CN107662222B - Variable-rigidity flexible joint based on single power source - Google Patents
Variable-rigidity flexible joint based on single power source Download PDFInfo
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- CN107662222B CN107662222B CN201711153126.2A CN201711153126A CN107662222B CN 107662222 B CN107662222 B CN 107662222B CN 201711153126 A CN201711153126 A CN 201711153126A CN 107662222 B CN107662222 B CN 107662222B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J17/00—Joints
- B25J17/02—Wrist joints
- B25J17/0258—Two-dimensional joints
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
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Abstract
The invention relates to a variable stiffness flexible joint based on a single power source, wherein a joint driving end comprises a joint support, a speed reducer support, an interlocking clutch structure, a harmonic speed reducer and a joint driving motor provided with an encoder; the joint support is a U-shaped structural component, the harmonic reducer is connected with the left end of the joint support through the reducer support, and the output end of the joint driving motor is connected with the rigidity adjusting mechanism through an interlocking clutch structure; the speed reducer bracket is a hollow cylindrical shell, one end of the speed reducer bracket is provided with a mounting hole for connecting a harmonic speed reducer, the other end of the speed reducer bracket is provided with a threaded hole for connecting the left end of the joint bracket, and the speed reducer bracket is also provided with a shaft shoulder; the interlock clutch structure is located within the cavity of the retarder bracket. The joint adopts a single motor to realize joint driving and rigidity adjustment, has compact structure, high integration level, high positioning precision and large-scale continuous linear accurate rigidity adjustment, and has various rigidity adjustment modes.
Description
Technical Field
The invention relates to the technical field of robots, in particular to a variable-rigidity flexible joint based on a single power source.
Background
With the high-speed development of modern industrial technology, the application range of robots is rapidly expanded, the human-computer cooperation is increasingly close, and the safety problem of the robots is increasingly outstanding along with the continuous deep human-computer interaction degree. At present, the robot generally adopts a rigid joint with the outstanding characteristics of simple structure, compact volume, convenient control, accurate positioning and timely response, and the joint rigidity is difficult to dynamically adjust according to the change of external environment and self load so as to meet the safety requirement of man-machine cooperation. Meanwhile, the special robot typically represented by the bionic robot is rapidly developed, and high requirements are also put on the active/passive flexibility of the robot joint. Therefore, flexible joints with variable stiffness characteristics have become a hotspot in the field of robotic research.
Aiming at the flexible joint with variable rigidity, intensive research work of a system is carried out at home and abroad, a plurality of typical joints are developed, for example, a patent document of 'a flexible joint rigidity-changing mechanism (CN 106695870A)' relates to a flexible joint rigidity-changing mechanism, the positions of two roller groups are regulated by using a rigidity regulating motor to change the compression amount of two springs circumferentially arranged on the joint so as to realize effective regulation of the rigidity of the joint, and the two motors are respectively used for joint driving and rigidity regulation due to the arrangement of the joint, so that the structure control is too complex, the cost is relatively high, and meanwhile, the linear accurate regulation of the rigidity of the joint is difficult to realize under the influence of a rigidity regulating principle of a lever and a circumferential spring arrangement form; the patent literature (CN 104985608A) discloses a flexible joint with adjustable rigidity, which is provided with two inclined curved surface discs connected by a spring, and the flexibility of the joint is generated by rolling between the two inclined curved surface discs by a roller which synchronously moves along with the output end of the joint; the patent literature "robot flexible joint with continuously adjustable rigidity (CN 106142132A)" discloses a robot flexible joint with continuously adjustable rigidity, the precompression amount of a floating spring arranged between a spring support frame and a connecting rod pull-down sleeve is adjusted through a rigidity adjusting motor, so that the large-scale continuous adjustment of the rigidity of the joint is realized, but the joint is also provided with two motors respectively used for joint driving and rigidity adjustment, the structural control is more complicated, and meanwhile, the joint positioning precision and the rigidity adjusting precision are relatively lower due to the lack of a corresponding position detecting system.
In summary, although the existing flexible joint can preliminarily realize effective adjustment of joint rigidity, the joint is generally provided with two motors for joint driving and rigidity adjustment respectively, and the two motors have the defects of complex structure control, low positioning precision, single rigidity adjustment mode, difficult linear and accurate rigidity adjustment, limited adjustment range and the like. Therefore, it is needed to develop a variable stiffness flexible joint which adopts a single motor to realize joint driving and stiffness adjustment, has compact structure, high integration level, high positioning precision, large continuous linear and accurate stiffness adjustment, multiple stiffness adjustment modes and easy control.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to solve the technical problems that: the variable stiffness flexible joint has the advantages of realizing joint driving and stiffness adjustment by adopting a single motor, along with compact structure, high integration level, high positioning precision, large-scale continuous linear accurate adjustment of stiffness, multiple stiffness adjustment modes and easy control.
The technical scheme adopted by the invention for solving the technical problems is as follows: the design of the variable stiffness flexible joint based on the single power source comprises a joint driving end, a stiffness adjusting mechanism and a joint output end; the joint output end is connected with the joint load, and two ends of the rigidity adjusting mechanism are respectively and rigidly connected with the joint driving end and the joint output end; the method is characterized in that:
The joint driving end comprises a joint support, a speed reducer support, an interlocking clutch structure, a harmonic speed reducer and a joint driving motor provided with an encoder; the joint support is a U-shaped structural component, the harmonic reducer is connected with the left end of the joint support through the reducer support, the output end of the joint driving motor is connected with the rigidity adjusting mechanism through the interlocking clutch structure, the joint driving motor is fixed on the joint support, and the joint driving motor and the harmonic reducer are coaxially arranged; the speed reducer bracket is a hollow cylindrical shell, one end of the speed reducer bracket is provided with a mounting hole for connecting a harmonic speed reducer, the other end of the speed reducer bracket is provided with a threaded hole for connecting the left end of the joint bracket, and the speed reducer bracket is also provided with a shaft shoulder; the interlocking clutch structure is positioned in the cavity of the speed reducer bracket;
the joint output end comprises an output shell, an output disc and an output end encoder; the output shell and the output disc enclose a closed space, a driving end bearing is arranged at the left end of the output shell and the shaft shoulder position of the speed reducer bracket, and the right end face of the output shell is fixedly connected with the output disc in a coaxial way; the center of the output disc is connected with an output end encoder, and an output end bearing is arranged between the output disc and the joint support;
The interlocking clutch structure comprises a motor mounting plate, a spline sliding block, an electromagnet, an output end cover, a shaft sleeve, a sliding block and a clutch spring; the motor mounting plate is a cylindrical shell with a spline groove arranged on the inner surface, the left end of the motor mounting plate is connected with the joint driving motor and the joint support, and the motor mounting plate and the joint driving motor are coaxially fixed on the joint support through screw connection; the spline slider is a hollow disc part, the outer surface of the spline slider is provided with a spline matched with a spline groove on the inner surface of the motor mounting disc, and radial positioning and axial movement between the spline slider and the motor mounting disc are realized through spline connection; the right side face of the spline sliding block is embedded with an electromagnet, and the center of the spline sliding block is provided with a groove; the output end cover is a cylindrical shell and is positioned in the cavity of the speed reducer bracket, one end of the output end cover is connected with the input end of the harmonic speed reducer, the end face of the other end of the output end cover is magnetized and matched with the electromagnet, and the surface treatment for increasing the friction coefficient is carried out on the inner surface and the outer surface of one end of the output end cover which is magnetized;
the sliding block is of a hollow cylinder structure, comprises a large cylinder part and a small cylinder part, the small cylinder part is provided with a shaft shoulder matched with a central groove of the spline sliding block, the left end face and the right end face of the large cylinder part are subjected to surface treatment for increasing friction coefficient, the left end face of the large cylinder part of the sliding block is connected with the inner surface of the output end cover subjected to surface treatment for increasing friction coefficient through friction driving, the center of the sliding block is provided with a spline groove matched with the spline on the outer surface of the sliding block, synchronous rotation and axial movement between the sliding block and the sliding block are realized through spline connection, a clutch spring is arranged between the sliding block and the sliding block, the two ends of the clutch spring are respectively in full contact with the right end face of the sliding block and the inner end face of the sliding block, and the sliding block is pressed on the left end inner surface of the output end cover;
