CN116394295A - Robot joint with output end encoder and control method - Google Patents

Abstract

The invention discloses a robot joint with an output end encoder and a control method, wherein the robot joint is formed by integrating a synchronous motor, a planetary reduction gearbox and the output end encoder arranged in a shell; meanwhile, the motor end encoder magnet is fixedly connected to the outer rotor retainer, the motor controller can be used for measuring the angular displacement of the outer rotor retainer, the output end encoder magnet in the output end encoder is fixedly connected to the encoder output gear, the angular displacement of the output flange is measured through the output end encoder circuit board, the relative position of the output flange relative to the zero position of the output flange is obtained when the synchronous motor starts to start, even if the synchronous motor is restarted after power failure, the relative position of the output flange is not lost, the power failure is further realized, the zero position is kept, the motor controller of the on-board encoder is not required to be continuously supplied with power, the motor is not required to be manually swung back to the zero position after the power failure is restarted each time, the module size is greatly reduced, and the operation difficulty is reduced.

Description

Robot joint with output end encoder and control method

Technical Field

The invention belongs to the field of robot joint design and control, and particularly relates to a robot joint with an output end encoder and a control method.

Background

With the development of robot technology in recent years, robots have been widely used in various fields and gradually tend to be miniaturized and civilian. The motor with the reduction gearbox is used as an actuator for realizing various functions of the robot, is an important component of the robot, and is an important research direction in the field of robots at present. Aiming at the small civil robot, the design scheme of the semi-direct-drive joint of the planetary reduction gearbox with the low-speed high-torque permanent magnet synchronous motor is applied to various foot robots and partial mechanical arms because of the advantages of low cost, light weight, convenience in miniaturization, relatively high output torque and the like.

In view of the accuracy of the angular displacement encoding, for motors with reduction boxes, the motor controller typically measures the angular displacement of the outer rotor cage with an encoder. Compared with the method for measuring the angular displacement of the output flange by using the encoder, the scheme has the advantage of high measurement accuracy, but has the defect that the zero point of the output flange cannot be stored. Zero position of the robot joint output shaft is critical to motor control, and if zero position cannot be permanently recorded, the motor can be rotated to a dangerous range, so that accidents are caused. To solve this problem, the conventional solution is to externally power the motor controller, or manually reset the motor to near zero before restarting each power outage. However, these two approaches have significant drawbacks: the scheme of the external power supply leads the structural volume of the robot joint to be enlarged, the weight to be heavier, and the robot joint is not beneficial to being arranged on a robot; the manual reset complicates the operation before restarting the robot after power failure each time, and seriously influences the efficiency of robot debugging.

Disclosure of Invention

The invention aims to provide a robot joint with an output end encoder, which is formed by integrating a synchronous motor, a planetary reduction gearbox and the output end encoder arranged in a shell, so that the compactness of the whole structure is realized; meanwhile, the motor end encoder magnet is fixedly connected to the outer rotor retainer, the motor controller can be used for measuring the angular displacement of the outer rotor retainer, the output end encoder is connected with the planetary reduction gearbox, the output end encoder magnet in the output end encoder is fixedly connected to the encoder output gear, the output end encoder circuit board is used for measuring the angular displacement of the output flange, so that the zero position is kept in a power-off state, an external power supply and manual reset are not needed, and the production cost is low.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

a robotic joint with an output encoder, comprising:

the synchronous motor comprises a shell, a rotor assembly, a stator and a motor controller, wherein the stator is fixedly connected in an inner cavity of the shell, the rotor assembly is rotationally connected in the inner cavity of the shell, the motor controller is fixedly connected in the shell, the rotor assembly comprises a motor end encoder magnet, and the motor end encoder magnet is used for providing position feedback of the rotor assembly to the motor controller;

The planetary reduction gearbox comprises an output mechanism and a reduction mechanism, wherein the reduction mechanism comprises a fixed assembly which keeps the relative position with the shell unchanged and a rotating assembly connected with the rotor assembly, the output mechanism is connected with the rotating assembly, and the rotor assembly drives the rotating assembly and the output mechanism to rotate;

the output end encoder comprises an output end encoder circuit board, an output end encoder magnet, an encoder output gear and an encoder input gear; the encoder input gear is connected with the output mechanism, the output mechanism drives the encoder input gear to rotate, the encoder input gear is used for driving the encoder output gear to rotate, the output end encoder magnet is arranged on the encoder output gear, and the output end encoder circuit board is used for receiving position feedback of the output mechanism provided by the output end encoder magnet.

Preferably, the synchronous motor is an outer rotor synchronous motor, the rotor assembly further comprises an outer rotor retainer and an outer rotor steel ring, the outer rotor steel ring is fixedly connected to the outer rotor retainer, the motor end encoder magnet is mounted at one end of the outer rotor retainer, which faces the motor controller, so that the motor controller can sense the motor end encoder magnet, position feedback of the outer rotor retainer provided by the motor end encoder magnet is received, and the outer rotor retainer is rotationally connected with the casing through a rotor bearing.

Preferably, a fixing part is arranged at one end of the casing in an extending manner into the inner cavity, a rotor bearing is fixed at an inner ring of the fixing part, one end of the outer rotor retainer, which faces the motor controller, is fixed in the inner ring of the rotor bearing, so that the outer rotor retainer can be in rotary connection with the casing, the stator is fixed on an outer ring of the fixing part, so that the relative position between the stator and the casing is kept unchanged, the stator is firmly installed on the casing, an installation part is arranged at one end of the outer rotor retainer, which faces the motor controller, the installation part is provided with a cavity, a motor end encoder magnet is arranged in the cavity, and one end of a rotating assembly in the speed reducing mechanism is also inserted in the cavity, so that the rotating assembly is driven to rotate when the outer rotor retainer rotates.

