-26). The other end of the eight gear synchronous shafts (2-23) is equipped with gear set III (2-24).

4. The active compliant transmission joint based on magnetic field control according to claim 1, characterized in that: When the sector-shaped permanent magnet group I (1-4) and sector-shaped permanent magnet group II (2-15) are in a facing position, the highest point of the inclined surface of the cam guide wall I (2-3) and the highest point of the inclined surface of the cam guide wall II (2-13) are in contact, and the sector-shaped magnetic yoke module (2-1) is at the proximal end, it is defined as the initial position of the compliant transmission joint.

5. The active compliant transmission joint based on magnetic field control according to claim 1, characterized in that: The central angle of the eight spiral grooves (2-36) opened on the adjusting gear (2-10) is 90°.

6. The active compliant transmission joint based on magnetic field control according to claim 1, characterized in that: The cam guide wall I (2-3) of the adjusting gear (2-10) and the cam guide wall II (2-13) of the cam shaft disk (2-14) both have an inclination of 45°, and the circumferential angle of the cam guide wall I (2-3) and the cam guide wall II (2-13) is 180°.

7. The active compliant transmission joint based on magnetic field control according to claim 1, characterized in that: The cam guide wall I (2-3) and cam guide wall II (2-13) are always in contact under the tension of the tension spring assembly (2-20).

