Two-DOF direct drive joint

Abstract

The present application relates to the technical field of robot joint drive structure, and specifically discloses a dual-degree-of-freedom direct-drive joint, including one axis and two axes; both the one axis and the two axes are driven by brushless permanent magnet motors and a first-stage planetary reducer with a reduction ratio of ≤10; the motor shafts of the brushless permanent magnet motors of the one axis and the two axes are placed concentrically relative to each other; the output of the one axis is connected to the motor housing of the two axis, and the two axes as a whole can rotate 360° around the one axis. The dual-degree-of-freedom direct-drive joint of the present invention adopts a brushless permanent magnet torque motor + a low reduction ratio (reduction ratio ≤10) planetary reducer. The brushless permanent magnet torque motor provides a reliable large torque, and the low reduction ratio reducer achieves a lower internal friction, which is more conducive to the realization of joint force control.

Description

Technical Field

[0001] The present application relates to the technical field of robot joint drive structures, and in particular to a dual-degree-of-freedom direct-drive joint. Background Art

[0002] Most of the common articulated manipulators and leg-type robots on the market use a transmission solution of servo motor + high reduction ratio reducer. Due to the use of a large reduction ratio reducer, the friction in the joint is large, which is not conducive to the implementation of the joint force control algorithm. In addition, since harmonic reducers are mostly used with a large reduction ratio, although high torque density output is achieved, additional spring structures must be added to achieve compliance in order to achieve better control effects, but at the same time the force control bandwidth is reduced. This transmission solution does not show advantages in terms of structural complexity, cost, and difficulty. This solution is mostly a single joint with a high degree of integration, which is mostly installed directly at the required joint. Taking the leg-type as an example, each joint needs to be installed with this joint, which will increase the leg inertia and affect the leg swing speed. Summary of the invention

[0003] The present invention proposes a dual-degree-of-freedom direct-drive joint to improve various problems existing in the prior art using a servo motor + a high reduction ratio reducer and a harmonic reducer.

[0004] To achieve the above-mentioned purpose, the present invention provides a dual-degree-of-freedom direct-drive joint, comprising one axis and two axes; both the one axis and the two axes are driven by a brushless permanent magnet motor and a first-stage planetary reducer with a reduction ratio of ≤10; the motor shafts of the brushless permanent magnet motors of the one axis and the two axes are concentrically placed opposite to each other; the output of the one axis is connected to the motor housing of the two axes, and the two axes as a whole can rotate 360° around the one axis.

