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

Abstract

The invention discloses an active flexible transmission joint based on magnetic field regulation and control and a working method. The active flexible transmission joint comprises an output module, a rigidity adjusting module and a position driving module. Variable stiffness transmission is achieved through the magnetic coupling technology, and due to the fact that no physical contact exists in the transmission process, friction loss does not exist, the service life of a non-contact transmission system is longer, and the stability of the whole joint is improved; first-level rigidity adjustment of the joint is achieved through a gear and rack mechanism, meanwhile, a cam and gear integrated structure is adopted to achieve magnetic coupling gap change, a spiral sliding groove is adopted to achieve radial position change of a fan-shaped magnet yoke module, and synchronous second-level rigidity adjustment is achieved. Response characteristics of the joint can be dynamically and rapidly adjusted according to external loads, the joint rigidity adjusting range is enlarged through multi-stage rigidity adjustment, and therefore adaptability is kept in the working environment.

Description

Technical Field

[0001] The invention relates to a transmission joint, in particular to an active compliant transmission joint based on magnetic field regulation and a working method, belonging to the technical field of robot control. Background Art

[0002] The current booming robot industry is greatly changing the production and lifestyle of human beings. With the rise and development of the robot industry, the technology of human-machine interaction has brought revolutionary progress to the development of productivity. In order to avoid accidents caused by accidental collisions during robot interaction, protect the safety of operators, robots and environmental equipment, and adapt to the requirements of different working conditions, a variable stiffness joint with reliable performance, simple structure, high controllability, rapid stiffness adjustment and wide range of changes is designed, which is of great significance to promoting the improvement of robot motion performance.

[0003] The variable stiffness mechanism is a key component of the bionic joint and an important component that is different from the traditional rigid actuator. It can directly affect the variable stiffness performance of the joint. The current robot variable stiffness compliant joints are mainly divided into the following structural principles: (1) Balance position adjustment type, which changes the effective length of the spring sheet built into 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, 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 sheets, planetary gear trains, and crank slider mechanisms, to adjust the stiffness of the joint by changing the effective working length of the elastic element. Traditional variable stiffness joints are mostly contact transmissions and are prone to fatigue damage. For example, the Chinese patent CN106737824A proposes an electromagnetic variable stiffness flexible rotation joint, which achieves the purpose of variable stiffness through radially arranged coils and electromagnetic coupling, and uses spring limiters to restore the joint to a balanced position. However, long-term power-on will cause the coil to continue to heat up, accelerate the aging process of the coil, reduce its service life, and cannot work for a long time. Another example is a variable stiffness joint based on a cylindrical cam and its control method proposed in Chinese patent CN110978046A. By adjusting the suction between the cylindrical iron core electromagnet and the annular armature, the roller moves in the curved groove opened on the cylindrical cam wall, so that the cylindrical cam barrel rotates and generates a restoring torque, and the current is changed to change the output stiffness of the joint. However, the continuous contact and relative movement between the cam and the barrel wall will cause the cam profile to deform and the accuracy to decrease after long-term operation. At the same time, the iron core electromagnet is prone to aging under continuous current working conditions, which affects the accuracy of the output stiffness. Summary of the invention

[0004] The purpose of the present invention is to provide an active compliant transmission joint and working method based on magnetic field control in order to solve at least one of the above technical problems, so as to overcome the problems of complex variable stiffness principle, slow response speed, high energy consumption of stiffness adjustment in the prior art. The joint realizes complete contactless transmission, and improves the reliability of the entire joint without friction loss. At the same time, the output stiffness of the joint adopts multi-level adjustment, which can realize a wide range of stiffness adjustment in response to different stiffness demand scenarios, and has certain beneficial effects in controlling vibration and absorbing impact.

[0005] The present invention achieves the above-mentioned object through the following technical solutions: an active compliant transmission joint based on magnetic field control, comprising an output module, a stiffness adjustment module and a position driving module, wherein the output module, the stiffness adjustment module and the position driving module are connected together in sequence; The output module includes an output disk, a cylindrical nut group, a permanent magnet baffle group, a sector permanent magnet group I, a bolt I and a nut I; the sector permanent magnet group I is installed in a built-in groove opened in the output disk, the permanent magnet baffle group is fixedly installed in a circumferential slot opened in the output disk by bolt I, and the cylindrical nut is matched with the nut I and connected to the bolt I; The stiffness adjustment module includes a connection plate I, a connection plate II, and an assembly shaft module. The connection plate I and the connection plate II are connected by a stud bolt group, and the stud bolt group is provided with a tension spring group. One end of the assembly shaft module is connected to the spline sliding connection of the center hole of the connection plate I, and the other end is connected to the inner ring of the bearing III, and the outer ring of the bearing III is interference fit with the center through hole of the connection plate II. The assembled shaft module includes a shaft end retaining ring, a double-layer key sleeve, a circular spline shaft, a segmented shaft, an elastic connection key, a U-shaped spring group, a slotted nut, and a screw VIII; one end of the circular spline shaft is matched with the inner spline of the double-layer key sleeve, and a shaft end retaining ring is arranged on the shaft body of the circular spline shaft, the other end of the circular spline shaft is matched with one end of the segmented shaft by an elastic connection key, the other end of the segmented shaft is provided with a thread matched with the slotted nut, and the U-shaped spring group is matched with the screw VIII to be installed in the four grooves of the slotted nut; The output module 1 also includes an angular contact ball bearing I, the inner ring of which is interference-mounted on the convex shaft of the coupling disk I, and the outer ring of which is fixedly mounted on the central convex shaft of the output disk of the output module 1; The stiffness adjustment module also includes a sector permanent magnet group II, a connecting plate II, a gear group II, a stiffness adjustment motor II, a gear group III, a handwheel nut group and a center hole gear. The output shaft of the stiffness adjustment motor II is fixedly installed with a connecting flange, the connecting flange is installed with a transmission flange through screws IV, the transmission flange is installed on the center hole gear through screws VI, the center hole gear is installed on the segmented shaft of the assembled shaft module near the threaded position through bearing II, and the grooved nut contacts the inner ring of bearing II to realize the axial fixation of bearing II; at the same time, the circumferentially arranged gear group III and gear group II are installed On the gear synchronization shaft, the gear synchronization shaft is installed on the connecting plate II through the bearing group I, the handwheel nut group is installed on the threaded section of the gear synchronization shaft, the gear group III is meshed with the center hole gear, the rigid adjustment motor II drives the center hole gear to rotate, thereby driving the gear group III to rotate, and the gear group III drives the gear group II to rotate through the gear synchronization shaft; the gear group II is meshed with the spur rack group, and the connecting plate II is provided with an indexing groove, the fan-shaped permanent magnet group II is fixedly installed on the spur rack group, and the center hole gear rotates to drive the gear group II to make the spur rack group radially slide on the indexing groove of the connecting plate II; The stiffness adjustment module also includes a cam disk, a rigidity adjustment motor I, a flange disk I, a pinion I, and a rigidity adjustment gear. The cam disk is fixedly mounted on the connection disk II. The rigidity adjustment gear is mounted on the central cam of the connection disk I through an angular contact ball bearing II. A spline groove is provided in the central cam of the connection disk I for sliding connection with the outer spline of the double-layer key sleeve in the assembly shaft module. At the same time, the connection disk II is provided with a spline inner hole for matching connection with the spline on the circular spline shaft of the assembly shaft module. The flange disk I is fixed on the connection disk I through screws III. The rigidity adjustment motor I is fixedly mounted on the flange disk I through screws II. The pinion I is mounted on the output end of the rigidity adjustment motor I and meshes with the rigidity adjustment gear. A plurality of spiral grooves are provided at one end of the rigidity adjustment gear, and an arc cam guide wall I is provided at the other end. Each spiral groove is matched with a cylindrical pin on the end of the sector yoke group II in a one-to-one correspondence. The stiffness adjustment module also includes a sector yoke module and a coupling plate I. The coupling plate I is provided with a graduated through-type slideway. The sector yoke module includes a sector yoke group I and a sector yoke group II. Each sector yoke group I and sector yoke group II are symmetrically fixed on the graduated through-type slideway in pairs by four screws I. The position drive module includes a driving flange, a hollow harmonic reducer, a flange II, and a driving motor. The driving motor is connected to the hollow harmonic reducer through the flange II, and the output end of the hollow harmonic reducer is connected to the driving flange through the screw VII; the other end of the driving flange is fixedly installed on the annular groove opened on the connecting plate II by the screw VI, so that the position drive module is connected to the stiffness adjustment module, and the stiffness adjustment motor II is fixed on the arc groove of the driving flange by the screw V, and the tail of the stiffness adjustment motor II is embedded in the hollow harmonic reducer.

