Variable stiffness damper and method of controlling the same

Abstract

The application provides a variable stiffness damper, which comprises a shell, a ball, a driving assembly, a damping assembly and an adjusting assembly. The ball is accommodated in the shell. The driving assembly comprises an input member and a first transmission member. The input member is assembled in the shell and is used for receiving vibration force generated by an external machine. The first transmission member is rotatably installed in the shell and can rotate under the drive of the input member to drive the ball to rotate. The damping assembly comprises a second transmission member and an output member. The second transmission member is rotatably installed in the shell and is configured to rotate under the drive of the ball. The output member is assembled in the second transmission member. The rotation axis of the first transmission member and the rotation axis of the second transmission member intersect. The adjusting assembly is installed in the shell and is used for adjusting the rotation axis of the ball. The application also provides a control method of the variable stiffness damper. According to the vibration frequency of the target to be damped, the first rotation axis is rotated to a specified angle, so that the damping frequency of the variable stiffness damper is consistent with the vibration frequency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of robot damping, and particularly relates to a variable stiffness damper and a control method thereof. BACKGROUND

[0002] With the rapid development of the science and technology level and the industrialization degree, with the increase of the power of a machine or equipment, the rotor speed is accelerated, and thus the vibration and noise generated are also increasing. During the operation of the machine or equipment, the vibration frequency is prone to change under the influence of the change of the working condition of the machine or equipment itself or the external environment. In the related art, a damper is used to reduce the vibration. However, the damping frequency of the damper is fixed, which leads to the poor damping effect of the damper. SUMMARY

[0003] The application aims to provide a variable stiffness damper and a control method thereof, so as to solve the technical problem of the poor damping effect of the damper caused by the fixed damping frequency of the damper in the prior art.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the application is as follows: a variable stiffness damper is provided, comprising:

[0005] a housing;

[0006] a ball body accommodated in the housing;

[0007] a driving assembly, the driving assembly comprising an input member and a first transmission member, the input member being assembled to the housing and being used to receive the vibration force generated by an external machine, the first transmission member being rotatably installed on the housing and being configured to be able to rotate under the driving of the input member to drive the ball body to rotate;

[0008] a damping assembly, the damping assembly comprising a second transmission member and an output member, the second transmission member being rotatably installed on the housing and being configured to be able to rotate under the driving of the ball body, the output member being assembled to the second transmission member and being used to output the vibration force; wherein the rotation axis of the first transmission member and the rotation axis of the second transmission member intersect;

[0009] an adjusting assembly, the adjusting assembly being installed on the housing and being configured to be used to adjust the rotation axis of the ball body.

[0010] Optionally, the adjusting assembly comprises an adjusting member and a driver, the driver being fixedly installed on the housing, the adjusting member being fixedly installed on the output end of the driver and being able to rotate under the action of the driver.

[0011] Optionally, the adjusting member comprises a first adjusting unit and at most two second adjusting units, the first adjusting unit is fixedly installed at the output end of the driver and can rotate under the driving of the driver, and the at most two second adjusting units are respectively assembled at two ends of the first adjusting unit and can rotate under the driving of the first adjusting unit.

[0012] Optionally, the first adjusting unit comprises a first rotating shaft and at most two first bevel gears, the first rotating shaft is fixedly installed at the driver and can rotate under the driving of the driver, and the at most two first bevel gears are respectively fixedly installed at two ends of the first rotating shaft.

[0013] Optionally, the second adjusting unit comprises a second rotating shaft, a second bevel gear and a first roller, the second bevel gear is fixedly installed at the second rotating shaft and is engaged with the first bevel gear, the first roller is hingedly connected to one end of the second rotating shaft close to the ball and can rotate under the driving of the ball; wherein the rotation axis of the second rotating shaft is different from the rotation axis of the first transmission member and is different from the rotation axis of the second transmission member.

[0014] Optionally, the first adjusting unit further comprises a first fixing seat, the first fixing seat is installed at the shell, and the first rotating shaft is rotatably penetrated in the first fixing seat; the second adjusting unit further comprises a second fixing seat, the second fixing seat is installed at the shell, and the second rotating shaft is rotatably penetrated in the second fixing seat.

[0015] Optionally, the input member comprises an input gear and an input rack, the input gear is fixedly installed at the first transmission member, and the input rack is engaged with the input gear; the first transmission member comprises a first transmission shaft and a second roller, the first transmission shaft is fixedly installed at the input gear and can rotate under the driving of the input gear, and the second roller is fixedly installed at one end of the first transmission shaft close to the ball and can rotate along with the first transmission shaft.

