Flexible joints and flexible mechanisms

Abstract

The present invention discloses a flexible mechanism, including a track assembly and a flexible assembly; the track assembly includes a first track and a second track, a first slider slidably matched with the first track is provided in the first track, and a second slider slidably matched with the second track is provided in the second track; the flexible assembly includes a traction rod rotating around a fixed axis, the second slider slidably matched with the traction rod, and a spring is provided between the first slider and the second slider to connect; when the position of the first slider in the first track remains stationary, the angle between the traction rod and the axis of the spring remains unchanged during the movement of the second slider along the second track; and: the angle between the traction rod and the axis of the spring changes as the first slider slides along the first track. The present invention also discloses a flexible joint. The flexible joint and flexible mechanism of the present invention can not only make the output stiffness of the joint adjustable, but also keep the stiffness unchanged during the rotation of the joint, so as to output the torque linearly.

Description

Technical Field

[0001] The invention belongs to the technical field of robots, and specifically relates to a flexible joint and a flexible mechanism. Background Art

[0002] With the continuous and rapid development of science and technology such as computer technology, electronic component technology and motor technology, robotics technology has also been rapidly improved and has been widely used in various production and life scenarios. Due to the excellent performance of legged robots, they have become a hot topic of research.

[0003] The stability and efficiency of legged robot movement not only depends on the complex robot control system, but also on its own mechanical structure. The legs of legged robots are the core components for realizing robot movement. The physical characteristics of the leg structure determine the robot's movement ability. Among them, the appropriate leg stiffness is of great significance to improving the stability of legged robots under high-speed movement and reducing the impact of the foot end. At different movement speeds and different ground environments, the movement stability and efficiency of legged robots have different requirements for leg stiffness. Therefore, it is necessary to make the leg stiffness actively adjustable according to different movement requirements, that is, the leg joints are required to actively adjust the joint output stiffness as needed. However, the stiffness of most variable stiffness flexible joints currently changes passively during joint rotation, that is, the output of joint torque is not a linear output, which brings difficulties to the establishment of robot motion control functions. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a flexible joint and a flexible mechanism, which can not only make the output stiffness of the joint adjustable, but also keep the stiffness unchanged during the rotation of the joint, so as to achieve linear torque output.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention firstly proposes a flexible mechanism, comprising a track component and a flexible component;

[0007] The track assembly comprises a first track and a second track, wherein a first slider is provided in the first track for sliding cooperation therewith, and a second slider is provided in the second track for sliding cooperation therewith;

[0008] The flexible component includes a traction rod rotating around a fixed axis, the second slider is slidably matched with the traction rod, and a spring is provided between the first slider and the second slider;

[0009] When the first slider remains stationary in the first track, the angle between the traction rod and the axis of the spring remains unchanged during the movement of the second slider along the second track; and:

[0010] The angle between the traction rod and the axis of the spring changes as the first sliding block slides along the first track.

[0011] Furthermore, the first track is a circular track or a straight track.

[0012] The present invention further proposes a flexible device, comprising a curved groove disk and a central shaft that rotates with the curved groove disk, at least two flexible mechanisms as claimed in claim 1 or 2 are evenly distributed in an annular pattern on the curved groove disk, the first track and the second track are arranged on the curved groove disk, the fixed shaft is coaxial with the central shaft, and the traction rod rotates synchronously with the central shaft;

[0013] It also includes a stiffness adjustment mechanism for driving the first slider to slide along the first track to change the angle between the traction rod and the axis of the spring.

[0014] Furthermore, the stiffness adjustment mechanism includes a stiffness adjustment disk rotatably matched with the central axis and a stiffness adjustment driving mechanism for driving the stiffness adjustment disk to rotate; the stiffness adjustment disk is provided with adjustment tracks corresponding to the first sliders one by one, and in the viewing direction along the axis of the central axis, the adjustment tracks intersect with the corresponding first tracks; the first slider slidably matches with the adjustment tracks.

[0015] Furthermore, the stiffness adjustment driving mechanism comprises an adjustment motor installed on the curved groove disk, and a gear transmission mechanism for driving the stiffness adjustment disk to rotate around the central axis is provided between the output shaft of the adjustment motor and the stiffness adjustment disk.

[0016] Furthermore, the gear transmission mechanism includes a driving gear arranged on the output shaft of the adjusting motor and a driven gear arranged on the outer peripheral wall of the stiffness adjusting disk and meshing with the driving gear.