[0006] As a further solution of the present invention: both the sector-shaped permanent magnet group I and the 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 solution of the present invention: eight uniform indexing grooves are provided on the connecting plate II, and open grooves are opened on the indexing grooves to enable the gear group II and the ruler rack group to mesh with each other. The eight ruler rack groups are installed in the indexing grooves for radial sliding, and the fan-shaped permanent magnet group II is fixedly installed on the ruler rack group; the gear group II is provided with eight gears, which are uniformly installed on one end of the eight gear synchronization shafts, and the eight gear synchronization shafts are uniformly installed in the annular holes opened in the connecting plate II through the bearing group I, and the gear group III is installed on the other end of the eight gear synchronization shafts.

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

[0009] As a further solution of the present invention: the central angle of the eight spiral grooves provided on the rigidity-adjusting gear is 90°.

[0010] As a further solution of the present invention: the inclination of the cam guide wall I provided on the steel-adjusting gear and the cam guide wall II provided on the cam shaft plate are both 45 degrees, and the circumferential angle of the cam guide wall I and the cam guide wall II are both 180 degrees.

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

[0012] A working method of an active compliant transmission joint based on magnetic field regulation, comprising an active compliant transmission joint, the method comprising the following steps: Step 1: Define the adjustment method and adjustment range of the first-level rigidity adjustment The first-level rigidity adjustment mainly determines the relationship between the rotation range of rigidity adjustment motor II and the radial slip range of sector permanent magnet group II, and then determines the relationship between the rotation range of rigidity adjustment motor II and the output stiffness of active compliant transmission joint, and records the results in the expert knowledge base I; a. Control rigidity adjustment motor I and rigidity adjustment motor II to make the active compliant transmission joint located at the initial position; b. The sector permanent magnet group II is installed on the spur rack group. The radial slip range of the sector permanent magnet group II can be obtained by measuring the radial slip range of the spur rack group on the ruler groove on the coupling plate I. The gear group II is meshed with the spur rack group. The rotation angle range of the gear group II is determined according to the measured slip range of the sector permanent magnet group II. The gear group II and the gear group III are coaxially driven, and the relationship between the radial slip range of the sector permanent magnet group II and the rotation angle of the gear group III is obtained. c. Gear set III is meshed with the center hole gear, and the rotation angle range of the center hole gear is determined according to the fixed gear transmission ratio relationship. The output end of the rigid motor II is fixedly installed with the connecting flange to directly drive the center hole gear, and the output rotation angle range of the rigid motor II is determined according to the rotation angle range of the center hole gear; d. Draw the relationship curve between the rotation angle of the rigid motor II and the radial slip range of the sector-shaped permanent magnet group I, and perform curve fitting based on the least squares method to determine the relationship between the rotation angle of the rigid motor II and the radial slip of the sector-shaped permanent magnet group II; e. Using Maxwell simulation, perform step scanning within the radial slip range of the sector permanent magnet group II, measure the output torque of the compliant transmission joint at different radial slip positions of the sector permanent magnet group II, use the field quantity calculator to perform angle derivation processing on the curve data, and 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, calibrate the adjustment method and adjustment range of the first-level stiffness adjustment of the active compliant transmission joint, and record the results in the expert knowledge base I; Step 2: Define the adjustment method and adjustment range of the secondary rigidity adjustment The secondary stiffness adjustment mainly measures the relationship between the rotation range of stiffness adjustment motor I and the output stiffness of the active compliant transmission joint, which is specifically reflected in the relationship between the rotation angle of stiffness adjustment motor I and the radial displacement range of the fan-shaped magnetic yoke module and the axial air gap between fan-shaped permanent magnet group II and fan-shaped permanent magnet group I. a. Control rigidity adjustment motor I and rigidity adjustment motor II to make the active compliant transmission joint located at the initial position; b. The rotation of the rigid gear will synchronously affect the radial displacement of the sector yoke module and the axial air gap between the sector permanent magnet group II and the sector permanent magnet group I, drive the rigid gear to rotate at a fixed step angle, measure the radial displacement of the sector yoke module, and at the same time, measure the axial distance between the sector permanent magnet group II and the sector permanent magnet group I. Combined with the radial displacement range of the sector yoke module and the axial distance range of the sector permanent magnet group II and the sector permanent magnet group I, determine the rotation angle range of the rigid gear, and determine the relationship between the rotation angle of the rigid gear and the axial air gap length of the sector permanent magnet group II and the sector permanent magnet group I, as well as the relationship between the rotation angle of the rigid gear and the radial displacement of the sector yoke module, and determine the relationship between the change in the axial air gap length of the sector permanent magnet group II and the sector permanent magnet group I and the radial displacement of the sector yoke module; c. Pinion I meshes with the rigid gear, and the rotation angle range of pinion I is determined according to the fixed gear transmission ratio formula; d. Using Maxwell simulation, according to the relationship between the change in the axial air gap length of the fan-shaped permanent magnet group II and the fan-shaped permanent magnet group I and the radial displacement of the fan-shaped magnetic yoke module determined in step 3b, perform synchronous multiple scans on the radial displacement of the fan-shaped magnetic yoke module and the axial air gap length of the fan-shaped permanent magnet group II and the fan-shaped permanent magnet group I, measure the output torque curve of the active compliant transmission joint under different radial positions of the fan-shaped magnetic yoke module and different axial air gaps of the fan-shaped permanent magnet group II and the fan-shaped permanent magnet group I, use the field quantity calculator to perform angle partial derivative processing on the curve data, and obtain the relationship between the rotation range of the rigidity-adjusting motor I and the output stiffness of the active compliant transmission joint, that is, calibrate the adjustment method and adjustment range of the secondary rigidity adjustment, and record the results in the expert knowledge base II; Step 3: Determine the expected value of the rotational stiffness of the output disk according to actual use requirements, and determine whether the active compliant joint enables the first-level stiffness adjustment or the second-level stiffness adjustment according to the expert knowledge base I and the expert knowledge base II recorded in steps 2 and 3; 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 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, and the stiffness adjustment motor II drives the center hole gear to output the specified angle, and the center hole gear meshing gear set III drives the gear set II to rotate to the desired angle through the driving gear synchronization shaft. At this time, the spur rack set meshing with the gear set II is driven by the gear set II to slide in the indexing slide to the specified displacement, and 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 powered off and braked, and the drive motor is started, and the output disk rotates at the desired rotational stiffness; When the expected rotational stiffness is within the secondary stiffness adjustment range, the active compliant joint is reset to the initial position. According to the expert knowledge base II of 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 expected output angle through the servo driver. The stiffness adjustment motor I drives the pinion I to rotate a specified angle. The pinion I engages with the stiffness adjustment gear to drive the stiffness adjustment gear to rotate a specified angle. The stiffness adjustment gear synchronously drives the sector yoke module to offset to the specified position toward the distal end. At the same time, the coupling axial air gap between 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 turned off, the drive motor is started, and the output disk rotates at the expected rotational stiffness.

