A variable stiffness joint for flexible robots based on hybrid electromagnets

Abstract

A variable stiffness joint for a flexible robot based on a hybrid electromagnet comprises a motor, a hybrid electromagnet fixing sleeve, a hybrid electromagnet, a joint housing, electrical pure iron and a motor support frame; the hybrid electromagnet fixing sleeve, the hybrid electromagnet and the electrical pure iron are located in the joint housing; wherein the joint stiffness adjustment part adopts the combined action of the hybrid electromagnet and the spring sheet, and has the advantages of fast stiffness adjustment response speed, no delay, no lag, etc. The magnetic force and stiffness can be maintained in the non-powered state, and the joint has energy-saving characteristics. At the same time, the joint also has the characteristics of simple movement form, simple manufacturing, and simple operation. The magnetic flux in the joint magnetic circuit system is jointly determined by the current in the permanent magnet and the excitation coil (copper coil). Therefore, by changing the magnitude and direction of the current in the excitation coil, the magnetic flux in the magnetic circuit system can be increased or decreased, that is, the joint stiffness can be increased or decreased, and the joint stiffness change is nonlinear.

Description

Technical Field

[0001] The invention belongs to the technical field of flexible robots, and in particular relates to a variable stiffness joint for a flexible robot based on a hybrid electromagnet, and is particularly suitable for the construction of a flexible serial variable stiffness robot. Background Art

[0002] Robot technology has been widely used in industrial production, medical services, humanities and entertainment, and contact with people has become frequent and close. Therefore, the safety issue of human-machine interaction is becoming a hot topic of concern. Flexible variable stiffness robots are a type of flexible robot with adjustable stiffness, which is different from traditional rigid robots. Due to its adjustable stiffness, it can greatly improve human-machine safety and environmental adaptability. Flexible variable stiffness robots involve disciplines such as bionics, robotics, materials science, and control science, and have become an important direction for the development of robots in the future. Whether from the perspective of safety during human-robot interaction or the flexibility of operation during human-machine collaboration, the study of variable stiffness joints for flexible robots has practical application value and research value.

[0003] The variable stiffness capability of the variable stiffness joint for flexible robots based on hybrid electromagnets mainly depends on the variable stiffness performance under the combined action of the hybrid electromagnet and the spring sheet. Therefore, designing a variable stiffness joint with small size, light weight, and rapid response to joint stiffness adjustment is of great significance for solving key issues such as human-machine safety, improving dynamic characteristics and trajectory tracking of the new generation of robots. In recent years, the performance of permanent magnetic materials has been greatly improved, especially rare earth permanent magnetic materials with high magnetic energy per unit volume and excellent performance. Therefore, it is becoming a hot topic to directly construct variable stiffness joints by using the nonlinear characteristics of mechanics and stiffness changes between permanent magnets. However, no such reports have been seen so far. Summary of the invention

[0004] Purpose of the invention:

[0005] The present invention provides a variable stiffness joint for a flexible robot based on a hybrid electromagnet, and its purpose is to provide a variable stiffness joint with simple movement form, simple manufacturing, simple operation, and rapid joint stiffness adjustment response, so as to solve the problems existing in the past.

[0006] Technical solution:

[0007] A variable stiffness joint for a flexible robot based on a hybrid electromagnet comprises a motor A, a hybrid electromagnet fixing sleeve 6, a hybrid electromagnet, a joint housing 7, electrical pure iron 8 and a motor support frame 10; the hybrid electromagnet fixing sleeve 6, the hybrid electromagnet and the electrical pure iron 8 are located in the joint housing 7;

[0008] The motor support frame 10 is sleeved outside the motor A, the motor output shaft 1 passes through the front end of the motor support frame 10, the hybrid electromagnet is installed at the rear end of the hybrid electromagnet fixed sleeve 6, the hybrid electromagnet is located between the hybrid electromagnet fixed sleeve 6 and the electrical pure iron 8, and the hybrid electromagnet fixed sleeve 6 is fixedly connected to the motor output shaft 1;

[0009] The front end of the motor support frame 10 extends into the joint housing 7 , and the electrical pure iron 8 is sleeved on the portion of the motor support frame 10 extending into the joint housing 7 .

