A bionic robot neck joint mechanism based on four-branch parallel structure

Abstract

The application discloses a kind of four branched chain parallel structure-based bionic robot neck joint mechanism, including static platform, dynamic platform, the static platform, dynamic platform between being provided with by two SPR branch chain composition SPR branch chain group and by two SPU branch chain composition SPU branch chain group, the SPR branch chain is constraint branch chain, dynamic platform under the action of two SPR branch chain, two SPU branch chain, relative to static platform output includes three rotational degrees of freedom and one translational degree of freedom four degrees of freedom space movement.The bionic motion ability of the application is strong, adopts 2SPR-2SPU parallel topology configuration, can realize three rotational degrees of freedom, namely, pitch, lateral swing and so on, and one translational degree of freedom, namely, vertical stretch, effectively simulate the flexible posture of biological neck, satisfy the head movement demand of bionic robot.The dynamic platform of the application, static platform adopts staggered trapezoidal hinge point layout, optimizes the mechanical transmission performance, enhances the structural rigidity of mechanism.

Description

Technical Field

[0001] This invention belongs to the field of robot structure design and biomimetic mechanical technology, specifically relating to a biomimetic robot neck joint mechanism based on a four-branch parallel structure. Background Technology

[0002] With the rapid development of biomimetic robot technology, robots are increasingly being used in service, medical rehabilitation, social interaction, and human-robot collaboration. To achieve more natural human-robot interaction, robots need to have neck movement capabilities similar to those of the human body, including complex posture changes such as multi-degree-of-freedom rotation, pitch, and tilt. Currently, the neck joint structure of humanoid robots mostly uses a series of articulated motor modules to achieve multiple degrees of freedom of movement.

[0003] Compared to serial structures, parallel mechanisms have been widely used in industrial robots, precision manipulation platforms, and biomimetic structures in recent years due to their advantages such as compact structure, high rigidity, high precision, and strong load capacity. Parallel mechanisms support and drive the actuators through multiple independent branches, enabling multi-degree-of-freedom motion control while maintaining high stability.

[0004] Therefore, by introducing the principle of parallel mechanism into the design of biomimetic robot neck joint, the limitations of serial structure are overcome, and a biomimetic robot neck joint mechanism based on a four-branch parallel structure is proposed, providing a new technical approach for achieving high-performance and natural biomimetic neck movement. Summary of the Invention

[0005] To address the issues of insufficient flexibility, complex structure, or limited load-bearing capacity in existing bionic robot neck joint mechanisms, this invention provides a bionic robot neck joint mechanism based on a four-branch parallel structure. This mechanism can simulate the flexible posture of a biological neck and features a compact structure, smooth movement, and reliable connection.

[0006] The technical solution of this invention is: a biomimetic robot neck joint mechanism based on a four-branch parallel structure, including a static platform and a moving platform. Between the static platform and the moving platform, there is an SPR branch group consisting of two SPR branches and a branch group consisting of two SPU branches. The SPR branches are constraint branches. Under the action of the two SPR branches and the two SPU branches, the moving platform outputs a four-degree-of-freedom spatial motion relative to the static platform, which includes three rotational degrees of freedom and one translational degree of freedom. The two SPR branches are V-shaped, and the two SPU branches are inverted V-shaped. Both the SPR branches and the SPU branches include a combined ball joint component.

[0007] Furthermore, four mounting through holes are formed in the static platform. The four mounting through holes are arranged in a trapezoidal shape. The two closer mounting through holes in the upper base of the trapezoid form a near mounting hole group, and the farther mounting through holes in the lower base of the trapezoid form a far mounting hole group. The S end of the SPR branch is fixed in the near mounting hole group, and the S end of the SPU branch is fixed in the far mounting hole group.

[0008] Furthermore, the moving platform forms four hinge positions, which are arranged in a trapezoidal shape. The two closer hinge positions in the upper base of the trapezoid are called near hinge positions, and the two farther hinge positions in the lower base of the trapezoid are called far hinge positions. The R end of the SPR branch is fixed in the far hinge position, and the U end of the SPU branch is fixed in the near hinge position.

[0009] Furthermore, the spherical rotation output end of the combined ball joint component in the SPU branch is connected to the motor support frame, and an integrated linear motor module serving as a linear joint is installed in the motor support frame. The push rod of the integrated linear motor module is connected to the Hooke joint.

