Three-degree-of-freedom series-parallel hybrid humanoid robot waist structure

Abstract

The invention discloses a three-degree-of-freedom series-parallel hybrid humanoid robot waist structure, and relates to the technical field of robots. The defects that an existing multi-degree-of-freedom waist structure is not compact enough, limited in precision, low in rigidity and poor in stability are overcome. The robot comprises a yaw joint mechanism and a pitching-sidesway joint mechanism which are connected in series, upper limbs and legs of the robot are connected through the yaw joint mechanism and the pitching-sidesway joint mechanism, and the yaw joint mechanism can drive the upper limbs of the robot to do yaw motion; the pitching-sidesway joint mechanism comprises a movable platform, a static platform, a joint universal joint and two joint driving assemblies, the movable platform is fixedly connected with the upper limbs of the robot, the static platform is fixedly connected with the legs of the robot, the joint universal joint is connected with the movable platform and the static platform, and the two joint driving assemblies are symmetrically arranged on the left side and the right side of the joint universal joint; and the two joint driving assemblies are connected with the movable platform and the static platform correspondingly, and when the two joint driving assemblies drive the movable platform, the movable platform can do pitching motion and / or side-sway motion around the joint universal joint.

Description

Technical Field

[0001] The invention relates to the technical field of robots, and in particular to a three-degree-of-freedom serial-parallel hybrid waist structure of a humanoid robot. Background Art

[0002] The waist structure of a humanoid robot is used to connect the leg structure and the upper limb structure. It has a significant positive effect on the overall flexibility, motion accuracy and carrying capacity of the robot, and is an important component of the humanoid robot. In the prior art, the waist structure of a humanoid robot with fewer degrees of freedom cannot meet the robot's more complex motion requirements, while the waist structure with more degrees of freedom mostly has the disadvantages of being not compact enough, limited in accuracy, low in rigidity and poor in stability, which greatly limits the robot's motion ability and thus restricts the development of humanoid robots. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure, which is a serial-parallel hybrid structure, which can improve the compactness and degree of freedom of the waist structure, and can also improve the accuracy and rigidity of the waist structure.

[0004] In order to solve the above technical problems, a three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure of the present invention includes a yaw joint mechanism and a pitch-roll joint mechanism connected in series. The robot upper limb structure is connected to the robot leg structure via the yaw joint mechanism and the pitch-roll joint mechanism connected in series. The yaw joint mechanism can drive the robot upper limb structure to perform yaw movement; the pitch-roll joint mechanism includes a moving platform, a static platform, a joint universal joint and two groups of joint drive components. The moving platform is fixedly connected to the robot upper limb structure, the static platform is connected to the yaw joint mechanism, the joint universal joint connects the moving platform and the static platform so that the moving platform and the static platform can move relative to each other. The two groups of joint drive components are symmetrically arranged on the left and right sides of the joint universal joint and are respectively connected to the moving platform and the static platform. When the two groups of joint drive components drive the moving platform, the moving platform can be made to perform pitch movement and / or roll movement around the joint universal joint.

[0005] As an improvement of the present invention, the joint universal joint includes a pitch axis, a pitch sleeve, a roll axis and a roll sleeve, the pitch axis is vertically arranged and fixedly connected to the roll axis, the pitch sleeve is sleeved outside the pitch axis and can rotate around the pitch sleeve, the pitch sleeve is fixedly connected to the moving platform, the roll sleeve is sleeved outside the roll axis and can rotate around the roll axis, and the roll sleeve is fixedly connected to the static platform. The pitch sleeve and the pitch axis, as well as the roll sleeve and the roll axis are connected via two angular contact ball bearings installed back to back.

[0006] As an improvement of the present invention, two pitch angle limit blocks are provided at the end of the pitch shaft in the circumferential direction, and a limit swivel block is provided at the end of the pitch shaft sleeve, and the limit swivel block is located between the two pitch angle limit blocks to limit the pitch angle when the robot upper limb structure performs pitch motion. A roll angle limit block is provided on each side of the static platform and at the roll shaft to limit the roll angle when the robot upper limb structure performs roll motion.