The rigidity adjusting mechanism comprises a fixed shell, an adjusting disc retainer ring, a guide post, a bull eye wheel, a rigidity adjusting spring, a trapezoidal screw, a screw bearing, a screw nut and a screw end part;
the trapezoidal screw rod comprises an optical axis part and a threaded part, one end of the optical axis part is coaxially arranged in the harmonic speed reducer through a screw rod bearing, the other end of the optical axis part penetrates through the center of the harmonic speed reducer and penetrates through a center hole of the fixed shell and a center hole of the adjusting shell, and the optical axis part is coaxially arranged in the fixed shell through the other screw rod bearing; the end part of the screw rod is a disc part and is coaxially and fixedly arranged at the end part of the optical axis of the trapezoidal screw rod, the left end surface of the end part of the screw rod is subjected to surface treatment for increasing the friction coefficient, and the driving connection between the sliding block and the end part of the screw rod is realized through friction;
the fixed shell is a cylindrical shell, a spline groove is formed in the inner surface of the fixed shell, the left end of the fixed shell is coaxially connected with the output end of the harmonic reducer, and synchronous rotation of the fixed shell along with the output end of the harmonic reducer is achieved; the adjusting shell is a cylindrical shell, a spline matched with a spline groove on the inner surface of the fixed shell is arranged on the outer surface of the adjusting shell, synchronous rotation and axial movement between the adjusting shell and the fixed shell are realized through spline connection, the spline groove is arranged on the inner surface of the adjusting shell, a screw nut connecting threaded hole is formed in one end of the adjusting shell, a mounting flange of the screw nut is fixedly connected with the screw nut connecting threaded hole on the inner surface of the adjusting shell through a screw, and the screw nut is matched with a threaded part of a trapezoidal screw to form a threaded transmission mechanism; the adjusting shell takes the screw nut connecting threaded holes as the center, three guide post connecting threaded holes are uniformly arranged along the circumferential direction, the guide posts are inserted into the guide post connecting threaded holes and fixed with the adjusting shell, the axes of the guide posts are parallel to the axis of the adjusting shell, and the right ends of the guide posts are provided with bull's eye grooves;
The adjusting disc is a disc-type part, a spline matched with a spline groove on the inner surface of the adjusting shell is arranged on the outer surface of the adjusting disc, the adjusting disc is embedded in the adjusting shell, an adjusting disc check ring is fixedly arranged on the right end face of the adjusting shell, synchronous rotation and axial movement between the adjusting disc and the adjusting shell are realized through spline connection, and three bull-eye wheel connecting threaded holes are uniformly formed in the adjusting disc along the circumferential direction; the lower part of the bullseye wheel consists of an optical axis and a mounting stud, the optical axis is inserted into a bullseye groove of the guide post, the mounting stud is matched with a bullseye wheel connecting threaded hole of the adjusting disc, and the guide post and the bullseye wheel form a moving pair; each guide post is nested and provided with a rigidity adjusting spring, and two ends of the rigidity adjusting spring are respectively and completely contacted with the end face of the adjusting shell and the end face of the adjusting disc; the upper roller of the bullseye wheel and the output disc form a space cam mechanism.
Compared with the prior art, the rigidity-adjustable flexible joint has the beneficial effects that:
(1) The flexible joint with variable rigidity adopts an interlocking clutch structure, and the joint driving and rigidity adjustment can be realized by adopting only one joint driving motor: the flexible joint is provided with the interlocking clutch structure at the joint driving motor end, and the interlocking clutch structure realizes the switching of the joint driving motor between the joint driving mode and the rigidity adjusting mode by adjusting the axial position of the sliding block under the cooperation of the magnetic force between the electromagnet and the output end cover and the elastic force of the clutch spring;
(2) The rigidity of the flexible joint with variable rigidity is greatly and continuously adjustable, and the adjustment of the rigidity of the joint from complete rigidity to complete flexibility can be realized: the rigidity adjusting mechanism and the output disc of the flexible joint form a space cam mechanism, wherein the output disc with a curved surface groove can be regarded as a cam, a bullnose wheel in the rigidity adjusting mechanism can be regarded as a roller, a fixed shell in the rigidity adjusting mechanism can be regarded as a frame, the rigidity adjusting mechanism is driven by a joint driving motor to change the precompression amount of a rigidity adjusting spring by adjusting the distance between the adjusting shell and the adjusting disc through a screw transmission mechanism, so that the positive pressure between the bullnose wheel serving as the roller and the output disc serving as the cam is changed, and the curved surface groove meeting the requirement of joint rigidity adjustment is matched, so that the joint rigidity is greatly and continuously adjusted from complete rigidity to complete flexibility;
(3) The flexible joint with variable rigidity can realize high-precision linear adjustment of the rigidity of the joint: the flexible joint realizes high-precision control of the compression amount of the stiffness adjusting spring by matching with the joint driving motor with the encoder through the thread transmission mechanism with self-locking performance and composed of the trapezoidal screw rod and the screw rod nut so as to adjust the joint stiffness, meanwhile, the compression amount of the stiffness adjusting spring is in linear relation with the elasticity, the curvature change of the curved surface groove of the output disc meets the linear adjustment requirement of the joint stiffness, and the high-precision linear adjustment of the joint stiffness can be realized;
(4) The variable-rigidity flexible joint facilitates accurate control of joint rigidity: according to the invention, the optical axis of the bullnose wheel which is vertically arranged with the adjusting disc in the flexible joint is nested in the guide post groove which is parallel to the axis of the adjusting shell, the stiffness adjusting spring is nested on the guide post, and the two ends of the stiffness adjusting spring are respectively and completely contacted with the end face of the adjusting shell and the end face of the adjusting disc, so that the stiffness adjusting spring is vertical to the end face of the adjusting shell and the end face of the adjusting disc, and is matched with the spline connection among the fixed shell, the adjusting shell and the adjusting disc to ensure that the stiffness adjusting spring is always in positive compression, so that the compression amount of the stiffness adjusting spring and the elasticity are in linear relation, and meanwhile, the curvature change of the curved surface groove of the output disc meets the linear adjustment requirement of joint stiffness, the position of a contact point can be accurately determined, the calculation error can be conveniently reduced, and the position of the bullnose wheel in the curved surface groove of the output disc can be accurately calculated by adopting a double-encoder structure, thereby being convenient for the establishment of a high-precision stiffness adjusting model, and further being convenient for the accurate control of joint stiffness;
(5) The flexible joint with variable rigidity adopts a double-encoder structure, so that the positioning precision of the joint is greatly improved: the joint driving end of the flexible joint is provided with the joint driving motor with the encoder, so that high-precision position control of the fixed shell and the screw nut can be realized, meanwhile, an output end encoder is arranged between the joint support and the output disc and used for detecting the relative rotation angle between the joint output disc and the joint support, and the positioning precision of the joint is greatly improved by adopting the structure form of double encoders, so that the detection of the relative positions of the joint driving end and the joint output end can be realized and the feedback position information of the output end encoder is utilized to form a full-closed-loop position servo system;
(6) The variable-rigidity flexible joint has various rigidity adjustment modes, and can meet the requirements of active/passive rigidity adjustment of the joint: the flexible joint can drive the trapezoidal screw rod to rotate through the joint driving motor under the cooperation of the interlocking clutch structure, so that the distance between the adjusting shell and the adjusting disc is adjusted under the action of the screw rod nut to change the precompression amount of the stiffness adjusting spring, thereby changing the positive pressure between the bull-eye wheel and the curved surface groove of the output disc to realize the adjustment of the joint stiffness, and the stiffness adjusting mode is particularly suitable for the condition that the joint stiffness is required to be passively adjusted under the condition that the flexible joint output end has no load; in addition, the flexible joint can control the joint driving end to output torque by adjusting the current of the joint driving end joint driving motor, control the joint rigidity by adjusting the torque, and also can detect the relative position between the joint driving end and the joint output end by using the output end encoder, and change the position of the bullnose wheel in the curved groove of the output disc by adjusting the relative position between the joint driving end and the joint output end, so that the joint rigidity is changed, and the two rigidity adjusting modes are relatively suitable for the condition that the joint rigidity is required to be actively adjusted under the action of load at the joint output end.