[0010] The joint further comprises a spring sheet 5 which is also located in the joint housing 7 . The spring sheet 5 is fixedly sleeved on the motor shaft 1 via a spring sheet fixing sleeve 14 . The outer end of the spring sheet 5 is embedded in a rotation-stop groove 7 - 1 on the inner wall of the joint housing 7 .

[0011] The hybrid electromagnet includes a plastic bobbin 19, a copper coil 20, a permanent magnet 22 and an iron core 25; the iron core 25 is symmetrically arranged on both sides of the permanent magnet 22, the plastic bobbin 19 is sleeved on the iron core 25 and consolidated with the iron core 25, the copper coil 20 is sleeved on the plastic bobbin 19 and arranged coaxially with the plastic bobbin 19, the plastic bobbin 19, the copper coil 20, the permanent magnet 22 and the iron core 25 form a whole, and the permanent magnet 22 and the iron core 25 are connected to the hybrid electromagnet fixed sleeve 6.

[0012] Two fixed baffles 23 are fixed to the iron core 25 and the permanent magnet 22 at the front and rear sides of the bottom of the iron core 25 and the permanent magnet 22 , and the iron core 25 and the permanent magnet 22 are fixed to the hybrid electromagnet fixed sleeve 6 by the fixed baffles 23 .

[0013] The spring leaves 5 are composed of two pieces, and the two spring leaves 5 are symmetrically arranged with the motor output shaft 1 as the symmetry axis. The outer ends of the two spring leaves 5 are embedded in the anti-rotation groove 7 - 1 on the inner wall of the joint housing 7 .

[0014] A joint end cover 4 is provided at the front end of the joint housing 7 . The joint end cover 4 and the motor output shaft 1 are concentrically arranged through a small tapered roller bearing 2 . The joint end cover 4 is fixed to the joint housing 7 .

[0015] The hybrid electromagnet is concentrically fixed to the motor output shaft 1 through a hybrid electromagnet fixing sleeve 6 . The hybrid electromagnet is divided into two groups, and the two groups of hybrid electromagnets are symmetrically arranged at both sides of the motor output shaft 1 at equal distances.

[0016] The end surface of the motor reducer B is fixed to the motor support frame 10 by three motor support frame fastening bolts 17 .

[0017] The inner ring of the large tapered roller bearing 11 is matched with the outer wall of the motor support frame 10 , and the outer ring of the large tapered roller bearing 11 is matched with the electrical pure iron 8 .

[0018] The bottom surface of the electrical pure iron 8 is fixed to the bottom surface of the joint housing 7; the bottom surface of the motor A is matched with the encoder 9.

[0019] Advantages and effects:

[0020] The variable stiffness joint for the flexible robot based on the hybrid electromagnet of the present invention is jointly acted by the hybrid electromagnet and the spring sheet, and has the advantages of fast stiffness adjustment response speed and energy saving.

[0021] The present invention comprises: a motor, a small tapered roller bearing, a joint end cover fastening bolt assembly, a joint end cover, a spring sheet, a hybrid electromagnet fixing sleeve, a joint housing, electrical pure iron, an encoder, a motor support frame, a large tapered roller bearing, an electrical pure iron fastening bolt assembly, a spring sheet fastening nut, a spring sheet fixing sleeve, a hybrid electromagnet sleeve bolt assembly, a hybrid electromagnet sleeve nut assembly, a motor support frame fastening bolt assembly, a spring sheet fastening bolt, a plastic bobbin, a copper coil, a hybrid electromagnet fastening bolt, a permanent magnet, a fixed baffle, a hybrid electromagnet fastening nut, an iron core and other components.