[0017] Furthermore, the curved groove disk is provided with a center sleeve that is rotatably fitted on the center axis, the stiffness adjustment disk is rotatably fitted on the center sleeve, and the center sleeve is provided with a limit disk for preventing the stiffness adjustment disk from moving along the axial direction of the center axis, and the stiffness adjustment disk is located between the limit disk and the curved groove disk.

[0018] Furthermore, a grating encoder is installed on the central sleeve, and a grating encoder disk which rotates synchronously with the central shaft is provided on the central shaft.

[0019] Further, the flexible component is located between the curved groove plate and the stiffness adjustment plate; or, a protective plate is provided on the side of the curved groove plate facing away from the stiffness adjustment plate, and the flexible component is located between the curved groove plate and the protective plate.

[0020] Furthermore, a first auxiliary track and a second auxiliary track are provided on the protection plate, the first auxiliary track is arranged in a one-to-one correspondence with the first track, and the second auxiliary track is arranged in a one-to-one correspondence with the second track; in the viewing direction along the axis of the central axis, the center line of the first auxiliary track coincides with the center line of the corresponding first track, and the center line of the second auxiliary track coincides with the center line of the second track.

[0021] The beneficial effects of the present invention are:

[0022] The flexible mechanism of the present invention is configured such that a traction rod is arranged to rotate around a fixed axis, and the traction rod is slidably matched with a second slider, and a spring with variable length is arranged between the first slider and the second slider; by adapting the curved shapes of the first track and the second track, when the position of the first slider in the first track is kept stationary, the second slider moves along the second track, and the traction rod rotates around the fixed axis, and the angle between the traction rod and the axis of the spring remains unchanged, that is, during the rotation of the fixed axis, the stiffness output by the flexible mechanism can be kept unchanged, so as to achieve the technical purpose of linear output of torque; in addition, by adjusting the position of the first slider in the first track, the angle between the traction rod and the axis of the spring can be changed, so that the stiffness output by the flexible mechanism can be changed, and the output stiffness of the flexible mechanism can be adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0024] Figure 1 It is the principle diagram of variable transmission ratio based on variable slope;

[0025] Figure 2 This is a schematic diagram of the structure of the flexible mechanism embodiment 1 of the present invention;

[0026] Figure 3 This is the principle diagram of the rotary variable slope;

[0027] Figure 4 This is a schematic diagram of the structure of a quadruped robot;

[0028] Figure 5 is a graph of the centerline of the fitted second track;

[0029] Figure 6 It is a curve diagram of the joint output torque at different rotation angles;

[0030] Figure 7 It is a schematic structural diagram of an embodiment of a flexible joint of the present invention;

[0031] Figure 8 for Figure 7 AA section view;

[0032] Fig. 9 for Figure 7 Stereoscopic image of

[0033] Fig.10 It is a schematic diagram of the assembly structure of the curved groove plate, the stiffness adjustment plate and the protection plate;

[0034] Fig.11 of Fig.10 Right view

[0035] Fig.12 of Fig.10 Rear view of

[0036] Fig.13 It is a schematic diagram of the assembly structure between the curved slot plate and the flexible component;

[0037] Fig.14 for Fig.13 Front axonometric view of

[0038] Fig.15 for Fig.13 Rear axonometric drawing

[0039] Fig.16 This is the joint stiffness control curve.

[0040] Description of reference numerals:

[0041] 11-first track; 12-first slider; 13-second track; 14-second slider; 15-traction rod; 16-spring;

[0042] 21-curve groove disk; 22-center axis; 23-rigidity adjustment disk; 24-adjustment track; 25-adjustment motor; 26-driving gear; 27-passive gear; 28-center sleeve; 30-grating encoder; 31-grating encoder disk; 32-protection disk; 33-first auxiliary track; 34-second auxiliary track; 35-cylinder body; 36-cylinder cover; 37-first through hole; 38-second through hole. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0044] Example 1

[0045] like Figure 1 As shown, the stiffness of the linear spring is K S, the angle between the inclined plane and the horizontal plane is θ. One end of the linear spring is fixed, and the slider with an adjustable inclined plane moves along the smooth horizontal plane under the action of force F, and the other end of the spring can move along the vertical direction under the push of the inclined plane. By adjusting the angle θ between the inclined plane and the horizontal plane, the slider can have different compression amounts under the same horizontal displacement, thereby indirectly changing the output stiffness of the system.