[0013] The beneficial effects of the present invention are: The present invention uses 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. The joint adopts pure permanent magnetic coupling transmission, which has extremely low maintenance requirements compared to electromagnetic coils, almost no need to replace parts, and reduces the demand for excitation current, so the energy loss is low and the efficiency is high; The gear rack mechanism is cleverly used to achieve the primary stiffness adjustment of the joint. At the same time, the cam and gear integrated structure is used to change the magnetic coupling gap, and the spiral slide groove is used to change the radial position of the fan-shaped magnetic yoke module, so as to achieve the synchronous secondary stiffness adjustment. The variable stiffness joint can quickly and dynamically adjust its response characteristics according to the external load, and the multi-level stiffness adjustment increases the joint stiffness adjustment range, thereby maintaining greater adaptability in the working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of the active compliant transmission joint based on magnetic field control of the present invention; Figure 2 This is an overall exploded view of the active compliant transmission joint based on magnetic field control of 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 the connection plate I and the connection plate II of the present invention; Figure 6 This is a schematic diagram of the first-stage rigidity adjustment transmission process of the present invention; Figure 7 It is a schematic diagram of the two-stage rigidity adjustment transmission process of the present invention; Figure 8 This is a schematic diagram of the output disk structure of the present invention; Fig. 9 This is a schematic diagram of the structure of the coupling plate II of the present invention; Fig.10 This is an exploded view of the assembly shaft module of the present invention; Fig.11 This is a working diagram of the active compliant transmission joint based on magnetic field control of the present invention; Fig.12 A schematic diagram of a primary rigidity adjustment embodiment of an active compliant transmission joint based on magnetic field control of the present invention; Fig.13 A schematic diagram of a two-stage rigidity adjustment embodiment of an active compliant transmission joint based on magnetic field control of the present invention; In the figure: 1. Output module; 2. Stiffness adjustment module; 3. Position drive module; 4. Expert knowledge base I; 5. Position controller; 6. Servo drive; 7. Expert knowledge base II; 1-1. Cylindrical nut group; 1-2. Output disk; 1-3. Permanent magnet baffle group; 1-4. Fan-shaped permanent magnet group 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. Fan-shaped yoke module; 2-1-1. Fan-shaped yoke group I; 2-1-2. Fan-shaped magnet Yoke group II; 2-2, screw I; 2-3, cam guide wall I; 2-4, coupling plate I; 2-5, rigid motor I; 2-6, flange I; 2-7, screw II; 2-8, screw III; 2-9, pinion I; 2-10, rigid gear; 2-11, angular contact ball bearing II; 2-12, assembly shaft module; 2-13, cam guide wall II; 2-14, cam plate; 2-15, sector permanent magnet group II; 2-16, spur rack group; 2-17, coupling plate II; 2-18, nut group II; 2-19, double Head bolt group; 2-20, tension spring group; 2-21, nut group III; 2-22, gear group II; 2-23, gear synchronization shaft; 2-24, gear group III; 2-25, handwheel nut group; 2-26, bearing group I; 2-27, bearing II; 2-28, center hole gear; 2-29, transmission flange; 2-30, screw IV; 2-31, screw V; 2-32, connecting flange; 2-33, rigid motor II; 2-34, screw VI; 2-35, bearing III; 2-36, spiral slide; 2-37, Indexing slide; 2-38, open slot; 2-39, circumferential hole; 2-40, annular groove; 3-1, driving flange; 3-2, hollow harmonic reducer; 3-3, flange II; 3-4, driving motor; 3-5, screw VII; 2-12-1, shaft end retaining ring; 2-12-2, double-layer key sleeve; 2-12-3, circular spline shaft; 2-12-4, segmented shaft; 2-12-5, elastic connection key; 2-12-6, U-shaped spring assembly; 2-12-7, slotted nut; 2-12-8, screw VIII. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] Embodiment 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 driving module 3, wherein the output module 1, the stiffness adjustment module 2 and the position driving module 3 are connected together in sequence; The output module 1 includes an output disk 1-2, a cylindrical nut group 1-1, a permanent magnet baffle group 1-3, a sector permanent magnet group I 1-4, a bolt I 1-5 and a nut I 1-6; the sector permanent magnet group I 1-4 is installed in a built-in groove 1-8 opened in the output disk 1-2, the permanent magnet baffle group 1-3 is fixedly installed in a circumferential slot 1-9 opened in the output disk 1-2 by means of a bolt I 1-5, the cylindrical nut 1-1 and the nut I 1-6 are connected to the bolt I 1-5 in cooperation, and the bolt I 1-5 is prevented from loosening by the cooperation of the cylindrical nut 1-1 and the nut I 1-6, so that the position of the sector permanent magnet group I 1-4 relative to the output disk 1-2 remains unchanged; The stiffness adjustment module 2 includes a connecting plate Ⅰ2-4, a connecting plate Ⅱ2-17, and an assembly shaft module 2-12. The connecting plate Ⅰ2-4 is connected to the connecting plate Ⅱ2-17 by a stud bolt group 2-19, and the stud bolt group 2-19 is provided with a tension spring group 2-20. One end of the assembly shaft module 2-12 is slidingly connected to the center hole spline of the connecting plate Ⅰ2-4, and the other end is connected to the inner ring of the bearing Ⅲ2-35, and the outer ring of the bearing Ⅲ2-35 is interference fit with the center through hole of the connecting plate Ⅱ2-17. The stud bolt group 2-19 and the assembly shaft module 2-12 work together to achieve the change of the axial spacing between the connecting plate Ⅰ2-4 and the connecting plate Ⅱ2-17. 