An adjustable stiffness robot joint based on series elastic actuator

Abstract

The application relates to the technical field of robot motion, in particular to a robot joint with adjustable rigidity based on a series elastic driver, which comprises a motor with an encoder, a harmonic reducer, a flange, a first connecting plate, a second connecting plate, a bearing, a series elastic body, an end cover and a magnetic encoder, and the harmonic reducer comprises a wave generator, a flexible gear and a rigid gear; the motor with the encoder is connected with the wave generator, the first connecting plate is fixedly connected with the flexible gear, the flange and the second connecting plate are sleeved on the rigid gear, and the second connecting plate covers the end surface of the flange; one side of the series elastic body is connected with the second connecting plate, and the other side is fixedly connected with the end cover. The joint solves the problems that the existing robot joint structure is not compact, it is difficult to output accurate torque, and the transmission precision is low, and the application is used for robots.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robot motion, in particular to a robot joint with adjustable stiffness based on a series elastic actuator. BACKGROUND

[0002] A robot joint is one of the key components of a robot, responsible for transmitting power and achieving motion. With the rapid development of robot technology, especially in the fields of service robots, exoskeleton robots, industrial robots, etc., the design and performance of robot joints have a direct impact on the motion ability and flexibility of robots.

[0003] The traditional drive used in robot joints is a rigid drive, but rigid drive joints may cause a series of safety problems due to insufficient compliance and difficulty in current control in torque control, such as damage to their own structure and function due to lack of buffering when facing excessive impact. Flexible joints have compliance due to the design of elastic elements, can resist impact and perform force sensing, etc., but have problems such as lack of reliability, narrow passband, slow response, and inaccuracy. SUMMARY

[0004] The present application provides a robot joint with adjustable stiffness based on a series elastic actuator, which realizes adjustable stiffness by introducing a specially designed series elastic body, avoids the basic performance limitations of conventional series elastic bodies, and solves the problems of existing robot joint structures that are not compact, difficult to output accurate torque, and low transmission precision.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0006] A robot joint with adjustable stiffness based on a series elastic actuator, comprising a motor with an encoder, a harmonic reducer, a flange, a first connecting plate, a second connecting plate, a bearing, a series elastic body, an end cover, a magnetic encoder, a joint fixed end, and a joint moving end; the harmonic reducer comprises a wave generator, a flexible gear, and a rigid gear, the wave generator is assembled in the inner circle of the flexible gear, the rigid gear is engaged with the flexible gear, and the harmonic reducer uses a connection mode of flexible gear end fixed and rigid gear end output; the output end of the motor with an encoder is connected with the wave generator, and the first connecting plate is fixedly connected with the flexible gear; the flange and the second connecting plate are sleeved on the rigid gear and fixedly connected with the rigid gear, and the second connecting plate covers the end face of the flange; one side of the series elastic body is connected with the second connecting plate, and the other side is fixedly connected with the end cover, and the end cover is provided with a magnetic encoder at one end; the lower part of the joint fixed end is fixedly connected with the first connecting plate, and the joint moving end is fixedly connected with the lower end of the end cover.

[0007] Further, the series elastic body comprises an outer ring output structure, an inner ring rotating structure and elastic elements, the inner ring rotating structure is connected with the inner ring of the bearing, the inner side of the outer ring output structure is connected with the outer ring of the bearing, and the right end of the outer ring output structure is fixedly connected with the end cover.

[0008] Further, the outer ring output structure comprises an output shell, four spring fixing blocks and screws, the spring fixing blocks are fixedly connected with the corner portions of the output shell through the screws, and the output shell is connected with the outer ring of the bearing.

[0009] Further, the elastic elements of the series elastic body comprise four groups of springs and four groups of spring pins, one end of the spring pin is connected with the inner ring rotating structure, the other end is connected with the spring fixing block, and the spring is sleeved on the spring pin.