[0005] Specifically, one shaft includes a shaft motor housing, a shaft motor stator, a shaft end cover I, a shaft bearing I, a shaft end cover II, a shaft code disk, a shaft code disk rotating shaft, a shaft motor shaft, a shaft motor rotor, a shaft outer cover, a shaft bearing II, a shaft planetary reducer, a shaft outer planetary carrier, a shaft end cover III, a shaft inner planetary carrier, a shaft bearing III, a shaft end cover IV and a shaft bearing IV; the second shaft includes a second shaft motor housing, a second shaft motor housing rear cover, a second shaft motor stator, a second shaft motor rotor, a second shaft end cover I, a second shaft bearing I, a second shaft end cover II, a second shaft code disk, a second shaft code disk rotating shaft, a second shaft motor shaft, a second shaft planetary reducer inner gear ring, a second shaft planetary reducer, a second shaft planetary carrier flange, a second shaft inner planetary carrier, Two-axis bearing II, two-axis end cover III and two-axis bearing III; one-axis motor stator is connected to one-axis motor housing; one-axis motor rotor is connected to one-axis motor shaft; one-axis bearing I is placed between one-axis motor housing and one end of one-axis motor shaft, and is fixed by one-axis end cover I and one-axis end cover II; the other end of one-axis motor shaft is connected to the sun gear of one-axis planetary reducer, the input of one-axis planetary reducer is the sun gear, and the output is one-axis outer planetary carrier; one-axis bearing III is placed between one-axis motor shaft and one-axis inner planetary carrier, and is fixed by one-axis end cover III and one-axis end cover IV; one-axis bearing IV is placed between one-axis outer planetary carrier and sun gear in one-axis planetary reducer, one-axis bearing I and one-axis bearing IV are opposite The first-axis motor shaft forms a two-point stable support; the first-axis code disk is used to measure the rotation angle of the first-axis motor, the outer shell of the first-axis code disk is connected to the outer shell of the first-axis motor, the rotating part inside the first-axis code disk is connected to the first-axis code disk rotating shaft, and the first-axis code disk rotating shaft is connected to the first-axis motor shaft; the first-axis bearing II is placed between the first-axis outer cover and the first-axis outer planetary frame, and the first-axis bearing II rotates as the first-axis outer planetary frame rotates; the second-axis motor stator is connected to the second-axis motor shell; the second-axis motor rotor is connected to the second-axis motor shaft; the second-axis bearing I is placed between the second-axis motor shell rear cover and one end of the second-axis motor shaft, and is fixed by the second-axis end cover I and the second-axis end cover II; the other end of the second-axis motor shaft is connected to the sun gear of the second-axis planetary reducer, and the second-axis planetary reducer The input is the sun gear, and the output is the second-axis planetary carrier flange; the second-axis bearing II is placed between the second-axis motor shaft and the second-axis planetary carrier flange, and is fixed by the second-axis end cover III; the second-axis bearing III is placed between the sun gear of the second-axis planetary reducer and the first-axis outer planetary carrier, and forms a two-point stable support for the second-axis motor shaft through the second-axis bearing I and the second-axis bearing III; the second-axis code disk is used to measure the rotation angle of the second-axis motor, the outer shell of the second-axis code disk is connected to the rear cover of the second-axis motor outer shell, the rotating part inside the second-axis code disk is connected to the second-axis code disk rotating shaft, and the second-axis code disk rotating shaft is connected to the second-axis motor shaft; the first axis is connected to the second-axis planetary reducer inner gear ring of the second axis through the first-axis outer planetary carrier, and the second-axis planetary reducer inner gear ring is connected to the second-axis motor outer shell.

[0006] Furthermore, a shaft heat sink is mounted on the shaft motor housing.

[0007] Furthermore, two-axis heat sinks are mounted on the housing of the two-axis motor.

[0008] Furthermore, the stator of the single-axis motor and the housing of the single-axis motor are bonded with glue.

[0009] Furthermore, the motor rotor and the motor shaft are bonded together using glue.

[0010] Furthermore, the stator of the two-axis motor is connected to the housing of the two-axis motor by gluing.

[0011] Furthermore, the two-axis motor rotor is connected to the two-axis motor shaft by gluing.

[0012] Furthermore, the installation of the one-axis code disc and the two-axis code disc both adopts an embedded structure.

[0013] Furthermore, the second-axis planetary carrier flange is an external output shaft and can be connected with a chain, a connecting rod, a belt or a wire rope.

[0014] The present invention has the following beneficial effects:

[0015] 1. The dual-degree-of-freedom direct-drive joint of the present invention adopts a brushless permanent magnet torque motor + a low reduction ratio (reduction ratio ≤ 10) planetary reducer. The brushless permanent magnet torque motor provides a reliable large torque, and the low reduction ratio reducer achieves a lower internal friction, which is more conducive to the realization of joint force control;

[0016] 2. The double-degree-of-freedom joint is composed of two concentrically arranged motors. The two shafts have the same structure and components. They are all nested and can be split into two independent joints. They can realize both single-degree-of-freedom joints and double-degree-of-freedom joints. Different degrees of freedom structures are selected for different applications.