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 spline shaft 2-12-3, a segmented shaft 2-12-4, an elastic connection key 2-12-5, a U-shaped spring assembly 2-12-6, a slotted nut 2-12-7, and a screw VIII 2-12-8; one end of the circular spline shaft 2-12-3 is matched with the inner spline of the double-layer key sleeve 2-12-2, and a shaft end retaining ring 2-12-1 is arranged on the shaft body of the circular spline shaft 2-12-3, and the shaft end retaining ring 2-12-1 is used to prevent the double-layer key sleeve 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 matched with an elastic connection key 2-12-5, the elastic connection key 2-12-5 is convenient for 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 provided with a thread to match the slotted nut 2-12-7, the U-shaped spring group 2-12-6 is matched with the screw VIII 2-12-8 to be installed in the four grooves of the slotted nut 2-12-7 to prevent the slotted nut 2-12-7 from failing when tightened; The output module 1 also includes an angular contact ball bearing Ⅰ1-7, the inner ring of which is interference-mounted on the convex shaft of the connecting disk Ⅰ2-4, and the outer ring of which is fixedly mounted on the central convex shaft of the output disk 1-2 of the output module 1. The angular contact ball bearing Ⅰ1-7 ensures that the connecting disk Ⅰ2-4 and the output disk 1-2 can only rotate relative to each other but cannot move axially. The overall serial arrangement scheme realizes the motion decoupling of the joint position output and the stiffness adjustment. The stiffness adjustment module 2 also includes a fan-shaped permanent magnet group II 2-15, a connecting plate II 2-17, a gear group II 2-22, a rigidity 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 rigidity adjustment motor II 2-33 is fixedly installed with the connecting flange 2-32. The connecting flange 2-32 is installed with the transmission flange 2-29 by screws IV 2-30. The transmission flange 2-29 is installed with screws VI 2-34. The center hole gear 2-28 is installed on the segmented shaft 2-12-4 of the assembly shaft module 2-12 through the bearing Ⅱ2-27, and the grooved nut 2-12-7 contacts the inner ring of the bearing Ⅱ2-27 to realize the axial fixation of the bearing Ⅱ2-27; at the same time, the circumferentially arranged gear set Ⅲ2-24 and the gear set Ⅱ2-22 are installed on the gear synchronization shaft 2-23, and the gear synchronization shaft 2-23 is installed through the bearing set Ⅰ2-26. Installed on the connecting plate Ⅱ2-17, the handwheel nut group 2-25 is installed on the threaded section of the gear synchronization shaft 2-23 to prevent the axial movement of the gear group Ⅲ2-24. The gear group Ⅲ2-24 is meshed with the center hole gear 2-28. The rigid adjustment motor Ⅱ2-33 drives the center hole gear 2-28 to rotate, thereby driving the gear group Ⅲ2-24 to rotate. The gear group Ⅲ2-24 drives the gear group Ⅱ2-22 to rotate through the gear synchronization shaft 2-23; the gear group Ⅱ2-22 is meshed with the spur gear The bar group 2-16 is meshed, and a dividing groove 2-37 is provided on the coupling plate Ⅱ2-17. The sector permanent magnet group Ⅱ2-15 is fixedly mounted on the spur rack group 2-16. The center hole gear 2-28 rotates to drive the gear group Ⅱ2-22 to make the spur rack group 2-16 slide radially on the dividing groove 2-37 of the coupling plate Ⅱ2-17, thereby changing the effective area of ​​the magnetic flux of the sector permanent magnet group Ⅱ2-15 and the sector permanent magnet group Ⅰ1-4, and then changing the magnetic field force to achieve the first-level rigidity adjustment; The stiffness adjustment module 2 also includes a cam disk 2-14, a stiffness adjustment motor Ⅰ2-5, a flange Ⅰ2-6, a pinion Ⅰ2-9, and a stiffness adjustment gear 2-10. The cam disk 2-14 is fixedly mounted on the connecting disk Ⅱ2-17. A cam guide wall Ⅱ2-13 is provided at the center of the cam disk 2-14. The stiffness adjustment gear 2-10 is mounted on the central cam of the connecting disk Ⅰ2-4 through an angular contact ball bearing Ⅱ2-11. A spline groove is provided in the central cam of the connecting disk Ⅰ2-4 to slide 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 disk Ⅱ2-17 is provided with a spline inner hole to cooperate with the spline on the circular spline shaft 2-12-3 of the assembly shaft module 2-12. The flange Ⅰ2-6 is fixed by screws Ⅲ2-8 On the coupling plate Ⅰ2-4, the rigid motor Ⅰ2-5 is fixedly mounted on the flange plate Ⅰ2-6 by means of screws Ⅱ2-7, and the pinion Ⅰ2-9 is mounted on the output end of the rigid motor Ⅰ2-5 and meshes with the rigid gear 2-10 at the same time. The rigid gear 2-10 is provided with a plurality of spiral grooves 2-36 at one end and an arc-shaped cam guide wall Ⅰ2-3 at the other end; each spiral groove 2-36 corresponds one-to-one with the cylindrical pin at the end of the sector yoke group Ⅱ2-1-2, and the rotation of the rigid gear 2-10 drives the sector yoke group Ⅱ2-1-2 to move radially under the action of the spiral groove 2-36, thereby changing the average magnetic permeability of the medium between the sector permanent magnet group Ⅰ1-4 and the sector permanent magnet group Ⅱ2-15, thereby changing the magnetic flux density of the coupling magnetic field. At the same time, when the rigidity adjustment gear 2-10 rotates, the arc cam guide wall Ⅰ2-3 of the rigidity adjustment gear 2-10 interacts with the arc cam guide wall Ⅱ2-13 of the cam disc 2-14 to cause the coupling disc Ⅰ2-4 and the coupling disc Ⅱ2-17 to be axially offset, while the axial distance between the coupling disc Ⅰ2-4 and the output disc 1-2 remains unchanged, so the total coupling magnetic field air gap changes, thereby achieving a change in the magnetic field strength. Here, the adjustment of the magnetic flux density of the coupling magnetic field and the magnetic coupling air gap by the rigidity adjustment motor Ⅰ2-5 will be carried out synchronously to achieve secondary rigidity adjustment; The stiffness adjustment module 2 also includes a sector yoke module 2-1 and a coupling plate Ⅰ2-4, and a graduated through-type slide groove is opened on the coupling plate Ⅰ2-4. The sector yoke module 2-1 includes a sector yoke group Ⅰ2-1-1 and a sector yoke group Ⅱ2-1-2. Each sector yoke group Ⅰ2-1-1 and sector yoke group Ⅱ2-1-2 are symmetrically fixed and installed in pairs through four screws Ⅰ2-2 to form a synchronous radially moving sector yoke module 2-1, and is installed on the graduated through-type slide groove of the coupling plate Ⅰ2-4 through a cylindrical pin at the root of the sector yoke group Ⅱ2-1-2. The sector yoke module 2-1 can slide radially on the graduated through-type slide groove of the coupling 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, and the output end of the hollow harmonic reducer 3-2 is connected to the drive flange 3-1 through the screw VII 3-5; the other end of the drive flange 3-1 is fixedly mounted on the annular groove 2-40 opened on the connecting plate II 2-17 by the screw VI 2-34, so that the position drive module 3 is connected to the stiffness adjustment module 2, and the stiffness adjustment motor II 2-33 is fixed on the arc groove of the drive flange 3-1 by the screw V 2-31; The rigid-adjusting motor II 2-33 is mounted on the driving flange 3-1 by means of screws 2-31, and the tail of the rigid-adjusting motor II 2-33 is embedded in the hollow harmonic reducer 3-2.

