A three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle actuation

Abstract

This invention belongs to the field of biomimetic robot technology, specifically disclosing a three-degree-of-freedom parallel biomimetic eye actuator based on flexible artificial muscle actuation. It includes a hemispherical biomimetic eye structure, on which a three-degree-of-freedom flexible body actuation structure is mounted. At the end of the three-degree-of-freedom flexible body actuation structure furthest from the hemispherical biomimetic eye structure, there is a base platform connected to the hemispherical biomimetic eye structure via a ball joint. A trolley structure that cooperates with the three-degree-of-freedom flexible body actuation structure is mounted on the base platform. This invention uses a universal ball joint to connect the hemispherical biomimetic eye structure to the base platform, and coordinates with the flexible eye muscle of the three-degree-of-freedom flexible body actuation structure for actuation. By adjusting six artificial muscles (rectus and oblique muscles), the biomimetic eye using this actuator can achieve yaw, pitch, and roll motion postures, meeting the requirements of a compact structure, high precision, low noise, and high motion flexibility.

Description

Technical Field

[0001] This invention belongs to the field of bionic robot technology, specifically relating to a three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle drive. Background Technology

[0002] With the continuous breakthroughs in visual bionics in cutting-edge fields such as robotics, bionic eye technology, which focuses on both visual perception and eye movement control, has become an important part of the field of bionic robots. Since the visual system of primates has flexible control and visual perception capabilities, existing bionic eye technology can simulate the structure and visual function of the eyeball of primates, giving it characteristics or functions similar to the eyes of biological systems.

[0003] Existing research on bionic eye technology mainly focuses on realizing the ability of eye movement, rather than realizing the bionic function of primate eyes. However, bionic eyes with bionic functions are closer to primate eyes and can effectively ensure the flexibility and stable visual perception of the bionic eye system.

[0004] The movement of primate eyes is mainly controlled by six extraocular muscles attached to the eyeball. However, existing bionic eyes mostly use springs, rods, etc. to simulate the movement of extraocular muscles. In actual simulation adjustment, springs and rods not only produce abnormal noise, but this noise cannot be avoided by existing means. Furthermore, due to the limitations of springs and rods in simulating extraocular muscles, the simulated extraocular muscles cannot be precisely adjusted. As a result, existing bionic eyes are noisy, have low movement flexibility, and are difficult to achieve high-precision adjustment.

[0005] Chinese Patent CN110497389B discloses a rope-spring driven three-degree-of-freedom parallel bionic eye actuator, which mainly comprises a three-degree-of-freedom parallel mechanism and three rope drive branches. Each of the three branches of the three-degree-of-freedom parallel mechanism has three springs, ensuring that the moving platform is always subjected to forces in opposite directions of the rope tension. The three drive rods drive the moving platform through the ropes, achieving three-degree-of-freedom motion. A camera mounted on the moving platform can also achieve three-degree-of-freedom motion. This mechanism has the advantages of fewer drives, a compact structure, high speed, high rigidity, and high precision. However, this rope-spring driven three-degree-of-freedom parallel bionic eye actuator, while using ropes and springs, suffers from drawbacks such as high noise and low motion flexibility. Furthermore, it is difficult to achieve high-precision adjustment of the bionic eye through spring drive alone. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a three-degree-of-freedom parallel bionic eye actuator based on artificial muscle flexible actuation, which is compact, highly precise, low-noise, and highly flexible in motion.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] A three-degree-of-freedom parallel bionic eye actuator based on artificial muscle flexible drive includes a hemispherical bionic eye structure, a three-degree-of-freedom flexible body drive structure on the hemispherical bionic eye structure, a base platform connected to the hemispherical bionic eye structure by a ball joint at the end of the three-degree-of-freedom flexible body drive structure away from the hemispherical bionic eye structure, and a trolley structure that cooperates with the three-degree-of-freedom flexible body drive structure on the base platform.