[0017] 3. The use of a small reduction ratio reducer increases the bandwidth, reduces internal friction, reduces the difficulty of joint force control, and is more conducive to achieving reliable force-controlled walking control. This structural joint has the advantages of high torque density and high reverse drive performance, and does not require additional spring structures and high-cost harmonic reducers. It has great advantages in control difficulty, cost, and structural complexity;

[0018] 4. The dual-degree-of-freedom direct-drive joint can better reduce the leg inertia of the leg-footed robot. The motor, reducer and other mechanisms can be arranged on the top, and the torque is transmitted to the required joints downward through lightweight transmission mechanisms such as belts and chains. Unlike common integrated joints, it does not have to be installed at the required rotating joints, thereby achieving a low-inertia design, which is more conducive to increasing the leg swinging frequency and increasing the walking speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is an overall schematic diagram of an axis;

[0021] Figure 2 A cross-sectional view of an axis;

[0022] Figure 3 An exploded diagram of one axis;

[0023] Figure 4 It is the overall schematic diagram of the two axes;

[0024] Figure 5 It is a cross-sectional view of the two axes;

[0025] Figure 6 It is an exploded diagram of two axes;

[0026] Figure 7 This is the assembly drawing of the first and second axes;

[0027] Figure 8 It is a cross-sectional view of the first and second axes.

[0028] In the figure: 1.1-a shaft heat sink, 1.2-a shaft motor housing, 1.3-a shaft motor stator, 1.4-a shaft end cover I, 1.5-a shaft bearing I, 1.6-a shaft end cover II, 1.7-a shaft code disk, 1.8-a shaft code disk shaft, 1.9-a shaft motor shaft, 1.10-a shaft motor rotor, 1.11-a shaft outer cover, 1.12-a shaft bearing II; 1.13-a shaft planetary reducer, 1.14-a shaft outer planetary carrier, 1.15-a shaft end cover III, 1.16-a shaft inner planetary carrier, 1.17-a shaft bearing III, 1.18-a shaft end cover IV, 1.19-a shaft bearing IV,

[0029] 2.1-second-axis heat sink, 2.2-second-axis motor housing, 2.3-second-axis motor housing back cover, 2.4-second-axis motor stator, 2.5-second-axis motor rotor, 2.6-second-axis end cover I, 2.7-second-axis bearing I, 2.8-second-axis end cover II, 2.9-second-axis code disk, 2.10-second-axis code disk shaft, 2.11-second-axis motor shaft, 2.12-second-axis planetary reducer inner gear ring, 2.13-second-axis planetary reducer, 2.14-second-axis planetary carrier flange, 2.15-second-axis inner planetary carrier, 2.16-second-axis bearing II, 2.17-second-axis end cover III, 2.18-second-axis bearing III. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present embodiment provides a low-cost, high-reliability dual-degree-of-freedom direct-drive joint, comprising one axis and two axes; both the one axis and the two axes are driven by brushless permanent magnet motors and a first-stage planetary reducer with a reduction ratio of ≤10; the motor shafts of the brushless permanent magnet motors of the one axis and the two axes are concentrically arranged relative to each other; the output of the one axis is connected to the motor housing of the two axis, and the two axes as a whole can rotate 360° around the one axis.

[0032] A shaft includes a shaft heat sink 1.1, a shaft motor housing 1.2, a shaft motor stator 1.3, a shaft end cover I1.4, a shaft bearing I1.5, a shaft end cover II1.6, a shaft code disk 1.7, a shaft code disk shaft 1.8, a shaft motor shaft 1.9, a shaft motor rotor 1.10, a shaft outer cover 1.11, a shaft bearing II1.12, a shaft planetary reducer 1.13, a shaft outer planetary carrier 1.14, a shaft end cover III1.15, a shaft inner planetary carrier 1.16, a shaft bearing III1.17, a shaft end cover IV1.18 and a shaft bearing IV1.19; a shaft motor stator 1 .3 is bonded to the motor housing 1.2 by glue, and a heat sink 1.1 is installed on the motor housing 1.2 to release the heat generated by the motor during the operation of the joint; the motor rotor (1.10) is bonded to the motor shaft 1.9 by glue; the bearing I1.5 is placed between the motor housing 1.2 and one end of the motor shaft 1.9, and is fixed by an end cover I1.4 and an end cover II1.6; the other end of the motor shaft 1.9 is connected to the sun gear of the planetary reducer 1.13, the input of the planetary reducer 1.13 is the sun gear, and the output is the outer planet carrier 1. 14; a shaft bearing III1.17 is placed between a shaft motor shaft 1.9 and a shaft inner planetary carrier 1.16, and is fixed by a shaft end cover III1.15 and a shaft end cover IV1.18; a shaft bearing IV1.19 is placed between a shaft outer planetary carrier 1.14 and a sun gear in a shaft planetary reducer 1.13, and a shaft bearing I1.5 and a shaft bearing IV1.19 form a two-point stable support for the shaft motor shaft 1.9; a shaft code disk 1.7 is used to measure the rotation angle of the shaft motor, and the housing of the shaft code disk 1.7 is connected to the housing 1.2 of the shaft motor, and the rotating part inside the shaft code disk 1.7 is connected to the shaft code disk rotating shaft 1.8 is connected, the first-axis code disk shaft 1.8 is connected to the first-axis motor shaft 1.9, thereby realizing the indirect connection between the rotating part of the first-axis code disk 1.7 and the first-axis motor shaft 1.9, and the installation of the first-axis code disk 1.7 adopts an embedded structure, so that it is embedded inside the joint, making the overall joint more beautiful, without abrupt parts, and reducing the danger during operation; the first-axis bearing II1.12 is placed between the first-axis outer cover 1.11 and the first-axis outer planetary carrier 1.14, and the first-axis bearing II1.12 rotates with the rotation of the first-axis outer planetary carrier 1.14; the first-axis outer planetary carrier 1.14 is the output flange of the first axis, which is connected to the second-axis motor housing 2.2.

