Linear joint of humanoid robot

Abstract

The humanoid robot linear joint comprises a planetary roller screw, an angle encoder is mounted on the outer side of the planetary roller screw, a six-dimensional force sensor is fixedly mounted on one side of the planetary roller screw, a mounting seat is fixedly mounted on the outer side of the planetary roller screw, and a reading head is fixedly mounted at the top of the mounting seat; the screw rod can drive six pin rollers in the nut to rotate when rotating, so that the nut linearly moves on the outer side of the screw rod, the linear joints of the humanoid machine operate, and the joints can stretch, retract and the like; the planetary roller lead screw is adopted for carrying out linear motion at the joints, so that the smoothness of the joints can be guaranteed, large axial loads and radial loads can be borne, meanwhile, the advantages of being high in precision and rigidity, long in service life and the like are achieved, in addition, due to multi-line contact among the rollers, the lead screw and the nut, transmission is more stable, and vibration and noise are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of robot joints, and particularly to a linear joint for a humanoid robot. Background Art

[0002] With the rapid progress of technology, humanoid robots, as the product of the deep integration of artificial intelligence and robotics technology, are gradually moving from science fiction concepts to real-world applications. However, to achieve the wide application of humanoid robots in these fields, the performance of their joints is crucial. As the movement hub of humanoid robots, joints directly affect the movement flexibility, stability, and accuracy of the robots. As an important part of humanoid robot joints, linear joints are responsible for realizing the linear movement of the robot in a specific direction, such as the extension of the arm, the stepping of the leg, etc. The quality of their performance is directly related to the overall movement performance of the robot.

[0003] Currently, the commonly used transmission methods for linear joints of humanoid robots mainly include gear-rack transmission, synchronous belt transmission, and ball screw transmission, etc. Although gear-rack transmission has a simple structure, it has relatively large friction and gaps during the transmission process, resulting in low transmission efficiency. Moreover, with the increase of service time, the wear will be further aggravated, affecting the transmission accuracy. Although synchronous belt transmission has a certain flexibility, it is prone to elastic deformation when bearing a large load, resulting in a decrease in transmission accuracy and being difficult to meet the requirements of high-precision motion control. Although ball screw transmission has high transmission efficiency and accuracy, it is prone to vibration and noise during high-speed movement, and its load-bearing capacity is limited, making it difficult to meet the usage requirements of humanoid robots under complex working conditions. In addition, most of the existing linear joints lack an effective force monitoring and feedback mechanism, and cannot meet the requirements of humanoid robots for safety and reliability. Summary of the Invention

[0004] The purpose of the present invention is to provide a linear joint for a humanoid robot to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A linear joint for a humanoid robot, including a planetary roller screw, an angle encoder is installed on the outer side of the planetary roller screw, a six-axis force sensor is fixedly installed on one side of the planetary roller screw, a mounting seat is fixedly installed on the outer side of the planetary roller screw, a reading head is fixedly installed on the top of the mounting seat, a support and limit component is installed on the top of the mounting seat, and a scale base is fixedly installed at the bottom of the support and limit component, and a grating scale is fixedly installed at the bottom of the scale base.

[0006] Preferably, the planetary roller screw comprises a lead screw and a nut. One end of the lead screw is fixedly installed with a rotating shaft. Planet carriers are clamped and installed on both sides of the inner cavity of the nut. Six mounting holes are respectively formed in the interiors of the planet carriers. Six rollers are rotatably installed in the interior of the nut. Mounting columns are fixedly installed at both ends of the six rollers, and the mounting columns are movably installed in the mounting holes.

[0007] Preferably, the angle encoder is installed on the outer side of the rotating shaft. A mounting disc is fixedly installed on one side of the nut. The six-axis force sensor is installed on one side of the mounting disc.

[0008] Preferably, a frameless torque motor is fixedly installed on the outer side of the end of the rotating shaft away from the lead screw. A bearing seat is installed at the end of the lead screw away from the rotating shaft.

[0009] Preferably, the lead screw is movably installed inside the nut, and the outer sides of the rollers are meshed with the outer side of the lead screw.

[0010] Preferably, internal gear rings are installed on both sides of the inner cavity of the nut. Rotating gears are fixedly installed on the outer sides of the mounting columns at both ends of the six rollers. The outer sides of the connecting bars are meshed with the inner sides of the internal gear rings. Retaining rings are clamped and installed in the interiors of both ends of the nut.