[0009] Furthermore, the hemispherical bionic eye structure includes a bionic eye hemispherical shell, an inner boss on the inner top surface of the bionic eye hemispherical shell, and an image acquisition device mounted on the bionic eye hemispherical shell; a moving platform support is provided inside the bionic eye hemispherical shell.

[0010] Furthermore, the three-degree-of-freedom flexible body driving structure includes an eye muscle flexible body disposed on the bionic eye hemisphere shell and fitted onto the surface of the bionic eye hemisphere shell. The eye muscle flexible body includes a bionic eye hemisphere surface fitted onto the bionic eye hemisphere shell and in contact with the bionic eye hemisphere shell. A camera hole for cooperating with an image acquisition device is provided at the center of the bionic eye hemisphere surface. Rectangular muscle flexible bodies with gap fit are symmetrically disposed on the bionic eye hemisphere surface, and oblique muscle flexible bodies with gap fit are symmetrically disposed on the bionic eye hemisphere surface. The oblique muscle flexible bodies are connected to the bionic eye hemisphere surface through oblique muscle connectors disposed on the bionic eye hemisphere surface.

[0011] Furthermore, the rectus muscle flexible bodies are distributed in four positions on the upper, lower, left, and right sides of the bionic eye hemisphere. The rectus muscle flexible bodies are directly connected to the muscle actuators, and there are four rectus muscle flexible bodies in total. There are two oblique muscle flexible bodies, and the connection between the two oblique muscle flexible bodies is located on the same side of the bionic eye hemisphere. The oblique muscle flexible bodies pass through the trolley structure on the other side and are connected to the muscle actuators. The bionic eye hemisphere, rectus muscle flexible bodies, and oblique muscle flexible bodies in the eye muscle flexible body are all made of silicone casting molds, and the ratio of silicone to curing agent is 50:1.

[0012] Furthermore, the trolley structure includes a limiting frame that cooperates with the oblique muscle flexible body, and rollers are provided at both ends of the limiting frame. The rollers are connected to the limiting frame through fixed terminals.

[0013] Furthermore, the limiting frame includes a limiting support rod, and both ends of the limiting support rod are provided with a C-shaped limiting rod that cooperates with the roller and the fixed terminal. The C-shaped limiting rod is sleeved on the oblique muscle flexible body and is in clearance fit with the oblique muscle flexible body.

[0014] Furthermore, the end of the limiting rod is provided with a hollow roller that mates with the C-shaped limiting rod. The hollow roller is sleeved inside the roller and has a clearance fit with the roller. The hollow roller is connected to a connecting shaft set on the fixed terminal, and the connecting shaft mates with the hollow part of the hollow roller. The end of the fixed terminal away from the hollow roller has a clearance fit with the C-shaped limiting rod. The trolley structure is installed on one side of the base platform. A limiting ring is sleeved on the C-shaped limiting rod, and the limiting ring mates with a limiting ring groove set on the C-shaped limiting rod. Each side of the limiting ring is provided with a side ring groove, and an annular adjusting plate is provided in the side ring groove. The annular adjusting plate is connected to the annular adjusting plate on the side of the adjacent limiting ring through an adjusting bearing.

[0015] Furthermore, the optical axis of the image acquisition device passes through the center of the bionic eyeball, and the direction of the optical axis of the image acquisition device coincides with the line of sight of the bionic eye; the moving platform support is provided with an arc-shaped slot to accommodate the power cord and data cable.

[0016] Furthermore, the moving platform support is equipped with a universal ball joint that connects to the base platform. The ball joint of the universal ball joint is connected to the center of the moving platform support. The bottom of the universal ball joint is connected to the base platform by bolts, and the ball joint is connected to the moving platform support of the hemispherical bionic eye, forming a spherical rotating pair.