[0010] Further, the inner ring rotating structure comprises an inner rotating shaft, four electromagnetic assemblies, the outer side of the inner rotating shaft is connected with the inner ring of the bearing, one end of the inner rotating shaft is connected with the second connecting plate, the inner rotating shaft rotates synchronously with the ratchet wheel and the second connecting plate; the electromagnetic assembly comprises an electromagnetic rod and an electromagnetic rod sleeve, the electromagnetic rod is arranged in the circumferential direction of the inner rotating shaft, the electromagnetic rod sleeve is in contact with the spring, and the electromagnetic rod sleeve slides on the spring pin; the energization of each electromagnetic rod is independently controlled by a control end, and when the electromagnetic rod is energized, the electromagnetic rod pops into the electromagnetic rod sleeve.

[0011] Further, each group of springs comprises two springs, which are denoted as a first spring and a second spring, the electromagnetic rod sleeve is located between the first spring and the second spring, and the first spring and the second spring are both abutted between the corresponding spring fixing block and the electromagnetic rod sleeve; each group of spring pins also comprises two spring pins, which are denoted as a first spring pin and a second spring pin, and the first spring pin and the second spring pin correspond to the first spring and the second spring respectively.

[0012] Further, the electromagnetic rod and the electromagnetic rod sleeve of the series elastic body adopt a triangular structure for insertion, and the electromagnetic rod can be adaptively popped into the electromagnetic rod sleeve.

[0013] Further, when a group of electromagnetic rods are energized and popped into the electromagnetic rod sleeve and are elongated to the middle of the spring, only one group of springs participates in the movement, and the series elastic body is in a low-rigidity mode; when two groups of electromagnetic rods are energized and elongated to the middle of the spring, two groups of springs work in series, and the series elastic body is in a medium-low-rigidity mode; when three groups of electromagnetic rods are energized and elongated to the middle of the spring, three groups of springs work in series, and the series elastic body is in a medium-rigidity mode; when four groups of electromagnetic rods are all energized and elongated to the middle of the spring, four groups of springs work in series, and the series elastic body is in a high-rigidity mode; the electromagnetic rods will pop back at the moment of power-off, the four groups of electromagnetic rods are disconnected with the electromagnetic rod sleeve, and thus the inner rotating shaft of the series elastic body is separated from the outer ring output shell.

[0014] Further, the motor with the encoder is a hollow frameless torque motor, the harmonic reducer is a hollow harmonic reducer, and the magnetic encoder is a hollow encoder.

[0015] Further, an inertial measurement unit is installed on the joint movement end.

[0016] Further, the joint movement end is of a telescopic structure. Further, the electromagnetic rods rebound at the moment of power-off, the four groups of electromagnetic rods are disconnected from the electromagnetic rod sleeve, and the internal rotating shaft of the series elastic body is separated from the outer ring output shell.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] First, the present application is suitable for a flexible joint applied in the field of robots. The power of the frameless torque motor is converted into the rotary power output of the joint through the harmonic reducer. The application of the frameless torque motor and the harmonic reducer makes the joint structure compact and the motion precision high.

[0019] Second, the present application adopts a series elastic body designed by itself. The series elastic body adopts a split structure, is simple to assemble, and makes the joint have good impact resistance. The elastic body has four groups of symmetrical compression springs in total. The elastic body can obtain four kinds of stiffness through the elongation of different numbers of electromagnetic rods into the middle of the springs, so as to meet the demand of the stiffness of the joint of the robot under different working conditions. The electromagnetic rods can rebound at the moment of power-off, so that the rotating shaft of the elastic body is separated from the outer ring output shell, that is, the driving device is separated from the execution end. Therefore, the joint can effectively prevent accidental injury caused by instantaneous large impact during motion.

[0020] Third, the joint has two encoders. One is the self-encoder of the motor, which is used for measuring the rotation angle of the output end of the motor. The other is the magnetic encoder placed on the end cover, which is used for measuring the motion angle of the actuator. The angle difference between the two encoders represents the flexible deformation. The product of the angle difference and the stiffness value of the elastic body can obtain the accurate output torque of the joint, so as to ensure the good motion control characteristics of the joint.

[0021] Fourth, the frameless motor, the harmonic reducer, and the magnetic encoder are all hollow designs. The cables can be routed from the center of the joint, which can protect the cables and will not affect the rotation of the joint.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] First, the present application is suitable for a flexible joint applied in the field of robots. The power of the frameless torque motor is converted into the rotary power output of the joint through the harmonic reducer. The application of the frameless torque motor and the harmonic reducer makes the joint structure compact and the motion precision high.