[0007] As an improvement of the present invention, the joint drive assembly is a crank rocker drive assembly, which includes a joint drive motor, an output crank, an output connecting rod and a supporting shaft. The joint drive motor is installed on the lower side of the moving platform, and the joint drive motor can drive the output crank to rotate. The supporting shaft is parallel to the axis of the joint drive motor and installed on the upper side of the static platform. One end of the output connecting rod is movably connected to the output crank, and the other end is movably connected to the supporting shaft. The output connecting rod and the output crank, as well as the output connecting rod and the supporting shaft are connected via fisheye ball bearings.

[0008] As an improvement of the present invention, the yaw joint mechanism includes a mounting base, a cross roller bearing and a yaw motor, the mounting base is fixedly connected to the robot leg structure, the mounting base is connected to the static platform via a cross roller bearing, the yaw motor is mounted on the mounting base, and the yaw motor can drive the static platform to rotate so that the robot upper limb structure performs yaw motion. The mounting base is provided with a yaw angle limit block to limit the yaw angle when the robot upper limb structure performs yaw motion.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] 1. The waist structure of the humanoid robot of the present invention is composed of a yaw joint mechanism and a pitch-roll joint mechanism connected in series, and the pitch-roll joint mechanism adopts a parallel design. This series-parallel hybrid configuration design takes into account the advantages of the series mechanism and the parallel mechanism. The series mechanism provides a larger yaw motion range for the waist, and the parallel mechanism provides a higher motion accuracy for the waist. By optimizing the topological structure of the series and parallel parts, the waist structure not only maintains the necessary degrees of freedom, but also effectively reduces the volume of the waist structure, and the structure is more compact, so that efficient motion output can be achieved in a limited space, which significantly improves the space utilization of the waist structure.

[0011] 2. The pitch-roll joint mechanism of the present invention realizes two-degree-of-freedom motion under the joint action of two joint drive components and the constraint of the joint universal joint, wherein the joint universal joint is a constraint branch chain, and the two groups of joint drive components are the main transmission branch chains, that is to say, the moving platform and the static platform in the pitch-roll joint mechanism are connected by three branches arranged side by side, and the motion of each branch chain is mutually constrained, and the motion errors of each branch chain are also mutually constrained, so the cumulative error of the motion of each branch chain is small, and the moving platform will have a higher motion accuracy. In addition, the pitch-roll joint mechanism is a closed-loop parallel mechanism. When the pitch-roll joint mechanism is working, the external load is transferred to each branch chain, and each branch chain shares it, reducing the stress on a single branch chain, avoiding the problem of overload and deformation of a single branch chain, so that the pitch-roll joint mechanism has higher rigidity and load-bearing capacity.

[0012] 3. The joint drive assembly of the present invention adopts a crank rocker design, and the joint drive motor is arranged on a moving platform, so that the robot's upper limb structure and the waist structure are more compact as a whole, and the joint universal joint can be placed in a lower position. When the robot's upper limb structure pitches and swings sideways, the joint drive motor pitches and swings sideways together, so that the robot's upper limb structure and the joint drive motor will not interfere or collide, so that the waist structure obtains a larger range of motion, thereby bringing a larger range of motion to the entire robot's upper limbs, and the waist structure swinging along with the robot's upper limbs will be more anthropomorphic, and the shape will also be more anthropomorphic.

[0013] 4. In the yaw joint mechanism of the present invention, the mounting base and the static platform are connected via a cross roller bearing, so that all the weight of the upper limbs of the humanoid robot is ultimately transferred to the mounting base instead of to the yaw motor, thereby reducing the load and technical requirements borne by the yaw motor, and further improving the bearing capacity of the waist structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are incorporated as part of this application and are used to provide a further understanding of the present invention.