Preferably, the motor controller is fixedly connected to one end of the casing far away from the output end encoder, and the motor controller is fixed to one end of the casing through a circuit board screw. Because the motor end encoder magnet is fixedly connected to the outer rotor retainer, the angular displacement of the outer rotor retainer can be measured through the motor controller. The output end encoder magnet is fixedly connected to the encoder output gear, and the angular displacement of the output flange can be measured through the output end encoder circuit board.

Preferably, the synchronous motor further comprises a rear cover, the rear cover is mounted at one end of the machine shell through a rear cover screw, and the motor controller is arranged at the inner side of the rear cover, so that the motor controller is ensured to be sealed in the inner cavity of the machine shell, and the motor controller is protected.

Preferably, the output mechanism comprises an end cover, an output flange and an output planet carrier which are sequentially arranged, the end cover is fixedly connected with one end of the shell, which is far away from the motor controller, the output flange is rotationally connected with the end cover, and the output planet carrier is fixedly connected with the output flange so that the output planet carrier and the output flange rotate together relative to the end cover.

Preferably, an end cover bearing is mounted on the end cover, the end cover bearing is arranged at the middle position of the end cover, the outer ring of the output flange is sleeved in the end cover bearing, so that the output flange is rotationally connected with the end cover, the output planet carrier is mounted on the output flange through screws, and the outer ring of the output planet carrier can be sleeved and fixed in the inner ring of the end cover bearing, so that the stability of the output planet carrier in the rotation process can be ensured.

Preferably, the output encoder circuit board is mounted to the end cap by screws.

Preferably, the fixed assembly of the speed reducing mechanism comprises a fixed ring gear, the fixed ring gear is fixedly connected with the end cover, an end cover bearing gasket is further arranged between the end face of the fixed ring gear and the end cover, and the end cover bearing is pressed through the end cover bearing gasket; the rotating assembly of the speed reducing mechanism comprises a planetary gear set, the planetary gear set is arranged in an inner cavity of the fixed ring gear, and the planetary gear set is respectively connected with the output planet carrier and the outer rotor retainer, so that the outer rotor retainer drives the planetary gear set and the output planet carrier to rotate when rotating, and the planetary gear set is used for controlling the rotating speed ratio of the outer rotor retainer and the output planet carrier, and further controlling the speed reducing ratio of the whole planetary reduction gearbox.

Preferably, the planetary gear set includes a sun gear and a plurality of planetary gears located on the periphery of the sun gear, the sun gear is disposed at the center of the inner cavity of the fixed ring gear, an inner ring of the fixed ring gear is provided with an inner gear ring, the planetary gears are disposed between the inner gear ring and the sun gear, the planetary gears are meshed with an outer ring of the sun gear and the inner gear ring at the same time, and the sun gear is connected with the outer rotor holder, so that the outer rotor holder drives the sun gear to rotate.

Preferably, the output planet carrier is provided with a plurality of gear mounting grooves, and the planet gears are arranged in the gear mounting grooves, so that when the sun gear drives the planet gears to rotate, the planet gears drive the output planet carrier to rotate.

Preferably, a gear mounting column is arranged in the gear mounting groove, the planetary gears are rotatably mounted on the gear mounting column through bearings, each gear mounting groove is correspondingly provided with one planetary gear, the transmission ratio of the sun gear to the planetary gears is changed by adjusting the number of the planetary gears and/or the diameter ratio of the planetary gears to the sun gear, so that the rotation speed ratio of the output planet carrier, the output flange and the outer rotor retainer is adjusted, and the reduction ratio of the whole planetary reduction gearbox is further changed.

Preferably, a plurality of stages of planetary gear sets are arranged, each stage of planetary gear set comprises a sun gear and a planetary gear, each adjacent planetary gear set is connected through a supporting planetary carrier, each stage of planetary gear set corresponds to one supporting planetary carrier, a plurality of gear mounting grooves for mounting the planetary gears are also formed in the supporting planetary carrier, wherein the sun gears in the planetary gear sets close to the outer rotor retainer mounting parts are inserted into cavities of the mounting parts, the supporting planetary carriers assembled by the planetary gear sets close to the output planetary carrier are oppositely arranged, the gear mounting grooves on the two supporting planetary gear sets are correspondingly arranged, the supporting planetary carriers close to the output planetary carrier are of a semi-open structure, and the gear mounting grooves on the output planetary carrier and the gear mounting grooves on the corresponding supporting planetary carriers jointly enclose a mounting area for mounting the planetary gears, so that the planetary gears close to the output planetary carrier can be mounted in the mounting area through mounting shafts, and the planetary gears can be ensured to simultaneously drive the supporting planetary carrier and the output planetary carrier to rotate when rotating. The connection mode of every two adjacent planetary gear sets is as follows: the sun gear of one planetary gear set is connected with the mounting cavity on the supporting planet carrier assembled by the other planetary gear set, so that when one planetary gear set drives the assembled supporting planet carrier to rotate, the sun gear of the other planetary gear set is driven to rotate, the corresponding planetary gears and the supporting planet carrier are driven to rotate by the sun gear, and finally, the rotation of the outer rotor retainer is transmitted to the output planet carrier and the output flange through the multistage planetary gear sets. When the height of the synchronous motor is overlarge, the multistage planetary gear set can be arranged to realize power transmission, so that the problems that the sizes of the sun gear and the planet gear are overlarge and the service life is limited due to the fact that only one group of planetary gear sets is arranged are prevented.