[0016] Optionally, the second transmission member comprises a second transmission shaft and a third roller, the third roller is fixedly installed at one end of the second transmission shaft close to the ball and can rotate under the driving of the ball; the output member comprises an output gear, an output rack and an elastic structure, the output gear is fixedly installed at the second transmission shaft and can rotate along with the second transmission shaft, the output rack is engaged with the output gear, and the elastic structure is abutted between the output rack and the shell.

[0017] Optionally, the driving assembly further comprises a third fixing seat fixedly installed on the shell, and the first transmission shaft is rotatably arranged in the third fixing seat; the damping assembly further comprises a fourth fixing seat fixedly installed on the shell, and the second transmission shaft is rotatably arranged in the fourth fixing seat.

[0018] The application further provides a robot comprising the variable stiffness damper and a robot body, wherein the variable stiffness damper is assembled on the robot body.

[0019] The application further provides a control method of the variable stiffness damper, comprising at least the following steps:

[0020] detecting a vibration frequency of a target to be damped;

[0021] feeding back the vibration frequency to a controller;

[0022] controlling the output end of the driver to rotate to a specified angle according to the vibration frequency.

[0023] The variable stiffness damper provided by the application has the following beneficial effects:

[0024] The variable stiffness damper provided by the application can reduce the vibration force by reducing the speed and increasing the torque of the input member and the first transmission member under the joint action of the ball, the second transmission member and the output member. When the vibration frequency of the external machine or device changes, the adjusting assembly can adjust the rotation axis of the ball according to the vibration frequency of the external machine or device, so as to change the transmission ratio between the first transmission member and the second transmission member, and further change the damping frequency of the variable stiffness damper, so that the damping frequency of the variable stiffness damper is consistent with the vibration frequency, thereby causing resonance and achieving good damping effect.

[0025] The robot provided by the application has the following beneficial effects:

[0026] The robot provided by the application can effectively eliminate the vibration generated by the robot body by the variable stiffness damper, and can adjust the damping frequency according to the vibration frequency of the robot body, thereby achieving good damping effect and prolonging the service life of the robot body.

[0027] The control method of the variable stiffness damper provided by the application has the following beneficial effects:

[0028] The control method of the variable stiffness damper provided by the application can control the first rotation axis to rotate to a specified angle according to the vibration frequency of the target to be damped, so that the damping frequency of the variable stiffness damper is consistent with the vibration frequency. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0030] Figure 1 A first perspective view of the variable stiffness damper provided by the embodiments of the present application;

[0031] Figure 2 A second perspective view of the variable stiffness damper provided by the embodiments of the present application;

[0032] Figure 3 A flow chart of the variable stiffness damper control method provided by the embodiments of the present application;

[0033] Figure 4 A first coordinate system schematic diagram of the variable stiffness damper provided by the embodiments of the present application;

[0034] Figure 5 A second coordinate system schematic diagram of the variable stiffness damper provided by the embodiments of the present application;

[0035] Figure 6 A third coordinate system schematic diagram of the variable stiffness damper provided by the embodiments of the present application;

[0036] Figure 7 A fourth coordinate system schematic diagram of the variable stiffness damper provided by the embodiments of the present application.

[0037] In the drawings, various reference signs represent:

[0038] 1, sphere;

[0039] 2, driving assembly; 21, input member; 211, input gear; 212, input rack; 22, first transmission member; 221, first transmission shaft; 222, second roller;

[0040] 3, damping assembly; 31, second transmission member; 311, second transmission shaft; 312, third roller; 32, output member; 321, output gear; 322, output rack; 323, elastic structure;

[0041] 4, adjusting assembly; 41, adjusting member; 411, first adjusting unit; 4111, first rotation shaft; 4112, first bevel gear; 412, second adjusting unit; 4121, second rotation shaft; 4122, second bevel gear; 4123, first roller. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0043] It should be noted that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or indirectly connected to the other element.

[0044] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element 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.

[0045] In addition, the terms "first", "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0046] Based on this, the present application provides a variable stiffness damper and a robot, which can be adjusted according to the vibration frequency of the machine or device, so that the damping frequency of the damper and the vibration frequency of the machine or device remain consistent, which helps to improve the damping effect of the damper.