[0024] Second, the application adopts a self-designed series elastic body, the series elastic body adopts a split structure, is simple to assemble, and makes the joint have good impact resistance; the elastic body has four groups of symmetrically distributed compression springs, different numbers of electromagnetic rods are elongated to the middle of the springs, the elastic body can obtain four kinds of stiffness in total, so as to meet the demand of the joint of the robot in different working conditions on stiffness. The electromagnetic rods can rebound at the moment of power-off, so that the rotating shaft of the elastic body is separated from the outer ring output shell, that is, the driving device is separated from the actuator, therefore, the joint can effectively prevent accidental injury caused by instantaneous large impact during movement.

[0025] Third, the joint has two encoders, one is a motor self-provided encoder, which is used for measuring the rotating angle of the motor output end, and the other is a magnetic encoder arranged on the end cover, which is used for measuring the movement angle of the actuator, the angle difference of the two encoders is used to represent the flexible deformation, and the product of the angle difference and the stiffness value of the elastic body can obtain the accurate output torque of the joint, so as to ensure the good movement control characteristics of the joint.

[0026] Fourth, the frameless motor, the harmonic reducer and the magnetic encoder are all hollow designs, can be wired from the center of the joint, play the role of protecting the cable, and at the same time will not affect the rotation of the joint. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a whole structure perspective view of the adjustable stiffness robot joint based on the series elastic driver of the application;

[0028] Figure 2 It is another whole structure perspective view of the adjustable stiffness robot joint based on the series elastic driver of the application;

[0029] Figure 3 It is a main sectional view of the whole structure of the application;

[0030] Figure 4 It is a perspective view of the series elastic body of the application;

[0031] Figure 5 It is a front view of the series elastic body of the application;

[0032] Figure 6 It is an explosion view of the application;

[0033] Figure 7 It is a multi-stiffness schematic view of the series elastic body of the application;

[0034] Figure 8 It is a spring self-adapting flowchart of the application.

[0035] In the figure, 1, motor with encoder; 2, harmonic reducer; 2-1, wave generator; 2-2, flexspline; 2-3, rigid wheel; 3, flange plate; 4, first connecting plate; 5, second connecting plate; 6, bearing; 7, series elastic body; 7-1, outer ring output structure; 7-2, inner ring rotating structure; 7-3, elastic element; 8, end cover; 9, magnetic encoder; 10, joint fixed end; 11, joint moving end; 12, inertial measurement unit; 13, adjusting bolt; 14, adjusting nut; 15, output shell; 16, spring fixing block; 17, screw; 18, spring; 18-1, first spring; 18-2, second spring; 19, spring pin; 20, inner rotating shaft; 21, electromagnetic assembly; 21-1, electromagnetic rod sleeve; 21-2, electromagnetic rod. DETAILED DESCRIPTION

[0036] The application will be further described below in connection with specific embodiments, which are intended to explain but not to limit the application.

[0037] In connection with Figures 1-6 In this embodiment, the adjustable stiffness robot joint based on series elastic driver includes a motor with encoder 1, a harmonic reducer 2, a flange plate 3, a first connecting plate 4, a second connecting plate 5, a bearing 6, a series elastic body 7, an end cover 8, a magnetic encoder 9, a joint fixed end 10, and a joint moving end 11. The harmonic reducer 2 includes a wave generator 2-1, a flexspline 2-2, and a rigid wheel 2-3. The wave generator 2-1 is assembled in the inner circle of the flexspline 2-2, and the rigid wheel 2-3 is engaged with the flexspline 2-2. The harmonic reducer uses a connection mode of fixed flexspline end and output rigid wheel end. The output end of the motor with encoder 1 is connected with the wave generator 2-1, and the first connecting plate 4 is fixedly connected with the flexspline 2-2. The flange plate 3 and the second connecting plate 5 are sleeved on the rigid wheel 2-3 and fixedly connected with the rigid wheel 2-3. The second connecting plate 5 covers the end face of the flange plate 3. One side of the series elastic body 7 is connected with the second connecting plate 5, and the other side is fixedly connected with the end cover 8. One end of the end cover 8 is provided with the magnetic encoder 12.