[0046] For the variable slope and variable transmission ratio principle, the transmission ratio of the system is defined as the slope of the inclined plane i = tanθ, and the partial derivative of the force F acting on the block with respect to the horizontal displacement of the block is the output stiffness K of the system J ,and:

[0047]

[0048] The output stiffness of the system at this time is derived by calculating the micro-displacement method. Assuming that the magnitude of the external force F increases by ΔF, the corresponding displacement of the block increases by Δx, and the length of the spring is compressed by Δl. When the displacement of the block is very small, the average stiffness of the system in this process can be regarded as the output stiffness of the system. The displacement of the slider is regarded as the displacement of the entire system, and it is assumed that the work done by the external force in this process is all converted into the elastic potential energy of the spring. According to the law of conservation of energy, the following relationship exists:

[0049]

[0050] The transmission ratio of the system can be expressed as:

[0051]

[0052] The compression of the linear spring is affected by the transmission ratio of the system. At this time, the relationship between the output stiffness of the system and the transmission ratio is:

[0053] K J =i 2 K S =tan 2 θK S

[0054] Therefore, the output stiffness of the system can be changed by changing the slope of the inclined plane and thus changing the transmission ratio of the system. The range of the output stiffness is affected by the range of the slope change of the inclined plane. Because the transmission ratio is i=tanθ, when θ is less than 45°, the transmission ratio of the system can be less than 1; when θ is close to 90°, the transmission ratio of the system can theoretically approach infinity. It can be seen that the variable transmission ratio method by changing the slope of the inclined plane has a large stiffness adjustment range and can adapt to more application scenarios.

[0055] This embodiment is based on the translational variable slope, and obtains the mechanism of rotational variable slope and variable stiffness, thereby obtaining a flexible mechanism. Specifically, Figure 2As shown, the flexible mechanism of this embodiment includes a track assembly and a flexible assembly. The track assembly includes a first track 11 and a second track 13. The first track 11 is provided with a first slider 12 that slides with the first track 11, and the second track 13 is provided with a second slider 14 that slides with the second track 13. The flexible assembly of this embodiment includes a traction rod 15 that rotates around a fixed axis, and the second slider 14 slides with the traction rod 15. A spring 16 is provided between the first slider 12 and the second slider 14. When the position of the first slider 12 in the first track 11 remains stationary, the angle between the axis of the traction rod 15 and the spring 16 remains unchanged during the movement of the second slider 14 along the second track 13; but the angle between the axis of the traction rod 15 and the spring 16 changes as the first slider 12 slides along the first track 11. Specifically, the first track 11 is a circular track or a linear track. In this embodiment, the first track 11 is a circular track. Of course, in other embodiments, the first track 11 can also adopt track structures of other shapes, which will not be repeated.

[0056] The principle of the flexible mechanism of this embodiment is described below.

[0057] According to the characteristics of variable slope and variable transmission ratio in translational motion, this embodiment changes the way the external force acting on the slider is generated from horizontal action to traction by the traction rod 15, and at the same time changes the slope changing method from direct variable slope to indirect variable slope.

[0058] exist Figure 3 In the figure, a coordinate system XOY is established with the axis of the fixed shaft as the origin O, OB' is the traction rod 15, and the left side of the Y axis is the active stiffness adjustment part. When one end B or B' of the spring 16 remains stationary (that is, the position of the second slider 14 on the second track 13 remains stationary), the angle between the spring 16 and the traction rod 15 is changed by rotating the other end of the spring 16 (that is, the first slider 12 moves from point A to A' along the first track 11), thereby changing the transmission ratio of the configuration mechanism, that is, changing the output stiffness of the flexible mechanism.

[0059] When one end A or A' of the spring remains stationary (i.e., the position of the first slider 12 on the first track 11 remains stationary), the other end of the spring 16 moves along the second track 13 under the traction of the traction rod 15 (i.e., the second slider 14 moves from B to B' along the second track 13). During this process, the stretched length of the spring 16 is different, and the corresponding force acting on the linear spring is also different, and the torque output by the system is also different, but the angle between the axis of the spring 16 and the traction rod 15 remains unchanged, that is, during this process, the output stiffness of the flexible mechanism remains unchanged.

