A universal ball structure for multi-degree-of-freedom unit replication

Abstract

The present invention discloses a universal ball structure for multi-degree-of-freedom unit replication, which is composed of any number of universal ball units connected in series. Each universal ball unit includes two motion platforms and at least three sets of rotating member groups arranged in parallel between the two motion platforms; each rotating member group includes an upper rotating member, a middle rotating member, and a lower rotating member. Each universal ball unit of the present invention can achieve two-degree-of-freedom deflection motion, and all universal ball units have a linkage feature, generating exactly the same deflection, so as to achieve bending motion through a series of universal ball units. The present invention can achieve bending operations in narrow spaces, and has the characteristics of small footprint, large turning angle, high load, light weight, rear drive, and internal wire routing, so as to meet the miniaturization, simplification, and high-performance operation requirements of minimally invasive surgical instruments or robots operating in narrow spaces.

Description

Technical Field

[0001] The present invention belongs to the mechanical transmission structure, and particularly relates to a universal ball structure for multi-degree-of-freedom unit replication. Background Art

[0002] For fine and dexterous operations in narrow spaces, the robotic arm needs to reduce its size, streamline its volume, and reduce its mass. At the same time, it should have more degrees of freedom, higher load capacity, and larger movement range. These requirements are mutually contradictory and often lead to one-sided considerations.

[0003] The current solutions mainly include rigid joint arms and flexible continua. For rigid joint arms, a micro motor can be built into the joint, sacrificing the advantage of rear drive. However, the micro motor cannot provide a large load capacity. Or a cable drive combined with pulleys at the joints can be used, where a rear motor pulls a steel wire rope to drive the pulley to drive the rotation of the joint. However, the rotation range is limited, and a large pre-tightening force is required to prevent the pulley from slipping. These solutions all have extremely high difficulties in internal wiring, requiring a large amount of space for the movement of transmission cables, and also considering communication lines and power supply lines. Flexible continua use elastic pipes, which are naturally suitable for hollow wiring, and the deformation of the elastic body can achieve flexible bending motion forms. However, its deformation is easily affected by external environmental forces, making it difficult to achieve precise positioning and having a low load capacity. Summary of the Invention

[0004] In order to meet the requirements of robotic arm operations in narrow spaces, while taking into account the excellent characteristics of small footprint, large rotation angle, high load, lightweight, rear drive, and internal wiring, the present invention realizes the unique curvature bending motion form of the flexible continuum based on the spherical link structure, and provides a universal ball structure with multi-degree-of-freedom bending ability.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention first provides a universal ball structure for multi-degree-of-freedom unit replication, which is composed of any number of universal ball units connected in series.

[0007] Each universal ball unit includes two moving platforms and at least three groups of rotating member groups arranged in parallel between the two moving platforms; the two moving platforms are the first moving platform and the second moving platform respectively, and both the first moving platform and the second moving platform have a rotation center.

[0008] Each rotating member group includes an upper rotating member, a middle rotating member, and a lower rotating member; one end of the upper rotating member is hinged to the first motion platform, and the axes of the hinge shafts of the two pass through the rotation center of the first motion platform; one end of the lower rotating member is hinged to the second motion platform, and the axes of the hinge shafts of the two pass through the rotation center of the second motion platform; one end of the middle rotating member is hinged to the other end of the upper rotating member, and the axes of the hinge shafts of the two pass through the rotation center of the first motion platform, and the other end of the middle rotating member is hinged to the other end of the lower rotating member, and the axes of the hinge shafts of the two pass through the rotation center of the second motion platform;

[0009] Two adjacent universal ball units are connected in series through the connection between the motion platforms; the groups of rotating parts of the adjacent universal ball units correspond one to one, and the corresponding groups of rotating parts are transmission-connected.

[0010] It should be noted that the structures of the first motion platform and the second motion platform of the present invention can be the same or different, and the structures of the upper rotating member and the lower rotating member can be the same or different. Therefore, the upper and lower ends of each universal ball unit can be reversed, and after being reversed, they can still be connected in series to the universal ball structure.

[0011] As a preferred solution of the present invention, the middle rotating member includes a first rotating part and a second rotating part hinged to each other, wherein the middle rotating member is hinged to the upper rotating member through the first rotating part; the middle rotating member is hinged to the lower rotating member through the second rotating part.

[0012] As a preferred solution of the present invention, in the universal ball unit, each upper rotating member and the axis of the hinge shaft of the first motion platform are located in the same plane, and the angles between two adjacent hinge shaft axes in the plane are equal.