[0015] Figure 1 The present invention is a three-dimensional structural schematic diagram of a three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure.

[0016] Figure 2 This is a schematic diagram of the state of the waist structure of the humanoid robot of the present invention before side swing.

[0017] Figure 3 It is a schematic diagram of the state of the waist structure of the humanoid robot of the present invention after side swing.

[0018] Figure 4 It is a schematic diagram of the state of the waist structure of the humanoid robot of the present invention before pitching.

[0019] Figure 5 It is a schematic diagram of the state of the waist structure of the humanoid robot after pitching.

[0020] Figure 6 It is a schematic diagram of the state of the waist structure of the humanoid robot after yaw of the present invention.

[0021] Figure 7 It is a three-dimensional structural schematic diagram of the waist structure of the humanoid robot of the present invention.

[0022] Figure 8 The figure is a schematic diagram of the internal structure of the waist structure of the humanoid robot of the present invention.

[0023] Description of reference numerals:

[0024] 1- yaw joint mechanism, 11- mounting base, 12- cross roller bearing, 13- yaw motor;

[0025] 2-pitch-roll joint mechanism, 21-moving platform, 211-annular mounting seat, 22-static platform, 23-joint universal joint, 231-pitch shaft, 232-pitch shaft sleeve, 233-roll shaft, 234-roll shaft sleeve, 235-pitch angle limit block, 236-limiting shaft, 237-roll angle limit block, 238-yaw angle limit block, 24-joint drive assembly, 241-joint drive motor, 242-output crank, 243-output connecting rod, 244-support shaft. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with specific embodiments.

[0027] Figure 1 FIG. 1 shows a three-dimensional structural diagram of a three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure of the present invention, as shown in FIG. Figure 1 As shown, the waist structure of the humanoid robot includes a yaw joint mechanism 1 and a pitch-roll joint mechanism 2 connected in series, and the robot upper limb structure is connected to the robot leg structure via the yaw joint mechanism 1 and the pitch-roll joint mechanism 2 connected in series. The yaw joint mechanism 1 can drive the robot upper limb structure to perform yaw movement, and the pitch-roll joint mechanism 2 can drive the robot upper limb structure to perform pitch movement and / or roll movement. In other words, the waist structure has three degrees of freedom of yaw, pitch and roll, which increases the flexibility of the entire humanoid robot and meets the more complex movement requirements of the humanoid robot.