[0022] The two spring sheets are symmetrically arranged in the matching joint housing, the outer ends of the spring sheets are embedded in the anti-rotation groove 7-1 on the inner wall of the joint housing 7, and the spring sheets are fixed to the motor shaft by the spring sheet fixing sleeve through the spring sheet fastening bolt and the spring sheet fastening nut. The spring sheet fixing sleeve is fixed with the motor shaft.

[0023] The electrical pure iron is fixed to the bottom surface of the joint housing by 4 fastening bolts, leaving an air gap of 1mm with the hybrid electromagnet.

[0024] The hybrid electromagnets are symmetrically arranged at equal distances on both sides of the motor shaft. The hybrid electromagnets are composed of permanent magnets, iron cores, plastic bobbins, copper coils, fixed baffles, hybrid electromagnet fastening bolts, hybrid electromagnet fastening nuts, hybrid electromagnet fixed sleeves, hybrid electromagnet sleeve bolt assemblies, hybrid electromagnet sleeve nut assemblies, etc.

[0025] The iron core is symmetrically arranged on both sides of the permanent magnet, the plastic bobbin is fixed to the iron core, the copper coil is coaxially arranged with the plastic bobbin, and the front and rear fixed baffles are fixed at the bottom of the iron core and the permanent magnet by hybrid electromagnet fastening bolts and hybrid electromagnet fastening nuts.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. A variable stiffness joint for a flexible robot based on a hybrid electromagnet is designed, in which the joint stiffness adjustment part adopts the combined action of a hybrid electromagnet and a spring sheet. Since the hybrid electromagnet is used to adjust the joint stiffness, it has the advantages of fast stiffness adjustment response speed, no delay, and no lag.

[0028] 2. Since the hybrid electromagnet and the spring sheet work together to control the joint stiffness, the magnetic force and stiffness can be maintained in the non-powered state, which has energy-saving characteristics. The present invention also has the characteristics of simple movement form, simple manufacturing, and simple operation.

[0029] 3. The magnetic flux in the joint magnetic circuit system (hybrid electromagnet) is jointly determined by the current in the permanent magnet and the excitation coil (copper coil). Therefore, by changing the magnitude and direction of the current in the excitation coil, the magnetic flux in the magnetic circuit system can be increased or decreased, that is, the joint stiffness can be increased or decreased, and the change in the joint stiffness is nonlinear. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 The cross-sectional diagram of the variable stiffness joint structure for a flexible robot based on a hybrid electromagnet;

[0032] Figure 2 Schematic diagram of the explosion of the variable stiffness joint structure for the flexible robot based on hybrid electromagnet;

[0033] Figure 3 It is the principle schematic diagram of the variable stiffness part;

[0034] Figure 4 It is a schematic diagram of the structure of the hybrid electromagnet;

[0035] Figure 5 It is a cross-sectional schematic diagram of the hybrid electromagnet structure;

[0036] 1. In the figure, 1 is the motor output shaft, 2 is the small tapered roller bearing, 3 is the joint end cover fastening bolt assembly, 4 is the joint end cover, 5 is the spring sheet, 6 is the hybrid electromagnet fixing sleeve, 7 is the joint housing, 8 is the electrical pure iron, 9 is the encoder, 10 is the motor support frame, 11 is the large tapered roller bearing, 12 is the electrical pure iron fastening bolt assembly, 13 is the spring sheet fastening nut, 14 is the spring sheet fixing sleeve, 15 is the hybrid electromagnet sleeve bolt assembly, 16 is the hybrid electromagnet sleeve nut assembly, 17 is the motor support frame fastening bolt assembly, 18 is the spring sheet fastening bolt, 19 is the plastic spool, 20 is the copper coil, 21 is the hybrid electromagnet fastening bolt, 22 is the permanent magnet, 23 is the fixed baffle, 24 is the hybrid electromagnet fastening nut, 25 is the iron core. DETAILED DESCRIPTION