[0011] Preferably, the support and limit assembly comprises a mounting top plate. Fixed vertical plates are fixedly installed at the bottoms of the two moving joint ends of the mounting top plate. Two slide bar grooves are symmetrically formed at the bottom of the mounting top plate. Limit slide bars are slidably installed in the two slide bar grooves.

[0012] Preferably, the ends of the two fixed vertical plates away from the mounting top plate are respectively fixedly connected to the outer sides of the frameless torque motor and the bearing seat. The ends of the limit slide bars away from the planet carriers are fixedly connected to the top of the mounting seat.

[0013] Preferably, the scale base is fixedly installed at the bottom of the mounting top plate. The position of the grating scale corresponds to the position of the reading head.

[0014] Preferably, a fixed joint is fixedly installed at the top of the mounting top plate. A moving joint is slidably installed on the outer side of the fixed joint. One end of the moving joint is fixedly installed with a connecting plate one. The moving end of the fixed joint is fixedly installed with a connecting plate two. Two moving slide bars are symmetrically fixedly installed on the outer side of the nut. Slide grooves are formed on both sides of the fixed joint. The moving slide bars are slidably installed in the slide grooves, and the ends of the moving slide bars away from the nut are fixedly connected to the inner side of the moving joint.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: When the screw rod is rotated, it can drive the six rollers inside the nut to rotate, causing the nut to move linearly outside the screw rod, thereby enabling the linear joints of the humanoid robot to operate, achieving movements such as joint extension and contraction. Using a planetary roller screw for linear motion at the joints can ensure smoothness at the joints, and can bear large axial loads and radial loads. At the same time, it has characteristics such as high precision, high stiffness, and long lifespan. In addition, the multi-line contact between the rollers and the screw rod and nut makes the transmission more stable, reducing vibration and noise. The cooperation of the angle encoder and the ruler base can calculate the linear operation accuracy of the joint. The angle encoder is installed on the rotating shaft and can measure the rotation angle of the rotating shaft in real time and convert it into an electrical signal for output. The ruler base is installed in the moving direction of the nut and is used to accurately measure the linear displacement of the nut. The calculation formula is: Linear motion accuracy = Angle encoder value * Pitch - Ruler base value. When the linear motion accuracy exceeds the set range, the control system can timely adjust the output of the frameless torque motor to compensate the transmission system, thereby ensuring the linear motion accuracy of the joint. In addition, the six-axis force sensor can detect the forces in all aspects during joint operation. It can detect the forces and torques in six directions when the joint is operating in real time, including the forces in three orthogonal directions and the torques in three orthogonal directions. By analyzing the data collected by the six-axis force sensor, the force conditions of the joint in different motion states can be understood, providing an important basis for the motion control, force control, and safety protection of the robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic three-dimensional external structure diagram of the present invention.

[0017] Figure 2 It is a schematic cross-sectional three-dimensional structure diagram of the present invention.

[0018] Figure 3 It is a schematic partial three-dimensional structure diagram of the present invention.

[0019] Figure 4 It is a schematic partial bottom view structure diagram of the present invention.

[0020] Figure 5 It is a schematic structure diagram of the planetary roller screw of the present invention.

[0021] Figure 6 It is a schematic partial three-dimensional structure diagram of the planetary roller screw of the present invention.

[0022] Figure 7 It is a schematic partial side view structure diagram of the planetary roller screw of the present invention.