[0033] The second axis includes a second axis heat sink 2.1, a second axis motor housing 2.2, a second axis motor housing back cover 2.3, a second axis motor stator 2.4, a second axis motor rotor 2.5, a second axis end cover I 2.6, a second axis bearing I 2.7, a second axis end cover II 2.8, a second axis code disk 2.9, a second axis code disk shaft 2.10, a second axis motor shaft 2.11, a second axis planetary reducer inner gear ring 2.12, a second axis planetary reducer 2.13, a second axis planetary carrier flange 2.14, a second axis inner planetary carrier 2.15, a second axis bearing II 2.16, and a second axis end cover III 2.1 7 and the second-axis bearing III2.18; the second-axis motor stator 2.4 and the second-axis motor housing 2.2 are glued, and the second-axis heat sink 2.1 is installed on the second-axis motor housing 2.2 to release the heat generated by the motor during the operation of the joint; the second-axis motor rotor 2.5 and the second-axis motor shaft 2.11 are glued; the second-axis bearing I2.7 is placed between the second-axis motor housing rear cover 2.3 and one end of the second-axis motor shaft 2.11, and is fixed by the second-axis end cover I2.6 and the second-axis end cover II2.8; the other end of the second-axis motor shaft 2.11 is fixed to the second-axis The sun gear of the planetary reducer 2.13 is connected, the input of the two-axis planetary reducer 2.13 is the sun gear, and the output is the two-axis planetary frame flange 2.14; the two-axis bearing II2.16 is placed between the two-axis motor shaft 2.11 and the two-axis planetary frame flange 2.14, and is fixed by the two-axis end cover III2.17; the two-axis bearing III2.18 is placed between the sun gear of the two-axis planetary reducer 2.13 and the one-axis outer planetary frame 1.14, and the two-point stability is formed on the two-axis motor shaft 2.11 through the two-axis bearing I2.7 and the two-axis bearing III2.18. Support; the two-axis code disk 2.9 is used to measure the rotation angle of the two-axis motor. The shell of the two-axis code disk 2.9 is connected to the back cover 2.3 of the two-axis motor shell. The rotating part inside the two-axis code disk 2.9 is connected to the two-axis code disk rotating shaft 2.10. The two-axis code disk rotating shaft 2.10 is connected to the two-axis motor shaft 2.11, thereby realizing the indirect connection between the rotating part inside the two-axis code disk 2.9 and the two-axis motor shaft 2.11. The installation of the two-axis code disk 2.9 adopts an embedded structure, so that it is embedded in the joint, making the overall joint more beautiful, without abrupt parts, and reducing the danger during operation.