(7) The flexible joint with variable rigidity has the advantages of simple and compact structure, high integration level, large movement range and strong generality: the joint support and the output disc of the flexible joint are provided with the universal connecting holes for connecting the base, the load and other joints, so that the universality is high, all parts of the joint are connected by the spline and are nested, the whole structure of the joint is compact, the movement range between the joint driving end and the joint output end is large, and the whole integration level of the joint is high.
Drawings
FIG. 1 is a schematic cross-sectional view of the general structure of one embodiment of a variable stiffness flexible joint of the present invention;
FIG. 2 is a schematic general structural view of an embodiment of a variable stiffness flexible joint of the present invention;
FIG. 3 is a schematic illustration of an interlocking clutch configuration of one embodiment of a variable stiffness flexible joint of the present invention;
FIG. 4 is a schematic view of a stiffness adjustment mechanism of an embodiment of a variable stiffness flexible joint of the present invention;
FIG. 5 is a schematic perspective view of an articulating bracket according to one embodiment of the present invention having a variable stiffness flexible joint;
FIG. 6 is a schematic view of a reducer support structure of an embodiment of a variable stiffness flexible joint of the present invention;
FIG. 7 is a schematic view of a slider structure of an embodiment of a variable stiffness flexible joint of the present invention;
FIG. 8 is a schematic view of a fixed housing structure of an embodiment of a variable stiffness flexible joint of the present invention;
FIG. 9 is a schematic illustration of an adjustable housing configuration of one embodiment of a variable stiffness flexible joint of the present invention;
FIG. 10 is a schematic illustration of a bullseye wheel construction of an embodiment of a variable stiffness flexible joint of the present invention;
in the figure, 1 joint bracket, 2 reducer bracket, 3 motor mounting disc, 4 spline slide block, 5 electromagnet, 6 output end cover, 7 shaft sleeve, 8 slide block, 9 clutch spring, 10 harmonic reducer, 11 joint driving motor, 12 fixed shell, 13 adjusting shell, 14 adjusting disc, 15 adjusting disc retainer ring, 16 guide post, 17 bull wheel, 18 rigidity adjusting spring, 19 trapezoidal screw, 20 screw bearing, 21 screw nut, 22 screw end, 23 output shell, 24 output disc, 25 driving end bearing, 26 output end bearing, 27 output end encoder, 101 bracket connection through hole, 102 motor mounting disc through hole, 103 bearing hole, 104 connecting hole, 201 mounting hole, 202 screw hole, 203 shaft shoulder, 801 large cylindrical part, 802 small cylindrical part, 1301 screw nut connection screw hole, 1302 guide post connection screw hole, 1701 mounting stud 1702 optical axis, 2401 cylindrical boss, 2402 curved surface groove, 2403L-shaped structure.
Detailed Description
The present invention will be described in detail with reference to the following examples and the accompanying drawings. The embodiment is a specific implementation based on the technical scheme of the invention, and detailed implementation modes and processes are given. The scope of the claims of the present application is not limited to the following description of the embodiments.
The invention discloses a flexible joint with variable rigidity based on a single power source (called flexible joint for short, see figures 1-10), which comprises a joint driving end, a rigidity adjusting mechanism and a joint output end; the joint output end is connected with the joint load, and two ends of the rigidity adjusting mechanism are respectively and rigidly connected with the joint driving end and the joint output end; the method is characterized in that:
the joint driving end comprises a joint bracket 1, a speed reducer bracket 2, an interlocking clutch structure, a harmonic speed reducer 10 and a joint driving motor 11 provided with an encoder; the joint support 1 is a U-shaped structural component, the harmonic reducer 10 is connected with the left end of the joint support 1 through the reducer support 2, the output end of the joint driving motor 11 is connected with the rigidity adjusting mechanism through an interlocking clutch structure, the joint driving motor 11 is fixed on the joint support 1, and the joint driving motor and the harmonic reducer 10 are coaxially installed; the speed reducer bracket 2 is a hollow cylindrical shell, one end of the speed reducer bracket 2 is provided with a mounting hole 201 for connecting the harmonic speed reducer 10, the other end is provided with a threaded hole 202 matched with a bracket connecting through hole at the left end of the joint bracket 1, and the speed reducer bracket 2 is also provided with a shaft shoulder 203; the interlocking clutch structure is positioned in the cavity of the speed reducer bracket;
The joint output comprises an output housing 23, an output disc 24 and an output encoder 27; the output shell 23 and the output disc enclose a closed space, a driving end bearing 25 is arranged at the position of the left end of the output shell 23 and the shaft shoulder of the speed reducer bracket 2, and the right end face of the output shell 23 is fixedly connected with the output disc 24 in a coaxial manner; the center of the output disc 24 is connected with an output end encoder 27, and an output end bearing 26 is arranged between the output disc and the joint support;
the interlocking clutch structure comprises a motor mounting disc 3, a spline sliding block 4, an electromagnet 5, an output end cover 6, a shaft sleeve 7, a sliding block 8 and a clutch spring 9; the motor mounting plate 3 is a cylindrical shell with a spline groove arranged on the inner surface, the left end of the motor mounting plate 3 is connected with the joint driving motor 11 and the joint bracket 1, and the motor mounting plate 3 and the joint driving motor 11 are coaxially fixed on the joint bracket 1 through screw connection; the spline slider 4 is a hollow disc part, a spline matched with a spline groove on the inner surface of the motor mounting disc 3 is arranged on the outer surface of the spline slider 4, and radial positioning and axial movement between the spline slider 4 and the motor mounting disc 3 are realized through spline connection; the electromagnet 5 is embedded on the right side surface of the spline slider 4, and a groove is arranged in the center of the spline slider; the output end cover 6 is a cylindrical shell and is positioned in the cavity of the speed reducer bracket, one end of the output end cover 6 is connected with the input end of the harmonic speed reducer 10, the end face of the other end is magnetized and matched with the electromagnet, and the surface treatment for increasing the friction coefficient is carried out on the inner surface and the outer surface of one end of the output end cover 6 which is magnetized;
The shaft sleeve 7 is coaxially sleeved on an output shaft of the joint driving motor 11, a spline is arranged on the outer surface of the shaft sleeve 7, the sliding block 8 is of a hollow cylinder structure and comprises a large cylinder part and a small cylinder part, the small cylinder part is provided with a shaft shoulder matched with a central groove of the spline sliding block 4, the left end face and the right end face of the large cylinder part are subjected to surface treatment for increasing friction coefficient, the left end face of the large cylinder part of the sliding block is connected with the inner surface of the output end cover subjected to surface treatment for increasing friction coefficient through friction driving, the center of the sliding block 8 is provided with a spline groove matched with the spline on the outer surface of the shaft sleeve 7, synchronous rotation and axial movement between the sliding block 8 and the shaft sleeve 7 are realized through spline connection, a clutch spring 9 is arranged between the sliding block 8 and the shaft sleeve, and two ends of the clutch spring 9 are respectively in full contact with the right end face of the shaft sleeve 7 and the inner end face of the sliding block 8, and the sliding block 8 is pressed on the left end inner surface of the output end cover 6;