[0017] Furthermore, the diameter of the base platform is smaller than the inner diameter of the bionic eye hemisphere shell, so that it does not interfere with the bionic eye hemisphere shell and the flexible eye muscle when the bionic eyeball rotates. The base platform has an arc-shaped groove to accommodate power cables and data cables.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) This invention uses a universal ball joint to connect a hemispherical bionic eye structure on a base platform, and drives it with a flexible eye muscle of a three-degree-of-freedom flexible body drive structure. By adjusting the six artificial muscles of the rectus muscle flexible body and the oblique muscle flexible body, the bionic eye using this bionic eye actuator has three motion postures: yaw, pitch and roll. This bionic eye actuator can achieve adjustment of three rotational degrees of freedom, which is more in line with the movement form of primate eyes and closer to the bionic function of primate eyes. It can meet the requirements of compact structure, high precision, low noise and high movement flexibility of bionic eyes.

[0020] (2) The present invention uses a silicone casting mold to make the flexible eye muscle in the artificial muscle. The flexible eye muscle has a total of six flexible bodies, including four rectus muscles and two oblique muscles, which are biomimetic to the six extraocular muscles of primates: superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique and inferior oblique muscles. The biomimetic eye using the actuator of this biomimetic eye conforms to the eyeball structure of primates and can realize the low noise, high precision and high flexibility adjustment of the biomimetic eye.

[0021] (3) The present invention uses a trolley structure in conjunction with two upper and lower oblique muscle flexible bodies to adjust the bionic eye hemisphere shell through the bionic eye hemisphere, which facilitates the rolling motion of the bionic eye. This makes the bionic eye using the present invention more in line with the rolling motion mechanism of primate eyes. In addition, with the upper, lower, left and right four rectus muscle flexible bodies to adjust the bionic eye hemisphere shell through the bionic eye hemisphere, the yaw and pitch motion of the bionic eye can be realized. The present invention can perfectly realize the three motion postures of the bionic eye: yaw, pitch and roll, and has three degrees of freedom adjustment capability, which can realize the purpose of three degrees of freedom adjustment of the bionic eye.

[0022] (4) In this invention, the flexible eye muscle body is combined with the universal ball joint, and the four flexible rectus muscles cooperate up and down and left and right to realize two rotational degrees of freedom for the yaw and pitch movements of the bionic eye; the flexible eye muscle body is combined with the universal ball joint and the trolley structure, and the two flexible oblique muscles cooperate to realize one rotational degree of freedom for the roll movement of the bionic eye; a total of three degrees of freedom; the flexible rectus muscles, the flexible oblique muscles and the hemisphere of the bionic eye in this invention are all made of artificial muscle flexible bodies, and the parallel drive of the artificial muscle flexible bodies makes the actuator of this bionic eye have the characteristics of compact structure, high precision and low noise.

[0023] (5) The present invention includes a hemispherical bionic eye structure, a trolley structure and a three-degree-of-freedom flexible body drive structure. The hemispherical bionic eye structure is mainly composed of a bionic eye hemispherical shell and a moving platform support, which is connected to the base platform through a universal ball joint. The bionic eye hemispherical shell is driven by the eye muscle flexible body of the three-degree-of-freedom flexible body drive structure. The trolley structure is composed of a limiting frame, a roller and a fixed terminal. By stretching the four straight muscle flexible bodies of the eye muscle flexible body, the bionic eye has two degrees of freedom. By pulling the two oblique muscle flexible bodies through the trolley structure, the bionic eye can rotate around the line of sight axis, thereby giving it a third degree of freedom. The present invention uses artificial muscle flexible bodies and trolley structure to control the bionic eye, so that the movement of the bionic eye conforms to the movement mechanism of the human eye, and has the characteristics of compact structure, high precision and low noise.