[0023] In the figure: 1, fixed joint; 2, movable joint; 3, first connecting plate; 4, chute; 5, second connecting plate; 6, movable slide bar; 7, fixed vertical plate; 8, mounting seat; 9, frameless torque motor; 10, angle encoder; 11, rotating shaft; 12, lead screw; 13, nut; 14, six-axis force sensor; 15, bearing seat; 16, limit slide bar; 17, reading head; 18, mounting top plate; 19, mounting disc; 20, connecting bar; 21, grating scale; 22, scale seat; 23, slide bar groove; 24, planet carrier; 25, retaining ring; 26, roller; 27, mounting hole; 28, mounting post; 29, rotating gear; 30, internal gear ring. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] Please refer to Figures 1-7 , the present invention provides a technical solution: a linear joint of a humanoid robot, including a planetary roller screw. An angle encoder 10 is installed on the outer side of the planetary roller screw. A six-axis force sensor 14 is fixedly installed on one side of the planetary roller screw. A mounting seat 8 is fixedly installed on the outer side of the planetary roller screw. A reading head 17 is fixedly installed on the top of the mounting seat 8. A support and limit assembly is installed on the top of the mounting seat 8, and a scale seat 22 is fixedly installed at the bottom of the support and limit assembly. A grating scale 21 is fixedly installed at the bottom of the scale seat 22. The planetary roller screw includes a lead screw 12 and a nut 13. A rotating shaft 11 is fixedly installed at one end of the lead screw 12. Planet carriers 24 are clamped and installed on both sides of the inner cavity of the nut 13. Six mounting holes 27 are respectively opened in the interiors of the planet carriers 24. Six rollers 26 are rotatably installed in the interior of the nut 13. Mounting posts 28 are fixedly installed at both ends of the six rollers 26, and the mounting posts 28 are movably installed in the mounting holes 27. The angle encoder 10 is installed on the outer side of the rotating shaft 11. A mounting disc 19 is fixedly installed on one side of the nut 13. The six-axis force sensor 14 is installed on one side of the mounting disc 19. A frameless torque motor 9 is fixedly installed on the outer side of the end of the rotating shaft 11 away from the lead screw 12. A bearing seat 15 is installed at the end of the lead screw 12 away from the rotating shaft 11. The lead screw 12 is movably installed inside the nut 13, and the outer sides of the rollers 26 are meshed with the outer side of the lead screw 12. Internal gear rings 30 are installed on both sides of the inner cavity of the nut 13. Rotating gears 29 are fixedly installed on the outer sides of the mounting posts 28 at both ends of the six rollers 26. The outer sides of the connecting bars 20 are meshed with the inner sides of the internal gear rings 30. Retaining rings 25 are clamped and installed inside both ends of the nut 13.

[0026] Working principle of the above technical solution: After the frameless torque motor 9 is started, it can drive the rotating shaft 11 to rotate through the rotor, thereby driving the lead screw 12 to rotate. When the lead screw 12 rotates, it can drive the six rollers 26 inside the nut 13 to rotate, thereby driving the mounting column 28 to rotate inside the mounting hole 27 and driving the rotating gear 29 to rotate, thereby driving the internal gear ring 30 to rotate. And under the limitation of the support and limit assembly, the nut 13 moves linearly outside the lead screw 12, so that the linear joint of the humanoid robot operates, realizing movements such as joint extension and contraction. Using a planetary roller screw for linear motion at the joint can ensure the smoothness of the joint, and can bear large axial loads and radial loads. At the same time, it has the characteristics of high precision, high stiffness and long life. In addition, the multi-line contact between the rollers 26 and the lead screw 12 and the nut 13 makes the transmission more stable, reducing vibration and noise. The cooperation of the angle encoder 10 and the scale base 22 can calculate the linear operation accuracy of the joint. The angle encoder 10 is installed on the rotating shaft 11 and can real-time measure the rotation angle of the rotating shaft 11 and convert it into an electrical signal for output. The scale base 22 is installed in the movement direction of the nut 13 and is used to accurately measure the linear displacement of the nut 13. The calculation formula is: Linear motion accuracy = Angle encoder value * Pitch - Scale base value. When the linear motion accuracy exceeds the set range, the control system can timely adjust the output of the frameless torque motor 9 to compensate the transmission system, thereby ensuring the linear motion accuracy of the joint. In addition, the six-axis force sensor 14 can detect the forces in all aspects during joint operation, and can real-time detect the six-direction forces and torques received by the joint during operation, including the forces in three orthogonal directions and the torques in three orthogonal directions. By analyzing the data collected by the six-axis force sensor 14, the force conditions of the joint in different motion states can be understood, providing an important basis for the motion control, force control and safety protection of the robot.