More preferably, a two-stage planetary gear set is provided, the planetary gear set comprises a lower-stage planetary gear set and an upper-stage planetary gear set, the lower-stage planetary gear set is mounted on the lower-stage planetary gear set, the upper-stage planetary gear set is mounted on the upper-stage planetary gear set, the lower-stage planetary gear set is arranged close to the mounting part of the outer rotor retainer, the upper-stage planetary gear set is arranged close to the output planetary gear set, a sun gear in the lower-stage planetary gear set is inserted into a cavity of the mounting part of the outer rotor retainer, the upper-stage planetary gear set and the output planetary gear set are oppositely arranged, gear mounting grooves on the upper-stage planetary gear set and the upper-stage planetary gear set are correspondingly arranged, the upper-stage planetary gear set is in a semi-open structure, and the gear mounting grooves on the output planetary gear set and the upper-stage planetary gear set jointly enclose a mounting area for mounting the planetary gears of the upper-stage planetary gear set. The sun gear in the upper planetary gear set is connected with the mounting cavity on the lower supporting planetary gear set, so that when the sun gear in the lower planetary gear set is driven to rotate by the outer rotor retainer, the sun gear drives the meshed planetary gears of the lower planetary gear set to rotate, when the planetary gears rotate, the lower supporting planetary gear set drives the sun gear in the upper planetary gear set to rotate, and then the sun gear in the upper planetary gear set drives the corresponding planetary gears, the lower supporting planetary gear set and the output planetary gear set to rotate, and finally, the rotation of the outer rotor retainer is transmitted to the output planetary gear set and the output flange through the lower planetary gear set and the upper planetary gear set.

Preferably, the output end encoder further comprises an encoder output gear bearing and an encoder output gear retainer, a bearing cavity for installing the encoder output gear bearing is formed in the encoder output gear retainer, a connecting shaft assembled with the encoder output gear bearing is arranged on the encoder output gear, so that the encoder output gear is rotatably installed on the encoder output gear retainer, the encoder output gear retainer is fixedly connected to the end cover, and preferably, the encoder output gear retainer is fixed to the inner side face of the end cover through screws.

Preferably, the output end encoder further comprises an encoder transmission gear, the encoder input gear is mounted on the outer ring of the output planet carrier or the output flange, so that the encoder input gear rotates together with the output planet carrier or the output flange, the encoder transmission gear is arranged between the encoder input gear and the encoder output gear, two sides of the encoder transmission gear are respectively meshed with the encoder input gear and the encoder output gear, and power of the encoder input gear is transmitted to the encoder output gear through the encoder transmission gear.

When the output flange or the output planet carrier rotates, the output flange, the output planet carrier and the input gear of the encoder rotate synchronously as a whole, the input gear of the encoder drives the transmission gear of the encoder to rotate, and the transmission gear of the encoder drives the output gear of the encoder to rotate; the output encoder circuit board is able to receive one-to-one output flange position feedback provided by the output encoder magnets.

Preferably, the output end encoder further comprises an encoder output gear shaft clamp spring and an encoder wire slot, wherein the encoder output gear shaft clamp spring is arranged in a groove on a connecting shaft of the encoder output gear, and the encoder output gear shaft clamp spring can prevent the encoder output gear from axially moving. The electric wires of the output end encoder circuit board are arranged on the encoder wire slots; the encoder wire chase is fixed in the inboard of casing to the electric wire of protection output encoder circuit board, and this electric wire can connect output encoder circuit board and motor controller, and then realizes the transmission of electric signal to the motor controller of on-board encoder from output encoder circuit board.

Preferably, the motor controller is a motor controller of an on-board encoder, a motor end encoder for measuring the angular displacement of the outer rotor retainer is integrated on the motor controller of the on-board encoder, and an encoder for measuring the angular displacement of the output flange is integrated on the circuit board of the output end encoder.

The second object of the present invention is to provide a method for controlling a robot joint with an output end encoder, comprising the steps of:

s1, recording an electric signal of an outer rotor retainer zero position in a rotor assembly and an electric signal of an output flange zero position in an output mechanism by a motor controller;

s2, when the motor controller is electrified and operated, a motor end encoder on the motor controller converts the absolute position of the outer rotor retainer into an electric signal and sends the electric signal to the motor controller, and the motor controller records the number of turns of the outer rotor retainer according to a single-turn absolute encoding electric signal output by the motor end encoder on the motor end encoder and converts the single-turn absolute encoding electric signal into a multi-turn absolute encoding;

s3, judging whether the motor controller is powered off and restarted, if so, converting the motor end encoder on the motor controller into an electric signal according to the position of the outer rotor retainer, converting the output end encoder into an electric signal according to the position of the output flange, and simultaneously transmitting the electric signal to the motor controller, so that the motor controller obtains current readings of the motor end encoder and the output end encoder; if not, continuing to execute the step S2;

s4, the motor controller calculates the number of turns of the outer rotor retainer according to the reduction ratio of the planetary reduction gearbox and the readings of the motor end encoder and the output end encoder, and further calculates the absolute position of the output flange relative to the zero point of the outer rotor retainer. Through the step, the actual position of the output shaft of the planetary reduction gearbox, namely the actual position of the output flange, can be calculated and obtained.

The beneficial effects are that:

according to the invention, the synchronous motor, the planetary reduction gearbox and the output end encoder arranged in the shell are integrated together to form the robot joint, so that the compactness of the whole structure is realized; the synchronous motor is matched with the planetary reduction gearbox to transmit power to the output flange, a speed reduction effect is achieved, meanwhile, the position of the output flange can be obtained in real time through output end coding, the position of the output flange is converted into an electric signal and is simultaneously transmitted to the motor controller, and the motor controller calculates the number of turns of the outer rotor retainer according to the reduction ratio of the planetary reduction gearbox and the readings of the output end coder and the coder on the motor controller, so that the absolute position of the output flange relative to the zero point of the outer rotor retainer is calculated.