[0037] A variable stiffness joint for a flexible robot based on a hybrid electromagnet comprises a motor A, a hybrid electromagnet fixing sleeve 6, a hybrid electromagnet, a joint housing 7, electrical pure iron 8 and a motor support frame 10; the hybrid electromagnet fixing sleeve 6, the hybrid electromagnet and the electrical pure iron 8 are located in the joint housing 7;

[0038] The motor support frame 10 is sleeved outside the motor A, and the motor output shaft 1 passes through the front end of the motor support frame 10. Figure 1 The upper end of the mixing electromagnet is installed at the rear end of the mixing electromagnet fixed sleeve 6. Figure 1 At the lower end of the hybrid electromagnet fixed sleeve 6 shown, the hybrid electromagnet is located between the hybrid electromagnet fixed sleeve 6 and the electrical pure iron 8; the hybrid electromagnet fixed sleeve 6 is fixedly connected to the motor output shaft 1.

[0039] The front end of the motor support frame 10 extends into the joint housing 7 , and the electrical pure iron 8 is sleeved on the portion of the motor support frame 10 extending into the joint housing 7 .

[0040] The joint also includes a spring sheet 5, which is also located in the joint housing 7. The spring sheet 5 is fixedly sleeved on the motor output shaft 1 through a spring sheet fixing sleeve 14, and the outer end of the spring sheet 5 extends into the anti-rotation groove 7-1 on the inner wall of the joint housing 7 (to position the outer end of the spring sheet 5).

[0041] The hybrid electromagnet includes a plastic bobbin 19, a copper coil 20, a permanent magnet 22 and an iron core 25; the iron core 25 is symmetrically arranged on both sides of the permanent magnet 22, the plastic bobbin 19 is sleeved on the iron core 25 and consolidated with the iron core 25, the copper coil 20 is sleeved on the plastic bobbin 19 and arranged coaxially with the plastic bobbin 19, the plastic bobbin 19, the copper coil 20, the permanent magnet 22 and the iron core 25 form a whole, and the permanent magnet 22 and the iron core 25 are connected to the hybrid electromagnet fixed sleeve 6.

[0042] Two fixed baffles 23 are located at the front and rear sides of the iron core 25 and the bottom of the permanent magnet 22 (the bottom is Figure 4 The lower part shown in the figure is fixed with the iron core 25 and the permanent magnet 22 by the hybrid electromagnet fastening bolts 21 and the hybrid electromagnet fastening nuts 24, and then the iron core 25 and the permanent magnet 22 are fixed on the hybrid electromagnet fixed sleeve 6 by the fixed baffle 23.

[0043] The spring leaves 5 are composed of two pieces, and the two spring leaves 5 are symmetrically arranged with the motor output shaft 1 as the symmetry axis. The outer ends of the two spring leaves 5 are embedded in the anti-rotation groove 7 - 1 on the inner wall of the joint housing 7 .

[0044] The front end of the joint housing 7 ( Figure 4 The upper end) is provided with a joint end cover 4;

[0045] Specifically, the present application sequentially arranges a joint end cover 4, a small tapered roller bearing 2, a spring sheet 5, a spring sheet fixing sleeve 14, a hybrid electromagnet fixing sleeve 6, a hybrid electromagnet, a joint housing 7, a motor support frame 10, electrical pure iron 8, a large tapered roller bearing 11, and an encoder 9. The joint end cover 4 is concentrically arranged with the motor output shaft 1 through the small tapered roller bearing 2, and the joint end cover 4 and the joint housing 7 are fixed by four joint end cover fastening bolts 2; the inner ring of the small tapered roller bearing 2 is concentrically arranged with the motor output shaft 1, and the outer ring of the small tapered roller bearing 2 cooperates with the joint end cover 4.

[0046] The hybrid electromagnet is concentrically fixed to the motor output shaft 1 through the hybrid electromagnet fixing sleeve 6. The hybrid electromagnet is divided into two groups, and the two groups of hybrid electromagnets are symmetrically arranged on both sides of the motor output shaft 1 at equal distances, that is, the motor output shaft 1 is taken as the symmetry axis.