[0047] As Figure 1 and Figure 2As shown, the embodiment of the present application provides a variable stiffness shock absorber, which comprises a shell (not shown in the figure), a ball 1, a driving assembly 2, a damping assembly 3 and an adjusting assembly 4. The ball 1 is accommodated in the shell. The driving assembly 2 comprises an input member 21 and a first transmission member 22. The input member 21 is assembled in the shell and is used to receive the vibration force generated by an external machine. The first transmission member 22 is rotatably installed in the shell and is configured to be able to rotate under the driving of the input member 21 to drive the ball 1 to rotate. The damping assembly 3 comprises a second transmission member 31 and an output member 32. The second transmission member 31 is rotatably installed in the shell and is configured to be able to rotate under the driving of the ball 1. The output member 32 is assembled in the second transmission member 31 and is used to output the vibration force. Wherein, the rotation axis of the first transmission member 22 and the rotation axis of the second transmission member 31 intersect. The adjusting assembly 4 is installed in the shell and is configured to be used to adjust the rotation axis of the ball 1. It needs to be pointed out here that the intersection of the rotation axis of the first transmission member 22 and the rotation axis of the second transmission member 31 means that the rotation axis of the first transmission member 22 and the rotation axis of the second transmission member 31 are staggered and form an included angle.

[0048] Wherein, in the embodiment, the included angle between the rotation axis of the first transmission member 22 and the rotation axis of the second transmission member 31 is set to 90°. Of course, in other embodiments, according to the actual application requirements, the included angle between the rotation axis of the first transmission member 22 and the rotation axis of the second transmission member 31 can also be set to other degrees, which is not limited here.

[0049] Specifically, in use of the device, the vibration force generated by the external machine or equipment acts on the input member 21. The input member 21 reciprocates under the action of the vibration force, and the first transmission member 22 rotates under the action of the input member 21. By using the friction force between the first transmission member 22 and the ball 1, the first transmission member 22 can drive the ball 1 to rotate. At this time, the rotation axis of the ball 1 is consistent with the rotation axis between the first transmission member 22. Since the rotation axis of the first transmission member 22 and the rotation axis of the second transmission member 31 intersect, the rotation axis of the ball 1 and the rotation axis of the second transmission member 31 intersect, so that the ball 1 cannot directly drive the second transmission member 31 to rotate, thereby causing the rotation speed of the second transmission member 31 to be less than the rotation speed of the first transmission member 22, and further achieving damping.

[0050] More specifically, the variable stiffness damper further comprises an external controller, and the adjusting assembly 4 is electrically connected to the external controller. It needs to be explained here that in this embodiment, the external controller is set as a PID controller (i.e. a proportional-integral-derivative controller). Of course, in other embodiments, the external controller can also be set as other control devices according to actual application requirements, which is not limited here. When the vibration frequency of the external machine or device changes, the external controller controls the adjusting assembly 4 to adjust the rotation axis of the ball 1, so as to change the relative position between the rotation axis of the ball 1 and the rotation axis of the second transmission member, and further change the rotation speed of the second transmission member.

[0051] The variable stiffness damper provided in the application can slow down and increase the torque of the input member 21 and the first transmission member 22 under the joint action of the ball 1, the second transmission member 31 and the output member 32, so as to buffer the vibration force. When the vibration frequency of the external machine or device changes, the adjusting assembly 4 can adjust the rotation axis of the ball 1 according to the vibration frequency of the external machine or device, so as to change the transmission ratio between the first transmission member 22 and the second transmission member 31, and further change the damping frequency of the variable stiffness damper, so that the damping frequency of the variable stiffness damper is consistent with the vibration frequency, so that resonance occurs, which helps to enhance the damping effect of the variable stiffness damper.

[0052] In an embodiment of the application, please refer to Figure 1 and Figure 2 The adjusting assembly 4 comprises an adjusting member 41 and a driver (not shown in the figure), and the driver is fixedly installed on the shell, and the adjusting member 41 is fixedly installed on the output end of the driver and can rotate under the action of the driver.

[0053] Specifically, in this embodiment, the driver is set as an electric motor as an example for description. The adjusting member 41 is fixedly installed on the output shaft of the electric motor, and the adjusting member 41 can rotate under the driving of the electric motor, so as to change the rotation axis of the adjusting member 41.

[0054] In this way, the driver can drive the adjusting member 41 to rotate, and the rotation axis of the ball 1 can be changed under the action of the adjusting member 41, so as to change the relative position between the rotation axis of the ball 1 and the rotation axis of the second transmission member 31, and further change the relative position between the first transmission member 22 and the second transmission member 31.