According to the invention, the motor end encoder magnet in the robot joint is fixedly connected to the outer rotor retainer, the motor controller can be used for measuring the angular displacement of the outer rotor retainer, the output end encoder is connected with the planetary reduction gearbox, the output end encoder magnet in the output end encoder is fixedly connected to the encoder output gear, and the output end encoder circuit board is used for measuring the angular displacement of the output flange, so that the robot joint can acquire the relative position of the output flange relative to the zero position of the output flange when the synchronous motor starts to start, even if the synchronous motor is restarted after power failure, the relative position of the output flange can not be lost, and further the power failure is kept, therefore, the motor controller of the on-board encoder is not required to be externally connected with power, the motor is not required to be manually swung back to the zero position after power failure is restarted each time, the module volume is greatly reduced, and the operation difficulty is reduced.

Drawings

FIG. 1 is a diagram illustrating the overall construction of a robot joint according to the present invention;

FIG. 2 is an exploded view of the robot joint of the present invention;

FIG. 3 is a cross-sectional view of a robotic joint of the present invention;

FIG. 4 is a diagram illustrating the internal construction of a robot joint according to the present invention;

FIG. 5 is a block diagram of the assembly of the planetary reduction gearbox and synchronous motor in the robot joint of the present invention;

FIG. 6 is a diagram of a planetary reduction gearbox in a robotic joint of the present invention;

FIG. 7 is a diagram showing the internal structure of a planetary reduction gearbox in the robot joint according to the present invention;

FIG. 8 is a schematic view of a portion of a reduction mechanism of a planetary reduction gearbox in a robotic joint according to the present invention;

fig. 9 is a control flow diagram of a robotic joint with an output encoder according to the present invention.

Reference numerals

1. A synchronous motor; 101. an outer rotor holder; 1011. a mounting part; 102. an outer rotor steel ring; 103. a stator; 104. a motor end encoder magnet; 105. a rotor bearing; 106. a housing screw; 107. a housing; 108. a circuit board screw; 109. a motor controller; 110. a rear cover screw; 111. a rear cover;

2. a planetary reduction gearbox; 201. an output flange; 202. an end cap; 203. an output planet carrier; 204. an end cap bearing; 205. an end cap bearing washer; 206. a speed reducing mechanism; 2061. a fixed ring gear; 2062. a sun gear; 2063. a planetary gear; 2064. a lower support planet carrier; 2065. an upper support planet carrier;

3. An output end encoder; 301. an output encoder circuit board; 302. an output encoder magnet; 303. an encoder output gear; 304. an encoder output gear bearing; 305. the encoder outputs a gear shaft clamp spring; 306. an encoder output gear holder; 307. an encoder drive gear; 308. an encoder input gear; 309. an encoder wire chase;

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will explain the specific embodiments of the present invention with reference to the accompanying drawings. It is evident that the drawings in the following description are only examples of the invention, from which other drawings and other embodiments can be obtained by a person skilled in the art without inventive effort.

The technical scheme of the invention is described in detail in the following by specific embodiments.

Example 1

As shown in fig. 1-3, a robotic joint with an output encoder 3, comprising: a synchronous motor 1, a planetary reduction gearbox 2 and an output end encoder 3;

the synchronous motor 1 comprises a shell 107, a rotor assembly, a stator 103 and a motor controller 109, wherein the stator 103 is fixedly connected in an inner cavity of the shell 107, the rotor assembly is rotatably connected in the inner cavity of the shell 107, the motor controller 109 is fixedly connected in the shell 107, the rotor assembly comprises a motor end encoder magnet 104, and the motor end encoder magnet 104 is used for providing position feedback of the rotor assembly to the motor controller 109;

The planetary reduction gearbox 2 comprises an output mechanism and a reduction mechanism 206, wherein the reduction mechanism 206 comprises a fixed component which keeps the relative position with the shell 107 unchanged and a rotating component which is connected with the rotor component, the output mechanism is connected with the rotating component, and the rotor component drives the rotating component and the output mechanism to rotate;

the output end encoder 3 is arranged in the shell 107, the output end encoder 3 is connected with the output mechanism, and the output end encoder 3 comprises an output end encoder circuit board 301, an output end encoder magnet 302, an encoder output gear 303 and an encoder input gear 308; the encoder input gear 308 is connected with the output mechanism, the output mechanism drives the encoder input gear 308 to rotate, the encoder input gear 308 is used for driving the encoder output gear 303 to rotate, the output end encoder magnet 302 is mounted on the encoder output gear 303, and the output end encoder circuit board 301 is used for receiving position feedback of the output mechanism provided by the output end encoder magnet 302.

The motor controller 109 is a motor controller 109 of an on-board encoder, a motor end encoder for measuring the angular displacement of the outer rotor holder 101 is integrated on the motor controller 109 of the on-board encoder, and an encoder for measuring the angular displacement of the output flange 201 is integrated on the output end encoder circuit board 301.

The synchronous motor is an outer rotor synchronous motor, further, the synchronous motor is an outer rotor permanent magnet synchronous motor, the rotor assembly further comprises an outer rotor retainer 101 and an outer rotor steel ring 102, the outer rotor steel ring 102 is fixedly connected to the outer rotor retainer 101, specifically, the outer rotor steel ring 102 is fixedly connected to the outer ring of the outer rotor retainer 101, the motor end encoder magnet 104 is mounted at one end of the outer rotor retainer 101, which faces to the motor controller 109, so that the motor controller 109 can sense the motor end encoder magnet 104, and accordingly position feedback of the outer rotor retainer 101 provided by the motor end encoder magnet 104 is received, and the outer rotor retainer 101 is rotationally connected with the casing 107 through a rotor bearing 105.

As shown in fig. 3, a fixing portion is disposed at one end of the housing 107 and extends into the inner cavity, a rotor bearing 105 is fixed at an inner ring of the fixing portion, the outer rotor holder 101 is fixed in the inner ring of the rotor bearing 105 toward one end of the motor controller 109, so that the outer rotor holder 101 can be rotationally connected with the housing 107, the stator 103 is fixed on an outer ring of the fixing portion, so that the relative position of the stator 103 and the housing 107 is kept unchanged, the stator 103 is firmly mounted on the housing 107, a mounting portion 1011 is disposed at one end of the outer rotor holder 101 toward the motor controller 109, a cavity is disposed at the mounting portion 1011, the motor end encoder magnet 104 is disposed in the cavity, and one end of a rotating assembly in the speed reducing mechanism 206 is also inserted in the cavity, so that the rotating assembly is driven to rotate when the outer rotor holder 101 rotates.