[0047] The front end of the motor A is connected to the motor output shaft 1 through the motor reducer B) (such as Figure 1 As shown, the motor A and the motor reducer B are both located in the motor support frame 10 , and the end surface of the motor reducer B and the motor support frame 10 are fixed by three motor support frame fastening bolts 17 .

[0048] The inner ring of the large tapered roller bearing 11 is matched with the outer wall of the motor support frame 10 , and the outer ring of the large tapered roller bearing 11 is matched with the electrical pure iron 8 .

[0049] The bottom surface of the electrical pure iron 8 and the bottom surface of the joint housing 7 are fixed by four electrical pure iron fastening bolts 12; the bottom surface of the motor A cooperates with the encoder 9.

[0050] When in use, the front end of the motor output shaft 1 (i.e. Figure 1 The upper end of the motor A is used as the joint output end, the motor A rotates to drive the output shaft 1 to rotate, and the output shaft 1 drives the hybrid electromagnet fixed sleeve 6 to rotate. At this time, the copper coil 20 in the hybrid electromagnet is energized to generate magnetism, and because the electrical pure iron 8 is fixed and does not rotate, a torsion force is generated between the hybrid electromagnet and the electrical pure iron 8, and the motion or force is transmitted to the joint output end by the hybrid electromagnet. In addition, if it is provided with a spring sheet 5, at this time, the spring sheet 5 is driven by the rotation of the motor output shaft 1 to form an elastic deformation (the two spring sheets produce a deformation similar to an "S" shape, that is, the two spring sheets are deformed and form a deformation similar to an "S" shape). At this time, the motion or force is transmitted to the joint output end by the hybrid electromagnet and the spring sheet 5. Due to the nonlinear magnetic force of the hybrid electromagnet on the non-contact electrical pure iron 8 and the elastic deformation of the spring sheet 5, the joint stiffness can be nonlinearly changed. When the robot collides with the surrounding environment or the operator to make the joint output end twist, the protection functions such as buffering and vibration absorption can be generated by adjusting the joint stiffness of the hybrid electromagnet and the spring sheet 5.

[0051] By adjusting the magnitude and direction of the current in the copper coil 20, the magnetic flux in the magnetic circuit system can be increased or decreased, thereby adjusting the magnetic force of the hybrid electromagnet on the non-contact electrical pure iron 8, and further achieving a change in the joint stiffness.

[0052] Joint stiffness variation range: The stiffness of the hybrid electromagnet is K h By changing the current in the copper coil 20, the hybrid electromagnet adjusts the magnetic force of the non-contact electrical pure iron 8. The range of the hybrid electromagnet stiffness change is: 0≤K h ≤K 2 The joint stiffness generated by the spring sheet 5 is K 1 The change of the total stiffness K of the joint is determined by the spring sheet 5 and the hybrid electromagnet, so the change range of the total stiffness K is: K 1 ≤K≤K 1 +K 2 K represents the stiffness of the entire joint, K 1 is the spring stiffness, K h is the stiffness of the hybrid electromagnet. By adjusting the magnitude and direction of the current in the copper coil 20, the magnetic flux in the magnetic circuit system can be increased or decreased. When the reverse current is passed, the stiffness of the hybrid electromagnet K h The minimum value can reach 0, the stiffness K of the hybrid electromagnet when the forward current is passed h The maximum value can reach K 2 (K 2 Just mix the electromagnet stiffness K h Specifically, the stiffness K of the hybrid electromagnet when the forward current is passed is h The maximum value can reach K 2 ). So the stiffness of the whole joint is the stiffness of the spring sheet + the stiffness of the hybrid electromagnet: K 1 ≤K≤K 1 +K 2 .