[0027] In another embodiment, as Figures 1-7 shown, the support and limit assembly includes a mounting top plate 18. Fixed vertical plates 7 are fixedly installed at the bottoms of both ends of the two moving joints 2 of the mounting top plate 18. Two slide bar grooves 23 are symmetrically formed at the bottom of the mounting top plate 18. Limiting slide bars 16 are slidably installed inside the two slide bar grooves 23. One ends of the two fixed vertical plates 7 away from the mounting top plate 18 are respectively fixedly connected to the outer sides of the frameless torque motor 9 and the bearing seat 15. One end of the limiting slide bar 16 away from the planet carrier 24 is fixedly connected to the top of the mounting seat 8. The scale base 22 is fixedly installed at the bottom of the mounting top plate 18, and the position of the grating scale 21 corresponds to the position of the reading head 17.

[0028] The ruler base 22 and the grating ruler 21 can be fixed in place through the provided mounting top plate 18. Additionally, the frameless torque motor 9 and the bearing block 15 can be fixed through the provided fixed vertical plate 7. Moreover, the movement of the nut 13 can be limited by the cooperation between the provided limit slide bar 16 and the slide bar groove 23, enabling the nut 13 to move horizontally on the outside of the lead screw 12.

[0029] In another embodiment, as Figures 1-7 shown, a fixed joint 1 is fixedly installed at the top of the mounting top plate 18. A moving joint 2 is slidably installed on the outside of the fixed joint 1. One end of the moving joint 2 is fixedly installed with a connecting plate one 3. The moving end of the fixed joint 1 is fixedly installed with a connecting plate two 5. Two moving slide bars 6 are symmetrically and fixedly installed on the outside of the nut 13. Slide grooves 4 are formed on both sides of the fixed joint 1. The moving slide bars 6 are slidably installed inside the slide grooves 4, and the ends of the moving slide bars 6 away from the nut 13 are fixedly connected to the inside of the moving joint 2.

[0030] When the nut 13 moves on the outside of the lead screw 12, it can drive the moving joint 2 to move on the outside of the fixed joint 1 through the moving slide bars 6, thereby realizing linear movement at the joint, and can be connected to the other components of the robot through the connecting plate one 3 and the connecting plate two 5.

[0031] Working principle: After the frameless torque motor 9 starts, it can drive the rotating shaft 11 to rotate through the rotor, thereby driving the lead screw 12 to rotate. When the lead screw 12 rotates, it can drive the six rollers 26 inside the nut 13 to rotate, thereby driving the mounting post 28 to rotate inside the mounting hole 27 and driving the rotating gear 29 to rotate, thereby driving the internal gear ring 30 to rotate. And under the limitation of the support and limit component, the nut 13 moves linearly outside the lead screw 12, so that the linear joint of the humanoid robot operates, realizing the movement such as the extension and contraction of the joint. Using the planetary roller screw for the linear motion at the joint can ensure the smoothness of the joint, and can bear large axial loads and radial loads, and at the same time has the characteristics of high precision, high stiffness and long life. In addition, the multi-line contact between the rollers 26 and the lead screw 12 and the nut 13 makes the transmission more stable, reducing vibration and noise. The scale base 22 and the grating scale 21 can be fixed in place by the provided mounting top plate 18. In addition, the frameless torque motor 9 and the bearing seat 15 can be fixed by the provided fixed vertical plate 7. When the nut 13 moves outside the lead screw 12, it can drive the moving joint 2 to move outside the fixed joint 1 through the moving slide bar 6, thereby realizing the linear movement at the joint, and can be connected to the other components of the robot through the connecting plate one 3 and the connecting plate two 5. In addition, the cooperation between the provided limit slide bar 16 and the slide bar groove 23 can limit the movement of the nut 13, making the nut 13 move horizontally outside the lead screw 12. The cooperation between the provided angle encoder 10 and the scale base 22 can calculate the linear operation accuracy of the joint. The angle encoder 10 is installed on the rotating shaft 11 and can measure the rotation angle of the rotating shaft 11 in real time and convert it into an electrical signal for output. The scale base 2 is installed in the moving direction of the nut 13 and is used to accurately measure the linear displacement of the nut 13. The calculation formula is: linear motion accuracy = angle encoder value * pitch - scale base value. When the linear motion accuracy exceeds the set range, the control system can timely adjust the output of the frameless torque motor 9 to compensate the transmission system, thereby ensuring the linear motion accuracy of the joint. In addition, the six-axis force sensor 14 can detect the forces in all aspects during the operation of the joint, and can detect the forces and torques in six directions during the operation of the joint in real time, including the forces in three orthogonal directions and the torques in three orthogonal directions. By analyzing the data collected by the six-axis force sensor 14, the force conditions of the joint in different motion states can be understood, providing an important basis for the motion control, force control and safety protection of the robot.