The motor controller 109 is fixedly connected to one end of the casing 107 far away from the output end encoder 3, and the motor controller 109 is fixed to one end of the casing 107 through a circuit board screw 108. Since the motor end encoder magnet 104 is fixedly attached to the outer rotor holder 101, the angular displacement of the outer rotor holder 101 can be measured by the motor controller 109. The output encoder magnet 302 is fixedly connected to the encoder output gear 303, and the angular displacement of the output flange 201 can be measured by the output encoder circuit board 301.

The output mechanism of the planetary reduction gearbox 2 comprises an end cover 202, an output flange 201 and an output planet carrier 203 which are sequentially arranged, wherein the end cover 202 is fixedly connected with one end, far away from the motor controller 109, of the casing 107 through a casing screw 106, the output flange 201 is rotationally connected with the end cover 202, and the output planet carrier 203 is fixedly connected with the output flange 201 so that the output planet carrier 203 and the output flange 201 rotate together relative to the end cover 202. The output encoder circuit board 301 is mounted on the end cap 202 by screws.

The end cover 202 is provided with an end cover bearing 204, the end cover bearing 204 is arranged in the middle of the end cover 202, the outer ring of the output flange 201 is sleeved in the end cover bearing 204, so that the output flange 201 is rotationally connected with the end cover 202, the output planet carrier 203 is arranged on the output flange 201 through screws, and the outer ring of the output planet carrier 203 can also be sleeved and fixed in the inner ring of the end cover bearing 204, so that the stability of the output planet carrier 203 in the rotation process can be ensured.

As shown in fig. 3 and 6, the fixed assembly of the reduction mechanism 206 includes a fixed ring gear 2061, the fixed ring gear 2061 is fixedly connected with the end cover 202, and an end cover bearing washer 205 is further disposed between the end surface of the fixed ring gear 2061 and the end cover 202, and the end cover bearing 204 is pressed by the end cover bearing washer 205; the rotating assembly of the reduction mechanism 206 includes a set of planetary gears 2063, the set of planetary gears 2063 are installed in the inner cavity of the fixed ring gear 2061, and the set of planetary gears 2063 are respectively connected with the output planetary carrier 203 and the outer rotor carrier 101, so that the set of planetary gears 2063 and the output planetary carrier 203 are driven to rotate when the outer rotor carrier 101 rotates, and the set of planetary gears 2063 is used for controlling the rotation speed ratio of the outer rotor carrier 101 and the output planetary carrier 203, thereby controlling the reduction ratio of the whole planetary reduction gearbox 2.

As shown in fig. 3, the planetary gear 2063 set includes a sun gear 2062 and a plurality of planetary gears 2063 disposed on the outer periphery of the sun gear 2062, the sun gear 2062 is disposed at the center of the inner cavity of the fixed ring gear 2061, an inner ring of the fixed ring gear 2061 is provided with an inner gear ring, the planetary gears 2063 are disposed between the inner gear ring and the sun gear 2062, the planetary gears 2063 are meshed with an outer ring of the sun gear 2062 and the inner gear ring at the same time, and the sun gear 2062 is connected with the outer rotor cage 101 so that the outer rotor cage 101 drives the sun gear 2062 to rotate.

The output planet carrier 203 is provided with a plurality of gear mounting grooves, and the planet gears 2063 are disposed in the gear mounting grooves, so that when the sun gear 2062 drives the planet gears 2063 to rotate, the planet gears 2063 drive the output planet carrier 203 to rotate.

The gear mounting grooves are provided with gear mounting columns, the planetary gears 2063 are rotatably mounted on the gear mounting columns through bearings, each gear mounting groove is correspondingly provided with one planetary gear 2063, the transmission ratio of the sun gear 2062 to the planetary gears 2063 is changed by adjusting the number of the planetary gears 2063 and/or the diameter ratio of the planetary gears 2063 to the sun gear 2062, so that the rotation speed ratio of the output planet carrier 203, the output flange 201 and the outer rotor retainer 101 is adjusted, and the reduction ratio of the whole planetary reduction gearbox 2 is further changed.

In this embodiment, multiple sets of planetary gears 2063 may be provided, each set of planetary gears 2063 includes a sun gear 2062 and a planetary gear 2063, adjacent sets of planetary gears 2063 are all connected by a supporting planetary carrier, each set of planetary gears 2063 corresponds to a supporting planetary carrier, and a plurality of gear mounting grooves for mounting the planetary gears 2063 are also provided on the supporting planetary carrier, wherein the sun gear 2062 in the set of planetary gears 2063 near the mounting portion 1011 of the outer rotor holder 101 is inserted into the cavity of the mounting portion 1011, the supporting planetary carriers assembled by the sets of planetary gears 2063 near the output planetary carrier 203 are oppositely arranged, the gear mounting grooves on the two sets of planetary gears 2063 are correspondingly arranged, the supporting planetary carrier near the output planetary carrier 203 is in a semi-open structure, and the gear mounting grooves on the output planetary carrier 203 and the corresponding supporting planetary carrier jointly enclose a mounting area for mounting the planetary gears 2063, so that the planetary gears 2063 near the output planetary carrier 203 can be mounted in the mounting area through a mounting shaft, and the planetary gears 2063 can be ensured to simultaneously rotate when the output planetary carrier 203 rotates. Every adjacent two planetary gear 2063 sets are connected as follows: the sun gear 2062 of one planetary gear 2063 is connected with the mounting cavity on the supporting planet carrier assembled by the other planetary gear 2063, so that when one planetary gear 2063 drives the assembled supporting planet carrier to rotate, the sun gear 2062 in the other planetary gear 2063 is driven to rotate, and the sun gear 2062 drives the corresponding planetary gear 2063 and the supporting planet carrier to rotate, and finally, the rotation of the outer rotor retainer 101 is transmitted to the output planet carrier 203 and the output flange 201 through the multistage planetary gear 2063. Thus, when the height of the synchronous motor is too large, the multistage planetary gear 2063 set can be arranged to realize power transmission, so that the problems that the sizes of the sun gear 2062 and the planetary gear 2063 are too large and the service life is limited due to the fact that only one planetary gear 2063 set is arranged are prevented.