the rigidity adjusting mechanism comprises a fixed shell 12, an adjusting shell 13, an adjusting disc 14, an adjusting disc retainer ring 15, a guide post 16, a bullnose wheel 17, a rigidity adjusting spring 18, a trapezoidal screw 19, a screw bearing 20, a screw nut 21 and a screw end 22;
the trapezoidal screw 19 comprises an optical axis part and a threaded part, one end of the optical axis part is coaxially arranged in the harmonic reducer through a screw bearing 20, the other end of the optical axis part penetrates through the center of the harmonic reducer 10 and penetrates through the center holes of the fixed shell and the adjusting shell, and the optical axis part is coaxially arranged in the fixed shell through the other screw bearing 20; the screw end 22 is a disc-like part and is coaxially and fixedly arranged at the optical axis end of the trapezoidal screw 19, the left end face of the screw end 22 is subjected to surface treatment for increasing the friction coefficient, and the driving connection between the slide block 8 and the screw end 22 is realized through friction;
The fixed shell 12 is a cylindrical shell, a spline groove is formed in the inner surface of the fixed shell 12, the left end of the fixed shell 12 is coaxially connected with the output end of the harmonic reducer 10, and synchronous rotation of the fixed shell 12 along with the output end of the harmonic reducer 10 is achieved; the adjusting shell 13 is a cylindrical shell, a spline matched with a spline groove on the inner surface of the fixed shell 12 is arranged on the outer surface of the adjusting shell 13, synchronous rotation and axial movement between the adjusting shell 13 and the fixed shell 12 are realized through spline connection, the spline groove is arranged on the inner surface of the adjusting shell 13, a screw nut connecting threaded hole 1301 is arranged at one end of the adjusting shell 13, a mounting flange of the screw nut 21 is fixedly connected with the inner surface of the adjusting shell through a screw, and the screw nut is matched with a threaded part of the trapezoidal screw 19 to form a threaded transmission mechanism; the adjusting shell 13 takes the screw nut connecting threaded holes as the center, three guide post connecting threaded holes 1302 are uniformly arranged along the circumferential direction, the guide posts are inserted into the guide post connecting threaded holes and fixed with the adjusting shell, the axes of the guide posts are parallel to the axis of the adjusting shell, and the right ends of the guide posts are provided with bullseye grooves;
the adjusting disk 14 is a disk-like part, a spline matched with a spline groove on the inner surface of the adjusting shell 13 is arranged on the outer surface of the adjusting disk 14, the adjusting disk 14 is embedded in the adjusting shell, an adjusting disk retainer ring 15 is fixedly arranged on the right end surface of the adjusting shell, synchronous rotation and axial movement between the adjusting disk 14 and the adjusting shell 13 are realized through spline connection, and three bull-eye wheel connecting threaded holes are uniformly formed in the adjusting disk 14 along the circumferential direction; the lower part of the bullseye wheel 17 is composed of an optical axis 1702 and a mounting stud 1701, the optical axis is inserted into a bullseye groove of the guide post, the mounting stud is matched with a bullseye wheel connecting threaded hole of the adjusting disc, and the guide post and the bullseye wheel form a moving pair; a rigidity adjusting spring 18 is nested and arranged on each guide post, and two ends of the rigidity adjusting spring 18 are respectively and completely contacted with the end face of the adjusting shell 13 and the end face of the adjusting disc 14; the upper rollers of the bullseye and output disc 24 form a space cam mechanism.
The working principle and the working process of the flexible joint with variable rigidity are as follows: the joint driving motor is used for providing torque required by joint driving and rigidity adjustment, when an electromagnet arranged on a spline sliding block is powered off, the joint driving motor works in a joint driving mode, the sliding block is separated from the end part of a screw rod and is tightly pressed on an output end cover under the action of elasticity of a clutch spring, under the action of friction connection of the sliding block and the output end cover, the output torque of the joint driving motor is sequentially transmitted to a harmonic reducer through a shaft sleeve, the sliding block and the output end cover, the output end of the harmonic reducer drives a fixed shell to synchronously rotate, the fixed shell sequentially transmits the torque to an adjusting shell and an adjusting disc through spline connection, and the adjusting disc drives a load connected with the output disc to rotate through a space cam mechanism formed by a bull eye wheel and the output disc, so that joint driving is realized. For the adjustment of the joint rigidity, various rigidity adjustment modes can be adopted to meet the requirement of active and passive adjustment of the joint rigidity: when an electromagnet arranged on a spline slider is electrified, the joint driving motor works in a rigidity adjusting mode, the spline slider is in friction connection with an output end cover under the action of magnetic field force, the spline slider is limited by the spline connection between the spline slider and a motor mounting disc fixed on a joint bracket, the input end of a harmonic reducer is static so as to avoid the influence of joint motion on rigidity adjustment, meanwhile, the spline slider overcomes the elasticity of a clutch spring to push the slider to axially move under the action of the magnetic field force of the electromagnet and the output end cover so as to realize the separation of the slider and the output end cover and the friction connection of the slider and the end part of a screw rod, the output torque of the joint driving motor is sequentially transmitted to a trapezoidal screw rod through a shaft sleeve, the slider and the end part of the screw rod, and the distance between an adjusting shell and the adjusting disc is adjusted through a thread transmission mechanism formed by the trapezoidal screw rod and a screw rod nut so as to change the precompression amount of the rigidity adjusting spring, thereby changing the positive pressure between a bullnose wheel and a curved surface groove of the output disc and realizing the adjustment of the joint rigidity; secondly, adjusting the current of a joint driving end joint driving motor to control the joint driving end to output torque, and controlling the joint rigidity through torque adjustment; thirdly, detecting the relative position between the joint driving end and the joint output end by using an output end encoder, and changing the position of the bullseye wheel in the curved groove of the output disc by adjusting the relative position between the joint driving end and the joint output end, thereby realizing the adjustment of joint rigidity.