[0028] like Figure 7As shown, the pitch-roll joint mechanism 2 adopts a 2RSS-U parallel mechanism, which specifically includes a moving platform 21, a stationary platform 22, a joint universal joint 23 and two groups of joint drive components 24. The moving platform 21 is fixedly connected to the upper limb structure of the robot, and the stationary platform 22 is fixedly connected to the leg structure of the robot. The joint universal joint 23 connects the moving platform 21 and the stationary platform 22 so that the moving platform 21 and the stationary platform 22 can move relatively. The two groups of joint drive components 24 are symmetrically arranged on the left and right sides of the joint universal joint 23, and are respectively connected to the moving platform 21 and the stationary platform 22. When the two groups of joint drive components 24 drive the moving platform 21, the moving platform 21 can be made to perform pitch motion and / or roll motion around the joint universal joint 23. Specifically, Figure 2 and Figure 3 FIG. 4 shows a schematic diagram of the state of the waist structure of the humanoid robot before and after the side swing. Figure 2 and Figure 3 As shown, when the two sets of joint drive components 24 synchronously and reversely drive the moving platform 21, the left and right sides of the moving platform 21 are subjected to two eccentric forces of equal magnitude and opposite directions with the joint universal joint 23 as the center line. Under the combined force of the two eccentric forces and the constraint of the joint universal joint 23, the moving platform 21 drives the robot's upper limb structure to flip sideways to realize the lateral swing movement of the robot's upper limb structure. Figure 4 and Figure 5 Schematic diagram of the state of the waist structure of the humanoid robot before and after pitching is shown. Figure 4 and Figure 5As shown, when the two sets of joint drive components 24 drive the moving platform 21 synchronously and in the same direction, the left and right sides of the moving platform 21 are subjected to two eccentric forces of the same magnitude and direction with the joint universal joint 23 as the center line. Under the combined force of the two eccentric forces and the constraint of the joint universal joint 23, the moving platform 21 drives the robot upper limb structure to flip forward to achieve the pitching motion of the robot upper limb structure. When the two sets of joint drive components 24 drive the moving platform 21 synchronously and in the opposite direction, the left and right sides of the moving platform 21 are subjected to two eccentric forces of different magnitude and opposite directions with the joint universal joint 23 as the center line. Under the coupling force of the two eccentric forces and the constraint of the joint universal joint 23, the moving platform 21 drives the robot upper limb structure to perform the coupled motion of pitching and swaying. It can be seen that the pitch-roll joint mechanism 2 realizes the two-degree-of-freedom motion under the joint action of the two joint drive components 24 and the constraint of the joint universal joint 23, wherein the joint universal joint 23 is a constraint branch chain, and the two sets of joint drive components 24 are main transmission branches, that is to say, the moving platform 21 and the static platform 22 in the pitch-roll joint mechanism 2 are connected by three branches arranged side by side, and the motion of each branch chain is mutually constrained, and the motion errors of each branch chain are also mutually constrained, so the cumulative error of the motion of each branch chain is small, and the moving platform 21 will have a higher motion accuracy. In addition, the pitch-roll joint mechanism 2 is a closed-loop parallel mechanism. When the pitch-roll joint mechanism 2 is working, the external load is transferred to each branch chain, and each branch chain shares it, reducing the stress on a single branch chain, avoiding the problem of overload and deformation of a single branch chain, so that the pitch-roll joint mechanism 2 has higher rigidity and load-bearing capacity. Furthermore, since the yaw joint mechanism 1 and the pitch-roll joint mechanism 2 of the waist structure of the humanoid robot are designed in series, and the pitch-roll joint mechanism 2 is designed in parallel, this series-parallel hybrid configuration design takes into account the advantages of the series mechanism and the parallel mechanism. The series mechanism provides a larger yaw motion range for the waist, and the parallel mechanism provides a higher motion accuracy for the waist, and the kinematic solution is simple, which facilitates subsequent high-precision control. By optimizing the topological structure of the series and parallel parts, the waist structure not only maintains the necessary degrees of freedom, but also effectively reduces the volume of the waist structure, and the structure is more compact, so that efficient motion output can be achieved in a limited space, which significantly improves the space utilization of the waist structure.

[0029] Figure 6 The structure diagram of the joint universal joint 23 is shown in FIG. Figure 6As shown, the joint universal joint 23 of this embodiment is a two-degree-of-freedom universal joint, specifically including a pitch rotation axis 231, a pitch shaft sleeve 232, a roll rotation axis 233 and a roll shaft sleeve 234. The pitch rotation axis 231 and the roll rotation axis 233 are arranged vertically and fixedly connected. The pitch shaft sleeve 232 is sleeved outside the pitch rotation axis 231 and connected via two angular contact ball bearings installed back to back, so that the pitch shaft sleeve 232 can rotate around the pitch shaft sleeve 232, and the pitch shaft sleeve 232 is fixedly connected to the moving platform 21. The roll shaft sleeve 234 is sleeved outside the roll rotation axis 233 and connected via two angular contact ball bearings installed back to back, so that the roll shaft sleeve 234 can rotate around the roll rotation axis 233, and the roll shaft sleeve 234 is fixedly connected to the static platform 22. Since the joint universal joint 23 is the main load-bearing component of the waist structure, the use of two angular contact ball bearings installed back to back to support the side swing shaft sleeve 234 or the pitch shaft sleeve 232 can enhance the anti-interference ability of the joint universal joint 23 to external forces and a higher overturning moment during the load-bearing process, further improving the rigidity and load-bearing capacity of the system. Figure 2 and Figure 3 As shown, the ends of the pitch axis 231 and the roll axis 233 are both provided with dials, and the ends of the pitch shaft sleeve 232 and the roll axis sleeve 234 are both provided with scale pointing lines. Such a design makes it easy to align the zero position during installation, and when the pitch shaft sleeve 232 and the pitch axis 231 rotate relative to each other, the pitch angle of the waist can be determined through the dial on the pitch axis 231 and the scale pointing line on the pitch shaft sleeve 232, or when the roll axis sleeve 234 and the roll axis 233 rotate relative to each other, the roll angle of the waist can be determined through the dial on the roll axis 233 and the scale pointing line on the roll shaft sleeve 234.