[0034] The first shaft is connected to the second shaft planetary reducer inner gear ring 2.12 through the first shaft outer planetary carrier 1.14, and the second shaft planetary reducer inner gear ring 2.12 is connected to the second shaft motor housing (2.2), so the second shaft as a whole becomes the output of the first shaft, and the second shaft as a whole can rotate 360 ​​degrees around the first shaft; the second shaft planetary carrier flange 2.14 of the second shaft is the external output shaft, which can be connected to transmission mechanisms such as chains, connecting rods, wire ropes, belts, etc. for transmission.

[0035] The above-mentioned dual-degree-of-freedom direct-drive joint has two rotational degrees of freedom and can also be split into independent degrees of freedom joints. The axes of the two rotational degrees of freedom are one axis and two axes respectively. Both axes are driven by brushless permanent magnet motor + low reduction ratio (reduction ratio ≤ 10) first-level planetary reducer. The motor shafts are placed concentrically relative to each other, and the output shaft of one axis is connected to the motor housing of the second axis. The two axes can rotate 360° around one axis as a whole. The wide range of rotation angles provides a wide range of motion space for the joint. The output end of the two axes is a disc flange. If 360° rotation is required, a chain or synchronous belt transmission mechanism needs to be connected to transfer power to the downward joint. If high rigidity is to be achieved, a connecting rod mechanism can be connected. The dual-free joint of the present invention is installed in a nested manner, and a motor, a reducer, and a multi-turn absolute value encoder are integrated internally, which can better realize the joint force control and the low inertia design of the leg-foot robot. The joints are nested with integrated motors, reducers, encoders and other transmission and control mechanisms. The motors are coaxially arranged relative to each other. The components of the two joints are the same, with good interchangeability. The integrated joint solution using harmonic reducers is eliminated, and the passband bandwidth is high. It has obvious advantages in terms of control difficulty, cost, and structural complexity. The output ends are all integrated in the joints, and only lightweight transmission mechanisms such as connecting rods, belts, chains, and wire ropes are needed to transmit power to the downward joints. It is not necessary to install all the mechanisms on the required joints, which can further reduce the low inertia of the legs, realize the upward shift of the center of gravity of the legs, increase the frequency of leg swinging, and increase the speed.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-degree-of-freedom direct-drive joint, characterized in that: Including one axis and two axes; The first and second axes are driven by brushless permanent magnet motors and first-stage planetary reducers with a reduction ratio of ≤10; The motor shafts of the one-axis and the second-axis brushless permanent magnet motors are placed concentrically relative to each other; The output of the first shaft is connected to the motor housing of the second shaft, and the two shafts as a whole can rotate 360° around the first shaft; The shaft comprises a shaft motor housing (1.2), a shaft motor stator (1.3), a shaft end cover I (1.4), a shaft bearing I (1.5), a shaft end cover II (1.6), a shaft code disk (1.7), a shaft code disk rotating shaft (1.8), a shaft motor shaft (1.9), a shaft motor rotor (1.10), a shaft outer cover (1.11), a shaft bearing II (1.12), a shaft planetary reducer (1.13), a shaft outer planetary carrier (1.14), a shaft end cover III (1.15), a shaft inner planetary carrier (1.16), a shaft bearing III (1.17), a shaft end cover IV (1.18) and a shaft bearing IV (1.19); The second shaft comprises a second shaft motor housing (2.2), a second shaft motor housing rear cover (2.3), a second shaft motor stator (2.4), a second shaft motor rotor (2.5), a second shaft end cover I (2.6), a second shaft bearing I (2.7), a second shaft end cover II (2.8), a second shaft code disk (2.9), a second shaft code disk rotating shaft (2.10), a second shaft motor shaft (2.11), a second shaft planetary reducer inner gear ring (2.12), a second shaft planetary reducer (2.13), a second shaft planetary frame flange (2.14), a second shaft inner planetary frame (2.15), a second shaft bearing II (2.16), a second shaft end cover III (2.17) and a second shaft bearing III (2.18); The one-axis motor stator (1.3) is connected to the one-axis motor housing (1.2); The one-axis motor rotor (1.10) is connected to the one-axis motor shaft (1.9); The first shaft bearing I (1.5) is placed between the