[0013] As a preferred solution of the present invention, in the universal ball unit, the axes of the hinge shafts of each lower rotating member and the second motion platform are located in the same plane, and the angles between the axes of two adjacent hinge shafts in the plane are equal.

[0014] As a preferred embodiment of the present invention, there are three groups of rotating parts in each universal ball unit, and the structures of the three groups of rotating parts are exactly the same; the upper rotating part and the lower rotating part have the same structure, and the first motion platform and the second motion platform have the same structure. At this time, the movement of the first motion platform and the second motion platform has a mirror image characteristic.

[0015] As a preferred embodiment of the present invention, the upper rotating member and the lower rotating member on the rotating member group of each universal ball unit are processed into external gears, the rotation axis of the external gear of the upper rotating member is the hinge axis between it and the first moving platform, and the rotation axis of the external gear of the lower rotating member is the hinge axis between it and the second moving platform; the upper rotating member on the rotating member group of each universal ball unit and the lower rotating member of the universal ball unit located above it are transmitted through gear meshing.

[0016] As a preferred embodiment of the present invention, there is always a mirror symmetry relationship between the upper rotating member and the lower rotating member driven by gear meshing, that is, the included angle between the upper rotating member and the first moving platform within its unit is always equal to the included angle between the lower rotating member and the second moving platform within its unit.

[0017] As an alternative embodiment of the present invention, the upper rotating member of the universal ball unit and the lower rotating member of the adjacent universal ball unit are of an integral structure, and the bases and moving platforms of the adjacent universal ball units in contact and connection are also of an integral structure. In this embodiment, the adjacent universal ball units do not have consistent motion, but the motion can be transmitted in pairs, that is, each universal ball unit has the same motion as the universal ball unit two before it, and the adjacent moving units have a linkage characteristic in motion.

[0018] For other alternative embodiments, when the motions of the first moving platform and the second moving platform of the universal ball unit do not have a mirror characteristic, the next universal ball unit can be arranged in a mirror image, that is, the next universal ball unit is inverted, its first moving platform is installed on the first moving platform of the current universal ball unit, and its second moving platform is connected to the second moving platform of the universal ball unit two after it. Moreover, the upper rotating member and the lower rotating member on the rotating member group of each universal ball unit both adopt the preferred gear meshing design, and there is always a mirror symmetry relationship between the upper rotating members of adjacent universal ball units, that is, the included angles between the upper rotating members of the two side units and the first moving platforms within their units are equal, and the included angles between the lower rotating members of the two side units and the second moving platforms within their units are equal. Through the mirror-image arranged universal ball units and the gear meshing pairs of the upper rotating members and the gear meshing pairs of the lower rotating members installed in a mirror symmetry relationship, the motion can be transmitted in pairs, that is, each universal ball unit has the same motion as the universal ball unit two before it, and the adjacent moving units have a linkage characteristic in motion.

[0019] The beneficial effects of the present invention are that each universal ball unit of the present invention can achieve at least two-degree-of-freedom deflection, and all universal ball units have a linkage characteristic and will produce exactly the same deflection, so as to realize a bending motion through a series of universal ball units. By combining the preferably mirror-characteristic universal ball units, or by combining non-mirror-characteristic universal ball units in pairs, a replicated universal ball unit with single-motion replication and a replicated universal ball pair with paired-motion replication can be obtained respectively. By combining different numbers of two-degree-of-freedom or three-degree-of-freedom replicated universal ball units or replicated universal ball pairs, robotic arms of different lengths can be formed, and through bending motion and telescopic motion, flexible operation in a restricted space can be realized.

[0020] The present invention can realize bending operation in a narrow space, and has the characteristics of small footprint, large rotation angle, high load, light weight, rear drive, and internal wire routing, so as to meet the miniaturization, simplification, and high-performance operation requirements of minimally invasive surgical instruments or robots for operation in a narrow space. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of a universal ball unit shown in the embodiment;

[0022] Figure 2 It is a schematic structural diagram of a rotating member group shown in the embodiment;

[0023] Figure 3 For Figure 1 It is a schematic motion diagram of the universal ball unit shown;

[0024] Figure 4 It is a schematic structural diagram of another rotating member group shown in the embodiment;

[0025] Figure 5 It is an exploded view of another universal ball unit shown in the embodiment;

[0026] Figure 6 It is a schematic diagram of the transmission between universal ball units shown in the embodiment;

[0027] Figure 7 It is a schematic diagram of a universal ball structure for multi-degree-of-freedom unit replication shown in the embodiment;

[0028] Figure 8 It is a schematic diagram of another universal ball structure for multi-degree-of-freedom unit replication shown in the embodiment.