[0060] Specifically, this embodiment designs the shape of the center line of the second track 13 with the linear output of the joint torque as the goal. The coordinates of the points on the center line of the second track 13 corresponding to the target output torque at different joint angles are calculated respectively, and the set of calculated points is fitted to obtain the center line of the second track 13. The design process of the center line of the second track 13 is mainly: demand analysis → establishment of joint parameter relationship equation → calculation of the coordinates of the finite points on the contour curve and fitting of the contour curve.

[0061] (1) Demand Analysis:

[0062] The configuration mechanism designed in this embodiment will be applied to the knee joint of Dogotix, a quadruped robot developed by Shenzhen Duogou Robotics. Figure 4 shown.

[0063] Dogotix is ​​a quadruped robot weighing about 10.5Kg. When standing, the output torque of the knee joint motor is about 3.75N·m. When the quadruped robot is running, the maximum foot-end pressure can reach 3 times the body's own weight. In order to ensure that the maximum knee joint output torque for stable movement of the body is within the range of the flexible joint output torque, the maximum output torque of the flexible joint is selected as T=15N·m, and the range of motion of the joint angle β is 0~40° to design the contour line of the inclined surface. In order to maximize the use of the space of the mechanism, three identical flexible mechanisms are evenly distributed in a ring in the flexible joint designed in this embodiment. Therefore, it is only necessary to design the center line of the second track 13 of one of the flexible mechanisms. The output stiffness of the flexible mechanism is:

[0064]

[0065] The relationship between the output torque and joint angle of a single variable stiffness mechanism:

[0066] T J =K J β

[0067] (2) Establishment of parameter relationship equation:

[0068] Flexible structures such as Figure 2 As shown. E and E S They are respectively the input energy of the flexible mechanism and the energy stored in the spring when the traction rod 15 rotates through an angle β:

[0069] E=∫T J dβ

[0070]

[0071] Wherein, L represents the length of the spring 16 after the traction rod 15 rotates by an angle β; r represents the length of the spring 16 before the traction rod 15 rotates by an angle β; and k represents the elastic coefficient of the spring 16.

[0072] Assuming that all the input energy is converted into the elastic potential energy of the spring 16, the law of conservation of energy shows that E is approximately equal to E S :

[0073] E=E s

[0074] Specifically, Figure 2 As shown, The first track 11 is a circular track with O2 as the center and r as the radius. The first slider 12 can slide in the circular groove under the traction of the rod O2A. The angle between the initial position and the Y axis is α', and the range of motion is α". The initial length of the spring 16 is r, and the elastic stiffness is K. S One end of the spring 16 is fixed on the first slider 12, and the other end is fixed on the second slider 14. When the fixed axis rotates, the rod O2A remains stationary, and the other end of the spring moves along the curve under the traction of the second slider 14. (i.e. the second track 13) moves, at which time the spring 16 is stretched to a length of L. The second slider 14 can move along the curve under the traction of the rod O1B. Move, the moving range is β'. The length of O1B is R, the length of O1O2 is R0, and the length of the line connecting O1 and point A is l b The equivalent stiffness of the flexible mechanism is K J The geometric relationship between the various rods of the flexible mechanism is shown below:

[0075] r 2 +R0 2 -l b 2 =2rR0 cos(α'+α)

[0076] l b 2 +R0 2 -r 2 =2l b R0cosλ

[0077] l b 2 +R 2 -L 2 =2l b Rcos(β+λ)

[0078] With O1 as the origin and O1O2 as the Y axis, a rectangular coordinate system XOY is established, and the relationship between the real-time position of point B in the rectangular coordinate and the rotation angle β of the traction rod 15 relative to the Y axis and the length of O1B can be obtained:

[0079]

[0080] (3) Calculate the coordinates of the finite points on the contour curve and fit the contour curve:

[0081] The diameter of the knee joint motor of the quadruped robot Dogotix is ​​95mm. In order to avoid interference between the flexible joint and the robot body when the joint rotates, after multiple calculations and considerations, the values ​​of some dimensional parameters of the flexible joint are defined as shown in Table 1:

[0082] Table 1 Dimensional parameters of joint mechanism

[0083]

[0084] In order to make the joint torque output corresponding to as many α as possible linear, the coordinates of the finite point on the center line of the second track 14 are calculated when α=20°. Specifically, the rod O2A is slid to the first track 11 (i.e., the arc curve ) is fixed in the middle position, and the rod O1B is rotated clockwise from the initial position Y axis. The position (x, y) of point B in the rectangular coordinate system is calculated and recorded every 0.5°. Table 2 shows the position of point B recorded every 5°. Based on the calculated position of point B at 81 corresponding angles, Matlab mathematical software is used to fit the data, and the position of point B and the fitting curve are (i.e. the center line of the second track 14) Figure 5 shown.