8. A method for operating an active compliant drive joint based on magnetic field control as described in any one of claims 1 to 7, comprising an active compliant drive joint, characterized in that: The working method includes the following steps: Step 1: Define the adjustment method and range of the first-stage stiffness adjustment. The first-level stiffness adjustment mainly measures the relationship between the rotation range of the stiffness adjustment motor II (2-33) and the radial slip range of the sector permanent magnet group II (2-15), and then determines the relationship between the rotation range of the stiffness adjustment motor II (2-33) and the output stiffness of the active compliant transmission joint, and records the results in the expert knowledge base I (4); a. Control the stiffness adjustment motor I (2-5) and stiffness adjustment motor II (2-33) to position the active compliant drive joint in its initial position; b. The sector-shaped permanent magnet group II (2-15) is installed on the spur rack group (2-16). The radial sliding range of the spur rack group (2-16) on the straight ruler groove is measured on the connecting plate I (2-4) to obtain the radial sliding range of the sector-shaped permanent magnet group II (2-15). The gear group II (2-22) meshes with the spur rack group (2-16). The rotation angle range of the gear group II (2-22) is determined according to the measured sliding range of the sector-shaped permanent magnet group II (2-15). The gear group II (2-22) and the gear group III (2-24) are coaxially driven, thus obtaining the relationship between the radial sliding range of the sector-shaped permanent magnet group II (2-15) and the rotation angle of the gear group III (2-24). c. Gear set III (2-24) meshes with the center hole gear (2-28). The rotation angle range of the center hole gear (2-28) is determined according to the fixed gear transmission ratio. The output end of the adjustable motor II (2-33) is fixedly installed with the connecting flange (2-32) to directly drive the center hole gear (2-28). The output rotation angle range of the adjustable motor II (2-33) is determined according to the rotation angle range of the center hole gear (2-28). d. Plot the curve relating the rotation angle of the adjustable motor II (2-33) to the radial slip range of the sector permanent magnet group I (1-4), and perform curve fitting based on the least squares method to determine the relationship between the rotation angle of the adjustable motor II (2-33) and the radial slip of the sector permanent magnet group II (2-15). e. Using Maxwell simulation, step-size scanning was performed within the radial sliding range of the sector permanent magnet group II (2-15) to measure the output torque of the compliant transmission joint at different radial sliding positions of the sector permanent magnet group II (2-15). The curve data was processed by the field quantity calculator to obtain the relationship between the rotation range of the stiffness adjustment motor II (2-33) and the output stiffness of the active compliant transmission joint. That is, the adjustment method and adjustment range of the first-stage stiffness adjustment of the active compliant transmission joint were calibrated, and the results were recorded in the expert knowledge base I (4). Step 2: Define the adjustment method and adjustment range of the secondary stiffness adjustment. The secondary stiffness adjustment mainly measures the relationship between the rotation range of the stiffness adjustment motor I (2-5) and the output stiffness of the active compliant transmission joint. Specifically, it is reflected in the relationship between the rotation angle of the stiffness adjustment motor I (2-5) and the radial displacement range of the sector magnetic yoke module (2-1) and the axial air gap between the sector permanent magnet group II (2-15) and the sector permanent magnet group I (1-4). a. Control the stiffness adjustment motor I (2-5) and stiffness adjustment motor II (2-33) to position the active compliant drive joint in its initial position; b. The rotation of the stiffening gear (2-10) will synchronously affect the radial displacement of the sector-shaped magnetic yoke module (2-1) and the axial air gap between sector-shaped permanent magnet group II (2-15) and sector-shaped permanent magnet group I (1-4). This drives the stiffening gear (2-10) to rotate by a fixed step angle, measuring the radial displacement of the sector-shaped magnetic yoke module (2-1). Simultaneously, the axial distance between sector-shaped permanent magnet group II (2-15) and sector-shaped permanent magnet group I (1-4) is measured. This, combined with the radial displacement range of the sector-shaped magnetic yoke module (2-1) and the axial distance between sector-shaped permanent magnet group II (2-15) and sector-shaped permanent magnet group I (1-4), is considered. The axial distance range of permanent magnet group I (1-4) is determined, the rotation angle range of the stiffening gear (2-10) is determined, and the relationship between the rotation angle of the stiffening gear (2-10) and the axial air gap length of the sector permanent magnet group II (2-15) and sector permanent magnet group I (1-4) is determined, as well as the relationship between the rotation angle of the stiffening gear (2-10) and the radial displacement of the sector magnetic yoke module (2-1) is determined. The relationship between the change in the axial air gap length of sector permanent magnet group II (2-15) and sector permanent magnet group I (1-4) and the radial displacement of the sector magnetic yoke module (2-1) is determined. c. Pinion I (2-9) meshes with the adjusting gear (2-10). Based on the fixed gear transmission ratio formula, determine the rotation angle range of pinion I (2-9); d. Using Maxwell simulation, according to the relationship between the axial air gap length change of the sector permanent magnet group II (2-15) and sector permanent magnet group I (1-4) and the radial displacement of the sector magnetic yoke module (2-1) determined in step 3 (b), the radial displacement of the sector magnetic yoke module (2-1) and the axial air gap length of the sector permanent magnet group II (2-15) and sector permanent magnet group I (1-4) are simultaneously scanned multiple times. The output torque curves of the active compliant transmission joint under different radial positions of the sector magnetic yoke module (2-1) and different axial air gaps of the sector permanent magnet group II (2-15) and sector permanent magnet group I (1-4) are determined. The curve data are processed by the field quantity calculator to obtain the relationship between the rotation range of the stiffness adjustment motor I (2-5) and the output stiffness of the active compliant transmission joint, that is, to calibrate the adjustment method and adjustment range of the secondary stiffness adjustment, and record the results in the expert knowledge base II (7). Step 3: Based on actual usage requirements, determine the expected value of the rotational stiffness of the output disk (1-2). Based on the expert knowledge base I (4) and expert knowledge base II (7) recorded in Step 2 and Step 3, determine whether the active compliant joint should be adjusted to first-level or second-level stiffness. When the desired rotational stiffness is within the first-level stiffness adjustment range, from the initial position of the active compliant joint, according to the expert knowledge base I (4) of the relationship between the output stiffness of the output disk (1-2) and the rotation angle of the stiffness adjustment motor II (2-33), the position controller (5) controls the stiffness adjustment motor II (2-33) to rotate to the desired output angle through the servo driver (6). The stiffness adjustment motor II (2-33) drives the center hole gear (2-28) to output the specified angle. The center hole gear (2-28) meshes with the gear set III (2-24), which drives the 8-gear synchronous shaft (2-23) to make the gear set II (2-22) rotate. At the desired angle, the spur rack group (2-16) meshing with gear group II (2-22) is driven by gear group II (2-22) to slide to the specified displacement in the indexing groove. The sector permanent magnet group II (2-15) is fixed at the tail end of the spur rack group (2-16) and slides radially synchronously with the spur rack group (2-16), thereby changing the centering area of ​​sector permanent magnet group II (2-15) and sector permanent magnet group I (1-4). After the stiffness adjustment work is completed, the stiffness adjustment motor II (2-33) is de-energized and the drive motor (3-4) is started. The output disk (1-2) rotates under the desired rotational stiffness. When the desired rotational stiffness is within the range of the second-level stiffness adjustment, the active compliant joint is reset to the initial position. According to the expert knowledge base II (7) of the relationship between the output stiffness of the output disk (1-2) and the rotation angle of the stiffness adjustment motor I (2-5), the position controller (5) controls the stiffness adjustment motor I (2-5) to rotate to the desired output angle through the servo driver (6). The stiffness adjustment motor I (2-5) drives the pinion I (2-9) to rotate by a specified angle. The pinion I (2-9) meshes with the stiffness adjustment gear (2-10) to drive the stiffness adjustment gear (2-10) to rotate by a specified angle. The stiffness adjustment gear (2-10) synchronously drives the sector magnetic yoke module (2-1) to shift to the specified position in the direction of the distal end. At the same time, the air gap of the coupling axial direction of the sector permanent magnet group II (2-15) and the sector permanent magnet group I (1-4) changes. After the stiffness adjustment work is completed, the stiffness adjustment motor I (2-5) and the power-off brake are activated, and the drive motor (3-4) is started. The output disk (1-2) rotates under the desired rotational stiffness.

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