[0029] In the figure: the second moving platform 1, the first moving platform 2, the rotating member group 3, the upper rotating member 31, the lower rotating member 32, the middle rotating member 33, the first rotating part 331, the second rotating part 332. Detailed Embodiments

[0030] The present invention will be further described and explained below in conjunction with the detailed embodiments. The embodiments are only examples of the present disclosure and do not delimit the scope of limitation. The technical features of each embodiment of the present invention can be combined correspondingly without conflict.

[0031] The present invention provides a universal ball structure for multi-degree-of-freedom unit replication, which is composed of any number of universal ball units connected in series. As Figure 1 It shows a schematic structural diagram of a universal ball unit. The universal ball unit includes a second moving platform 1, a first moving platform 2, and at least three groups of rotating member groups 3 located between the two moving platforms; both the second moving platform and the first moving platform have a rotation center (the second moving platform and the first moving platform can swing around their respective rotation centers). In Figure 1In the symmetric structure shown, the rotation center is the center of the second moving platform and the first moving platform; it should be noted that the universal ball unit of the present invention can also be an asymmetric structure.

[0032] As Figure 1 and 2 shown, in a preferred embodiment of the present invention, each rotating member group 3 includes an upper rotating member 31, a middle rotating member 33, and a lower rotating member 32; one end of the upper rotating member 31 is hinged to the first moving platform 2, and the axis of the hinge shaft between the two passes through the rotation center of the first moving platform 2; one end of the lower rotating member 32 is hinged to the second moving platform 1, and the axis of the hinge shaft between the two passes through the rotation center of the second moving platform 1; one end of the middle rotating member 33 is hinged to the other end of the upper rotating member 31, and the axis of the hinge shaft between the two passes through the rotation center of the first moving platform 2, and the other end of the middle rotating member 33 is hinged to the other end of the lower rotating member 32, and the axis of the hinge shaft between the two passes through the rotation center of the second moving platform 1. Inside the universal ball unit, the axes of the hinge shafts of the upper rotating members and the first moving platform are located in the same plane, and the included angles between adjacent two hinge shaft axes in the plane are equal to 120°. The axes of the hinge shafts of the lower rotating members and the second moving platform are located in the same plane, and the included angles between adjacent two hinge shaft axes in the plane are equal to 120°.

[0033] In a specific embodiment of the present invention, the upper rotating member 31, the middle rotating member 33, and the lower rotating member 32 are all designed as mechanical components with a certain mechanical strength, and their shapes are not limited. For example, they can be rod-shaped, plate-shaped, or other shapes or a combined structure of multiple shapes. The second moving platform and the first moving platform are designed to facilitate the series connection between the units, and their specific shapes are not limited; preferably, one end of the upper rotating member is hinged and installed inside the first moving platform, and one end of the lower rotating member is hinged and installed inside the second moving platform.

[0034] Figure 3 For Figure 1 the motion simulation diagram of the universal ball unit shown, in order to clearly show Figure 1 the motion characteristics of the universal ball unit shown, Figure 3 the mechanical structures in Figure 3In the figure, A represents the first motion platform, and B represents the second motion platform; the hinge axes that connect the first motion platform to the three upper rotating parts are denoted as A1, A2 and A3 respectively, and the three hinge axes intersect at 1 point, which is the rotation center of the first motion platform; the second motion platform also has three hinge axes that connect the second motion platform to the three lower rotating parts, and the three hinge axes intersect at 1 point, which is the rotation center of the second motion platform; B1 is one of the three hinge axes. One hinge axis between the upper rotating part and the middle rotating part is denoted as C1, which points to the rotation center of the first motion platform; one hinge axis between the lower rotating part and the middle rotating part is denoted as D1, which points to the rotation center of the second motion platform. Refer to Figure 3 , the present invention Figure 1 The universal ball unit can swing in two directions, that is, the universal ball unit can be driven to generate two-degree-of-freedom motion.

[0035] In order to realize the serial connection of each universal ball unit, two adjacent universal ball units are connected in series through the connection between the motion platforms, and each group of rotating parts of the adjacent universal ball units corresponds to each other, and the corresponding rotating parts groups are connected by transmission; wherein the connection between the two motion platforms can be the first motion platform connected to the second motion platform, the first motion platform connected to the first motion platform, or the second motion platform connected to the second motion platform. Taking the first motion platform connected to the second motion platform as a typical embodiment, the second motion platform 1 of the universal ball unit is in contact with the first motion platform 2 of the adjacent universal ball unit located below it, and the first motion platform 2 of the universal ball unit is in contact with the second motion platform 1 of the adjacent universal ball unit located above it; the second motion platform 1 and the first motion platform 2 of the adjacent universal ball units that are in contact with each other are fixedly connected or are an integrated structure, and each group of rotating parts of the adjacent universal ball units corresponds to each other, and the upper rotating part 31 of each universal ball unit is in transmission connection with the lower rotating part 32 on the corresponding rotating part group of the universal ball unit located above it, so as to realize the transmission of motion.