[0085] Table 2 The position of point B at different rotation angles

[0086]

[0087] The fitted curve (i.e., the center line of the second track 14) is expressed as follows in a rectangular coordinate system:

[0088] f(x)=-0.00044x 3 -0.0085x 2 -0.4286x+50.0168

[0089] According to the solved curve The function expression of the second track 14 centerline in the rectangular coordinate system is used to inversely calculate the joint variable stiffness control function. The rod O2A is rotated from the initial position α', and stops every 2°. The joint torque output curve corresponding to the rod O2A at this position is solved according to the geometric relationship between the various parameters of the joint mechanism. The geometric relationship between the various parameters of the joint mechanism is as follows:

[0090] r 2 +R0 2 -l b 2=2rR0 cos(α+α')

[0091] l b 2 +R0 2 -r 2 =2l b R0cosλ

[0092] l b 2 +R 2 -L 2 =2l b Rcos(λ+β)

[0093] L 2 +R 2 -l b 2 =2LRcosγ1

[0094]

[0095]

[0096] ΔL=Lr

[0097] Among them, λ represents the angle between O1A and O1O2; γ1 represents the angle between the spring axis AB and the traction rod O1B; γ2 represents the angle between the spring axis AB and O1O2; Denotes the normal force F n With spring tension F S The angle between Representation force F τ With spring tension F S The angle between represents the derivative function of f(x); θ τ It represents the angle between the slope of any point of f(x) and the X-axis.

[0098] The force acting on the joint mechanism at point B (second slider 14) is analyzed. The tension F of the spring 16 is S , the torque on the joint is equivalent to the force F at point B τ and the normal force F perpendicular to the tangent line of the center line of the second track 14 at point B n The relationship between the three is as follows: Figure 2 As shown in the lower right corner. When the system reaches equilibrium, the resultant force of the three forces is equal to zero, so the expression between the three forces is:

[0099]

[0100] The output torque is:

[0101] T=Fτ R

[0102] The joint torque output curves corresponding to each α obtained by Matlab software are as follows: Figure 6 As shown. It can be found that at each angle of rotation of rod O2A (spring 16), the output torque of the joint basically changes linearly. Now take the average slope of each output torque curve, that is, the corresponding joint output stiffness, and record it as shown in Table 3.

[0103] Table 3 Average output stiffness of joints at different rotation angles

[0104]

[0105] According to the average output stiffness of the joints at different rotation angles in Table 3, data fitting is performed. The functional relationship between the output stiffness of a single variable stiffness structure and the control angle of the variable stiffness structure after fitting is as follows:

[0106]

[0107] The specific implementation of the flexible device of this embodiment is described in detail below in conjunction with the above-mentioned flexible mechanism.

[0108] like Figure 7 As shown, the flexible device of this embodiment includes a curved groove disk 21 and a central axis 22 that rotates with the curved groove disk 21, and at least two flexible mechanisms as described above are evenly distributed in an annular manner on the curved groove disk 21. Specifically, three flexible mechanisms are evenly distributed in an annular manner on the curved groove disk 21 of this embodiment. Of course, according to actual needs, the number of flexible mechanisms can also be set to 4 or more, which will not be repeated. Specifically, the first track 11 and the second track 13 are arranged on the curved groove disk 21, the fixed axis is coaxial with the central axis 22, and the traction rod 15 rotates synchronously with the central axis 22. The flexible device of this embodiment also includes a stiffness adjustment mechanism for driving the first slider 12 to slide along the first track 11 to change the angle between the traction rod 15 and the axis of the spring 16.