[0010] Furthermore, the spherical rotation output end of the combined ball joint component in the SPR branch is connected to the push rod of the integrated linear motor module, and the body of the integrated linear motor module and the moving platform form a rotating pair.

[0011] Furthermore, the combined ball joint assembly includes a Hooke's joint and a deep groove ball bearing. The outer ring of the deep groove ball bearing mates with the end face of the stationary platform, and the inner ring is fixed to the shaft by an elastic retaining ring. A through hole is formed on the other side of the shaft, and the through hole is aligned with the positioning hole of the Hooke's joint to achieve the connection between the two.

[0012] Furthermore, the rotating pair includes an octagonal connector at the end of the integrated linear motor module body, and the octagonal connector is connected to the rotating pair assembly via a shouldered pin to form the rotating pair.

[0013] Furthermore, the rotating pair connection assembly is fixed to the moving platform by means of a threaded connection.

[0014] The beneficial effects of this invention are as follows:

[0015] This invention has strong biomimetic motion capabilities. It adopts a 2SPR-2SPU parallel topology configuration, which can realize three rotational degrees of freedom, namely pitch and yaw, and one translational degree of freedom, namely vertical extension and contraction. It effectively simulates the flexible posture of a biological neck and meets the head movement requirements of biomimetic robots.

[0016] This invention features a large working space and high load-bearing capacity. The combined ball joint at the bottom of the branch chain adopts a combination design of Hooke's joint and deep groove ball bearing, which increases the range of joint swing angle and thus expands the working space, while effectively improving the load-bearing capacity of the mechanism.

[0017] This invention features a compact structure and direct drive, employing an integrated linear motor module as the direct drive chain, which simplifies the transmission chain, resulting in a more compact overall structure and faster response speed.

[0018] The present invention provides a stable and reliable connection. The connection between the static platform and the support chain adopts a stepped surface combined with an elastic retaining ring design, which achieves reliable axial locking and effectively prevents the support chain from detaching during high-speed and high-frequency robot movements, thereby improving the safety and stability of the system.

[0019] The present invention employs an alternating trapezoidal hinge point layout for the moving platform and the static platform, which optimizes the mechanical transmission performance and enhances the structural rigidity of the mechanism. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram showing the distribution of the static platform and its branch hinge positions in this invention;

[0022] Figure 3 This is a detailed structural diagram of the SPU branch chain in this invention;

[0023] Figure 4 This is a detailed schematic diagram of the SPR branch in this invention;

[0024] Figure 5 This is a schematic diagram showing the distribution of the moving platform and its branch hinge points in this invention;

[0025] Figure 6 This is a detailed structural diagram of the U-shaped connecting frame in this invention;

[0026] Figure 7 This is a diagram showing the state of the two SPR branches and two SPU branches after equal scaling in this invention.

[0027] Figure 8 This is a state diagram of the two SPR branches and two SPU branches after differential expansion and contraction in this invention.

[0028] The components include: 1. Static platform; 2. Moving platform; 3. SPR branch chain; 4. SPU branch chain; 5. Combined ball joint assembly; 6. Integrated linear motor module; 7. Hooke hinge; 8. Elastic retaining ring; 9. Motor support frame; 10. Rotary joint connection assembly; 11. Octagonal joint; 12. Shoulder pin; 13. U-joint connection frame; 14. Mounting through hole; 15. Push rod; 16. Threaded connecting rod; 17. Deep groove ball bearing. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0030] like Figures 1 to 8 As shown, a biomimetic robot neck joint mechanism based on a four-branch parallel structure includes a static platform 1 and a moving platform 2. An SPR branch group consisting of two SPR branches 3 and a branch group consisting of two SPU branches 4 are arranged between the static platform 1 and the moving platform 2. The SPR branches 3 are constraint branches. Under the action of the two SPR branches 3 and the two SPU branches 4, the moving platform 2 outputs a four-degree-of-freedom spatial motion relative to the static platform 1, which includes three rotational degrees of freedom and one translational degree of freedom.