According to the invention, the flexible joint adopts an interlocking clutch structure, joint driving and rigidity adjustment can be realized by adopting only one joint driving motor, the interlocking clutch structure realizes the switching between joint driving and rigidity adjustment modes by adjusting the axial position of the sliding block under the cooperation of magnetic force between the electromagnet and the output end cover and the elasticity of the clutch spring, when the electromagnet is powered off, the sliding block is separated from the end part of the lead screw under the elasticity of the clutch spring and is tightly pressed on the output end cover, under the friction connection effect of the sliding block and the output end cover, the output torque of the joint driving motor is sequentially transmitted to a harmonic reducer through the shaft sleeve, the sliding block and the output end cover for driving the joint to move, when the electromagnet is powered on, the spline sliding block overcomes the friction connection of the sliding block and the end cover under the magnetic force of the electromagnet and the output end cover to realize the separation of the sliding block and the output end cover and the friction connection of the sliding block and the end part of the lead screw under the elasticity of the clutch spring, and the output torque of the joint driving motor is sequentially transmitted to the rigidity adjustment mechanism through the shaft sleeve, and the sliding block and the end cover under the elasticity of the clutch spring, and the spline sliding block and the output end cover are simultaneously limited by the friction connection between the spline sliding block and the motor mounting plate of the motor fixed on the joint bracket under the effect of the magnetic force, so that the spline sliding block and the spline end is not influenced on the rigidity adjustment of the joint driving motor, and the joint driving motor is not influenced on the rigidity adjustment mode.
The rigidity adjusting mechanism and the output disc form a space cam mechanism, wherein the output disc with a curved surface groove can be regarded as a cam, the bullnose wheel in the rigidity adjusting mechanism can be regarded as a roller, the fixed shell in the rigidity adjusting mechanism can be regarded as a frame, the rigidity adjusting mechanism is driven by the joint driving motor to change the precompaction amount of the rigidity adjusting spring by adjusting the distance between the adjusting shell and the adjusting disc through the screw transmission mechanism, so that the positive pressure between the bullnose wheel serving as the roller and the output disc serving as the cam is changed, and the groove curved surface meeting the joint rigidity adjusting requirement is matched, so that the joint rigidity is greatly and continuously adjusted from complete rigidity to complete flexibility.
The joint driving end is provided with the joint driving motor with the encoder, so that high-precision position control of the fixed shell and the screw nut can be realized, meanwhile, the output end encoder is arranged between the joint support and the output disc and is used for detecting the relative rotation angle between the joint output disc and the joint support, and the positioning precision of the joint is greatly improved by adopting the structure of the double encoders, so that the detection of the relative position between the joint driving end and the joint output end can be realized and the feedback position information of the output end encoder is utilized to form a full-closed-loop position servo system.
The joint realizes high-precision control of the compression amount of the stiffness adjusting spring by matching the threaded transmission mechanism with self-locking performance and composed of the trapezoidal screw rod and the screw rod nut with the joint driving motor with the encoder so as to adjust the joint stiffness, meanwhile, the compression amount of the stiffness adjusting spring is in linear relation with the elasticity, the curvature change of the curved surface of the groove of the output disc meets the linear adjustment requirement of the joint stiffness, and the high-precision linear adjustment of the joint stiffness can be realized.
According to the invention, the optical axis of the bullnose wheel vertically installed on the regulating disc is nested in the bullnose groove of the guide column which is installed in parallel with the axis of the regulating shell, the rigidity regulating spring is nested on the guide column, two ends of the rigidity regulating spring are respectively and completely contacted with the end face of the regulating shell and the end face of the regulating disc, so that the rigidity regulating spring is vertical to the end face of the regulating shell and the end face of the regulating disc, the movement direction of the regulating shell and the stress direction of the rigidity regulating spring are always kept on the same straight line by matching with the spline connection among the fixed shell, the regulating shell and the regulating disc, the rigidity regulating spring is always kept in positive compression, the problem that an included angle is generated between the stress direction and the compression direction due to bending in the compression process of the rigidity regulating spring is avoided, the calculation error caused by force decomposition is reduced, the rigidity regulating spring compression amount and elasticity are enabled to be in a linear relation, meanwhile, the curved surface curvature change of the curved surface of the output disc meets the linear regulation requirement of joint rigidity, the position of the curved surface of the bullnose wheel and the curved surface groove point contact of the output disc can be accurately determined, the calculation of the position of the curved surface of the output disc can be accurately calculated by adopting a double encoder structure, the position of the bullnose wheel in the curved surface is conveniently established, and the high-precision rigidity regulating model is conveniently, and the accurate control of the joint rigidity is conveniently.
Example 1
The variable-rigidity flexible joint based on the single power source comprises a joint driving end, a rigidity adjusting mechanism and a joint output end; the joint driving end is used for providing torque required by joint driving and rigidity adjustment; the joint output end is connected with a joint load and used for driving the load to move; the two ends of the rigidity adjusting mechanism are respectively and rigidly connected with the joint driving end and the joint output end, and are used for adjusting the connection rigidity between the joint driving end and the joint output end, transmitting the output torque of the joint driving end to the joint output end, and realizing the rigidity adjustment and flexible output of the joint.
The joint driving end comprises a joint bracket 1, a speed reducer bracket 2, an interlocking clutch structure, a harmonic speed reducer 10 and a joint driving motor 11; the joint support 1 (see fig. 5) is a U-shaped structural component, a support connecting through hole 101 for connecting the speed reducer support 2 and a motor mounting plate through hole 102 for connecting the motor mounting plate 3 are formed in the left end of the joint support 1, the speed reducer support 2 and the motor mounting plate 3 are coaxially fixed on the joint support 1 through screw connection, the right end of the speed reducer support 2 is connected with the harmonic reducer 10, the joint driving motor 11 and the motor mounting plate are coaxially fixed, and the harmonic reducer 10 and the joint driving motor 11 and the joint support 1 are coaxially fixed through the speed reducer support and the motor mounting plate; the right end of the joint support 1 is provided with an encoder connecting through hole for connecting the output end encoder 27, the output end encoder 27 is rigidly connected with the joint support 1 through a screw, and the center of the right end of the joint support 1 is provided with a bearing hole 103 matched with the outer ring of the output end bearing 26 for positioning and mounting the output end bearing 26; the plane of the lower end of the joint bracket 1 is provided with a plurality of connecting holes 104 for realizing the fixed connection between the flexible joint and the base or other joints; the speed reducer bracket 2 (see fig. 6) is a hollow cylindrical shell, one end of the speed reducer bracket 2 is provided with a mounting hole 201 for connecting the harmonic speed reducer 10, the other end is provided with a threaded hole 202 matched with a bracket connecting through hole at the left end of the joint bracket 1, the coaxial fixed connection of the harmonic speed reducer 10 and the joint bracket 1 is realized through the speed reducer bracket 2 by screw connection, and meanwhile, the speed reducer bracket 2 is also provided with a shaft shoulder 203 for positioning and mounting a driving end bearing 25;