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

[0018] The coupling plate II 2-17 is provided with eight uniform dividing grooves 2-37, and the dividing grooves 2-37 are provided with open grooves 2-38 to enable the gear set II 2-22 and the ruler rack set 2-16 to mesh with each other. The eight ruler rack sets 2-16 are installed in the dividing grooves 2-37 for radial sliding, and the sector 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 uniformly installed on one end of the eight gear synchronization shafts 2-23. The eight gear synchronization shafts 2-23 are uniformly installed in the annular holes 2-39 opened in the coupling plate II 2-17 through the bearing set I 2-26, and the gear set III 2-24 is installed on the other end of the eight gear synchronization shafts 2-23.

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

[0020] The center angle of the eight spiral grooves 2-36 provided on the steel adjustment gear 2-10 is 90°.

[0021] The inclination of the cam guide wall I2-3 set on the rigid-adjusting gear 2-10 and the cam guide wall II2-13 set on the cam disc 2-14 are both 45°, and the circumferential angles of the cam guide wall I2-3 and the cam guide wall II2-13 are both 180°; observed from the side of the spiral groove 2-36, when the rigid-adjusting gear 2-10 rotates 90° counterclockwise from the initial position, the axial distance between the connecting disc I2-4 and the connecting disc II2-17 is the smallest, and the fan-shaped yoke module 2-1 is located at the distal end. At this time, the magnetic permeability of the magnetic medium of the coupling magnetic field is the largest and the magnetic coupling gap is the smallest, and the output stiffness of the active compliant transmission joint is the largest under the secondary stiffness.