[0024] (6) The four rectus muscle flexible bodies of the present invention are attached to the front part of the equator of the bionic eye hemisphere. The superior oblique muscle flexible body passes through the pulley and is attached to the upper part of the rear half of the equator of the bionic eye hemisphere. The inferior oblique muscle flexible body, corresponding to the superior oblique muscle flexible body, passes through the pulley and is attached to the lower part of the rear half of the equator of the bionic eye hemisphere. The contraction of the superior and inferior rectus muscle flexible bodies can control the bionic eye hemisphere to move vertically around the pitch axis. The contraction of the left and right rectus muscle flexible bodies will form the horizontal movement of the bionic eye hemisphere around the yaw axis. When the superior oblique muscle flexible body contracts, it will cause the bionic eye hemisphere to twist inward around the roll axis. When the inferior oblique muscle flexible body contracts, it will cause the bionic eye hemisphere to twist outward around the roll axis. It has three degrees of freedom. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention in Embodiment 1;

[0026] Figure 2 This is a front view of the present invention in Embodiment 1;

[0027] Figure 3 This is a schematic diagram of the structure of the present invention in Embodiment 1;

[0028] Figure 4 This is a schematic diagram of the hemispherical bionic eye structure of the present invention in Example 1;

[0029] Figure 5 This is a schematic diagram of the trolley structure of the present invention in Embodiment 1;

[0030] Figure 6 This is an exploded view of the present invention in Embodiment 1;

[0031] Figure 7 This is a schematic diagram of the motion direction of the three motion postures of yaw, pitch and roll in Embodiment 1 of the present invention.

[0032] In the figure, the components are: image acquisition device 1, flexible eye muscle body 2, bionic eye hemispherical shell 3, moving platform support 4, limiting frame 5, roller 6, fixed terminal 7, base platform 8, universal ball joint 9, bionic eye hemispherical surface 10, oblique muscle flexible body 11, rectus muscle flexible body 12, rectus muscle flexible body 13, rectus muscle flexible body 14, oblique muscle flexible body 15, rectus muscle flexible body 16, limiting support rod 17, U-shaped limiting rod 18, hollow roller 19, connecting shaft 20, and inner boss 21. Detailed Implementation

[0033] The present invention will be further described in detail below through specific embodiments, but this does not limit the scope of the present invention.

[0034] Example 1

[0035] A three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle actuation, its structure is as follows: Figure 1-7 As shown, it includes a hemispherical bionic eye structure, on which a three-degree-of-freedom flexible body drive structure is provided. At the end of the three-degree-of-freedom flexible body drive structure away from the hemispherical bionic eye structure, there is a base platform 8 that is connected to the hemispherical bionic eye structure by a ball joint. The base platform 8 is provided with a trolley structure that cooperates with the three-degree-of-freedom flexible body drive structure.

[0036] The hemispherical bionic eye structure includes a bionic eye hemispherical shell 3. An inner boss 21 is provided on the inner top surface of the bionic eye hemispherical shell 3, and the inner boss 21 is connected to an image acquisition device 1 mounted on the bionic eye hemispherical shell 3. A moving platform support 4 is provided inside the bionic eye hemispherical shell 3. The optical axis of the image acquisition device 1 passes through the center of the bionic eye, and its direction coincides with the line of sight of the bionic eye.

[0037] The three-degree-of-freedom flexible body driving structure includes an eye muscle flexible body 2 disposed on and fitted to the surface of the bionic eye hemisphere shell 3. The eye muscle flexible body 2 includes a bionic eye hemisphere 10 fitted on and in contact with the bionic eye hemisphere shell 3. Symmetrically arranged on the bionic eye hemisphere 10 are rectilinear flexible bodies 12, 14, 13, and 16 with gap fit, and symmetrically arranged on the bionic eye hemisphere 10 are oblique flexible bodies 11 and 15 with gap fit to the rectilinear flexible bodies 12, 14, 13, and 16. The rectilinear flexible bodies 12, 14, 13, and 16 are distributed at four positions on the upper, lower, left, and right sides of the bionic eye hemisphere 10, with a total of four rectilinear flexible bodies 12, 14, 13, and 16; the oblique flexible bodies 11 and 15 are two in number, with the connection point of the two oblique flexible bodies 11 and 15 located on the same side of the bionic eye hemisphere 10.