[0055] In an embodiment of the application, please refer to Figure 1 and Figure 2The adjusting member 41 comprises a first adjusting unit 411 and at most two second adjusting units 412. The first adjusting unit 411 is fixedly installed on the output end of the driver and can rotate under the driving of the driver. The at most two second adjusting units 412 are respectively assembled on the two ends of the first adjusting unit 411 and can rotate under the driving of the first adjusting unit 411.

[0056] It should be noted that in the embodiment, the number of the second adjusting units 412 is set to two. Of course, in other embodiments, the number of the second adjusting units 412 can also be set to one according to actual application requirements.

[0057] Specifically, in the embodiment, the two second adjusting units 412 are respectively engaged with the two ends of the first adjusting unit 411. The driver drives the first adjusting unit 411 to rotate, and the two second adjusting units 412 rotate under the driving of the first adjusting unit 411, so as to change the rotation axis of the second adjusting unit 412.

[0058] In this way, the at most two second adjusting units 412 rotate under the driving of the first adjusting unit 411, so as to change the rotation axis of the second adjusting unit 412. By changing the rotation axis of the second adjusting unit 412, the rotation axis of the sphere 1 can be changed, so that the relative position between the rotation axis of the sphere 1 and the rotation axis of the second transmission member 31 is changed, thereby the transmission ratio between the first transmission member 22 and the second transmission member 31 can be changed, so that the damping frequency of the damping assembly 3 and the vibration frequency of the external machine are kept consistent. In addition, compared with the case that the number of the second adjusting units 412 is one, the number of the second adjusting units 412 is two, and the rotation axis of the sphere 1 is adjusted by the two second adjusting units 412, which is convenient for adjusting the rotation axis of the sphere 1 and helps to improve the convenience of use.

[0059] In an embodiment of the present application, referring to Figure 1 and Figure 2 The first adjusting unit 411 comprises a first rotation shaft 4111 and at most two first bevel gears 4112. The first rotation shaft 4111 is fixedly installed on the driver and can rotate under the driving of the driver. The at most two first bevel gears 4112 are respectively fixedly installed on the two ends of the first rotation shaft 4111. The second adjusting unit 412 comprises a second rotation shaft 4121, a second bevel gear 4122 and a first roller 4123. The second bevel gear 4122 is fixedly installed on the second rotation shaft 4121 and engaged with the first bevel gear 4112. The first roller 4123 is hingedly connected to the second rotation shaft 4121 close to the sphere 1 and can rotate under the driving of the sphere 1. The rotation axis of the second rotation shaft 4121 is different from the rotation axis of the first transmission member 22 and the rotation axis of the second transmission member 31.

[0060] It should be noted that the number of the first bevel gears 4112 is set to two in the embodiment. Of course, the number of the first bevel gears 4112 can also be set to one in other embodiments according to actual application requirements.

[0061] Specifically, the driver drives the first rotating shaft 4111 to rotate, the first rotating shaft 4111 drives the two first bevel gears 4112 to rotate, and the rotating axis of the first rotating shaft 4111 is consistent with the rotating axes of the two first bevel gears 4112. The first bevel gears 4112 drive the second bevel gears 4122 to rotate, the second bevel gears 4122 can drive the two second rotating shafts 4121 to rotate, and the rotating directions of the two second rotating shafts 4121 are opposite. The second rotating shafts 4121 can drive the first rollers 4123 to rotate. It should be noted that the first rollers 4123 can rotate with the second rotating shafts 4121, that is, the rotating axes of the first rollers 4123 are consistent with the rotating axes of the second rotating shafts 4121. At the same time, the first rollers 4123 can also roll along their own axes, that is, the rolling axes of the first rollers 4123 are perpendicular to the rotating axes of the first rollers 4123, so that the relative positions between the first rollers 4123 and the ball 1 can be changed.

[0062] In this way, under the actions of the first rotating shaft 4111, the first bevel gears 4112, the second bevel gears 4122 and the second rotating shafts 4121, the relative positions between the first rollers 4123 and the ball 1 can be changed, so that the relative positions between the rotating axis of the ball 1 and the second transmission member can be changed.

[0063] In one embodiment of the present application, please refer to Figure 1 and Figure 2 The first adjusting unit 411 further comprises a first fixing seat (not shown in the figure), the first fixing seat is installed on the shell, and the first rotating shaft 4111 is rotatably arranged in the first fixing seat. The second adjusting unit 412 further comprises a second fixing seat (not shown in the figure), the second fixing seat is installed on the shell, and the second rotating shaft 4121 is rotatably arranged in the second fixing seat.