The interlocking clutch structure comprises a motor mounting disc 3, a spline sliding block 4, an electromagnet 5, an output end cover 6, a shaft sleeve 7, a sliding block 8 and a clutch spring 9; the motor mounting plate 3 is a cylindrical shell with a spline groove arranged on the inner surface, and the left end of the motor mounting plate 3 is provided with two connecting flanges which are respectively matched with the mounting flange of the joint driving motor 11 and the motor mounting plate connecting through hole 102 of the joint bracket 1 and are used for coaxially fixing the motor mounting plate 3 and the joint driving motor 11 to the joint bracket 1 through screw connection; the spline slider 4 is a hollow disc part, a spline matched with a spline groove on the inner surface of the motor mounting disc 3 is arranged on the outer surface of the spline slider 4, radial positioning and axial movement between the spline slider 4 and the motor mounting disc 3 are realized through spline connection, an electromagnet 5 is embedded on the side surface of the spline slider 4, the contact and separation of the spline slider 4 and the output end cover 6 are controlled through current on-off of the electromagnet 5 so as to realize the switching of the joint driving motor 11 between joint driving and rigidity adjusting modes, a groove matched with the shaft shoulder of the slider 8 is arranged in the center of the spline slider 4, and the spline slider 8 is pushed to axially move against the elastic force of a clutch spring 9 under the action of attractive force of the electromagnet 5 and the output end cover 6, so that the separation of the slider 8 and the output end cover 6 is realized; the output end cover 6 is a cylindrical shell, the right end of the output end cover 6 is provided with an end cover connecting hole for connecting the input end of the harmonic reducer 10, the output end cover 6 is fixedly arranged at the input end of the harmonic reducer 10 through screw connection, the left end of the output end cover 6 is provided with a central hole, the inner surface and the outer surface of the left end of the output end cover 6 are subjected to surface treatment to increase friction coefficient, the output end cover 6 and the slide block 8 are in driving connection through friction, the left end of the output end cover 6 can be attracted with an electromagnet 5 arranged on the spline slide block 4 through magnetization treatment, and the slide block 8 is driven to axially move along the shaft sleeve 7, so that the slide block 8 and the screw end 22 are in driving connection through friction; the shaft sleeve 7 is a hollow shaft part, is coaxially and fixedly arranged on an output shaft of the joint driving motor 11, and is provided with a spline on the outer surface; the sliding block 8 is of a hollow cylinder structure and comprises a large cylinder part 801 and a small cylinder part 802, the left end of the small cylinder part is provided with a shaft shoulder matched with the central groove of the spline sliding block 4 and is used for pushing the spline sliding block 4 to axially move under the action of the elasticity of the clutch spring 9 so as to realize the contact between the sliding block 8 and the output end cover 6, and the right end of the small cylinder part is connected with the large cylinder part; the left end face and the right end face of the large cylindrical part of the sliding block 8 are subjected to surface treatment to increase friction coefficients, so that the sliding block 8 is respectively in driving connection with the screw end 22 and the output end cover 6 through friction, a spline groove matched with a spline on the outer surface of the shaft sleeve 7 is formed in the center of the sliding block 8, and synchronous rotation and axial movement between the sliding block 8 and the shaft sleeve 7 are realized through spline connection; the clutch spring 9 is nested and arranged on the shaft sleeve 7, and two ends of the clutch spring 9 are respectively and completely contacted with the right end face of the shaft sleeve 7 and the inner end face of the sliding block 8, and are used for pressing the sliding block 8 on the inner surface of the left end of the output end cover 6, so that the driving connection between the sliding block 8 and the output end cover 6 is realized through friction;
The interlocking clutch structure is used for switching the driving connection between the joint driving motor 11 and the harmonic reducer 10 and the rigidity adjusting mechanism, so that the joint driving motor 11 is switched between joint driving and rigidity adjusting modes, when the electromagnet 5 embedded in the spline slider 4 is powered off, the slider 8 is pressed on the output end cover 6 under the action of the elasticity of the clutch spring 9, under the action of the friction connection between the slider 8 and the output end cover 6, the output torque of the joint driving motor 11 is sequentially transmitted to the harmonic reducer 10 through the shaft sleeve 7, the slider 8 and the output end cover 6 for driving the joint to move, the joint driving motor 11 works in the joint driving mode, when the electromagnet 5 is powered on, the spline slider 4 overcomes the action of the magnetic force of the electromagnet 5 and the output end cover 6 to push the slider 8 to axially move so as to realize the separation of the slider 8 and the output end cover 6 and the friction connection of the slider 8 and the lead screw end 22, the output torque of the joint driving motor 11 is sequentially transmitted to the rigidity adjusting mechanism through the shaft sleeve 7, the slider 8 and the lead screw end 22 for adjusting the rigidity of the joint, and meanwhile, the spline slider 4 and the output end cover 6 are in the action of the friction connection under the action of the magnetic force, and the limitation of the magnetic force are limited by the slider 4 and the spline end cover 6 and the output end cover 6 are fixed on the motor 3, and the joint driving motor is fixed on the joint end, and the spline motor, and the joint driving motor is not influenced by the rigidity of the spline driving motor, and the joint driving motor is not limited to move in the rigidity, and the joint driving mode; the harmonic speed reducer 10 is coaxially and fixedly arranged on the speed reducer bracket 2, wherein the input end of the harmonic speed reducer 10 is fixedly connected with the output end cover 6 of the interlocking clutch structure, and the output end of the harmonic speed reducer 10 is rigidly connected with the fixed shell 12 of the rigidity adjusting mechanism; the joint driving motor 11 provided with the encoder is fixedly arranged on the motor mounting plate 3, and an output shaft of the joint driving motor is fixedly connected with the shaft sleeve 7 of the interlocking clutch structure and is used for realizing high-precision joint driving and rigidity adjustment under the switching of the interlocking clutch structure.