[0038] Referring to Figure 4 and Figure 6 As shown in the figure, the series elastic body 7 includes an outer ring output structure 7-1, an inner ring rotating structure 7-2, and an elastic element 7-3. The inner ring rotating structure 7-2 is connected with the inner ring of the bearing 6, the inner side of the outer ring output structure 7-1 is connected with the outer ring of the bearing 6, and the right end of the outer ring output structure 7-1 is fixedly connected with the end cover 8. In this embodiment, the bearing 6 is a deep groove ball bearing 6.

[0039] Referring to Figure 5As shown, the outer ring output structure 7-1 includes an output shell 15, four spring fixing blocks 16 and screws 17, the spring fixing blocks 16 are fixedly connected with the corners of the output shell 15 through the screws 17, and the output shell 15 is connected with the outer ring of the bearing 6.

[0040] Referring to Figure 5 As shown, the elastic element 7-3 of the series elastic body 7 includes four groups of springs 18 and four groups of spring pins 19, one end of the spring pin 19 is connected with the inner ring rotating structure 7-2, the other end is connected with the spring fixing block 16, and the spring 18 is sleeved on the spring pin 19.

[0041] Referring to Figure 4 , 5 , as shown in 6, the inner ring rotating structure 7-1 includes an inner rotating shaft 20 and four electromagnetic assemblies 21, the outer side of the inner rotating shaft 20 is connected with the inner ring of the bearing 6, one end of the inner rotating shaft 20 is connected with the second connecting plate 5, and the inner rotating shaft 20 rotates synchronously with the rigid wheel 2-2 and the second connecting plate 5; the electromagnetic assembly 21 includes an electromagnetic rod 21-2 and an electromagnetic rod sleeve 21-1, the electromagnetic rod 21-2 is arranged circumferentially along the inner rotating shaft 20, the electromagnetic rod sleeve 21-1 is connected with the spring 18, and the electromagnetic rod 21-2 is sleeved and slides on the spring pin 19; the energization of each electromagnetic rod 21-2 is independently controlled by a control end, and the electromagnetic rod 21-2 is ejected into the electromagnetic rod sleeve 21-1 after being energized, and the assembly pushes the spring to move during work.

[0042] Referring to Figure 5 As shown, each group of springs 18 includes two springs, denoted as a first spring 18-1 and a second spring 18-2, and the electromagnetic rod sleeve 21-1 is located between the first spring 18-1 and the second spring 18-2, and the first spring 18-1 and the second spring 18-2 are both abutted between the corresponding spring fixing block 16 and the electromagnetic rod sleeve 21-1. Each group of spring pins 19 also includes two spring pins, denoted as a first spring pin and a second spring pin, and the first spring pin and the second spring pin correspond to the first spring 18-1 and the second spring 18-2 respectively.

[0043] In combination Figure 8 It is explained that the electromagnetic rod 21-2 and the electromagnetic rod sleeve 21-1 of the series elastic body 7 in the embodiment adopt a triangular structure for insertion, so that the electromagnetic rod sleeve 21-1 can adaptively eject the electromagnetic rod 21-2.

[0044] In combination Figure 7 , 8It is explained that in the embodiment, when the series elastic body 7 is energized, the elastic rod 21-2 of one group of the electromagnetic rod 21-2 is inserted into the electromagnetic rod sleeve 21-1, and when the elastic rod 21-2 is elongated to the middle of the spring 18, only one group of the spring 18 participates in the movement, and the series elastic body 7 is in a low stiffness mode; when the elastic rod 21-2 of two groups of the electromagnetic rod 21-2 is elongated to the middle of the spring 18, two groups of the spring 18 work in series, and the series elastic body 7 is in a medium-low stiffness mode; when the elastic rod 21-2 of three groups of the electromagnetic rod 21-2 is elongated to the middle of the spring 18, three groups of the spring 18 work in series, and the series elastic body 7 is in a medium stiffness mode; when the elastic rod 21-2 of four groups of the electromagnetic rod 21-2 is elongated to the middle of the spring 18, four groups of the spring 18 work in series, and the series elastic body 7 is in a high stiffness mode; the electromagnetic rod 21-2 is rebounded at the moment of power-off, the four groups of the electromagnetic rod 21-2 are disconnected with the spring 18, and the internal rotating shaft 20 of the series elastic body 7 is separated from the outer ring output shell 15.