[0064] In this way, the first fixing seat can fix the first rotating shaft 4111 to the shell, prevent the relative positions between the first rotating shaft 4111 and the shell from being changed, and the first rotating shaft 4111 can rotate relative to the first fixing seat. The second fixing seat can fix the second rotating shaft 4121 to the shell, prevent the relative positions between the second rotating shaft 4121 and the shell from being changed, and the second rotating shaft 4121 can rotate relative to the second fixing seat.

[0065] In one embodiment of the present application, please refer to Figure 1 and Figure 2The input member 21 comprises an input gear 211 and an input rack 212. The input gear 211 is fixedly installed on the first transmission member 22, and the input rack 212 is engaged with the input gear 211. The first transmission member 22 comprises a first transmission shaft 221 and a second roller 222. The first transmission shaft 221 is fixedly installed on the input gear 211 and can rotate under the driving of the input gear 211. The second roller 222 is fixedly installed on the first transmission shaft 221 near one end of the first transmission shaft 221 and can rotate along with the first transmission shaft 221. The second transmission member 31 comprises a second transmission shaft 311 and a third roller 312. The third roller 312 is fixedly installed on the second transmission shaft 311 near one end of the second transmission shaft 311 and can rotate under the driving of the sphere 1. The output member 32 comprises an output gear 321, an output rack 322, and an elastic structure 323. The output gear 321 is fixedly installed on the second transmission shaft 311 and can rotate along with the second transmission shaft 311. The output rack 322 is engaged with the output gear 321. The elastic structure 323 is arranged between the output rack 322 and the housing.

[0066] Specifically, in the embodiment, a three-dimensional coordinate system is established with the sphere center of the sphere 1 as the origin. In the embodiment, the first transmission shaft 221 and the second transmission shaft 311 are both located in the X-Y plane. The first transmission shaft 221 and the second transmission shaft 311 are arranged vertically. The included angle between the first transmission shaft 221 and the Y-axis and the included angle between the second transmission shaft 311 and the Y-axis are both 45°. The first rotation shaft 4111 and the two second rotation shafts 4121 are both located in the Y-Z plane. The two second rotation shafts 4121 are arranged vertically. The included angle between each second rotation shaft 4121 and the Y-axis and the included angle between each second rotation shaft 4121 and the first rotation shaft 4111 are both 45°.

[0067] More specifically, the vibration force of the external machine or device acts on the input rack 212. The input rack 212 transmits the vibration force to the input gear 211, which can be driven to rotate under the action of the input rack 212. The input gear 211 drives the first transmission shaft 221 to rotate. The rotation axis of the input gear 211 and the rotation axis of the first transmission shaft 221 are consistent. The first transmission shaft 221 drives the second roller 222 to rotate. The rotation axis of the second roller 222 and the rotation axis of the first transmission shaft 221 are consistent. The second roller 222 drives the sphere 1 to rotate. The sphere 1 drives the third roller 312 to rotate. The rotation axis of the third roller 312 intersects with the rotation axis of the second roller 222. The third roller 312 drives the second transmission shaft 311 to rotate. The second transmission shaft 311 drives the output gear 321 to rotate. The output gear 321 drives the output rack 322 to move. The elastic structure 323 can buffer the output rack 322.

[0068] It is noted that in order to link the steering angle of the damper with the transmission ratio between the second roller 222 and the third roller 312, a coordinate system is established, as shown in Figures 4 to 7 The driving assembly 2 and the damper assembly 3 are denoted as a d coordinate system. The dl axis points to the Dl roller, the d2 axis points to the D2 roller, and the d3 axis points to the negative direction of the Z axis. The adjusting assembly 3 is denoted as a c coordinate system. The cl axis points to the Sl roller, the c2 axis points to the S2 roller, and the c3 axis points to the negative direction of the X axis. According to the geometric relationship of the damper, the d coordinate system and the c coordinate system can be linked with each other by using a spherical coordinate system. It is known that the second roller Dl and the third roller D2 form a 45° angle with the Y axis, so the dl axis and the d2 axis form a 45° angle with the Y axis, and the d3 axis points to the negative direction of the Z axis. This relationship can be expressed as formula 1.

[0069]

[0070] Alternatively, it can be expressed as formula 2 by using a matrix.

[0071]

[0072] Similarly, the relationship between the c coordinate system and the spherical 1 coordinate system can be expressed as formula 3.

[0073]

[0074] Alternatively, it can be expressed as formula 4 by using a matrix.