The rigidity adjusting mechanism mainly comprises a fixed shell 12, an adjusting shell 13, an adjusting disc 14, an adjusting disc retainer ring 15, a guide post 16, a bullseye wheel 17, a rigidity adjusting spring 18, a trapezoidal screw 19, a screw bearing 20, a screw nut 21 and a screw end 22; the fixed shell 12 is a cylindrical shell, a spline groove is formed in the inner surface of the fixed shell 12, a connecting flange matched with the flange at the output end of the harmonic reducer 10 is arranged at the left end of the fixed shell 12, and the fixed shell 12 is coaxially fixed to the harmonic reducer 10 through screw connection, so that synchronous rotation of the fixed shell 12 along with the output end of the harmonic reducer 10 is realized; the adjusting housing 13 is a cylindrical housing, the outer surface of the adjusting housing 13 is provided with a spline matched with a spline groove on the inner surface of the fixed housing 12, the spline groove is used for realizing synchronous rotation and axial movement between the adjusting housing 13 and the fixed housing 12 through spline connection, the inner surface of the adjusting housing 13 is provided with the spline groove, the left end of the adjusting housing 13 is provided with a screw nut connecting threaded hole 1301 matched with a screw nut 21 mounting flange, the screw nut 21 mounting flange and the screw nut connecting threaded hole are fixed on the inner surface of the adjusting housing through screw connection, the left end of the adjusting housing 13 is circumferentially and uniformly provided with three guide post connecting threads 1302 matched with the guide post 16, and the fixed mounting of the adjusting housing 13 and the guide post 16 is realized through screw connection; the right end of the adjusting shell 13 is provided with a connecting flange matched with the mounting flange of the adjusting disc check ring 15, and the connecting flange is used for fixedly mounting the adjusting disc check ring 15; the adjusting disc 14 is a disc-like part, the outer surface of the adjusting disc 14 is provided with a spline matched with a spline groove on the inner surface of the adjusting shell 13, the spline is used for realizing synchronous rotation and axial movement between the adjusting disc 14 and the adjusting shell 13 through spline connection, and the adjusting disc 14 is uniformly provided with three bullseye wheel connecting threaded holes matched with the bullseye wheel 17 mounting studs 1701 along the circumferential direction, and the spline is used for realizing fixed connection between the adjusting disc 14 and the bullseye wheel 17 through threaded connection; the adjusting disc retainer ring 15 is fixedly arranged on the adjusting shell 13 and used for limiting the position of the adjusting disc 14 and preventing the adjusting disc 14 from sliding out of the adjusting shell 13; the guide post 16 is a shaft part, one end of the guide post 16 is provided with threads, the guide post 16 is fixedly arranged in the adjusting shell 13 through threaded connection, the axis of the guide post 16 is parallel to the axis of the adjusting shell 13, and the other end of the guide post 16 is provided with a bullseye groove with a specific depth matched with the optical axis of the bullseye wheel 17; the supporting part of the bullseye wheel 17 is provided with a section of mounting stud 1701 and a section of optical axis 1702, the bullseye wheel 17 is vertically fixed on the adjusting disk 14 through the mounting stud 1701, so that the optical axis 1702 is nested in the bullseye groove of the guide post 16, and a moving pair is formed with the guide post 16; the rigidity adjusting spring 18 is nested on the guide post 16, and two ends of the rigidity adjusting spring 18 are respectively and completely contacted with the end face of the adjusting shell 13 and the end face of the adjusting disc 14, so that the rigidity adjustment and the flexible output of the joint are realized by adjusting the precompression amount of the rigidity adjusting spring 18; one end of the trapezoidal screw 19 is provided with an optical axis, the trapezoidal screw 19 is coaxially and fixedly arranged on the fixed shell 12 through two screw bearings 20 arranged on the optical axis, the other end of the trapezoidal screw 19 and a screw nut 21 coaxially arranged on the adjusting shell 13 form a threaded transmission mechanism, and the threaded transmission mechanism is used for adjusting the distance between the adjusting shell 13 and the adjusting disc 14 so as to change the precompression amount of the stiffness adjusting spring 18 to realize joint stiffness adjustment; the screw end 22 is a disc-like part and is coaxially and fixedly arranged at the optical axis end of the trapezoidal screw 19, the left end surface of the screw end 22 is subjected to surface treatment to increase the friction coefficient, and the screw end 22 is used for realizing the driving connection of the slide block 8 and the screw end 22 through friction and transmitting the output torque of the joint driving motor 11 to the rigidity adjusting mechanism for adjusting the joint rigidity;
The torque of the joint driving motor 11 can drive the trapezoidal screw 19 to rotate through the screw end 22 under the switching of an interlocking clutch structure, and then the distance between the regulating housing 13 and the regulating disk 14 is regulated under the action of the screw nut 21 so as to change the precompression amount of the stiffness regulating spring 18, thereby changing the positive pressure between the bullnose wheel 17 and the curved surface groove of the output disk 24 to realize the regulation of joint stiffness, meanwhile, the axial movement distance between the fixed housing 12 and the regulating housing 13 in the stiffness regulating mechanism, the stroke of the threaded transmission mechanism formed by the trapezoidal screw 19 and the screw nut 21 and the stroke formed by the guide post 16 and the bullnose wheel 17 simultaneously meet the requirements that the bullnose wheel 17 and the output disk 24 can be completely separated from each other under the driving of the joint driving motor 11, the guide post 16 and the bullnose wheel 17 and the output disk 24 can be completely rigidly contacted, the flexible joint is completely flexible when the optical axis end surface of the bullnose wheel 17 and the bottom end of the guide post 16 are completely contacted with the curved surface groove of the output disk 24, the flexible joint is completely rigid when the bullnose wheel 17 is pressed on the output disk 24 under the elastic force of the stiffness regulating spring 18, in addition, the gap between the continuous flexible joint 17 and the continuous joint can be completely rigid when the bullnose wheel 17 is pressed on the output disk 24 under the action of the stiffness regulating spring 18 can be completely contacted with the output disk, and the mechanical joint can be completely rigid, and the gap can be changed, and the gap can be completely flexible, when the mechanical joint can be completely separated from the output disk 14 is completely, and the mechanical joint can be completely flexible, and the joint can be completely flexible.
The joint output end mainly comprises an output shell 23, an output disc 24, a driving end bearing 25, an output end bearing 26 and an output end encoder 27; the output shell 23 is a cylindrical shell, the left end of the output shell 23 is provided with a bearing hole matched with the outer ring of a driving end bearing 25 arranged on the shaft shoulder of the speed reducer bracket 2, the right end face of the output shell 23 is provided with an output disc connecting threaded hole matched with an output disc connecting flange, and the output shell 23 and the output disc 24 are coaxially and fixedly connected through screw connection; the output disc 24 is a disc-like part and is fixedly connected with the output shell 23, a cylindrical boss 2401 is arranged in the center of the right end of the output disc 24, a shaft hole matched with the output shaft of the output end encoder 27 is arranged in the center of the cylindrical boss 2401, the outer cylindrical surface of the cylindrical boss 2401 is matched with the inner ring of an output end bearing 26 arranged in a bearing hole of the right end of the joint support 1, three curved surface grooves 2402 which are symmetrical in center are arranged on the left end surface of the output disc 24, the curvature change of the curved surface of the grooves meets the linear regulation requirement of joint rigidity, the output disc 24 is provided with an L-shaped structure 2403, and a plurality of connecting through holes are arranged on the plane of the lower end of the L-shaped structure and are used for realizing the fixed connection of a flexible joint and a load or other joints; the inner ring of the driving end bearing 25 is matched with the shaft shoulder of the speed reducer bracket 2, and the outer ring is matched with the bearing hole of the output shell 23; the inner ring of the output end bearing 26 is matched with a cylindrical boss of the output disc 24, the outer ring is matched with a bearing hole at the right end of the joint support 1, and the driving end bearing 25 and the output end bearing 26 are matched to realize effective fixed support of the joint output end; the output end encoder 27 is fixedly connected to the joint support 1, and an output shaft of the output end encoder 27 is connected with a shaft hole of a cylindrical boss of the output disc 24, so that synchronous rotation of the output shaft of the output end encoder 27 and the output disc 24 is realized, and the output end encoder 27 is used for detecting relative rotation angles between the output disc 24 and the joint support 1.
In this embodiment, the thickness of the joint support and the thickness of the output disc are both 12mm, and the thicknesses of the fixed housing, the adjusting housing and the adjusting disc are all 10mm, and the encoder according to this embodiment adopts an absolute value encoder.
It should be noted that the invention is described as "front and rear; left and right; the words of up, down, etc. are words of relative significance for clarity of description, and generally, the end where the joint driving motor is located is left, the end where the output end encoder is located is right, and the words of other orientations are used as references.
The invention is applicable to the prior art where it is not described.