[0036] Figure 1 Although the universal ball unit shown can realize the rotation of the first motion platform, since the lengths of the three middle rotating members 33 are fixed, the entire universal ball unit cannot realize the telescopic movement between the rotation center of the first motion platform and the rotation center of the second motion platform. Figure 4 and 5 As shown, in an optional embodiment of the present invention, the middle rotating member 33 is designed to include a first rotating part 331 and a second rotating part 332 that are hinged to each other, wherein the middle rotating member is hinged to the upper rotating member 31 through the first rotating part 331, and the axes of the hinge shafts of the two pass through the rotation center of the first motion platform 2; the middle rotating member is hinged to the lower rotating member 32 through the second rotating part 332, and the axes of the hinge shafts of the two pass through the rotation center of the second motion platform 1. Figure 4In this case, since the hinge angle between the first rotating part 331 and the second rotating part 332 can be changed, when the hinge angle is changed, the length of the entire middle rotating part 33 can be changed, so that the distance between the second moving platform 1 and the first moving platform 2 can be changed, so that the universal ball unit can not only swing in two degrees of freedom, but also realize the telescopic movement between the platform rotation center and the second moving platform rotation center. In Figure 4 and Figure 5 's structural design, the universal ball unit can be driven to generate three-degree-of-freedom motion.

[0037] In order to realize the transmission of motion between the universal ball units, the upper rotating parts of the universal ball units need to be in transmission connection with the lower rotating parts on the corresponding rotating part groups of the universal ball units located above them. A relatively ideal transmission method is gear transmission. As Figure 1 、 2 、4 and 5 show, the universal ball units are all designed to use gear transmission.

[0038] In a preferred embodiment of the present invention, the upper rotating part 31 and the lower rotating part 32 on the rotating part group 3 of each universal ball unit are both processed into external gears. The rotation axis of the external gear of the upper rotating part 31 is its hinge axis with the first moving platform 2, and the rotation axis of the external gear of the lower rotating part 32 is its hinge axis with the second moving platform 1; the upper rotating part 31 on the rotating part group of each universal ball unit is in gear meshing transmission with the lower rotating part 32 of the universal ball unit located above it.

[0039] As Figure 6 shows, it is a schematic diagram of gear transmission in a mirror-symmetrical relationship, that is, the upper rotating part 31 and the lower rotating part 32 in gear meshing transmission are always in a mirror-symmetrical relationship, that is, the angle between the upper rotating part 31 and the first moving platform 2 within its unit is always equal to the angle between the lower rotating part 32 and the second moving platform 1 within its unit. Due to the mirror characteristics within the unit and the mirror characteristics of the connected universal ball units, the motion form of the universal ball will be transmitted along the universal ball chain, and the universal ball chain will be bent into a circular arc with a constant curvature, as Figure 7 shows. Figure 7 For Figure 5 the universal ball structure composed of the units shown. Of course, it should be noted that the transmission form to achieve the mirror-symmetrical relationship is not limited to gear transmission. For example, Figure 6 also provides a mechanism sketch of the implementation method of the connecting rod slider mechanism. In addition, the implementation form of gear transmission is not limited to the Figure 6 mirror-symmetrical relationship shown.

[0040] The two moving platforms of the adjacent universal ball units of the present invention that are in contact and connected with each other can be of an integral structure, and the upper rotating member 31 of the universal ball unit and the lower rotating member 32 of its adjacent universal ball unit are also of an integral structure. As Figure 8 shown, it is a schematic diagram of a universal ball structure composed of universal ball units in an integral structure form; in such a universal ball unit of an integral structure, the upper rotating member 31 and the lower rotating member 32 of its adjacent universal ball unit share the same hinge axis. The adjacent universal ball units on the universal ball chain have inconsistent forms, but the two universal ball units separated by one universal ball unit have the same form.