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

[0023] Embodiment three, as Fig.11 As shown, a working method of an active compliant transmission joint based on magnetic field regulation includes an active compliant transmission joint, and the method includes the following steps: Step 1: Define the adjustment method and adjustment range of the first-level rigidity adjustment The first-level rigidity adjustment mainly determines the relationship between the rotation range of the rigidity adjustment motor Ⅱ2-33 and the radial slip range of the fan-shaped permanent magnet group Ⅱ2-15, and then determines the relationship between the rotation range of the rigidity 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 rigidity-adjusting motor Ⅰ2-5 and the rigidity-adjusting motor Ⅱ2-33 to make the active compliant transmission joint located at the initial position; b. The sector permanent magnet group II 2-15 is installed on the spur rack group 2-16. The radial slip range of the sector permanent magnet group II 2-15 can be obtained by measuring the radial slip range of the spur rack group 2-16 on the ruler groove on the coupling plate I 2-4. The gear group II 2-22 is meshed with the spur rack group 2-16. The angular range of the gear group II 2-22 is determined according to the measured slip range of the sector permanent magnet group II 2-15. The gear group II 2-22 and the gear group III 2-24 are coaxially driven, and the relationship between the radial slip range of the sector permanent magnet group II 2-15 and the angular range of the gear group III 2-24 can be obtained. c. Gear set III 2-24 meshes with the center hole gear 2-28, and the rotation angle range of the center hole gear 2-28 is determined according to the fixed gear transmission ratio relationship. The output end of the rigid motor II 2-33 is fixedly installed with the connecting flange 2-32 to directly drive the center hole gear 2-28, and the output rotation angle range of the rigid motor II 2-33 is determined according to the rotation angle range of the center hole gear 2-28; d. Draw the relationship curve between the rotation angle of the rigid motor Ⅱ2-33 and the radial slip range of the sector permanent magnet group Ⅰ1-4, and perform curve fitting based on the least squares method to determine the relationship between the rotation angle of the rigid motor Ⅱ2-33 and the radial slip of the sector permanent magnet group Ⅱ2-15; e. Using Maxwell simulation, perform step scanning within the radial slip range of the sector permanent magnet group II 2-15, measure the output torque of the compliant transmission joint at different radial slip positions of the sector permanent magnet group II 2-15, use the field quantity calculator to perform angle derivative processing on the curve data, and obtain the relationship between the rotation range of the rigidity adjustment motor II 2-33 and the output stiffness of the active compliant transmission joint, that is, calibrate the adjustment method and adjustment range of the first-level rigidity adjustment of the active compliant transmission joint, and record the results in the expert knowledge base I4; Step 2: Define the adjustment method and adjustment range of the secondary rigidity adjustment The secondary rigidity adjustment mainly measures the relationship between the rotation range of rigidity adjustment motor Ⅰ2-5 and the output rigidity of active compliant transmission joint, which is specifically reflected in the relationship between the rotation angle of rigidity adjustment motor Ⅰ2-5 and the radial displacement range of fan-shaped magnetic yoke module 2-1 and the axial air gap between fan-shaped permanent magnet group Ⅱ2-15 and fan-shaped permanent magnet group Ⅰ1-4. a. Control the rigidity-adjusting motor Ⅰ2-5 and the rigidity-adjusting motor Ⅱ2-33 to make the active compliant transmission joint located at the initial position; b. The rotation of the rigid gear 2-10 will synchronously affect the radial displacement of the sector 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, drive the rigid gear 2-10 to rotate a fixed step angle, measure the radial displacement of the sector yoke module 2-1, and at the same time, measure the axial distance between the sector permanent magnet group II 2-15 and the sector permanent magnet group I 1-4, and determine the rotation angle range of the rigid gear 2-10 based on the radial displacement range of the sector yoke module 2-1 and the axial distance range between the sector permanent magnet group II 2-15 and the sector permanent magnet group I 1-4. And determine the relationship between the rotation angle of the rigid gear 2-10 and the axial air gap length of the sector permanent magnet group II 2-15 and the sector permanent magnet group I 1-4, as well as the relationship between the rotation angle of the rigid gear 2-10 and the radial displacement of the sector yoke module 2-1, and determine the relationship between the change in the axial air gap length of the sector permanent magnet group II 2-15 and the sector permanent magnet group I 1-4 and the radial displacement of the sector yoke module 2-1; c. The pinion Ⅰ2-9 meshes with the rigid adjustment gear 2-10, and the rotation angle range of the pinion Ⅰ2-9 is determined according to the fixed gear transmission ratio formula; d. Using Maxwell simulation, according to the relationship between the change in the axial air gap length of the fan-shaped permanent magnet group II 2-15 and the fan-shaped permanent magnet group I 1-4 and the radial displacement of the fan-shaped yoke module 2-1 determined in step 3b, perform synchronous multiple scans on the radial displacement of the fan-shaped yoke module 2-1 and the axial air gap length of the fan-shaped permanent magnet group II 2-15 and the fan-shaped permanent magnet group I 1-4, measure the output torque curve of the active compliant transmission joint under different radial positions of the fan-shaped yoke module 2-1 and different axial air gaps of the fan-shaped permanent magnet group II 2-15 and the fan-shaped permanent magnet group I 1-4, use the field quantity calculator to perform angle partial derivative processing on the curve data, and obtain the relationship between the rotation range of the rigidity-adjusting motor I 2-5 and the output stiffness of the active compliant transmission joint, that is, calibrate the adjustment method and adjustment range of the secondary rigidity adjustment, and record the results in the expert knowledge base II 7; Step 3: Determine the expected value of the rotational stiffness of the output disk 1-2 according to actual use requirements, and determine whether the active compliant joint enables the first-level stiffness adjustment or the second-level stiffness adjustment according to the expert knowledge base Ⅰ4 and the expert knowledge base Ⅱ7 recorded in steps 2 and 3; like Fig.12 As shown, 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 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 through the servo driver 6, and the stiffness adjustment motor Ⅱ2-33 drives the center hole gear 2-28 to output the specified angle, and the center hole gear 2-28 meshes with the gear set Ⅲ2-24 to drive the 8-gear synchronous shaft 2-23 to rotate the gear set Ⅱ2-22 To the desired angle, at this time, the spur rack group 2-16 meshing with the gear group Ⅱ2-22 is driven by the gear group Ⅱ2-22 to slide to the specified displacement in the indexing slot, and 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 rigidity adjustment work is completed, the rigidity adjustment motor Ⅱ2-33 is powered off and braked, and the drive motor 3-4 is started, and the output disk 1-2 rotates at the desired rotational rigidity; like Fig.13As shown, when the expected rotational stiffness is within the secondary stiffness adjustment range, the active compliant joint is reset to the initial position, and 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 expected output angle through the servo driver 6, and the stiffness adjustment motor I2-5 drives the pinion I2-9 to rotate a specified angle, and the pinion I2-9 engages with the stiffness adjustment gear 2-10 to drive the stiffness adjustment gear 2-10 to rotate a specified angle, and the stiffness adjustment gear 2-10 synchronously drives the sector yoke module 2-1 to offset to the specified position toward the distal end, and at the same time, the coupling axial air gap 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 turned off, and the drive motor 3-4 is started, and the output disk 1-2 rotates at the expected rotational stiffness.