[0053] The present invention is further described in detail below in conjunction with the accompanying drawings. This allows the present invention to fully understand how to use technical means to solve technical problems and achieve the technical process of the effect, and to implement it accordingly. It should be noted that as long as there is no conflict, the various embodiments of the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0054] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4Describe this embodiment, this embodiment includes: a motor, a small tapered roller bearing, a joint end cover fastening bolt assembly, a joint end cover, a spring sheet, a hybrid electromagnet fixed sleeve, a joint housing, electrical pure iron, an encoder, a motor support frame, a large tapered roller bearing, an electrical pure iron fastening bolt assembly, a spring sheet fastening nut, a spring sheet fixed sleeve, a hybrid electromagnet sleeve bolt assembly, a hybrid electromagnet sleeve nut assembly, a motor support frame fastening bolt assembly, a spring sheet fastening bolt, a plastic spool, a copper coil, a hybrid electromagnet fastening bolt, a permanent magnet, a fixed baffle, a hybrid electromagnet fastening nut, and an iron core.

[0055] The present invention stores and releases energy through the elastic deformation of a spring sheet. The two ends of the spring sheet are symmetrically embedded in the inner wall of the matching joint housing, and the spring sheet is fixed by a spring sheet fixing sleeve through a spring sheet fastening bolt and a spring sheet fastening nut. The spring sheet fixing sleeve is fixed in cooperation with the motor shaft. The meshing point between the spring sheet and the output shaft is the force application point of the load torque, and the length of the force arm remains unchanged. The spring sheet is driven to rotate by a motor, so that the spring sheet produces different degrees of deflection deformation, and accordingly, it plays a certain protective role when the joint is overloaded.

[0056] The hybrid electromagnets are symmetrically arranged at equal distances on both sides of the motor shaft. The hybrid electromagnets are composed of permanent magnets, iron cores, plastic bobbins, copper coils, fixed baffles, hybrid electromagnet fastening bolts, hybrid electromagnet fastening nuts, hybrid electromagnet fixed sleeves, hybrid electromagnet sleeve bolt assemblies, and hybrid electromagnet sleeve nut assemblies.

[0057] The iron core is symmetrically arranged on both sides of the permanent magnet, the plastic bobbin is fixed to the iron core, the copper coil is coaxially arranged with the plastic bobbin, and the front and rear support plates are fixed at the bottom of the iron core and the permanent magnet by hybrid electromagnet fastening bolts and hybrid electromagnet fastening nuts.

[0058] The electrical pure iron is fixed to the bottom surface of the joint housing by 4 electrical pure iron fastening bolts, and an air gap of 1mm is left between it and the hybrid electromagnet.

[0059] The magnetic flux in the joint magnetic circuit system is determined by the permanent magnet and the current in the excitation coil. Therefore, by changing the magnitude and direction of the current in the excitation coil, the magnetic flux in the magnetic circuit system can be increased or decreased, that is, the joint stiffness can be increased or decreased, and the change in joint stiffness is nonlinear.

[0060] The present invention is a permanent magnet variable stiffness flexible robot joint with a simple motion form, simple manufacturing and simple operation. The hybrid electromagnet is a combination of a permanent magnet and an excitation coil, which combines the advantages of a permanent magnet and an electromagnet. The permanent magnet can maintain the magnetic force and stiffness in an unpowered state (due to the magnetic force of the permanent magnet 22 itself, even if the hybrid electromagnet is not powered, there is still a certain magnetic force, and the joint has a certain stiffness), and has energy-saving characteristics. The joint stiffness adjustment part adopts the combined action of the hybrid electromagnet and the spring sheet. Since the hybrid electromagnet is used to adjust the joint stiffness, it has the advantages of fast stiffness adjustment response speed, no delay, no lag, etc.