[0075]

[0076] According to formula 2 and formula 4, the relationship formula 5 between the d coordinate system and the c coordinate system can be obtained.

[0077]

[0078] Z is the transformation matrix between the d coordinate system and the c coordinate system.

[0079] Figure 7 The directions of the two first rollers 4123, i.e., Sl and S2, are shown, where θ S1 The rotation of one of the first rollers 4123 is described, θ S2 The rotation of the other first roller 4123 is described, and ψ is the steering angle. Therefore, formula 6 can be obtained.

[0080] θ s1 = θ s1 cosψc2+ θ s1 sinψc3, θ s2 = θ s2 cosψc1+ θ s2 sinψc2

[0081] When the two first rollers 4123 rotate, i.e. S1 and S2 rotate, the tangential displacement caused by the contact between the surface of the first rollers 4123 and the sphere is expressed as formula 7:

[0082] P S1 = -rθ S1 sinψc2 + rθ S2 cosψc3, P S2 = rθ S2 sinψc1 - rθ S2 cosψc3

[0083] Where r is the radius of the first rollers 4123, i.e. the radius of S1 and S2.

[0084] The rotation of the sphere can also be expressed in the c coordinate system as formula 8:

[0085] Θ = Θ1c1 + Θ2c2 + Θ3c3

[0086] Where Θ1, Θ2, Θ3 are the rotation components in the directions of c1, c2, c3, respectively. Because the tangential displacement between the steering wheel and the contact surface of the sphere must be the same, using the definition of formula 8 above, formula 7 can be rewritten as formula 9:

[0087] P S1 = RΘ3c2 - RΘ2c3, P = -RΘ3c1 + RΘ1c3

[0088] By comparing formula 7 and formula 9, the relationship between the rolling of the first rollers 4123 and the rotation of the sphere can be found as formula 10:

[0089]

[0090] Alternatively, it can be directly expressed as formula 11:

[0091]

[0092] According to formula 10, we can get: S = θ S1 = θ S2 . Using the transformation matrix Z in formula 5 to transform the rotation Θ of the sphere 1 to the z coordinate system, we get formula 12:

[0093]

[0094] Equation 12 shows that the rotation of sphere 1 in the d coordinate system is a function of the steering angle ψ and describes how changing the steering angle affects the rotation of sphere 1 in the di and d2 directions. Another expression for the rotation of sphere 1 in the d coordinate system can also be derived by introducing new variables: the steering angle θ0of sphere 1, the rotation axis t of sphere 1, the angle γ between the rotation axis of sphere 1 and the d2 axis, and the rotation angles of the second and third rollers 222 and 312 (i.e., the rotation angles θ1and θ2of the drive wheels D1and D2). The rotational motion of sphere 1 about the t axis can be expressed as Equation 13:

[0095] θ0= θ0sin γ di + θ0cos γ d2

[0096] By combining Equation 12 and Equation 13, the relationship between ψ and γ can be obtained as Equation 14:

[0097]

[0098] In Equation 14, the angle γ is referred to as the transmission angle and is directly related to the transmission ratio between the two drive wheels (i.e., the second and third rollers 222 and 312), which can be used to describe the relative motion and torque relationship between the drive wheels of the vibration damper. Using the tangential displacement between the drive wheels and sphere 1, the relationship between the transmission ratio between the two drive wheels and the rotation angles θ1, θ2of the drive wheels can be derived. For the drive wheels, see Equation 15:

[0099] P D1 = -rθ1d3, P D2 = -rθ2d3

[0100] For sphere 1, see Equation 16:

[0101] P D1 = -Rθ0cos γ d3, P D2 = Rθ0sin γ d3

[0102] By combining Equation 15 and Equation 16, the relationship between the transmission angle γ and the rotation angles of the drive wheels can be obtained as Equation 17:

[0103]

[0104] Equation 17 shows that the ratio of the rotation angles of the drive wheels (θ1 / θ2) represents the transmission ratio of the vibration damper.