[0030] In order to avoid the robot's upper limb structure from colliding or interfering with other parts when the waist structure is doing pitch and sway movements, such as Figure 5 As shown, the end of the pitch shaft 231 of this embodiment is provided with two pitch angle limit blocks 235 along the circumferential direction, and the end of the pitch shaft sleeve 232 is provided with a limit rotation block 236, and the limit rotation block 236 is located between the two pitch angle limit blocks 235. When the pitch shaft sleeve 232 rotates around the pitch shaft 231 by a certain angle, the limit rotation block 236 abuts against the side wall of the pitch angle limit block 235, so that the pitch shaft sleeve 232 cannot continue to rotate, thereby achieving the pitch angle limit and preventing the robot upper limb structure from colliding or interfering with other components when performing pitch motion. Figure 8As shown, a side swing angle limit block 237 is provided on the static platform 22 of the present embodiment and on both sides of the side swing shaft 233. When the side swing shaft 233 rotates a certain angle in the side swing shaft sleeve 234, the position of the pitch shaft sleeve 232 close to the edge abuts against the side swing angle limit block 237, so that the side swing shaft 233 cannot continue to rotate, thereby limiting the side swing angle and preventing the robot's upper limb structure from colliding or interfering with other components when performing a side swing movement.

[0031] Figure 4 The structure diagram of the joint drive assembly 24 is shown as follows: Figure 4 As shown, the joint drive assembly 24 of this embodiment is a crank rocker drive assembly, which includes a joint drive motor 241, an output crank 242, an output connecting rod 243 and a support shaft 244. Figure 3As shown, an annular mounting seat 211 is provided on the lower side of the moving platform 21, and the annular mounting seat 211 is fixedly connected to the pitch shaft sleeve 232 of the joint universal joint 23. The joint driving motors 241 in the two joint driving assemblies 24 are coaxially installed side by side in the annular mounting seat 211, that is, the two joint driving motors 241 are installed on the moving platform 21, the motor shaft of the joint driving motor 241 is connected to the output crank 242 and can drive the output crank 242 to rotate, the support shaft 244 is parallel to the motor shaft of the joint driving motor 241 and is installed on the upper side of the static platform 22, one end of the output connecting rod 243 is movably connected to the output crank 242 via a fisheye ball bearing, and the other end is movably connected to the support shaft 244 via a fisheye ball bearing. When the motor shaft of the joint drive motor 241 drives the output crank 242 to rotate, the output crank 242 generates a pulling force or a thrust force on the output connecting rod 243. Since the other end of the output connecting rod 243 is installed on the static platform 22, the output connecting rod 243 transmits the pulling force or the thrust force received to the output crank 242 and the joint drive motor 241 in reverse. The two joint drive motors 241 drive the dynamic platform 21 to do pitch or roll motion, thereby realizing the pitch motion, roll motion or pitch and roll coupled motion of the robot upper limb structure. The joint drive assembly 24 of this embodiment can also be in the form of a linear electric cylinder, but the 2SPS-U parallel mechanism using the linear electric cylinder as the pitch-roll joint mechanism 2 occupies a large space, lacks movement flexibility, requires higher installation accuracy of the linear electric cylinder, and due to the limited stroke of the linear electric cylinder, the pitch motion and roll motion range of the waist structure are limited. In contrast, the joint drive assembly 24 adopts a crank rocker design as the 2RSS-U parallel mechanism of the pitch-roll joint mechanism 2, and the joint drive motor 241 is arranged on the moving platform 21, so that the robot's upper limb structure and the waist structure are more compact as a