[0031] The static platform 1 has four mounting through holes 14 arranged in a trapezoidal shape. The two mounting through holes 14 that are closer in the upper base of the trapezoid are called the near mounting hole group, and the mounting through holes 14 that are farther in the lower base of the trapezoid are called the far mounting hole group. The S end of the SPR branch 3 is fixed in the near mounting hole group, and the S end of the SPU branch 4 is fixed in the far mounting hole group.

[0032] The moving platform 2 has four hinge positions arranged in a trapezoidal shape. The two closer hinge positions in the upper base of the trapezoid are called near hinge positions, and the two farther hinge positions in the lower base of the trapezoid are called far hinge positions. The R end of the SPR branch 3 is fixed in the far hinge position, and the U end of the SPU branch 4 is fixed in the near hinge position.

[0033] Based on the distribution characteristics of human neck muscles, the branch structure is arranged biomimetously, wherein the two SPR branches 3 are arranged in a V-shape and the two SPU branches 4 are arranged in an inverted V-shape.

[0034] The SPU branch chain 4 includes a combined ball joint assembly 5. The spherical rotation output end of the combined ball joint assembly 5 is connected to the motor support frame 9. An integrated linear motor module 6, which serves as a linear joint, is installed in the motor support frame 9. The push rod 15 of the integrated linear motor module 6 is connected to the Hooke hinge 7.

[0035] The SPR branch 3 includes a combined ball joint assembly 5. The spherical rotation output end of the combined ball joint assembly 5 is connected to the push rod 15 of the integrated linear motor module 6. The body of the integrated linear motor module 6 and the moving platform 2 form a rotating pair.

[0036] The rotating pair includes an octagonal connector 11 at the end of the integrated linear motor module 6 body. The octagonal connector 11 forms a rotating pair with the rotating pair connection assembly 10 via a shoulder pin 12.

[0037] The rotating pair connection assembly 10 is fixed to the moving platform 2 by means of a threaded connection.

[0038] Specifically, both the SPR branch 3 and the SPU branch 4 are equipped with an integrated linear motor module 6, which serves as the power source for the branch.

[0039] More specifically, the integrated linear motor module 6 in the SPR branch 3 is installed in an inverted manner, which facilitates the connection of the rear interface of the integrated linear motor module 6 to the moving platform 2.

[0040] Specifically, a mounting through hole 14 is formed in the static platform 1, the outer ring of the deep groove ball bearing 17 of the combined ball joint assembly 5 abuts against the stepped surface in the mounting through hole 14, and an elastic retaining ring 8 is provided in the upper groove of the mounting through hole 14 for axial locking and limiting of the mounting through hole 14.

[0041] Specifically, the top of the SPR branch 3 is connected via a revolute joint connecting assembly 10, with the central axis of the revolute joint connecting assembly 10 forming a 30° angle with the central axis of the moving platform 2; the two revolute joint connecting assemblies 10 are symmetrically arranged about the central axis of the moving platform 2. This structural arrangement incorporates biomimetic design concepts and is comprehensively optimized based on the working space range and force characteristics of the parallel mechanism to determine the spatial layout of each branch node of the parallel mechanism.

[0042] like Figure 1 The diagram illustrates a detailed description of a biomimetic robot neck joint mechanism based on a four-branch parallel structure, comprising: a static platform 1, a dynamic platform 2, two SPR branches 3 located between the two, and two SPU branches 4.

[0043] Specifically, the static platform 1 serves as a base, rigidly connected to the torso of the humanoid robot, providing a support reference for the entire mechanism; the moving platform 2 is used to connect the robot's head load. By controlling the coordinated extension and retraction motion of the two SPR branches 3 and the two SPU branches 4, the moving platform 2 can output a four-degree-of-freedom spatial motion relative to the static platform 1, including three rotational degrees of freedom and one translational degree of freedom, thereby simulating the flexible posture of a biological neck.

[0044] like Figure 2 The diagram illustrates a detailed description of the four hinge points in the static platform 1, arranged in a trapezoidal shape. The hinge points of the two SPU branches 4 are located at the longer lower base of the trapezoid, while the hinge points of the two SPR branches 3 are located at the shorter upper base of the trapezoid.