[0025] The fan-shaped permanent magnet group Ⅰ1-4 is fixed on the output disk 1-2 of the output module 1 to form a coupling transmission with the fan-shaped permanent magnet group Ⅱ2-15 fixed on the connection disk Ⅱ2-17. The rigidity-adjusting motor Ⅰ2-5 is fixed on the connection disk Ⅰ2-4 to realize the radial displacement of the iron yoke and the change of the permanent magnet air gap. The rigidity-adjusting motor Ⅱ2-33 is fixed on the connection disk Ⅱ2-17 to realize the radial movement of the fan-shaped permanent magnet group Ⅱ2-15, thereby changing the effective area of ​​the magnetic flux. By controlling the rigidity-adjusting motor, the effective area and magnetic flux density of the fan-shaped permanent magnet group Ⅰ1-4 and the fan-shaped permanent magnet group Ⅱ2-15 can be effectively changed, thereby changing the magnetic field force to change the output stiffness. The expert knowledge base Ⅰ4 and the expert knowledge base Ⅱ7 are used to make the rigidity-adjusting motor Ⅰ2-5 and the rigidity-adjusting motor Ⅱ2-33 output the specified 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 invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0027] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An active compliant transmission joint based on magnetic field control, comprising an output module (1), a stiffness adjustment module (2) and a position driving module (3), characterized in that: The output module (1), the stiffness adjustment module (2) and the position driving module (3) are connected together in sequence; The output module (1) comprises an output disk (1-2), a cylindrical nut group (1-1), a permanent magnet baffle group (1-3), a sector permanent magnet group I (1-4), a bolt I (1-5) and a nut I (1-6); the sector permanent magnet group I (1-4) is installed in a built-in groove (1-8) provided in the output disk (1-2); the permanent magnet baffle group (1-3) is fixedly installed in a circumferential slot (1-9) provided in the output disk (1-2) by means of the bolt I (1-5); the cylindrical nut (1-1) and the nut I (1-6) are connected to the bolt I (1-5) in cooperation; The stiffness adjustment module (2) comprises a coupling plate I (2-4), a coupling plate II (2-17), and an assembly shaft module (2-12); the coupling plate I (2-4) and the coupling plate II (2-17) are connected via a stud bolt group (2-19), and the stud bolt group (2-19) is provided with a tension spring group (2-20); one end of the assembly shaft module (2-12) is spline-slidably connected to the center hole of the coupling plate I (2-4), and the other end is connected to the inner ring of the bearing III (2-35), and the outer ring of the bearing III (2-35) is interference-fitted with the center through hole of the coupling plate II (2-17); The assembled shaft module (2-12) comprises a shaft end retaining ring (2-12-1), a double-layer key sleeve (2-12-2), a circular spline shaft (2-12-3), a segmented shaft (2-12-4), an elastic connection key (2-12-5), a U-shaped spring assembly (2-12-6), a slotted nut (2-12-7), and a screw VIII (2-12-8); one end of the circular spline shaft (2-12-3) cooperates with the inner spline of the double-layer key sleeve (2-12-2), and the circular spline A shaft end retaining ring (2-12-1) is arranged on the shaft body of the shaft (2-12-3); the other end of the circular spline shaft (2-12-3) is matched with one end of the segmented shaft (2-12-4) by using an elastic connection key (2-12-5); the other end of the segmented shaft (2-12-4) is provided with a thread matched with a slotted nut (2-12-7); the U-shaped spring assembly (2-12-6) is matched with a screw VIII (2-12-8) and installed in four grooves of the slotted nut (2-12-7); The output module (1) further comprises an angular contact ball bearing I (1-7), the inner ring of the angular contact ball bearing I (1-7) being interference-mounted on the convex shaft of the coupling disk I (2-4), and the outer ring of the angular contact ball bearing I (1-7) being fixedly mounted on the central convex shaft of the output disk (1-2) of the output module (1); The stiffness adjustment module (2) further comprises a sector permanent magnet group II (2-15), a coupling 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 mounted on a connecting flange (2-32); the connecting flange (2-32) is mounted on a transmission flange (2-29) via screws IV (2-30); the transmission method The flange (2-29) is mounted on the center hole gear (2-28) through a 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 threaded position through a bearing II (2-27); the grooved nut (2-12-7) contacts the inner ring of the bearing II (2-27) to achieve axial fixation of the bearing II (2-27); at the same time, the circumferentially arranged gear set III (2-24) and the gear set II (2-22) are mounted on the gear set. The handwheel nut group (2-25) is installed on the threaded section of the gear synchronization shaft (2-23); the gear synchronization shaft (2-23) is installed on the connecting plate II (2-17) through the bearing group I (2-26); the handwheel nut group (2-25) is installed on the threaded section of the gear synchronization shaft (2-23); the gear group III (2-24) is meshed with the center hole gear (2-28); the rigidity regulating motor II (2-33) drives the center hole gear (2-28) to rotate, thereby driving the gear group III (2-24) to rotate; the gear group III (2-24) is synchronized by the gear The shaft (2-23) drives the gear set II (2-22) to rotate; the gear set II (2-22) meshes with the spur rack set (2-16); a graduation groove (2-37) is provided on the coupling disk II (2-17); the sector permanent magnet set II (2-15) is fixedly mounted on the spur rack set (2-16); the center hole gear (2-28) rotates to drive the gear set II (2-22) to make the spur rack set (2-16) radially slide on the graduation groove (2-37) of the coupling disk II (2-17); The stiffness adjustment module (2) further comprises a cam disc (2-14), a stiffness adjustment motor I (2-5), a flange disc I (2-6), a pinion I (2-9), and a stiffness adjustment gear (2-10). The cam disc (2-14) is fixedly mounted on a coupling disc II (2-17). The stiffness adjustment gear (2-10) is mounted on a central cam shaft of the coupling disc I (2-4) via an angular contact ball bearing II (2-11). The central cam shaft of the coupling disc I (2-4) has a spline groove in it that is slidably connected to an outer spline of a double-layer key sleeve (2-12-2) in the assembly shaft module (2-12). At the same time, the coupling disc II (2-17) has a spline inner hole that is slidably connected to an outer spline of the assembly shaft module (2-12). The circular spline shaft (2-12-3) is spline-matched; the flange plate I (2-6) is fixed on the connection plate I (2-4) by means of screws III (2-8); the adjustable motor I (2-5) is fixedly mounted on the flange plate I (2-6) by means of screws II (2-7); the pinion gear I (2-9) is mounted on the output end of the adjustable motor I (2-5) and is meshed with the adjustable gear (2-10); a plurality of spiral grooves (2-36) are provided at one end of the adjustable gear (2-10) and an arc-shaped cam guide wall I (2-3) is provided at the other end; each spiral groove (2-36) is matched with a cylindrical pin on the end of the sector yoke group II (2-1-2) in a one-to-one correspondence; The stiffness adjustment module (2) further comprises a sector yoke module (2-1) and a coupling plate I (2-4), wherein the coupling plate I (2-4) is provided with a graduated through-type slide groove, and the sector yoke module (2-1) comprises a sector yoke group I (2-1-1) and a sector yoke group II (2-1-2), wherein each of the sector yoke groups I (2-1-1) and sector yoke groups II (2-1-2) are symmetrically fixedly mounted on the graduated through-type slide groove in pairs by four screws I (2-2); The position drive module (3) comprises 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) via the flange II (3-3); the output end of the hollow harmonic reducer (3-2) is connected to the drive flange (3-1) via a screw VII (3-5); the other end of the drive flange (3-1) is fixedly mounted on an annular groove (2-40) provided on a connecting plate II (2-17) via a 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 to the arc-shaped groove of the drive flange (3-1) via a 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: The sector-shaped permanent magnet group I (1-4) and the sector-shaped permanent magnet group II (2-15) are each provided 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 coupling plate II (2-17) is provided with eight uniform indexing grooves (2-37), and the indexing grooves (2-37) are provided with opening grooves (2-38) so that the gear set II (2-22) and the ruler rack set (2-16) can mesh with each other. The eight ruler rack sets (2-16) are installed in the indexing grooves (2-37) to slide radially, and the sector 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 uniformly installed on one end of the eight gear synchronization shafts (2-23). ​​The eight gear synchronization shafts (2-23) are uniformly installed in the annular holes (2-39) opened in the coupling plate II (2-17) through the bearing set I (2-26), and the gear set III (2-24) is installed on the other end of the eight gear synchronization shafts (2-23).

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 the 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) contacts the highest point of the inclined surface of the cam guide wall II (2-13), 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 center angle of the eight spiral grooves (2-36) provided on the rigidity-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 inclination of the cam guide wall I (2-3) provided on the rigid adjustment gear (2-10) and the cam guide wall II (2-13) provided on the cam shaft plate (2-14) are both 45 degrees, and the circumferential angles of the cam guide wall I (2-3) and the cam guide wall II (2-13) are both 180 degrees.

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 the cam guide wall II (2-13) are always in contact under the tensile force of the tension spring group (2-20).