As shown in fig. 7 and 8, in this embodiment, a two-stage planetary gear 2063 is specifically provided, the planetary gear 2063 includes a lower planetary gear 2063 and an upper planetary gear 2063, the lower planetary gear 2063 is mounted on the lower support planetary carrier 2064, the upper planetary gear 2063 is mounted on the upper support planetary carrier 2065, the lower planetary gear 2063 is disposed near the mounting portion 1011 of the outer rotor holder 101, the upper planetary gear 2063 is disposed near the output planetary carrier 203, the sun gear 2062 of the lower planetary gear 2063 is inserted in the cavity of the mounting portion 1011 of the outer rotor holder 101, the upper support planetary carrier 2065 and the output planetary carrier 203 are disposed opposite to each other, and the gear mounting grooves on the upper support planetary carrier 2065 are also disposed in a semi-open structure, and the gear mounting grooves on the output planetary carrier 203 and the upper support planetary carrier 2065 jointly enclose a mounting area for mounting the planetary gears 2063 of the upper planetary gear 2063. The sun gear 2062 in the upper planetary gear 2063 set is connected with the installation cavity on the lower support planetary gear 2064, so that when the sun gear 2062 in the lower planetary gear 2063 set is driven to rotate, the sun gear 2062 drives the meshed planetary gear 2063 to rotate, when the planetary gear 2063 rotates, the lower support planetary gear 2064 is driven to rotate, and when the lower support planetary gear 2064 rotates, the sun gear 2062 in the upper planetary gear 2063 set is driven to rotate, and then the sun gear 2062 in the upper planetary gear 2063 set drives the corresponding planetary gear 2063, the lower support planetary gear 2064 and the output planetary gear 203 to rotate, and finally, the rotation of the outer rotor retainer 101 is transmitted to the output planetary gear 203 and the output flange 201 through the lower planetary gear 2063 set and the upper planetary gear 2063 set.

As shown in fig. 4 and 5, the output end encoder 3 further includes an encoder output gear bearing 304 and an encoder output gear holder 306, the encoder output gear holder 306 is provided with a bearing cavity for mounting the encoder output gear bearing 304, the encoder output gear 303 is provided with a connecting shaft assembled with the encoder output gear bearing 304, so that the encoder output gear 303 is rotatably mounted on the encoder output gear holder 306, the encoder output gear holder 306 is fixedly connected to the end cover 202, and preferably, the encoder output gear holder 306 is fixed on the inner side surface of the end cover 202 by screws.

The output end encoder 3 further comprises an encoder transmission gear 307, the encoder input gear 308 is mounted on the outer ring of the output planet carrier 203 or the output flange 201, so that the encoder input gear 308 rotates together with the output planet carrier 203 or the output flange 201, the encoder transmission gear 307 is arranged between the encoder input gear 308 and the encoder output gear 303, the encoder transmission gear 307 is rotatably mounted on one end, close to the end cover 202, of the fixed ring gear 2061, two sides of the encoder transmission gear 307 are respectively meshed with the encoder input gear 308 and the encoder output gear 303, and power of the encoder input gear 308 is transmitted to the encoder output gear 303 through the encoder transmission gear 307.

When the output flange 201 or the output planet carrier 203 rotates, the output flange 201, the output planet carrier 203 and the encoder input gear 308 rotate synchronously, the encoder input gear 308 drives the encoder transmission gear 307 to rotate, and the encoder transmission gear 307 drives the encoder output gear 303 to rotate; the output encoder circuit board 301 is able to receive one-to-one output flange 201 position feedback provided by the output encoder magnets 302. When the robot joint is used, the zero position of the output flange 201 is recorded through the output end encoder circuit board 301, the zero position of the outer rotor assembly is recorded through the motor controller 109, specifically, the zero position of the outer rotor retainer 101 is recorded through the motor controller 109, after the power is turned off and restarted, the single-circle absolute position of the output flange 201 is calculated according to the readings of the output end encoder circuit board 301 and the motor controller 109 encoder, and the robot joint is the robot joint described in the embodiment above.

Example 2

The present embodiment only describes differences from the above-described embodiments, and other technical features are the same, in this embodiment, the synchronous motor further includes a rear cover 111, the rear cover 111 is mounted on one end of the housing 107 by a rear cover screw 110, and the motor controller 109 is disposed inside the rear cover 111, so as to ensure that the motor controller 109 is enclosed in the inner cavity of the housing 107, thereby protecting the motor controller 109.

Example 3

The present embodiment only describes the differences from the above embodiment, and other technical features are the same, in this embodiment, the output end encoder 3 further includes an encoder output gear shaft clamp spring 305 and an encoder wire slot 309, where the encoder output gear shaft clamp spring 305 is installed in a groove on a connecting shaft of the encoder output gear 303, and the encoder output gear shaft clamp spring 305 can prevent the encoder output gear 303 from axially moving. The wires of the output encoder circuit board 301 are mounted on the encoder wireway 309; an encoder wireway 309 is secured to the inside of the housing 107 to protect the wires of the output encoder circuit board 301 that may connect the output encoder circuit board 301 to the motor controller 109, thereby enabling the transmission of electrical signals from the output encoder circuit board 301 to the motor controller 109 of the on-board encoder.