whole, and the joint universal joint 23 can be placed in a lower position. When the robot's upper limb structure pitches and swings sideways, the joint drive motor 241 pitches and swings sideways together, so that the robot's upper limb structure and the joint drive motor 241 will not interfere or collide, so that the waist structure has a larger range of motion, thereby bringing a larger range of motion to the entire robot's upper limb, and the movement of the waist structure swinging along with the robot's upper limb will be more anthropomorphic, and the shape will also be more anthropomorphic. If the joint drive motor 241 is installed on the static platform 22 and the other end of the output connecting rod 243 is connected to the dynamic platform 21, the position of the joint universal joint 23 will be too high, and the volume of the connecting part between the waist structure and the leg structure of the robot will be larger. When the upper limb structure of the robot is pitching or swinging, it is easy to interfere with the joint drive motor 241 or affect the motion range of the output crank 242, that is, the motion range of the upper limb of the robot will be reduced and the trunk movement will be too stiff.Therefore, the joint drive assembly 24 of this embodiment adopts a crank rocker design, which makes the robot's upper limb structure more flexible, has a larger range of motion and a more compact structure, so that it can better cooperate with the movement of the robot's leg structure and upper limb structure. In addition, the joint drive motor 241 has a stronger anti-interference ability. Therefore, the use of two crank rocker drive assemblies as a 2RSS-U parallel mechanism is more suitable for the design requirements of the waist. It should also be noted that the output connecting rod 243 and the output crank 242, as well as the output connecting rod 243 and the support shaft 244 are all movably connected via fisheye ball bearings. The use of fisheye ball bearings can withstand higher loads and increase the carrying capacity of the main transmission branch chain.

[0032] Figure 7 The structure of the yaw joint mechanism 1 is shown in FIG. Figure 7 As shown, the yaw joint mechanism 1 of this embodiment includes a mounting base 11, a cross roller bearing 12 and a yaw motor 13. The mounting base 11 is fixedly connected to the robot leg structure. The mounting base 11 is connected to the static platform 22 via the cross roller bearing 12 so that the mounting base 11 and the static platform 22 can rotate relative to each other. The housing of the yaw motor 13 is mounted on the mounting base 11. The motor shaft of the yaw motor 13 passes through the cross roller bearing 12 and is connected to the static platform 22. When the yaw motor 13 drives the static platform 22 to rotate, the static platform 22 drives the robot upper limb structure to rotate via the joint universal joint 23 and the moving platform 21, thereby realizing the yaw movement of the robot upper limb structure. Figure 8 As shown, when the waist structure bears the load brought by the robot's upper limbs and trunk, the load is transmitted from the moving platform 21 to the joint universal joint 23, and then transmitted to the static platform 22 via the joint universal joint 23. The static platform 22 transmits the bearing load to the mounting base 11 through the cross roller bearing 12. Such a design allows all the weight of the humanoid robot's upper limbs to be ultimately transmitted to the mounting base 11, rather than to the yaw motor 13, thereby reducing the load and technical requirements borne by the yaw motor 13, and further improving the bearing capacity of the waist structure. In addition, the cross roller bearing 12 has high radial and axial stiffness. The static platform 22 is supported by the cross roller bearing 12, which can prevent the cross roller shaft from deforming when bearing a large load, thereby reducing the load of the yaw motor 13, allowing the yaw motor 13 to maintain high-precision rotation, reducing the yaw gap and deformation, and thus ensuring the stability and accuracy of the movement.