8. A working method of an active compliant transmission joint based on magnetic field control according to any one of claims 1 to 7, comprising an active compliant transmission joint, characterized in that: The working method comprises the following steps: Step 1: Define the adjustment method and adjustment range of the first-level rigidity adjustment The first-level rigidity adjustment mainly determines the relationship between the rotation range of the rigidity adjustment motor II (2-33) and the radial slip range of the fan-shaped permanent magnet group II (2-15), and then determines the relationship between the rotation range of the rigidity 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 rigidity adjustment motor I (2-5) and the rigidity adjustment motor II (2-33) to make the active compliant transmission joint located at the initial position; b. The sector permanent magnet group II (2-15) is installed on the spur rack group (2-16). The radial slip range of the spur rack group (2-16) on the ruler groove is measured on the coupling plate I (2-4), and the radial slip range of the sector permanent magnet group II (2-15) can be obtained. The gear group II (2-22) is meshed with the spur rack group (2-16). The rotation angle range of the gear group II (2-22) is determined according to the measured slip range of the sector permanent magnet group II (2-15). The gear group II (2-22) and the gear group III (2-24) are coaxially driven, and the relationship between the radial slip range of the sector permanent magnet group II (2-15) and the rotation angle of the gear group III (2-24) is obtained. c. The gear set III (2-24) meshes with the center hole gear (2-28), and the rotation angle range of the center hole gear (2-28) is determined according to the fixed gear transmission ratio relationship. The output end of the rigid motor II (2-33) is fixedly installed with the connecting flange (2-32) to directly drive the center hole gear (2-28), and the output rotation angle range of the rigid motor II (2-33) is determined according to the rotation angle range of the center hole gear (2-28); d. Draw the relationship curve between the rotation angle of the rigid motor II (2-33) and 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 rigid motor II (2-33) and the radial slip of the sector permanent magnet group II (2-15); e. Using Maxwell simulation, perform step scanning within the radial slip range of the fan-shaped permanent magnet group II (2-15), measure the output torque of the compliant transmission joint at different radial slip positions of the fan-shaped permanent magnet group II (2-15), use the field quantity calculator to perform angle derivative processing on the curve data, and obtain the relationship between the rotation range of the rigidity adjustment motor II (2-33) and the output stiffness of the active compliant transmission joint, that is, calibrate the adjustment method and adjustment range of the first-level rigidity adjustment of the active compliant transmission joint, and record the results in the expert knowledge base I (4); Step 2: Define the adjustment method and adjustment range of the secondary rigidity 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, which is specifically reflected in the relationship between the rotation angle of the stiffness adjustment motor I (2-5) and the radial displacement range of the fan-shaped magnetic yoke module (2-1) and the axial air gap between the fan-shaped permanent magnet group II (2-15) and the fan-shaped permanent magnet group I (1-4); a. Control the rigidity adjustment motor I (2-5) and the rigidity adjustment motor II (2-33) to make the active compliant transmission joint located at the initial position; b. The rotation of the rigid adjustment gear (2-10) will synchronously affect the radial displacement of the sector 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), drive the rigid adjustment gear (2-10) to rotate a fixed step angle, measure the radial displacement of the sector yoke module (2-1), and at the same time, measure the axial distance between the sector permanent magnet group II (2-15) and the sector permanent magnet group I (1-4), and combine the radial displacement range of the sector yoke module (2-1) and the axial distance between the sector permanent magnet group II (2-15) and the sector permanent magnet group I (1-4). The axial distance range of the permanent magnet group I (1-4) is used to determine the rotation angle range of the rigid gear (2-10), and the relationship between the rotation angle of the rigid gear (2-10) and the axial air gap length of the sector permanent magnet group II (2-15) and the sector permanent magnet group I (1-4), as well as the relationship between the rotation angle of the rigid gear (2-10) and the radial displacement of the sector yoke module (2-1), and the relationship between the change in the axial air gap length of the sector permanent magnet group II (2-15) and the sector permanent magnet group I (1-4) and the radial displacement of the sector yoke module (2-1); c. The pinion I (2-9) meshes with the rigid gear (2-10), and the rotation angle range of the pinion I (2-9) is determined according to the fixed gear transmission ratio formula; d. Using Maxwell simulation, according to the relationship between the change in the axial air gap length of the fan-shaped permanent magnet group II (2-15) and the radial displacement of the fan-shaped yoke module (2-1) determined in step 3 (b), the radial displacement of the fan-shaped yoke module (2-1) and the axial air gap length of the fan-shaped permanent magnet group II (2-15) and the fan-shaped permanent magnet group I (1-4) are synchronously scanned multiple times to measure the output torque curve of the active compliant transmission joint under different radial positions of the fan-shaped yoke module (2-1) and different axial air gaps of the fan-shaped permanent magnet group II (2-15) and the fan-shaped permanent magnet group I (1-4). The curve data is processed by angle derivation using a field quantity calculator to obtain the relationship between the rotation range of the rigidity-adjusting 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 rigidity adjustment, and the results are recorded in the expert knowledge base II (7); Step 3: Determine the expected value of the rotational stiffness of the output disk (1-2) according to actual use requirements, and determine whether to enable the first-level stiffness adjustment or the second-level stiffness adjustment of the active compliant joint according to the expert knowledge base I (4) and the expert knowledge base II (7) recorded in steps 2 and 3; 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), and the stiffness adjustment motor II (2-33) drives the center hole gear (2-28) to output a specified angle, and the center hole gear (2-28) meshes with the gear set III (2-24) to drive the 8-gear synchronous shaft (2-23) to rotate the gear set II (2-22) to The desired angle is reached. At this time, the spur rack group (2-16) meshing with the gear group II (2-22) is driven by the gear group II (2-22) to slide in the indexing slot to a specified displacement. The sector permanent magnet group II (2-15) is fixed at the rear end of the spur rack group (2-16) and radially slides synchronously with the spur rack group (2-16), thereby changing the centering area of ​​the sector permanent magnet group II (2-15) and the sector permanent magnet group I (1-4). After the rigidity adjustment work is completed, the rigidity adjustment motor II (2-33) is powered off and braked, and the drive motor (3-4) is started, and the output disk (1-2) rotates at the desired rotational rigidity. When the desired rotational stiffness is within the secondary stiffness adjustment range, 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 rotation angle through the servo driver (6). The stiffness adjustment motor I (2-5) drives the pinion I (2-9) to rotate to 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 to a specified angle. The stiffness adjustment gear (2-10) synchronously drives the fan-shaped magnetic yoke module (2-1) to shift to a specified position toward the distal end. At the same time, the coupling axial air gap between the fan-shaped permanent magnet group II (2-15) and the fan-shaped permanent magnet group I (1-4) changes. After the stiffness adjustment work is completed, the stiffness adjustment motor I (2-5) and the brake are powered off, and the drive motor (3-4) is started, and the output disk (1-2) rotates at the desired rotational stiffness.

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