[0038] The trolley structure includes a limiting frame 5 that mates with the oblique muscle flexible bodies 11 and 15. Rollers 6 are provided at both ends of the limiting frame 5, and the rollers 6 are connected to the limiting frame 5 via fixed terminals 7. The limiting frame 5 includes a limiting support rod 17, and both ends of the limiting support rod 17 are provided with U-shaped limiting rods 18 that mate with the rollers 6 and fixed terminals 7. The U-shaped limiting rods 18 are sleeved on the oblique muscle flexible bodies 11 and 15 and are in clearance fit with them. A hollow roller 19 is provided at the end of the limiting support rod 17 that mates with the U-shaped limiting rod 18. The hollow roller 19 is sleeved inside the rollers 6 and is in clearance fit with them. The hollow roller 19 is connected to a connecting shaft 20 provided on the fixed terminal 7.

[0039] The moving platform support 4 is equipped with a universal ball joint 9 that connects to the base platform 8. The ball joint 9 is connected to the moving platform support 4. The diameter of the base platform 8 is smaller than the inner diameter of the bionic eye hemispherical shell 3, and the base platform 8 has an arc-shaped groove.

[0040] Based on the adjustment requirements of the bionic eye, a three-degree-of-freedom flexible body drive structure, in conjunction with a trolley structure, drives the hemispherical bionic eye structure to perform three-degree-of-freedom adjustment movements. By stretching the four rectus flexible bodies 12, 14, 13, and 16 of the eye muscle flexible body 2, the bionic eye gains two degrees of freedom. The trolley structure pulls the two oblique flexible bodies 11 and 15, allowing the bionic eye to rotate around its visual axis, thus granting it a third degree of freedom. During the adjustment of the rectus flexible bodies 12, 14, 13, and 16 and the oblique flexible bodies 11 and 15, the hemispherical surface 10 of the bionic eye adjusts accordingly. The hemispherical surface 10 of the bionic eye drives the image acquisition unit 1 and its internal components. The boss 21 and the bionic eye hemisphere shell 3 rotate along the universal ball joint 9 on the base platform 8 via the moving platform support 4, thereby realizing the three-degree-of-freedom bionic adjustment action of the image acquisition device 1. Specifically, the contraction of the superior rectus muscle flexible body 12 and the inferior rectus muscle flexible body 14 can control the bionic eye hemisphere 10 to move vertically around the pitch axis as the rotation axis. The contraction of the left rectus muscle flexible body 13 and the right rectus muscle flexible body 16 will cause the bionic eye hemisphere 10 to move horizontally around the yaw axis. When the superior oblique muscle flexible body 11 contracts, it will cause the bionic eye hemisphere 10 to twist inward around the roll axis as the rotation axis. When the inferior oblique muscle flexible body 15 contracts, it will cause the bionic eye hemisphere 10 to twist outward around the roll axis, thus having a total of three degrees of freedom.

[0041] When the two oblique muscle flexible bodies 11 and 15 pass through the trolley structure, they move within the U-shaped limiting rod 18 of the limiting frame 5. The limiting rod 17 restricts the distance between the two oblique muscle flexible bodies 11 and 15 to a certain range, preventing deviation interference during adjustment and preventing malfunctions caused by interference during the adjustment of the bionic eye. During adjustment, the roller 6 rotates along the hollow roller 19, converting the adjustment of the oblique muscle flexible bodies 11 and 15. To facilitate rolling adjustment, reduce frictional loss of the oblique muscle flexible bodies 11 and 15, and extend their service life; the fixed terminal 7 is connected to the hollow roller 19 via the connecting shaft 20 to prevent the oblique muscle flexible bodies 11 and 15 from detaching from the U-shaped limiting rod 18, allowing the oblique muscle flexible bodies 11 and 15 to be adjusted stably for a long time. At the same time, the detachable connection between the connecting shaft 20 and the hollow roller 19 facilitates the installation, replacement, and maintenance of the oblique muscle flexible bodies 11 and 15, enabling quick maintenance during usage intervals.