Claims

1. A variable stiffness joint for a flexible robot based on a hybrid electromagnet, characterized in that: It comprises a motor A, a hybrid electromagnet fixing sleeve (6), a hybrid electromagnet, a joint housing (7), electrical pure iron (8) and a motor support frame (10); the hybrid electromagnet fixing sleeve (6), the hybrid electromagnet and the electrical pure iron (8) are located in the joint housing (7); The motor support frame (10) is sleeved outside the motor A, the motor output shaft (1) passes through the front end of the motor support frame (10), the hybrid electromagnet is installed at the rear end of the hybrid electromagnet fixed shaft sleeve (6), the hybrid electromagnet is located between the hybrid electromagnet fixed shaft sleeve (6) and the electrical pure iron (8), and the hybrid electromagnet fixed shaft sleeve (6) is fixedly connected to the motor output shaft (1); The front end of the motor support frame (10) extends into the joint housing (7), and the electrical pure iron (8) is sleeved on the portion of the motor support frame (10) extending into the joint housing (7); The joint further comprises a spring sheet (5), which is also located in the joint housing (7). The spring sheet (5) is fixedly sleeved on the motor output shaft (1) via a spring sheet fixing sleeve (14), and the outer end of the spring sheet (5) extends into a rotation-stop groove (7-1) on the inner wall of the joint housing (7). The hybrid electromagnet comprises a plastic bobbin (19), a copper coil (20), a permanent magnet (22) and an iron core (25); the iron core (25) is symmetrically arranged on both sides of the permanent magnet (22); the plastic bobbin (19) is sleeved on the iron core (25) and is fixed to the iron core (25); the copper coil (20) is sleeved on the plastic bobbin (19) and is coaxially arranged with the plastic bobbin (19); the plastic bobbin (19), the copper coil (20), the permanent magnet (22) and the iron core (25) form a whole; the permanent magnet (22) and the iron core (25) are connected to a hybrid electromagnet fixed sleeve (6); A joint end cover (4) is provided at the front end of the joint housing (7); the joint end cover (4) and the motor output shaft (1) are arranged concentrically via a small tapered roller bearing (2); and the joint end cover (4) and the joint housing (7) are fixed.

2. According to claim 1, a variable stiffness joint for a flexible robot based on a hybrid electromagnet is characterized in that: Two fixed baffles (23) are fixed to the iron core (25) and the permanent magnet (22) at the front and rear sides of the bottom of the iron core (25) and the permanent magnet (22), and the iron core (25) and the permanent magnet (22) are fixed to the hybrid electromagnet fixed shaft sleeve (6) by the fixed baffles (23).

3. The variable stiffness joint for a flexible robot based on a hybrid electromagnet according to claim 1, characterized in that: The spring leaves (5) are two pieces, and the two spring leaves (5) are symmetrically arranged with the motor output shaft (1) as a symmetry axis. The outer ends of the two spring leaves (5) are embedded in the anti-rotation groove (7-1) on the inner wall of the joint housing (7).

4. The variable stiffness joint for a flexible robot based on a hybrid electromagnet according to claim 1, characterized in that: The hybrid electromagnet is coaxially fixed to the motor output shaft (1) via a hybrid electromagnet fixing sleeve (6). The hybrid electromagnet is divided into two groups, and the two groups of hybrid electromagnets are symmetrically arranged at equal distances on both sides of the motor output shaft (1).

5. The variable stiffness joint for a flexible robot based on a hybrid electromagnet according to claim 1, characterized in that: The end surface of the motor reducer (B) and the motor support frame (10) are fixed by three motor support frame fastening bolts (17).

6. The variable stiffness joint for a flexible robot based on a hybrid electromagnet according to claim 1, characterized in that: The inner ring of the large tapered roller bearing (11) is matched with the outer wall of the motor support frame (10), and the outer ring of the large tapered roller bearing (11) is matched with the electrical pure iron (8).

7. The variable stiffness joint for a flexible robot based on a hybrid electromagnet according to claim 1, characterized in that: The bottom surface of the electrical pure iron (8) is fixed to the bottom surface of the joint housing (7); the bottom surface of the motor (A) is matched with the encoder (9).

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