[0105] By combining Equation 14 and Equation 17, the relationship between the steering angle and the transmission ratio can be obtained as Equation 18:

[0106]

[0107] Thus, the rotation axis of the second roller 222 intersects with the rotation axis of the third roller 312, because the rotation axis of the first transmission shaft 221 intersects with the rotation axis of the second transmission shaft 311. In this way, the second roller 222 can directly drive the ball 1 to rotate, and the ball 1 cannot directly drive the third roller 312 to rotate. Therefore, the rotation speed of the first transmission shaft 221 is greater than the rotation speed of the second transmission shaft 311, the reciprocating frequency of the input rack 212 is faster than the reciprocating frequency of the output rack 322, and the damping can be achieved. Moreover, the relative position between the first roller 4123 and the ball 1 changes by controlling the rotation angle of the first rotation shaft 4111 according to the change of the vibration frequency, the rotation axis of the ball 1 is adjusted, the rotation speed of the third roller 312 is changed to adjust the reciprocating frequency of the output rack 322, and finally the damping frequency of the damper is adjusted, which helps to improve the damping effect of the damper.

[0108] Optionally, the elastic structure 323 is a spring or a spring sheet.

[0109] In an embodiment of the present application, referring to Figure 1 and Figure 2 , the driving assembly 2 further comprises a third fixed seat (not shown in the figure), which is fixedly installed on the shell, and the first transmission shaft 221 is rotatably arranged in the third fixed seat. The damping assembly 3 further comprises a fourth fixed seat (not shown in the figure), which is fixedly installed on the shell, and the second transmission shaft 311 is rotatably arranged in the fourth fixed seat.

[0110] Thus, the third fixed seat can fix the first transmission shaft 221 to the shell, prevent the relative position between the first transmission shaft 221 and the shell from changing, and allow the first transmission shaft 221 to rotate relative to the third fixed seat. The fourth fixed seat can fix the second transmission shaft 311 to the shell, prevent the relative position between the second transmission shaft 311 and the shell from changing, and allow the second transmission shaft 311 to rotate relative to the fourth fixed seat.

[0111] The present application also provides a robot, which comprises a variable stiffness damper and a robot body, and the variable stiffness damper is assembled to the robot body.

[0112] The robot provided by the present application can effectively eliminate the vibration generated by the robot body through the variable stiffness damper, and can adjust the damping frequency according to the vibration frequency of the robot body, so as to have a good damping effect and help to prolong the service life of the robot body.

[0113] As shown in Figure 3 , the present application also provides a control method of a variable stiffness damper, which at least comprises the following steps:

[0114] S1: detecting the vibration frequency of the target to be damped.

[0115] Specifically, the vibration frequency of the target to be damped is detected by the vibration frequency detector.

[0116] S2: feeding the vibration frequency to the controller.

[0117] Specifically, the vibration frequency detected by the vibration frequency detector is fed to the PID controller.

[0118] S3: the controller controls the output end of the driver to rotate to a specified angle according to the vibration frequency.

[0119] Specifically, the PID controller processes the data of the vibration frequency fed by the vibration frequency detector and feeds the signal to the driver. The output end of the driver controls the first rotating shaft 4111 to rotate to a specified angle.

[0120] The control method of the variable stiffness damper provided in the present application can control the first rotating shaft 4111 to rotate to a specified angle according to the vibration frequency of the target to be damped, so that the damping frequency of the variable stiffness damper is consistent with the vibration frequency.