[0041] In terms of specific applications, the universal ball chain composed of the universal ball units of the present invention can achieve the transmission of motion on the chain. For example, the two-degree-of-freedom universal ball chain composed of the universal ball units as Figure 1 shown can be used as a robotic arm, which can bend in two directions, with a camera fixed at the end, and can have openings inside for the camera cable to pass through, for industrial inspection, such as inserting into the fuel tank of an aeroengine to check for internal damage, or as a laparoscopic opening for minimally invasive surgery to explore the abdomen, etc. Any number of universal ball units can be combined according to needs to form different lengths and aspect ratios. The three-degree-of-freedom universal ball chain composed of the universal ball units as Figure 5 shown can be used as a robotic arm and can further extend into a narrow space for exploration. Further, on the basis of the three-degree-of-freedom universal ball chain, multiple sections of universal ball chains can be combined, and each section can be driven by controlling a certain universal ball unit among them to achieve six-degree-of-freedom or more-degree-of-freedom motion.

[0042] Those skilled in the art of the present technology can easily make various changes and modifications according to the written description, drawings, and claims of the present invention without departing from the spirit and scope of the present invention defined by the claims. Any modification and equivalent change made to the above embodiments based on the technical idea and essence of the present invention fall within the protection scope defined by the claims of the present invention.

Claims

1. A universal ball structure for multi-degree-of-freedom unit replication, characterized in that It is composed of any number of universal ball units connected in series. Each universal ball unit includes two motion platforms and at least three groups of rotating parts arranged in parallel between the two motion platforms; the two motion platforms are respectively a first motion platform and a second motion platform, and the first motion platform and the second motion platform each have a rotation center; Each rotating member group includes an upper rotating member, a middle rotating member, and a lower rotating member; one end of the upper rotating member is hinged to the first motion platform, and the axes of the hinge shafts of the two pass through the rotation center of the first motion platform; one end of the lower rotating member is hinged to the second motion platform, and the axes of the hinge shafts of the two pass through the rotation center of the second motion platform; one end of the middle rotating member is hinged to the other end of the upper rotating member, and the axes of the hinge shafts of the two pass through the rotation center of the first motion platform, and the other end of the middle rotating member is hinged to the other end of the lower rotating member, and the axes of the hinge shafts of the two pass through the rotation center of the second motion platform; Two adjacent universal ball units are connected in series through the connection between the motion platforms; the groups of rotating parts of the adjacent universal ball units correspond one to one, and the corresponding groups of rotating parts are transmission-connected.

2. The universal ball structure for multi-degree-of-freedom unit replication according to claim 1, characterized in that, The middle rotating member comprises a first rotating part and a second rotating part which are hinged to each other, wherein the middle rotating member is hinged to the upper rotating member via the first rotating part; and the middle rotating member is hinged to the lower rotating member via the second rotating part.

3. The universal ball structure for multi-degree-of-freedom unit replication according to claim 1, characterized in that, In the universal ball unit, each upper rotating member and the axis of the hinge shaft of the first motion platform are located in the same plane, and the angles between the axes of two adjacent hinge shafts in the plane are equal.

4. The universal ball structure for multi-degree-of-freedom unit replication according to claim 1, characterized in that, In the universal ball unit, each lower rotating member and the axis of the hinge shaft of the second motion platform are located in the same plane, and the angles between the axes of two adjacent hinge shafts in the plane are equal.

5. The universal ball structure for multi-degree-of-freedom unit replication according to claim 1, characterized in that There are three groups of rotating parts in each universal ball unit, and the structures of the three groups of rotating parts are completely the same; the upper rotating part and the lower rotating part have the same structure, and the first motion platform and the second motion platform have the same structure.

6. The universal ball structure for multi-degree-of-freedom unit replication according to claim 1, characterized in that The upper rotating member and the lower rotating member on the rotating member group of each universal ball unit are processed into external gears, the rotation axis of the external gear of the upper rotating member is the hinge axis between it and the first motion platform, and the rotation axis of the external gear of the lower rotating member is the hinge axis between it and the second motion platform; the upper rotating member on the rotating member group of each universal ball unit and the lower rotating member of the universal ball unit located above it are transmitted through gear meshing.

7. The universal ball structure for multi-degree-of-freedom unit replication according to claim 6, characterized in that, The upper rotating member and the lower rotating member driven by gear meshing are always in a mirror-symmetrical relationship, that is, the intersection angle between the upper rotating member and the first moving platform in its unit is always equal to the angle between the lower rotating member and the second moving platform in its unit.

8. The universal ball structure for multi-degree-of-freedom unit replication according to claim 1, wherein, The upper rotating member of the universal ball unit and the lower rotating member of the adjacent universal ball unit are an integrated structure, and the two moving platforms of the adjacent universal ball units that are in contact with each other are an integrated structure.

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