[0032] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A linear joint of a humanoid robot, comprising a planetary roller screw, characterized in that: An angle encoder (10) is installed outside the planetary roller screw. A six-axis force sensor (14) is fixedly installed on one side of the planetary roller screw. A mounting seat (8) is fixedly installed outside the planetary roller screw. A reading head (17) is fixedly installed on the top of the mounting seat (8). A support and limit component is installed on the top of the mounting seat (8), and a scale base (22) is fixedly installed at the bottom of the support and limit component. A grating scale (21) is fixedly installed at the bottom of the scale base (22).

2. The linear joint of a humanoid robot according to claim 1, characterized in that: The planetary roller screw includes a lead screw (12) and a nut (13). A rotating shaft (11) is fixedly installed at one end of the lead screw (12). Planet carriers (24) are clamped and installed on both sides of the inner cavity of the nut (13). Six mounting holes (27) are respectively formed inside the planet carriers (24). Six rollers (26) are rotatably installed inside the nut (13). Mounting columns (28) are fixedly installed at both ends of the six rollers (26), and the mounting columns (28) are movably installed inside the mounting holes (27).

3. The linear joint of a humanoid robot according to claim 2, characterized in that: The angle encoder (10) is installed outside the rotating shaft (11). A mounting disc (19) is fixedly installed on one side of the nut (13). The six-axis force sensor (14) is installed on one side of the mounting disc (19).

4. The linear joint of a humanoid robot according to claim 3, characterized in that: A frameless torque motor (9) is fixedly installed outside the end of the rotating shaft (11) away from the lead screw (12). A bearing seat (15) is installed at the end of the lead screw (12) away from the rotating shaft (11). A connecting bar (20) is fixedly installed on one side of the frameless torque motor (9), and the end of the connecting bar (20) away from the frameless torque motor (9) is fixedly connected to one side of the angle encoder (10).

5. The linear joint of a humanoid robot according to claim 4, characterized in that: The lead screw (12) is movably installed inside the nut (13), and the outside of the roller (26) meshes with the outside of the lead screw (12).

6. The linear joint of a humanoid robot according to claim 5, characterized in that: Inner gear rings (30) are installed on both sides of the inner cavity of the nut (13). Rotating gears (29) are fixedly installed on the outside of the mounting columns (28) at both ends of the six rollers (26). The outside of the connecting bar (20) meshes with the inside of the inner gear rings (30). Retaining rings (25) are clamped and installed inside both ends of the nut (13).

7. The linear joint of a humanoid robot according to claim 6, characterized in that: The support and limit component includes a mounting top plate (18). Fixed vertical plates (7) are fixedly installed at the bottoms of both ends of the mounting top plate (18). Two slide bar grooves (23) are symmetrically formed at the bottom of the mounting top plate (18). Limit slide bars (16) are slidably installed inside the two slide bar grooves (23).

8. A linear joint of a humanoid robot according to claim 7, characterized in that: The ends of the two fixed vertical plates (7) away from the mounting top plate (18) are respectively fixedly connected to the outside of the frameless torque motor (9) and the bearing seat (15). The ends of the limit slide bars (16) away from the planet carrier (24) are fixedly connected to the top of the mounting seat (8).

9. A linear joint of a humanoid robot according to claim 8, characterized in that: The scale base (22) is fixedly installed at the bottom of the mounting top plate (18). The position of the grating scale (21) corresponds to the position of the reading head (17).

10. The linear joint of a humanoid robot according to claim 9, characterized in that: A fixed joint (1) is fixedly installed at the top of the installation top plate (18). A moving joint (2) is slidably installed on the outer side of the fixed joint (1). One end of the moving joint (2) is fixedly installed with a first connecting plate (3). The moving end of the fixed joint (1) is fixedly installed with a second connecting plate (5). Two moving sliding rods (6) are symmetrically and fixedly installed on the outer side of the nut (13). Chute grooves (4) are formed on both sides of the fixed joint (1). The moving sliding rods (6) are slidably installed inside the chute grooves (4), and the ends of the moving sliding rods (6) far away from the nut (13) are fixedly connected to the inner side of the moving joint (2).

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