[0033] In order to prevent the robot's upper limb structure from colliding or interfering with other components due to excessive rotation angle when the waist structure makes yaw motion, a yaw angle limit block 238 is provided on the mounting base 11 of this embodiment. When the yaw motor 13 drives the static platform 22 to rotate a certain angle, the supporting shaft 244 on the static platform 22 abuts against the yaw angle limit block 238, so that the static platform 22 cannot continue to rotate, thereby achieving yaw angle limitation and preventing the robot's upper limb structure from colliding or interfering with other components when making yaw motion.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure, characterized in that: It includes a yaw joint mechanism and a pitch-roll joint mechanism connected in series, wherein the robot upper limb structure is connected to the robot leg structure via the yaw joint mechanism and the pitch-roll joint mechanism connected in series, and the yaw joint mechanism can drive the robot upper limb structure to perform yaw motion; The pitch-roll joint mechanism comprises a moving platform, a stationary platform, a joint universal joint and two groups of joint drive components. The moving platform is fixedly connected to the upper limb structure of the robot, the stationary platform is connected to the yaw joint mechanism, the joint universal joint connects the moving platform and the stationary platform so that the moving platform and the stationary platform can move relatively. The two groups of joint drive components are symmetrically arranged on the left and right sides of the joint universal joint and are respectively connected to the moving platform and the stationary platform. When the two groups of joint drive components drive the moving platform, the moving platform can perform pitch motion and / or roll motion around the joint universal joint.

2. A three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 1, characterized in that: The joint universal joint includes a pitch axis, a pitch shaft sleeve, a roll axis and a roll shaft sleeve. The pitch axis is vertically arranged and fixedly connected to the roll axis. The pitch shaft sleeve is sleeved outside the pitch axis and can rotate around the pitch shaft sleeve. The pitch shaft sleeve is fixedly connected to the moving platform. The roll axis sleeve is sleeved outside the roll axis and can rotate around the roll axis. The roll shaft sleeve is fixedly connected to the static platform.

3. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 2, characterized in that: The pitch shaft sleeve and the pitch rotation axis as well as the roll shaft sleeve and the roll rotation axis are connected via two angular contact ball bearings installed back to back.

4. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 2, characterized in that: The end of the pitch shaft is provided with two pitch angle limit blocks along the circumferential direction, and the end of the pitch shaft sleeve is provided with a limit rotation block, which is located between the two pitch angle limit blocks to limit the pitch angle when the robot upper limb structure performs pitch motion.

5. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 2, characterized in that: A side swing angle limiting block is respectively arranged on the static platform and on both sides of the side swing rotating shaft, so as to limit the side swing angle when the robot upper limb structure performs side swing motion.

6. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 1, characterized in that: The joint drive assembly is a crank rocker drive assembly, which includes a joint drive motor, an output crank, an output connecting rod and a supporting shaft. The joint drive motor is installed on the lower side of the moving platform. The joint drive motor can drive the output crank to rotate. The supporting shaft is parallel to the axis of the joint drive motor and installed on the upper side of the static platform. One end of the output connecting rod is movably connected to the output crank, and the other end is movably connected to the supporting shaft.

7. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 6, characterized in that: An annular mounting seat is arranged on the lower side of the moving platform, and two joint driving motors are coaxially mounted side by side in the annular mounting seat.

8. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 6, characterized in that: The output connecting rod and the output crank as well as the output connecting rod and the supporting rotating shaft are connected via fisheye ball bearings.

9. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 1, characterized in that: The yaw joint mechanism includes a mounting base, a cross roller bearing and a yaw motor. The mounting base is fixedly connected to the robot leg structure, and the mounting base is connected to the static platform via a cross roller bearing. The yaw motor is installed on the mounting base, and the yaw motor can drive the static platform to rotate so that the robot upper limb structure performs yaw movement.

10. The three-degree-of-freedom serial-parallel hybrid humanoid robot waist structure according to claim 9, characterized in that: The mounting base is provided with a yaw angle limit block to limit the yaw angle when the robot upper limb structure performs yaw motion.

Images