[0045] The mounting through hole 14 is a stepped hole, the large-diameter section of which accommodates the deep groove ball bearing 17, and an elastic retaining ring 8 is provided in the groove on the end face of the mounting through hole 14. The elastic retaining ring 8 provides reliable axial locking and limiting for the deep groove ball bearing 17, thereby ensuring the stability of the connection between the support chain and the stationary platform 1 and effectively preventing the support chain from disengaging during high-speed and high-frequency motion.

[0046] like Figure 3The diagram is described in detail. The SPU branch 4, from bottom to top, includes a combined ball joint assembly 5, an integrated linear motor module 6, and a Hooke hinge 7.

[0047] To increase the working space and load-bearing capacity of the branch chain, the combined ball joint assembly 5 at the bottom of the SPU branch chain 4 adopts a combined design, consisting of a Hooke hinge 7 and a deep groove ball bearing 17. One end of the combined ball joint assembly 5 is connected to the stationary platform 1, and the other end is connected to the motor support frame 9. The integrated linear motor module 6, as the moving joint in the SPU branch chain 4, is fixedly installed on the motor support frame 9 by bolts, so that it can swing with the combined ball joint assembly 5 and achieve axial telescopic movement. The push rod 15 of the integrated linear motor module 6 has a threaded hole at its top end, which is connected to the Hooke hinge 7 at the end through a threaded connecting rod 16. The Hooke hinge 7 is coupled to the moving platform 2.

[0048] like Figure 4 To illustrate in detail, the SPR branch 3 includes a combined ball joint assembly 5 at the bottom, an integrated linear motor module 6 in the middle, and a rotating joint connection assembly 10 at the top.

[0049] As described above, the combined ball joint assembly 5 increases the range of joint swing angle. One end of the combined ball joint assembly 5 is connected to the stationary platform 1, and the other end is fastened to the threaded hole at the end of the push rod 15 of the integrated linear motor module 6 through a threaded connecting rod 16.

[0050] More specifically, the integrated linear motor module 6 of the SPR branch chain 3 is installed in an inverted manner, that is, the push rod 15 is at the bottom and connected to the stationary platform 1; the motor body is at the top and serves as a moving part. An octagonal connector 11 is provided at the top end of the integrated linear motor module 6; the octagonal connector 11 and the shouldered pin 12 cooperate to form a rotating pair, and are connected to the moving platform 2 through the rotating pair connecting assembly 10.

[0051] like Figure 5 To illustrate in detail, the four hinge points on the moving platform 2 are arranged in a trapezoidal shape. The hinge points of the two SPR branches 3 are located at the longer lower base of the trapezoid, while the hinge points of the two SPU branches 4 are located at the shorter upper base of the trapezoid.

[0052] The two SPU branches 4 are coupled together to a U-shaped auxiliary connecting frame 13 at their ends with Hooke's hinges 7. The U-shaped auxiliary connecting frame 13 has threaded holes at both ends, and a mating hole is also reserved at the corresponding installation position of the moving platform 2. The U-shaped auxiliary connecting frame 13 is fixedly connected to the moving platform 2 by passing a bolt through the mating hole and screwing it into the threaded hole.

[0053] Meanwhile, the SPR branch 3 is connected to the moving platform 2 through the rotating joint connection assembly 10, and the central axis of the rotating joint connection assembly 10 forms a 30-degree angle with the central axis of the moving platform 2. The two ends of the rotating joint connection assembly 10 are fixed to the moving platform 2 by threaded connection.

[0054] The four-branch parallel mechanism adopts a 2SPR-2SPU topology. Among them, the SPR branch 3 acts as a constraint branch, restricting the translation of the moving platform 2 along the X and Y axes, thereby constraining the mechanism to four degrees of freedom.

[0055] All four branches are driven by an integrated linear motor module 6, and the linear extension and retraction motion of each branch is coupled to the spatial motion of the moving platform 2.

[0056] Specifically: when the four branches are controlled to extend or contract synchronously and equally, the driving platform 2 can realize vertical translational motion along the Z-axis; by differentially driving the two SPR branches 3 and the two SPU branches 4 in terms of stroke, the driving platform 2 can be driven to rotate around the X-axis, Y-axis and Z-axis, thereby flexibly reproducing various postures of the biological neck. Example

[0057] like Figure 1 , Figure 7 As shown, the two SPR branches 3 and the two SPU branches 4 are stretched by the same amount, with each branch stretching 50 mm. After being driven by the integrated linear motor module 6, Figure 7 Compared to the dynamic platform 2 in the middle Figure 1 The moving platform 2 in the middle realizes translation along the Z-axis.