[0045] In combination Figure 3 It is explained that in the embodiment, the harmonic reducer 2 has the advantages of high precision, large transmission ratio and compact structure, the motor 1 with an encoder is a hollow frameless torque motor, the harmonic reducer 2 is a hollow harmonic reducer, and the magnetic encoder 12 is a hollow encoder. In this way, the joint wiring is stable, the cable is protected, and the joint is safe and reliable.

[0046] In combination Figure 1 , 3 It is explained that in the embodiment, the lower part of the joint fixed end 10 is fixedly connected with the first connecting plate 4, and the joint moving end 11 is fixedly connected with the lower end of the end cover 8; the inertia measurement unit 12 is installed on the joint moving end 11.

[0047] In combination Figure 6 It is explained that the joint moving end 11 is a telescopic structure, and in the embodiment, the joint moving end 11 is provided with a sliding groove and three bolt hole positions; by installing the adjusting bolt 13 and the adjusting nut 14 in different hole positions, the length of the joint moving end 11 can be adjusted.

[0048] The working principle of the adjustable stiffness robot joint based on the series elastic driver is as follows:

[0049] The motor 1 with an encoder transmits the torque to the harmonic reducer 2, the torque is transmitted to the second connecting plate 5 through the amplification of the harmonic reducer 2; the second connecting plate 5 rotates synchronously with the internal rotating shaft 20 of the series elastic body 7, the output shell 15 of the series elastic body 7 is connected between the internal rotating shaft 20 and the inner and outer rings of the bearing 6, the spring 18 is installed on the output shell 15, the internal rotating shaft 20 and the output shell 15 produce relative displacement to compress the spring 18, and the spring 18 drives the output shell 15 to move.

[0050] Suppose n One group of the spring 18 participates in the movement, and the stiffness of one group of the spring 18 is kWhen a group of electromagnetic rods 21-2 is energized to pop into the electromagnetic rod sleeve 21-1 and extend to the middle of the spring 18, only one group of springs 18 participates in the movement, the elastomer is in a low stiffness mode, and the stiffness is k; when two groups of electromagnetic rods 21-2 extend to the middle of the spring 18, two groups of springs 18 work in series, the elastomer is in a medium-low stiffness mode, and the stiffness is 2x k ; when three groups of electromagnetic rods 21-2 extend to the middle of the spring 18, the elastomer is in a medium stiffness mode, and the stiffness is 3x k ; when four groups of electromagnetic rods 21-2 extend to the middle of the spring 18, the elastomer is in a high stiffness mode, and the stiffness is 4x k .

[0051] The rotation angle difference between the inner and outer rings of the series elastic body 7 can be measured by using the encoder of the motor 1 and the magnetic encoder 9 installed on the side end of the end cover 8 θ , so that the joint output torque can be accurately measured M : M = n x k x θ , position control or speed control of the joint is performed.

[0052] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "rear", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0053] In addition, unless otherwise explicitly specified and limited, if the terms "mounting", "connection" appear, they should be broadly understood, for example, they can be fixedly connected, or detachably connected, or integrally connected; they can be mechanically connected, or electrically connected; they can be directly connected, or indirectly connected through an intermediate medium, and they can be connected inside two elements. The specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0054] The above description is only the preferred embodiment of the present application, and does not limit the technical solutions of the present application in any way. Those skilled in the art should understand that without departing from the spirit and principles of the present application, the technical solutions can also be modified and replaced in several simple ways, and these modifications and replacements also belong to the protection scope covered by the claims.