[0121] One or more embodiments of the present application are intended to cover all such alternatives, modifications, and variations falling within the broad scope of the present application. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A variable-stiffness shock absorber characterized by, The utility model relates to a shell, a ball, a drive assembly, a damping assembly and an adjusting assembly, the ball is contained in the shell, the drive assembly includes an input and a first transmission part, the input is assembled in the shell and is used for receiving the vibration force generated by the external machine, the first transmission part is rotatably installed in the shell and is configured to be able to rotate under the drive of the input to drive the ball to rotate, the damping assembly includes a second transmission part and an output, the second transmission part is rotatably installed in the shell and is configured to be able to rotate under the drive of the ball, and the output is assembled in the second transmission part and is used for outputting the vibration force, wherein the rotation axis of the first transmission part and the rotation axis of the second transmission part intersect, the adjusting assembly is installed in the shell and is configured to be used for adjusting the rotation axis of the ball, the adjusting assembly includes an adjusting part and a driver, the driver is fixedly installed in the shell, the adjusting part is fixedly installed in the output end of the driver and can rotate under the action of the driver. The adjusting part includes a first adjusting unit and at most two second adjusting units, the first adjusting unit is fixedly installed in the output end of the driver and can rotate under the drive of the driver, and the at most two second adjusting units are respectively assembled in the two ends of the first adjusting unit and can rotate under the drive of the first adjusting unit, the first adjusting unit includes a first rotating shaft and at most two first bevel gears, the first rotating shaft is fixedly installed in the driver and can rotate under the drive of the driver, and the at most two first bevel gears are respectively fixedly installed in the two ends of the first rotating shaft, the second adjusting unit includes a second rotating shaft, a second bevel gear and a first roller, the second bevel gear is fixedly installed in the second rotating shaft and is engaged with the first bevel gear, the first roller is hinged to one end of the second rotating shaft close to the ball and can rotate under the drive of the ball, wherein the rotation axis of the second rotating shaft is different from the rotation axis of the first transmission part and the rotation axis of the second transmission part, the input includes an input gear and an input rack, the input gear is fixedly installed in the first transmission part, and the input rack is engaged with the input gear, the first transmission part includes a first transmission shaft and a second roller, the first transmission shaft is fixedly installed in the input gear and can rotate under the drive of the input gear, and the second roller is fixedly installed in one end of the first transmission shaft close to the ball and can rotate with the first transmission shaft. The utility model relates to a shell, a ball, a drive assembly, a damping assembly and an adjusting assembly, the ball is contained in the shell, the drive assembly includes an input and a first transmission part, the input is assembled in the shell and is used for receiving the vibration force generated by the external machine, the first transmission part is rotatably installed in the shell and is configured to be able to rotate under the drive of the input to drive the ball to rotate, the damping assembly includes a second transmission part and an output, the second transmission part is rotatably installed in the shell and is configured to be able to rotate under the drive of the ball, and the output is assembled in the second transmission part and is used for outputting the vibration force, wherein the rotation axis of the first transmission part and the rotation axis of the second transmission part intersect, the adjusting assembly is installed in the shell and is configured to be used for adjusting the rotation axis of the ball, the adjusting assembly includes an adjusting part and a driver, the driver is fixedly installed in the shell, the adjusting part is fixedly installed in the output end of the driver and can rotate under the action of the driver. The adjusting part includes a first adjusting unit and at most two second adjusting units, the first adjusting unit is fixedly installed in the output end of the driver and can rotate under the drive of the driver, and the at most two second adjusting units are respectively assembled in the two ends of the first adjusting unit and can rotate under the drive of the first adjusting unit, the first adjusting unit includes a first rotating shaft and at most two first bevel gears, the first rotating shaft is fixedly installed in the driver and can rotate under the drive of the driver, and the at most two first bevel gears are respectively fixedly installed in the two ends of the first rotating shaft, the second adjusting unit includes a second rotating shaft, a second bevel gear and a first roller, the second bevel gear is fixedly installed in the second rotating shaft and is engaged with the first bevel gear, the first roller is hinged to one end of the second rotating shaft close to the ball and can rotate under the drive of the ball, wherein the rotation axis of the second rotating shaft is different from the rotation axis of the first transmission part and the rotation axis of the second transmission part, the input includes an input gear and an input rack, the input gear is fixedly installed in the first transmission part, and the input rack is engaged with the input gear, the first transmission part includes a first transmission shaft and a second roller, the first transmission shaft is fixedly installed in the input gear and can rotate under the drive of the input gear, and the second roller is fixedly installed in one end of the first transmission shaft close to the ball and can rotate with the first transmission shaft. ​ ​ ​ 2. The variable stiffness shock absorber of claim 1, wherein, ​ 3. The variable stiffness shock absorber of claim 2, wherein, ​ 4. The variable stiffness shock absorber of claim 3, wherein ​ 5. The variable stiffness shock absorber of claim 4, wherein, ​ 6. The variable stiffness shock absorber of claim 1, wherein ​ 7. The variable stiffness shock absorber of claim 6 wherein, The second transmission member comprises a second transmission shaft and a third roller, the third roller is fixedly installed on one end of the second transmission shaft close to the ball and can rotate under the driving of the ball; the output member comprises an output gear, an output rack and an elastic structure, the output gear is fixedly installed on the second transmission shaft and can rotate with the second transmission shaft, the output rack is engaged with the output gear, and the elastic structure is abutted between the output rack and the shell.

8. The variable stiffness shock absorber of claim 7, wherein The driving assembly further comprises a third fixing seat fixedly installed on the shell, and the first transmission shaft is rotatably arranged in the third fixing seat; the damping assembly further comprises a fourth fixing seat fixedly installed on the shell, and the second transmission shaft is rotatably arranged in the fourth fixing seat.

9. A method of controlling a variable-stiffness damper as defined in claim 1, wherein At least comprising the following steps: detecting the vibration frequency of the target to be damped; feeding back the vibration frequency to the controller; the controller controls the output end of the driver to rotate to a specified angle according to the vibration frequency.

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