[0109] Specifically, the stiffness adjustment mechanism of this embodiment includes a stiffness adjustment disk 23 that is rotatably matched with the central axis 22 and a stiffness adjustment driving mechanism for driving the stiffness adjustment disk 23 to rotate. The stiffness adjustment disk 23 is provided with an adjustment track 24 corresponding to the first slider 12. In the viewing direction along the axis of the central axis 22, the adjustment track 24 intersects with the corresponding first track 11; the first slider 12 is slidably matched with the adjustment track 24. That is, the first slider 12 is located at the intersection of the adjustment track 24 and the first track 11. When the stiffness adjustment disk 23 rotates relative to the curved groove disk 21, the intersection position between the adjustment track 24 and the first track 11 changes, so that the position of the first slider 12 on the first track 11 can be adjusted, and the output stiffness of the flexible device can be further adjusted.

[0110] Furthermore, the stiffness adjustment drive mechanism can be implemented in a variety of existing ways. The stiffness adjustment drive mechanism of this embodiment includes an adjustment motor 25 installed on the curved groove disk 21, and a gear transmission mechanism for driving the stiffness adjustment disk 23 to rotate around the central axis 22 is provided between the output shaft of the adjustment motor 25 and the stiffness adjustment disk 23. The gear transmission mechanism of this embodiment includes a driving gear 26 arranged on the output shaft of the adjustment motor 25 and a passive gear 27 arranged on the outer peripheral wall of the stiffness adjustment disk 23 and meshing with the driving gear 26. Specifically, the adjustment motor 25 of this embodiment adopts a stepping motor, and the stepping motor model is 24BYJ48, which complies with the principle of lightweight, the module of the driving gear 26 is 1mm, the number of teeth is 17, and the number of teeth of the passive gear arranged on the stiffness adjustment disk 23 is 94.

[0111] Furthermore, the curved groove disc 21 is provided with a center sleeve 28 that is rotatably fitted on the central shaft 22, the rigidity adjustment disc 23 is rotatably fitted on the center sleeve 28, and a limit plate for preventing the rigidity adjustment disc 23 from moving in the axial direction of the central shaft 22 is installed on the center sleeve 28, and the rigidity adjustment disc 23 is located between the limit plate and the curved groove disc 21, so that the rigidity adjustment disc 23 can be prevented from moving in the axial direction of the central shaft 22 relative to the curved groove disc 21. In the preferred solution of this embodiment, a grating encoder 30 is installed on the center sleeve 28, and a grating encoder disc 31 that rotates synchronously therewith is provided on the central shaft 22 to detect the deflection angle between the central shaft 22 and the curved groove disc 21.

[0112] Further, a protective plate 32 is provided on the side of the curved groove plate 21 of the present embodiment facing away from the stiffness adjustment plate 23, and the flexible component is located between the curved groove plate 21 and the protective plate 32 to protect the flexible component. Of course, in some other embodiments, the flexible component can also be arranged between the curved groove plate 21 and the stiffness adjustment plate 23, and the protective plate 32 can be arranged separately at this time. In the preferred scheme of the present embodiment, a first auxiliary track 33 and a second auxiliary track 34 are arranged on the protective plate 32, and the first auxiliary track 33 is arranged in a one-to-one correspondence with the first track 11, and the second auxiliary track 34 is arranged in a one-to-one correspondence with the second track 13; in the viewing direction along the axis of the central axis 21, the center line of the first auxiliary track 33 coincides with the center line of the corresponding first track 11, and the center line of the second auxiliary track 34 coincides with the center line of the second track 13, and at this time, the first slider 12 can be slidably matched with the first track 11 and the first auxiliary track 33 at the same time, so that the movement of the first slider 12 is more stable. At the same time, the second slider 14 can also be slidably matched with the second track 13 and the second auxiliary track 34 at the same time, so that the movement of the second slider 14 is more stable, which will not be repeated.

[0113] like Fig. 9As shown, the flexible device of this embodiment also includes an outer shell, which includes a cylinder 35 and a cylinder cover 36. The curved groove disk 21, the stiffness adjustment disk 23 and the protection disk 32 are all installed in the cylinder 35, and the cylinder 35 and the cylinder cover 36 are respectively provided with a first through hole 37 and a second through hole 38 corresponding to the central axis 22.

[0114] The flexible joint of the present embodiment is provided with a curved groove disk 21, and the first track 11 and the second track 13 are provided on 21, the first slider 12 of the flexible component is slidably matched with the first track 11, and the second slider 14 is slidably matched with the second track 13. In this way, when the stiffness adjustment disk 23 is driven to rotate by the adjustment motor 25, the first slider 12 can be driven to move along the first track 11, thereby changing the angle between the axis of the spring 16 and the traction rod 15, that is, changing the output stiffness of the flexible joint; since the flexible mechanism of the present embodiment is evenly distributed with three flexible mechanisms in an annular shape, that is, the variable stiffness control function of the flexible joint 3 times Right now:

[0115]

[0116] The variable stiffness control curve of the entire flexible joint is as follows: Fig.15 shown.