Claims (2)
1. A variable stiffness flexible joint based on a single power source comprises a joint driving end, a stiffness adjusting mechanism and a joint output end; the joint output end is connected with the joint load, and two ends of the rigidity adjusting mechanism are respectively and rigidly connected with the joint driving end and the joint output end; the method is characterized in that:
the joint driving end comprises a joint support, a speed reducer support, an interlocking clutch structure, a harmonic speed reducer and a joint driving motor provided with an encoder; the joint support is a U-shaped structural component, the harmonic reducer is connected with the left end of the joint support through the reducer support, the output end of the joint driving motor is connected with the rigidity adjusting mechanism through the interlocking clutch structure, the joint driving motor is fixed on the joint support, and the joint driving motor and the harmonic reducer are coaxially arranged; the speed reducer bracket is a hollow cylindrical shell, one end of the speed reducer bracket is provided with a mounting hole for connecting a harmonic speed reducer, the other end of the speed reducer bracket is provided with a threaded hole for connecting the left end of the joint bracket, and the speed reducer bracket is also provided with a shaft shoulder; the interlocking clutch structure is positioned in the cavity of the speed reducer bracket;
The joint output end comprises an output shell, an output disc and an output end encoder; the output shell and the output disc enclose a closed space, a driving end bearing is arranged at the left end of the output shell and the shaft shoulder position of the speed reducer bracket, and the right end face of the output shell is fixedly connected with the output disc in a coaxial way; the center of the output disc is connected with an output end encoder, and an output end bearing is arranged between the output disc and the joint support;
the interlocking clutch structure comprises a motor mounting plate, a spline sliding block, an electromagnet, an output end cover, a shaft sleeve, a sliding block and a clutch spring; the motor mounting plate is a cylindrical shell with a spline groove arranged on the inner surface, the left end of the motor mounting plate is connected with the joint driving motor and the joint support, and the motor mounting plate and the joint driving motor are coaxially fixed on the joint support through screw connection; the spline slider is a hollow disc part, the outer surface of the spline slider is provided with a spline matched with a spline groove on the inner surface of the motor mounting disc, and radial positioning and axial movement between the spline slider and the motor mounting disc are realized through spline connection; the right side face of the spline sliding block is embedded with an electromagnet, and the center of the spline sliding block is provided with a groove; the output end cover is a cylindrical shell and is positioned in the cavity of the speed reducer bracket, one end of the output end cover is connected with the input end of the harmonic speed reducer, the end face of the other end of the output end cover is magnetized and matched with the electromagnet, and the surface treatment for increasing the friction coefficient is carried out on the inner surface and the outer surface of one end of the output end cover which is magnetized;
The sliding block is of a hollow cylinder structure, comprises a large cylinder part and a small cylinder part, the small cylinder part is provided with a shaft shoulder matched with a central groove of the spline sliding block, the left end face and the right end face of the large cylinder part are subjected to surface treatment for increasing friction coefficient, the left end face of the large cylinder part of the sliding block is connected with the inner surface of the output end cover subjected to surface treatment for increasing friction coefficient through friction driving, the center of the sliding block is provided with a spline groove matched with the spline on the outer surface of the sliding block, synchronous rotation and axial movement between the sliding block and the sliding block are realized through spline connection, a clutch spring is arranged between the sliding block and the sliding block, the two ends of the clutch spring are respectively in full contact with the right end face of the sliding block and the inner end face of the sliding block, and the sliding block is pressed on the left end inner surface of the output end cover;
the rigidity adjusting mechanism comprises a fixed shell, an adjusting disc retainer ring, a guide post, a bull eye wheel, a rigidity adjusting spring, a trapezoidal screw, a screw bearing, a screw nut and a screw end part;
the trapezoidal screw rod comprises an optical axis part and a threaded part, one end of the optical axis part is coaxially arranged in the harmonic speed reducer through a screw rod bearing, the other end of the optical axis part penetrates through the center of the harmonic speed reducer and penetrates through a center hole of the fixed shell and a center hole of the adjusting shell, and the optical axis part is coaxially arranged in the fixed shell through the other screw rod bearing; the end part of the screw rod is a disc part and is coaxially and fixedly arranged at the end part of the optical axis of the trapezoidal screw rod, the left end surface of the end part of the screw rod is subjected to surface treatment for increasing the friction coefficient, and the driving connection between the sliding block and the end part of the screw rod is realized through friction;
The fixed shell is a cylindrical shell, a spline groove is formed in the inner surface of the fixed shell, the left end of the fixed shell is coaxially connected with the output end of the harmonic reducer, and synchronous rotation of the fixed shell along with the output end of the harmonic reducer is achieved; the adjusting shell is a cylindrical shell, a spline matched with a spline groove on the inner surface of the fixed shell is arranged on the outer surface of the adjusting shell, synchronous rotation and axial movement between the adjusting shell and the fixed shell are realized through spline connection, the spline groove is arranged on the inner surface of the adjusting shell, a screw nut connecting threaded hole is formed in one end of the adjusting shell, a mounting flange of the screw nut is fixedly connected with the screw nut connecting threaded hole on the inner surface of the adjusting shell through a screw, and the screw nut is matched with a threaded part of a trapezoidal screw to form a threaded transmission mechanism; the adjusting shell takes the screw nut connecting threaded holes as the center, three guide post connecting threaded holes are uniformly arranged along the circumferential direction, the guide posts are inserted into the guide post connecting threaded holes and fixed with the adjusting shell, the axes of the guide posts are parallel to the axis of the adjusting shell, and the right ends of the guide posts are provided with bull's eye grooves;
the adjusting disc is a disc-type part, a spline matched with a spline groove on the inner surface of the adjusting shell is arranged on the outer surface of the adjusting disc, the adjusting disc is embedded in the adjusting shell, an adjusting disc check ring is fixedly arranged on the right end face of the adjusting shell, synchronous rotation and axial movement between the adjusting disc and the adjusting shell are realized through spline connection, and three bull-eye wheel connecting threaded holes are uniformly formed in the adjusting disc along the circumferential direction; the lower part of the bullseye wheel consists of an optical axis and a mounting stud, the optical axis is inserted into a bullseye groove of the guide post, the mounting stud is matched with a bullseye wheel connecting threaded hole of the adjusting disc, and the guide post and the bullseye wheel form a moving pair; each guide post is nested and provided with a rigidity adjusting spring, and two ends of the rigidity adjusting spring are respectively and completely contacted with the end face of the adjusting shell and the end face of the adjusting disc; the upper roller of the bullseye wheel and the output disc form a space cam mechanism.
2. The flexible joint with variable rigidity based on a single power source according to claim 1, wherein the output disc is a disc-like part, a cylindrical boss is arranged in the center of the right end of the output disc, the cylindrical boss is connected with an output end encoder, three curved surface grooves which are symmetrical in center are formed in the left end face of the output disc, each bullnose wheel can be in contact with the curved surface of the curved surface groove under the action of the elastic force of a rigidity adjusting spring to transmit power, the curvature change of the curved surface groove meets the linear adjustment requirement of the joint rigidity, the output disc is provided with an L-shaped structure, and a plurality of connecting through holes for realizing the fixed connection of the flexible joint and a load or other joints are formed in the end face of the L-shaped structure.
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| CN201711153126.2A CN107662222B (en) | 2017-11-20 | 2017-11-20 | Variable-rigidity flexible joint based on single power source |
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| CN201711153126.2A CN107662222B (en) | 2017-11-20 | 2017-11-20 | Variable-rigidity flexible joint based on single power source |
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| CN107662222A CN107662222A (en) | 2018-02-06 |
| CN107662222B true CN107662222B (en) | 2023-05-23 |
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| DE102018008378B4 (en) * | 2018-10-22 | 2020-07-23 | Technische Universität Chemnitz | Elastic joint |
| CN110450161B (en) * | 2019-08-15 | 2020-09-29 | 四川大学 | Flexible mechanical arm device capable of actively and passively adjusting rigidity |
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