Example 4

The embodiment provides a control method of a robot joint with an output end encoder, wherein the robot joint is the robot joint described in the above embodiments 1-3, a motor end encoder is arranged on a motor controller of the on-board encoder in the robot joint, and is used for converting angular displacement of the outer rotor retainer into an electrical signal, and the electrical signal belongs to a single-turn absolute value encoder, and when a measurement structure is set to rotate, the direction in which the number of output pulses of the encoder increases is positive; the output end encoder is used for converting the angular displacement of the output flange into an electric signal, belongs to a single-circle absolute value encoder, and is used for outputting the direction of increasing the pulse number when the measuring structure of the encoder rotates.

As shown in fig. 9, the control method of the robot joint with the output end encoder of the present embodiment includes the following steps:

s1, recording an electric signal of an outer rotor retainer zero position in a rotor assembly and an electric signal of an output flange zero position in an output mechanism by a motor controller;

s2, when the motor controller is electrified and operated, a motor end encoder on the motor controller converts the absolute position of the outer rotor retainer into an electric signal and sends the electric signal to the motor controller, and the motor controller records the number of turns of the outer rotor retainer according to a single-turn absolute encoding electric signal output by the motor end encoder on the motor end encoder and converts the single-turn absolute encoding electric signal into a multi-turn absolute encoding;

s3, judging whether the motor controller is powered off and restarted, if so, converting the motor end encoder on the motor controller into an electric signal according to the position of the outer rotor retainer, converting the output end encoder into an electric signal according to the position of the output flange, and simultaneously transmitting the electric signal to the motor controller, so that the motor controller obtains current readings of the motor end encoder and the output end encoder; if not, continuing to execute the step S2;

s4, the motor controller calculates the number of turns of the outer rotor retainer according to the reduction ratio of the planetary reduction gearbox and the readings of the motor end encoder and the output end encoder, and further calculates the absolute position of the output flange relative to the zero point of the outer rotor retainer. Through the step, the actual position of the output shaft of the planetary reduction gearbox, namely the actual position of the output flange, can be calculated and obtained.

Further, step S5 is further included, according to the angular displacement of the output flange relative to zero forward rotation of the motor controller when the motor controller is powered off and the pulse number output by the output end encoder, the angular displacement of the outer rotor retainer relative to zero forward rotation of the outer rotor retainer is calculated by combining the reduction ratio of the planetary reduction gearbox, and the number of turns of the outer rotor retainer can be calculated in a reverse-push mode.

In the step S2, when the motor controller is electrified and operates, whether the motor controller needs to record zero position or not is also needed to be judged, if yes, the step S3 is executed; if not, judging whether the output flange (the output shaft of the speed reducer) is placed at an expected zero position, if not, manually placing the output shaft of the speed reducer to the expected zero position, and if so, recording the readings of the motor end encoder and the output end encoder through the motor controller, thereby finishing the input of a zero signal.

More specifically, in one embodiment of the present invention, the reduction ratio of the planetary reduction gearbox 2 is 1:9, the number of encoding bits of the motor end encoder and the output end encoder 3 above the motor controller 109 is 14, and the outer rotor holder 101 rotates 1 turn, and the motor end encoder outputs 16384 pulses. The output flange 201 rotates 1 turn, the output end encoder 3 outputs 16384 pulses, the outer rotor holder 101 rotates 9 turns, and the motor end encoder outputs 147456 pulses. Therefore, assuming that the output flange 201 rotates forward by 60 ° with respect to its zero position at the time of power failure, the output end encoder 3 outputs 2731 pulses, and the outer rotor holder 101 rotates forward by 540 ° with respect to its zero position according to the reduction ratio, but since the encoder used is single-turn absolute value encoding, the number of output pulses at the time of the output end encoder is 8192 as in the case where the outer rotor holder 101 rotates forward by 180 ° with respect to its zero position, and further it can be calculated that the outer rotor holder 101 rotates by 1 turn.

Therefore, the robot joint example with the output end encoder 3 adopted by the invention can acquire the relative position of the output flange relative to the zero position of the output flange when the motor starts to start, and even if the motor is restarted after power failure, the relative position of the output flange 201 can not be lost, so that external power supply is not required to be continuously supplied to the motor controller 109 of the on-board encoder, and the motor is not required to be manually swung back to the zero position after the motor is restarted after power failure each time, thereby greatly reducing the module volume and the operation difficulty.

The embodiments of the present invention are described in detail above. The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the core concepts of the invention. It should be noted that it will be apparent to those skilled in the art that the present invention may be modified and adapted without departing from the principles of the present invention, and that such modifications and adaptations are intended to be within the scope of the appended claims.

Claims (10)

1. A robotic joint with an output encoder, comprising:

the synchronous motor (1) comprises a shell (107), a rotor assembly, a stator (103) and a motor controller (109), wherein the stator (103) is fixedly connected in an inner cavity of the shell (107), the rotor assembly is rotationally connected in the inner cavity of the shell (107), the motor controller (109) is fixedly connected in the shell (107), the rotor assembly comprises a motor end encoder magnet (104), and the motor end encoder magnet (104) is used for providing position feedback of the rotor assembly to the motor controller (109);

The planetary reduction gearbox (2), the planetary reduction gearbox (2) comprises an output mechanism and a reduction mechanism (206), the reduction mechanism (206) comprises a fixed component which keeps the relative position with the shell (107) unchanged and a rotating component which is connected with the rotor component, the output mechanism is connected with the rotating component, and the rotor component drives the rotating component and the output mechanism to rotate;

an output end encoder (3), wherein the output end encoder (3) comprises an output end encoder circuit board (301), an output end encoder magnet (302), an encoder output gear (303) and an encoder input gear (308); the encoder input gear (308) is connected with the output mechanism, the output mechanism drives the encoder input gear (308) to rotate, the encoder input gear (308) is used for driving the encoder output gear (303) to rotate, the output end encoder magnet (302) is installed on the encoder output gear (303), and the output end encoder circuit board (301) is used for receiving position feedback of the output mechanism provided by the output end encoder magnet (302).