[0117] When the output rigidity is adjusted to a suitable value, if the central shaft 22 rotates relative to the curved groove plate 21, the traction rod 15 will be driven to rotate, and the rotation of the traction rod 15 will drive the second slider 14 to move along the second track 13. Although the angle between the axis of the spring 16 and the traction rod 15 will not change at this time, the length of the spring 16 will change, that is, the elastic force of the spring 16 will change, and the torque applied by the spring 16 to the traction rod 15 will change linearly, so that linear torque output can be achieved.

[0118] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A flexible mechanism, characterized in that: Includes a track assembly and a flexible assembly; The track assembly comprises a first track and a second track, wherein a first slider is provided in the first track for sliding cooperation therewith, and a second slider is provided in the second track for sliding cooperation therewith; The flexible component includes a traction rod rotating around a fixed axis, the second slider is slidably matched with the traction rod, and a spring is provided between the first slider and the second slider; When the first slider remains stationary in the first track, the angle between the traction rod and the axis of the spring remains unchanged during the movement of the second slider along the second track; and: The angle between the traction rod and the axis of the spring changes as the first sliding block slides along the first track.

2. The flexible mechanism according to claim 1, characterized in that: The first track is a circular track or a straight track.

3. A flexible device, characterized in that: It comprises a curved groove plate and a central shaft that rotates with the curved groove plate, at least two flexible mechanisms as claimed in claim 1 or 2 are evenly distributed in an annular pattern on the curved groove plate, the first track and the second track are arranged on the curved groove plate, the fixed shaft is coaxial with the central shaft, and the traction rod rotates synchronously with the central shaft; Also included is a stiffness adjustment mechanism for driving the first slider to slide along the first track to change the angle between the traction rod and the axis of the spring; The stiffness adjustment mechanism comprises a stiffness adjustment disk rotatably matched with the central shaft and a stiffness adjustment driving mechanism for driving the stiffness adjustment disk to rotate; the stiffness adjustment disk is provided with adjustment tracks corresponding to the first sliders one by one, and in the viewing direction along the axis of the central shaft, the adjustment tracks intersect with the corresponding first tracks; The first sliding block is slidably matched with the adjusting track.

4. The flexible device according to claim 3, characterized in that: The stiffness adjustment driving mechanism comprises an adjustment motor installed on the curved groove disk, and a gear transmission mechanism for driving the stiffness adjustment disk to rotate around the central axis is provided between the output shaft of the adjustment motor and the stiffness adjustment disk.

5. The flexible device according to claim 4, characterized in that: The gear transmission mechanism comprises a driving gear arranged on the output shaft of the adjusting motor and a driven gear arranged on the outer peripheral wall of the stiffness adjusting disk and meshing with the driving gear.

6. The flexible device according to claim 3, characterized in that: The curved groove disk is provided with a center sleeve that is rotatably fitted on the center axis, the stiffness adjustment disk is rotatably fitted on the center sleeve, and the center sleeve is provided with a limit disk for preventing the stiffness adjustment disk from moving along the axial direction of the center axis, and the stiffness adjustment disk is located between the limit disk and the curved groove disk.

7. The flexible device according to claim 6, characterized in that: A grating encoder is installed on the central sleeve, and a grating encoder disk which rotates synchronously with the central shaft is provided on the central shaft.

8. The flexible device according to claim 3, characterized in that: The flexible component is located between the curved groove plate and the stiffness adjustment plate; or, a protective plate is provided on the side of the curved groove plate facing away from the stiffness adjustment plate, and the flexible component is located between the curved groove plate and the protective plate.

9. The flexible device according to claim 8, characterized in that: The protection plate is provided with a first auxiliary track and a second auxiliary track, the first auxiliary track is arranged in a one-to-one correspondence with the first track, and the second auxiliary track is arranged in a one-to-one correspondence with the second track; in the viewing direction along the axis of the central axis, the center line of the first auxiliary track coincides with the center line of the corresponding first track, and the center line of the second auxiliary track coincides with the center line of the second track.

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