[0042] Example 2

[0043] A three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle drive differs from Embodiment 1 in that: the platform support is made of a circular plate, and the connection between the platform support and the bionic eye hemispherical shell 3 is coated with sealant to adapt to different environmental requirements.

[0044] Example 3

[0045] A three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle drive differs from Embodiment 1 in that: a limiting ring is sleeved on the C-shaped limiting rod 18, the limiting ring cooperates with the limiting ring groove provided on the C-shaped limiting rod 18, and a side ring groove is provided on the side of the limiting ring, and an annular adjusting plate is provided in the side ring groove. The annular adjusting plate is connected to the annular adjusting plate on the side of the adjacent limiting ring through the adjusting bearing.

[0046] The above description is only a preferred embodiment of the present invention, but is not limited to the above examples. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle actuation, characterized in that, It includes a hemispherical bionic eye structure, on which a three-degree-of-freedom flexible body drive structure is set. At the end of the three-degree-of-freedom flexible body drive structure away from the hemispherical bionic eye structure, there is a base platform that is connected to the hemispherical bionic eye structure by a ball joint. On the base platform, there is a trolley structure that cooperates with the three-degree-of-freedom flexible body drive structure. The hemispherical bionic eye structure includes a bionic eye hemispherical shell, an inner boss on the inner top surface of the bionic eye hemispherical shell, and an image acquisition device mounted on the bionic eye hemispherical shell; a moving platform support is provided inside the bionic eye hemispherical shell. The three-degree-of-freedom flexible body driving structure includes an eye muscle flexible body disposed on the bionic eye hemisphere shell and fitted onto the surface of the bionic eye hemisphere shell. The eye muscle flexible body includes a bionic eye hemisphere surface fitted onto the bionic eye hemisphere shell and attached to the bionic eye hemisphere shell. Rectangular muscle flexible bodies with gap fit and oblique muscle flexible bodies with gap fit are symmetrically arranged on the bionic eye hemisphere surface. The trolley structure includes a limiting frame that cooperates with the oblique muscle flexible body. Rollers are provided at both ends of the limiting frame, and the rollers are connected to the limiting frame through fixed terminals. The limiting frame includes a limiting support rod, and both ends of the limiting support rod are provided with a C-shaped limiting rod that cooperates with the roller and the fixed terminal. The C-shaped limiting rod is sleeved on the oblique muscle flexible body and is in clearance fit with the oblique muscle flexible body. The end of the limiting support rod is provided with a hollow roller that cooperates with the U-shaped limiting rod. The hollow roller is sleeved inside the drum and has a clearance fit with the drum. The hollow roller is connected to the connecting shaft provided on the fixed terminal.

2. The three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle drive according to claim 1, characterized in that, The rectus muscles are distributed in four positions on the upper, lower, left, and right sides of the bionic eye hemisphere, and there are four rectus muscles. There are two oblique muscles, and the connection between the two oblique muscles is located on the same side of the bionic eye hemisphere.

3. The three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle drive according to claim 1, characterized in that, The optical axis of the image acquisition device passes through the center of the bionic eyeball, and its direction coincides with the line of sight of the bionic eye.

4. The three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle drive according to claim 1, characterized in that, The moving platform support is equipped with a universal ball joint that is connected to the base platform, and the ball joint of the universal ball joint is connected to the moving platform support.

5. The three-degree-of-freedom parallel bionic eye actuator based on flexible artificial muscle drive according to claim 1, characterized in that, The diameter of the base platform is smaller than the inner diameter of the bionic eye hemisphere shell, and an arc groove is opened on the base platform.

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