[0058] like Figure 1 , Figure 8 As shown, the two SPR branches 3 and the two SPU branches 4 are differentially driven. The extension and retraction of the two SPR branches 3 and the two SPU branches 4 are different. After being driven by the integrated linear motor module 6, Figure 8 Compared to the dynamic platform 2 in the middle Figure 1 The moving platform 2 in the middle realizes translation along the Z-axis, rotation around the X-axis, rotation around the Y-axis, and rotation around the Z-axis.

[0059] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A biomimetic robot neck joint mechanism based on a four-branch parallel structure, comprising a static platform (1) and a dynamic platform (2), characterized in that: Between the static platform (1) and the moving platform (2), there is an SPR branch group consisting of two SPR branches (3) and a branch group consisting of two SPU branches (4). The SPR branches (3) are constraint branches. Under the action of the two SPR branches (3) and the two SPU branches (4), the moving platform (2) outputs a four-degree-of-freedom spatial motion relative to the static platform (1), which includes three rotational degrees of freedom and one translational degree of freedom. The two SPR branches (3) are V-shaped and the two SPU branches (4) are inverted V-shaped. Both the SPR branches (3) and the SPU branches (4) include a combined ball joint assembly (5).

2. The biomimetic robot neck joint mechanism based on a four-branch parallel structure according to claim 1, characterized in that: The static platform (1) forms four mounting through holes (14), which are arranged in a trapezoidal shape. The two mounting through holes (14) that are closer in the upper base of the trapezoid are the near mounting hole group, and the mounting through holes (14) that are farther in the lower base of the trapezoid are the far mounting hole group. The S end of the SPR branch (3) is fixed in the near mounting hole group, and the S end of the SPU branch (4) is fixed in the far mounting hole group.

3. The biomimetic robot neck joint mechanism based on a four-branch parallel structure according to claim 1, characterized in that: The moving platform (2) forms four hinge positions, which are arranged in a trapezoidal shape. The two closer hinge positions in the upper base of the trapezoid are called near hinge positions, and the two farther hinge positions in the lower base of the trapezoid are called far hinge positions. The R end of the SPR branch (3) is fixed in the far hinge position, and the U end of the SPU branch (4) is fixed in the near hinge position.

4. The biomimetic robot neck joint mechanism based on a four-branch parallel structure according to claim 1, characterized in that: The spherical rotation output end of the combined ball joint component (5) in the SPU branch (4) is connected to the motor support frame (9). The motor support frame (9) is equipped with an integrated linear motor module (6) as a linear joint. The push rod (15) of the integrated linear motor module (6) is connected to the Hooke hinge (7).

5. The biomimetic robot neck joint mechanism based on a four-branch parallel structure according to claim 1, characterized in that: The spherical rotation output end of the combined ball joint component (5) in the SPR branch (3) is connected to the push rod (15) of the integrated linear motor module (6), and the body of the integrated linear motor module (6) and the moving platform (2) form a rotating pair.

6. The biomimetic robot neck joint mechanism based on a four-branch parallel structure according to claim 4, characterized in that: The combined ball joint assembly (5) includes a Hooke hinge (7) and a deep groove ball bearing (17). The outer ring of the deep groove ball bearing (17) is fitted with the end face of the stationary platform (1), and the inner ring is fixed to the shaft by an elastic retaining ring (8). A through hole is formed on the other side of the shaft. The through hole is aligned with the positioning hole of the Hooke hinge (7) to achieve the connection between the two.

7. A biomimetic robot neck joint mechanism based on a four-branch parallel structure according to claim 5, characterized in that: The rotating pair includes an octagonal connector (11) at the end of the integrated linear motor module (6) body. The octagonal connector (11) forms a rotating pair with the rotating pair connection assembly (10) through a shoulder pin (12).

8. A biomimetic robot neck joint mechanism based on a four-branch parallel structure according to claim 7, characterized in that: The rotating pair connection assembly (10) is fixed to the moving platform (2) by means of a threaded connection.

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