2. The robot joint with an output end encoder according to claim 1, wherein the synchronous motor is an outer rotor synchronous motor, the rotor assembly further comprises an outer rotor holder (101) and an outer rotor steel ring (102), the outer rotor steel ring (102) is fixedly connected to the outer rotor holder (101), the motor end encoder magnet (104) is mounted at one end of the outer rotor holder (101) facing the motor controller (109), and the outer rotor holder (101) is rotatably connected with the casing (107) through a rotor bearing (105).

3. The robot joint with an output end encoder according to claim 1 or 2, characterized in that the output mechanism comprises an end cover (202), an output flange (201) and an output planet carrier (203) which are arranged in sequence, the end cover (202) is fixedly connected with one end of the casing (107) far away from the motor controller (109), the output flange (201) is rotatably connected with the end cover (202), and the output planet carrier (203) is fixedly connected with the output flange (201) so that the output planet carrier (203) and the output flange (201) rotate together relative to the end cover (202).

4. A robotic joint with output end encoder according to claim 3, characterized in that the fixed assembly of the reduction mechanism (206) comprises a fixed ring gear (2061), the fixed ring gear (2061) being fixedly connected with the end cap (202); the rotating assembly of the speed reducing mechanism (206) comprises a planetary gear (2063) set, the planetary gear (2063) set is installed in an inner cavity of the fixed ring gear (2061), and the planetary gear (2063) set is respectively connected with the output planet carrier (203) and the outer rotor holder (101) so that the planetary gear (2063) set and the output planet carrier (203) are driven to rotate when the outer rotor holder (101) rotates, and the planetary gear (2063) set is used for controlling the rotation speed ratio of the outer rotor holder (101) to the output planet carrier (203).

5. The robot joint with an output end encoder according to claim 4, characterized in that the planetary gear (2063) set comprises a sun gear (2062) and a plurality of planetary gears (2063) located at the periphery of the sun gear (2062), the sun gear (2062) is arranged at the center of an inner cavity of the fixed ring gear (2061), an inner ring gear is arranged at an inner ring of the fixed ring gear (2061), the planetary gears (2063) are arranged between the inner ring gear and the sun gear (2062), the planetary gears (2063) are meshed with an outer ring of the sun gear (2062) and the inner ring gear at the same time, and the sun gear (2062) is connected with the outer rotor holder (101) so that the outer rotor holder (101) drives the sun gear (2062) to rotate.

6. The robot joint with output end encoder according to claim 5, characterized in that a plurality of gear mounting grooves are provided on the output planet carrier (203), and the planetary gear (2063) is placed in the gear mounting grooves, so that when the sun gear (2062) drives the planetary gear (2063) to rotate, the planetary gear (2063) drives the output planet carrier (203) to rotate.

7. A robot joint with an output end encoder according to claim 3, characterized in that the output end encoder (3) further comprises an encoder output gear (303) bearing, an encoder output gear holder (306), a bearing cavity for mounting the encoder output gear (303) bearing is provided on the encoder output gear holder (306), a connecting shaft assembled with the encoder output gear (303) bearing is provided on the encoder output gear (303), so that the encoder output gear (303) is rotatably mounted on the encoder output gear holder (306), and the encoder output gear holder (306) is fixedly connected to the end cover (202).

8. A robot joint with an output encoder according to claim 3, characterized in that the output encoder (3) further comprises an encoder transmission gear (307), the encoder input gear (308) is mounted on the outer ring of the output planet carrier (203) or the output flange (201) so that the encoder input gear (308) rotates together with the output planet carrier (203) or the output flange (201), the encoder transmission gear (307) is arranged between the encoder input gear (308) and the encoder output gear (303), both sides of the encoder transmission gear (307) are respectively meshed with the encoder input gear (308) and the encoder output gear (303), and the power of the encoder input gear (308) is transmitted to the encoder output gear (303) through the encoder transmission gear (307).

9. The robot joint with output end encoder according to claim 1, characterized in that the motor controller (109) is a motor controller (109) of an on-board encoder, the motor controller (109) of the on-board encoder is integrated with a motor end encoder for measuring the angular displacement of the outer rotor holder (101), and the output end encoder circuit board (301) is integrated with an encoder for measuring the angular displacement of the output flange (201).

10. The control method of the robot joint with the output end encoder is characterized by comprising the following steps of:

s1, recording an electric signal of an outer rotor retainer zero position in a rotor assembly and an electric signal of an output flange zero position in an output mechanism by a motor controller;

s2, when the motor controller is electrified and operated, a motor end encoder on the motor controller converts the absolute position of the outer rotor retainer into an electric signal and sends the electric signal to the motor controller, and the motor controller records the number of turns of the outer rotor retainer according to a single-turn absolute encoding electric signal output by the motor end encoder on the motor end encoder and converts the single-turn absolute encoding electric signal into a multi-turn absolute encoding;

s3, judging whether the motor controller is powered off and restarted, if so, converting the motor end encoder on the motor controller into an electric signal according to the position of the outer rotor retainer, converting the output end encoder into an electric signal according to the position of the output flange, and simultaneously transmitting the electric signal to the motor controller, so that the motor controller obtains current readings of the motor end encoder and the output end encoder; if not, continuing to execute the step S2;

s4, the motor controller calculates the number of turns of the outer rotor retainer according to the reduction ratio of the planetary reduction gearbox and the readings of the two encoders, namely the motor end encoder and the output end encoder, so as to calculate the absolute position of the output flange relative to the zero point of the outer rotor retainer;

The robotic joint is the robotic joint of any one of claims 1-9.

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