first shaft motor housing (1.2) and one end of the first shaft motor shaft (1.9), and is fixed by a first shaft end cover I (1.4) and a first shaft end cover II (1.6); The other end of the one-axis motor shaft (1.9) is connected to the sun gear of the one-axis planetary reducer (1.13); the input of the one-axis planetary reducer (1.13) is the sun gear, and the output is the one-axis outer planetary carrier (1.14); The first shaft bearing III (1.17) is placed between the first shaft motor shaft (1.9) and the first shaft inner planetary carrier (1.16), and is fixed by a first shaft end cover III (1.15) and a first shaft end cover IV (1.18); The first-axis bearing IV (1.19) is placed between the first-axis outer planetary carrier (1.14) and the sun gear in the first-axis planetary reducer (1.13), and the first-axis bearing I (1.5) and the first-axis bearing IV (1.19) form a two-point stable support for the first-axis motor shaft (1.9); The one-axis code disc (1.7) is used to measure the rotation angle of the one-axis motor; the outer shell of the one-axis code disc (1.7) is connected to the outer shell (1.2) of the one-axis motor; the rotating part inside the one-axis code disc (1.7) is connected to the one-axis code disc rotating shaft (1.8); and the one-axis code disc rotating shaft (1.8) is connected to the one-axis motor shaft (1.9); The first shaft bearing II (1.12) is placed between the first shaft outer cover (1.11) and the first shaft outer planetary carrier (1.14), and the first shaft bearing II (1.12) rotates along with the rotation of the first shaft outer planetary carrier (1.14); The two-axis motor stator (2.4) is connected to the two-axis motor housing (2.2); The dual-axis motor rotor (2.5) is connected to the dual-axis motor shaft (2.11); The second shaft bearing I (2.7) is placed between the second shaft motor housing rear cover (2.3) and one end of the second shaft motor shaft (2.11), and is fixed by the second shaft end cover I (2.6) and the second shaft end cover II (2.8); The other end of the two-axis motor shaft (2.11) is connected to the sun gear of the two-axis planetary reducer (2.13); the input of the two-axis planetary reducer (2.13) is the sun gear, and the output is the two-axis planetary carrier flange (2.14); The second-axis bearing II (2.16) is placed between the second-axis motor shaft (2.11) and the second-axis planetary frame flange (2.14), and is fixed by the second-axis end cover III (2.17); The second-axis bearing III (2.18) is placed between the sun gear of the second-axis planetary reducer (2.13) and the one-axis outer planetary carrier (1.14), and the second-axis bearing I (2.7) and the second-axis bearing III (2.18) form a two-point stable support for the second-axis motor shaft (2.11); The two-axis code disc (2.9) is used to measure the rotation angle of the two-axis motor. The housing of the two-axis code disc (2.9) is connected to the rear cover (2.3) of the housing of the two-axis motor. The rotating part inside the two-axis code disc (2.9) is connected to the two-axis code disc rotating shaft (2.10). The two-axis code disc rotating shaft (2.10) is connected to the two-axis motor shaft (2.11). The first shaft is connected to the inner gear ring (2.12) of the second shaft planetary reducer via the first shaft outer planetary carrier (1.14), and the inner gear ring (2.12) of the second shaft planetary reducer is connected to the second shaft motor housing (2.2).

2. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The single-axis motor housing (1.2) is provided with a single-axis heat sink (1.1).

3. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The dual-axis motor housing (2.2) is provided with dual-axis heat sinks (2.1).

4. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The one-axis motor stator (1.3) and the one-axis motor housing (1.2) are bonded together using glue.

5. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The single-axis motor rotor (1.10) and the single-axis motor shaft (1.9) are bonded together using glue.

6. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The two-axis motor stator (2.4) and the two-axis motor housing (2.2) are connected by gluing.

7. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The dual-axis motor rotor (2.5) and the dual-axis motor shaft (2.11) are connected by gluing.

8. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The one-axis code disc (1.7) and the two-axis code disc (2.9) are both installed in an embedded structure.

9. The dual-degree-of-freedom direct-drive joint according to claim 1, characterized in that: The two-axis planetary frame flange (2.14) is an external output shaft and can be connected with a chain, a connecting rod, a belt or a steel wire rope.

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