Claims

1. An adjustable stiffness robot joint based on a series elastic actuator, characterized in that, The system includes a motor (1) with an encoder, a harmonic reducer (2), a flange (3), a first connecting plate (4), a second connecting plate (5), a bearing (6), a series elastomer (7), an end cap (8), a magnetic encoder (9), a joint fixed end (10), and a joint moving end (11); the harmonic reducer includes a waveform generator (2-1), a flexible wheel (2-2), and a rigid wheel (2-3), the waveform generator (2-1) being mounted in the inner circle of the flexible wheel (2-2), and the rigid wheel (2-3) meshing with the flexible wheel (2-2); the output end of the motor (1) with the encoder is connected to... A waveform generator (2-1) is connected, and a first connecting plate (4) is fixedly connected to a flexible wheel (2-2); a flange (3) and a second connecting plate (5) are fitted onto a rigid wheel (2-3) and fixedly connected to the rigid wheel (2-3); the second connecting plate (5) covers the end face of the flange (3); one side of the series elastic body is connected to the second connecting plate, and the other side is fixedly connected to the end cover; a magnetic encoder (9) is installed at one end of the end cover (8); the lower part of the joint fixed end (10) is fixedly connected to the first connecting plate (4), and the joint moving end (11) is fixedly connected to the lower end of the end cover (8); The series elastomer (7) includes an outer ring output structure (7-1), an inner ring rotation structure (7-2), and an elastic element (7-3). The inner ring rotation structure (7-2) is connected to the inner ring of the bearing (6), the inner side of the outer ring output structure (7-1) is connected to the outer ring of the bearing (6), and the right end of the outer ring output structure (7-1) is fixedly connected to the end cap (8). The outer ring output structure (7-1) of the series elastomer (7) includes an output housing (15), four spring fixing blocks (16) and screws (17). The spring fixing blocks (16) are fixedly connected to the corners of the output housing (15) by screws (17). The output housing (15) is connected to the outer ring of the bearing (6). The elastic element (7-3) of the series elastic body (7) includes four sets of springs (18) and four sets of spring pins (19). One end of the spring pin (19) is connected to the inner ring rotating structure (7-2), and the other end is connected to the spring fixing block (16). The spring (18) is sleeved on the spring pin (19). The inner ring rotation structure (7-2) of the series elastic body (7) includes an inner rotating shaft (20) and four electromagnetic assemblies (21). The outer side of the inner rotating shaft (20) is connected to the inner ring of the bearing (6). One end of the inner rotating shaft (20) is fixedly connected to the second connecting plate (5). The inner rotating shaft (20) rotates synchronously with the rigid wheel (2-3) and the second connecting plate (5). The electromagnetic assembly includes an electromagnetic rod (21-2) and an electromagnetic rod sleeve (21-1). The electromagnetic rod (21-2) is arranged circumferentially along the inner rotating shaft (20). The electromagnetic rod sleeve (21-1) is in contact with the spring (18). The electromagnetic rod sleeve (21-1) slides on the spring pin (19). The energization of each electromagnetic rod (21-2) is independently controlled by the control terminal. When energized, the electromagnetic rod (21-2) pops out into the electromagnetic rod sleeve (21-1). Each set of springs (18) includes two springs, referred to as the first spring (18-1) and the second spring (18-2). The electromagnetic rod sleeve (21-1) is located between the first spring (18-1) and the second spring (18-2). The first spring (18-1) and the second spring (18-2) abut against the corresponding spring fixing block (16) and the electromagnetic rod sleeve (21-1). Each set of spring pins (19) also includes two spring pins, referred to as the first spring pin and the second spring pin. The first spring pin and the second spring pin correspond to the first spring (18-1) and the second spring (18-2) respectively.

2. The adjustable stiffness robot joint based on a series elastic actuator according to claim 1, characterized in that: The electromagnetic rod (21-2) and electromagnetic rod sleeve (21-1) of the series elastic body (7) are connected by a triangular structure, and the electromagnetic rod (21-2) can adaptively spring into the electromagnetic rod sleeve (21-1).

3. The adjustable stiffness robot joint based on a series elastic actuator according to claim 1, characterized in that: The motor (1) with encoder is a hollow frameless torque motor, the harmonic reducer (2) is a hollow harmonic reducer, and the magnetic encoder (9) is a hollow encoder.

4. The adjustable stiffness robot joint based on a series elastic actuator according to claim 1, characterized in that: An inertial measurement unit (12) is installed on the joint motion end (11).

5. An adjustable stiffness robot joint based on a series elastic actuator according to claim 1, characterized in that: The joint movement end (11) is a telescopic structure.

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